Abstract A018: Inflammatory and insulinemic dietary and lifestyle patterns and incidence of endometrial cancer: The Multiethnic Cohort

Abstract BACKGROUND: Endometrial cancer (EC) is the most common gynecologic cancer and the fourth most common cancer among women in the U.S. The incidence of EC is increasing, particularly among racial/ethnic minority groups. Obesity is an established EC risk factor, and obesity-related inflammation and hyperinsulinemia may play an important role in EC etiology. We examined the association of five empirical dietary and lifestyle indices, which assess the inflammatory and insulinemic potentials of diet and were developed based on blood inflammatory biomarkers and insulin response, with the risk of EC in an ethnically diverse population. METHODS: We included 60,441 female participants from the Multiethnic Cohort (MEC) Study who were African American, Japanese American, Latino, Native Hawaiian, or White, aged 45-75 years at baseline in 1993-1996. Using a quantitative food frequency questionnaire, we derived the empirical dietary inflammatory pattern (EDIP), empirical dietary index for hyperinsulinemia (EDIH), empirical lifestyle index for hyperinsulinemia (ELIH), empirical dietary index for insulin resistance (EDIR), and empirical lifestyle index for insulin resistance (ELIR) scores. Multivariable Cox models adjusting for age, race/ethnicity, smoking status, body mass index (BMI), age at menarche, parity, menopausal status, oral contraceptive use, menopausal hormone therapy use, total energy intake, diabetes status, and family history of EC were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between each index (using quintiles) and EC risk. We examined associations stratified by race/ethnicity. RESULTS: We observed 1,328 incident EC cases over 1,291,333 person-years of follow-up. Women with higher ELIH had an increased risk of EC after adjusting for known EC risk factors (HRQ5vsQ1 = 2.58, 95% CI: 2.16-3.09; Ptrend <0.001). Similarly, higher ELIR was significantly associated with an increased risk of EC (HRQ5vsQ1 = 3.05, 95% CI: 2.49-3.72; Ptrend <0.001). Associations between ELIH (all Ptrend <0.003) and ELIR (all Ptrend <0.004) with EC were consistent across racial/ethnic groups. EDIP, EDIH and EDIR were not associated with EC risk in combined racial/ethnic groups, but African American women with the highest EDIP had an increased risk of EC (HRQ5vsQ1 = 1.58, 95% CI: 1.01-2.47, Ptrend = 0.03). CONCLUSIONS: In this ethnically diverse cohort, dietary and lifestyle patterns with higher inflammatory and insulinemic potential were associated with increased risk of EC. Reducing pro-inflammatory and hyperinsulinemic diet and lifestyle may reduce EC risk. Citation Format: Talar S. Habeshian, Songyi Park, David Conti, Lynne R. Wilkens, Loic Le Marchand, Veronica W. Setiawan. Inflammatory and insulinemic dietary and lifestyle patterns and incidence of endometrial cancer: The Multiethnic Cohort [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A018.