Prevalence and factors associated with knee osteoarthritis among middle-aged and elderly individuals in rural Tianjin: a population-based cross-sectional study

BACKGROUND: The prevalence of osteoarthritis has been investigated in many countries and regions. Considering the wide differences in ethnicity, socioeconomic status, environmental factors, and lifestyle patterns, our study aimed to report the prevalence of knee osteoarthritis (KOA) and its associated factors in rural areas of Tianjin. METHODS: This population-based cross-sectional study was conducted between June and August 2020. KOA was diagnosed according to the 1995 American College of Rheumatology criteria. Information on participants’ age, years of education, BMI, smoking and drinking status, sleep quality, and frequency of walking were collected. Multivariate logistic regression analysis was used to analyze factors influencing KOA. RESULTS: This study included 3924 participants (1950 male and 1974 female); the mean age of all participants was 58.53 years. In total, 404 patients were diagnosed with KOA, and the overall prevalence of KOA was 10.3%. The prevalence of KOA was higher in women than in men (14.1% vs. 6.5%). The risk of KOA in women was 1.764 times higher than that in men. The risk of KOA increased following the increasement of age. There was higher risk of KOA in participants who walked frequently than in participants who walked infrequently (OR = 1.572); in participants with overweight than in participants with normal weight (OR = 1.509), in participants with average sleep quality (OR = 1.677) and those with perceived poor sleep quality (OR = 1.978), respectively, than participants with satisfactory sleep quality, and in postmenopausal women than in non-menopausal women (OR = 4.12). The risk of KOA in participants with an elementary level was lower (0.619 times) than participants with illiteracy. In addition, the results of gender subgroup analysis showed that in male, age, obesity, frequent walking and sleep quality were independent factors associated with KOA; while in female, age, BMI, education level, sleep quality, frequent walking and whether menopausal were independent factors associated with KOA (P < 0.05). CONCLUSION: The results of our population-based cross-sectional study showed that sex, age, educational level, BMI, sleep quality, and frequent walking were independent influencing factors for KOA, and the influencing factors for KOA differed between the sexes. In order to reduce the disease burden of KOA and the harm to the health of middle-aged and elderly people, the risk factors related to the control of KOA should be identified as much as possible. Trial registration: ChiCTR2100050140.