BONE-MINERAL DENSITY AND BIOCHEMICAL MARKERS OF BONE METABOLISM IN ANKYLOSING-SPONDYLITIS

Objective. To determine (1) bone mineral density (BMD) of the axial an d appendicular skeleton in men with moderate and severe ankylosing spo ndylitis (AS), and (2) associations between BMD and bone metabolism va riables. Methods. Nineteen men with AS and 19 healthy male controls we re evaluated for osteoporosis by dual energy x-ray absorptiometry in b oth the hip and the lateral and posterior-anterior (PA) projections of the lumbar spine. Calcium homeostasis was evaluated by measuring mine rals, calcitropic hormones, and markers of remodeling. Total testoster one levels were also measured. Results. Osteopenia was noted in both t he hip and spine of the subjects with AS. The lateral projection of L3 was a more sensitive indicator of the vertebral BMD compared to the P A projection. Calcium homeostasis and testosterone levels were normal in subjects with AS. In most subjects, markers of bone formation and r esorption were normal. Conclusion. BMD of subjects with AS is decrease d, in spite of normal calcium homeostasis and bone remodeling indices.