Prevalence of low bone mineral density in adolescents and adults with cystic fibrosis

Roberta Vanacor, Fabiana V Raimundo, Natália A Marcondes, Bruno P Corte, Aline M Ascoli, Aline Z de Azambuja, Luciano Scopel, Patrícia V Dos Santos, Paulo T R Dalcin, Gustavo A M Faulhaber, Tânia W Furlanetto

Objective The aim of this cross-sectional study was to evaluate the prevalence of low bone mass density in cystic fibrosis patients as well as to evaluate the factors associated with bone mass in such patients. Methods Bone mass density was measured by dual-photon X-ray absorptiometry of lumbar spine (L1-L4), in patients ≤19 years old, or lumbar spine and femur (total and neck) in patients ≥20 years old. Evaluations of nutritional status, biochemical parameters, and lung function were performed. Medication data were obtained from medical records. Results Fifty-eight patients were included in the study (25 males/ 33 females), mean age 23.9 years (16-53years). The prevalence of bone mass below the expected range for age at any site was 20.7%. None of the subjects had history of fracture. Lumbar spine Z-score in cystic fibrosis patients correlated positively with body mass index (r= 0.3, p=0.001), and forced expiratory volume in the first second (% predicted) (r=0.415, p=0.022). Mean lumbar spine Z-score was higher in women (p=0.001), in patients with no pancreatic insufficiency (p=0.032), and in patients with no hospitalization in the last 3 months (p=0.02). After multivariate analysis, body mass index (p= 0.001) and sex (p=0.001) were independently associated with Z-score in lumbar spine. Conclusion Low bone mass is a frequent problem in patients with CF, being independently associated with body mass index, and male sex.