Regional and National Burden of Osteoarthritis Attributable to High Body Mass Index in Western Pacific Countries and Territories, 1990-2023: A Systematic Analysis for the Global Burden of Disease Study 2023.

Background: Osteoarthritis (OA) is one of the most prevalent degenerative joint diseases worldwide and is characterized by chronic pain and functional decline, particularly among older adults. High body mass index (BMI) is a key modifiable risk factor associated with OA and may influence OA burden through biomechanical and metabolic pathways. This study aimed to assess the regional and national burden of OA attributable to high BMI in the Western Pacific Region from 1990 to 2023. Methods: This ecological secondary data analysis used Global Burden of Disease (GBD) 2023 data to quantify the burden of OA across 31 countries in the Western Pacific Region. Combined OA was defined as the sum of the burdens of hip and knee OA, and site-specific estimates for hip and knee OA were reported separately. Within the GBD comparative risk assessment framework, we estimated risk-attributable OA burden using the relevant population attributable fractions. We estimated years lived with disability (YLDs) using the GBD modeling pipeline and applied age standardization to enable comparisons across populations. We quantified uncertainty by generating 250 model draws to obtain mean estimates and 95% uncertainty intervals (UIs), defined as the 2.5th and 97.5th percentiles of the draws. Results: In 2023, the Western Pacific Region was estimated to have 1.55 million YLDs attributable to high BMI for combined OA, a 287% increase since 1990. The age-standardized YLD rate for combined OA in 2023 was 46.68 (95% UI: -0.47 to 124.21) per 100,000 population, reflecting a marked 58% increase (95% UI: 28% to 103%) from 1990. The highest age-specific rate of YLDs per 100,000 population were observed in the 70-74 years age group for combined OA [203.63 (95% UI: -2.02 to 549.41)], the 65-69 years age group for knee OA [191.51 (95% UI: -1.76 to 514.58)] and 80-84 years age group for hip OA [14.85 (95% UI: -0.17 to 42.17)]. Females had higher age-standardized YLD rates for both combined and knee OA. At the national level, the five countries with the highest age-standardized YLD rates attributable to high BMI for combined OA in 2023 were the Cook Islands, American Samoa, Niue, Tonga, and Nauru. Conclusion: The estimated number and rate of YLDs attributable to high BMI for OA showed a consistent upward trend over the study period in the Western Pacific Region. These findings highlight the substantial public health burden of OA associated with high BMI. Region-specific surveillance, prevention, policy, and management strategies targeting overweight/obesity are needed to reduce the OA burden in the Western Pacific Region.