Concordance with DASH diet and blood pressure change: Results fromthe Framingham Offspring Study (1991-2008)

Background: Concordance with the Dietary Approaches to Stop Hypertension (DASH) diet has been shown to reduce blood pressure (BP) in short-term intervention studies, but the long-term impact is unclear. We evaluated the association of DASH diet concordance with BP trajectories and incidence of hypertension, in 2187 men and women (mean age 52.5 years at baseline) participating in the Framingham Offspring cohort. Method: Diet and BP were assessed from 1991 to 2008, with a median follow-up time of 13.4 years. DASH scores (ranging from 0 for worst to 10 for best concordance with DASH diet) were calculated by summing 10 food components that comprise the DASH diet pattern, including fruits and vegetables, low-fat dairy products, lean meat, and plant-based protein. Mixed-effect and Cox regression models were applied, to assess the association of DASH diet concordance with BP longitudinal change and with incidence of hypertension, respectively. All analyses were adjusted for age, sex, smoking status, history of diabetes, BMI, and physical activity. Result: Overall, SBP increased by 0.34mmHg and DBP by 0.10mmHg annually, in the Framingham Offspring cohort. Every unit increase in the DASH score resulted in a modest increase in SBP of 0.054 mmHg/year (P=0.028). No associations were observed between DASH diet concordance and DBP or incidence of hypertension. Conclusion: Long-term concordance with the DASH diet was not associated with a decreasing BP trajectory over time, or with decreased incidence of hypertension, in this population of middle-aged adults.