Adolescent development and energy expenditure in females with cystic fibrosis

Background & Aims Poor nutrition and growth status are common in people with cystic fibrosis (CF), and females often have a worse clinical course. Relationships between sexual maturity, nutrition, resting energy expenditure (REE), and pulmonary status in females with CF and pancreatic insufficiency (PI) were evaluated. Methods Pre- and post-menarcheal females with CF and PI (8–29 yr) were compared to healthy females. Z-scores for growth and body composition, anthropometry and DEXA were assessed. REE was measured in all subjects and pulmonary function in CF. Results Compared to healthy females (n=28, 14.6±4.1 yr), females with CF (n=16, 14.7±4.4 yr) had lower height Z (−0.1±0.9 versus −0.9±0.9, P=0.009) and muscle area Z (0.8±1.3 versus –0.4±1.2, P=0.007), and higher REE (100±10 versus 110±11% predicted, P=0.008). Difference in REE was more pronounced for post-menarcheal girls. REE adjusted for fat and fat-free mass was significantly higher with CF (+110 calories/day), and declined with menarcheal age in all subjects. FEV1 was positively associated with BMI Z score, and negatively associated with age at menarche. Conclusions Height and muscle stores were reduced and REE elevated in subjects with CF compared to healthy controls. Poorer growth and nutritional status and delayed menarche were associated with poorer pulmonary function in CF and were likely related to the cumulative effect of energy imbalance on growth and body composition.