Physical Activity Intervention Improves Body Composition in Multiple Sclerosis: Preliminary Evidence from a Randomized Controlled Trial

Background: There has been increasing interest in body composition in persons with multiple sclerosis (MS) and there is evidence that those with MS have an unhealthy body composition. An unhealthy body composition profile can increase the risk of secondary disease consequences, such as bone fractures and comorbid health conditions. Physical inactivity is a modifiable risk factor for an unhealthy body composition profile. Consequently, increasing physical activity might favorably impact bone health and body composition in persons with MS.

Objectives: To examine the efficacy of a physical activity behavioral intervention for improving outcomes of body composition in persons with MS.

Methods: We conducted a 6-month randomized controlled trial (RCT) that examined the efficacy of an internet-delivered, physical activity behavioral intervention for improving outcomes of body composition, including whole body bone mineral content (BMC), bone mineral density (BMD), and soft tissue composition, in 82 ambulatory persons with MS. Participants were randomly assigned to the intervention (n=41) or waitlist control (n=41) condition using a computer-generated random numbers sequence.

Results: 35 intervention and 37 control participants completed the study. There was a significant effect of the intervention on whole body BMC (p=0.04, partial-η²=0.06) and BMD (p=0.01, partial-η²=0.09). The effect of the intervention on fat mass (p=0.05, partial-η²=0.06) and percent body fat (p=0.09, partial-η²=0.04) approached significance. There was not a significant effect on whole body lean soft tissue (p=0.28, partial-η²=0.02) or body mass index (BMI; p=0.86, partial-η²<0.001).

Conclusions: Our results provide preliminary evidence that an internet-delivered lifestyle physical activity intervention improves bone health, and to some extent body composition, in persons with MS. Such findings are important considering physical activity is a modifiable behavior and the potential long-term benefits for the prevention and management of fracture risk and comorbidities among those with MS.