UV Exposure and Health
- NOTOC**
UV Exposure and Health
Ultraviolet (UV) radiation is an invisible form of electromagnetic radiation produced primarily by the Sun, although humans may also be exposed to artificial sources such as tanning devices, welding equipment, and medical phototherapy systems. The health effects of UV radiation are complex because sunlight can produce both harmful and potentially beneficial biological responses.
UVA and UVB radiation are the wavelengths of greatest relevance to human health. UVA penetrates more deeply into the skin and contributes substantially to oxidative stress, pigmentation, photoaging, and some forms of DNA damage. UVB is more energetic and is particularly important in sunburn, direct DNA damage, skin carcinogenesis, and production of vitamin D in the skin. UVC is largely absorbed by the atmosphere under normal environmental conditions.
The best-established health risks of excessive ultraviolet exposure include sunburn, premature skin aging, several forms of skin cancer, eye damage, and alterations in immune function. At the same time, UVB exposure initiates vitamin D production, and research has identified additional possible pathways through which sunlight may influence cardiovascular, metabolic, and immune health. These competing effects make the relationship between sunlight and health more complicated than a simple distinction between beneficial and harmful exposure.
DNA Damage and Skin Cancer
One of the most important biological consequences of ultraviolet radiation is damage to cellular DNA. UVB can produce cyclobutane pyrimidine dimers and other photoproducts that distort DNA and interfere with normal replication and transcription. UVA can also contribute to DNA injury, particularly through oxidative mechanisms.
Human cells possess nucleotide-excision repair and other systems that identify and remove ultraviolet-induced DNA lesions. When damage is extensive, repeatedly produced, or inadequately repaired, mutations may accumulate.
Research on the tumor-suppressor gene p53 provided some of the earliest molecular evidence directly connecting sunlight exposure with skin cancer. Characteristic UV-associated mutations have been identified in squamous cell carcinomas and precancerous actinic lesions.
The importance of DNA repair is particularly evident in xeroderma pigmentosum, a genetic disorder involving defective repair of ultraviolet-induced DNA damage. People with the condition have extreme sensitivity to sunlight and an exceptionally high risk of developing skin cancers. Research involving xeroderma pigmentosum has contributed significantly to understanding the relationship between ultraviolet radiation, DNA repair, mutation, and carcinogenesis.
Ultraviolet radiation is associated with basal cell carcinoma, squamous cell carcinoma, and melanoma. Patterns of exposure may also matter. Research indicates that intermittent intense exposure and episodes of sunburn can be particularly important in melanoma risk, while cumulative occupational exposure is associated with several other forms of chronic solar damage.
Pigmentation, Tanning, and Photoaging
Human skin pigmentation provides a degree of natural photoprotection. Melanin absorbs and scatters ultraviolet radiation and can reduce the amount of damaging radiation reaching vulnerable cellular structures.
Differences in constitutive pigmentation therefore influence susceptibility to sunburn and some forms of UV-associated skin damage. However, darker pigmentation does not provide complete protection, and people of all skin tones can experience ultraviolet injury.
Exposure to ultraviolet radiation stimulates tanning and other pigmentation responses. UV exposure can also contribute to conditions such as melasma and post-inflammatory hyperpigmentation. Research increasingly recognizes that visible light, in addition to UVA and UVB, can contribute to pigmentation changes in some individuals.
Chronic ultraviolet exposure is one of the major environmental causes of premature skin aging. UV-generated reactive oxygen species affect collagen, elastin, and other components of the extracellular matrix. Increased activity of matrix metalloproteinases contributes to collagen degradation, while abnormal elastic tissue can accumulate in chronically exposed skin.
The resulting process, commonly known as photoaging, can produce wrinkles, changes in skin texture, uneven pigmentation, loss of elasticity, and other characteristics associated with long-term sunlight exposure.
Some research has also identified a complex relationship between melanin and ultraviolet damage. Although melanin normally provides substantial protection, chemical reactions involving melanin after UV exposure may under certain circumstances continue producing DNA photoproducts even after exposure has ended.
Vitamin D and Potential Systemic Effects
One of the best-known beneficial biological consequences of UVB exposure is vitamin D synthesis. Ultraviolet radiation converts molecules in the skin into precursors that eventually become biologically active vitamin D.
Vitamin D is important for bone metabolism and many other physiological processes. This has led to continuing discussion about balancing adequate vitamin D status with protection against excessive ultraviolet exposure.
Research has also investigated effects of sunlight that may occur independently of vitamin D. UVA exposure can release nitric-oxide-related compounds stored in the skin. Experimental studies have shown that this process can dilate blood vessels and temporarily lower blood pressure.
Observational and experimental research has therefore examined possible relationships between sunlight, hypertension, cardiovascular disease, obesity, metabolic syndrome, and type 2 diabetes. Although several biological mechanisms are plausible, the available literature does not establish that deliberate additional UV exposure should be used as a general treatment for cardiovascular or metabolic disease.
Possible systemic effects must also be considered alongside the well-established carcinogenic consequences of ultraviolet radiation.
Immune Effects and Multiple Sclerosis
Ultraviolet radiation can alter both innate and adaptive immune responses. Some of these immunological effects contribute to reduced local immune surveillance in the skin and may play a role in carcinogenesis.
UV exposure may also alter interactions between human skin and its microbiome. Research is investigating whether microorganisms and their metabolites contribute to antioxidant defense, barrier repair, inflammatory regulation, and adaptation to solar radiation.
A separate body of research has examined the relationship among ultraviolet exposure, vitamin D, latitude, and multiple sclerosis. Geographic and epidemiological studies have identified associations between lower sunlight exposure and greater multiple-sclerosis risk in some populations.
Season of birth and maternal ultraviolet exposure during pregnancy have also been investigated. Some studies report relationships between low prenatal UV exposure and later multiple-sclerosis risk.
These findings have generated hypotheses involving both vitamin-D-dependent and vitamin-D-independent immune pathways. However, associations between sunlight and disease risk do not by themselves establish that increased UV exposure is an appropriate preventive treatment.
