Repeated ultraviolet exposure affords the same protection against DNA photodamage and erythema in human skin types II and IV but is associated with faster DNA repair in skin type IV
Open accessAbstract
We have investigated the photoprotective properties of induced pigmentation using erythema and epidermal DNA photodamage as endpoints. Previously unexposed buttock skin of 12 young, healthy adults (six skin type II and six skin type IV) was exposed daily (Monday to Friday) for 2 wk (days 1-12) with 0.65 minimal erythema dose of solar simulated radiation. Mean skin type IV minimal erythema dose was 1.8-fold greater than for skin type II. Compared to skin type II, solar simulated radiation treatments produced less erythema and more tanning in skin type IV. To assess DNA photodamage, biopsies were taken and prepared for paraffin sections that were stained with a monoclonal antibody for thymine dimers. Thymine dimers were quantified by image analysis. The single exposure data (0.65 and 2 minimal erythema dose) showed that DNA damage was related to physical dose (J per cm2) independent of skin type. Our data also showed that DNA photodamage accumulates in both skin types with repeated, suberythemal doses of solar simulated radiation. On day 12, there were more thymine dimers in skin type IV than skin type II, again indicating that physical rather than biologic dose determines the level of DNA damage. Comparisons on days 12 and 19, however, showed a much greater loss of thymine dimers in skin type IV, suggesting better thymine dimer repair. Protection factors for erythema and thymine dimers were calculated and shown to be about 2 in both skin types. This provides further indirect evidence that DNA is a chromophore for erythema, but also suggests that a tan may not be the major factor in natural photoprotection.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Eumelanin in darker skin types plays a key role in reducing UV-induced DNA damage in keratinocytes.
“Consequently, eumelanin in darker skin types plays a key role in reducing UV-induced DNA damage in keratinocytes [24,26].”
From A Comprehensive Review of the Role of UV Radiation in Photoaging Processes Between Different Types of Skin (2025) · cites this paper as [24]
The study reports modest protection against UV-induced epidermal DNA damage after repeated exposure, but finds similar protection in skin types II and IV. Its Discussion (pp. 825–829) says that protection does not seem to be related to tanning per se and suggests faster DNA repair in type IV. It does not establish that eumelanin plays a key role in reducing keratinocyte DNA damage. (LLM, conf=0.84)
Experimental — accuracy not yet measuredDNA damage repair mechanisms are more effective in skin of color than in lighter skin types.
“Furthermore, studies have shown that DNA damage repair mechanisms are more effective in skin of color than in lighter skin types [24].”
From A Comprehensive Review of the Role of UV Radiation in Photoaging Processes Between Different Types of Skin (2025) · cites this paper as [24]
The Results and Discussion (pp. 825–829) report faster loss of UV-induced DNA lesions in skin type IV than type II during the week after repeated exposure, which the authors interpret as suggesting greater repair in type IV. The claim generalizes that finding to skin of color versus lighter skin types overall, without the study’s exposure condition or its qualification that greater repair is inferred. (LLM, conf=0.85)
Experimental — accuracy not yet measuredCumulative photodamage in dark skin is evidenced by fine lines, sagging skin, and irregular pigmentation.
“This is evidenced by fine lines, sagging skin, and irregular pigmentation.”
From A Comprehensive Review of the Role of UV Radiation in Photoaging Processes Between Different Types of Skin (2025) · cites this paper as [24]
The opening summary (p. 825) reports that DNA photodamage accumulated in skin type IV after repeated UV exposure. It does not identify fine lines, sagging skin, or irregular pigmentation as signs of that damage; the study measured thymine dimers, erythema, and tanning instead. (LLM, conf=0.85)
Experimental — accuracy not yet measuredTanning affords only moderate protection against cellular damage from UVR and appears to be triggered by signals from UVR-damaged DNA.
“Tanning affords only moderate protection against cellular damage from UVR (74,75) and, in fact, appears to be triggered by signals from UVR-damaged DNA.”
From Human skin pigmentation as an adaptation to UV radiation (2010) · cites this paper as [75]
Although dark skin gains certain advantages from the protective effects of melanin, it is not invulnerable to the costs of UV radiation; persistent sun exposure can cause cumulative photodamage.
“Although dark skin gains certain advantages from the protective effects of melanin, it is not invulnerable to the costs of UV radiation. Persistent sun exposure can nevertheless cause cumulative photodamage [24,29].”
