Objective: To determine whether hormone replacement therapy (HRT) alters glucose metabolism.
Methods: Cross-sectional data from the third National Health and Nutrition Examination Survey (1988-1994) included levels of hemoglobin A(1c) in women with diagnosed diabetes and levels of hemoglobin A(1c), fasting and 2-hour glucose, and fasting insulin and C-peptide in women without diagnosed diabetes. We compared mean values for these measures among never, current, and past users of HRT with adjustment for confounders. Types of hormones were not studied.
Results: Hormone replacement therapy was used by 8. 6% of diabetic women and 16.7% of women without diagnosed diabetes; 19.3% and 18.5%, respectively, had used HRT in the past. Current use approximately doubled among diabetic women between 1988-1991 and 1991-1994. Current users had lower hemoglobin A(1c) and fasting plasma glucose levels but higher 2-hour glucose levels compared with never and past users. After adjustment for confounding factors, hemoglobin A(1c) levels were 0.1% lower, fasting glucose levels were 3 mg/dL lower, and 2-hour glucose levels were 15 mg/dL higher in current users. Fasting serum insulin and C-peptide levels were not associated with HRT use. Duration of HRT use among current users and time since cessation among former users were not associated with measures of glucose metabolism.
Conclusion: The prevalence of HRT in the United States among diabetic women is approximately half that of women without diabetes diagnoses, although it appears to be increasing. Postmenopausal hormones appear to have no adverse effect on basal glucose metabolism but are associated with slightly elevated postchallenge glucose levels.