[Bone mineral density and bone metabolism in spondylarthropathies]

To study the prevalence of osteoporosis in a group of patients with spondyloarthropathy and to investigate bone turnover markers and correlation between bone mineral density and the age at the beginning of the disease.

Patients with spondyloarthropathy as defined by New York and ESSG criteria. Bone mineral density was measured at the lumbar spine and hip with Hologic QDR 1000. Serum levels of osteocalcin, deoxypyridinoline, 25 vitamin D, creatinine and parathyroid hormone were measured.

50 patients were included in the study: 37 men, mean age 40,2+/-13,8 years. Vertebral osteopenia was observed in 34% while femoral osteopenia occurred in 40% of patients. Serum vitamin D was low in 70% of patients without parathyroid hormone or kidney function modification. Markers of bone turn over were increased in 29% of patients. There was no correlation between these biological markers and the bone mineral density. We observed a significative correlation (P=0,02) between the age at the beginning of the disease and the bone mineral density.

Osteopenia is present in patients with spondyloarthropathy without any correlation with the bone turnover biological markers. We observed a significative correlation between the age at the beginning of the disease and bone mineral density.