Research: Body Mass Index correlates poorly with mobility

Pilutti LA, Dlugonski D, Pula JH, Motl RW.Weight Status in Persons with Multiple Sclerosis: Implications for Mobility Outcomes. J Obes. 2012;2012:868256. Epub 2012 

The accumulation of excess body weight may have important health and disease consequences for persons with multiple sclerosis (MS). This study examined the effect of weight status on mobility using a comprehensive set of mobility outcomes including ambulatory performance (timed 25-foot walk, T25FW; 6-minute walk, 6MW; oxygen cost of walking, C(w); spatiotemporal parameters of gait; self-reported walking impairment, Multiple Sclerosis Walking Scale-12 (MSWS-12); and free-living activity, accelerometry) in 168 ambulatory persons with MS. Mean (SD) BMI was 27.7 (5.1) kg/m(2). Of the 168 participants, 31.0% were classified as normal weight (BMI = 18.5-24.9 kg/m(2)), 36.3% were classified as overweight (BMI = 25.0-29.9 kg/m(2)), and 32.7% were classified as obese, classes I and II (BMI = 30-39.9 kg/m(2)). There were no significant differences among BMI groups on T25FW and 6MW, C(w), spatiotemporal gait parameters, MSWS-12, or daily step and movement counts. The prevalence of overweight and obesity in this sample was almost 70%, but there was not a consistent nor significant impact of BMI on outcomes of mobility. The lack of an effect of weight status on mobility emphasizes the need to focus on and identify other factors which may be important targets of ambulatory performance in persons with MS.

This study looks at Body Mass Index and mobility and is a case of size doesn't matter