Bone and cartilage turnover markers, bone mineral density, and radiographic damage in men with ankylosing spondylitis.
OBJECTIVE
To determine the levels of bone and cartilage turnover markers in men with ankylosing spondylitis (AS) and to investigate their associations with disease activity, bone mineral density, and radiographic damage of the spine.


METHODS
This cross-sectional study enrolled 35 men with newly diagnosed AS. The bone mineral densities (BMD) of their lumbar spines and proximal femurs, Bath AS Disease Activity Index (BASDAI), and Bath AS Radiographic Index (BASRI) were evaluated. Urinary C-terminal telopeptide fragments of type I collagen (CTX-I) and type II collagen (CTX-II) levels were determined by enzyme-linked immunosorbent assay, and serum levels of bone-specific alkaline phosphatase (BALP) and osteocalcin were determined by an enzyme immunoassay. Levels of biochemical markers were compared with those of 70 age-matched healthy men.


RESULTS
Patients with AS had significantly higher mean urinary CTX-I and CTX-II levels than control subjects (p<0.05). Elevated urinary CTX-I levels correlated well with BASDAI, femoral BMD, and femoral T score (p<0.05), and elevated urinary CTX-II levels correlated well with spinal BASRI (p<0.05) in patients with AS. Mean serum BALP and osteocalcin levels did not differ between patients and controls and did not show any significant correlations with BMD, BASDAI, or BASRI in men with AS.


CONCLUSIONS
Elevated CTX-I reflects disease activity and loss of femoral BMD while elevated CTX-II levels correlate well with radiographic damage of the spine, suggesting the usefulness of these markers for monitoring disease activity, loss of BMD, and radiographic damage in men with AS.
Park
Min-Chan
MC
Division of Rheumatology, Department of Internal Medicine, Institute for Immunology and Immunologic Diseases, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Korea.
Chung
Soo-Jin
SJ
Park
Yong-Beom
YB
Lee
Soo-Kon
SK
D000293:Adolescent; D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000032:analysis* / Q000097:blood / Q000652:urine; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism* / Q000528:radiation effects; D002356:Cartilage / Q000378:metabolism / Q000528:radiation effects; D024042:Collagen Type I / Q000652:urine; D024043:Collagen Type II / Q000652:urine; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D015675:Osteocalcin / Q000097:blood; D013167:Spondylitis, Ankylosing / Q000378:metabolism*
D015415:Biomarkers; D024042:Collagen Type I; D024043:Collagen Type II; D015675:Osteocalcin; D000469:Alkaline Phosphatase