Photodermatoses and Abnormal Sunlight Responses
Some people experience abnormal reactions to relatively small amounts of ultraviolet or visible radiation. These disorders are collectively known as photodermatoses.
Polymorphic light eruption, solar urticaria, chronic actinic dermatitis, actinic prurigo, phototoxic reactions, photoallergic reactions, and several genetic or metabolic disorders can produce unusually severe responses to sunlight.
Solar urticaria can cause rapid itching, redness, and wheal formation after exposure to particular wavelengths. Rare cases can involve sunlight-induced angioedema.
Chronic actinic dermatitis produces persistent inflammatory skin reactions in individuals who may be extraordinarily sensitive to UVA, UVB, or visible light.
Erythropoietic protoporphyria is another photosensitive condition in which light exposure can cause severe skin pain. Specialized phototesting is sometimes used to identify triggering wavelengths and evaluate disease severity.
Diagnosis of photosensitive disorders may involve clinical history, laboratory evaluation, phototesting, and controlled exposure to specific wavelengths. Management can include avoidance, protective clothing, sunscreen, medication, desensitizing phototherapy, and treatment of underlying disease.
Therapeutic Uses of Ultraviolet Radiation
Although uncontrolled ultraviolet exposure can damage human tissue, carefully administered ultraviolet radiation is also an important medical treatment.
Narrowband UVB, broadband UVB, UVA, and psoralen plus UVA therapy have been used for numerous dermatologic diseases. Among the most extensively studied applications are psoriasis, vitiligo, atopic dermatitis, and early-stage cutaneous T-cell lymphoma.
Narrowband UVB has become particularly important because it can deliver therapeutically useful wavelengths while limiting some unnecessary exposure.
For vitiligo, repeated narrowband UVB treatments can stimulate repigmentation. Research has also investigated combining phototherapy with newer treatments, including Janus kinase inhibitors.
For psoriasis and atopic dermatitis, UV treatment can suppress abnormal inflammatory pathways and reduce disease activity.
Phototherapy may be administered in specialized medical facilities or, for selected patients, with properly prescribed home devices. Studies comparing home-based and office-based treatment suggest that home therapy can reduce treatment burden while providing clinically useful outcomes when appropriate medical supervision is maintained.
Medical phototherapy differs fundamentally from recreational tanning because treatment doses and wavelengths are selected for specific conditions and monitored according to clinical protocols.
Occupational and Environmental Exposure
Some occupations involve much greater ultraviolet exposure than the general population.
Outdoor workers can accumulate substantial solar UV doses over many years. Studies of occupational exposure have identified increased risks of chronic skin damage and some forms of skin cancer.
Welders face a different form of hazard. Welding arcs can produce intense artificial ultraviolet and blue-light radiation capable of damaging both skin and eyes within short periods if adequate protective equipment is not used.
Environmental conditions influence ultraviolet exposure as well. Atmospheric ozone absorbs substantial amounts of solar ultraviolet radiation. Changes in ozone concentrations can therefore affect the amount of UV reaching Earth's surface.
Research modeling ozone-depleting substances has demonstrated potential effects on future rates of skin cancer and cataracts.
Climate change may also alter patterns of ultraviolet exposure indirectly through temperature, cloud cover, air pollution, time spent outdoors, clothing practices, recreational behavior, and occupational conditions. The relationship is complex because climatic changes can influence both environmental UV levels and human behavior.
Eye and Lip Damage
Ultraviolet radiation affects tissues beyond ordinary skin surfaces.
Long-term sunlight exposure is associated with several forms of ocular damage. Occupational studies have found relationships between chronic solar radiation and pterygium, a growth of tissue extending from the conjunctiva toward the cornea.
Protective eyewear that blocks ultraviolet radiation can reduce ocular exposure, particularly among people who work outdoors for long periods.
The lips are also vulnerable to chronic sunlight. Actinic cheilitis is a persistent sun-related disorder that most commonly affects the lower lip. Because it can represent a potentially precancerous change, persistent lesions may require medical evaluation and treatment.
Sun Protection and Behavioral Interventions
Reducing excessive ultraviolet exposure is a major strategy for preventing skin cancer and other UV-related damage.
Protective approaches include seeking shade, wearing protective clothing and hats, using appropriate sunglasses, applying broad-spectrum sunscreen, and adjusting outdoor activities when ultraviolet radiation is particularly intense.
The UV Index was developed to communicate the expected intensity of ultraviolet radiation and help people determine when protective measures are especially important. Research indicates, however, that awareness of the UV Index does not always lead to improved protective behavior.
Educational programs in schools and workplaces have attempted to improve sunscreen use, clothing choices, shade seeking, and knowledge of UV hazards.
Digital technologies have created additional approaches to prevention. Smartphone applications can provide real-time ultraviolet information, reminders, personalized sun-protection recommendations, and feedback from wearable UV dosimeters.
Some randomized trials suggest that these interventions can improve selected protective behaviors, although no single strategy consistently changes all aspects of sun exposure.
Workplace programs are particularly important for outdoor workers because occupational exposure occurs repeatedly over long periods. Policies involving shade, scheduling, protective clothing, sunscreen access, education, and eye protection can reduce cumulative exposure.
Balancing Risks and Benefits
The health effects of sunlight cannot be evaluated solely by considering either its risks or its benefits.
Excessive ultraviolet exposure is an established cause of DNA damage, premature skin aging, skin cancer, and eye injury. These effects provide a strong basis for preventing unnecessary high-intensity and cumulative exposure.
At the same time, sunlight contributes to vitamin D synthesis and produces other measurable biological effects. Research into nitric oxide, cardiovascular function, immune regulation, metabolism, and systemic disease suggests that sunlight has physiological consequences extending beyond the skin.
The appropriate public-health challenge is therefore not complete avoidance of sunlight but reduction of harmful exposure while maintaining health through safer means. Vitamin D status, for example, can be supported through diet and supplementation when appropriate without requiring excessive ultraviolet exposure.
Medical phototherapy illustrates the same principle: ultraviolet radiation can be harmful when uncontrolled but therapeutically valuable when wavelength, dose, frequency, and clinical indication are carefully managed.
