Vitamin and carotenoid intake and risk of squamous cell carcinoma of the skin.

Our objective was to examine prospectively the intake of vitamins A (including retinol and total vitamin A), C and E; folate; total carotene; and several individual carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin and lutein/zeaxanthin) in relation to incidence of SCC of the skin in 2 large cohorts of men and women. We used a prospective cohort study design with up to 14 years of follow-up in women and 10 years in men. Diet was measured with FFQs every 2-4 years; cases of SCC of the skin were ascertained on biennial questionnaires and confirmed by medical records. Participants were female nurses and male health professionals, from the Nurses' Healthy Study and the Health Professionals Follow-up Study in the United States, without a history of any cancer in 1982 (n = 85,944 women) and 1986 (n = 43,867 men). Follow-up response was achieved for over 90% of potential person-years. Relative risks and 95% confidence intervals for development of SCC of the skin are reported. We recorded 369 cases of SCC in women and 305 cases in men. After multivariate adjustment for various known behavioral, sun-exposure and sun-sensitivity risk factors for SCC, there were no significant inverse associations between these dietary factors and SCC incidence. No evidence was found that vitamins A, C and E; folate; or carotenoids play an important protective role against incident SCC.