Body mass index and waist circumference in persons aging with muscular dystrophy, multiple sclerosis, post-polio syndrome, and spinal cord injury.

BACKGROUND: Body mass index (BMI) and waist circumference (WC) are well-understood in the general population, but are not adequately understood among persons with disabilities. OBJECTIVE: To describe and compare BMI and WC among individuals with muscular dystrophy (MD), multiple sclerosis (MS), post-polio syndrome (PPS), and spinal cord injury (SCI). BMI scores were also compared to normative data of the U.S. population, with consideration for age, sex, and mobility limitations. METHODS: Persons with MD (n = 339), MS (n = 597), PPS (n = 443), and SCI (n = 488) completed postal surveys that included self-reported BMI and WC data. NHANES data were used to compare the current sample with a representative US sample. RESULTS: Participants with PPS had higher BMI than participants with MD, MS, and SCI. In addition, participants with MS had significantly higher BMI relative to participants with SCI. BMI was significantly positively associated with age, years since diagnosis, mobility, and interactions of some of these factors. Relative to the general population, BMI was lower in MD, MS, and SCI across age groups, as well as in men with PPS and women ages 60-74 years with PPS. No significant differences were identified between MD, MS, PPS, and SCI in WC. CONCLUSIONS: The presence of group differences in BMI and absence of group differences in WC suggests that BMI may not accurately represent health risk in SCI, MD, and possibly MS, because of biasing elements of the conditions, such as changes in body composition and mobility limitations.