[Bone mineral density in patients with cystic fibrosis by dual-energy X-ray absorptiometry].

Background: The aim of this study was to assess the bone mineral density of cystic fibrosis patients.

Patients And Methods: We have retrospectively studied 45 patients with cystic fibrosis, 22 females and 23 males, aged between six and 27 years (mean 13 +/- 5.5 years). Nutritional status, Shwachman score, pulmonary function, serum calcium and 25-hydroxyvitamin D levels and lumbar bone mineral density by dual energy X-ray absorptiometry were assessed.

Results: The average height of the patients was 97 +/- 4% (range: 86-106) and body mass index 93 +/- 10% (range 77-114) of the normal values of age. The average Shwachman score was 80 +/- 11/100 (range: 47-96). The forced expiratory volume in 1s was 80 +/- 29% (21-128) and the vital capacity 85 +/- 21% (range: 40-122) of the predicted values. The serum levels of calcium and 25-hydroxyvitamin D were lower than normal values in six cases and one case respectively. Thirty-eight patients had a mean lumbar spine bone mineral Z-score which was -1.35 +/- 1.2 DS and 84.7 +/- 13.5% of the normal values. It was correlated with the height, the body mass index, the Shwachman score, the FEV 1 and the vital capacity.

Conclusion: Decreased bone density is frequent among cystic fibrosis subjects. It shows a lack of control of the illness. It remains unknown with usual investigation; the dual X-ray absorptiometry should, each time it is possible, take part of investigations in those patients.