Menopause is defined as the 12 month period after a women has her last menstrual period. The time leading up to menopause (perimenopause) can last for a total of four to eight years, but varies with each individual. During this time, a woman's ovarian function begins to decline, decreasing the amount of hormone released and increasing bone loss.
A study aimed to specify the amount of bone density loss during menopause, found that the decline in bone mineral density began before the final menstrual period (FMP). The authors divided the FSH levels of menopause into categories, with four different requirements. Stage 1,2,3, and 4, depending on the amount of FSH present. In Lumbar Spinal regions, the bone loss was measured in relation to the FSH levels and stages. In stage one (7 years before the FMP), 17% of bone was lost, in stage two (7-2 year before FMP), 44% of bone was lost. In the last two FSH stages, from 2 years until FMP to 6 years after FMP, bone loss increased exponentially.
When comparing BMI, the study found that obeseity protected women from bone loss during perimenopuse, as compared to non-obese women who lost more bone mass. The authors predicted this difference was due to estradiol (a hormone that can reverse symptoms of menopause) and other hormones in adipose tissue around the body.
Bone loss in women experiencing menopause is extensive. This loss in bone density can increase risk of osteoporosis, fractures or other injuries. Recent findings have increased the hope for treatment of post-menopausal osteoporosis. Researchers at Tokyo Medical University believe that Sema3A (a protein secreted by osteocytes) could reverse this problem. They found that drop off of estrogen levels caused a decrease in Sema3A. Sema3A is important for maintaining bone and bone density, without this protein, osteocytes begin to die and bones deteriorate. This could be an important finding for treatments and prevention of menopausal osteoporosis.
How does estrogen protect bones? Unraveling a pathway to menopausal bone loss. (2019, April 11). Women's Health Weekly, 425. https://link.gale.com/apps/doc/A581549939/ITBC?u=regis&sid=ebsco&xid=418eeb7f
Sowers, M. R., Zheng, H., Jannausch, M. L., McConnell, D., Nan, B., Harlow, S., & Randolph, J. F., Jr (2010). Amount of bone loss in relation to time around the final menstrual period and follicle-stimulating hormone staging of the transmenopause. The Journal of clinical endocrinology and metabolism, 95(5), 2155–2162. https://doi.org/10.1210/jc.2009-0659
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