DASH Diet May Help Prevent Heart Failure in Women

Laurie Barclay, MD

May 21, 2009

May 21, 2009 — Women who followed the Dietary Approaches to Stop Hypertension (DASH) diet had lower rates of heart failure, according to the results of a prospective observational cohort study reported in the May 11 issue of the Archives of Internal Medicine.

"The...DASH diet may contribute to prevention of heart failure in some cases because it effectively reduced blood pressure and low-density lipoprotein cholesterol levels in clinical trials," write Emily B. Levitan, ScD, of Beth Israel Deaconess Medical Center in Boston, Massachusetts, and colleagues. "This diet features high intake of fruits, vegetables, low-fat dairy products and whole grains, resulting in high potassium, magnesium, calcium and fiber consumption, moderately high protein consumption and low total and saturated fat consumption....We hypothesized that diets consistent with the DASH diet would be associated with a lower incidence of heart failure."

The study cohort consisted of 36,019 participants in the Swedish Mammography Cohort who were aged 48 to 83 years and did not have heart failure, diabetes mellitus, or myocardial infarction at baseline. Food frequency questionnaires were used to evaluate diet, and a score was created to determine adherence to the DASH diet by ranking the intake of DASH diet components and 3 other scores based on food and nutrient guidelines. Body mass index was calculated as weight in kilograms divided by height in meters squared.

Using the Swedish inpatient and cause-of-death registers from January 1, 1998, to December 31, 2004, the investigators calculated rate ratios of hospitalization or death associated with heart failure from Cox proportional hazards models. During this 7-year study, heart failure developed in 443 women. The rate of heart failure was 37% lower in women in the top quartile of the DASH diet score, after adjustment for age, physical activity, energy intake, educational level, family history of myocardial infarction, cigarette smoking, postmenopausal hormone use, living alone, hypertension, high cholesterol concentration, body mass index, and incident myocardial infarction.

Across quartiles of the DASH diet score, rate ratios were 1 [Reference], 0.85 (95% confidence interval [CI], 0.66 - 1.11), 0.69 (95% CI, 0.54 - 0.88), and 0.63 (95% CI, 0.48 - 0.81; P trend < .001). Findings were similar with use of the guideline-based scores.

"Greater consistency with the DASH diet as measured using food-frequency questionnaires was associated with lower rates of heart failure in middle-aged and elderly women living in Sweden," the study authors write. "In the present study, the DASH score based on ranking components of diet was a stronger predictor of HF [heart failure] than were other scores that were based on absolute intake."

Limitations of this study include inability to determine the cause or subtype of heart failure, lack of generalizability to less severe cases of heart failure treated exclusively on an outpatient basis, lack of representation of populations with known high rates of hypertensive heart disease and heart failure, measurement of hypertension by self-report, lack of validation of DASH diet scores against an external standard, and exposure misclassification resulting from use of food frequency questionnaires.

Grants from the Swedish Research Council/Committee for Infrastructure maintained the cohort. A grant from the Swedish Foundation for International Cooperation in Research and Higher Education and a grant from the National Institutes of Health supported this study. The study authors have disclosed no relevant financial relationships.

Arch Intern Med. 2009;169:851-857.

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