Melanoma risk in relation to use of sunscreen or other sun protection methods.

BACKGROUND Epidemiologic evidence supporting sunscreen for melanoma prevention is limited to one small trial; case-control studies report conflicting results. Sunscreen usage patterns or alternative sun protection methods have rarely been studied in relation to melanoma. METHODS In a population-based case-control study, participants (1,167 cases; 1,101 controls) reported for each decade year of age outdoor activity-related sunscreen use, sunscreen patterns (SPF15+, amount, skin coverage, reapplication, routine use), and use of other sun protection methods (like hats, long-sleeved shirts, staying in the shade). Scores were averaged across activities and/or decades; scores in the most recent two decades were used to classify individuals as non-, inconsistent- or optimal users. Adjusted mean score differences between cases and controls, and ORs and 95% CIs for melanoma among optimal-, inconsistent- versus nonusers were calculated. RESULTS Mean scores for sunscreen, sunscreen patterns or other sun protection methods were low, but higher among controls than cases for SPF15+ sunscreen (P = 0.03) and other sun protection methods (P = 0.006). Adjusted ORs for optimal use of sunscreen and most sunscreen patterns were null or relatively weak, except for routine sunscreen (adjusted OR = 0.44, 95% CI: 0.23-0.86). Optimal use of other sun protection methods was inversely associated with melanoma (adjusted OR = 0.59, 95% CI: 0.44-0.78). CONCLUSIONS Optimal use of routine sunscreen or other sun protection methods were most strongly associated with decreased melanoma risk; results are limited by the small number of subjects who used sunscreen routinely and lack of specificity regarding other sun protection methods. IMPACT Both improving sunscreen practices and encouraging sun avoidance strategies may be important for melanoma prevention.