The association of overall diet quality with BMI and waist circumference by education level in Mexican men and women.

OBJECTIVE: The present study evaluated the association of two measures of diet quality with BMI and waist circumference (WC), overall and by education level, among Mexican men and women. DESIGN: We constructed two a priori indices of diet quality, the Mexican Diet Quality Index (MxDQI) and the Mexican Alternate Healthy Eating Index (MxAHEI), which we examined relative to BMI and WC. We computed sex-specific multivariable linear regression models for the total sample and by education level. SETTING: Mexico. PARTICIPANTS: Mexican men (n 954) and women (n 1356) participating in the Mexican National Health and Nutrition Survey 2012. RESULTS: Total dietary scores were not associated with BMI in men and women, but total MxDQI was inversely associated with WC in men (-0·10, 95 % CI -0·20, -0·004 cm). We also found that some results differed by education level in men. For men with the lowest education level, a one-unit increase in total MxDQI and MxAHEI score was associated with a mean reduction in BMI of 0·11 (95 % CI -0·18, 0·04) and 0·18 (95 % CI -0·25, -0·10) kg/m2, respectively. Likewise, a one-unit increase in total MxDQI and MxAHEI score was associated with a mean change in WC of -0·30 (95 % CI -0·49, -0·11) and -0·53 (95 % CI -0·75, -0·30) cm, respectively, in men with the lowest level of education. In women, the association of diet quality scores with BMI and WC was not different by education level. CONCLUSIONS: Our findings suggest that a higher diet quality in men with low but not high education is associated with lower BMI and WC.