A cross-sectional study of more than 70,000 Asian Americans has found that the prevalence of obesity in Asian American subgroups varies substantially. These findings have important implications for directing and adapting obesity prevention and intervention strategies for Asian American populations. The study is published in Annals of Internal Medicine.

Obesity increases risk for cardiovascular and metabolic disease, and the risk occurs at lower body mass index (BMI) in Asian adults compared to White adults. This risk also varies within Asian subgroups, but most obesity estimates combine all Asian Americans into one group.

Researchers from Northwestern University Feinberg School of Medicine and the Centers for Disease Control and Prevention analyzed self-reported height, weight, and demographic data for more than more than 2.8 million adults who participated in the 2013–2020 Behavioral Risk Factor Surveillance System survey to quantify obesity prevalence in Asian American subgroups based on standard BMI standards (BMI ≥30 kg/m²) and those tailored to Asian populations (BMI ≥27.5 kg/m²).

Based on the standard threshold, Asian Americans as a combined demographic group had a 11.7% obesity prevalence compared to 39.% and 29.4% obesity prevalence in Black and in White adults, respectively. However, using a combined Asian American cohort and standard BMI threshold masked significant variance among subgroups, and underrecognized obesity among Asian American adults. By calculating obesity prevalence in a combined Asian American cohort using the modified BMI threshold, the prevalence of obesity was 22.4%, with a range from 13.2% in Chinese Americans to 28.7% in Filipino Americans. Identifying and addressing the Asian subgroup-specific factors that contribute to high obesity prevalence and differences in obesity prevalence among subgroups is necessary to mitigate the potential lifetime consequences of overweight and obesity.

An accompanying editorial from Annals deputy editor Christina Wee, MD, MPH argues that these findings highlight the limits of BMI as an indirect measure for body fat, because the correlations between BMI and adiposity vary substantially across populations and are influenced by factors such as age, sex, and ethnicity.

She highlights that this study also adds new complexity to existing research indicating that Asian Americans meet criteria for obesity at lower BMI thresholds than White Americans. She adds that while some guidelines have begun to acknowledge the influence of race and ethnicity on overweight and obesity thresholds, guidelines provide little guidance specific to Asian American populations. She notes that because clinicians and payers look to guidelines to guide practice and reimbursement for weight loss interventions, the lack of recommendations specific to patients of Asian descent puts them at risk for delayed treatment.