Conclusion
Ultraviolet radiation is a powerful environmental influence on human biology. Its effects range from immediate sunburn and pigmentation to long-term DNA mutation, photoaging, eye disease, and skin cancer.
Research has revealed increasingly detailed mechanisms through which UVA and UVB affect DNA repair, oxidative stress, pigmentation, immunity, blood vessels, skin microorganisms, and inflammatory pathways. Sunlight also contributes to vitamin D production and may influence cardiovascular and immune physiology through additional mechanisms.
Certain diseases cause abnormal sensitivity to ultraviolet or visible light, while controlled UV exposure has become an established therapeutic tool for conditions including psoriasis, vitiligo, atopic dermatitis, and cutaneous T-cell lymphoma.
The overall evidence supports a balanced approach. Unnecessary and intense ultraviolet exposure should be minimized, particularly sunburn and chronic occupational exposure, while recognizing that sunlight is also an important environmental component of human physiology. Effective protection combines education, shade, clothing, sunscreen, eye protection, occupational safeguards, and informed use of the UV Index.
Understanding both the beneficial and harmful effects of ultraviolet radiation provides a stronger foundation for individual decisions, clinical treatment, occupational protection, and public-health policy.
- TOC**
General UV Exposure and Human Health
1. Facts About Ultraviolet Radiation
[CDC ultraviolet-radiation facts | Centers for Disease Control and Prevention | CDC | 2026] Provides an overview of natural and artificial UV sources and explains the balance between vitamin D production and risks including sunburn, aging, eye disease, and skin cancer.
2. Ultraviolet Radiation
[CDC UV radiation overview | Centers for Disease Control and Prevention | CDC | 2026] Describes UVA, UVB, and UVC wavelengths, their penetration and environmental sources, and their beneficial and harmful effects on human health.
3. UV (Ultraviolet) Radiation and Cancer Risk
[American Cancer Society UV radiation page | American Cancer Society Medical and Editorial Content Team | American Cancer Society | 2026] Reviews how UV radiation damages cellular DNA and contributes to basal cell carcinoma, squamous cell carcinoma, melanoma, premature aging, and eye damage.
4. Radiation: The known health effects of ultraviolet radiation
[WHO UV radiation Q&A | World Health Organization | WHO | 2024] Explains differences between UVA and UVB and discusses sunburn, skin cancer, premature aging, eye injury, immune effects, and vitamin D production.
5. Ultraviolet Radiation Biological and Medical Implications
[PMID:38534742 | Tarek Al-Sadek and Nabiha Yusuf | Current Issues in Molecular Biology | 2024] Reviews the biological mechanisms, detrimental effects, medical applications, and potentially beneficial consequences of ultraviolet radiation.
6. Current insights and future perspectives of ultraviolet radiation exposure: Friends and foes to the skin and beyond the skin
[PMID:38428192 | Multiple authors | Environment International | 2024] Examines UV-induced inflammation, DNA damage, immunosuppression, photoaging, carcinogenesis, therapeutic uses, and possible systemic health effects.
7. Sunlight: Time for a Rethink?
[DOI:10.1016/j.jid.2023.12.027 | Multiple authors | Journal of Investigative Dermatology | 2024] Discusses the established carcinogenic effects of UV while reviewing evidence for possible cardiovascular, mortality, vitamin D, and nitric-oxide-related benefits of sunlight.
8. Cancer Risk Factors: Sunlight
[NCI sunlight risk page | National Cancer Institute | National Cancer Institute | 2023] Summarizes evidence linking sunlight, sunlamps, and tanning booths with skin damage and cancer and describes practical methods for reducing UV exposure.
9. Ultraviolet radiation
[WHO ultraviolet-radiation fact sheet | World Health Organization | WHO | 2022] Reviews the health effects of ultraviolet radiation, including skin cancers, eye damage, immune suppression, sunburn, photoaging, and the beneficial role of UVB in vitamin D synthesis.
10. Exposure to Ultraviolet Radiation in the Modulation of Human Diseases
[PMID:30125148 | Prue H. Hart and colleagues | Annual Review of Pathology | 2019] Reviews both adverse and potentially beneficial UV effects involving inflammatory skin disease, immunity, vitamin D, nitric oxide, autoimmune disorders, and cardiovascular health.
UV-Induced DNA Damage, Mutation and Repair
11. Transcription-Coupled Nucleotide Excision Repair and the Transcriptional Response to UV-Induced DNA Damage
[PMID:37040775 | Multiple authors | Annual Review of Biochemistry | 2023] Reviews how cells remove UV-induced lesions from actively transcribed genes and how DNA damage alters transcription, signaling, and genome stability.
12. Xeroderma pigmentosum: an updated review
[PMID:35520754 | Multiple authors | Drugs in Context | 2022] Reviews the clinical features, DNA-repair defects, extreme UV sensitivity, skin-cancer susceptibility, ocular disease, and management of xeroderma pigmentosum.
13. Mechanisms of UV-induced mutations and skin cancer
[PMID:34589668 | Multiple authors | DNA Repair | 2021] Reviews how cyclobutane pyrimidine dimers, mutation formation, DNA replication, and nucleotide-excision repair generate the characteristic UV mutational signatures found in skin cancers.
14. Expanding molecular roles of UV-DDB: Shining light on genome stability and cancer
[PMID:32739133 | Multiple authors | DNA Repair | 2020] Reviews the UV-damaged DNA-binding complex and its roles in recognizing ultraviolet lesions, organizing nucleotide-excision repair, chromatin regulation, and cancer prevention.
15. Focus on UV-Induced DNA Damage and Repair—Disease Relevance and Protective Strategies
[PMID:33019598 | Multiple authors | International Journal of Molecular Sciences | 2020] Summarizes ultraviolet-induced DNA lesions, repair pathways, oxidative damage, disease consequences, and possible strategies for reducing UV-related cellular injury.
16. Xeroderma Pigmentosa Group A (XPA), Nucleotide Excision Repair and Regulation by ATR in Response to Ultraviolet Irradiation
[PMID:29124689 | Multiple authors | Advances in Experimental Medicine and Biology | 2017] Examines the XPA protein, ATR signaling, nucleotide-excision repair, and the extreme ultraviolet sensitivity associated with xeroderma pigmentosum.
