Effect of replacement estrogen on insulin-like growth factor-I in postmenopausal women: the Rancho Bernardo Study.
Insulin-like growth factor-I (IGF-I) is associated with protein, carbohydrate, and bone metabolism. Results of previous studies examining the effect of exogenous estrogen on levels of IGF-I have been inconsistent. We examined the cross-sectional association between serum IGF-I levels and hormone replacement therapy (HRT) use in 672 postmenopausal women aged 50 yr and older. The mean age-adjusted IGF-I level was highest in the 415 women who reported never or past HRT use (126.8 micrograms/L), lowest in the 128 women who reported using estrogen alone (99.3 micrograms/L), and intermediate in the 115 women who reported using combination estrogen and progesterone (112.4 micrograms/L). A significant linear decline in mean age-adjusted IGF-I levels by duration of HRT use among all current users was seen. The decrease in serum IGF-I with current use of HRT is not consistent with the fact that both HRT and increased levels of IGF-I have been associated with improved glucose and bone metabolism and lipid profile. Further research is needed to evaluate the effect of the addition of a progestin to oral HRT on IGF-I-induced changes in GH levels.
Goodman-Gruen
D
D
Department of Family and Preventive Medicine, University of California San Diego, La Jolla 92093-0631C, USA.
Barrett-Connor
E
E
D000368:Aged; D003430:Cross-Sectional Studies; D015914:Estrogen Replacement Therapy; D005260:Female; D013006:Growth Hormone / Q000096:biosynthesis; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood*
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone