Determinants of skin sensitivity to solar irradiation

Abstract

Background: Acute effects of UV irradiation include UV-induced erythema. Sunlight plays an important role in the development of skin cancer. Several predictive factors of UV-induced erythema could also be predictive for skin cancer. Objective: Our objective was to quantitatively assess phenotypical and nutritional determinants of sensitivity to UV irradiation, as assessed by the minimal erythema dose (MED). Design: We conducted a cross-sectional study among 335 volunteers. Sensitivity to UV irradiation was established through assessment of the MED. Phenotypical determinants, including skin melanin content, hair color and iris color were determined by skin reflectance spectrometry, a subjective questionnaire and an objective classification system, respectively. Furthermore, dietary exposure was measured by carotenoids, vitamin C, retinol and a-tocopherol in serum. Results: Male subjects were found to be more sensitive to UV irradiation; that is, the MED was significantly lower compared to female subjects. Skin melanin content, which was positively associated with iris color in both sexes and with hair color in men, was the main phenotypical determinant of sensitivity to UV irradiation. No associations were found between serum carotenoids and MED in the total study group. Vitamin C was inversely associated with MED. However, associations between carotenoids concentrations and MED showed a positive trend in subjects with melanin values above and a negative trend in subjects below the median after adjustment for gender and total cholesterol. Conclusions: Skin melanin content and gender are important determinants of sensitivity to UV irradiation. No relation was found between serum carotenoids and MED in the total study group. The inverse association between vitamin C and MED was against our hypothesis. For the modifying effect of melanin on the association between carotenoids and MED, we do not have a clear biological explanation.

Comportamento relativo à exposição e proteção solar na população de 15 anos ou mais de 15 capitais brasileiras e Distrito Federal, 2002-2003

“…Apesar de existirem estudos científicos apontando para outras formas de proteção baseadas em aspectos endógenos, ou seja, os aspectos protetores conferidos pelos hábitos alimentares, em que micronutrientes podem funcionar como absorvedores de exposição ou antioxidantes 53,54 , a proteção pelo uso de roupas adequadas, uso de protetor solar, utilização de chapéus e evitar o Sol ainda são as principais recomendações com relação à prevenção primária do câncer de pele em geral 37 . Os efeitos a curto prazo das medidas de proteção têm sido avaliados pela redução de freqüências de lesões precursoras para as doenças mais graves que podemos relacionar com a exposição solar 8,55,56 .…”

Cytogenetic alterations in nonmelanoma skin cancer: A review

“…The beneficial effects of UVR exposure of the skin are limited to the synthesis of vitamin D and skin pigment stimulation, the latter reducing skin sensitivity to UVR (Bykov et al, 2000;Broekmans et al, 2003). In contrast, growing evidence in the form of photodamage to the skin including sunburn, photoaging, and skin cancer demonstrates the deleterious effects of UVR exposure (Kraemer, 1997;Sarasin, 1999).…”

Grading of Iris Color with an Extended Photographic Reference Set

“…39 Seddon et al 40 developed a system with 4 reference photographs (5 categories), that was also used in later studies. [41][42][43] Most of these grading systems use 2 to 5 categories for eye color, which is too coarse (discretisation error too high) to discern the subtle differences on the blue side which are expected to induce relatively strong variations in retinal straylight, as explained above. In the last decade some objective classification systems have been proposed, based on automated image analysis by a computer using a calibrated software package (Bee WH, et al IOVS 1997;38:ARVO Abstract 3797).…”