A clinic-based case-control study was conducted to determine the association between
vitamin supplement use and risk of
basal cell carcinoma (BCC) of the skin. The subjects were 131 patients with histopathologically confirmed primary BCC and 200
cancer-free controls with non-premalignant skin disorders. Use of any
vitamins (mainly multivitamins and
vitamins A, C, and E) was associated with reduced risk of BCC. After controlling for age, sex, cigarette smoking, number of lifetime severe
sunburns, and skin actinic elastosis, regular
vitamin supplementation was associated with a significantly reduced risk of BCC (odds ratio (OR) = 0.3; 95% confidence interval (CI) = 0.2-0.06). The
ORs decreased as the regularity (p < 0.001) and daily doses of supplement used increased, especially for
vitamins A (p < 0.005) and E (p < 0.005).
Vitamin supplementation was not associated with alterations in cellular DNA repair. These results, however, cannot be considered conclusive because of the relatively low participation rates (131/830 for cases and 200/1406 for controls) due to the requirement of blood donation and more rigorous studies are needed to clarify the effect of supplemental
vitamins, particularly of
vitamins A and E, on the risk of BCC of the skin.