Adherence to a DASH-Style Diet and Risk of Coronary Heart Disease and Stroke in Women

Abstract

The Dietary Approaches to Stop Hypertension (DASH) diet has been shown to lower blood pressure, but little is known about its long-term effect on cardiovascular end points. Our objective was to assess the association between a DASH-style diet adherence score and risk of coronary heart disease (CHD) and stroke in women. In this prospective cohort study, diet was assessed 7 times during 24 years of follow-up (1980-2004) with validated food frequency questionnaires. A DASH score based on 8 food and nutrient components (fruits, vegetables, whole grains, nuts and legumes, low-fat dairy, red and processed meats, sweetened beverages, and sodium) was calculated. Lifestyle and medical information was collected biennially with a questionnaire. The Cox proportional hazard model was used to adjust for potential confounders. The study population comprised 88,517 female nurses aged 34 to 59 years without a history of cardiovascular disease or diabetes in 1980. The main outcome measures were the numbers of confirmed incident cases of nonfatal myocardial infarction, CHD death, and stroke. We documented 2129 cases of incident nonfatal myocardial infarction, 976 CHD deaths, and 2317 [corrected] cases of stroke. After adjustment for age, smoking, and other cardiovascular risk factors, the relative risks of CHD across quintiles of the DASH score were 1.0, 0.99, 0.86, 0.87, and 0.76 (95% confidence interval, 0.67-0.85) (P<.001 for trend). The magnitude of risk difference was similar for nonfatal myocardial infarction and fatal CHD. The DASH score was also significantly associated with lower risk of stroke (multivariate relative risks across quintiles of the DASH score were 1.0, 0.92, 0.91, 0.89, and 0.82) (P=.002 for trend). Cross-sectional analysis in a subgroup of women with blood samples showed that the DASH score was significantly associated with lower plasma levels of C-reactive protein (P=.008 for trend) and interleukin 6 (P=.04 for trend). Adherence to the DASH-style diet is associated with a lower risk of CHD and stroke among middle-aged women during 24 years of follow-up.