Predictors Of Onset Of Knee Pain In Community-dwelling Elderly Women: A Prospective Study

Abstract

Knee pain is a common public health concern in older people. Predictors of its onset among community-dwelling elderly women have not been clear. PURPOSE: To investigate determinants of onset of knee pain in community-dwelling elderly Japanese women. METHODS: A prospective cohort study with 1-year follow-up was conducted among community-dwelling elderly women aged 50 and over in Kakeya, Unnan City, Shimane Prefecture, in rural Japan. 126 subjects without knee pain at baseline were prospectively followed over a 1-year period and assessed self-reported knee pain. Baseline surveys of potential predictors were physical (body mass index, low back pain), demographic (age, employed), psychological (depression) variables and physical activity (intensity of daily activity, daily means of transportation), and physical function (maximum walking speed, anteflexion). Predictors related to onset of knee pain were assessed by calculating odds ratios (OR) and their 95% confidence intervals (CI) adjusted for all measures at baseline using logistic regression. RESULTS: The incidence of knee pain at the 1-year follow-up was 19.0%(24/126) among subjects with no knee pain at baseline. Baseline factors significantly associated with onset of new knee pain were overweight(BMI≥25, OR 5.08, 95% CI 1.33-19.40, depression (OR 4.10, 95% CI 1.28-13.19), vigorous daily activity (OR 5.62, 95% CI 1.20-26.41) and low back pain (OR 2.96, 95% CI 1.02-8.60). Using inactive transportation (bus, train, car and motorbike) showed a somewhat increase but statistically insignificant OR (2.93, 95% CI 0.93-9.26, p=0.067) as compared with active transportation (walking and bicycle). CONCLUSIONS: Overweight, depression, vigorous daily activity, and low back pain were associated with onset of knee pain among rural Japanese elderly women.