Associations between sun exposure and other lifestyle variables in Swedish women

Sun exposure is associated with risk of several chronic diseases including cancer. The study aim is to investigate whether sun behaviors are related to other lifestyle risk factors of cancer. We analyzed data collected in 2003–2004 by self-completed questionnaire from 34,402 Swedish women aged 40–61 years, who comprised 70% of a cohort of originally recruited from a population registry in 1991–1992 (n = 49,259). Participants were asked about annual number of sunburns and annual number of weeks of swimming and sunbathing during 1991–2002, solarium use during 1991–1998 and current sunscreen use. Compared to non-drinkers, the prevalence ratio (95% CI) in women who drank >10 g of alcohol per day was 1.64 (1.49, 1.81) for having >1 sunburn per year, 1.39 (1.29, 1.51) for swimming and sunbathing >2.5 weeks per year and 1.55 (1.41, 1.70) for using a solarium >1 time per 2 months, adjusting for demographic and lifestyle variables. Tobacco smokers were less likely to report sunburn and to use sunscreen, and more likely to sunbath and use solaria, compared with non-smokers. Physical activity was associated positively with swimming and sunbathing, and with the separate use of solaria and sunscreens, but not with number of sunburns. The lifestyle variables that explained most of the variation in sun behavior were alcohol and smoking. Our results suggest that alcohol consumption and tobacco smoking are potential lifestyle confounders which should be adjusted in studies investigating the association that sun and/or solarium exposure may have with risk of several cancer sites.