Vitamin D Deficiency
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Vitamin D Deficiency
Vitamin D deficiency occurs when the body has insufficient vitamin D to support normal physiological functions, particularly calcium and phosphate metabolism and the maintenance of healthy bones. Vitamin D can be obtained through skin synthesis following exposure to ultraviolet-B radiation, through certain foods, and through supplements. Because sunlight exposure, diet, age, skin pigmentation, body composition, health conditions, medications, geography, and lifestyle vary substantially among individuals and populations, vitamin D status also varies widely.
Serum 25-hydroxyvitamin D, usually abbreviated 25(OH)D, is the principal laboratory measurement used to assess vitamin D status. However, there remains disagreement over the concentrations that should define deficiency, insufficiency, and optimal vitamin D status. Differences among laboratory methods further complicate comparisons among studies and populations.
Research on vitamin D has expanded far beyond its established role in preventing rickets and osteomalacia. Low vitamin D concentrations have been associated with numerous diseases and adverse health outcomes. In many cases, however, observational associations have not translated into clear benefits from vitamin D supplementation in randomized clinical trials. This distinction is central to understanding current vitamin D research.
Sources and Metabolism of Vitamin D
Vitamin D is unusual among nutrients because the body can manufacture it in the skin. Ultraviolet-B radiation converts precursors in the skin into vitamin D3, which is subsequently metabolized by the liver and kidneys into biologically active forms.
The amount produced in the skin depends on several factors. Latitude and season can greatly alter the amount of ultraviolet-B radiation reaching the Earth's surface. At higher latitudes, winter sunlight may provide little effective ultraviolet-B radiation for vitamin D synthesis. Time spent indoors, clothing, sunscreen use, air pollution, and cultural practices can further reduce exposure.
Melanin absorbs ultraviolet radiation, so greater skin pigmentation can reduce the rate of cutaneous vitamin D production under otherwise similar exposure conditions. This biological relationship does not mean that socially defined racial categories provide a precise measure of vitamin D status. Individual circumstances, ancestry, diet, geography, lifestyle, and environmental exposure all matter.
Vitamin D is also obtained from food and supplements. Natural dietary sources are relatively limited, making fortified foods and supplementation important sources in many countries.
Deficiency, Insufficiency, and Measurement
Vitamin D status is ordinarily evaluated by measuring serum 25-hydroxyvitamin D. Although widely used, this measurement is not entirely standardized. Immunoassays, high-performance liquid chromatography, and mass-spectrometry methods can produce somewhat different results.
International efforts have therefore attempted to standardize vitamin D laboratory testing. Assay variability is important because small differences in measurements can cause individuals to be classified differently depending on the laboratory method and deficiency threshold being used.
There is also continuing debate over what blood concentration should be considered deficient or insufficient. Thresholds developed for preventing skeletal disease are sometimes applied to broader health questions even though evidence for higher target concentrations may be uncertain.
Because of these uncertainties, clinical organizations increasingly distinguish between people with recognizable risk factors or medical indications for testing and healthy people without symptoms. Evidence reviewed by the U.S. Preventive Services Task Force has been insufficient to establish that routine screening of asymptomatic adults improves health outcomes.
Global Prevalence
Low vitamin D concentrations occur throughout the world. Research has documented deficiency in Europe, Africa, Asia, the Middle East, Australia, and other regions, although reported prevalence varies substantially depending on the population studied, laboratory method, season, and threshold used.
Deficiency can occur even in regions receiving abundant sunlight. Studies from the Middle East, North Africa, India, and other sunny regions illustrate that sunlight availability alone does not guarantee adequate vitamin D status.
Differences in clothing, indoor lifestyles, urbanization, diet, food fortification, skin pigmentation, age, sex, body composition, and cultural practices can all influence population vitamin D levels.
Migrant populations living at northern latitudes can be particularly vulnerable. People moving from Africa, South Asia, the Middle East, and other regions to northern Europe may experience a combination of darker pigmentation, reduced ultraviolet-B availability, dietary differences, and altered lifestyles that increases the likelihood of low circulating vitamin D.
Major Risk Factors
Vitamin D deficiency is associated with a wide range of environmental, biological, and medical factors.
Limited sunlight exposure is one of the most important. People who spend much of their time indoors, live at high latitudes, cover most of their skin outdoors, or receive little ultraviolet-B exposure may produce less vitamin D in the skin.
Older adults are vulnerable because cutaneous vitamin D synthesis decreases with age. Nursing-home residents can face particularly high risk because of limited outdoor activity, frailty, poor dietary intake, chronic disease, and inadequate supplementation.
Obesity is consistently associated with lower circulating vitamin D concentrations. Proposed explanations include volumetric dilution, distribution of vitamin D into adipose tissue, metabolic differences, reduced physical activity, and lifestyle factors. People with obesity may also require different supplementation strategies to achieve comparable serum concentrations.
Gastrointestinal diseases can cause deficiency by interfering with absorption. Celiac disease, inflammatory bowel disease, cystic fibrosis, short-bowel disorders, and bariatric surgery can impair vitamin D absorption or alter metabolism.
Chronic kidney and liver diseases can interfere with vitamin D metabolism. Kidney disease is especially important because the kidneys participate in converting vitamin D metabolites into biologically active forms.
Certain medications can also increase risk. Antiseizure drugs that induce hepatic enzymes, for example, have been associated with reduced vitamin D concentrations and impaired bone health.
Children and Rickets
Severe vitamin D deficiency during childhood can cause nutritional rickets, a disorder characterized by impaired mineralization of growing bones. Calcium deficiency can also contribute to nutritional rickets, and the relative importance of vitamin D and calcium varies among populations.
Infants are particularly vulnerable because breast milk ordinarily contains relatively little vitamin D unless maternal intake or supplementation is sufficiently high. Many public-health guidelines therefore recommend vitamin D supplementation for breastfed infants.
Children and adolescents with limited sunlight exposure, restrictive diets, malabsorption disorders, obesity, or certain chronic illnesses may also be at increased risk.
Treatment studies have examined daily, intermittent, and higher-dose supplementation regimens. Appropriate treatment depends on age, severity, underlying disease, calcium intake, and clinical circumstances.
Pregnancy, Lactation, and Reproductive Health
Maternal vitamin D status affects fetal and neonatal vitamin D concentrations. Deficiency during pregnancy has been studied in relation to preeclampsia, gestational diabetes, preterm birth, low birth weight, fetal development, and neonatal health.
Observational studies frequently report associations between low maternal vitamin D and adverse pregnancy outcomes. Supplementation trials, however, have produced a more complicated picture. Supplementation reliably improves maternal and newborn vitamin D concentrations, but evidence that it prevents every proposed pregnancy complication is less certain.
Vitamin D has also been investigated in fertility, in vitro fertilization, polycystic ovary syndrome, testosterone regulation, and male reproductive function. These areas remain active fields of research, and findings are not uniformly consistent.
Older Adults, Bone Health, Falls, and Frailty
Vitamin D has an established biological role in skeletal health. Severe deficiency can produce osteomalacia in adults and contributes to abnormalities of calcium and bone metabolism.
Older people frequently have lower vitamin D concentrations because of reduced skin synthesis, limited outdoor exposure, diet, frailty, kidney disease, institutionalization, and other illnesses.
Low vitamin D concentrations have been associated with frailty, hip fractures, poorer functional recovery, falls, and mortality after hip fracture. These associations do not necessarily mean that increasingly large doses of vitamin D prevent these outcomes.
Randomized trials demonstrate the importance of dose and dosing pattern. Very large intermittent or annual doses have not reliably prevented falls or fractures and, in some studies, have increased fall or fracture risk. More vitamin D is therefore not automatically better.
Obesity, Diabetes, and Metabolic Health
Low vitamin D is common in obesity and has been associated observationally with insulin resistance, metabolic syndrome, type 2 diabetes, hypertension, and abnormal lipid profiles.
These relationships have generated considerable interest in vitamin D as a possible metabolic treatment. Randomized supplementation trials, however, have generally produced smaller and less consistent benefits than observational studies might suggest.
Trials in people with obesity, metabolic syndrome, prediabetes, and diabetes often show that supplementation raises serum vitamin D concentrations without producing large improvements in body weight, glucose control, insulin resistance, blood pressure, or lipid profiles.
This discrepancy illustrates an important principle in vitamin D research: low vitamin D can be a marker or consequence of poor health without necessarily being the principal cause of the associated disease.
Cardiovascular Disease, Cancer, and Mortality
Low vitamin D concentrations have been associated observationally with cardiovascular disease and increased mortality. Research has examined atrial fibrillation, myocardial infarction, stroke, heart failure, cardiovascular mortality, and all-cause mortality.
Large randomized trials and meta-analyses generally have not shown that routine vitamin D supplementation substantially reduces major cardiovascular events in the general population.
