Bone mineral density, pulmonary function, chronological age, and age at diagnosis in children and adolescents with cystic fibrosis.

OBJECTIVE To assess bone mineral density in patients with cystic fibrosis (CF), and to correlate it with possible intervening variables. METHODS Children and adolescents diagnosed with CF, aged 6 to 18 years, followed at the outpatient clinic were included in the study. First, demographic data were collected and, subsequently, patients underwent a spirometric test. All patients answered the Cystic Fibrosis Quality of Life Questionnaire (CFQ) and underwent the six-minute walk test (6MWT) and bone densitometry (DXA). RESULTS A total of 25 CF patients were included, of which 56% were males. The mean age was 12.3±3.4 years; mean height was 149.2±14.4 cm; and mean weight was 44.4±13.9 kg. Most results on pulmonary function and bone mineral density (BMD) were within normal limits. The mean forced expiratory volume in one second (FEV) was 92.5±23.6 (% of predicted), mean forced vital capacity (FVC) was 104.4±21.3 (% of predicted), and1 mean BMD z-score was 0.1±1.0. BMD was moderately correlated with FEV (r = 0.43, p = 0.03) and FVC (r = 0.57, p = 0.003). Regarding chronological age and age at diagnosis, a moderate and inverse correlation was also found (r = -0.55, p = 0.004; r = -0.57, p = 0.003, respectively). However, no significant correlations were found with the data from CFQ, 6MWT, and body mass index. CONCLUSION Most patients had BMD within normal limits and presented a positive correlation with pulmonary function, as well as a negative correlation with chronological age and age at diagnosis.