Assessment of UV exposure in a young metropolitan population

University dissertation from Stockholm : Karolinska Institutet, Department of Public Health Sciences

Abstract: Overexposure to UVR causes >80% of skin cancers, and >30% of all diagnosed cancers in western societies, Sweden included, are skin cancers. Overexposure in terms of UV-induced erythema during childhood and adolescence is considered particularly harmful. The widespread use of sunbeds among adolescents and young adults contribute considerably to UV exposure. The objectives of this thesis were to i) analyze the relation of sunbed use to phenotype, erythema, sunscreen use and skin disease in adolescents, and ii) to analyze adolescent's sunbed use and its relation to sex, age, attitudes, and smoking, iii) to estimate the proportion of artificial/natural UV exposure in terms of population doses, considering exposed skin area, iv) to assess UV exposure and erythema in the population aged 13-50 years, and v) to compare two cross sectional studies (1993 and 1999) of adolescents' sunbed use, including the relation of sunbed use to age, phenotype, sunscreen use and smoking. Two cross-sectional surveys were applied, with participants (ages 15-19 years) being selected by stratified random sampling of classrooms (1993), and stratified random sampling by age (13-19 years and 20-50 years respectively) from the national census registry. During 12 months preceding the survey in 1993, 70% of female, and 44% of male adolescents had used sunbeds, 44% of them had reported sunbed erythema. Sunbeds were used in equal proportions, regardless of skin reaction upon sunbed use. Sunbed use was positively related to phenotype, sunscreen use intentional outdoor tanning, and smoking. Population doses of natural UVR in Sweden, and estimates of exposure to artificial UVR suggested that erythemally effective UV-doses from sunbeds may be equivalent to those from the sun, considering exposed skin area. During 12 months preceding the survey in 1999, almost half of responders aged 13-50 years had been on vacation to a sunny seaside resort abroad, 33% of females, and 17% of males tanned outdoors, almost every second female and one of four males used sunbeds. One adult of four had given up sunbeds. Females used sunbeds and tanned outdoors twice as often as males, particularly adolescents aged 17-19 years and adults aged 20-29 years. Sunburn was reported by 55% after tanning outdoors in Sweden, abroad, or both, and one third of those reported sunbed erythema. Outdoor tanning, sunbed use and related erythema was particularly frequent in young females. Levels of sunbed use and sunbed erythema among adolescents aged 15-19 years was 50% lower in 1999 than in 1993, but outdoor tanning had increased. In both 1993 and 1999, the same dominance of females was observed in sunbed use, and its association with phenotype, outdoor tanning sunscreen use, and smoking. The studies confirm previous findings that young populations from high-latitude areas actively seek high risk settings of overexposure to UVR. Risk behaviors are positively related, particularly in females, erythema is experienced by a high proportion of the population at an early age, and the accumulated incidence and prevalence of UV-induced erythema is high. From a skin cancer control perspective, initiatives should be taken to promote sun awareness as a conceptual norm from early age, including the implementation of alternative tourism, in combination with restrictive international policies regarding sunbed use, and observation of these policies.

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