Association between diet quality and incident cardiovascular disease stratified by body mass index

Objective: Diet quality is a significant contributor to cardiovascular disease (CVD) development given its substantial influence on important downstream CVD mediators such as weight. However, it is unclear if there are additional pathways between diet quality and incident CVD independent of weight. We sought to determine if higher diet quality was associated with lower CVD risk stratified by BMI categories. Methods: Prospective cohort data from the Lifetime Risk Pooling Project (LRPP) was analyzed. Diet data from 6 US cohorts were harmonized. The alternative Healthy Eating Index-2010 (aHEI-2010) score was calculated for each participant. Within each cohort, participants were divided into aHEI-2010 quintiles. The primary outcome of interest was composite incident CVD event including coronary heart disease, stroke, heart failure, and CVD death. Cox regression analysis was performed separately for three BMI strata: 18.5–24.9, 25–29.9, and ≥ 30 kg/m². Results: A total of 30,219 participants were included. During a median follow-up of 16.2 years, there were a total of 7,021 CVD events. An inverse association between aHEI-2010 score and incident CVD was identified among participants who were normal weight (comparing highest quintile with lowest quintile: adjusted hazard ratio [95% confidence interval] 0.57 [0.50 – 0.66]) and among participants with overweight (0.69 [0.61 – 0.77]). aHEI-2010 score was not associated with CVD among participants with obesity (0.97 [0.84 – 1.13]). Conclusions: Among adults in the United States, higher diet quality as measured by aHEI-2010 was significantly associated with lower risk of incident CVD among individuals with normal weight and overweight but not obesity.