Bone mineral density and follicle-stimulating hormone levels

Menopause-related loss of spine and hip bone mineral density (BMD) is linked to both low estradiol and higher follicle-stimulating hormone (FSH) levels, according to a cross-sectional study in the International Journal of Environmental Research and Public Health.

The authors noted that estradiol is considered the most critical factor in menopause-associated decrease in BMD, but also that the role of increasing FSH during menopause is relatively unclear.

For the study, 141 healthy women, aged 30 to 70 years, from Colorado were classified to 1 of 5 menopausal status groups based on self-reported menstrual cycle history: premenopausal (n = 30), early perimenopausal (n = 31), late perimenopausal (n = 30), early postmenopausal (n = 24), and late postmenopausal (n = 26).

Spine/hip BMD and sex hormones were measured on all women using dual-energy x-ray absorptiometry and enzymatic/colorimetric methods, respectively.

Compared with early perimenopausal women, spine BMD was lower (P< .05) in late perimenopausal, early postmenopausal, and late postmenopausal women, whereas hip BMD was lower (P < .05) among early postmenopausal and late postmenopausal women.BMD also was inversely associated with FSH (spine: bivariable coefficient of determination [r] = −0.341; and hip: r = −0.271 [P< .05]).

In addition, BMD was directly associated with estradiol (spine: r = 0.274; and hip: r = 0.256 [P < .05]).

The authors corroborate previous data indicating that menopause seems to be a vulnerable period for bone loss, even in healthy women.

However, unlike some human and animal studies that show a menopause-associated decline in physical activity, the current study found no significant difference in self-reported leisure time physical activity among menopausal stages. “Furthermore, physical activity was not correlated with BMD nor did it influence the associations of FSH or estradiol with BMD,” they wrote.

The authors acknowledged that physical inactivity can exacerbate BMD decline and increase fracture risk; however, to determine whether menopause contributes to declines in physical activity after menopause requires a larger cohort study using a more accurate measure of physical activity, such as accelerometry.

Despite the study finding statistically significant correlations between BMD and FSH and estradiol, the values were weak and thus the results should be interpreted cautiously, according to the authors.

The study is also a secondary analysis of baseline dual-energy x-ray absorptiometry data from a previous study on the biological mechanisms underlying vascular dysfunction with estrogen deficiency and aging in healthy women. That study was not powered to determine differences in BMD in spine and hip sites nor to test the associations of BMD with FSH or other sex hormones.

Moreover, the current study has a cross-sectional study design, which precludes discussion of causality. In addition, mass spectrometry might have provided more precise measurements of estradiol, especially in peri- and postmenopausal women.

For instance, 28 of the 141 women included in the analysis had estradiol levels below the lower limit of detection, 10 pg/mL, for which a value of 10 pg/mL was assigned.

“Future studies are essential to delineating the mechanisms by which FSH regulates bone health in aging women,” the authors wrote.

Reference
Park YM, Jankowski CM, Swanson CM, Hildreth KL, Kohrt WM, Moreau KL. Bone mineral density in different menopause stages is associated with follicle stimulating hormone levels in healthy women. Int J Environ Res Public Health. Published online January 29, 2021. doi:10.3390/ijerph18031200