Hypertension, also called high blood pressure (BP), is a major risk factor for cardiovascular disease (CVD). Nearly one-third of all U.S. adults have hypertension, but only half of these cases are successfully controlled by medication or diet. The negative public health consequences are profound. American Indians (AIs) have disproportionate CVD morbidity and mortality, and they have higher burdens of hypertension, diabetes, and smoking than other races. Yet AIs are rarely represented in national studies on hypertension management. Most interventions targeting CVD have focused on reservation-based AIs, even though 71% of AIs live in urban areas. This urban population is an invisible minority, with high rates of disease and disability, and low rates of healthcare usage. Medication alone is suboptimal for controlling BP; a heart-healthy diet is preferable. Dietary Approaches to Stop Hypertension (DASH) is a high-impact lifestyle intervention for primary and secondary prevention of CVD that centers on a low-salt, low-fat diet emphasizing fresh fruits and vegetables. In a randomized trial, the DASH diet lowered systolic BP by 11.5 mm Hg in participants with clinical hypertension. However, the DASH diet never been tested in AIs. We therefore designed an 8-week DASH intervention to improve BP control in hypertensive urban AIs. Our American Indian Five Nuts and Beans Project (AI-5) includes culturally tailored DASH education that emphasizes low sodium intake, traditional Native foods, and maintaining healthy eating habits, plus a $30 weekly credit for home delivery of groceries that meet DASH guidelines. Home delivery is a creative solution to logistical barriers, such as limited access to fresh produce, that often deter residents of poor urban neighborhoods from maintaining a healthy diet. The control condition will receive printed educational materials and a $30 weekly credit for grocery delivery, with no purchasing restrictions. Our randomized trial will test AI-5 i a total of 400 adult AIs with inadequately controlled systolic BP (140-159 mmHg). We will recruit and randomize 200 participants from each of 2 urban clinics: one in Spokane, WA, the other in Oklahoma City, OK. Our primary outcome is systolic BP measured after the 8-week intervention and again 12 weeks later. Secondary outcomes are other modifiable CVD risk factors, risk scores for heart disease and stroke, and dietary habits. We will also conduct an embedded pilot study to inform future research on long-term sustainability and impact.
Our Specific Aims are to: 1) evaluate the effect of the AI-5 intervention on BP and secondary outcomes in adult AIs with poorly controlled hypertension, and 2) conduct a pilot study among 100 intervention participants after the intervention concludes by randomizing half to receive 6 weeks of dietician support (pilot intervention) and the other half to receive no further support (pilot control). We will collect BP data at 6 and 9 months post-baseline. This approach will have important public health implications and will inform efforts to export interventions for CVD and hypertension to other urban and rural AI groups.
Reducing intake of salt and fats can prevent cardiovascular disease and further the goals of Healthy People 2020. Sustainable, cost-effective dietary interventions are needed for high-risk populations such as urban American Indians. Our study adapts an existing heart-healthy diet for American Indians with high blood pressure, answering the American Heart Association's call for interventions that address household dietary practices.