Cardiometabolic Abnormalities Among Normal-Weight Persons From Five Racial/Ethnic Groups in the United States: A Cross-sectional Analysis of Two Cohort Studies

Abstract

Background: The relationship between body weight and cardiometabolic disease may vary substantially by race/ethnicity.

Objective: To determine the prevalence and correlates of the phenotype of metabolic abnormality but normal weight (MAN) for 5 racial/ethnic groups.

Design: Cross-sectional analysis.

Setting: 2 community-based cohorts.

Participants: 2622 white, 803 Chinese American, 1893 African American, and 1496 Hispanic persons from MESA (Multi-Ethnic Study of Atherosclerosis) and 803 South Asian participants in the MASALA (Mediators of Atherosclerosis in South Asians Living in America) study.

Measurements: Prevalence of 2 or more cardiometabolic abnormalities (high fasting glucose, low high-density lipoprotein cholesterol, and high triglyceride levels and hypertension) among normal-weight participants was estimated. Correlates of MAN were assessed by using log-binomial models.

Results: Among normal-weight participants (n = 846 whites, 323 Chinese Americans, 334 African Americans, 252 Hispanics, and 195 South Asians), the prevalence of MAN was 21.0% (95% CI, 18.4% to 23.9%) in whites, 32.2% (CI, 27.3% to 37.4%) in Chinese Americans, 31.1% (CI, 26.3% to 36.3%) in African Americans, 38.5% (CI, 32.6% to 44.6%) in Hispanics, and 43.6% (CI, 36.8% to 50.6%) in South Asians. Adjustment for demographic, behavioral, and ectopic body fat measures did not explain racial/ethnic differences. After adjustment for age, sex, and race/ethnicity-body mass index (BMI) interaction, for the equivalent MAN prevalence at a BMI of 25.0 kg/m2 in whites, the corresponding BMI values were 22.9 kg/m2 (CI, 19.5 to 26.3 kg/m2) in African Americans, 21.5 kg/m2 (CI, 18.5 to 24.5 kg/m2) in Hispanics, 20.9 kg/m2 (CI, 19.7 to 22.1 kg/m2) in Chinese Americans, and 19.6 kg/m2 (CI, 17.2 to 22.0 kg/m2) in South Asians.

Limitation: Cross-sectional study design and lack of harmonized dietary data between studies.

Conclusion: Compared with whites, all racial/ethnic minority groups had a statistically significantly higher prevalence of MAN, which was not explained by demographic, behavioral, or ectopic fat measures. Using a BMI criterion for overweight to screen for cardiometabolic risk may result in a large proportion of racial/ethnic minority groups being overlooked.

Primary funding source: National Institutes of Health.

Figure 1. Prevalence of BMI categories and metabolic status, by race/ethnicity

Top. Prevalence of BMI category, by race/ethnicity. Error bars are 95% CIs. Bottom. Prevalence of metabolic normality, by BMI category and race/ethnicity. Metabolically abnormal was defined as the presence of ≥2 of the following components: decreased high-density lipoprotein cholesterol levels (<1.036 mmol/L [<40 mg/dL] in men or <1.295 mmol/L [<50 mg/dL] in women or use of lipid-lowering medication), elevated triglyceride levels (fasting triglyceride levels ≥1.7 mmol/L [≥150 mg/dL]), elevated glucose levels (fasting plasma glucose level ≥5.6 mmol/L [≥100 mg/dL] or use of glucose-lowering medication), and high blood pressure (≥130/85 mm Hg or use of antihypertensive medication). Error bars are 95% CIs. BMI = body mass index.

Figure 2. Race/ethnicity-specific BMI values associated with MAN compared with whites with a BMI of 25 kg/m²

MAN was defined as a BMI of 18.5 to 24.9 kg/m² for white, African American, and Hispanic participants or a BMI of 18.5 to 22.9 kg/m² for South Asian and Chinese American participants and ≥2 of the following components: decreased high-density lipoprotein cholesterol levels (<1.036 mmol/L [<40 mg/dL] in men or <1.295 mmol/L [<50 mg/ dL] in women or use of lipid-lowering medication), elevated triglyceride levels (fasting triglyceride levels ≥1.7 mmol/L [≥150 mg/ dL]), elevated glucose levels (fasting plasma glucose level ≥5.6 mmol/L [≥100 mg/dL] or use of glucose-lowering medication), and high blood pressure (≥130/85 mm Hg or use of antihypertensive medication). To obtain BMI values for South Asians, African Americans, Hispanics, and Chinese Americans that would result in an expected MAN prevalence approximately equal to that among whites with a BMI of 25 kg/m², based on a Poisson model for MAN, a proportional odds model was fit for the prevalence of MAN in white participants with a BMI of 25 kg/m², with group-specific 4-knot restricted cubic splines in BMI, adjusting for sex and a 4-knot restricted cubic spline in age. A search algorithm then was used to find the BMI values for each of the other 4 groups that resulted in approximately the same expected prevalence of MAN. BMI = body mass index; MAN = metabolic abnormality but normal weight.