Low serum concentrations of insulin-like growth factor I are associated with femoral bone loss in a population-based sample of postmenopausal women.
OBJECTIVE
Cross-sectional studies suggest that the decline in insulin-like growth factor-I (IGF-1) levels with age may contribute to age-associated bone loss. However, prospective data on the relation between circulating IGF-I and bone loss in old age have not yet been reported.


METHODS
A longitudinal study (follow-up time 3.3 years) of the change of bone mineral density (BMD) at the lumbar spine and femoral neck in relation to serum IGF-I.


METHODS
A population-based sample of 173 elderly men and 107 postmenopausal women without medical conditions or medication known to significantly affect BMD or serum IGF-I levels.


METHODS
BMD at the lumbar spine and femoral neck at baseline and after a mean follow-up-time of 3.3 years, serum-IGF-I, insulin-like growth factor binding protein 3 (IGFBP-3), sex hormone-binding globulin (SHBG) and biologically available testosterone (BAT).


RESULTS
In women, there was a graded negative relationship between quartiles of serum IGF-I and bone loss at the proximal femur (P = 0.04), which persisted after adjustment for potential covariables of bone loss and serum IGF-I. In subgroup analysis the association between serum IGF-I and change in BMD was only apparent in women more than 10 years past menopause (r = + 0,38, P = 0.01). No association between serum IGF-I levels and changes in BMD was observed in men. IGF-I levels were not associated with changes in spinal BMD.


CONCLUSIONS
Our data suggest that low circulating levels of IGF-I in elderly women are associated with greater femoral bone loss, and support previous findings of gender differences in the relation between serum IGF-I and BMD in older age.
Seck
T
T
Department of Internal Medicine I, University of Heidelberg, 69115 Heidelberg, Germany.
Scheidt-Nave
C
C
Leidig-Bruckner
G
G
Ziegler
R
R
Pfeilschifter
J
J
D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology; D005260:Female; D005272:Femur Neck / Q000503:physiopathology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood* / Q000209:etiology; D012737:Sex Factors
D007334:Insulin-Like Growth Factor I