Cancer research has produced a somewhat different pattern. Supplementation does not appear to substantially reduce total cancer incidence. Some meta-analyses have reported possible reductions in cancer mortality, particularly with regular daily supplementation rather than large intermittent doses, but the magnitude and clinical significance of this finding remain subjects of investigation.
Infection, Respiratory Disease, and Critical Illness
Vitamin D affects immune function, prompting extensive research into respiratory infections, tuberculosis, asthma, chronic obstructive pulmonary disease, cystic fibrosis, sepsis, critical illness, and COVID-19.
Some analyses suggest that regular vitamin D supplementation may modestly reduce acute respiratory infections, particularly among people who begin with very low vitamin D concentrations.
Observational studies during the COVID-19 pandemic frequently found lower vitamin D concentrations among people experiencing more severe disease. Such findings were vulnerable to confounding because older age, obesity, chronic illness, limited activity, and hospitalization can themselves influence vitamin D status.
Trials in critically ill patients have generally not demonstrated convincing reductions in mortality from high-dose vitamin D therapy.
Neurological and Mental Health Conditions
Vitamin D has been studied in depression, schizophrenia, dementia, Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, migraine, and chronic pain.
Many observational studies report lower vitamin D concentrations among people with these conditions. Low vitamin D has also been associated with cognitive impairment and dementia in prospective studies.
However, associations do not establish that vitamin D deficiency causes these disorders. Illness can reduce outdoor activity, change diet, affect metabolism, and produce other behaviors that themselves lower vitamin D levels.
Supplementation studies in neurological and psychiatric disorders have produced mixed results. Evidence remains insufficient to treat vitamin D as a general therapy for these conditions outside correction of genuine deficiency or other established clinical indications.
Autoimmune and Inflammatory Disorders
Vitamin D participates in immune regulation and has consequently been studied in rheumatoid arthritis, systemic lupus erythematosus, autoimmune thyroid disease, inflammatory bowel disease, psoriasis, vitiligo, alopecia areata, and atopic dermatitis.
Patients with many of these diseases have higher rates of low vitamin D than comparison populations. The reasons may include inflammation, reduced activity, avoidance of sunlight, medications, malabsorption, obesity, or disease-related metabolic changes.
Randomized supplementation trials generally provide less consistent evidence of improvement in underlying disease activity than observational associations might suggest.
Gastrointestinal, Liver, and Kidney Disease
Gastrointestinal disorders can contribute directly to deficiency through malabsorption. Celiac disease, Crohn's disease, ulcerative colitis, cystic fibrosis, and bariatric surgery are among the conditions in which vitamin D monitoring may be clinically relevant.
Vitamin D status often improves when the underlying intestinal disorder is successfully treated. In celiac disease, for example, healing after adherence to a gluten-free diet may improve nutrient absorption and vitamin D metabolism.
Chronic liver disease can disrupt vitamin D metabolism, while chronic kidney disease affects conversion of vitamin D into biologically active metabolites and is closely connected with abnormalities of calcium, phosphate, parathyroid hormone, and bone metabolism.
Vitamin D deficiency is also common among kidney-transplant recipients, although research continues into whether supplementation materially improves graft outcomes, rejection rates, infections, or mortality.
Skin, Hair, and Oral Health
Research has identified associations between low vitamin D and several dermatological conditions, including alopecia areata, psoriasis, vitiligo, acne, and atopic dermatitis.
Vitamin D deficiency has also been investigated in periodontal disease, dental caries, and oral health. Evidence appears stronger for some associations, such as periodontitis, than for others.
As elsewhere in vitamin D research, demonstrating that patients with a disease have lower vitamin D levels does not by itself establish that deficiency caused the disease or that supplementation will cure it.
Screening and Testing
Routine vitamin D testing became increasingly common as interest in possible nonskeletal health effects expanded. More recent guidelines have placed greater emphasis on selective testing.
Testing is most clinically useful when results are likely to influence management, such as in individuals with suspected nutritional deficiency, rickets, osteomalacia, malabsorption, certain metabolic bone disorders, kidney disease, or other relevant medical conditions.
Routine population-wide screening of healthy asymptomatic adults has not been demonstrated to improve major health outcomes.
Interpretation of test results also requires awareness of laboratory variability and disagreement over thresholds. A laboratory value should therefore be considered in the context of symptoms, medical history, risk factors, calcium metabolism, and the clinical reason for testing.
Prevention and Treatment
Preventing vitamin D deficiency can involve a combination of safe sunlight exposure, dietary sources, fortified foods, and supplementation.
Food fortification is particularly important from a public-health perspective because it can raise vitamin D intake across large populations without requiring individuals to recognize that they are at risk.
Supplementation is effective for increasing serum vitamin D concentrations and is essential in treating genuine deficiency. The appropriate dose varies with age, baseline vitamin D level, obesity, pregnancy, malabsorption, kidney or liver disease, medication use, and other clinical factors.
Very high doses should not be assumed to provide additional health benefits. Some large intermittent-dose studies have produced unfavorable outcomes, particularly involving falls among older adults.
Correction of deficiency should therefore be distinguished from taking increasingly large vitamin D doses in an attempt to prevent unrelated diseases.
Understanding the Evidence
Vitamin D research illustrates the difference between observational association and causation.
People with chronic illness frequently have lower vitamin D concentrations. This can occur because disease reduces outdoor activity, changes nutrition, promotes obesity or frailty, affects intestinal absorption or metabolism, or increases hospitalization and institutionalization.
Consequently, low vitamin D may sometimes contribute to disease, sometimes result from disease, and sometimes simply accompany other risk factors.
Randomized clinical trials are therefore particularly important. In several fields—including cardiovascular disease, metabolic disorders, critical illness, and some inflammatory diseases—strong observational associations have been followed by supplementation trials showing little or no major clinical benefit.
At the same time, vitamin D remains essential to normal physiology. Preventing and treating genuine deficiency, rickets, osteomalacia, and related disturbances of mineral and bone metabolism remains well established.
Conclusion
Vitamin D deficiency is a widespread nutritional and clinical problem influenced by sunlight exposure, latitude, season, skin pigmentation, diet, age, obesity, pregnancy, gastrointestinal absorption, chronic disease, medication use, and lifestyle.
Its clearest established consequences involve calcium metabolism and skeletal health, including nutritional rickets in children and osteomalacia in adults. Deficiency is especially common among older adults, institutionalized populations, people with limited sunlight exposure, individuals with malabsorptive disorders, some migrant populations, and people with obesity or chronic kidney, liver, or gastrointestinal disease.
Low vitamin D concentrations have also been associated with a wide range of cardiovascular, metabolic, infectious, neurological, psychiatric, autoimmune, inflammatory, reproductive, dermatological, and other disorders. These associations have generated important research but should not automatically be interpreted as evidence that vitamin D deficiency causes each condition.
Clinical trials show that correcting true deficiency reliably raises vitamin D levels and protects against established deficiency-related disorders. They provide much less consistent evidence that supplementation prevents the many nonskeletal diseases associated observationally with low vitamin D.
The modern evidence therefore supports a balanced approach: identify and treat people at meaningful risk of deficiency, ensure adequate vitamin D and calcium for skeletal health, use laboratory testing when clinically appropriate, avoid unnecessary population-wide screening, and distinguish carefully between observational associations and demonstrated benefits of supplementation.
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Vitamin D Deficiency — Categorized, Deduplicated, and Reverse-Sorted Research Sources
Clinical Guidelines, Definitions, Measurement, and Screening
1. The 2024 Endocrine Society Guideline on Vitamin D: Comprehensive Summary and Critical Appraisal | Multiple authors | Nutrients | 2026
Reviews the Endocrine Society's updated vitamin D recommendations, including testing, supplementation, target concentrations, evidence quality, and areas of continuing controversy.
2. Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline | Marie B. Demay et al. | Journal of Clinical Endocrinology & Metabolism | 2024
Updates recommendations on vitamin D supplementation and testing, emphasizing that routine screening and high-dose supplementation are generally unsupported in healthy adults younger than 75.
3. Analytical Methods for 25-Hydroxyvitamin D: Advantages and Limitations of Existing Assays | Multiple authors | Journal of Steroid Biochemistry and Molecular Biology | 2022
Reviews immunoassays, HPLC, LC-MS/MS, analytical variability, and efforts to standardize laboratory measurement of vitamin D status.
4. Screening for Vitamin D Deficiency in Adults: Updated Evidence Report and Systematic Review [PMID/USPSTF Evidence Review | Leila C. Kahwati et al. | JAMA | 2021]
Finds insufficient evidence that screening asymptomatic adults for vitamin D deficiency improves major health outcomes and reviews treatment trials in people with low levels.
5. Vitamin D Deficiency in Adults: Screening [USPSTF Recommendation | U.S. Preventive Services Task Force | USPSTF | 2021]
Concludes that evidence is insufficient to determine the balance of benefits and harms of routine screening for vitamin D deficiency in asymptomatic adults.
