Impaired physical fitness in pediatric inflammatory bowel disease.

Objective: There are only a few studies on physical fitness in pediatric inflammatory bowel disease (PIBD). We compared physical fitness in PIBD patients versus healthy controls and analyzed the role of contributing disease- and patient-related factors.

Methods: This cross-sectional study included 73 patients with PIBD aged 13.0 (2.8) (mean [standard deviation]) years from two Finnish university hospitals, 31 with Crohn's disease and 42 with ulcerative or unclassified colitis, and 74 age- and sex-matched controls. Cardiorespiratory and neuromuscular fitness were assessed, physical activity (PA) was measured, and disease characteristics concerning physical fitness were analyzed.

Results: Cardiorespiratory fitness, that is, maximal workload (W_max/kg) and peak oxygen uptake (VO₂peak/kg) were lower in patients with PIBD than in controls: W_max/kg 3.01 (0.72) versus 3.29 (0.57) W/kg, p = 0.007; VO₂peak/kg 38.3 (8.5) versus 46.9 (7.4) mL/kg/min, p < 0.001, respectively. Neuromuscular fitness, as evaluated using sit-up, standing long jump, grip strength, and shuttle run tests, was lower in patients compared with controls. Disease activity, severity, and duration, or PA, were not related to W_max/kg and VO₂peak/kg in univariate analysis. However, in multivariate analysis, the use of biological medications was associated positively, and higher age- and sex-adjusted body mass index for children and adolescents was associated negatively with W_max/kg and VO₂peak/kg.

Discussion: Patients with PIBD had lower physical fitness than age- and sex-matched controls. The causes of lower physical fitness in PIBD are likely complex, warranting the need for longitudinal studies examining the associations of factors like body composition, visceral fat, and control of disease severity with physical fitness.