High-Quality Diets Associate With Reduced Risk of Colorectal Cancer: Analyses of Diet Quality Indexes in the Multiethnic Cohort

BACKGROUND & AIMS: Healthy eating patterns assessed by diet quality indexes (DQIs) have been related to lower risk of colorectal cancer-mostly among whites. We investigated the associations between 4 DQI scores (the Healthy Eating Index 2010 [HEI-2010], the Alternative Healthy Eating Index 2010 [AHEI-2010], the alternate Mediterranean diet score [aMED], and the Dietary Approaches to Stop Hypertension score) and colorectal cancer risk in the Multiethnic Cohort. METHODS: We analyzed data from 190,949 African American, Native Hawaiian, Japanese American, Latino, and white individuals, 45 to 75 years old, who entered the Multiethnic Cohort study from 1993 through 1996. During an average 16 years of follow-up, 4770 invasive colorectal cancer cases were identified. RESULTS: Scores from all 4 DQIs associated inversely with colorectal cancer risk; higher scores associated with decreasing colorectal cancer risk (all P's for trend <= .003). Associations were not significant for AHEI-2010 and aMED scores in women after adjustment for covariates: for the highest vs lowest quintiles, the hazard ratio for the HEI-2010 score in men was 0.69 (95% confidence interval [CI], 0.59-0.80) and in women was 0.82 (95% CI, 0.70-0.96); for the AHEI-2010 score the hazard ratio in men was 0.75 (95% CI, 0.65-0.85) and in women was 0.90 (95% CI, 0.78-1.04); for the aMED score the hazard ratio in men was 0.84 (95% CI, 0.73-0.97) and in women was 0.96 (95% CI, 0.82-1.13); for the Dietary Approaches to Stop Hypertension score the hazard ratio in men was 0.75 (95% CI, 0.66-0.86) and in women was 0.86 (95% CI, 0.75-1.00). Associations were limited to the left colon and rectum for all indexes. The inverse associations were less strong in African American individuals than in the other 4 racial/ethnic groups. CONCLUSIONS: Based on an analysis of data from the Multiethnic Cohort Study, high-quality diets are associated with a lower risk of colorectal cancer in most racial/ethnic subgroups.