From A Comprehensive Review of the Role of UV Radiation in Photoaging Processes Between Different Types of Skin (2025) · cites this paper as [24]
DNA strand breaks caused by UVA were observed more frequently in individuals with lighter skin.
“Additionally, DNA strand breaks caused by UVA were observed more frequently in individuals with lighter skin [19,24].”
From A Comprehensive Review of the Role of UV Radiation in Photoaging Processes Between Different Types of Skin (2025) · cites this paper as [24]
The Materials and Methods describe solar-simulated radiation exposure, and Figure 3 reports thymine-dimer damage by skin type; neither addresses UVA-induced DNA strand breaks. The claim’s specific lesion and exposure cannot be verified from this paper (page numbers unavailable in our copy). (LLM, conf=0.76)
Experimental — accuracy not yet measured
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
The validity and practicality of sun-reactive skin types I through VI
Fitzpatrick, T. B. (1988) · Archives of Dermatology · doi:10.1001/archderm.1988.01670060015008 · Cited by 4,339 · see citing works
Mutation hotspots due to sunlight in the p53 gene of nonmelanoma skin cancers.
Ziegler, A., Leffell, D. J., Kunala, S., Sharma, H. W., Gailani, M. R., Simon, J. A., Halperin, A. J., Baden, H. P., Shapiro, P. E., & Bale, A. E. (1993) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.90.9.4216 · Cited by 739 · see citing works
Kollias, N., Sayre, R. M., Zeise, L., & Chedekel, M. R. (1991) · Journal of Photochemistry and Photobiology B: Biology · doi:10.1016/1011-1344(91)80147-a · Cited by 482 · see citing works
Photoprotection by melanin—a comparison of black and Caucasian skin
Kaidbey, K. H., Agin, P. P., Sayre, R. M., & Kligman, A. M. (1979) · Journal of the American Academy of Dermatology · doi:10.1016/s0190-9622(79)70018-1 · Cited by 467 · see citing works
Mori, T., Nakane, M., Hattori, T., Matsunaga, T., Ihara, M., & Nikaido, O. (1991) · Photochemistry and Photobiology · doi:10.1111/j.1751-1097.1991.tb02010.x · Cited by 410 · see citing works
Young, A. R., Harrison, G. I., Chadwick, C. A., Nikaido, O., Ramsden, J., & Potten, C. S. (1998) · Journal of Investigative Dermatology · doi:10.1046/j.1523-1747.1998.00436.x · Cited by 235 · see citing works
Self-citationXeroderma pigmentosum and the role of UV-induced DNA damage in skin cancer
STEEG, H. V., & Kraemer, K. H. (1999) · Molecular Medicine Today · doi:10.1016/s1357-4310(98)01394-x · Cited by 211 · see citing works
Ultraviolet Radiation Induced Signature Mutations in Photocarcinogenesis
Wikonkál, N. M., & Brash, D. E. (1999) · Journal of Investigative Dermatology Symposium Proceedings · doi:10.1038/sj.jidsp.5640173 · Cited by 207 · see citing works
Eller, M. S., Maeda, T., Magnoni, C., Atwal, D., & Gilchrest, B. A. (1997) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.94.23.12627 · Cited by 204 · see citing works
DNA photodamage stimulates melanogenesis and other photoprotective responses
Gilchrest, B. A., & Eller, M. S. (1999) · Journal of Investigative Dermatology Symposium Proceedings · doi:10.1038/sj.jidsp.5640178 · Cited by 182 · see citing works
Lookingbill, D. P., Lookingbill, G., & LEPPARD, B. J. (1995) · Journal of the American Academy of Dermatology · doi:10.1016/0190-9622(95)90352-6 · Cited by 173 · see citing works
Young, A. R., Chadwick, C. A., Harrison, G. I., Hawk, J. L. M., Nikaido, O., & Potten, C. S. (1996) · Journal of Investigative Dermatology · doi:10.1111/1523-1747.ep12349031 · Cited by 147 · see citing works
Self-citationGreen, S., & Kelly, R. B. (1992) · The Journal of Cell Biology · doi:10.1083/jcb.117.1.47 · Cited by 145 · see citing works
Kraemer, K. H., Levy, D. D., Parris, C. N., Gozukara, E. M., Moriwaki, S., Adelberg, S., & Seidman, M. M. (1994) · Journal of Investigative Dermatology · doi:10.1038/jid.1994.17 · Cited by 118 · see citing works
Epidermal thickness, skin pigmentation and constitutive photosensitivity
Lock‐Andersen, J., Therkildsen, P., Olivarius, F. D. F., Gniadecka, M., Dahlstrem, K., Poulsen, T., & Wulf, H. C. (1997) · Photodermatology Photoimmunology & Photomedicine · doi:10.1111/j.1600-0781.1997.tb00220.x · Cited by 116 · see citing works