17. UV-induced Melanin Chemiexcitation: A New Mode of Melanoma Pathogenesis
[PMID:26951162 | Multiple authors | Tsinghua Science and Technology / review literature | 2016] Reviews evidence that melanin can have a dual role by protecting against incoming UV while under some conditions contributing to delayed DNA photoproduct formation.
18. Photochemistry. Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure
[PMID:25700512 | Sanjay Premi et al. | Science | 2015] Reports that melanin-related chemical excitation can continue producing mutagenic cyclobutane pyrimidine dimers for hours after ultraviolet exposure has ended.
19. UV radiation and the skin
[PMID:23749111 | John D'Orazio et al. | International Journal of Molecular Sciences | 2013] Provides a broad review of UV wavelengths, pigmentation, DNA damage, skin cancer, vitamin D production, tanning responses, and molecular defenses against ultraviolet radiation.
20. UV-induced DNA damage and repair: a review
[PMID:12661961 | Rajeshwar P. Sinha and Donat P. Häder | Photochemical & Photobiological Sciences | 2002] Reviews cyclobutane pyrimidine dimers, 6-4 photoproducts, oxidative DNA injury, nucleotide-excision repair, photoreactivation, and other cellular responses to ultraviolet damage.
21. Common pathways for ultraviolet skin carcinogenesis in the repair and replication defective groups of xeroderma pigmentosum
[PMID:10699759 | Multiple authors | Journal of Dermatological Science | 2000] Compares DNA-repair and replication defects among xeroderma pigmentosum groups and their relationship to UV sensitivity and cutaneous malignancy.
22. Xeroderma pigmentosum and the role of UV-induced DNA damage in skin cancer
[PMID:10200950 | Multiple authors | Molecular Medicine Today | 1999] Uses xeroderma pigmentosum as a model for understanding how failure to repair UV-induced DNA lesions dramatically increases human skin-cancer risk.
23. Sunburn and p53 in the onset of skin cancer
[PMID:7997263 | A. Ziegler et al. | Nature | 1994] Shows that UV-associated p53 mutations arise early in actinic keratoses and explains how UV can function both as a tumor initiator and promoter during skin-cancer development.
24. A role for sunlight in skin cancer: UV-induced p53 mutations in squamous cell carcinoma
[PMID:1946433 | D. E. Brash et al. | Proceedings of the National Academy of Sciences | 1991] Demonstrates characteristic UV-associated mutations in the p53 tumor-suppressor gene in human squamous cell carcinomas, providing molecular evidence connecting sunlight exposure with skin carcinogenesis.
25. Evidence that xeroderma pigmentosum cells do not perform the first step in the repair of ultraviolet damage to their DNA
[PMID:5264135 | R. B. Setlow et al. | Proceedings of the National Academy of Sciences | 1969] Landmark experimental work showing defective removal of UV-induced pyrimidine dimers in xeroderma pigmentosum cells.
Pigmentation, Photoaging and the Skin's Response to UV
26. International modified Delphi consensus statement on visible light photoprotection: Effects, measurement, and recommendations
[PMID:42101389 | Multiple authors | Journal of Investigative Dermatology | 2026] Provides expert consensus on visible-light-induced pigmentation, populations most likely to benefit from protection, and methods for evaluating visible-light photoprotection.
27. Photoaging: Current Concepts on Molecular Mechanisms, Prevention, and Treatment
[PMID:40072791 | Maria V. Kaltchenko and Anna L. Chien | American Journal of Clinical Dermatology | 2025] Reviews contemporary understanding of UV-, visible-light-, and infrared-associated photoaging and available preventive and therapeutic approaches.
28. Mechanisms of ultraviolet-induced melasma formation: A review
[PMID:35946331 | Jian Yang, Jinrong Zeng and Jianyun Lu | Journal of Dermatology | 2022] Reviews how ultraviolet radiation contributes to melasma through melanogenesis, oxidative stress, barrier abnormalities, inflammatory signaling, and altered gene expression.
29. Photoprotection of the Skin from Visible Light-Induced Pigmentation: Current Testing Methods and Proposed Harmonization
[PMID:34112516 | Henry W. Lim et al. | Journal of Investigative Dermatology | 2021] Examines pigmentation induced by longer-wavelength sunlight and proposes methods for measuring protection beyond conventional UVB-focused sunscreen testing.
30. Photoprotection and Skin Pigmentation: Melanin-Related Molecules and Some Other New Agents Obtained from Natural Sources
[PMID:32230973 | Multiple authors | Molecules | 2020] Reviews melanin, oxidative stress, flavonoids, marine compounds, and other natural substances being investigated for ultraviolet photoprotection.
31. The Role of Sunscreen in Melasma and Postinflammatory Hyperpigmentation
[PMID:32029932 | Multiple authors | Indian Journal of Dermatology | 2020] Reviews evidence that broad-spectrum protection against UVA, UVB, and visible light can help control melasma and postinflammatory hyperpigmentation.
32. Elastin structure and its involvement in skin photoageing
[PMID:27731897 | Multiple authors | International Journal of Cosmetic Science | 2017] Examines solar elastosis, alterations in elastin synthesis and degradation, and the loss of normal elastic-fiber organization in chronically sun-exposed skin.
33. Oxidation events and skin aging
[PMID:25653189 | A. Kammeyer and R. M. Luiten | Ageing Research Reviews | 2015] Reviews UV-generated reactive oxygen and nitrogen species, collagen degradation, oxidative damage, and their contribution to extrinsic skin aging.
34. Regulation of human skin pigmentation and responses to ultraviolet radiation
[PMID:17250543 | Yoshinori Miyamura et al. | Pigment Cell Research | 2007] Reviews constitutive pigmentation, tanning, melanocyte biology, DNA damage, and differences in UV susceptibility between lighter and darker skin.
35. Photoaging: mechanisms and repair
[PMID:16781287 | Jessica H. Rabe et al. | Journal of the American Academy of Dermatology | 2006] Reviews cellular and extracellular mechanisms of photoaging and approaches for preventing or repairing chronic ultraviolet-associated skin damage.
