Association between knee pain and gait speed decline in rural Japanese community-dwelling older adults: 1-year prospective cohort study.

Aim: The present study examined whether knee pain was associated with decline in maximum gait speed (MGS) in a rural mountainous region.

Methods: This was a population-based 1-year prospective cohort study. A total of 658 men and women aged 60 years and older participated in the baseline survey in 2006, and 400 individuals participated in the follow-up survey in 2007. We compared the incidence of meaningful decline in gait speed (≥0.1 m/s) in older adults with different knee pain levels (none, mild, severe), estimating incidence rate ratio (IRR) by multivariable-adjusted Poisson regression model.

Results: Meaningful decline in MGS presented in 24.3% of participants, especially in men (30.3%). Baseline knee pain level was significantly related to meaningful decline in MGS after adjustment of potential confounders (IRR 1.79 for mild pain, 1.84 for severe pain; P for trend <0.01). In sensitivity analyses with change in MGS as the continuous variable, the association was not significant, but a similar negative association with knee pain was confirmed (mild pain β = -0.040, severe pain β = -0.088; P for trend = 0.104). In addition, older adults with knee pain at both baseline and follow up had a higher risk of meaningful decline in MGS (IRR 2.33, 95% CI 1.59-3.40) compared with those who had no pain at baseline or follow up.

Conclusions: Knee pain was associated with a decline in gait speed at 1-year follow up. Prevention and treatment of knee pain might be important for suppression of decline in physical function in older adults.