Do device-measured physical activity and sedentary behavior differ by depression symptom status in persons with multiple sclerosis?

Depression is highly prevalent and impactful in persons with multiple sclerosis (MS). There are data indicating that the volume of physical activity behavior differs by depression symptom status in MS, yet less is known about the volume of sedentary behavior and its relationship with depression. We further know little about physical activity patterns and sedentary behavior and depression in MS.

This study examined differences in the volume (i.e., minutes/day) and pattern (i.e., bouts/day or bout length) of device-measured sedentary behavior and physical activity as a function of depression symptom status in persons with MS.

The sample of adults with MS (N=441) completed the Hospital Anxiety and Depression Scale (HADS) and wore a waist-mounted ActiGraph GT3X+ accelerometer during waking hours for 7 days. Participants were divided into subgroups of elevated (n=127) or non-elevated (n=314) depression symptoms based on a cut-point for the HADS scores (i.e., 8+ as indicative of elevated depressive symptoms). We examined the effect of depression group status differences on volume and pattern of sedentary behavior and light (LPA) and moderate-to-vigorous (MVPA) physical activity between subgroups using multivariate analyses of variance (MANOVA) and then multivariate analysis of covariance (MANCOVA) controlling for demographic/clinical variables that differed between the elevated and non-elevated depression groups.

Results of the MANOVA indicated an overall difference between subgroups in the volume, but not pattern, of physical activity and sedentary behavior. The non-elevated depression group had a significantly greater amount of steps/day (mean [M]=4584.3, standard deviation [SD]=2821.3), than the elevated depression group ([M]=3729.6, [SD]=2576.3, F=8.7; p=.003). Results of the MANCOVA revealed there was no statistically significant difference between the elevated and non-elevated depression groups in measures of volume of physical activity, and the difference in steps/day became non-significant F(1,438)= 2.13, p=.146), after controlling for disability, age, disease duration, and educations years.

This study observed no differences in sedentary behavior and physical activity as a function of depression symptom status in persons with MS, yet there was a difference in steps/day initially. Results demonstrated that when disability, age, disease duration, and years of education are included in the MANCOVA, the difference in depression groups is no longer significant. This suggests that steps/day could be an important target of health promotion interventions among persons with MS who have higher disability and elevated depression symptoms.