by Cooper B. Wilhelm
It has been estimated that one in five women over the age of 50 has osteoporosis, but reductions in bone density and strength can start as early as a person's 30's. Although much is known about osteoporosis, a pair of recent studies offers advances in how to monitor and prevent osteoporosis more easily.
Doctors have long recommended weight-bearing exercises, such as jogging and strength training, as ways to improve bone density and strength. However, a new study published in The Journal of Clinical Endocrinology & Metabolism suggests that physical activity in general may provide protection.
In the two-fold study, Saudi Arabian researchers examined the relationship between physical activity and levels of certain natural substances in the blood that are associated with bone loss and growth in 1,235 randomly-selected, premenopausal women. The researchers also followed 58 of those women as they underwent an eight-week training regimen, and compared them to 62 women who remained sedentary.
The researchers found that women who were physically active for more than two hours a week had 36.8% less sclerostin, a protein thought to inhibit bone growth, in their blood. They also had more than double the level of insulin growth factor-1 (IGF-1), a hormone that stimulates bone formation. Furthermore, women who took part in the physical activity training had a 33.9% drop in sclerostin levels over just those eight weeks and an almost three-quarter increase in their levels of SGF-1. Women who were physically active for more than two hours a week also had higher levels of bone formation markers.
From these findings, the researchers concluded "even minor changes" in a person's level of physical activity can affect chemicals in their blood associated with bone loss and growth.
Back stateside, researchers at the University of Pittsburgh have found a way to predict the risk of a future fracture in women as they transition into menopause using a simple urine test.
Previous studies have found that the amount of cross-linked N-telopeptide of type-1 collagen (NTX) in the urine of postmenopausal women could be used to predict their risk of a future fracture. Researchers wanted to see if the same chemical could also be used to identify premenopausal women who are particularly at risk.
For an average of 7.6 years, the researchers followed 2,305 women from all over the United States before and after menopause. All the women in the study were between the ages of 42 and 52, and were still menstruating three months before testing began.
The researchers found that women who later reported having fractures had had a median 9.9% more NTX in their urine at the start of the study. They also found that woman who had a level of NTX in their urine above the median at the start of the study had a 59% greater risk of experiencing a fracture than woman whose level had been below median. On the whole, women whose NTX levels had an above-median change during the study were 50% more likely to experience a fracture, regardless of their initial NTX level.
The density of bones in the spine was also predictive. Women with elevated NTX levels who also had a very low bone mineral density in the lumbar spine were almost three times more likely to experience a fracture. Strangely, bone density of the hip was not associated with fracture risk either way.
In a press release from the University of Pittsburgh Medical Center, lead author Dr. Jane Cauley, a professor of epidemiology at the University of Pittsburgh Graduate School of Public Health, said "Knowing a woman's risk of fracture can help doctors determine the best course of action to protect her bones as she enters menopause, a time when estrogen deficiency negatively affects skeletal health."
Last Reviewed on August 23, 2012
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