Berg, R. J. W., Ruven, H. J. T., Sands, A., de Gruijl, F. R., & Mullenders, L. H. F. (1998) · Journal of Investigative Dermatology · doi:10.1111/j.1523-1747.1998.00173.x · Cited by 91 · see citing works
Mawn, V. B., & Fleischer, A. B. (1993) · Journal of the American Academy of Dermatology · doi:10.1016/0190-9622(93)70274-w · Cited by 86 · see citing works
Tanning in Human Skin Types II and III Offers Modest Photoprotection Against Erythema
Sheehan, J. M., Potten, C. S., & Young, A. R. (1998) · Photochemistry and Photobiology · doi:10.1111/j.1751-1097.1998.tb02518.x · Cited by 83 · see citing works
Self-citationGniadecka, M., Wulf, H. C., Mortensen, N. N., & Poulsen, T. (1996) · Acta Dermato Venereologica · doi:10.2340/0001555576429432 · Cited by 83 · see citing works
Sunburn Protection by Longwave Ultraviolet Radiation-Induced Pigmentation
Kaidbey, K. H. (1978) · Archives of Dermatology · doi:10.1001/archderm.1978.01640130010002 · Cited by 81 · see citing works
Young, A. R., Sheehan, J. M., Chadwick, C. A., & Potten, C. S. (2000) · Journal of Investigative Dermatology · doi:10.1046/j.1523-1747.2000.00012.x · Cited by 79 · see citing works
Self-citationYoung, A. R., Potten, C. S., Chadwick, C. A., MURPHY, G. M., Hawk, J. L. M., & Cohen, A. J. (1991) · Journal of Investigative Dermatology · doi:10.1111/1523-1747.ep12491807 · Cited by 71 · see citing works
Self-citationEffect of age on the formation and repair of UV photoproducts in human skin in situ
Xu, G., Snellman, E., Bykov, V. J. N., Jansén, C. T., & Hemminki, K. (2000) · Mutation Research/DNA Repair · doi:10.1016/s0921-8777(99)00069-5 · Cited by 65 · see citing works
Changing patterns in incidence of non-melanoma skin cancer.
Green, A. (1992) · PubMed · Cited by 63 · see citing works
Sunbeds in current use in Scotland: a survey of their output and patterns of use
Mcginley, Martin, & Mackie (1998) · British Journal of Dermatology · doi:10.1046/j.1365-2133.1998.02406.x · Cited by 55 · see citing works
Potten, C. S., Chadwick, C. A., Cohen, A. J., Nikaido, O., Matsunaga, T., Schipper, N. W., & Young, A. R. (1993) · International Journal of Radiation Biology · doi:10.1080/09553009314550421 · Cited by 53 · see citing works
Self-citationBataille, V. A., Bykov, V. J. N., Sasieni, P. D., Harulow, S., Cuzick, J. M., & Hemminki, K. (2000) · British Journal of Dermatology · doi:10.1111/j.1365-2133.2000.03698.x · Cited by 39 · see citing works
Olivarius, F. D. F., Wulf, H. C., Therkildsen, P., Poulsen, T., Crosby, J. C., & Norval, M. (1997) · Archives of Dermatological Research · doi:10.1007/s004030050230 · Cited by 37 · see citing works
LASER DOPPLER VELOCIMETRY TO QUANTIFY UV‐B INDUCED INCREASE IN HUMAN SKIN BLOOD FLOW
Young, A. R., Guy, R. H., & Maibach, H. I. (1985) · Photochemistry and Photobiology · doi:10.1111/j.1751-1097.1985.tb01585.x · Cited by 33 · see citing works
Self-citationInhibition of UV Radiation‐Induced DNA Damage by a 5‐Methoxypsoralen Tan in Human Skin
Young, A. R., Potten, C. S., Chadwick, C. A., MURPHY, G. M., & COHEN, A. J. (1988) · Pigment Cell Research · doi:10.1111/j.1600-0749.1988.tb00131.x · Cited by 32 · see citing works
Self-citationUltraviolet Light Sensitivity and Prolonged UVR-Erythema
Wilson, P. D., Kaidbey, K. H., & Kligman, A. M. (1981) · Journal of Investigative Dermatology · doi:10.1111/1523-1747.ep12495667 · Cited by 25 · see citing works
Skin Disease in the Cuna Indians
McFADDEN, A. W. (1961) · Archives of Dermatology · doi:10.1001/archderm.1961.01580180129020 · Cited by 21 · see citing works
Light-induced skin cancer and prolonged UV-erythema
Jung, E. G., Furtw�ngler, M., Klostermann, G. F., & Bohnert, E. (1980) · Archives of Dermatological Research · doi:10.1007/bf00416919 · Cited by 21 · see citing works
Kipp, C., Lewis, E. J., & Young, A. R. (1998) · Photochemistry and Photobiology · doi:10.1111/j.1751-1097.1998.tb05175.x · Cited by 15 · see citing works
Self-citationReaction to UV-induced erythema in young patients with basal cell carcinoma.
