Do physical activity and social cognitive theory variable scores differ across symptom cluster severity groups in multiple sclerosis?

BACKGROUND:Persons with multiple sclerosis (MS) experience co-occurring symptoms termed "symptom clusters" that can be distinguished based on mild, moderate, or severe symptom severity termed "symptom cluster severity." Physical activity (PA) may be an approach for improving co-occurring symptoms. OBJECTIVE:To examined if PA and social cognitive theory (SCT) variables differed by symptom cluster groups, and if associations between SCT variables and PA were moderated by symptom cluster groups. METHODS:Secondary analysis of participants with MS (N = 205) enrolled in a cross-sectional study. Trend analyses were conducted to determine if device-measured and self-reported PA and SCT variables (i.e., social support, self-efficacy, outcome expectations, goal setting, planning, and impediments) decreased with increased symptom cluster severity. Spearman rho rank-order correlations were conducted between PA measures and SCT variables within each symptom cluster group. RESULTS:Linear trend analyses indicated that self-reported PA declined with increased symptom cluster severity groups (F = 4.90,p = 0.03). Linear trend analyses indicated significant differences among symptom cluster severity groups in social support (F = 31.43,p = 0.001), exercise self-efficacy (F = 22.55,p = 0.001), barrier self-efficacy (F = 11.48,p = 0.001), outcome expectations (F = 6.98,p = 0.009), and impediments (F = 34.41,p = 0.001). There were differential associations of moderate magnitude in correlations, such that three SCT variables were associated with PA in the mild group (i.e., self-efficacy, goal setting and planning), two in the moderate group (i.e., social support and goal setting), and four in the severe group (i.e., self-efficacy, outcome expectations, planning, and social support). CONCLUSIONS:Further research is warranted examining the use of SCT-based behavior change techniques for promoting PA and improving symptom clusters in persons with MS.