Food intake and risk of basal cell carcinoma in an 11-year prospective study of Australian adults

Background/Objective: Experimental studies suggest that dietary factors may influence skin cancer risk, but there have been few human studies of diet and basal cell carcinoma (BCC), the most common type of skin cancer. The objective was to prospectively investigate the association between food intake and incidence of BCC skin cancers. Subjects/Methods: At baseline in 1992, 1056 adults in a subtropical Australian community completed a validated food-frequency questionnaire from which we estimated the intake of 15 food groups, selected based on hypothesized associations in the literature. Between 1992 and 2002, incident, histologically confirmed BCCs were recorded in terms of number of persons newly affected by BCC, as well as BCC tumor counts. Results: Intakes of the food groups were not associated with the incidence of persons affected by BCC. However, there was a borderline positive association between intake of eggs and incidence of BCC tumors (highest vs lowest tertile adjusted relative risk (RR) 1.5; 95% confidence interval (CI): 1.0-2.2; P for trend = 0.06). A borderline inverse association with potato intake (highest vs lowest tertile RR 0.7; 95% CI: 0.4-1.0, P for trend = 0.06) disappeared after exclusion of three subjects with more than 10 BCCs. Conclusion: Despite some suggestive evidence that egg and potato consumption may be associated with BCC tumor incidence, there are no plausible grounds for considering these as truly causal rather than chance associations. This study provides little evidence for a role of food intake in BCC prevention.