One-year follow-up study of blood pressure and dietary patterns in dietary approaches to stop hypertension (DASH)–sodium participants

Background We conducted a 12-month follow-up study on participants in the Dietary Approaches to Stop Hypertension (DASH)–Sodium trial to determine the impact of the DASH diet and 150, 100, or 50 mmol/day of sodium after discontinuation of the feeding intervention. Methods Upon completion of the trial, 56 of the 113 participants at the clinical center at Duke University entered a longitudinal observational study. Measurements including 24-h ambulatory systolic and diastolic blood pressure (BP), weight, and 24-h urinary electrolytes were obtained at 1, 6, and 12 months after completion of the DASH-Sodium trial. Block food frequency questionnaires were completed at the 12-month visit. Linear mixed-effects regression models were used to analyze the effect of the diet and sodium intake on longitudinal changes in BP during the final feeding period. Results The DASH participants significantly increased their intakes of fruits or juices and vegetables at 12 months. Control participants had no change in DASH food group intake. Both groups increased sodium intake. Among control participants, systolic and diastolic BP increased 5.33 (95% confidence interval [CI] 0.28, 10.37) and 3.20 mm Hg (95% CI 0.25, 6.16), respectively. Among DASH participants, systolic and diastolic BP increased 3.12 (95% CI −0.44, 6.68) and 0.79 mm Hg (95% CI −1.15, 2.72), respectively. There was a significant effect of the final sodium level by diet on the change in SBP over time (P = .04 for three-way interaction among diet, time of visit, and sodium). Conclusions After the feeding intervention, DASH diet participants ate more fruits/vegetables and had sustained reductions in BP despite increased sodium intake.