6. Vitamin D Testing: Advantages and Limits of the Current Assays | Multiple authors | European Journal of Clinical Nutrition | 2020
Critically reviews methods for measuring vitamin D metabolites and the limitations that complicate interpretation of deficiency cutoffs.
7. An Evaluation of Total 25-Hydroxyvitamin D Assay Standardization | Multiple authors | Journal of Steroid Biochemistry and Molecular Biology | 2019
Compares seven vitamin D assays and demonstrates clinically important discrepancies in how patients can be classified as deficient or adequate.
8. Vitamin D Insufficiency: Definition, Diagnosis and Management | Multiple authors | Clinical review | 2018
Reviews definitions of deficiency and insufficiency, measurement of serum 25-hydroxyvitamin D, skeletal consequences, supplementation, and disagreements over optimal thresholds.
9. 25-Hydroxyvitamin D Testing: Immunoassays Versus Tandem Mass Spectrometry | Multiple authors | Clinics in Laboratory Medicine | 2018
Compares the major laboratory methods used to measure vitamin D and explains why differences between assays can change deficiency classification.
10. Toward Clarity in Clinical Vitamin D Status Assessment: 25(OH)D Assay Standardization | Multiple authors | Journal of Clinical Densitometry | 2017
Explains how differences among laboratory assays complicate definitions of deficiency and summarizes the Vitamin D Standardization Program.
11. General Steps to Standardize the Laboratory Measurement of Serum Total 25-Hydroxyvitamin D | Multiple authors | Journal of AOAC International | 2017
Provides practical laboratory procedures for achieving standardized and traceable measurement of circulating 25-hydroxyvitamin D.
12. Vitamin D Measurement Standardization: The Way Out of the Chaos | Multiple authors | Journal of Steroid Biochemistry and Molecular Biology | 2017
Reviews international efforts to reduce laboratory variability and improve comparison of vitamin D deficiency data among studies and countries.
13. Measurement of Circulating 25-Hydroxyvitamin D: A Historical Review | Multiple authors | Clinical Chemistry and Laboratory Medicine | 2017
Traces the development of vitamin D testing from early assays through modern mass spectrometry and explains continuing harmonization problems.
14. Standardizing Vitamin D Assays: The Way Forward | Multiple authors | Journal of Bone and Mineral Research | 2014
Discusses between-assay variation and why standardized measurements are necessary for establishing reliable deficiency thresholds.
15. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: An Endocrine Society Clinical Practice Guideline | Michael F. Holick et al. | Journal of Clinical Endocrinology & Metabolism | 2011
Landmark clinical guideline addressing who should be tested, how deficiency should be treated, recommended supplementation, and populations requiring higher vitamin D intake.
16. 25-Hydroxyvitamin D Measurement, 2009: A Review for Clinicians | Multiple authors | Clinical Review | 2009
Discusses laboratory variability and argues for selective testing of patients at meaningful clinical risk rather than indiscriminate population screening.
Global Prevalence, Population Differences, Migration, and Pigmentation
17. A Systematic Review and Meta-analysis of Vitamin D Status of Apparently Healthy Adults in Worldwide Regions | Multiple authors | Systematic Review and Meta-analysis | 2026
Analyzes almost 400,000 participants from multiple world regions and reports substantial vitamin D deficiency even among apparently healthy adults, with particularly high prevalence in the Middle East.
18. Vitamin D Nutritional Status in the Middle East and North Africa Region: A Systematic Review and Meta-analysis | Multiple authors | Systematic review and meta-analysis | 2025
Finds widespread low vitamin D concentrations across Middle Eastern and North African populations despite abundant sunlight and discusses nutrition and fortification strategies.
19. A Systematic Review of Evidence, Misinterpretations, and the Urgent Need for Population-Specific Reference Standards Related to Vitamin D Deficiency in India | Multiple authors | Cureus | 2025
Questions whether universal vitamin D thresholds accurately reflect biological deficiency in Indian populations and examines pigmentation, calcium intake, sunlight, and population differences.
20. Navigating Complexities: Vitamin D, Skin Pigmentation, and Race | Multiple authors | Journal of Clinical Endocrinology & Metabolism | 2024
Explains the biological influence of melanin on cutaneous vitamin D synthesis while cautioning against using socially defined racial categories as simple biological proxies.
21. High Prevalence of Vitamin D Deficiency in Asia: A Systematic Review and Meta-analysis | Zhiwei Jiang et al. | Critical Reviews in Food Science and Nutrition | 2023
Synthesizes studies across Asia and documents substantial regional, demographic, and lifestyle variation in vitamin D deficiency.
22. Vitamin D Deficiency in South-East Asian Children: A Systematic Review | Multiple authors | Pediatric systematic review | 2022
Finds vitamin D deficiency common among children in Southeast Asia, particularly newborns, adolescent females, and urban populations.
23. High Prevalence of Vitamin D Deficiency Among South Asian Adults: A Systematic Review and Meta-analysis | Multiple authors | Systematic review and meta-analysis | 2021
Estimates a high pooled prevalence across India, Pakistan, Bangladesh, Nepal, and Sri Lanka and reports particularly high deficiency among women.
24. Prevalence of Vitamin D Deficiency in Africa: A Systematic Review and Meta-analysis | Reagan M. Mogire et al. | Lancet Global Health | 2020
Analyzes data from 23 African countries and identifies substantial vitamin D deficiency, with variation by region, urbanization, sex, and age.
25. Current Vitamin D Status in European and Middle East Countries and Strategies to Prevent Vitamin D Deficiency | Multiple authors | European Journal of Endocrinology | 2019
European Calcified Tissue Society position statement reviews regional prevalence and population strategies including supplementation and food fortification.
26. Prevalence of Vitamin D Deficiency in Iran: A Systematic Review and Meta-analysis | Multiple authors | Systematic review and meta-analysis | 2018
Estimates widespread deficiency in Iran and shows substantially higher prevalence among women than men.
27. Global Prevalence and Disease Burden of Vitamin D Deficiency: A Roadmap for Action in Low- and Middle-Income Countries | Daniel E. Roth et al. | Annals of the New York Academy of Sciences | 2018
Reviews vitamin D deficiency as a global public-health problem and discusses vulnerable groups, population surveillance, food fortification, supplementation, and evidence gaps.
28. Vitamin D Deficiency in Europe: Pandemic? | Kevin D. Cashman et al. | American Journal of Clinical Nutrition | 2016
Uses standardized measurements to demonstrate substantial vitamin D deficiency across European populations, especially during winter and among darker-skinned ethnic minorities.
29. The Prevalence of Vitamin D Deficiency Among Dark-Skinned Populations According to Stage of Migration and Region of Birth | Catherine A. Martin et al. | Nutrition | 2016
Meta-analysis estimates very high vitamin D deficiency prevalence among darker-skinned migrant populations and examines differences according to geographic origin.
30. Vitamin D Status in Recently Arrived Immigrants From Africa and Asia | Multiple authors | BMJ Open | 2013
Finds a high prevalence of low vitamin D among newly arrived migrants from the Middle East, South Asia, and sub-Saharan Africa living in Norway.
31. Prevalence of Vitamin D Deficiency and Its Determinants in Australian Adults | Multiple authors | Clinical Endocrinology | 2012
National population study finds deficiency associated with female sex, older age, obesity, physical inactivity, season, and non-European ancestry.
32. Prevalence of Vitamin D Deficiency Among Turkish, Moroccan, Indian and Sub-Sahara African Populations in Europe | Multiple authors | Osteoporosis International | 2010
Reviews evidence showing markedly poorer vitamin D status among several migrant populations in Europe compared with native European populations.
33. Vitamin D Deficiency: A Global Perspective | Ann Prentice | Nutrition Reviews | 2008
Reviews worldwide vitamin D status, nutritional rickets, osteomalacia, calcium intake, geographic differences, and controversies surrounding serum 25-hydroxyvitamin D thresholds.
34. Vitamin D Deficiency | Michael F. Holick | New England Journal of Medicine | 2007
Influential review of vitamin D metabolism, skeletal disease, risk factors, sunlight exposure, diagnosis, prevention, and treatment of vitamin D deficiency.
35. Vitamin D Status and Nutrition in Europe and Asia | Multiple authors | Journal of Steroid Biochemistry and Molecular Biology | 2007
Reviews geographic variation in vitamin D status and the influence of latitude, diet, fortification, clothing, migration, pregnancy, and urbanization.
36. Vitamin D Deficiency: A Global Perspective | Multiple authors | International review | 2006
Reviews the worldwide burden of low vitamin D, emphasizing sunlight, latitude, skin pigmentation, aging, diet, osteoporosis, rickets, and osteomalacia.
37. Season, Latitude, and Ability of Sunlight to Promote Synthesis of Vitamin D3 in Skin | Multiple authors | Nutrition Reviews | 1989
Describes how latitude, season, pigmentation, and lifestyle strongly influence the skin's ability to synthesize vitamin D from ultraviolet-B radiation.