36. Photoprotective properties of skin melanin
[PMID:11966725 | Jean-Paul Ortonne | British Journal of Dermatology | 2002] Examines the different physical and chemical properties of human melanins and their contribution to natural protection against ultraviolet radiation.
37. Pathophysiology of premature skin aging induced by ultraviolet light
[PMID:9358139 | G. J. Fisher et al. | New England Journal of Medicine | 1997] Demonstrates how UV exposure increases matrix metalloproteinases and collagen degradation, providing a molecular explanation for wrinkle formation and photoaging.
38. Photoprotection by melanin
[PMID:1907647 | N. Kollias et al. | Journal of Photochemistry and Photobiology B | 1991] Reviews how epidermal melanin absorbs and scatters ultraviolet radiation and how pigmentation modifies erythema and skin-cancer susceptibility.
UV Exposure, Immunity and the Skin Microbiome
39. The cutaneous microbiome as a dynamic photoprotective interface against solar radiation
[PMID:41870852 | Multiple authors | 2026] Proposes that resident skin microbes and their metabolites may contribute to antioxidant defense, immune regulation, barrier repair, and adaptation to chronic solar exposure.
40. A narrative review of the impact of ultraviolet radiation and sunscreen on the skin microbiome
[PMID:38288770 | Garett J. Grant, Indermeet Kohli and Tasneem F. Mohammad | Photodermatology, Photoimmunology & Photomedicine | 2024] Reviews how ultraviolet radiation and sunscreen ingredients may alter skin microorganisms, microbial metabolites, inflammation, and barrier function.
41. Exploring associations between skin, the dermal microbiome, and ultraviolet radiation: advancing possibilities for next-generation sunscreens
[PMID:41853364 | Matthew L. Smith et al. | Frontiers in Microbiomes | 2023] Explores interactions among UV radiation, sunscreen, host skin cells, and resident microorganisms and considers microbiome-conscious approaches to future photoprotection.
42. Eco-evolutionary impact of ultraviolet radiation exposure on microorganisms, with a special focus on our skin microbiome
[PMID:35483310 | Multiple authors | Microbiological Research | 2022] Reviews direct microbial UV injury, immunomodulation, skin-gut interactions, vitamin D, and potential microbial approaches to photoprotection.
43. The Skin Microbiome: Is It Affected by UV-induced Immune Suppression?
[PMID:27559331 | Multiple authors | Frontiers in Microbiology | 2016] Explores how UV-induced changes in innate and adaptive immunity may alter the skin microbiome and how microorganisms might influence responses to sunlight.
Cardiovascular and Metabolic Effects of Sunlight and UV
44. Systemic effects of sunlight: 10-year review of cardiovascular, infection and cancer outcomes
[PMID:42003711 | Multiple authors | Journal of the European Academy of Dermatology and Venereology | 2026] Reviews recent epidemiological research on sunlight and UV exposure in relation to cardiovascular disease, infections, internal cancers, mortality, and competing health risks.
45. Effects of ultraviolet light exposure on blood pressure: a systematic review
[PMID:42606691 | Multiple authors | 2026] Systematically evaluates human studies examining whether ultraviolet exposure alters blood pressure and assesses nitric-oxide and vitamin-D-related mechanisms.
46. Impact of ultraviolet radiation on cardiovascular and metabolic disorders: The role of nitric oxide and vitamin D
[PMID:37731181 | Qing-Ling Quan et al. | Photodermatology, Photoimmunology & Photomedicine | 2023] Reviews experimental and human evidence concerning UV exposure, hypertension, obesity, diabetes, metabolic syndrome, nitric oxide, and vitamin D.
47. The effect of daily UVA phototherapy for 2 weeks on clinic and 24-h blood pressure in individuals with mild hypertension
[PMID:35931819 | Multiple authors | Journal of Human Hypertension | 2022] Tests repeated low-dose UVA exposure in people with mild hypertension and examines whether acute UV-related vasodilation translates into sustained blood-pressure effects.
48. Does Incident Solar Ultraviolet Radiation Lower Blood Pressure?
[PMID:32106744 | Multiple authors | Journal of the American Heart Association | 2020] Large observational analysis of dialysis patients finds an inverse association between environmental UVA/UVB levels and systolic blood pressure after accounting for temperature.
49. Association of sun and UV exposure with blood pressure and cardiovascular disease: A systematic review
[PMID:30412763 | Multiple authors | Journal of Steroid Biochemistry and Molecular Biology | 2019] Reviews human studies investigating sunlight, ultraviolet exposure, blood pressure, cardiovascular outcomes, vitamin D, and possible vitamin-D-independent pathways.
50. Ultraviolet radiation, vitamin D and the development of obesity, metabolic syndrome and type-2 diabetes
[PMID:28009891 | Multiple authors | Photochemical & Photobiological Sciences | 2017] Reviews preclinical and human evidence connecting sunlight and UV exposure with obesity and cardiometabolic disease while emphasizing major uncertainties in causation.
51. Associations of blood pressure, sunlight, and vitamin D in community-dwelling adults
[PMID:27379541 | Multiple authors | Journal of Hypertension | 2016] Examines relationships among geographic solar radiation, circulating vitamin D, and blood pressure in more than one thousand adults.
52. Sun Exposure and Its Effects on Human Health: Mechanisms through Which Sun Exposure Could Reduce the Risk of Developing Obesity and Cardiometabolic Dysfunction
[PMID:27727191 | Shelley Gorman et al. | International Journal of Environmental Research and Public Health | 2016] Explores nitric oxide, vitamin D, inflammation, metabolism, and other mechanisms through which UV exposure could influence cardiometabolic health.
53. Risks and benefits of UV radiation in older people: More of a friend than a foe?
[PMID:26049767 | Multiple authors | Maturitas | 2015] Evaluates skin-cancer risks alongside vitamin D, nitric oxide, skeletal health, cardiovascular outcomes, and overall health considerations in older adults.
54. UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase
[PMID:24445737 | Donald Liu et al. | Journal of Investigative Dermatology | 2014] Randomized human experiments show that UVA can mobilize pre-existing nitric oxide stores in skin, increase blood flow, and temporarily lower blood pressure.
55. An unexpected role: UVA-induced release of nitric oxide from skin may have unexpected health benefits
[PMID:24924758 | Gary M. Halliday and Scott N. Byrne | Journal of Investigative Dermatology | 2014] Discusses the hypothesis that UVA-driven nitric oxide release from skin may contribute to systemic cardiovascular effects independently of vitamin D.
56. Whole body UVA irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous photolabile nitric oxide derivates
[PMID:19797169 | Multiple authors | Circulation Research | 2009] Reports that UVA exposure releases nitric-oxide-related compounds from human skin and produces a temporary reduction in blood pressure.
UV Exposure, Vitamin D and Multiple Sclerosis
57. Season of birth and multiple sclerosis: a systematic review and multivariate meta-analysis
[PMID:31055633 | Multiple authors | Journal of Neurology | 2019] Synthesizes data from more than 145,000 multiple-sclerosis cases and evaluates seasonal birth associations potentially related to prenatal environmental exposures.
58. Does the environment influence multiple sclerosis pathogenesis via UVB light and/or induction of vitamin D?
[PMID:29793727 | Multiple authors | Journal of Neuroimmunology | 2018] Reviews epidemiological and clinical evidence connecting UVB exposure, vitamin D, latitude, immune regulation, and multiple sclerosis.
59. Vitamin D and multiple sclerosis—from epidemiology to prevention
[PMID:26046560 | P. Sundström and J. Salzer | Acta Neurologica Scandinavica | 2015] Reviews evidence linking sun exposure and vitamin D status with multiple-sclerosis susceptibility and considers whether preventive interventions are justified.
60. Ultraviolet radiation, vitamin D and multiple sclerosis
[PMID:26477548 | Multiple authors | Neurodegenerative Disease Management | 2015] Examines both vitamin-D-dependent and independent immunological mechanisms that might connect sunlight exposure with multiple-sclerosis risk and disease activity.
61. The month of birth effect in multiple sclerosis: systematic review, meta-analysis and effect of latitude
[PMID:23152637 | Multiple authors | Journal of Neurology, Neurosurgery & Psychiatry | 2013] Finds seasonal patterns in multiple-sclerosis births and examines whether latitude, maternal vitamin D, and prenatal ultraviolet exposure could contribute.
62. Month of birth as a risk factor for multiple sclerosis: an update
[PMID:23278658 | Multiple authors | Acta Neurologica Scandinavica | 2013] Reviews international studies showing geographic variation in seasonal birth patterns among people who later develop multiple sclerosis.
63. Low maternal exposure to ultraviolet radiation in pregnancy, month of birth, and risk of multiple sclerosis in offspring: longitudinal analysis
[PMID:21030361 | Judith Staples, Anne-Louise Ponsonby and Lynette Lim | BMJ | 2010] Australian population data associate lower ambient ultraviolet exposure during early pregnancy with greater subsequent multiple-sclerosis risk in offspring.
Photodermatoses and Abnormal Responses to Sunlight
64. Efficacy of Therapies for Solar Urticaria: A Systematic Review and Meta-Analysis
[PMID:40869562 | Multiple authors | 2025] Compares antihistamines, phototherapy, omalizumab, and other treatments for the rare UV- and visible-light-triggered disorder solar urticaria.
65. Systematic review of the clinical characteristics and natural history of solar urticaria
[PMID:36796725 | Sheila M. McSweeney et al. | Journal of the American Academy of Dermatology | 2023] Synthesizes clinical evidence on triggering wavelengths, disease duration, symptoms, progression, diagnosis, and outcomes of solar urticaria.
66. Phototesting in erythropoietic protoporphyria trials: A systematic review
[PMID:37052136 | Multiple authors | Experimental Dermatology | 2023] Reviews methods used to measure severe light-induced skin pain and photosensitivity in erythropoietic protoporphyria clinical trials.
67. Pathogenesis of solar urticaria: Classic perspectives and emerging concepts
[PMID:34726314 | Sheila Mary McSweeney et al. | Experimental Dermatology | 2022] Reviews the immune mechanisms responsible for rapid itching, redness, and wheal formation following exposure to particular wavelengths of sunlight.
68. Isolated solar angioedema: A systematic review of the literature
[PMID:33738834 | Multiple authors | Photodermatology, Photoimmunology & Photomedicine | 2021] Reviews rare cases in which sunlight triggers angioedema without typical urticaria and discusses UVA provocation testing and treatment.
69. Recent Developments in the Diagnosis and Management of Photosensitive Disorders
[PMID:29959757 | Multiple authors | Current Dermatology Reports | 2018] Reviews new developments involving idiopathic, drug-induced, genetic, autoimmune, and other photosensitive diseases and their clinical management.
70. Chronic actinic dermatitis
[PMID:24891057 | So Yeon Paek and Henry W. Lim | Dermatologic Clinics | 2014] Reviews an immune-mediated condition in which unusually small doses of ultraviolet or visible radiation can produce persistent eczematous inflammation.
71. Photodermatoses: diagnosis and treatment
[PMID:21442060 | Multiple authors | Deutsches Ärzteblatt International | 2011] Provides a clinical overview of polymorphic light eruption, solar urticaria, chronic actinic dermatitis, phototoxicity, photoallergy, and other abnormal reactions to sunlight.
72. Immunologically mediated photodermatoses: diagnosis and treatment
[PMID:19354331 | Multiple authors | American Journal of Clinical Dermatology | 2009] Reviews polymorphic light eruption, actinic prurigo, hydroa vacciniforme, chronic actinic dermatitis, solar urticaria, diagnostic phototesting, and photoprotection.
73. Diagnosis and treatment of chronic actinic dermatitis
[PMID:12919126 | Robert S. Dawe and James Ferguson | Dermatologic Therapy | 2003] Reviews phototesting, contact allergy, abnormal sensitivity to UVA and UVB, strict sunlight avoidance, topical therapy, and systemic treatment for chronic actinic dermatitis.
