Physical Activity and Life Stress Are Associated With Illness Intrusiveness in Persons With Multiple Sclerosis.

ABSTRACT

OBJECTIVES: To explore which modifiable lifestyle behaviors contribute to illness intrusiveness in persons with multiple sclerosis (MS). DESIGN: Cohort study. SETTING: Community-based comprehensive MS center. PARTICIPANTS: Adults with MS (N=154) who completed an online battery of self-report questionnaires. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Illness intrusiveness was measured with the 13-item Illness Intrusiveness Ratings Scale. Lifestyle behaviors were measured using the respective components of the Simple Lifestyle Indicator Questionnaire (ie, Diet, Physical Activity, Alcohol, Smoking, and Life Stress) and self-reported body mass index (BMI). RESULTS: After controlling for age, race, sex, disease duration, and level of physical disability ("disability"), life stress was associated with greater illness intrusiveness (b=4.65, P<.001), and physical activity was associated with less illness intrusiveness (b=-0.67, P=.009). Exploratory mediation analyses revealed physical activity had an indirect effect on illness intrusiveness through disability (b=-0.39, 95% CI -0.68, -0.16). Conversely, disability also displayed an indirect effect on illness intrusiveness through physical activity (b=0.57, 95% CI 0.12, 1.16). CONCLUSIONS: Life stress and physical activity are 2 modifiable lifestyle behaviors that contribute to illness intrusiveness, with the latter also having an indirect effect through disability. These findings may help inform future behavioral interventions for improving health-related quality of life in persons with MS.