Objective: Research emphasizes the negative impact of osteoarthritis (OA) on social participation, yet few studies have examined the roles of symptoms, activity limitations, and depression in this relationship. The present longitudinal study tested a model that hypothesizes that the relationship between physical symptoms and later participation restrictions among older adults with OA is mediated by activity limitations and depressive symptoms.
Methods: Participants were 184 community-dwelling senior adults (age>or=55 years) with a physician diagnosis of OA who were interviewed at 2 time points 18 months apart. Measures included demographic variables; a derived physical symptoms measure based on severity of pain, stiffness, and fatigue in the previous week; and depressive symptoms measured by the Center for Epidemiologic Studies Depression Scale. Measures of activity limitations and participation restrictions were derived by factor analysis of questions about difficulty in everyday life. Sequential multiple linear regression analyses controlling for demographic and illness-related variables were used to test for mediation.
Results: Severity of time 1 physical symptoms was associated with difficulties in participation 18 months later. Sequential introduction of variables showed that this relationship was partially mediated by time 1 activity limitations and time 1 depressive symptoms. When both of these variables were included in the model, the effect of symptoms severity was completely mediated.
Conclusion: This study demonstrates the importance of taking into account both the physical (activity limitations) and psychological (depressive symptoms) consequences of OA symptoms and suggests that these factors act as a pathway to subsequent participation restrictions.