Endocrine biomarkers and symptom clusters during the menopausal transition and early postmenopause: observations from the Seattle Midlife Women's Health Study.

Objective: During the menopausal transition and early postmenopause, participants in the Seattle Midlife Women's Health Study were likely to belong to one of three symptom severity classes: severe hot flashes with moderate sleep, mood, cognitive, and pain symptoms (high-severity hot flash); moderate levels of all but hot flashes (moderate severity); and low levels of all (low severity). We tested models of the differential effects of hypothalamic-pituitary-ovarian (HPO) axis, hypothalamic-pituitary-adrenal (HPA) axis, and autonomic nervous system (ANS) biomarkers on the three symptom severity classes.

Methods: The Seattle Midlife Women's Health Study participants recorded symptoms monthly in diaries and provided overnight urine samples several times per year that were analyzed for estrone, follicle-stimulating hormone (FSH), cortisol, testosterone, epinephrine, and norepinephrine. Multilevel latent class analysis with multinomial regression was used to determine the effects of HPO axis, HPA axis, and ANS biomarkers on symptom severity class membership.

Results: Having lower estrogen and higher FSH levels was significantly associated with belonging to the high-severity hot flash class versus the low-severity class. Having lower epinephrine and higher norepinephrine levels increased the likelihood of belonging to the high-severity hot flash class versus the low-severity class. Having lower epinephrine levels was significantly associated with belonging to the moderate-severity class versus the low-severity class. Cortisol and testosterone were unrelated to symptom severity class membership.

Conclusions: The association of HPO axis biomarkers (estrogen and FSH) with the high-severity hot flash class is anticipated based on prior hot flash research, and the associations of HPA axis biomarkers are as expected based on earlier laboratory studies. The association of lower epinephrine levels with the moderate-severity class suggests that these symptoms may be mediated by the ANS.