The Dietary Inflammatory Index Is Associated with Colorectal Cancer Risk in the Multiethnic Cohort

Abstract

Diet is known to influence systemic inflammation, a recognized risk factor for colorectal cancer (CRC). Studies in ethnically diverse populations that examine the association between dietary inflammatory potential and CRC incidence are limited. We used the Dietary Inflammatory Index to clarify the relation between the inflammatory potential of diet and CRC incidence across racial/ethnic groups. We hypothesized that proinflammatory diets would be associated with an increased risk of CRC, and that these associations may differ across racial/ethnic groups. The Multiethnic Cohort (MEC) follows a prospective study design. It includes 190,963 white, African-American, native Hawaiian, Japanese-American, and Latino men and women aged 45-75 y at recruitment and followed over 20 y. Participants completed a food frequency questionnaire from which energy-adjusted Dietary Inflammatory Index (E-DII) scores were computed and categorized into quartiles. CRC incidence was documented through linkage to cancer registry programs. Cox proportional hazards regression was used to estimate HRs and 95% CIs, adjusting for known or expected CRC risk factors. Among all participants, more-proinflammatory diets (highest quartile compared with lowest quartile) were associated with an increased risk of CRC (HR: 1.21; 95% CI: 1.11, 1.32). However, the effect size was larger for men (HR: 1.28; 95% CI: 1.13, 1.45) than for women (HR: 1.16; 95% CI: 1.02, 1.33), although the interaction term for sex was not statistically significant (interaction = 0.17). When stratified by race/ethnicity, the association was significantly different between groups for men (interaction = 0.01), although not for women (interaction = 0.20). Significant associations with HRs ranging from 2.33 to 1.04 were observed in white, Japanese-American, and Latino men, and native Hawaiian women. Overall, more-proinflammatory diets, as identified by the E-DII, were associated with increased CRC risk in MEC participants across racial/ethnic groups. This study adds to the evidence suggesting that diets with high proinflammatory potential may increase CRC risk.

Publication Title

The Journal of nutrition

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