CASE-CONTROL STUDY OF SUN EXPOSURE AND SQUAMOUS-CELL CARCINOMA OF THESKIN

We conducted a case-control study of sun exposure and squamous cell ca rcinoma (SCC) of the skin within a population-based, longitudinal stud y of skin cancer. Cases had histopathologically confirmed SCC. Subject s were interviewed about their lifetime sun exposure, including exposu re to the site of the SCC (sites for controls were assigned randomly). Analysis was restricted to 132 cases and 1,031 controls born in Austr alia and with no ancestors from southern Europe. The total site-specif ic exposure was strongly related to risk of SCC; the odds ratio increa sed to a maximum of 3.3 at 65,000 hr of exposure before falling slight ly. Site-specific exposure during childhood and adolescence was more s trongly associated with SCC than exposure during adulthood. An intermi ttent pattern of weekly sun exposure was not associated with SCC and t he odds ratios for hours of exposure on vacation were close to unity. The number of blistering sunburns to the site was positively associate d with SCC. Use of sunscreens and hats showed inconsistent effects. Su n exposure, especially during childhood and adolescence, increases the risk of SCC. The pattern of exposure appears to be unimportant, despi te the association with sunburn, which may simply be an indicator of t he skin's sensitivity to sunlight. (C) 1998 Wiley-Liss, Inc.