38. Influence of Season and Latitude on the Cutaneous Synthesis of Vitamin D3 | Michael F. Holick et al. | Journal of Clinical Endocrinology & Metabolism | 1988
Demonstrates experimentally that winter sunlight at northern latitudes can be insufficient for meaningful cutaneous vitamin D production.
Pregnancy, Lactation, Fertility, and Reproductive Health
39. Vitamin D Supplementation During Pregnancy and Maternal and Neonatal Outcomes: An Umbrella Meta-analysis | Multiple authors | Meta-analysis | 2026
Synthesizes meta-analyses examining gestational diabetes, preeclampsia, premature delivery, low birth weight, fetal growth, stillbirth, and neonatal outcomes.
40. The Association Between Pre-cycle Maternal Vitamin D Status and Reproductive Outcomes in Frozen-Thawed Embryo Transfer | Abdelgader et al. | Systematic review and meta-analysis | 2026
Examines whether low maternal vitamin D before frozen embryo transfer is associated with pregnancy and live-birth outcomes.
41. Prevalence and Influencing Factors of Vitamin D Deficiency in Women With Polycystic Ovary Syndrome | Manman Yao et al. | Frontiers in Nutrition | 2026
Meta-analysis estimates that vitamin D deficiency is widespread among women with PCOS and examines obesity, insulin resistance, inflammation, and geographic differences.
42. The Association Between Vitamin D and Polycystic Ovary Syndrome in Women | Multiple authors | Systematic Review | 2026
Reviews observational and interventional evidence concerning vitamin D deficiency, metabolic abnormalities, ovulatory function, and supplementation in PCOS.
43. The Effect of Vitamin D Deficiency During Pregnancy on Adverse Birth Outcomes in Neonates | Multiple authors | Systematic review and meta-analysis | 2024
Reviews cohort evidence linking maternal vitamin D deficiency with low birth weight and other adverse neonatal outcomes.
44. Optimizing Vitamin D Status in Polycystic Ovary Syndrome | Kelsey M. Cochrane et al. | Nutrition Reviews | 2024
Systematic review and dose-response meta-analysis examines how different supplementation regimens affect vitamin D concentrations in women with PCOS.
45. Vitamin D and Preeclampsia: A Systematic Review and Meta-analysis | Multiple authors | SAGE Open Medicine | 2023
Evaluates observational and randomized evidence relating maternal vitamin D deficiency and supplementation to preeclampsia.
46. Vitamin D and In Vitro Fertilization: A Systematic Review | Multiple authors | Reproductive medicine review | 2023
Finds inconsistent evidence that serum vitamin D status predicts IVF success, highlighting substantial differences among studies and populations.
47. Vitamin D Levels in Early and Middle Pregnancy and Preeclampsia: A Systematic Review and Meta-analysis | Multiple authors | Nutrients | 2022
Reports an association between low maternal vitamin D levels and increased preeclampsia risk across observational studies.
48. Systematic Review and Meta-analysis of Vitamin D Deficiency in Different Pregnancy Periods and Preterm Birth | Rui-Han Lian et al. | Medicine | 2021
Examines vitamin D status by trimester and suggests that deficiency during mid-pregnancy may be particularly relevant to preterm birth risk.
49. Maternal Vitamin D Status and Risk of Gestational Diabetes Mellitus | Multiple authors | Systematic review and meta-analysis | 2021
Prospective evidence indicates that vitamin D-deficient pregnant women have a moderately increased risk of gestational diabetes.
50. Maternal Vitamin D Deficiency During Pregnancy and Low Birth Weight | Multiple authors | Systematic review and meta-analysis | 2019
Finds maternal deficiency associated with increased odds of delivering a low-birth-weight infant.
51. Vitamin D and Male Fertility: An Updated Review | Multiple authors | World Journal of Men's Health | 2019
Reviews vitamin D receptors in male reproductive tissues and the mixed evidence relating vitamin D status to testosterone, semen quality, and fertility.
52. Effectiveness of Prenatal Vitamin D Deficiency Screening and Treatment Program | Maryam Rostami et al. | Journal of Clinical Endocrinology & Metabolism | 2018
Randomized field trial examines screening and treatment of vitamin D deficiency during pregnancy and resulting maternal vitamin D levels and pregnancy outcomes.
53. Vitamin D, PCOS and Androgens in Men | Christian Trummer et al. | Endocrine Connections | 2018
Reviews vitamin D status in women with PCOS and evidence concerning vitamin D, testosterone, hypogonadism, and reproductive physiology in men.
54. Vitamin D Deficiency in Pregnancy and Its Impact on the Fetus, Newborn and Childhood | Marilyn Urrutia-Pereira, Dirceu Solé | Revista Paulista de Pediatria | 2015
Reviews maternal and childhood consequences of vitamin D deficiency and discusses risk factors, prevention, and supplementation.
55. Maternal Vitamin D Supplementation During Pregnancy Prevents Vitamin D Deficiency in the Newborn | Multiple authors | Clinical Endocrinology | 2015
Randomized trial finds maternal supplementation substantially improves umbilical-cord vitamin D concentrations in newborns.
56. Implications of Maternal Vitamin D Deficiency for the Fetus, the Neonate and the Young Infant | Multiple authors | European Journal of Nutrition | 2013
Reviews maternal deficiency, fetal vitamin D status, neonatal health, infancy, and supplementation during pregnancy and lactation.
57. Maternal Vitamin D Supplementation to Meet the Needs of the Breastfed Infant | Multiple authors | Journal of Human Lactation | 2013
Reviews evidence concerning maternal supplementation as a means of increasing breast-milk vitamin D and preventing deficiency in exclusively breastfed infants.
58. Maternal Vitamin D Deficiency: Fetal and Neonatal Implications | Christopher S. Kovacs | Seminars in Fetal and Neonatal Medicine | 2013
Reviews maternal-fetal calcium transfer, neonatal vitamin D physiology, infant hypocalcemia, and the development of nutritional rickets.
59. Randomized Controlled Trial of Vitamin D Supplementation in Pregnancy in a Population With Endemic Vitamin D Deficiency | Adekunle Dawodu et al. | Journal of Clinical Endocrinology & Metabolism | 2013
Compares 400, 2,000, and 4,000 IU daily supplementation in pregnant women and evaluates maternal and cord-blood vitamin D concentrations.
60. Effect of Vitamin D Administration in Vitamin-D-Deficient Pregnant Women on Maternal and Neonatal Serum Calcium and Vitamin D | Sima Hashemipour et al. | British Journal of Nutrition | 2013
Randomized trial examines high-dose treatment of vitamin-D-deficient pregnant women and maternal and neonatal calcium and vitamin D status.
61. Vitamin D and Fertility: A Systematic Review | Multiple authors | European Journal of Endocrinology | 2012
Reviews vitamin D receptors in reproductive tissues and evidence concerning fertility, PCOS, semen quality, testosterone, and assisted reproduction.
62. Vitamin D Deficiency and Supplementation During Pregnancy | Multiple authors | Clinical Endocrinology | 2009
Prospective randomized study compares daily, single-dose, and no vitamin D supplementation among pregnant women from several ethnic groups.
63. Vitamin D in Pregnancy and Lactation: Maternal, Fetal, and Neonatal Outcomes | Multiple authors | American Journal of Clinical Nutrition | 2008
Examines calcium and vitamin D physiology during pregnancy and lactation and explains why exclusively breastfed infants are vulnerable to deficiency.
Children, Adolescents, and Rickets
64. Low Dose Versus High Dose Vitamin D for Treatment of Nutritional Rickets | Multiple authors | Indian Pediatrics | 2026
Compares lower- and higher-dose vitamin D treatment regimens for nutritional rickets and evaluates efficacy and safety.
65. Daily Versus Fortnightly Oral Vitamin D3 in Treatment of Symptomatic Vitamin D Deficiency in Children | Kumar Arghya Prasanna Mondal et al. | Clinical Endocrinology | 2024
Compares daily vitamin D therapy with intermittent high-dose treatment among children with symptomatic deficiency.
66. Vitamin D Supplementation for Improving Bone Density in Vitamin D-Deficient Children and Adolescents | Feitong Wu et al. | American Journal of Clinical Nutrition | 2023
Uses individual-participant trial data to investigate whether supplementation improves bone mineral density specifically among vitamin-D-deficient children and adolescents.
67. Treatment of Vitamin D Deficiency in Children | Multiple authors | Expert Review | 2023
Reviews diagnostic thresholds, prevention, supplementation, treatment regimens, rickets, and hypocalcemia in vitamin-D-deficient children.
68. Influence of Vitamin D Supplementation on Growth, Body Composition, and Pubertal Development Among School-Aged Children | Multiple authors | JAMA Pediatrics | 2023
Large randomized trial in a population with widespread deficiency found that supplementation corrected vitamin D levels but did not substantially alter growth, body composition, or pubertal development.
