The prevalence of aberrations in body composition in pediatric cystic fibrosis patients and relationships with pulmonary function, bone mineral density, and hospitalizations.

BACKGROUND

Body mass index (BMI) correlates with clinical outcomes in cystic fibrosis but has limitations.  Body composition aberrations in CF are multifactorial. We sought to evaluate body composition and relationships with pulmonary function, bone health, and hospital admissions. Other aims included defining body composition indices in a cohort of children with CF.

METHODS

We conducted a retrospective review of patients with CF, age 8-18 years, seen at Nationwide Children's Hospital (2015-2020). Indices of body composition measured by dual-energy x-ray absorptiometry(DXA) scans.  Data included fat mass, fat-free mass (FFM), forced expiratory volume in one second (FEV1%), bone mineral density (BMD), and hospital admissions. NWA was defined as BMI 5-85 percentile, body fat percentage >85 percentile. FFMD defined as FFMI <10 percentile.

STATISTICS

T-tests compared NWA, FFMD and clinical measurements. Pearson correlations analyzed fat-free mass index (FFMI), fat mass index (FMI), BMI and clinical measurements.

RESULTS

This study included 114 patients.  Mean age 12 years, 72 female. A high prevalence of FFMD existed (n=66, 38.6%).  FMI and FFMI correlated with FEV1% (r: 0.23, p:0.01, r: 0.36, p<0.001, respectively) and BMD (r: 0.29, p:0.002). FMI and hospital admissions were related (r:-0.23,p:0.01). FFMD was associated with 9.5% lower FEV1% (p=0.001) and lower BMD Z-score by 1.1 (p<0.001) when compared to no FFMD.

CONCLUSION

This cohort of children with CF had a high prevalence of FFMD and low prevalence of NWA.  FFMD was associated with worsened clinical measurements. Patients with FFMD need additional exercise or nutritional intervention. Heterogeneity of body composition definitions creates need for more research.