Obesity reclassification under the ADA 2026 criteria and elevated measured blood pressure in adults aged 20–59 years: an analysis of 45 population-based surveys

Objective To compare obesity reclassification under the 2026 American Diabetes Association (ADA) criteria versus the WHO body mass index (BMI) criterion and its association with elevated measured blood pressure in adults aged 20–59 years.Research design and methods We analyzed 45 population-based surveys using harmonized anthropometry, blood pressure, and sampling weights. Prevalences and paired reclassification differences incorporated released survey-design information. Modified Poisson models adjusted for age, sex, and survey fixed effects. Sensitivity analyses varied survey weighting, Asian-threshold assignment, and retention.Results Among 137 600 participants, mean survey-specific obesity prevalence was 28.2% with WHO and 53.6% with ADA. The mean increase was 25.4 percentage points (median 25.9; range 4.4–41.2); heterogeneity was substantial (I²=99.1%; 95% prediction interval 3.3–47.4). ADA had higher sensitivity for elevated measured blood pressure (69.8% vs 42.5%) but lower specificity (51.4% vs 76.2%) and positive predictive value (31.3% vs 37.3%); balanced accuracy was 60.6% vs 59.3%. Central-adiposity reclassification was associated with a higher prevalence of elevated measured blood pressure than unreclassified overweight (adjusted prevalence ratio 1.34; 95% CI 1.24 to 1.46), with similar findings across sensitivity analyses.Conclusions In adults aged 20–59 years, the ADA criteria identify an additional adiposity-defined subgroup with a higher prevalence of elevated measured blood pressure. Reporting waist measures alongside BMI and survey-specific reclassification estimates can strengthen cardiometabolic surveillance and inform locally proportionate prevention.