title: Association between insulin-like growth factor I and bone mineral density in older women and men: the Framingham Heart Study.
abstract: Few studies of the GH axis and bone have focused specifically on elderly people. The objective of this study was to determine the association between insulin-like growth factor I (IGF-I) and bone mineral density (BMD) in 425 women and 257 men aged 72-94 who participated in the Framingham Osteoporosis Study component of the Framingham Heart Study in 1992-1993. Serum IGF-I level was determined by RIA. BMD at three femoral sites and the lumbar spine was determined by dual x-ray absorptiometry, and at the radius by single-photon absorptiometry. IGF-I level was positively associated with BMD at all five sites (Ward's area, femoral neck, trochanter, radius, and lumbar spine) in women after adjustment for weight loss and other factors (P < or = 0.01) and protein intake in a subset of participants (0.006 < P < 0.07). A threshold effect of higher BMD was evident at each of the 3 femoral sites and the spine (P < 0.03) but not at the radius for women in the highest quintile of IGF-I (> or = 179 g/liter) vs. those in the lowest four quintiles. IGF-I was not significantly associated with BMD in men. These results indicate that higher IGF-I levels are associated with greater BMD in very old women, and suggest that future clinical trials employing GH may have a role in the development of treatments for older women with osteoporosis.
authors.affiliation: Epidemiology, Demography, and Biometry Program, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA. JAL7@CDC.GOV
authors.forename: J A
authors.initials: JA
authors.lastname: Langlois
authors.forename: C J
authors.initials: CJ
authors.lastname: Rosen
authors.forename: M
authors.initials: M
authors.lastname: Visser
authors.forename: M T
authors.initials: MT
authors.lastname: Hannan
authors.forename: T
authors.initials: T
authors.lastname: Harris
authors.forename: P W
authors.initials: PW
authors.lastname: Wilson
authors.forename: D P
authors.initials: DP
authors.lastname: Kiel
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D012727:Sex Characteristics; D013131:Spine / Q000378:metabolism
chemical_list: D007334:Insulin-Like Growth Factor I