Variation of urinary follicle-stimulating hormone level after menopause : From the results of Japan Nurses’ Health Study

Abstract

The change in follicle-stimulating hormone (FSH) during the menopausal transition and associations of FSH with various diseases have been assessed by using blood samples. We examined cross-sectionally the variation of FSH levels, associations of estrone and estradiol with FSH, and associations of BMI with these hormones by using urinary samples from peri-and postmenopausal women in Japan. Of 4472 participants in the Urinary Isoflavone Concentration Survey of the Japan Nurses' Health Study, we analyzed urinary levels of estrone, estradiol and FSH in 547 women aged from 45 to 54 years. Urinary FSH levels varied widely in postmenopausal women and the pattern of change in urinary FSH levels seems to be similar to that in blood FSH levels in previous studies. There were no significant differences in age, body mass index (BMI), estradiol, estrone and estradiol/ estrone ratio among three groups according to the tertile of FSH. In postmenopausal women, there were significant associations of BMI with levels of estrone and estradiol, but there was no significant association of BMI with FSH. Studies using urinary samples will allow us to establish a study project as a large-scale population-based study to determine associations between FSH and various diseases after menopause.

Urinary equol levels are positively associated with urinary estradiol excretion in women

“…BMI has been suggested for association with estrogen metabolism 39 . In addition, previously, residential area was moderately associated with EQP statues 17 , and it could affect the association between urinary equol and E2.…”

“…In a previous report, estrogen was associated with age and isoflavones, while smoking was also associated with estrogen and isoflavones 38 . Although an association between EQP statuses and overweight was controversial 39 , a report has shown a moderate correlation between BMI and urinary estrogens in postmenopausal Japanese women 40 . For these reasons, we chose them as covariates.…”

Associations of reproductive factors with postmenopausal follicle stimulating hormone

“…As menopause approaches and follicular estradiol production declines, FSH levels increase in order to maintain estrogen levels, although the level of increase in FSH around the time of the final menstrual period varies among women [ 10 ]. Previous studies have suggested that there are distinct trajectories of FSH change during the menopausal transition, including low, medium, and high rising [ 10 , 11 ]. At the conclusion of the menopausal transition, FSH levels are believed to plateau and gradually decline.…”

“…At the conclusion of the menopausal transition, FSH levels are believed to plateau and gradually decline. However, few studies have directly evaluated FSH function in the years after the menopause transition is complete, though recent evidence suggests that postmenopausal FSH levels between women may vary substantially, independent of estrogens and adiposity [ 1 , 11 ].…”