Use of Peripheral Bone Density Measurements
February 1, 2002
Use of Peripheral Bone Density Measurements
Abstract & Commentary
Synopsis: The prevalence of unsuspected low bone density is high enough to warrant detection and treatment. Lower cost measurements of peripheral bone are effective.
Source: Siris ES, et al. JAMA. 2001;286:2815-2822.
Siris and colleagues reviewed data from the National Osteoporosis Risk Assessment (NORA) study to identify the prevalence of low bone density and the efficacy of peripheral bone measurements. This study that began in 1997 is longitudinal in design, following more than 200,000 postmenopausal women in primary care practices. Peripheral bone density was measured with several methods: forearm using pDEXA from Norland (67,566 women), finger using AccuDEXA from Schick (15,011 women), or heel using either Osteoanalyzer from Siemens-Osteon (107,897 women), or Sahara from Hologic (9686 women). Overall, 39.6% of the women had osteopenia and 7.2% had osteoporosis. Native Americans had the same risk of osteoporosis as Caucasians, Asians and Hispanics had higher risks, and African-Americans had a lower risk. However, the likelihood of fracture was lower for Asians and no different for Hispanics compared with Caucasians. The current use of estrogen was associated with 73% reduced risk of osteoporosis (odds ratio, 0.27; confidence interval [CI] = 0.25-0.28). Women with osteopenia had a 1.8-fold higher risk of fracture, and those with osteoporosis had a 4-fold higher risk. The factors associated with an increased risk of low bone density were low body weight, maternal history of osteoporosis or fracture, personal history of fracture, smoking, lack of exercise, use of glucocorticoids, and nonuse of estrogen. A lower percentage of women tested with heel ultrasonography (Sahara) were identified as having osteoporosis (3.4%). Measurement of bone density at the finger yielded the highest percentage (13.5%).
Comment by Leon Speroff, MD
I am often asked about the value of office-based bone density machines. There is a good-sized literature establishing the fact that peripheral bone mineral density can be used to assess fracture risk with one exception. The exception is hip fracture risk, which is best assessed with direct measurements of hip density, and this is the reason there has been reluctance to promote the machines that measure peripheral bone density. However, this study indicates that the peripheral machines do a good job, with the method that uses a finger doing the best. This is believed to be due to the ability to immobilize a finger in a standard fashion, minimizing variability.
In this large cohort of postmenopausal women without known bone status, almost half had low bone density measurements and about 7% had osteoporosis. It is reasonable to assume that these percentages underestimate the general prevalence in America because women who had a recent bone density measurement or who were being treated for osteoporosis were excluded from the study. The fracture rates are also an underestimation because nonclinical, asymptomatic spinal fractures could not be detected in this study. Even though the risk of osteoporosis for African-American women was about half that of Caucasian women, they had a 32% prevalence of osteopenia and a 4% incidence of osteoporosis, still high enough to represent significant fracture risk.
Clinical lesions from this study:
- The prevalence of unsuspected low bone density is relatively high;
- A fracture means osteoporosis until ruled otherwise;
- No single bone density measurement will identify all women at risk of fracture;
- Peripheral measurements of bone density have a predictive value very similar to that of central measurements;
- Finding a low bone density by any method indicates a high risk of fracture within the following year.
For these reasons, an inexpensive method to measure bone density in a clinician’s office is an effective method to prevent osteoporotic fractures. Identifying these patients and providing preventive therapy with one of the many options available today are important obligations for clinicians who care for postmenopausal women. Measuring bone density in a finger by ultrasound is a method with great potential because it is relatively inexpensive, has a high-detection rate with good correlation with fracture risk, and minimizes individual variability.1
Reference
1. Mauloni M, et al. Menopause. 2000;7:402-412.
Dr. Speroff is Professor of Obstetrics and Gynecology, Oregon Health Sciences University, Portland, OR.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content