69. An Update on Vitamin D Deficiency in the Twenty-First Century: Nature and Nurture | Ashley J. Stoffers, David R. Weber, Michael A. Levine | Current Opinion in Endocrinology, Diabetes and Obesity | 2022
Reviews modern causes of childhood vitamin D deficiency and rickets, including nutrition, limited sunlight, genetics, and abnormalities of vitamin D metabolism.
70. Vitamin D Deficiency in Childhood: Old Lessons and Current Challenges | Multiple authors | Journal of Pediatric Endocrinology and Metabolism | 2018
Describes the re-emergence of childhood deficiency in developed countries and examines obesity, lifestyle, inadequate sunlight, screening, and supplementation.
71. The Optimal Dosage Regimen of Vitamin D Supplementation for Correcting Deficiency in Adolescents | Feitong Wu et al. | European Journal of Clinical Nutrition | 2018
Randomized pilot trial compares monthly and three-monthly vitamin D dosing for correcting adolescent vitamin D deficiency.
72. Global Consensus Recommendations on Prevention and Management of Nutritional Rickets | Craig F. Munns et al. | Journal of Clinical Endocrinology & Metabolism | 2016
Establishes international recommendations for diagnosing, preventing, and treating nutritional rickets caused by vitamin D and/or calcium deficiency.
73. A Review on Vitamin D Deficiency Treatment in Pediatric Patients | Multiple authors | Journal of Pediatric Pharmacology and Therapeutics | 2014
Reviews treatment of pediatric deficiency caused by nutritional problems, malabsorption, medications, and other conditions.
74. Rickets and Vitamin D Deficiency in Children and Adolescents | John M. Pettifor | Endocrinology and Metabolism Clinics of North America | 2005
Reviews the causes, epidemiology, clinical features, prevention, and treatment of vitamin-D-deficiency rickets and calcium-deficiency rickets.
Older Adults, Bone Health, Falls, and Frailty
75. The Association Between Vitamin D Deficiency and Mortality After Hip Fractures | Multiple authors | Journal of Nutritional Science and Vitaminology | 2024
Systematic review examines whether vitamin D deficiency is associated with higher mortality following hip fracture.
76. The Global Prevalence of Vitamin D Deficiency in the Elderly | Multiple authors | Indian Journal of Orthopaedics | 2024
Meta-analysis estimates the worldwide burden of vitamin D deficiency among older adults and examines regional variability.
77. Vitamin D Deficiency in Nursing Home Residents: A Systematic Review | Multiple authors | Nutrition Reviews | 2023
Reports very high deficiency rates among institutionalized older adults and identifies limited sunlight, poor diet, frailty, kidney disease, and inadequate supplementation as contributors.
78. Does Vitamin D Deficiency Affect Functional Outcomes in Hip Fracture Patients? | Multiple authors | Meta-analysis | 2023
Examines whether deficient vitamin D status predicts poorer physical recovery and quality of life following hip fracture.
79. Impact of Vitamin D Deficiency on Mortality in Patients With Hip Fracture | Multiple authors | Journal of the American Geriatrics Society | 2023
Evaluates deficiency and mortality after hip fracture and highlights the importance of accounting for age, illness, and other confounders.
80. Vitamin D Supplementation and Risk of Falling: Outcomes From the D-Health Trial | Multiple authors | Journal of Cachexia, Sarcopenia and Muscle | 2021
Large randomized trial examines whether monthly high-dose vitamin D reduces falls among adults aged 60–84.
81. Low Vitamin D Levels and Frailty Status in Older Adults | Multiple authors | Systematic review and meta-analysis | 2020
Finds lower serum vitamin D concentrations among frail and prefrail older adults, although causality remains uncertain.
82. Low 25-Hydroxyvitamin D Levels and the Risk of Frailty Syndrome | Multiple authors | Systematic review and dose-response meta-analysis | 2018
Reports a dose-response association between lower circulating vitamin D and higher frailty risk in observational studies.
83. Association of Vitamin D Deficiency and Frailty | Jianghua Zhou et al. | Maturitas | 2016
Meta-analysis finds significantly greater frailty among older adults with low vitamin D concentrations.
84. Annual High-Dose Oral Vitamin D and Falls and Fractures in Older Women | Kerrie M. Sanders et al. | JAMA | 2010
Randomized trial found that a very large annual bolus of vitamin D did not prevent falls or fractures and was associated with increased risk.
85. Does Vitamin D Stop Inpatients Falling? A Randomised Controlled Trial | Elizabeth Burleigh et al. | Age and Ageing | 2007
Tests vitamin D plus calcium for fall prevention among older hospitalized patients.
86. Effects of Vitamin D and Calcium Supplementation on Falls | Multiple authors | Journal of Bone and Mineral Research | 2003
Randomized study in older women reported improved musculoskeletal function and fewer falls with vitamin D plus calcium compared with calcium alone.
Obesity, Diabetes, Metabolic Syndrome, PCOS, and Blood Pressure
87. Vitamin D Deficiency in Obesity: Epidemiological Evidence, Biological Mechanisms, and Clinical Considerations | Reem J. Al Argan et al. | Obesity Medicine | 2025
Reviews evidence that obesity lowers circulating vitamin D through volumetric dilution, adipose distribution, metabolic dysfunction, and lifestyle factors.
88. The Interplay Between Childhood Obesity and Vitamin D Deficiency: Mechanisms and Implications | Multiple authors | Frontiers in Pediatrics | 2025
Examines the frequent coexistence of childhood obesity and vitamin D deficiency and possible metabolic, inflammatory, and physiological mechanisms linking them.
89. Is Vitamin D Deficiency a Risk Factor for Obesity-Related Morbidity, Prediabetes, and Type 2 Diabetes? | Multiple authors | Endocrinology review | 2025
Reviews vitamin D deficiency in obesity, prediabetes, and type 2 diabetes and discusses whether correction affects metabolic outcomes.
90. Effect of Vitamin D Supplementation on Body Composition, Lipid Profile, and Glycemic Indices in Obesity-Associated Metabolic Syndrome | Multiple authors | Systematic review and meta-analysis | 2025
Finds little consistent evidence that supplementation improves body weight, lipids, glucose control, or insulin resistance in obesity-associated metabolic disorders.
91. Effects of Vitamin D Supplementation on Metabolic Syndrome Parameters in Patients With Obesity or Diabetes | Multiple authors | Journal of Steroid Biochemistry and Molecular Biology | 2024
Meta-analysis finds generally little metabolic improvement from supplementation, although certain deficient subgroups may experience modest benefits.
92. Effects of Vitamin D Supplementation on Cardiometabolic Parameters Among Patients With Metabolic Syndrome | Multiple authors | Systematic review and GRADE evidence synthesis | 2023
Reviews randomized trials and concludes that evidence for improving glucose, blood pressure, triglycerides, or waist circumference remains low or uncertain.
93. Effects of Vitamin D Supplementation in Obese and Overweight Children and Adolescents | Multiple authors | Clinical Nutrition ESPEN | 2023
Reviews supplementation trials in pediatric obesity and finds that vitamin D concentrations rise while cardiometabolic effects remain inconsistent.
94. Serum Vitamin D Status and Metabolic Syndrome: A Systematic Review and Dose-Response Meta-analysis | Kyueun Lee and Jihye Kim | Nutrition Research and Practice | 2021
Finds higher serum vitamin D concentrations associated observationally with lower metabolic syndrome prevalence and incidence.
95. Vitamin D Deficiency in Children and Adolescents With Obesity | Multiple authors | Jornal de Pediatria | 2021
Meta-analysis finds obesity associated with substantially higher odds of vitamin D deficiency in children and adolescents.
96. Is There a Benefit of Vitamin D Supplementation in Deficient Children and Adolescents Suffering From Obesity? | Multiple authors | Meta-analysis | 2021
Examines treatment response in obese vitamin-D-deficient children and suggests obesity may reduce the effectiveness of standard supplementation regimens.
97. Effect of High-Dose Vitamin D Supplementation With Weight Loss on Glucose Homeostasis and Insulin Resistance | Multiple authors | Applied Physiology, Nutrition, and Metabolism | 2020
Randomized trial evaluates high-dose vitamin D in vitamin-D-deficient adults with obesity undergoing a weight-reduction diet.
98. Vitamin D Supplementation and Prevention of Type 2 Diabetes | Anastassios G. Pittas et al. | New England Journal of Medicine | 2019
The D2d randomized trial evaluates 4,000 IU/day vitamin D in adults with prediabetes and its effect on progression to type 2 diabetes.
99. The Effect of Vitamin D3 on Blood Pressure in People With Vitamin D Deficiency | Silu He and Xiyuan Hao | Medicine | 2019
Meta-analysis finds no substantial overall blood-pressure reduction, although some hypertensive and older subgroups appeared to benefit.
100. Effect of Vitamin D Supplementation With Weight Loss on Meta-Inflammation and Fat Mass | Multiple authors | Clinical Endocrinology | 2019
Randomized trial examines whether correction of deficiency alters inflammatory markers, body weight, and fat mass in adults with obesity.
