Perhaps you've been told—or you've read—that osteopenia presents a serious risk factor for the development of osteoporosis. Or perhaps you've had a bone density test and your doctor has told you that the results mean you have osteopenia. If so, you probably have questions. Here are some basics on osteopenia.
Osteopenia is a word coined by the World Health Organization (WHO) that doesn't mean anything in particular other than a specific category of T-scores, corresponding to a bone density value between 1 and 2.5 standard deviations below the average value at peak bone mass.
WHO originally set up T-scores as an epidemiologic tool to measure rates of low bone density across countries. T-scores were never intended to be used to label individual patients with some kind of diagnosis.
Another important caveat is that the data being reviewed at the time by WHO experts was all collected from postmenopausal Caucasian women. The WHO researchers looked at this data set, looked at the relationship between T-scores and fractures and said, "Well, what cut point should we use to define osteoporosis?" They picked -2.5 because about a third of postmenopausal women will have a T-score below -2.5, and the lifetime risk of fracture for a 50-year-old Caucasian woman is around 39 percent.
Their thinking went this way: "If we pick -2.5, this gives us a prevalence of osteoporosis that is approximately equal to the lifetime risk of fracture for a woman at the time of menopause." This seemed like a rational cut point to examine rates of osteoporosis across countries. Then the researchers decided to devise a middle category of bone density to avoid having simply "normal" and "osteoporosis" categories. So, they decided to make a middle category of T-scores between -1 and -2.5 and labeled this category "osteopenia."
Many osteoporosis experts would like to see the term osteopenia just fade away because it is confusing to both patients and health care professionals. All it means is that a person's T-score is between -1.0 and -2.5. Perhaps "osteopenia" should be replaced with a term like "low bone density," so people to focus on their 10-year risk of fracture and not worry about their specific bone-density category as defined by T-score.
Posted June 3, 2011 Johns Hopkins Health Alerts © 2011 Remedy Health Media