Bone metabolism markers in patients with systemic sclerosis

The mechanism of osteoporosis (OP) development in systemic sclerosis (SSc) remains unclear.Objective: to assess bone mineral density (BMD) and the level of bone metabolism markers (osteocalcin — OC, — C-terminal type I collagen telopeptides — b-CrossLaps) in the blood serum of patients with SSc.Patients and methods. 65 patients with SSc were examined, 6 (9%) men and 59 (91%) women, the average age was 51 [39; 61] year (main group), and 35 healthy individuals comparable in anthropometric parameters (control group). In all individuals were assessed the most important populational risk factors for OP. BMD was determined using dual energy X-ray absorptiometry (DXA); the level of vitamin D, OC and b-CrossLaps in blood serum — by enzyme immunoassay.Results and discussion. A decrease in BMD was statistically significantly more common in patients with SSc (46, 71%), than in controls (11, 31%). Significant risk factors for OP in SSc were early menopause, low physical activity, hypovitaminosis D, and probably high activity and duration of the disease. In patients with SSc, there was a significant decrease in the level of OC compared with the controls; in patients with a reduced BMD, the content of OC was significantly less than in patients with normal BMD. The average values of b-CrossLaps in the main and control groups were comparable, but in patients with OP this parameter was lower than in those with normal BMD.Conclusion. In patients with SSc, OP develops statistically significantly more often than in healthy individuals. Risk factors for OP are early menopause, low physical activity, long duration and high activity of SSc. The predominance of bone formation impairment over bone resorption as a mechanism for the development of secondary OP was noted.