Cardiovascular Risk High Among Some Normal Weight Minorities

Nicola M. Parry, DVM

April 03, 2017

Nearly one third of individuals from several racial/ethnic minority groups with a healthy body weight have a higher risk for heart disease and diabetes, a new cross-sectional study of US adults shows.

Unjali P. Gujral, PhD, from Emory University, Atlanta, Georgia, and colleagues published the results of their study online April 3 in the Annals of Internal Medicine.

"Compared with whites, all racial/ethnic minority groups had a statistically significantly higher prevalence of [metabolic abnormality but normal weight] (MAN), which was not explained by demographic, behavioral, or ectopic fat measures," the authors write.

"Although the [US Preventive Services] Task Force recommends earlier screening in racial/ethnic minority populations, testing for cardiometabolic abnormalities in normal-weight and underweight members of these groups also may be an important consideration."

According to the authors, although excess body weight is clearly associated with an increased risk for cardiometabolic diseases, some normal weight individuals also have elevated cardiometabolic risk. The relationship between weight status and cardiometabolic risk also varies with race/ethnicity.

However, data about the prevalence of MAN among some at-risk minority groups, including East and South Asians, are lacking.

Dr Gujral and colleagues therefore aimed to compare the prevalence of MAN among members of five racial/ethnic minority groups.

They performed a cross-sectional analysis of two large cohort studies, including data from 2622 white, 803 Chinese American, 1893 African-American, and 1496 Hispanic participants from the Multi-Ethnic Study of Atherosclerosis (MESA), as well as 803 South Asian individuals in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study.

The overall prevalence of normal weight and obesity varied with race/ethnicity. Normal-weight prevalence was highest among whites (32.3%) and Chinese Americans (40.2%), whereas obesity prevalence was highest among African Americans (45.4%) and Hispanics (38.6%).

In addition, 29.1% of the participants with normal weight had the MAN phenotype, whereas 35.8% of those with obesity were metabolically normal.

MAN prevalence also varied significantly with race/ethnicity. "Compared with whites, the prevalence of MAN was approximately 100% greater in South Asians, 50% in Chinese and African Americans, and 80% in Hispanics," the authors write. Prevalence was 21.0% (95% confidence interval [CI], 18.4% - 23.9%) in whites, 32.2% (CI, 27.3% - 37.4%) in Chinese Americans, 31.1% (CI, 26.3% - 36.3%) in African Americans, 38.5% (CI, 32.6% - 44.6%) in Hispanics, and 43.6% (CI, 36.8% - 50.6%) in South Asians.

Among all individuals with MAN, South Asians were also significantly younger than individuals of other minority groups with MAN.

However, adjusting for variables such as age, sex, education, smoking status, daily caloric intake, and hepatic fat attenuation did not account for these differences in MAN prevalence.

The researchers also estimated the body mass index (BMI) values at which the expected numbers of metabolic abnormalities among the racial/ethnic minority groups would equal those among whites. For a MAN prevalence equivalent to that in whites with a BMI of 25 kg/m2, they found corresponding BMI values were lower in all minority groups.

These findings therefore suggest that using a BMI criterion alone is a poor indicator of cardiometabolic risk in most of these populations, and may prevent clinicians from identifying cardiometabolic abnormalities in many patients from racial/ethnic minority groups. The authors emphasize that race/ethnicity alone may be a better predictor of cardiometabolic risk in these populations.

"Future research is needed to identify the prospective associations between MAN and incident diabetes and cardiovascular disease in various racial/ethnic groups," Dr Gujral and colleagues conclude.

This study was supported by grants from the National Institutes of Health, including the National Center for Research Resources and National Heart, Lung, and Blood Institute. The authors have disclosed no relevant financial relationships.

Ann Intern Med. Published online April 3, 2017. Abstract

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