Aubin, F., Zultak, M., Blanc, D., Terrasse, F., Quencez, E., & Agache, P. G. (1989) · PubMed · Cited by 15 · see citing works
Clearance of UVB‐induced erythema in patients with non‐melanoma skin cancer
Holmes, S. C., Aitchison, T. C., & MacKie, R. M. (1997) · Photodermatology Photoimmunology & Photomedicine · doi:10.1111/j.1600-0781.1997.tb00228.x · Cited by 4 · see citing works
Flagged first, then by citations
Research works printed but not linked: 1
- Kollias N, Sayre RM, Zeise L, Chedekel MR: Photoprotection by melanin. [Review]. J Photochem Photobiol B ± Biol 9:135±160, 1991
Cited by
Sorted by citations
The Protective Role of Melanin Against UV Damage in Human Skin <sup>†</sup>
Brenner, M., & Hearing, V. J. (2008) · Photochemistry and Photobiology · doi:10.1111/j.1751-1097.2007.00226.x · Cited by 1,741 · see citing works
Human skin pigmentation as an adaptation to UV radiation
Jablonski, N. G., & Chaplin, G. (2010) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.0914628107 · Cited by 728 · see citing works
Formation of UV-induced DNA damage contributing to skin cancer development
Cadet, J., & Douki, T. (2018) · Photochemical & Photobiological Sciences · doi:10.1039/c7pp00395a · Cited by 435 · see citing works
Sklar, L. R., Almutawa, F., Lim, H. W., & Hamzavi, I. (2012) · Photochemical & Photobiological Sciences · doi:10.1039/c2pp25152c · Cited by 354 · see citing works
Del Bino, S., Duval, C., & Bernerd, F. (2018) · International Journal of Molecular Sciences · doi:10.3390/ijms19092668 · Cited by 315 · see citing works
Acute effects of UVR on human eyes and skin
Young, A. R. (2006) · Progress in Biophysics and Molecular Biology · doi:10.1016/j.pbiomolbio.2006.02.005 · Cited by 267 · see citing works
Self-citationMelanogenesis: a photoprotective response to DNA damage?
Agar, N., & Young, A. R. (2005) · Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis · doi:10.1016/j.mrfmmm.2004.11.016 · Cited by 254 · see citing works
Self-citationRegulation of human skin pigmentation and responses to ultraviolet radiation
Miyamura, Y., Coelho, S. G., Wolber, R., Miller, S. A., Wakamatsu, K., Zmudzka, B. Z., Ito, S., Smuda, C., Passeron, T., Choi, W., et al. (2007) · Pigment Cell Research · doi:10.1111/j.1600-0749.2006.00358.x · Cited by 250 · see citing works
Yamaguchi, Y., Takahashi, K., Zmudzka, B. Z., Kornhauser, A., Miller, S. A., Tadokoro, T., Berens, W., Beer, J. Z., Hearing, V. J., Yamaguchi, Y., et al. (2006) · The FASEB Journal · doi:10.1096/fj.06-5725fje · Cited by 205 · see citing works
Seité, S., Fourtanier, A., Moyal, D., & Young, A. R. (2010) · British Journal of Dermatology · doi:10.1111/j.1365-2133.2010.10018.x · Cited by 142 · see citing works
Self-citationThe impact of skin colour on human photobiological responses
Fajuyigbe, D., & Young, A. R. (2016) · Pigment Cell & Melanoma Research · doi:10.1111/pcmr.12511 · Cited by 108 · see citing works
Self-citationPhotoprotection in specific populations: Children and people of color
Cestari, T., & Buster, K. (2017) · Journal of the American Academy of Dermatology · doi:10.1016/j.jaad.2016.09.039 · Cited by 77 · see citing works
Shih, B. B., Farrar, M. D., Cooke, M. S., Osman, J., Langton, A. K., Kift, R., Webb, A. R., Berry, J. L., Watson, R. E. B., Vail, A., et al. (2018) · Journal of Investigative Dermatology · doi:10.1016/j.jid.2018.04.015 · Cited by 64 · see citing works
The benefit of daily photoprotection