Therapeutic Uses of Ultraviolet Radiation
74. Janus kinase inhibitors combined with narrowband ultraviolet B for vitiligo: A systematic review
[PMID:42190750 | Jia Qi Adam Bai et al. | Journal of the American Academy of Dermatology | 2026] Reviews emerging evidence for combining targeted JAK inhibition with narrowband UVB to improve repigmentation in vitiligo.
75. The Effectiveness of Home-Based Phototherapy in Vitiligo: A Systematic Review and Meta-Analysis
[PMID:41804555 | Multiple authors | Photodermatology, Photoimmunology & Photomedicine | 2026] Compares home-based narrowband UVB treatment with office-based therapy, including repigmentation, adherence, adverse effects, and costs.
76. Narrowband UVB Phototherapy in Dermatology: GEF-CILAD 2026 Update
[PMID:42323047 | Multiple authors | 2026] Updates clinical recommendations for narrowband UVB in psoriasis, vitiligo, atopic dermatitis, early mycosis fungoides, and selected photodermatoses.
77. Clinical efficacy and safety profile of handheld narrow band ultraviolet B device therapy in vitiligo – Systematic review and meta-analysis
[PMID:39912150 | Sujay Khandpur, Suvesh Singh and Debopriya Paul | Indian Journal of Dermatology, Venereology and Leprology | 2025] Examines the effectiveness and adverse effects of portable home-use narrowband UVB devices for repigmentation of vitiligo.
78. Narrowband-Ultraviolet B Phototherapy for Psoriasis Treatment in Skin of Color: A Systematic Review and Meta-Analysis
[PMID:40908513 | Multiple authors | Photodermatology, Photoimmunology & Photomedicine | 2025] Evaluates effectiveness of narrowband UVB in darker skin phototypes and highlights the need for representative phototherapy research.
79. Home- vs Office-Based Narrowband UV-B Phototherapy for Patients With Psoriasis: The LITE Randomized Clinical Trial
[PMID:39319513 | Joel M. Gelfand et al. | JAMA Dermatology | 2024] Large pragmatic randomized trial finds home narrowband UVB noninferior to office phototherapy for psoriasis while reducing treatment burden.
80. Phototherapy for atopic dermatitis: Systematic review and network meta-analysis of randomized controlled trials
[PMID:34653289 | Hui Xiao et al. | Photodermatology, Photoimmunology & Photomedicine | 2022] Compares several forms of ultraviolet phototherapy for atopic dermatitis and assesses their relative effectiveness and potential long-term risks.
81. Phototherapy for Cutaneous T-Cell Lymphoma
[PMID:31753185 | Arthur Marka and Joi B. Carter | Dermatologic Clinics | 2020] Reviews narrowband UVB and PUVA for mycosis fungoides, including treatment protocols, maintenance, disease stage, and photocarcinogenic risk.
82. Advances in phototherapy for psoriasis and atopic dermatitis
[PMID:31575297 | Lajos Kemény, Emese Varga and Zoltan Novak | Expert Review of Clinical Immunology | 2019] Reviews ultraviolet and newer light-based treatments for psoriasis and atopic dermatitis, including efficacy, dosing, mechanisms, and safety.
83. Comparison of Narrowband UV-B With Psoralen-UV-A Phototherapy for Patients With Early-Stage Mycosis Fungoides: A Systematic Review and Meta-analysis
[PMID:30698622 | Kevin Phan et al. | JAMA Dermatology | 2019] Compares narrowband UVB and PUVA for early-stage cutaneous T-cell lymphoma and evaluates response, recurrence, and adverse effects.
84. Phototherapy for Vitiligo: A Systematic Review and Meta-analysis
[PMID:28355423 | Multiple authors | JAMA Dermatology | 2017] Synthesizes prospective evidence on narrowband UVB and PUVA and estimates the degree of repigmentation achievable after different treatment durations.
85. Ultraviolet B Phototherapy for Psoriasis: Review of Practical Guidelines
[PMID:26872953 | Multiple authors | American Journal of Clinical Dermatology | 2016] Reviews dosing, frequency, safety, adjunctive therapies, and practical clinical use of narrowband UVB and targeted UVB for psoriasis.
86. Ultraviolet phototherapy for cutaneous diseases: a concise review
[PMID:26464123 | Multiple authors | Oral Diseases | 2015] Reviews therapeutic UVA, UVB, narrowband UVB, and PUVA for psoriasis, eczema, vitiligo, morphea, and other dermatologic diseases.
87. Treatment of vitiligo with NB-UVB: A systematic review
[PMID:25102894 | Multiple authors | Journal of the European Academy of Dermatology and Venereology | 2014] Reviews randomized trials comparing narrowband UVB with UVA, PUVA, and excimer-light treatments for vitiligo.
Occupational, Environmental and Climate-Related UV Exposure
88. Effects of Ozone-Depleting Substances on Ultraviolet Radiation and Skin Cancer Rates in Australia and the United States of America
[PMID:42130768 | Julia Lee-Taylor et al. | GeoHealth | 2026] Models how ozone-depleting substances alter surface ultraviolet radiation and estimates resulting effects on keratinocyte cancer, melanoma, and cataracts.
89. Relationship between climate change and skin cancer and implications for prevention and management: a scoping review
[PMID:38262229 | Multiple authors | Public Health | 2024] Reviews possible pathways linking climate change with ultraviolet exposure, outdoor behavior, heat, air pollution, occupational risks, skin cancer, and prevention.
90. Occupational Exposure to Artificial Ultraviolet Radiation from Welding in Australia
[PMID:39539586 | Lin Fritschi et al. | International Journal of Environmental Research and Public Health | 2024] Surveys welders and supervisors to evaluate ocular and skin exposure to artificial UV radiation and the use of workplace protective measures.
91. UV radiation exposure in welders: impact on the skin and eyes
[PMID:31675405 | D. Michael Piernick II, Marla N. Jahnke and Alice C. Watson | Cutis | 2019] Uses clinical cases to illustrate actinic damage, photosensitive disease, squamous cell carcinoma, and ocular risks associated with welding arcs.
