Association of foot symptoms with self-reported and performance-based measures of physical function: The Johnston County osteoarthritis project.

OBJECTIVE: To examine associations of foot symptoms with self-reported and performance-based measures of physical function in a large, biracial, community-based sample of individuals ages ≥45 years.
METHODS: Data from 2,589 Johnston County participants (evaluated in 1999-2004) were used in cross-sectional analyses. The presence of foot symptoms was defined as pain, aching, or stiffness of at least one foot on most days. Physical function was assessed by the total Stanford Health Assessment Questionnaire (HAQ) score (0, >0 but <1, and ≥1), timed 5 repeated chair stands (completion time <12 seconds, ≥12 seconds, and unable), and 8-foot walk time (<3.35 seconds and ≥3.35 seconds). Separate multivariable logistic regression models examined associations between foot symptoms and physical function measures, controlling for age, race, sex, body mass index, radiographic knee osteoarthritis, radiographic hip osteoarthritis, knee symptoms, hip symptoms, and depressive symptoms. Interaction terms between each of the 3 physical function measures and each demographic and clinical characteristic were examined.
RESULTS: The prevalence of foot symptoms was 37%. Participants with foot symptoms were more likely than those without symptoms to have higher HAQ scores (adjusted odds ratio [OR] 1.79, 95% confidence interval [95% CI] 1.50-2.12). Among obese participants, those with foot symptoms had longer chair stand (adjusted OR 1.38, 95% CI 1.04-1.87) and 8-foot walk times (adjusted OR 1.61, 95% CI 1.21-2.15) than those without symptoms.
CONCLUSION: Foot symptoms were independently and significantly associated with 2 of 3 measures of poorer physical function. Interventions for foot symptoms may be important for helping patients prevent or deal with an existing decline in physical function.