Cataract and ovarian carcinoma: is the vitamin D hypothesis alive?

BACKGROUND The major health benefit of exposure to solar UV radiation is the production of vitamin D, which is implicated in protection against several human cancers, including ovarian carcinoma. On the other hand, solar UV radiation is a recognized risk factor for cataract. METHODS This population-based case-control study of 709 women with primary invasive ovarian carcinoma and 1,101 controls examined the association of ovarian carcinoma risk with self-reported history of cataract as an indicator of high long-term exposure to UV radiation. ORs and 95% confidence intervals (CI) were estimated using multivariate logistic regression models. RESULTS Among controls, older age (P < 0.0001), history of type 2 diabetes (P = 0.04), and skin cancer (P = 0.03) were significant cataract risk predictors. A history of cataract, reported by 14% of cases and 17% of controls, was significantly associated with a reduced ovarian carcinoma risk (OR = 0.6; 95% CI, 0.4-0.8; P = 0.002). No heterogeneity was observed by tumor histology, stage, grade, study site, body mass index, or other ovarian cancer risk factors (P > 0.16). CONCLUSION These findings add indirect evidence to the hypothesis that lifetime vitamin D exposure may be inversely associated with risk of ovarian carcinoma. IMPACT The study suggests some potential new avenues for research. Additional studies are needed to further investigate the potential behavioral and biologic factors that might influence association of cataract with ovarian cancer.