J Pediatr Gastroenterol Nutr. 2025 May 19. doi: 10.1002/jpn3.70075. Online ahead of print.
ABSTRACT
OBJECTIVES: Children with inflammatory bowel disease (IBD) often have low body mass index (BMI). BMI does not distinguish between fat and lean mass. Body composition deficits may be associated with worse clinical outcomes. We examined the prevalence of risk factors associated with body composition deficits in youth with pediatric-onset IBD, and factors associated with low lean mass in the presence of a normal BMI Z-score (BMI-Z).
METHODS: Newly diagnosed IBD patients ages 5-20 years with whole body dual energy x-ray absorptiometry scans acquired between 2014 and 2019 were included. Appendicular lean soft tissue mass index (AppLSTMI) and fat mass index (FMI) were expressed as age and sex-specific Z-scores. Clinical and demographic data were collected retrospectively. Logistic regression was used to assess associations with body composition outcomes.
RESULTS: Five hundred sixteen patients were included, 26% had AppLSTMI Z-score (AppLSTMI-Z) < -2, 4% had BMI-Z < -2, and none had FMI Z-score (FMI-Z) < -2. Increased risk of low AppLSTMI-Z associated with Crohn’s diagnosis, Asian ethnicity, disease activity, elevated platelets, and glucocorticoid use. Females had lower FMI-Z. Low AppLSTMI-Z within the context of BMI-Z (n = 112) was associated with Crohn’s disease, Asian (odds ratio [OR] = 3.77, p = 0.001) and Black identity (OR = 0.32, p = 0.02), and elevated platelets (OR = 1.76, p = 0.02) compared to those with normal BMI-Z and normal AppLSTMI-Z.
CONCLUSIONS: BMI is a poor indicator of body composition in children with IBD as it masks lean mass deficits which are highly prevalent. Future studies regarding the long-term consequences and reversibility of this deficit are warranted.
PMID:40384504 | DOI:10.1002/jpn3.70075