Seité, S., & Fourtanier, A. M. A. (2008) · Journal of the American Academy of Dermatology · doi:10.1016/j.jaad.2007.04.036 · Cited by 62 · see citing works
New insights into pigmentary pathways and skin cancer: Insights into pigmentation and cancer
Miller, A. J., & Tsao, H. (2010) · British Journal of Dermatology · doi:10.1111/j.1365-2133.2009.09565.x · Cited by 46 · see citing works
Fajuyigbe, D., Douki, T., van Dijk, A., Sarkany, R. P. E., & Young, A. R. (2021) · Pigment Cell & Melanoma Research · doi:10.1111/pcmr.12956 · Cited by 39 · see citing works
Self-citationSkin and hair pigmentation variation in Island Melanesia
Norton, H. L., Friedlaender, J. S., Merriwether, D. A., Koki, G., Mgone, C. S., & Shriver, M. D. (2006) · American Journal of Physical Anthropology · doi:10.1002/ajpa.20343 · Cited by 36 · see citing works
Mechanisms of and variables affecting UVR photoadaptation in human skin
Garmyn, M., Young, A. R., & Miller, S. A. (2018) · Photochemical & Photobiological Sciences · doi:10.1039/c7pp00430c · Cited by 33 · see citing works
Self-citationPhotoprotection in skin of color
Seck, S., Hamad, J., Schalka, S., & Lim, H. W. (2022) · Photochemical & Photobiological Sciences · doi:10.1007/s43630-022-00314-z · Cited by 20 · see citing works
Brar, G., Dhaliwal, A., Brar, A. S., Sreedevi, M., Ahmadi, Y., Irfan, M., Golbari, R., Zumárraga, D., Yateem, D., Lysak, Y., et al. (2025) · Cureus · doi:10.7759/cureus.81109 · Cited by 22 · see citing works
“Additionally, DNA strand breaks caused by UVA were observed more frequently in individuals with lighter skin [19,24].”
InfluentialDennis, L. K., & Lowe, J. B. (2013) · Photodermatology, Photoimmunology & Photomedicine · doi:10.1111/phpp.12040 · Cited by 10 · see citing works
Interaction of solar radiation with the human skin
Rajan, R. (2024) · Sunscreens for Skin of Color · doi:10.1007/978-981-97-3195-4_2 · Cited by 2 · see citing works
- Authors
- Cragg, N., Chadwick, C. A., Potten, C. S., Sheehan, J. M., & Young, A. R.
- Affiliations
- Cancer Research UK Manchester Institute (GB)
- St Thomas' Hospital (GB)
- Corresponding author
- Sheehan, John M.
- Venue
- Journal of Investigative Dermatology
- Publisher
- Elsevier BV
- Published
- 2002-05
- Volume
- 118
- Issue
- 5
- Pages
- 825-829
- ISSN
- 0022-202X (ISSN-L)
- OpenAlex
- W2044750930
- Cited by
- 140
- References
- 36
- Citations by year
- 2026: 3 · 2025: 3 · 2024: 3 · 2023: 3 · 2022: 5 · 2021: 1 · 2020: 6 · 2019: 2 · 2018: 9 · 2017: 6 · 2016: 11 · 2014: 8 · 2013: 4 · 2012: 6
- FWCI
- 8.03
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Licence
- Locations
- Journal of Investigative Dermatology (publishedVersion)
- PubMed (publishedVersion)
- Research Portal (King's College London) (submittedVersion)
- Funders
- European Commission (ENV4-CT97, ENV4-CT97-0556)
- Topics
- Health Sciences › Medicine › Dermatology › Skin Protection and Aging
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › melanin and skin pigmentation
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › DNA Repair Mechanisms
- Keywords
- photoprotection, DNA photodamage, thymine dimers, DNA repair, erythema, skin type, tanning, simulated solar radiation, protection factor, UV-induced pigmentation
- MeSH terms
- DNA Damage, DNA Repair, Epidermis, Erythema, Humans, Melanins, Pyrimidine Dimers, Skin Pigmentation, Ultraviolet Rays
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
