Gender-specific relationship between serum free and total IGF-I and bone mineral density in elderly men and women
OBJECTIVE: Little is known about the association between free IGF-I levels and bone mineral density (BMD). DESIGN: A cross-sectional study of 218 healthy subjects (103 men, 115 women, age 55-80 years) was carried out. METHODS: Fasting serum free IGF-I, total IGF-I, estradiol and sex hormone-binding globulin (SHBG) levels were measured. The ratio of estradiol to SHBG was used as an index of free estradiol. BMD measurements were performed by dual-energy X-ray absorptiometry of the lumbar spine and the proximal femur. RESULTS: In multivariate analyses with BMD of the lumbar spine as the dependent variable and serum free IGF-I, age, body mass index (BMI) and the free estradiol index as independent variables, the free IGF-I was positively related to the BMD of the lumbar spine in men (P = 0.02) but not in women. When the same analyses for the lumbar BMD were performed with total serum IGF-I the association was also only statistically significant in men (P = 0.05). In multivariate analyses with the trochanter BMD as the dependent variable and serum free IGF-I, total IGF-I, age, BMI and the free estradiol index as independent variables, the associations between (free and total) IGF-I and the trochanter BMD in men was of borderline significance. CONCLUSIONS: In elderly men free and total IGF-I were positively related to lumbar BMD, while (free and total) IGF-I was borderline positively related to trochanter BMD. As these relationships were not observed in elderly women, we suggest a weak gender-specific anabolic effect of IGF-I on BMD on trabecular bone.
|Keywords||Aged, Aged, 80 and over, Aging/*metabolism, Bone Density/*physiology, Female, Humans, Insulin-Like Growth Factor I/*metabolism, Lumbosacral Region, Male, Middle Aged, Research Support, Non-U.S. Gov't, Sex Distribution|
Janssen, J.A.M.J.L., Burger, H., Stolk, R.P., Grobbee, D.E., de Jong, F.H., Lamberts, S.W.J., & Pols, H.A.P.. (1998). Gender-specific relationship between serum free and total IGF-I and bone mineral density in elderly men and women. European Journal of Endocrinology. Retrieved from http://hdl.handle.net/1765/8868