Sun exposure and risk of epithelial ovarian cancer

Associations between sun exposure (a primary source of vitamin D) and risk of ovarian cancer have been inconsistent. Furthermore, studies have not investigated whether sun exposure at different periods in the lifetime of a person results in differences in risk associations, and little is known about differences according to histological subtype. Using a population-based case-control study of 1,334 non-Hispanic white women diagnosed with epithelial ovarian cancer in western Washington State between 2002 and 2009 and 1,679 non-Hispanic white controls, we assessed the relation of epithelial ovarian cancer with constitutional pigmentation characteristics, sun exposure behaviors, and an index of ultraviolet (UV) exposure based on residential history. Information was collected through in-person interviews. Logistic regression was used to compute odds ratios, 95 % confidence intervals, and trend p values (P-trend). We noted no association with residence-based measures of UV exposure or self-reported sun exposure, either over the lifetime or within specific age intervals. Also, we observed little evidence of association between constitutional pigmentation characteristics and risk, save for a suggestion of increased risk among women who reported increased ability to suntan upon prolonged sun exposure (P-trend = 0.03). Results from this study suggest that sun exposure has little influence on the risk of epithelial ovarian cancer. Additional studies in populations with a wider gradient of sun exposure may yet be warranted.