Objective: The purpose of this study was to investigate the hormonal changes during the menopausal transition in a non-clinical population.
Methods: Fifty-nine healthy Norwegian women participated in a five year prospective longitudinal study during the transition from pre- to post-menopause, starting one to four years before menopause, and ending one to four years postmenopausal. None of these women were given hormone replacement therapy (HRT). Blood samples were collected every 12 months and luteinizing hormone (LH), follicle stimulating hormone (FSH), steroid hormone binding globuline (SHBG), prolactin (PRL), estradiol (E2), estrone (E1), testosterone, androstendione, dehydroepiandrostendione-sulphate (DHEA-S), and thyroid stimulating hormone (TSH) were analyzed.
Results: The serum levels of FSH and LH, E2 and E1 profile essentially confirmed previous data obtained in cross-sectional studies. A continuous increase in serum FSH and LH and a concomitant fall in E2 and E1 were observed in all women before menopause and in the two postmenopausal years. Both androstendione and testosterone showed a decline three years before menopause. After the menopause, however, there were fluctuations in the testosterone levels. Androstendione correlated positively with both E2 and E1 and testosterone postmenopausally. Body mass index (BMI) did correlate with testosterone, but not with androstendione. BMI correlated negatively with SHBG. No correlation was found between BMI and E2, E1, FSH and LH.
Conclusion: This longitudinal prospective study of hormonal changes during the transition from pre- to postmenopause indicates that not only estrogen hormonal changes, but androgen hormonal changes as well, precedes the menopause by several years.