101. Effect of Vitamin D Supplementation on Blood Pressure Parameters in Patients With Vitamin D Deficiency | Liqin Shu et al. | Journal of the American Society of Hypertension | 2018
Finds a small reduction in diastolic blood pressure but limited evidence of broader clinically meaningful blood-pressure effects.
102. Interplay of Vitamin D and Metabolic Syndrome: A Review | Priyanka Prasad and Anita Kochhar | Diabetes & Metabolic Syndrome | 2016
Reviews associations between low vitamin D, obesity, insulin resistance, hypertension, dyslipidemia, and other components of metabolic syndrome.
103. Vitamin D Deficiency in Relation to the Risk of Metabolic Syndrome in Patients With Type 2 Diabetes | Multiple authors | Journal of Nutritional Science and Vitaminology | 2016
Reports an association between lower vitamin D concentrations and metabolic syndrome among older adults with type 2 diabetes.
104. Effect of Vitamin D on Blood Pressure: A Systematic Review and Meta-analysis | Miles D. Witham et al. | Journal of Hypertension | 2009
Reviews randomized trials investigating whether vitamin D supplementation lowers systolic or diastolic blood pressure.
105. Vitamin D Deficiency Is Associated With the Metabolic Syndrome in Morbid Obesity | José I. Botella-Carretero et al. | Clinical Nutrition | 2007
Observational study reports a higher prevalence of metabolic syndrome among severely obese patients with vitamin D deficiency.
Gastrointestinal Disease, Malabsorption, and Bariatric Surgery
106. Vitamin D and Intestinal Diseases: Impact on Intestinal Immunity and Gut Barrier Function | Multiple authors | Review Article | 2026
Reviews vitamin D receptor signaling, intestinal permeability, immune regulation, microbiome composition, and the potential consequences of deficiency for inflammatory intestinal disease.
107. Vitamin D and Malabsorptive Gastrointestinal Conditions: A Bidirectional Relationship? | Multiple authors | Nutrients | 2023
Examines the complex relationship between vitamin D status and gastrointestinal disorders such as celiac disease, inflammatory bowel disease, and conditions following bariatric surgery.
108. The Effect of a Gluten-Free Diet on Vitamin D Metabolism in Celiac Disease: The State of the Art | Multiple authors | Nutrients | 2023
Discusses abnormalities in vitamin D, calcium, parathyroid hormone, and bone metabolism among people with untreated celiac disease and their response to a gluten-free diet.
109. Vitamin D Status and Supplementation Before and After Bariatric Surgery | Multiple authors | Systematic Review and Meta-analysis | 2023
Reports a high prevalence of vitamin D deficiency before bariatric surgery and evaluates supplementation strategies needed to prevent persistent deficiency afterward.
110. Role of Vitamin D in Celiac Disease and Inflammatory Bowel Diseases | Multiple authors | Nutrients | 2022
Reviews evidence connecting vitamin D metabolism, intestinal immunity, mucosal integrity, celiac disease, Crohn's disease, and ulcerative colitis.
111. Vitamin D Therapy in Adults With Inflammatory Bowel Disease | Multiple authors | Inflammatory Bowel Diseases | 2020
Reviews randomized and observational studies and finds supplementation effectively raises vitamin D levels, with possible improvements in some disease-activity measures.
112. The Role of Vitamin D in Inflammatory Bowel Disease: A Guide for Clinical Practice | Multiple authors | Expert Review of Gastroenterology & Hepatology | 2020
Reviews vitamin D status in IBD and cautions that deficiency may frequently be a consequence of inflammation and illness rather than a primary cause.
113. Inflammatory Bowel Disease and Vitamin D | Multiple authors | Clinical Review | 2020
Discusses why low vitamin D concentrations are frequent in IBD and examines associations with recurrence, hospitalization, surgery, and quality of life.
114. The Role of Vitamin D in Inflammatory Bowel Disease: Mechanism to Management | Multiple authors | Nutrients | 2019
Reviews vitamin D receptor signaling, immune regulation, gut microbiota, intestinal inflammation, and supplementation in Crohn's disease and ulcerative colitis.
115. The Value and Significance of 25(OH) and 1,25(OH) Vitamin D Serum Levels in Adult Coeliac Patients | Multiple authors | Digestive and Liver Disease | 2018
Reviews vitamin D measurements in adult celiac disease and evidence that vitamin D status often improves after intestinal recovery on a strict gluten-free diet.
116. Hypovitaminosis D in Bariatric Surgery: A Systematic Review of Observational Studies | Multiple authors | Obesity Surgery | 2016
Shows that low vitamin D is common before bariatric surgery and frequently persists afterward despite supplementation.
117. Vitamin D and the Pathogenesis of Inflammatory Bowel Disease | Multiple authors | Current Gastroenterology Reports | 2016
Examines genetic, epidemiological, animal, and laboratory evidence concerning vitamin D deficiency and the development or severity of inflammatory bowel disease.
118. Association Between Inflammatory Bowel Disease and Vitamin D Deficiency | Multiple authors | Inflammatory Bowel Diseases | 2015
Meta-analysis finds higher odds of vitamin D deficiency among patients with inflammatory bowel disease, including ulcerative colitis, than among controls.
119. Vitamin D Deficiency in Patients With Intestinal Malabsorption Syndromes—Think In and Outside the Gut | Multiple authors | Journal of Digestive Diseases | 2015
Reviews vitamin D deficiency in celiac disease, inflammatory bowel disease, cystic fibrosis, and short-bowel syndrome, emphasizing malabsorption, inflammation, diet, and inadequate sunlight exposure.
Kidney, Liver, and Transplantation
120. Association Between Vitamin D Deficiency and Chronic Kidney Disease Progression | Multiple authors | Systematic Review and Meta-analysis | 2026
Finds an observational association between lower vitamin D concentrations and CKD progression, while grading the certainty of much of the evidence as low or very low.
121. Impact of Vitamin D Supplementation on the Outcomes of Kidney Transplant Recipients | Bin-Qi Yang et al. | BMC Nephrology | 2026
Evaluates randomized and clinical evidence concerning vitamin D treatment following kidney transplantation and its effects on transplant-related outcomes.
122. Role of Vitamin D Supplementation in Chronic Liver Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials | Petrana Martinekova et al. | Nutrition Reviews | 2025
Reviews trials of supplementation in chronic liver disease and finds that although deficiency is common, evidence for substantial improvement in major liver outcomes remains uncertain.
123. Prevalence of Vitamin D Deficiency and Impact on Clinical Outcomes After Kidney Transplantation | Saifu Yin et al. | Nutrition Reviews | 2022
Finds vitamin D deficiency common after kidney transplantation and examines associations with mortality, rejection, infection, and graft function.
124. The Role of Vitamin D in Kidney Transplantation Outcomes | Multiple authors | Systematic Review | 2022
Reviews evidence linking vitamin D status with graft function, rejection, infections, mortality, and other outcomes among kidney transplant recipients.
125. Vitamin D Supplementation for Patients With Chronic Kidney Disease | Marilena Christodoulou, Terence J. Aspray, Inez Schoenmakers | Calcified Tissue International | 2021
Reviews supplementation trials and clinical guidelines addressing vitamin D deficiency, secondary hyperparathyroidism, and mineral-bone abnormalities in chronic kidney disease.
126. Vitamin D Deficiency in Chronic Kidney Disease: Recent Evidence and Controversies [PMID/PMC 6121405 | Multiple authors | International Journal of Molecular Sciences | 2018]
Reviews the high prevalence and complex causes of vitamin D deficiency in chronic kidney disease and its relationship with mineral metabolism and clinical outcomes.
127. Vitamin D Supplementation and Non-Alcoholic Fatty Liver Disease | Multiple authors | Critical and Systematic Review | 2017
Reviews clinical trials investigating whether correcting vitamin D deficiency improves hepatic steatosis, liver enzymes, inflammation, or insulin resistance in fatty liver disease.
128. Vitamin D Deficiency in Chronic Liver Disease | Multiple authors | World Journal of Hepatology | 2014
Reviews vitamin D metabolism in liver disease and relationships with chronic hepatitis, fatty liver disease, inflammation, and disease severity.
129. Vitamin D Supplementation in Chronic Kidney Disease: A Systematic Review and Meta-analysis | Multiple authors | Clinical Journal of the American Society of Nephrology | 2011
Evaluates observational studies and randomized trials involving ergocalciferol and cholecalciferol among patients with chronic kidney disease.
Cardiovascular Disease, Cancer, and Mortality
130. Association Between Vitamin D Deficiency and the Incidence of Atrial Fibrillation | Angelica Cersosimo et al. | Biomedicines | 2026
Meta-analysis of prospective studies finds lower circulating vitamin D modestly associated with greater incidence of atrial fibrillation.
