Prevalence, functional impact, and associated factors of knee osteoarthritis and knee pain among adults in Urumqi, Northwest China: a community-based cross-sectional study.

BACKGROUND: Knee osteoarthritis and knee pain are major causes of chronic pain, functional limitation, and health-care use, but community-level evidence on their symptomatic burden and associated factors remains limited in northwest China. We aimed to estimate the burden of knee osteoarthritis and knee pain, describe pain-related functional impact, and examine demographic, clinical, lifestyle, and occupational factors associated with these outcomes among adults in Urumqi. METHODS: We conducted a community-based cross-sectional survey in Urumqi, Xinjiang, China, from June to August 2023. The primary analysis included adults aged 40 years or older with valid anthropometric and core knee outcome data. Outcomes were self-reported physician-diagnosed knee osteoarthritis, past-year knee pain, symptomatic knee osteoarthritis, and pain-related functional impact. Modified Poisson regression with robust variance was used to estimate adjusted prevalence ratios (aPRs) and 95% CIs. RESULTS: Among 1925 participants, the median age was 55.0 years (IQR 48.0-63.0), and 1,118 (58.1%) were men. Physician-diagnosed knee osteoarthritis was reported by 236 participants (12.3, 95% CI 10.9-13.8), past-year knee pain by 562 (29.2%, 27.2-31.3), and symptomatic knee osteoarthritis by 212 (11.0%, 9.7-12.5). Among participants with past-year knee pain, 214 of 525 reported sleep disturbance (40.8%, 36.6-45.0), 286 of 525 reported work or activity limitation (54.5%, 50.2-58.7), and 320 of 525 had sought medical care (61.0%, 56.7-65.0). Previous knee injury was strongly associated with physician-diagnosed knee osteoarthritis (aPR 3.08, 95% CI 2.37-4.00), past-year knee pain (2.01, 1.72-2.34), and symptomatic knee osteoarthritis (2.97, 2.25-3.91). Sleep disorder, overweight, obesity, high occupational mechanical load, and first-degree family history of arthritis were also associated with knee outcomes. CONCLUSION: Knee osteoarthritis and knee pain were common among middle-aged and older adults in Urumqi and were frequently accompanied by sleep disturbance, activity limitation, and health-care seeking. The observed associations with previous knee injury, excess body weight, occupational mechanical load, and sleep disorder identify groups that may warrant closer community assessment; their temporal and causal roles require confirmation in longitudinal studies.