The Dietary Inflammatory Index Is Associated with Colorectal Cancer Risk in the Multiethnic Cohort.
Background: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.Objectives: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.Methods: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.Results: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 (P-interaction = 0.17). When stratified by race/ethnicity, the association was significantly different between groups for men (P-interaction = 0.01), although not for women (P-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.Conclusions: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.
School of Public Health, University of Memphis, Memphis, TN; bharmon1@memphis.edu.
Brook E
BE
Harmon
Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, SC.
Michael D
MD
Wirth
University of Hawaii Cancer Center, Honolulu, HI.
Carol J
CJ
Boushey
University of Hawaii Cancer Center, Honolulu, HI.
Lynne R
LR
Wilkens
School of Public Health, University of Memphis, Memphis, TN.
Emma
E
Draluck
Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, SC.
Nitin
N
Shivappa
Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, SC.
Susan E
SE
Steck
South Carolina College of Pharmacy, University of South Carolina, Columbia, SC; and.
Lorne
L
Hofseth
Cancer Center, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA.
Christopher A
CA
Haiman
University of Hawaii Cancer Center, Honolulu, HI.
Loic
L
Le Marchand
Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, SC.
James R
JR
Hébert
D001741:Black or African American; D000368:Aged; D001213:Asian; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000208:ethnology* / Q000209:etiology*; D004032:Diet / Q000009:adverse effects*; D004034:Diet Surveys; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
cancer stage; chronic inflammation; colon cancer; racial/ethnic groups; rectal cancer