Objective: To examine the associations between obesity, defined using the spinal cord injury (SCI)-specific (>22 kg/m2) and the standard (≥30 kg/m2) body mass index (BMI) thresholds, and determine which index better discriminates against BMI-related cardiometabolic, physical, and psychosocial associations reported among the general population in chronic traumatic SCI (TSCI).
Design: Multicenter cross-sectional study.
Setting: Sixteen SCI Model System (SCIMS) sites.
Participants: Adults with TSCI (n=1523, 78.7% men, age 45.7±15.9y, 56.7% tetraplegia, 8.5±10.5y post-SCI). Participants were stratified into groups based on BMI >22 (n=1123) and BMI ≥30 kg/m2 (n=376), using available height and weight, follow-up data, and complete outcomes data from the 2016-2020 SCIMS database.
Interventions: Not applicable.
Main outcome measures: Prevalence and odds of self-reported cardiometabolic (diabetes, hypertension, and hyperlipidemia), physical (arthritis, pressure injuries [PI], urinary tract infections [UTI], falls, and rehospitalizations), and psychosocial (Patient Health Questionnaire-9, Resilience Short Form, Satisfaction with Life Scale, and Self-perceived Health [SPH]) measures.
Results: Obesity prevalence was 73.7% using the SCI-specific threshold and 24.7% using the standard threshold. Individuals classified as obese by either definition had higher odds of diabetes, hypertension, and hyperlipidemia, with consistent findings across all neurologic impairment categories. Arthritis was more prevalent among individuals with than without obesity, but increased odds were observed only for those with a BMI ≥30 kg/m2. UTIs and PI were more common among participants with a BMI >22 kg/m2, whereas poorer SPH was associated with a BMI ≥30 kg/m2. No significant associations with psychosocial outcomes were found using either threshold.
Conclusions: The SCI-specific BMI classified more persons as obese than the standard threshold, yet both thresholds were associated with cardiometabolic risk. Patterns diverged for other outcomes (arthritis, SPH at ≥30), suggesting common obesity-health risk patterns may not generalize to SCI. These findings highlight the complexity of obesity in SCI, underscoring that despite BMI's common use, more accurate, clinically accessible measures are needed to improve risk identification.

