Herman A. Taylor

The burden of cardiovascular risk associated with obesity disproportionately affects African Americans and little is known about ethnic/racial differences in the relationship of obesity to cardiometabolic risk. This report assesses whether obesity is similarly associated with cardiometabolic risk factors in African Americans and whites of European ancestry. Cross‐sectional observational data from the Jackson Heart Study (JHS) and the Framingham Heart Study (FHS) were compared. This analysis uses participants aged 35–74 years with BMI >18.5 kg/m², and free of prevalent cardiovascular disease (CVD), from the initial JHS clinical examination (2000–2004) and the FHS Offspring (1998–2001) and Third Generation (2002–2005) cohorts. Participants were evaluated for the presence of lipid abnormalities, hypertension, and diabetes. Overall, 4,030 JHS (mean age 54 years, 64% women) and 5,245 FHS (mean age 51 years, 54% women) participants were available for analysis. The prevalence of all risk factors except high triglycerides and low high‐density lipoprotein (HDL) was substantially higher in JHS (all P < 0.001) and BMI was associated with increasing prevalence of most CVD risk factors within each race. For diabetes mellitus, hypertension, and low HDL, steeper relationships to BMI were observed in FHS than in JHS (P values <0.001–0.016). There were larger proportional increases in risk factor prevalence with increasing BMI in whites than in African Americans. The higher prevalence rates of cardiometabolic risk factors at nearly all levels of BMI in African Americans, however, suggest that additional factors contribute to the burden of CVD risk in African Americans.

African Americans have an increased incidence and worse prognosis with chronic kidney disease (CKD - estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m2) than their counterparts of European-descent. Inflammation has been related to renal disease in non-Hispanic whites, but there are limited data on the role of inflammation in renal dysfunction in African Americans in the community.

OBJECTIVE—Health of African Americans is seriously threatened by unremitting epidemics of diabetes and cardiovascular disease (CVD). However, the role of metabolic syndrome in the African-American population has not been investigated widely. This study examined the prevalence of metabolic syndrome and assessed its cross-sectional relationship to CVD in the Jackson Heart Study (JHS) cohort. RESEARCH DESIGN AND METHODS—A total of 5,302 participants aged ≥21 years who were recruited at baseline during 2000–2004 were analyzed for this study. Adjusted odds ratios (ORs) were estimated in a logistic regression analysis for coronary heart disease (CHD) and cerebrovascular disease (CBD) in those with and without coexisting metabolic syndrome. Diabetic participants were excluded. RESULTS—Among those aged 35–84 years, metabolic syndrome prevalence was 43.3% in women and 32.7% in men. Elevated blood pressure (70.4%), abdominal obesity (64.6%), and low HDL cholesterol (37.2%) were highly prevalent among those with metabolic syndrome. Prevalence rates for CVD, CHD, and CBD were 12.8, 8.7, and 5.8%, respectively. After adjustment for age and sex, metabolic syndrome was associated with increased age- and sex-adjusted ORs for CVD (OR 1.7 [95% CI 1.4–2.1]), CHD (1.7 [1.4–2.2]), and CBD (1.7 [1.3–2.3]) compared with those without CVD, CHD, or CBD. CONCLUSION—Metabolic syndrome prevalence in the JHS is among the highest reported for population-based cohorts worldwide and is significantly associated with increased ORs for CVD, CHD, and CBD. Abdominal obesity, increased blood pressure, and low HDL cholesterol (without triglyceride elevation) are surprisingly prominent. A high prevalence of low HDL emerges as a leading contributor to metabolic syndrome among African Americans in this large African-American cohort.

The JHS, therefore, is a response to American health disparities that employs community-driven research strategies that promise impact in the near and the long term. It includes scientific investigations in the tradition of Framingham and other large-scale epidemiologic studies that may confirm or revise our understanding of key factors in the current epidemic. The future health of the nation compels us to produce future cohorts of scientists that are prepared to sustain any gains made and to press on toward the long-term goal of eliminating CVD from all segments of American society. The dearth of scientists from the population most afflicted by CVD means that we must make inclusion of such scientists in the scientific workforce a priority. Through programs described in this issue, the JHS is taking steps toward these goals. Ultimately, the science and the scientists that emerge from the JHS will produce health benefits that transcend geography, ethnicity, and the current era of population research.