Association of Body Mass Index With Disease Progression in Children With Charcot-Marie-Tooth Disease

Background and Objectives The aim of this study was to evaluate the impact of body mass index (BMI) on disease progression over 2 years in children with Charcot-Marie-Tooth disease (CMT). Methods BMI was classified in 242 participants aged 3–20 years with CMT enrolled in the Inherited Neuropathy Consortium, using the International Obesity Task Force (based on adult BMI values, kg/m2) criteria. Groups were categorized as severely underweight (BMI <17 kg/m2), underweight (BMI ≥17 to <18.5 kg/m2), healthy weight (BMI ≥18.5 to <25 kg/m2), overweight (BMI ≥25 to <30 kg/m2), and obese (BMI ≥30 kg/m2). Disease severity was assessed using the CMT Pediatric Scale (CMTPedS), a clinical outcome assessment of disability (0–44 points, mild to severe). Results At baseline, compared with individuals being of a healthy weight (mean CMTPedS 15.48, SD 9.22), children who were severely underweight (mean CMTPedS difference 9.03, 95% CI 0.94–17.12; p = 0.02), underweight (mean CMTPedS difference 5.97, 95% CI 0.62–11.31; p = 0.02), or obese (mean CMTPedS difference 7.96, 95% CI 1.03–14.88; p = 0.015) exhibited greater disability. At 2 years, compared with individuals being of a healthy weight (mean CMTPedS 17.53, SD 9.41), children who were severely underweight exhibited greater disability (mean CMTPedS difference 9.27, 95% CI 0.90–17.64; p = 0.02). Over the 2-year periods, the mean CMTPedS for the whole sample deteriorated by 1.72 points (95% CI 1.09–2.38; p < 0.001), with severely underweight children progressing at the fastest rate (mean CMTPedS change of 2.3, 95% CI 1.53–6.13; p = 0.21). In children who did not have a change in BMI categories over 2 years (69% of sample), CMTPedS scores deteriorated faster in those who were severely underweight (mean CMTPedS change 6.40 points, 95% CI 2.42–10.38; p = 0.01) than those of healthy weight (mean CMTPedS change 1.79 points, 95% CI 0.93–2.69; p < 0.001). For children who changed BMI categories (31% of sample), CMTPedS scores deteriorated faster in children who became overweight/obese (mean CMTPedS change 2.76 points, 95% CI 0.11–5.41; p = 0.031). Discussion Children with CMT who were severely underweight, underweight, or obese exhibited greater disability at baseline. Over the 2-year period in those whose BMI remained stable, severely underweight children deteriorated at the fastest rate. For children who changed BMI categories over the 2 years, CMTPedS scores deteriorated faster in children who became overweight/obese. Interventions that maintain or improve BMI toward healthy weight may reduce disability in children with CMT.