Ethnicity-Based Body Mass Index Cutoffs for Type 2 Diabetes Risk

In order to prevent more cases of type 2 diabetes (T2D), cutoffs for body mass index (BMI) should be revised to reflect ethnicity-specific variation, according to the results of a population-based cohort study published in Lancet Diabetes and Endocrinology.

Electronic health record data from the Clinical Practice Research Datalink and Hospital Episodes Statistics from patients in the United Kingdom collected between 1990 and 2018 were assessed. New diagnoses of T2D were associated with ethnicity-specific trends in BMI.

A total of 1,472,819 records were included from patients aged mean 44.9 (standard deviation [SD], 17.9) years; 57.5% were women, mean BMI was 26.1 (SD, 5.1) kg/m², 90.6% were White, 5.2% were south Asian, 3.4% were Black, 0.7% were Chinese, and 0.7% were Arab.

At a median follow-up of 6.5 years, 6.6% (n=97,823) were diagnosed with T2D. The median age at diagnosis was 67 years (interquartile range [IQR], 57-76) among White (n=89,287), 55 years (IQR, 45-65) for south Asian (n=5632), 54 years (IQR, 47-65) for Black (n=2444), 60 years (IQR, 52-68) for Chinese (n=317), and 56 years (IQR, 47-64) for Arab (n=143) patients.

For an equivalent age- and sex-adjusted incidence of T2D at a BMI cutoff of 30.0 kg/m² among White populations, the investigators reported lower BMI cutoffs of 23.9 (95% CI, 23.6-24.0) kg/m² for south Asian, 28.1 (95% CI, 28.0-28.4) kg/m² for Black, 26.9 (95% CI, 26.7-27.2) kg/m² for Chinese, and 26.6 (95% CI, 26.5-27.0) kg/m² for Arab populations.

For an equivalent age- and sex-adjusted incidence of T2D at a BMI cutoff of 25.0 kg/m² among White populations, the investigators reported similar lower BMI cutoffs of 19.2 (95% CI, 18.9-19.3) kg/m² for south Asian, 23.4 (95% CI, 23.2-23.6) kg/m² for Black, 22.2 (95% CI, 22.0-22.4) kg/m² for Chinese, and 22.1 (95% CI, 21.8-22.0) kg/m² for Arab populations.

Adjusting for smoking and socioeconomic status did not significantly alter these cutoffs.

These data indicated that BMI cutoffs likely require ethnicity-specific revisions such that non-White populations can seek weight reduction care at a more appropriate point, potentially avoiding T2D onset.

Reference

Caleyachetty R, Barber TM, Mohammed NI, et al. Ethnicity-specific BMI cutoffs for obesity based on type 2 diabetes risk in England: a population-based cohort study. Lancet Diabetes Endocrinol. 2021;S2213-8587(21)00088-7. doi:10.1016/S2213-8587(21)00088-7