Background: Several cross-sectional studies have shown improvement in the growth of children with cystic fibrosis (CF) because of increased awareness of and more comprehensive care of their special nutritional needs. However, longitudinal data on the nutritional status of these children are rare.
Objective: The objective was to compare changes in growth, body composition, and nutritional status between children with and without CF.
Design: This was a prospective 3-y cohort study of 25 children aged 5-10 y with CF, mild pulmonary disease, and pancreatic insufficiency and of 26 healthy control children. Three methods were used to assess body composition: measurements of skinfold thickness, total body water by deuterium oxide, and total-body electrical conductivity. Growth and body-composition changes over time were analyzed by a longitudinal mixed-effects model.
Results: Over the 3 y of the study, the statural growth of the boys with CF was slower than that of the control subjects (P = 0.004). The same divergence over time between the boys with and without CF was observed for fat-free mass assessed by skinfold-thickness measurements and total body water (P = 0.008 and 0.02, respectively) and for fat mass assessed by skinfold-thickness measurements and total-body electrical conductivity (P = 0.009 and 0.001, respectively). The differences in the pattern of changes in growth and body composition were less striking for girls.
Conclusions: Despite comprehensive care, the growth of boys with CF was impaired on the basis of height, fat-free mass, and fat mass, when observed longitudinally. Caution should be used when interpreting cross-sectional measurements because they often do not detect suboptimal growth.