Abdolhamid Jafari Nodoushan - Assistant professor, Department of Pediatrics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Soheila Khalilzadeh - Pediatric Respiratory Disease Research Center, NRITLD, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Azam Golzar - Researcher of Children Growth Disorder Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Maryam Hassanzad - Associate Professor, Pediatric Respiratory Disease Research Center,NRITLD,Masih Daneshvari Hospital,shahid Beheshti University of Medical Sciences,Tehran,Iran.

Background: Failure to maintain bone mass density is a major complication in patients with cystic fibrosis (CF). This study was conducted to evaluate the prevalence of low bone mineral density (BMD) and also identifying associated risk factors in CF patients. Materials and Methods: Present study conducted on 59 CF patients aged 5-35 years referred to respiratory clinic of Masih Daneshvari Hospital, Tehran-Iran. BMD was measured using dual energy X-ray absorptiometry (DXA) scan. Patients were divided in two groups: cases aged 5-18 years as group A and cases over 18 years as group B. Anthropometric variables, corticosteroid usage, pulmonary function test, serum calcium, phosphate and 25-OH vitamin D were assessed and correlation of them with BMD was investigated.Results: Low BMD (Z score < -2 standard deviation) was found in 72.8% (44) of patients. There was a positive correlation between malnutrition, Forced Expiratory Volume 1 (FEV1) and BMD (r=59 and 0.47, P<0.01, respectively). Steroid therapy and Pseudomonas aeruginosa colonization correlated significantly inversely with BMD (r = -0.34 and -0.32, P<0.05). Vitamin D deficiency was found in 36.7% (18) CF patients. No significant correlation was found between 25-OH vitamin D levels and BMD (r = 0.17; P=0. 23).Conclusion: In present study, the prevalence of low BMD was about 72.8% with significant correlation with low weight, BMI (poor nutritional status), FEV1,Pseudomonas aeruginosacolonization and the use of glucocorticoids.

Bone mineral density, Children, Cystic fibrosis, Dual-energy X-ray absorptiometry