Community Intervention to Improve CVD Risk Factor Control in Young American Indians

Cardiovascular disease (CVD) incidence in American Indians is more than two-fold higher than the age-matched United States (US) population, and significantly associated with elevated lipids/lipoproteins and glucose levels. Through systematic surveillance conducted by the Strong Heart Study (SHS), the largest and longest running study of CVD in American Indians, we report that elevated lipid/lipoprotein prevalence for participants <20, 20-29, and 30-39 years old was 55.2%, 73.6%, and 78.0%, respectively. In addition, we report that American Indians under 40 years old with elevated LDL cholesterol had a three-fold greater independent risk of subclinical atherosclerosis five (5) years later and/or incident, clinical CVD 20 years later. Although statin therapy is effective for dyslipidemia, the rates of use are low among American Indians, with less than 50% of young SHS participants with primary hypercholesterolemia receiving treatment. In addition, the high diabetes prevalence (8%) in young American Indians contributes to high rates of CVD, where incidence of atherosclerosis was 41.3 per 1,000 person-years in diabetics compared to 16.3 per 1,000 person-years in non-diabetics (p<0.001). These elevated lipid/lipoprotein and glucose levels may be due to limited health care access and lifestyle factors such as nutrition, physical activity, sleep hygiene, and social determinants of health (SDOH), including social support. As a result, there is a critical need to measure these factors and include them in a culturally appropriate intervention to control lipid/lipoprotein and glucose levels and thereby reduce CVD.

The long-term goal of this research, which aligns with the NHLBI's strategic goal to "reduce human disease," is to reduce incident CVD risk in American Indians. Our overall objective is to determine the effectiveness of a culturally appropriate intervention, designed with American Indian involvement, to control lipid/lipoprotein and glucose levels. To achieve this objective, we will determine the effectiveness of a guided intervention. Before determining the intervention effectiveness, we will use a community-engaged approach and conduct focus groups asking participants to offer recommendations for a modified version of the Balance Study that we conducted with older (mean age=52 years) American Indians in Oklahoma, 2008-2012. Subsequently, we will recruit 360 American Indians, 18-39 years old, with elevated lipid/lipoprotein or glucose levels. Among this group, we will assess baseline CVD risk factors and then randomly assign them to either a self-managed control group receiving health care referrals and educational materials or to an 18-month guided intervention group, incorporating: 1) community health workers (CHW) to reduce health care access barriers and 2) a multidimensional component focusing on nutrition, physical activity, and CVD risk factor education during at least six (6) quarterly in-person meetings. Based on the Balance Study and SHS, we formulated the central hypothesis that health care access, nutrition, physical activity, and CVD risk factor education jointly contribute to lipid/lipoprotein and glucose control. Therefore, the rationale for the proposed research is to include these components in an intervention targeting lipid/lipoprotein and glucose management. Given our experience with American Indian communities recruiting and designing interventions for the SHS, we are well-positioned to conduct this research, with the following Specific Aims:

Aim 1: (A) To work with CHWs, healthcare workers, community leaders, and community members to adapt a culturally relevant CVD risk factor intervention based on the Balance Study for American Indians, 18-39 years old. (B) To assess the acceptability of the adapted intervention among American Indians, 18-39 years old from communities participating in the Strong Heart Study in southwestern Oklahoma. We will work with members of the community to adapt a lifestyle intervention for younger populations that was previously used in older populations of American Indians, titled the Balance Study. Then we will conduct focus groups among American Indians who are 18-29 or 30-39 to determine the acceptability of adapted intervention among these groups.

Aim 2: To determine if the adapted 18-month guided intervention is more effective than self-management at lowering LDL-C or glucose levels, among American Indians, with serum LDL-C ≥100 mg/dL and/or fasting plasma glucose ≥126 mg/dL who are 18-39 years old from communities participating in the Strong Heart Study in southwestern Oklahoma. Hypothesis: American Indians, 18-39 years old, randomized to the guided intervention, will have at least a 10% reduction in LDL-C and/or glucose levels after 18 months.

The proposed research will determine the effectiveness of an intervention that uses the CHW model to target health care access, nutrition, physical activity, and CVD risk factor education within the young adult American Indian population. The expected outcomes include the refinement of a culturally appropriate CVD risk factor reduction intervention and the reduction of LDL-C and glucose levels in young American Indians with elevated CVD risk. This study will decrease the disproportionately high lipid/lipoprotein and glucose levels that are significantly predictive of incident CVD in young American Indians.

Inclusion criteria

• American Indians
• 18-39 years old
• Members of the tribal communities that participate in the Strong Heart Study in southwestern Oklahoma
• Only one person per household will be eligible

Exclusion criteria

• Are unwilling or unable to follow the intervention, which includes modifying current nutritional intake and participating in the proposed physical activity program
• Are taking lipid-/lipoprotein-lowering or diabetes medication
• Are already participating in a diabetes or CVD risk factor reduction program
• Are pregnant or plan to become pregnant in the next 18 months
• Are not English speaking
• Are institutionalized
• Have underlying disease with a life-expectancy of less than 2 years (e.g., cancer or end stage renal disease).