131. Effect of Vitamin D Supplementation on Cardiovascular Outcomes: An Updated Meta-analysis of RCTs | Multiple authors | Systematic review and meta-analysis | 2024
Finds vitamin D supplementation does not significantly reduce major cardiovascular events, myocardial infarction, heart failure, cardiovascular mortality, or overall mortality.
132. Cardiovascular and Cerebrovascular Outcomes With Vitamin D Supplementation | Multiple authors | Current Problems in Cardiology | 2023
Reviews randomized evidence concerning cardiovascular and cerebrovascular outcomes and finds little evidence of major preventive benefit.
133. Vitamin D Supplementation and Its Impact on Mortality and Cardiovascular Outcomes | Multiple authors | Systematic review of 80 randomized trials | 2023
Large evidence synthesis assesses vitamin D supplementation for all-cause mortality, cardiovascular mortality, myocardial infarction, stroke, and heart failure.
134. Efficacy of Vitamin D3 Supplementation on Cancer Mortality | Multiple authors | Systematic review and individual-patient-data meta-analysis | 2023
Finds daily vitamin D supplementation may be associated with lower cancer mortality, whereas intermittent large bolus dosing shows less evidence of benefit.
135. Vitamin D Supplementation for Prevention of Total Cancer Incidence and Mortality | Multiple authors | Heliyon | 2022
Updated randomized-trial meta-analysis finds no reduction in total cancer incidence and uncertain evidence for cancer mortality in generally vitamin-D-replete populations.
136. Association Between Vitamin D Supplementation and Cancer Incidence and Mortality | Multiple authors | Critical Reviews in Food Science and Nutrition | 2022
Trial-sequential meta-analysis finds supplementation does not reduce overall cancer incidence but reports evidence suggesting lower cancer mortality.
137. Vitamin D Supplementation and Cardiovascular Disease Risks in More Than 83,000 Individuals | Multiple authors | JAMA Cardiology | 2019
Meta-analysis of 21 randomized trials finds no reduction in major cardiovascular events, myocardial infarction, stroke, or cardiovascular mortality.
138. Vitamin D Supplementation and Total Cancer Incidence and Mortality | Multiple authors | Annals of Oncology | 2019
Finds no effect on total cancer incidence but reports a modest reduction in cancer mortality across randomized trials.
139. Vitamin D Deficiency and Mortality Risk in the General Population | Multiple authors | American Journal of Clinical Nutrition | 2012
Prospective cohort meta-analysis reports an inverse observational relationship between circulating vitamin D and all-cause mortality.
Infection, Respiratory Disease, Critical Illness, and Burns
140. Vitamin D Supplementation for Managing COVID-19 in Patients With Vitamin D Deficiency | Lemei Zhu et al. | BMJ Open | 2025
Meta-analysis of randomized trials specifically examines vitamin D treatment in COVID-19 patients who were vitamin-D deficient.
141. Vitamin D Deficiency and Clinical Outcomes in Adult Burn Patients | Multiple authors | Systematic Review and Meta-analysis | 2025
Finds deficiency associated observationally with increased systemic infections and longer hospital or intensive-care stays following major burns.
142. Vitamin D Deficiency in Patients With Cystic Fibrosis: A Systematic Review and Meta-analysis | Multiple authors | Journal of Health, Population and Nutrition | 2024
Finds lower vitamin D levels and substantial deficiency prevalence among both pediatric and adult patients with cystic fibrosis.
143. Does Vitamin D Improve All-Cause Mortality in Critically Ill Adults? | Multiple authors | Systematic review and meta-analysis | 2023
Reviews randomized trials in intensive-care patients and finds no convincing overall mortality reduction from vitamin D supplementation.
144. Administration of Vitamin D and Its Metabolites in Critically Ill Adult Patients | Multiple authors | Critical Care | 2022
Updated randomized-trial meta-analysis evaluates mortality, length of stay, ventilation, and other outcomes among critically ill adults.
145. Association of Vitamin D Deficiency With COVID-19 Infection Severity | Multiple authors | Systematic review and meta-analysis | 2021
Reports observational associations between deficiency and higher mortality, hospitalization, and severe COVID-19, while acknowledging limitations of nonrandomized evidence.
146. The Role of Vitamin D Deficiency on COVID-19 | Multiple authors | Systematic review and meta-analysis | 2021
Reviews observational evidence linking lower vitamin D status with COVID-19 infection and severity, with less consistent findings for mortality.
147. Association of Vitamin D Deficiency With Pulmonary Tuberculosis | Multiple authors | Systematic review and meta-analysis | 2021
Finds substantially greater odds of vitamin D deficiency among patients with pulmonary tuberculosis than among healthy controls.
148. The Effect of Vitamin D Supplementation on Clinical Outcomes for Critically Ill Patients | Multiple authors | Frontiers in Nutrition | 2021
Meta-analysis finds no clear overall mortality benefit, although some secondary outcomes and subgroups suggested possible effects.
149. Vitamin D Supplementation to Prevent Acute Respiratory Infections | Adrian R. Martineau et al. | Health Technology Assessment | 2019
Individual-participant-data meta-analysis finds supplementation can modestly reduce acute respiratory infections, with larger benefits among severely deficient participants receiving regular dosing.
150. Targeting Vitamin D Deficiency to Limit Exacerbations in Respiratory Diseases | Multiple authors | Review Article | 2019
Reviews whether correcting deficiency could reduce exacerbations in asthma, COPD, and cystic fibrosis.
151. Vitamin D Deficiency: What Does It Mean for Chronic Obstructive Pulmonary Disease? | Nurdan Kokturk et al. | Clinical Respiratory Journal | 2018
Reviews the high prevalence of vitamin D deficiency in COPD and possible relationships with lung function, exacerbations, immunity, and disease progression.
152. Vitamin D Status and Its Influence on Outcomes Following Major Burn Injury and Critical Illness | Multiple authors | Burns & Trauma Review | 2018
Discusses how major burns and critical illness can alter vitamin D metabolism and examines associations with inflammation, sepsis, organ dysfunction, and recovery.
153. Vitamin D Supplementation in the Critically Ill | Multiple authors | Clinical Nutrition | 2017
Reviews randomized trials and finds insufficient evidence that high-dose supplementation improves mortality or other major ICU outcomes.
154. Vitamin D and Asthma in Children: A Systematic Review and Meta-analysis of Observational Studies | Multiple authors | Lung India | 2017
Finds vitamin D deficiency common among children with asthma and examines associations with asthma control and lung function.
155. A Review of Vitamin D Effects on Common Respiratory Diseases | Multiple authors | Advanced Pharmaceutical Bulletin | 2016
Reviews evidence concerning vitamin D deficiency in asthma, COPD, and tuberculosis and potential immunological mechanisms.
156. Vitamin D Deficiency as a Risk Factor for Infection, Sepsis and Mortality in the Critically Ill | Multiple authors | Critical Care | 2014
Observational meta-analysis finds deficiency associated with infection, sepsis, and mortality, while emphasizing that association does not demonstrate treatment benefit.
157. Vitamin D With Asthma and COPD: Not a False Hope? | L. L. Zhang, J. Gong, C. T. Liu | Genetics and Molecular Research | 2014
Systematic review and meta-analysis examines low vitamin D status in asthma and COPD and associations with pulmonary function.
158. The Role of Vitamin D in Chronic Obstructive Pulmonary Disease, Asthma and Other Respiratory Diseases | Multiple authors | Archivos de Bronconeumología | 2014
Reviews epidemiological evidence connecting low vitamin D with respiratory disorders while emphasizing the difficulty of establishing causation.
Neurological, Psychiatric, Epilepsy, and Pain Disorders
159. The Impact of Vitamin D Deficiency on Depression: A Systematic Review [Cambridge Core | M. F. Zeilstra et al. | European Psychiatry | 2026]
Reviews evidence linking low vitamin D status with depressive symptoms and discusses immune, neurological, and behavioral mechanisms that might contribute.
160. The Role of Vitamin D Deficiency in Psychiatric Disorders | Richa | Australasian Psychiatry | 2026
Systematic review evaluates vitamin D deficiency in depression and schizophrenia and discusses associations with symptom severity and biological markers.
161. Vitamin D Deficiency and Multiple Sclerosis Relapse | Multiple authors | Meta-analysis | 2026
Examines randomized trials of vitamin D in multiple sclerosis and evaluates serum levels, annualized relapse rates, and disability measures.
162. Vitamin D Deficiency and Supplementation in Migraine | Multiple authors | Scoping review | 2025
Reviews observational studies and clinical trials assessing vitamin D deficiency, migraine frequency, disability, and responses to supplementation.
163. The Association Between Vitamin D Deficiency and Multiple Sclerosis | Multiple authors | Multiple Sclerosis and Related Disorders | 2024
Updated systematic review finds vitamin D deficiency associated with greater odds of multiple sclerosis but does not establish that supplementation prevents disease.
