Fred K Tabung

Inflammatory and insulinemic dietary patterns and risk of endometrial cancer among US women

Abstract Background Although unopposed estrogen exposure is considered a major driver of endometrial carcinogenesis, chronic inflammation and insulin resistance and hyperinsulinemia are also major endometrial cancer risk factors. However, it is unclear whether diets with inflammatory or insulinemic potential are associated with risk of endometrial cancer. Methods We followed 48 330 women from the Nurses’ Health Study (1984-2016) and 85 426 women from the Nurses’ Health Study II (1989-2017). Using food frequency questionnaires, we calculated repeated measures of empirical dietary inflammatory pattern (EDIP) and empirical dietary index for hyperinsulinemia (EDIH) scores, which characterize the potential of the whole diet to modulate circulating biomarkers of inflammation or C-peptide, respectively. We used multivariable-adjusted Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for type I endometrial cancer risk. Results We documented 1462 type I endometrial cancer cases over 2 823 221 person-years of follow-up. In the pooled multivariable-adjusted analyses, women in the highest compared with lowest quintiles were at higher risk of type I endometrial cancer (EDIP HRQ5vsQ1 = 1.46, 95% CI = 1.24 to 1.73; Ptrend < .001; EDIH HRQ5vsQ1 = 1.58, 95% CI = 1.34 to 1.87; Ptrend < .001). Additional adjustment for body mass index attenuated the associations (EDIP HR = 1.03, 95% CI = 0.87 to 1.22; EDIH HR = 1.01, 95% CI = 0.85 to 1.21), and mediation analyses showed that body mass index may explain 60.4% (95% CI = 37.4% to 79.6%; P < .001) and 71.8% (95% CI = 41.0% to 90.4%; P < .001) of the association of endometrial cancer with EDIP and EDIH, respectively. Conclusions In this large cohort study, higher dietary inflammatory and insulinemic potential were each associated with increased endometrial cancer incidence, and this association may be almost entirely mediated by adiposity.

Associations of Dietary Patterns with Colorectal Adenomas in the Prostate, Lung, Colorectal, and Ovarian Cancer Cohort

Abstract Background: Most colorectal cancers arise from adenomas, and although insulinemic and inflammatory dietary patterns have been associated with colorectal cancer risk, these dietary patterns have not been studied in relation to adenoma risk. Methods: Using data from 21,192 participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer screening cohort, we calculated the Empirical Dietary Index for Hyperinsulinemia (EDIH), Empirical Dietary Inflammatory Pattern (EDIP), and overall dietary quality measured via the Healthy Eating Index (HEI-2015), from food frequency questionnaires (FFQ). In multivariable-adjusted logistic regression, we investigated associations of these dietary indices with adenoma (any adenoma, advanced adenoma, n = 19,493) and recurrent adenoma (n = 1,699). Results: EDIH was not associated with adenoma or advanced adenoma but was marginally associated with recurrent adenoma. The OR (95% CI) comparing highest (lowest insulinemic) versus lowest (most hyperinsulinemic) quintiles was 0.76 (0.55–1.05) after multivariable adjustment including BMI. EDIP and HEI-2015 were not associated with any of the three outcomes. Conclusions: In the PLCO cohort, we did not observe substantial associations between dietary patterns and risk of colorectal adenomas. Impact: Pending confirmation in larger prospective studies, our findings suggest that these dietary patterns may not substantially affect colorectal cancer risk via the adenoma–carcinoma sequence.