Abstract A73: Obesity, weight gain, and ovarian cancer risk in African American women

Background: There is growing evidence that obesity increases ovarian cancer risk. However, little is known about the impact of body fatness and weight gain in African American women, the racial/ethnic group with the highest prevalence of obesity according to national data.

Methods: We evaluated the association between ovarian cancer risk and body mass index (BMI) at age 18, recent BMI, and weight gain since age 18 years in the African American Cancer Epidemiology Study (AACES), an ongoing, population-based case-control study of ovarian cancer in African American women in 11 geographical areas in the US. Cases (n=492) and age and site matched controls (n=696) were identified through rapid case ascertainment and random-digit-dialing, respectively. A computer-assisted telephone interview was used to collect information on ovarian cancer risk factors, including self-reported height, weight at age 18, and weight one year before diagnosis/interview. Multivariable logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI), adjusting for potential covariates, including age, region, education, parity, tubal ligation, oral contraceptive use, age at menarche, menopausal status, and family history of breast/ovarian cancer.

Results: Sixty two percent of the cases and fifty six percent of the controls were obese (BMI≥30). Obese women had elevated ovarian cancer risk, particularly for recent BMI≥40 compared to BMI <25 (OR=1.72, 95% CI: 1.12, 2.66; p for trend: 0.03). No relationship was observed for BMI at age 18. However, there was a strong association with weight gain since age 18 years (OR: 1.68; 95% CI: 1.19-2.39; p for trend: 0.006) comparing the highest to lowest quartile. In stratified analyses by menopausal status, the association with recent BMI persisted in postmenopausal women (OR: 1.94; 95% CI: 1.14-3.30), but was weak and not statistically significant in pre-menopausal women (OR: 1.28; 95% CI: 0.56-2.92). Excluding postmenopausal hormone therapy users essentially did not change results. There was also a strong association with weight gain among postmenopausal women with 14% increased risk per 10 kg of weight gain (OR: 1.14: 95% CI: 1.05-1.23).

Conclusion: Our findings suggest that obesity and excessive adult weight gain may increase ovarian cancer risk in post-menopausal African American women.

Citation Format: Elisa V. Bandera, Bo Qin, Anthony J. Alberg, Jill Barnholtz-Sloan, Melissa Bondy, Michelle Cote, Ellen Funkhouser, Edward Peters, Ann Schwartz, Paul Terry, Patricia G. Moorman, Joellen Schildkraut. Obesity, weight gain, and ovarian cancer risk in African American women. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr A73.