The Effect of Estrogen Use on Levels of Glucose and Insulin and the Risk of Type 2 Diabetes in American Indian Postmenopausal Women
The Strong Heart Study
- Ying Zhang, PHD,
- Barbara V. Howard, PHD2,
- Linda D. Cowan, PHD3,
- Jeunliang Yeh, PHD1,
- Carl F. Schaefer, PHD1,
- Robert A. Wild, MD4,
- Wenyu Wang, PHD1 and
- Elisa T. Lee, PHD1
- 1Center for American Indian Health Research, University of Oklahoma Health Sciences Center (HSC), Oklahoma City, Oklahoma
- 2MedStar Research Institute, Washington, DC
- 3Department of Biostatistics and Epidemiology, University of Oklahoma HSC, Oklahoma City, Oklahoma
- 4Section of Reproductive Endocrinology, Department of Obstetrics/Gynecology, University of Oklahoma HSC, Oklahoma City, Oklahoma
Abstract
OBJECTIVE—To examine the associations between estrogen use and levels of insulin and glucose as well as the effect of estrogen use on the risk of type 2 diabetes.
RESEARCH DESIGN AND METHODS—This report is based on 857 women who were both nondiabetic and postmenopausal at the baseline examination (1989–1992) and who completed a second examination (1993–1995) an average of 4 years later. The participants were divided into three groups: never, past, and current users based on their baseline estrogen use status. ANCOVA was used to compare the insulin and glucose levels among estrogen use groups. Logistic regression was used to evaluate the association between estrogen use and the incidence of type 2 diabetes.
RESULTS—Postmenopausal estrogen use was associated with lower fasting glucose (0.2 mmol/l lower) but higher 2-h glucose levels (0.4 mmol/l higher) compared with never users. It was not significantly associated with the risk of type 2 diabetes compared with past and never users, based on American Diabetes Association or World Health Organization definitions of diabetes or on only a 2-h glucose level ≥11.1 mmol/l. However, the risk of type 2 diabetes increased with increasing duration of estrogen use among current users, with an odds ratio of 1.10 per year of use (95% CI: 1.01–1.19).
CONCLUSIONS—The data suggest that estrogen use in American Indian postmenopausal women may relate to deterioration of glucose tolerance. Longer duration of estrogen use among current users may relate to an increased risk of type 2 diabetes.
Footnotes
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Address correspondence and reprint requests to Ying Zhang, PhD, Center for American Indian Health Research, University of Oklahoma HSC, P.O. Box 26901, Oklahoma City, OK 73190. E-mail: ying-zhang4{at}ouhsc.edu.
Received for publication 22 June 2001 and accepted in revised form 13 December 2001.
The views expressed are those of the authors and do not necessarily reflect those of the Indian Health Service.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
- DIABETES CARE
