Physical activity in non-disabled people with early multiple sclerosis: A multicenter cross-sectional study

Background: People with Multiple Sclerosis (PwMS) show low levels of physical activity (PA), however there has been limited research on PA in early diagnosed and no/minimally impaired (<5 years, EDSS <= 2.5) PwMS. The aims of the study were to objectively quantify PA levels in non-disabled PwMS, to compare the time spent daily at different PA levels (No activity (NPA), Light PA (LPA), Moderate PA (MPA), and Vigorous PA (VPA)) with healthy subjects (HS), and to examine the association of PA with disability, and clinical measures in PwMS. Methods: We assessed 58 PwMS (mean age +/- standard deviation, SD 39.1 +/- 10.6years) and 20 HS (mean age +/- SD 39.3 +/- 8.9 years). Demographic and clinical data were recorded at the hospital during the baseline assessment. Subjects wore the wrist GENEActiv accelerometer for 7-days. Data were collected at 100 Hz and summarized into a motor activity (MA) index using 60 s epochs with the following thresholds: MANPA-LPA: 10mG, MALPA-MPA: 100mG, MAMPA-VPA: 350mG. Results: PwMS show higher NPA and lower VPA compared to matched healthy subjects (NPA: Mean +/- SD, HS: 7.2 +/- 0.9 h/day; PwMS: 8.1 +/- 1.2 h/day, p<0.01; VPA: HS: 0.78 +/- 0.42 h/day; PwMS: 0.50 +/- 0.40 h/day, p = 0.01), while no between group differences were observed for LPA and MPA (p>0.05). Bivariate analysis showed that higher NPA was associated with fatigue (Fatigue Severity Scale, FSS score) in PwMS with EDSS 0-1.5 (r = 0.34, p = 0.05). In PwMS with EDSS 2-2.5, NPA was correlated with Six Minute Walk Test (6MWT, r=-0.45, p = 0.02) and CIQ (r=-0.41, p = 0.04), while VPA was more associated with FSS (R= -0.38, p = 0.06). Conclusion: The PA level of PwMS differs from that of healthy subjects even in early diagnosed subjects. In PwMS with EDSS 0-1.5 only, fatigue is associated to prolonged inactive behavior. Conversely, in PwMS with EDSS 2-2.5 both inactivity and vigorous activities are modulated by fatigue, endurance and associated with different level of social participation.