A longitudinal study of knee pain in older men: Concord Health and Ageing in Men Project.

BACKGROUND chronic knee pain is still considered a fairly benign disease by many, an 'unavoidable' consequence of ageing. This passive acceptance may be unnecessarily exposing older people to disability and serious co-morbidity. The aim of this study was to determine the disease burden associated with chronic knee pain and the role of knee extensor strength as a modifiable risk factor. METHODS a longitudinal cohort study with 2-year follow-up conducted among 1,587 community-dwelling men aged 70 years and over, 637 (40%) reported chronic knee pain. Of the 950 (60%) men without knee pain at baseline, 768 (81%) returned for the follow-up assessment with 150 (20%) reporting incident chronic knee pain. RESULTS knee pain was significantly associated with marked mobility disability [odds ratio (OR) 2.38; 95% confidence interval (CI) 1.74-3.29], falls (OR: 1.31; 95% CI: 1.01-1.70) and having four or more co-morbidity (OR: 1.63; 95% CI: 1.16-2.30) as well as reduced knee extensor strength and mass (dual X-ray absorptiometry). Men with incident knee pain at the 2-year follow-up assessment demonstrated greater increases in these measures of disease burden and greater decreases in muscle strength and mass, compared with those without incident chronic knee pain. Obesity, high co-morbidity burden, back pain, higher levels of physical activity or low knee extensor strength were all significant risk factors for incident knee pain. CONCLUSION prevention of chronic knee pain may reduce a considerable burden of mobility disability and increased risk of serious co-morbidity among older men.