Dietary intakes of vitamins A, C, and E and risk of melanoma in two cohorts of women

Within the two Nurses' Health Study cohorts of US women, we examined whether higher intakes of vitamin C, vitamin E, retinol, or individual tocopherols or carotenoids are associated with a lower risk of melanoma. We confirmed 414 cases of invasive melanoma among over 162000 Caucasian women aged 25-77 years during more than 1.6 million person-years of follow-up. Diet was measured every 4 years with a food frequency questionnaire and supplement use was reported every 2 years. Several measures of sun sensitivity were assessed and included in proportional hazards models. We found that vitamins A, C, E and their individual components were not associated with a lower risk of melanoma. Only retinol intake from foods plus supplements appeared protective within a subgroup of women who were otherwise at low risk based on nondietary factors (relative risk (RR) = 0.39, 95% confidence interval (CI) 0.22-0.71 for ≥ 1800 vs <400 μg day^-1, P for linear trend = 0.01). Contrary to expectation, we observed higher risks of melanoma with greater intakes of vitamin C from food only (RR = 1.43, 95% CI 1.01-2.00 for ≥ 175 vs <90 mg day^-1, P for linear trend = 0.05) and a significant positive dose-response with frequency of orange juice consumption (P = 0.008). Further research is needed to determine whether another component in foods such as orange juice may contribute to an increase in risk.