Background: The changes in androgen levels after the menopause and the effects of hormone replacement therapy (HRT) itself and the mode of HRT have not been established. The objectives of this study were to document the effect of age on androgen levels in a normal population of postmenopausal women and to investigate the effect of oral or transdermal HRT on androgen, oestradiol and sex hormone binding globulin (SHBG) values.
Methods: A cross-sectional study was conducted on 182 postmenopausal females aged 45-100 years, randomly recruited from the community. Serum levels of dehydroepiandrosterone sulphate (DHEAS), androstenedione, testosterone, free androgen index (FAI) and SHBG in a reference group of women, subdivided by age, menopausal status, HRT replacement and mode of HRT replacement.
Results: Age was a significant factor affecting androstenedione (<55, > or =55 years) and DHEAS (<65, > or =65 years). HRT status was found to influence values for androstenedione, SHBG and FAI. Neither HRT nor age significantly influenced testosterone.
Conclusions: The observations suggest the need to provide age-specific reference intervals for androstenedione and DHEAS but not for testosterone and SHBG. The significant effect of HRT treatment would also suggest a need for treatment associated reference intervals for androstenedione, SHBG and FAI. Suggested reference intervals for each of these partitioned groups are presented.