Epidemiology of osteoarthritis: 2026 update of the evidence

To update and extend a prior 2022 synthesis of osteoarthritis (OA) epidemiology with a focus on prevalence, incidence, and progression and risk factors of OA. This narrative review was conducted by identifying seminal studies and new peer-reviewed English-language publications since 2021, with a focus on person- and joint-level factors associated with OA. Recent global estimates show a continued rise in OA prevalence and incidence, driven by population aging, increasing obesity, and sex-specific patterns. Knee OA remains the most common joint site, followed by hand and hip OA, with notable variation across geographic regions, sociodemographic factors, and OA definitions. Person-level factors include age, sex, race/ethnicity, socioeconomic status, obesity, comorbidities, certain vitamins, smoking, occupation, and physical activity, with emerging evidence for ultra-processed food consumption, sleep disorders, and atopy. Beyond the mechanical loading of obesity, studies demonstrate a link between systemic metabolic and inflammatory pathways and OA across both weight-bearing and non-weight-bearing joints. Based on the literature, joint-level factors, including injury, surgical repair, anatomical abnormalities, malalignment, muscle strength and quality, and altered biomechanics, persist as important risk factors for OA onset and progression. The global impact of OA continues to increase. Evidence from this review suggests the critical need for intervention approaches at clinical and public health levels aimed at major risk factors, like obesity and joint injury, to mitigate the impacts of OA. Novel investigations of OA across the life course are necessary for OA prevention, early identification, and refinement of phenotypes for targeted interventions to reduce disease progression.