Dairy, calcium, vitamin D and ovarian cancer risk in African-American women

Background: No previous study has evaluated the associations of dairy products, lactose, calcium and vitamin D with the risk of ovarian cancer in African-American women, who are known to have high mortality from the disease, as well as to be at risk for calcium and vitamin D deficiency. Methods: We evaluated these associations among 490 ovarian cancer cases and 656 age-and site-matched controls of African-American descent recruited into the African American Cancer Epidemiology Study, a population-based case-control study in 11 geographical areas in the US. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: An increased ovarian cancer risk was observed for whole milk consumption and lactose intake (highest quartile vs lowest: OR = 1.97, 95% CI: 1.25-3.10; P-trend: 0.008). Calcium intake was associated with a decreased risk of ovarian cancer (OR = 0.51, 95 CI%: 0.30-0.86; P-trend: 0.009), but vitamin D intake was not. Longer sun exposure in summer months was found to predict a lower risk (OR = 0.71, 95% CI: 0.51-0.99; P-trend: 0.049). Conclusions: Our findings suggest that a high-calcium, low-lactose diet, and sun exposure in summer months may reduce the risk of ovarian cancer in African-American women.