Nearly a third of adults with normal body mass index (BMI) measurements had cardiometabolic abnormalities, according to a cross-sectional study of two cohort cohorts.
African Americans, Chinese Americans and Hispanics with normal BMIs had a significantly higher rate of cardiometabolic abnormalities compared with whites. The racial and ethnic differences remained even after adjusting for demographic, behavioral and ectopic body fat measures.
Lead researcher Unjali P. Gujral, PhD, of Emory University in Atlanta, and colleagues published their results online in the Annals of Internal Medicine on April 3.
The researchers examined data from the MESA (Multi-Ethnic Study of Atherosclerosis) and MASALA (Mediators of Atherosclerosis in South Asians Living in America) studies. They compared 803 South Asian participants from MASALA with 2,622 white, 803 Chinese American, 1,893 African American and 1,496 Hispanic participants from MESA.
The MESA study took place between July 2000 and July 2002 and enrolled participants 45 to 84 years old. Researchers tracked participants’ physical activity, fasting serum glucose, cholesterol, dietary intake and other information.
The MASALA study enrolled participants who were 40 to 84 years old between October 2010 and March 2013. The participants completed food frequency questionnaires, and researchers used the same protocols as the MESA study for seated blood pressure and anthropometry. They also measured participants’ waist circumference and collected blood samples.
The researchers assessed the following cardiometabolic abnormalities: high fasting glucose, low high-density lipoprotein (HDL) cholesterol and high triglyceride levels and hypertension. They defined low HDL cholesterol as a level lower than 40 mg/dL in men or lower than 50 mg/dL in women or the use of any lipid-lowering medications. They defined elevated triglycerides as a fasting triglyceride level of 150 mg/dL or greater.
In addition, they classified elevated glucose as a fasting plasma glucose level of 100 mg/dL or greater or the use of glucose-lowering medications. Further, they defined high blood pressure as 130/85 mm Hg or greater or any use of antihypertensive medications.
The researchers considered a normal BMI as 18.5 to 24.9 kg/m2 for white, African American and Hispanic participants and 18.5 to 22.9 kg/m2 for South Asian and Chinese American participants.
Of the participants, 25.6 percent were considered normal weight, 41.5 percent were considered overweight and 32.9 percent were considered obese.
The researchers defined the metabolic abnormality but normal weight (MAN) phenotype as the prevalence of two or more cardiometabolic abnormalities in normal weight individuals.
Overall, the prevalence of the MAN phenotype was 29.1 percent, including 21 percent in whites, 32.2 percent in Chinese Americans, 31.1 percent in African Americans, 38.5 percent in Hispanics and 43.6 percent in South Asians.
After the researchers adjusted for age, sex and race/ethnicity–BMI interaction, they found that for the equivalent MAN prevalence at a BMI of 25 kg/m2 in whites, the corresponding BMI values were 22.9 kg/m2 in African Americans, 21.5 kg/m2 in Hispanics, 20.9 kg/m2 in Chinese Americans and 19.6 kg/m2 in South Asians.
The researchers acknowledged a few potential limitations of their analysis, including that the studies had differences in the timing of data collection, which could have led to differences in the prevalence of overweight and obese individuals. The studies also used different food-frequency questionnaires. In addition, the studies were not nationally representative, which means the results might not be generalizable to younger people or South Asians and Chinese Americans born in the U.S.
“The key message for clinicians is that using overweight and obesity as the main criteria to screen for high blood pressure, high glucose, high triglycerides, or low HDL cholesterol will likely miss a substantial number of people who have high cardiometabolic risk but are of normal weight,” Gujral said in a news release. “Therefore, while the United States Preventive Services Task Force recommends screening at younger ages in racial/ethnic minority groups, testing for cardiometabolic abnormalities in normal-weight and underweight members of these groups may also be an important consideration.”
Executive Editor
Tim Casey joined TriMed Media Group in 2015 as Executive Editor. For the previous four years, he worked as an editor and writer for HMP Communications, primarily focused on covering managed care issues and reporting from medical and health care conferences. He was also a staff reporter at the Sacramento Bee for more than four years covering professional, college and high school sports. He earned his undergraduate degree in psychology from the University of Notre Dame and his MBA degree from Georgetown University.