Body mass index underestimates adiposity in women with spinal cord injury

OBJECTIVE: To assess the relationship between body mass index (BMI) and adiposity as well as the influence of injury level on this relationship in 24 women with spinal cord injury (SCI) and 23 able-bodied (AB) women with similar age, race, and BMI. DESIGN AND METHODS: Body composition was measured by dual energy x-ray absorptiometry (DXA). Analysis of covariance was performed to compare total and regional soft tissue percent fat (PF) measures between groups. RESULTS: Women with SCI had a higher soft tissue PF than AB women at any given BMI. The BMI-adjusted soft tissue PF (mean ± SE) was 44.4 ± 1.8%, 37.8 ± 1.3%, and 35.9 ±1.1% for tetraplegic, paraplegic, and AB women, respectively. The BMI explained about equal amounts of the variance in soft tissue PF among paraplegic and AB women (65%), but only 28% in tetraplegic women. CONCLUSION: This study confirms a limited use of BMI in measuring adiposity in women with SCI, particularly among those with tetraplegia. Our observation of lower BMI cutoff points for defining obesity (28 kg/m(2) for paraplegia and 21 kg/m(2) for tetraplegia) needs further confirmation. The underweight/malnutrition issue also deserves the consideration while proposing the ideal weight and BMI range for persons with SCI.