New findings from non-linear longitudinal modelling of menopausal hormone changes.

Changes in FSH and estradiol (E2) across the menopausal transition are clearly not linear. The present study utilizes data from 204 women who completed the 13-year prospective Melbourne Women's Midlife Health Project. E2, FSH, symptoms, self-rated health, mood, sexual function and coronary heart disease (CHD) risk were measured longitudinally. We presumed an s-shaped curve for each hormone and estimated five parameters for each hormone curve for each woman: baseline, final value, range, slope at inflexion point and age at inflexion point. These parameters were found to adequately estimate the curve for each hormone. The median age of transition observed for E2 occurs >1 year later than the median age of transition observed for FSH. FSH parameters did not affect any of the health outcomes analysed. Hot flushes, night sweats, sleeping problems, vaginal dryness and to a lesser extent self-rated health were highly significantly associated with E2 range and slope. Sexual response and CHD risk were highly significantly associated with final E2 level (post-menopausally). These findings have clinical relevance in identifying which symptoms will be triggered by steep transitions of E2 such as sudden withdrawal and which health parameters may require a maintenance level of E2.