Physical activity, self-efficacy, and health-related quality of life in persons with multiple sclerosis: analysis of associations between individual-level changes over one year

Physical activity and self-efficacy represent behavioral and psychological factors, respectively, that are compromised in persons with multiple sclerosis (MS), but might be modifiable through intervention and result in better health-related quality of life (HRQOL). The present study adopted a panel research design and examined the associations between individual-level changes in physical activity, self-efficacy, and HRQOL over a one-year period in persons with MS. The sample consisted of 269 persons with relapsing-remitting MS who completed the Godin Leisure-Time Questionnaire (GLTEQ), Multiple Sclerosis Self-Efficacy (MSSE) Scale, and Multiple Sclerosis Quality of Life-29 (MSIS-29) Scale on two occasions that were separated by 1 year. The data were analyzed using panel analysis in Mplus 3.0. The initial panel analysis indicated that individual-level change in physical activity was associated with individual-level change in both physical and psychological HRQOL. The subsequent panel analysis indicated that (a) individual-level change in self-efficacy for functioning with MS was associated with individual-level change in physical HRQOL, whereas individual-level change in self-efficacy for control was associated with individual-level change in psychological HRQOL; (b) individual-level change in self-efficacy for functioning with MS, but not self-efficacy for control, mediated the association between individual-level change in physical activity and physical HRQOL; and (c) individual-level change in self-efficacy for controlling MS was the strongest predictor of individual-level change in HRQOL. Physical activity and self-efficacy both might be important targets of subsequent behavioral and self-management interventions for improving the HRQOL of persons with MS, although self-efficacy is seemingly more important than physical activity.