Fair, and still a sun lover: risk of gallstone formation.

STUDY OBJECTIVE The aim was to evaluate the hypothesis that sunlight exposure leads to the development of gallstones in people with a sun sensitive skin. DESIGN AND SETTING This was a case-control study among 206 white patients referred for an ultrasound examination of the gallbladder. Sunlight exposure and skin sensitivity were retrospectively assessed by a structured questionnaire. The questionnaire was taken before the outcome of the ultrasound examination was known, so that the patients and the interviewers were blind to the outcome. The main outcome measure was gallstones in the gallbladder detected by ultrasound. MAIN RESULTS 87 patients had gallstones (cases), 119 had none (controls). In subjects with a skin sensitive for sun (Fitzpatrick skin type I) a positive attitude to sunbathing was associated with a higher risk of gallstones than a negative attitude. In subjects with an insensitive skin (skin type IV) no association was found. CONCLUSIONS This study confirms a hypothesis which was based upon metabolic research. However it is too early to upgrade the first "F" in the traditional adage that gallstone patients are "fair, fat, female, fertile and forty". Since both epidemiological and pathobiological evidence is scarce, the role of sun and/or (ultraviolet) light exposure and skin sensitivity in the aetiology of gallstones should be confirmed by further research.