The relevant factors for knee pain in community-dwelling elderly: A cross-sectional study

Objective To clarify the comprehensive relevant factors for knee pain in elderly men and women independently living in the community.Methods A health and lifestyle survey was conducted using 1,133 independent living elderly participants from a district in local community. Demographics, health status, lifestyle, knee pain, and physical activity were measured. Knee pain was evaluated based on whether the individual had reported experiencing pain when he or she was walking at the ground level during the last two weeks. The International Physical Activity Questionnaire Short Version assessed physical activity and sitting time. With regards to physical activity, subjects were classified into two groups -"non-sufficiency" or "sufficiency"- based on the recommendation by the World Health Organization of 150 minutes per week. With regards to sitting time, subjects were classified into two groups -"long time" or "short time"- based on a median value of 5 hours of sitting time per week. The demographic variables evaluated were age, sex, education, and marital status. Health status was evaluated by measuring the individual's Body mass index (BMI) and by their current disease history. Lifestyle was evaluated based on the individual's dietary habits, alcohol consumption, and smoking status. Each variable was classified into two groups. Multiple logistic regression analysis was used to examine the association of knee pain with physical activity, sitting time, dietary habits, drinking, smoking, and BMI in men and women. All variables were entered simultaneously as independent variables. The models were adjusted for sex, age, education, marital status, and health status.Results The number of valid respondents for the analysis was 801 (response rate: 70.7%), including 365 men (74.9±6.9 years) and 436 women (74.9±6.9 years). Survey responses for men and women who had reported experiencing knee pain suggested that, only physical activity was significantly associated with knee pain in men (P=0.035). The odds ratio (OR) and 95% confidential interval (95% CI) for knee pain were 0.605 and 0.308-0.964, respectively. In women, BMI and dietary habits were significant relevant factors for knee pain (P=0.023 and P=0.004, respectively). The OR for BMI and dietary habits were 0.595 and 0.547, respectively while the 95% CI were (0.380-0.931) and (0.364-0.823), respectively.Conclusion The results of this study suggest that physical activity was a related factor for knee pain in men. In contrast, BMI and dietary habits were relevant factors for knee pain in women.