BMI Association With Diabetes Risk Varies Across Low- and Middle-Income Countries

By Lisa Rapaport

July 23, 2021

(Reuters Health) - The optimal BMI threshold for diabetes screening may vary across low- and middle-income countries, results from a new study of the association between BMI and diabetes suggest.

Researchers examined data from nationally-representative surveys of 685,616 individuals residing in 57 low- and middle-income countries in Latin America and the Caribbean; Europe and central Asia; east, south, and southeast Asia; sub-Saharan Africa, Middle East and north Africa; and Oceania. All the surveys provided individual-level data on height, weight, and diabetes biomarkers such as point-of-care fasting capillary glucose, plasma equivalents, a laboratory-based measurement of fasting plasma glucose, and HbA1c.

The overall prevalence of diabetes was 9.3%, while the prevalence of overweight was 27.2% and the prevalence of obesity was 21.0%. The mean BMI was 25.8, and, in pooled analysis, the risk of diabetes was significantly higher in both men (RR 1.41) and women (RR 1.43) who had a BMI in the "upper normal" range (BMI 23.0 to 29.9) compared with the "normal" range (BMI 18.5 to 22.9).

In addition, the threshold for screening based on the BMI range associated with increased diabetes risk varied considerably by region, from as low as 23.8 for men in east, south, and southeast Asia to as high as 28.3 for women in the Middle East and north Africa and in Latin America and the Caribbean.

"As a clinical community, and certainly as a wider global public health community, we should acknowledge that the relationship between body mass index and diabetes is likely not a one size fits all," said senior study author Dr. Jennifer Manne-Goehler, of the Division of Infectious Diseases at the Brigham and Women's Hospital and the Medical Practice Evaluation Center at Massachusetts General Hospital in Boston.

The study results suggest that clinicians and the public health community may need to consider whether to tailor screening for diabetes to different BMI thresholds for certain segments of the population or include other body composition measures to improve diabetes risk assessment, Dr. Manne-Goehler said by email.

"In some settings, this may mean screening a person for diabetes at a body weight that, for their height, would traditionally have been characterized as 'normal,' and expanding diabetes screening to younger populations in certain contexts," Dr. Manne-Goehler said.

One limitation of the study is that identification of individuals with diabetes was in some instances based on a single glucose measurement, researchers note in The Lancet. In addition, it's possible that some individuals had their weight impacted by developing diabetes or by taking medications to treat diabetes, the study team also points out.

Even so, variability in the association between BMI and diabetes risk has been observed in previous studies, and has been attributed in part to ethnic difference in body mass distribution, said Dr. Simeon Pierre Choukem of the faculty of medicine and pharmaceutical sciences at the University of Dschang in Cameroon, who coauthored a commentary accompanying the study.

"What is surprising here isn't the observed variability per se, but the threshold at which the risk of developing diabetes increases steeply, especially among sub-Saharan Africans," Dr. Choukem said by email.

SOURCE: and The Lancet, online July 17, 2021.