[Assessment of selected bone metabolism marker concentrations in children with cystic fibrosis].

AIM

The aim of this study was to assess bone formation and resorption processes and bone metabolism regulators, such as osteoprotegerin and fetuin-A in children with cystic fibrosis.

MATERIAL AND METHODS

We examined 45 children with cystic fibrosis aged 5-13 years treated at the Institute of Mother and Child in Warsaw. The control group consisted of 35 healthy children in the same synage range without any diseases which may influence bone metabolism. We determined serum calcium and phosphate levels by colorimetric methods, vitamin D3 by the chemiluminiscence method and bone metabolism markers (osteocalcin, 5b isoenzyme of tartrate-resistant acid phosphatase, osteoprotegerin, fetuin-A) by immunoenzymatic methods.

RESULTS

Mean serum concentrations of calcium and phosphate in the studied children were within the reference ranges. However, the level of 25-hydroxyvitamin D3 was significantly lower in patients with cystic fibrosis compared to the controls (19.3±7.6 vs 25.2±8.9 ng/ml, p<0.01). In cystic fibrosis children we observed a statistically significant lower concentration of osteocalcin (81.9±28.9 vs 97.9±28.6 ng/ ml, p<0.01) and similar activity of 5b isoenzyme of tartrate-resistant acid phosphatase (12.5±2.9 vs 13.4±3.5 U/L) as compared to healthy peers. Mean serum concentration of osteoprotegerin in patients with CF was significantly lower than in the control children (4.1±0.98 vs 4.59±0.86 pmol/l, p<0.05). Serum concentration of fetuin-A was comparable in both groups of children.

CONCLUSIONS

In children with cystic fibrosis changes in the profile of bone metabolism markers were observed. Even patients with CF who are clinically stable and supplemented with vitamins are at risk of osteopenia and osteoporosis in their later life. Therefore, they should be under a comprehensive medical and nutritional care in order to achieve their optimal peak bone mass.