Whole body and regional bone mineral density in ankylosing spondylitis.
OBJECTIVE
To study the regional distribution of bone mass and look for factors leading to bone loss in ankylosing spondylitis (AS).


METHODS
Thirty-nine patients, all men, aged 20 to 55 years and presenting with AS were studied. Four hundred sixteen gendarmes, all men aged 20 to 55 years, formed an age matched control population used to define standard values for bone mineral density (BMD) in men. The patients with AS and the controls underwent measurement of whole body BMD and regional BMD by dual-energy x-ray absorptiometry.


RESULTS
AS was associated with spinal bone loss, with lumbar spine BMD (LSBMD) 1.085 +/- 0.178 g/cm2 in the AS group compared with 1.232 +/- 0.136 g/cm2 in the control group (p < 0.01). Whole body BMD and regional BMD of head, whole spine, pelvis, and legs were reduced, although this was not statistically significant. Using standard values for LSBMD from the controls, we found that 46% (18/39) of patients with AS had Z score < -1.5 SD. Biological markers of disease activity were higher in the subgroup of patients with low LSBMD than in the subgroup with normal LSBMD, with an erythrocyte sedimentation rate of 29.4 +/- 23.4 mm/h versus 12.1 +/- 10.8 mm/h (p < 0.05) and C-reactive protein at 24.8 +/- 18 mg/l versus 12.7 +/- 14.2 mg/l (p < 0.05).


CONCLUSIONS
AS is associated with bone loss, mainly concerning the lumbar spine, in patients whose disease is biologically most active.
Dos Santos
F P
FP
Department of Rheumatology, HGO Almada, Lisbon, Portugal.
Constantin
A
A
Laroche
M
M
Destombes
F
F
Bernard
J
J
Mazières
B
B
Cantagrel
A
A
D000328:Adult; D015415:Biomarkers; D001823:Body Composition; D001835:Body Weight; D015519:Bone Density; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013167:Spondylitis, Ankylosing / Q000473:pathology*
D015415:Biomarkers