Prediagnostic Proinflammatory Dietary Potential Is Associated with All-Cause Mortality among African-American Women with High-Grade Serous Ovarian Carcinoma

BACKGROUND: Chronic inflammation is associated with ovarian carcinogenesis; yet, the impact of inflammatory-related exposures on outcomes has been understudied. OBJECTIVE: Given the poor survival of women diagnosed with ovarian cancer, especially African-Americans, we examined whether diet-associated inflammation, a modifiable source of chronic systemic inflammation measured by the dietary inflammatory index (DII), was associated with all-cause mortality among African-American women with ovarian carcinoma. METHODS: Data were available from 490 ovarian carcinoma patients enrolled in a population-based case-control study of African-American women with ovarian cancer, the African-American Cancer Epidemiology Study. Energy-adjusted DII (E-DII) scores were calculated based on prediagnostic dietary intake of foods alone or foods and supplements, which was self-reported using the 2005 Block Food Frequency Questionnaire. Cox proportional hazards regression was used to estimate risk of mortality overall and for the most common histotype, high-grade serous carcinoma. Additionally, we assessed interaction by age at diagnosis and smoking status. RESULTS: Women included in this study had a median age of 57 y, and the majority of women were obese (58%), had late-stage disease (Stage III or IV, 66%), and had high-grade serous carcinoma (64%). Greater E-DII scores including supplements (indicating greater inflammatory potential) were associated with an increased risk of mortality among women with high-grade serous carcinoma (HR(1-unit change): 1.08; 95% CI: 1.01, 1.17). Similar associations were observed for the E-DII excluding supplements, although not statistically significant (HR(1-unit change): 1.07; 95% CI: 0.97, 1.17). There was an interaction by smoking status, where the positive association with mortality was present only among ever smokers (HR(Quartile 4/Quartile 1): 2.36; 95% CI: 1.21, 4.60) but not among never smokers. CONCLUSIONS: Greater inflammatory potential of prediagnostic diet may adversely impact prognosis among African-American women with high-grade serous carcinoma, and specifically among ever smokers.