Risk factors of the symptomatic knee osteoarthritis in Koreans: A population-based cross-sectional study

Objective: The objective of this study was to evaluate the risk factors of symptomatic knee osteoarthritis (OA) in a Korean population. Design: A cross-sectional study. Materials and Methods: Total 368 adults aged 40 years and older in the general population living in the southwestern region of the Republic of Korea underwent a face-to-face interview to obtain demographic data and anthropometric measurements. Total body fat, visceral fat, and lower limbs muscle mass were measured using a body composition analyzer. And the Hospital for Special Surgery (HSS) protocol was used to evaluate symptomatic OA. Results: Age, female gender, low education level, working hours per day, waist circumference (WC), and body mass index (BMI) were identified as positive determinants of symptomatic knee OA, whereas lean body mass and lower limbs muscle mass were found to be inversely related. When BMI and WC were examined individually, they were found to positively predict symptomatic knee OA (BMI; odds ratio = 1.17, 95% CI; 1.05 - 1.31, WC; 1.05, 1.01 - 1.09). When subjects that were overweight (BMI > 25 Kg/m²) were subdivided by WC, the borderline (male; 90 - 102 cm, female; 80 - 90 cm) and inappropriate (male; ≥ 102 cm, female; ≥ 90 cm) WC subgroups were found to be more likely to have symptomatic knee OA than those with a normal WC subgroup. Conclusion: The prevalence of symptomatic knee OA was found to be high in the elderly and in overweight females, and to be strongly related to BMI and WC. Therefore, we recommend that interventions focused on weight reduction should be initiated in mid-aged women.