Abstract 18: Changes in Diet Quality Scores and Risk of Cardiovascular Disease Among Us Men and Women

Background: While adherence to several diet quality scores, including the Alternative Healthy Eating Index (AHEI), Alternative Mediterranean diet score (AMED), and Dietary Approach to Stop Hypertension (DASH), has been associated with lower risk of cardiovascular disease (CVD), little is known about how changes in these scores over time influence subsequent CVD risk. Objective: To evaluate the association between 4-y changes in three diet quality scores (AHEI, AMED and DASH) and subsequent risk of CVD among women and men in the Nurses’ Health Study I and Health Professionals Follow-up Study. Methods: We followed up 50,195 women in the Nurses’ Health Study (1986-2010) and 29,547 men in the Health Professionals Follow-up Study (1986-2010). AHEI, AMED and DASH were defined using data obtained from validated food frequency questionnaires updated every 4-y. Time-dependent and baseline Cox proportional hazards regression models were used to calculate hazard ratios (HR) with adjustment for age, family history of CVD, race, baseline diet quality, changes in smoking status, and initial and changes in other lifestyle factors (physical activity, alcohol intake, total energy intake). Outcome was defined as the number of confirmed incident cases of CVD (total coronary heart disease and stroke). Results across cohorts were pooled by an inverse variance-weighted, random-effect meta-analysis. Results: During 1,397,871 person-years of follow-up, we documented 11,542 incident CVD cases. Compared with individuals whose diet quality remained relatively stable (no change) in each 4-y period, those with the greatest improvements (11-22%) in diet quality had a 7-8% lower risk of CVD in the subsequent 4-y period [pooled HR (95% CI): AHEI: 0.92(0.87, 0.99); AMED: 0.93 (0.85, 1.02); DASH: 0.93, (0.87, 0.99); all P-trend<0.05]. A 20 % increase in diet scores was associated with 3-9% lower risk of CVD (AHEI: 0.91 (0.86, 0.97); AMED: 0.97 (0.94, 0.99); DASH: 0.94 (0.90, 0.98). Increasing the diet scores (12-22%) from baseline to the first 4-y follow-up was associated with a lower risk of CVD during the next 20 years of follow-up [7% (1%, 12%) for AHEI and 9% (3%, 14%) for AMED]. On the other hand, a decrease in DASH score (16%) was associated with 8% (2%, 15%) higher risk of CVD over 20 years. Conclusions: Improving adherence to diet quality scores over time is associated with significantly lower risk of CVD, both in the short-term and long-term. Our results provide novel evidence that modest improvement in diet quality over time confers benefits for CVD prevention.