Fast food price, diet behavior, and cardiometabolic health: Differential associations by neighborhood SES and neighborhood fast food restaurant availability in the CARDIA study.

Little research has addressed whether neighborhood context influences associations between fast food price, diet, and cardiometabolic health. We investigated these associations using 25 years of Coronary Artery Risk Development in Young Adults (CARDIA) study data (n=4,469, observations=21,134). We found a negative association between fast food price and consumption, with stronger inverse associations in more (vs. less) deprived neighborhoods [3rd tertile: β=-0.68 (95% CI: (-0.85, -0.51); 1st tertile: β=-0.22 (95% CI: -0.42, -0.02); p-interaction-0.002], and a similar association for BMI [3rd tertile: β=-1.34 (95% CI: -1.54, -1.14); 1st tertile: β=-0.45 (95% CI: -0.66, -0.25); p-interaction<0.001], but not insulin resistance [3rd tertile: β=-0.07 (95% CI: -0.24, 0.09); 1st tertile: β=0.09 (95% CI: -0.08, 0.26); p-interaction=0.40]. We observed no modification of fast food price by fast food availability. Future research on obesity disparities should consider potential differences in the association between fast food prices and health outcomes across neighborhood socioeconomic levels.