Predictors of exercise participation are different depending on ambulatory status among older people with multiple sclerosis

Background: Exercise at moderate intensity may confer neuroprotective benefits in multiple sclerosis (MS), however it has been reported that people with MS (PwMS) exercise less than national guideline recommendations. We aimed to determine predictors of moderate to vigorous exercise among a sample of older Canadians with MS who were divided into ambulatory (less disabled) and non-ambulatory (more disabled) groups. Methods: We analysed data collected as part of a national survey of health, lifestyle and aging with MS. Participants (n=743) were Canadians over 55 years of age with MS for 20 or more years. We identified ‘a priori’ variables (demographic, personal, socioeconomic, physical health, exercise history and health care support) that may predict exercise at moderate to vigorous intensity (>6.75 metabolic equivalent hours/week). Predictive variables were entered into stepwise logistic regression, adding and deleting correlated variables until best fit was achieved for each of the two groups (ambulatory and non-ambulatory). Results: Seventy-seven percent (77%) of participants in the ambulatory group (n=351) and 35% of the non-ambulatory group (n=392) were classified as exercisers. In the ambulatory group, exercise predictors included degree of disability (OR 1.95, 95%CI 1.18-3.25), depressive symptoms (OR 0.51, 95%CI 0.29-0.89) and perseverance (OR 1.8, 95%CI 1.04-3.10). In the non-ambulatory group, exercise predictors included degree of disability (OR 5.3, 95%CI 3.22-8.71) and perseverance (OR 2.1, 95%CI 1.27-3.54). It was also notable that the factors, age, gender, years with MS, co-morbid conditions, social support, health care support and financial status were not predictive of exercise. Conclusions: This is the first examination of exercise and exercise predictors among older, more disabled PwMS. Disability and perseverance are major predictors of exercise participation (at moderate to vigorous levels) in both ambulatory and non-ambulatory groups. Presence of depressive symptoms was only predictive in the ambulatory group. Our results suggest that more exercise options must be developed for people with greater disability. Perseverance and depression are both characteristics that are modifiable and are potential targets for exercise adherence interventions.