92. Review on Nonoccupational Personal Solar UV Exposure Measurements
[PMID:29856894 | Alois W. Schmalwieser and Anna Maria Siani | Photochemistry and Photobiology | 2018] Reviews decades of personal UV dosimetry during recreation and everyday activities and explains how behavior and body orientation modify individual ultraviolet dose.
93. Occupational exposure of welders to ultraviolet and blue-light radiation emitted during TIG and MMA welding based on field measurements
[PMID:23650770 | Multiple authors | Medycyna Pracy | 2013] Field measurements show that welding can exceed recommended UV exposure limits within very short periods without appropriate eye, face, neck, and skin protection.
94. Is occupational solar ultraviolet irradiation a relevant risk factor for basal cell carcinoma? A systematic review and meta-analysis of the epidemiological literature
[PMID:21605109 | A. Bauer, T. L. Diepgen and J. Schmitt | British Journal of Dermatology | 2011] Meta-analysis finds increased basal cell carcinoma risk among outdoor workers and discusses latitude and nonoccupational exposure as important modifiers.
95. Impact of climate change on skin cancer
[PMID:19531614 | Multiple authors | Journal of the Royal Society of Medicine | 2009] Discusses how ozone, temperature, cloud patterns, outdoor behavior, and environmental change could influence future UV exposure and skin-cancer incidence.
96. Meta-analysis of risk factors for cutaneous melanoma: II. Sun exposure
[PMID:15617990 | Multiple authors | European Journal of Cancer | 2005] Synthesizes 57 studies and finds that intermittent exposure and sunburn are stronger melanoma predictors than simple measures of chronic occupational exposure.
97. Randomized trial testing a worksite sun protection program in an outdoor recreation industry
[PMID:16009748 | David B. Buller et al. | Health Education & Behavior | 2005] Evaluates the Go Sun Smart program at ski areas and reports improved sun-safety awareness and fewer employee sunburns where the intervention was implemented.
98. A workplace intervention for increasing outdoor workers' use of solar protection
[PMID:8279616 | Multiple authors | American Journal of Public Health | 1993] Randomized intervention demonstrates that workplace education and skin screening can increase protective behavior among outdoor workers.
Sun Protection, UV Index and Behavioral Interventions
99. Sun Safety Policies in Canadian Elementary Schools: A Comprehensive Scoping Review and Jurisdictional Scan of Canadian Provincial Government Policies
[PMID:41243290 | Multiple authors | 2026] Identifies gaps between public-health sun-safety recommendations and actual educational policies governing shade, hats, sunscreen, outdoor scheduling, and UV protection.
100. The effectiveness of educational programmes in promoting sun protection among children under the age of 18: a systematic review and meta-analysis
[PMID:34379846 | Multiple authors | Journal of Cancer Education | 2021]
Reviews controlled interventions aimed at improving children's sunscreen use, clothing, shade seeking, UV knowledge, and other protective behaviors.
101. Effect of a Face-Aging Mobile App-Based Intervention on Skin Cancer Protection Behavior in Secondary Schools in Brazil: A Cluster-Randomized Clinical Trial
[PMID:32374352 | Multiple authors | JAMA Dermatology | 2020]
Tests digitally aged photographs showing future UV damage as a behavioral intervention to encourage adolescents to improve sun protection.
102. Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis
[PMID:29620003 | Multiple authors | European Journal of Dermatology | 2018]
Reviews observational studies and trials and illustrates the difficulty of estimating sunscreen effectiveness when behavior, exposure, formulation, and confounding vary substantially.
103. A Mobile Technology Intervention With Ultraviolet Radiation Dosimeters and Smartphone Apps for Skin Cancer Prevention in Young Adults: Randomized Controlled Trial
[PMID:30487115 | Multiple authors | JMIR mHealth and uHealth | 2018]
Tests wearable UV dosimeters and a smartphone application and finds that personalized exposure feedback can reduce some periods of unprotected UV exposure.
104. A Randomized Controlled Trial of a Mobile Medical App for Kidney Transplant Recipients: Effect on Use of Sun Protection
[PMID:26900599 | Multiple authors | Transplantation Direct | 2016]
Evaluates digital sun-safety education for transplant recipients, a group with greatly increased susceptibility to UV-associated keratinocyte cancers.
105. Evaluation of immediate and 12-week effects of a smartphone sun-safety mobile application: a randomized clinical trial
[PMID:25629819 | Multiple authors | JAMA Dermatology | 2015]
Tests an application delivering UV Index information and sun-protection reminders and finds improvement in selected protective behaviors.
106. Smartphone mobile application delivering personalized, real-time sun protection advice: a randomized clinical trial
[PMID:25629710 | Multiple authors | JAMA Dermatology | 2015]
Finds that personalized mobile advice can increase shade seeking and reduce some unprotected exposure, although effects differ across individual behaviors.
107. Sunscreen use and melanocytic nevi in children: a systematic review
[PMID:22994908 | Multiple authors | Pediatric Dermatology | 2013]
Reviews studies of sunscreen and childhood mole development and highlights confounding from sun exposure, skin phenotype, sunscreen application, and behavioral compensation.
108. Is the Global Solar UV Index an effective instrument for promoting sun protection? A systematic review
[PMID:21730253 | Multiple authors | Health Education Research | 2011]
Finds that awareness of the UV Index does not necessarily translate into understanding or protective behavior and identifies weaknesses in public-health communication.
UV-Related Effects on the Lips and Eyes
109. Treatment of actinic cheilitis: a systematic review
[PMID:31011833 | Multiple authors | Clinical Oral Investigations | 2019]
Reviews treatments for actinic cheilitis, a potentially malignant lower-lip disorder strongly associated with long-term solar ultraviolet exposure.
110. Occupational Exposure to Solar Radiation at Different Latitudes and Pterygium: A Systematic Review of the Last 10 Years of Scientific Literature
[PMID:29278403 | Alberto Modenese and Fabriziomaria Gobba | International Journal of Environmental Research and Public Health | 2018]
Reviews evidence that prolonged occupational sunlight exposure increases pterygium risk and supports UV-protective eyewear and other preventive measures for outdoor workers.
