Trends in osteoarthritis burden and the role of body mass index among older U.S. adults, 1999–2023: a NHANES and GBD analysis

Abstract

Objective: To examine the association between body mass index (BMI) and osteoarthritis (OA) among U.S. adults aged ≥55 years and to characterize national temporal trends, geographic patterns, and future burden projections. Methods: This multi-source study integrated NHANES (1999–2023) and GBD data. Multivariable logistic regression assessed BMI–OA associations with sex-stratified, subgroup, and interaction analyses. NHANES survey-weighted temporal trends in obesity and OA prevalence were examined across cycles. GBD estimates were used to evaluate OA incidence, prevalence, disability-adjusted life years, age-standardized rates, geographic variation, decomposition analyses, and projections through 2040. Results: Among 7,857 participants, 1,054 had OA. Each 1 kg/m² increase in BMI was independently associated with 5% higher odds of OA after full adjustment, with a dose–response gradient; associations were stronger among women, older adults, and lower-income participants. NHANES temporal trends showed that obesity prevalence rose from 29.3% to 41.8% (2011–2020) while OA prevalence remained stable (27.8–32.3%), consistent with GBD findings. Incident OA cases increased substantially from 1999 to 2023, driven by population growth and ageing; age-standardized rates changed modestly. Projections indicate persistently high burden through 2040. Conclusion: Higher BMI was independently associated with increased odds of OA, with a clear dose–response gradient. NHANES and GBD data consistently showed that population growth and ageing, rather than rising age-specific risk, have driven the increase in OA burden, while rising obesity may portend additional future burden. Targeted weight management and risk-stratified prevention are warranted for ageing populations.