Racial differences in population attributable risk for epithelial ovarian cancer in the OCWAA Consortium

Background The causes of racial disparities in epithelial ovarian cancer (EOC) incidence remain unclear. Differences in the prevalence of ovarian cancer risk factors may explain disparities in EOC incidence among African American (AA) and White women. Methods We used data from four case-control studies and three case-control studies nested within prospective cohorts in the Ovarian Cancer in Women of African Ancestry Consortium to estimate race-specific associations of ten known or suspected EOC risk factors using logistic regression. Using the Bruzzi method, race-specific population attributable risks (PAR) were estimated for each risk factor individually and collectively, including groupings of exposures (reproductive factors and modifiable factors). All statistical tests were two-sided. Results Among 3,244 White EOC cases and 9,638 controls and 1,052 AA EOC cases and 2,410 controls, AA women had a statistically significantly higher PAR (false discovery rate (FDR) P < .001) for first-degree family history of breast cancer (PAR = 10.1%, 95% CI = 6.5% to 13.7%) compared to White women (PAR = 2.6%, 95% CI = 0.8% to 4.4%). After multiple test correction, AA women had a higher PAR than White women when evaluating all risk factors collectively (PAR = 61.6%, 95% CI = 48.6% to 71.3% vs. PAR = 43.0%, 95% CI = 32.8% to 51.4%, respectively; FDR P = .06) and for modifiable exposures, including BMI, oral contraceptives, aspirin, and body powder (PAR = 36.0%, 95% CI = 21.0% to 48.8% vs. PAR = 13.8%, 95% CI = 4.5% to 21.8%, respectively; FDR P = .04). Conclusions Collectively, the selected risk factors accounted for slightly more of the risk among AA than White women, and interventions to reduce EOC incidence that are focused on multiple modifiable risk factors may be slightly more beneficial to AA women than White women at risk for EOC.