164. Association of Vitamin D Levels With Risk of Cognitive Impairment and Dementia | Multiple authors | Systematic review and meta-analysis | 2024
Prospective evidence links vitamin D deficiency with elevated risks of cognitive impairment, dementia, and Alzheimer's disease.
165. Vitamin D Content and Prevalence of Vitamin D Deficiency in Patients With Epilepsy | Multiple authors | Systematic Review and Meta-analysis | 2024
Reviews 68 studies and finds a high prevalence of vitamin D deficiency among people with epilepsy, including those treated with antiseizure medications.
166. Effects of Vitamin D on Migraine: A Meta-analysis | Saibal Das et al. | Neurology India | 2023
Finds lower vitamin D concentrations among migraine patients and suggests supplementation may reduce attack frequency, though evidence quality remains limited.
167. Vitamin D Deficiency and Depressive Symptoms: Meta-analysis of Studies | Multiple authors | Psychiatric research review | 2023
Finds a statistical association between deficiency and depression while emphasizing uncertainty about causality and biological direction.
168. Vitamin D Deficiency in Pediatric Patients Using Antiepileptic Drugs | Multiple authors | Jornal de Pediatria | 2020
Meta-analysis finds vitamin D deficiency common among children receiving antiepileptic medications, including drugs that induce hepatic cytochrome P450 enzymes.
169. Vitamin D Deficiency and Schizophrenia in Adults | Jia-Lian Zhu et al. | Psychiatry Research | 2020
Meta-analysis finds people with schizophrenia have lower vitamin D concentrations and higher rates of deficiency than controls.
170. Vitamin D Deficiency as a Risk Factor for Dementia and Alzheimer's Disease | Multiple authors | BMC Neurology | 2019
Meta-analysis of prospective and cross-sectional evidence finds deficiency associated with increased dementia and Alzheimer's disease risk.
171. Vitamin D Status and Risk of Dementia and Alzheimer's Disease: Dose-Response Meta-analysis | Multiple authors | Neuroscience review | 2018
Examines dose-response relationships and reports greater dementia risk at low circulating vitamin D concentrations.
172. The Efficacy of Vitamin D in Multiple Sclerosis | Chao Zheng et al. | Multiple Sclerosis and Related Disorders | 2018
Meta-analysis assesses supplementation trials in multiple sclerosis and evaluates clinical and neurological outcomes.
173. Vitamin D for the Treatment of Multiple Sclerosis | Multiple authors | Journal of Neurology | 2018
Meta-analysis of clinical trials finds suggestive but generally nonsignificant evidence for vitamin D as a therapeutic adjunct in relapsing-remitting MS.
174. The Association Between Vitamin D Concentration and Pain | Multiple authors | British Journal of Nutrition | 2018
Meta-analysis of observational studies finds lower vitamin D concentrations among people with arthritis, muscle pain, and chronic widespread pain.
175. Epilepsy and Vitamin D: A Comprehensive Review of Current Knowledge | Seyed Amir Miratashi Yazdi et al. | Reviews in the Neurosciences | 2017
Reviews vitamin D metabolism in epilepsy, neurological mechanisms, antiepileptic medications, bone health, and supplementation.
176. Does Vitamin D Supplementation Alleviate Chronic Nonspecific Musculoskeletal Pain? | M. Gaikwad et al. | Clinical Rheumatology | 2017
Systematic review of randomized trials finds little evidence that supplementation meaningfully reduces chronic nonspecific musculoskeletal pain.
177. Vitamin D Status and Parkinson's Disease | Zheng Lv et al. | Neurological Sciences | 2014
Systematic review finds Parkinson's patients have lower vitamin D levels and greater prevalence of deficiency than control populations.
178. Vitamin D Deficiency and Depression in Adults | Rebecca E. S. Anglin et al. | British Journal of Psychiatry | 2013
Meta-analysis finds lower vitamin D concentrations among people with depression but emphasizes the need for randomized trials to determine causality.
179. Vitamin D Deficiency, Cognitive Impairment and Dementia | Thorleif Etgen et al. | Dementia and Geriatric Cognitive Disorders | 2012
Systematic review and meta-analysis finds observational associations between low vitamin D and impaired cognition or dementia.
Autoimmune, Endocrine, Dermatological, and Oral Disorders
180. Vitamin D Deficiency and Oral Health: A Systematic Review of Literature | Multiple authors | Systematic review | 2025
Reviews associations between vitamin D deficiency and periodontal disease, dental caries, mineralization defects, and other oral conditions.
181. Vitamin D Deficiency in Non-scarring and Scarring Alopecias | Multiple authors | Systematic review and meta-analysis | 2024
Finds vitamin D deficiency particularly common in alopecia areata and female-pattern hair loss, while evidence for other alopecias is less consistent.
182. The Impact of Vitamin D Deficiency on Caries, Periodontitis, and Oral Cancer | Multiple authors | Saudi Dental Journal | 2024
Reviews evidence suggesting a stronger relationship between deficiency and periodontitis than with dental caries or oral cancer.
183. Effect of Vitamin D on Inflammatory and Clinical Outcomes in Rheumatoid Arthritis | Hagir Al-Saoodi et al. | Nutrition Reviews | 2024
Meta-analysis of randomized trials finds supplementation does not consistently improve inflammatory markers or rheumatoid arthritis disease activity.
184. Vitamin D Status and Risk of Rheumatoid Arthritis | Multiple authors | Systematic Review and Meta-analysis | 2023
Prospective evidence does not clearly support low vitamin D as a cause of future rheumatoid arthritis despite frequent deficiency in established disease.
185. Comparing Vitamin D Levels Between Patients With Psoriasis and Healthy Individuals | Multiple authors | Systematic Review and Meta-analysis | 2023
Finds patients with psoriasis have substantially higher odds of low serum vitamin D than control populations.
186. Association Between Vitamin D Deficiency and Autoimmune Thyroid Disorder | Multiple authors | Systematic Review | 2022
Reviews studies comparing vitamin D status in Hashimoto's thyroiditis, Graves' disease, and healthy control populations.
187. Vitamin D Implications and Effect of Supplementation in Endocrine Disorders | Multiple authors | Medicina | 2022
Reviews vitamin D deficiency and supplementation in autoimmune thyroid disease, diabetes mellitus, and obesity.
188. Serum Vitamin D Level and Vitamin D Supplementation in Children With Atopic Dermatitis | Multiple authors | Systematic Review and Meta-analysis | 2022
Finds children with atopic dermatitis have increased odds of deficiency and evaluates supplementation effects on SCORAD and EASI severity scores.
189. Vitamin D Status and Efficacy of Vitamin D Supplementation in Acne Patients | Multiple authors | Journal of Cosmetic Dermatology | 2021
Systematic review finds lower circulating vitamin D among acne patients and evaluates preliminary evidence for supplementation.
190. Vitamin D and Periodontitis: A Systematic Review and Meta-analysis | Multiple authors | Journal of Dentistry | 2020
Finds lower circulating vitamin D concentrations among chronic periodontitis patients and examines supplementation as an adjunct to periodontal therapy.
191. Vitamin D and Autoimmune Thyroid Diseases | Multiple authors | Review | 2020
Discusses vitamin D receptors, immune regulation, Hashimoto's thyroiditis, Graves' disease, and supplementation studies.
192. Vitamin D Deficiency and Effects of Vitamin D Supplementation in Atopic Dermatitis | Sonal R. Hattangdi-Haridas et al. | Nutrients | 2019
Meta-analysis finds lower vitamin D levels among patients with atopic dermatitis and examines changes in disease severity following supplementation.
193. Association Between Vitamin D Level and Systemic Lupus Erythematosus | Sang-Cheol Bae and Young Ho Lee | Cellular and Molecular Biology | 2018
Meta-analysis finds lower vitamin D concentrations and a greater prevalence of deficiency among patients with systemic lupus erythematosus.
194. Vitamin D Deficiency in Patients With Alopecia Areata | Tsung-Yu Tsai and Yu-Chen Huang | Journal of the American Academy of Dermatology | 2018
Meta-analysis reports substantially greater vitamin D deficiency among people with alopecia areata compared with controls.
195. Vitamin D Level in Rheumatoid Arthritis and Its Correlation With Disease Activity | Multiple authors | Meta-analysis | 2016
Finds lower vitamin D levels and more frequent deficiency among patients with rheumatoid arthritis and examines correlations with disease activity.
196. Low 25-Hydroxyvitamin D Levels Are Associated With Vitiligo | Sikarin Upala and Anawin Sanguankeo | Photodermatology, Photoimmunology & Photomedicine | 2016
Meta-analysis finds lower vitamin D concentrations among patients with vitiligo but cautions that observational evidence cannot establish causation.
197. The Clinical Significance of Vitamin D in Systemic Lupus Erythematosus | Multiple authors | PLOS ONE | 2013
Systematic review examines the high prevalence of deficiency in lupus and possible relationships with disease activity and clinical manifestations.
