Genital powder use and risk of epithelial ovarian cancer in the ovarian cancer in women of African Ancestry consortium

Background: Genital powder use is more common among African-American women; however, studies of genital powder use and ovarian cancer risk have been conducted predominantly in White populations, and his to type-specific analyses among African- American populations are limited. Methods: We used data from five studies in the Ovarian Cancer in Women of African Ancestry consortium. Participants included 620 African-American cases, 1, 146 African-American controls, 2, 800 White cases, and 6, 735 White controls who answered questions on genital powder use prior to 2014. The association between genital powder use and ovarian cancer risk by race was estimated using logistic regression. Results: The prevalence of ever genital powder use for cases was 35.8% among African-American women and 29.5% among White women. Ever use of genital powder was associated with higher odds of ovarian cancer among African-American women [OR = 1.22; 95% confidence interval (CI) = 0.97-1.53] and White women (OR = 1.36; 95% CI = 1.19-1.57). In African-American women, the positive association with risk was more pronounced among high-grade serous tumors (OR = 1.31; 95% CI = 1.01-1.71) than with all other histotypes (OR=1.05; 95% CI=0.75-1.47). In White women, a significant association was observed irrespective of histotype (OR = 1.33; 95% CI = 1.12-1.56 and OR = 1.38; 95% CI = 1.15-1.66, respectively). Conclusions: While genital powder use was more prevalent among African-American women, the associations between genital powder use and ovarian cancer risk were similar across race and did not materially vary by histotype. Impact: This is one of the largest studies to date to compare the associations between genital powder use and ovarian cancer risk, overall and by histotype, between African-American and White women.