A priori-defined diet quality indexes and risk of type 2 diabetes: the Multiethnic Cohort

Abstract Aims/hypothesis Dietary patterns have been associated with the incidence of type 2 diabetes, but little is known about the impact of ethnicity on this relationship. This study evaluated the association between four a priori dietary quality indexes and risk of type 2 diabetes among white individuals, JapaneseAmericans and Native Hawaiians in the Hawaii component of the Multiethnic Cohort. Methods After excluding participants with prevalent diabetes and missing values, the analysis included 89,185 participants (11,217 cases of type 2 diabetes). Dietary intake was assessed at baseline with a quantitative food frequency questionnaire designed for use in the relevant ethnic populations. Sex-and ethnicity-specific HRs were calculated for the Healthy Eating Index-2010 (HEI-2010), the Alternative HEI-2010 (AHEI-2010), the Alternate Mediterranean Diet Score (aMED) and the Dietary Approaches to Stop Hypertension (DASH). Results We observed significant inverse associations between higher DASH index scores and risk of type 2 diabetes in white men and women, as well as in Japanese-American women and Native Hawaiian men, with respective risk reductions of 37%, 31%, 19% and 21% (in the highest compared with the lowest index category). A higher adherence to the AHEI-2010 and aMED diet was related to a 13-28% lower risk of type 2 diabetes in white participants but not in other ethnic groups. No significant associations with risk of type 2 diabetes were observed for the HEI-2010 index. Conclusions/interpretation The small ethnic differences in risk of type 2 diabetes associated with scores of a prioridefined dietary patterns may be due to a different consumption pattern of food components and the fact that the original indexes were not based on diets typical for Asians and Pacific Islanders