Serum levels of insulin-like growth factor (IGF) I, IGF-binding protein (IGFBP)-2, and IGFBP-3 in osteoporotic patients with and without spinal fractures.
The present study was performed to investigate the role of insulin-like growth factor I (IGF-I), IGF-binding protein-2 (IGFBP-2), and IGFBP-3 in age-dependent bone loss in postmenopausal Japanese women. One hundred and sixty-five Japanese women aged 43-88 years (mean age, 62) were enrolled in the cross-sectional study. Bone mineral density (BMD) was measured at the lumbar spine, femoral neck, and midradius by dual-energy X-ray absorptiometry or single-photon absorptiometry. Serum levels of IGF-I, IGFBP-2, and IGFBP-3 were measured by radioimmunoassay. BMD at all sites as well as serum levels of IGF-I and IGFBP-3 declined with age, while the serum IGFBP-2 level increased with age. Serum IGFBP-3 and -2 levels were positively and negatively correlated with the serum IGF-I level, respectively. Serum IGF-I and IGFBP-3 levels showed positive correlationship with BMD at any site, particularly at the midradius, while the serum IGFBP-2 level showed negative correlation with BMD. Multiple regression analyses showed age-independent positive correlation between the serum IGF-I level and BMD at all sites as well as age-independent positive correlation between the serum IGFBP-3 level and midradius BMD. The relationship between susceptibility to osteoporotic spinal fracture and serum IGF-I, IGFBP-3, or -2 levels was examined by decade to exclude the influence of aging. Serum levels of IGF-I and IGFBP-3 were significantly lower in subjects with spinal fractures than those without fractures at any decade. No significant difference of serum IGFBP-2 level was observed between subjects with and without fractures. The present findings suggest that IGF-I and IGFBP-3 are important to maintaining bone mass quantitatively as well as qualitatively, and that the determination of serum IGF-I and IGFBP-3 levels could be clinically useful to predict the severity of osteoporosis, particularly the risk of bone fracture associated with osteoporosis.
Sugimoto
T
T
Department of Medicine, Kobe University School of Medicine, Japan.
Nishiyama
K
K
Kuribayashi
F
F
Chihara
K
K
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007564:Japan; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries / Q000502:physiology; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood* / Q000503:physiopathology; D012044:Regression Analysis; D016103:Spinal Fractures / Q000097:blood* / Q000209:etiology; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries / Q000502:physiology
D001798:Blood Proteins; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I