title: Serum insulin-like growth factor binding protein-1 levels and bone mineral density in older adults: the Rancho Bernardo Study.
abstract: Insulin-like growth factor-I (IGF-I) stimulates osteoblast function, inhibits collagen matrix degradation, and is positively associated with bone mineral density in most but not all studies. We previously reported that IGF-I was positively associated with BMD at the spine and hip in women but not men. Insulin-like growth factor binding protein-1 (IGFBP-1), a potent modulator of IGF-I, is expressed in normal osteoblasts and inhibits collagen gene expression in bone, but little is known about the relationship between IGFBP-1 and bone mineral density (BMD). We report a cross-sectional study of serum IGFBP-1 levels and BMD in 1,139 community-dwelling men and postmenopausal women (not using estrogen), aged 44-98. In both sexes, IGFBP-1 levels increased linearly with age (p<0.001) and decreased with body mass index (BMI) quartile (p<0.001). After adjusting for age and BMI, there was no significant association between IGFBP-1 and BMD at the hip or spine. IGF-I and IGFBP-1 were weakly and inversely associated with each other. These findings suggest that if there is an important role for IGFBP-1 in bone metabolism, it is mediated or confounded by weight. Studies are needed to further investigate the relationship between inhibitory components of IGF-1 and bone loss.
authors.affiliation: Department of Medicine, University of California San Diego and VA San Diego Healthcare System, La Jolla, CA, USA. sjassal@ucsd.edu
authors.forename: Simerjot K
authors.initials: SK
authors.lastname: Jassal
authors.forename: Denise
authors.initials: D
authors.lastname: von Muhlen
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Barrett-Connor
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Rosen
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D049628:Body Size / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology; D005260:Female; D006615:Hip; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood; D011257:Pregnancy Proteins / Q000097:blood*; D012907:Smoking / Q000503:physiopathology; D049993:Sodium Chloride Symporter Inhibitors / Q000627:therapeutic use; D013256:Steroids / Q000627:therapeutic use
chemical_list: C032231:IGFBP1 protein, human; D018970:Insulin-Like Growth Factor Binding Protein 1; D018969:Insulin-Like Growth Factor Binding Proteins; D011257:Pregnancy Proteins; D049993:Sodium Chloride Symporter Inhibitors; D013256:Steroids; D007334:Insulin-Like Growth Factor I