Bone mineral density measurement

Peripheral bone mineral density measurements cannot be used for diagnosis because they do not correlate with central measurements. However, they are useful in identifying patients who are candidates for central DXA and who are at increased risk of fracture.5 It also may be useful in patients who have had multiple fractures or in low-risk patients. Additionally, peripheral measurement of bone mineral density generally is less expensive than central DXA and is easily accessible. Instruments used for peripheral bone densitometry are portable, which allows bone density to be measured in pharmacies and health-fair screening booths. 

Powles TS, Hickish T, Kanis JA, et al. (1996) Effect of tamoxifene on bone mineral density measured by dual energy X-ray absorciometry in healthy premenopausal and postmenopausal women. J Clin Oncol 14 78-84... 

The effects of inhaled glucocorticoids on bone mineral density (measured using dual X-ray absorptiometry of the spine and hip) and biochemical parameters were followed over 18 months. Mean serum osteocalcin concentrations were significantly lower in patients taking beclomethasone dipropionate or budesonide at doses of 800 micro-grams/day and more. However, bone mineral density of the lumbar spine and hip was not affected. The normal advancement of bone mineral density expected in growing children was not affected by inhaled glucocorticoids taken for 7-16 months (SEDA-22,184). 

Bone mineral density (measured by dual X-ray absorptiometry) did not change significantly in asthmatic... 

In a prospective randomized comparison of the effects of fluticasone propionate 1000 micrograms/day and budesonide 1600 micrograms/day, over 1 year, bone mineral density measured in the spine was normal at the start of the study and increased slightly with time in both groups, as did serum osteocalcin concentration. 

Postmenopausal women with intact parathyroid glands on prolonged suppressive levothyroxine therapy may be more susceptible to osteoporosis and should have their bone mineral density measured and/or take preventive osteoporosis therapy. Cautious use of levothyroxine, avoiding overdosage and unnecessary use, is probably safe for bone. 

Bone mineral density (measured by dual X-ray absorptiometry) did not change significantly in asthmatic children treated for 3-6 years with a mean daily dose of 504 micrograms (189-1322 micrograms) budesonide (85). 

Preliminary results that suggested coumarin-associated reduction in bone density have not been confirmed. In a study from the Osteoporotic Fractures Research Group, 6201 postmenopausal women who were either users (n = 149) or non-users of warfarin were assessed for fractures and bone mineral density. Over 2 years, the two groups had similar age-adjusted heel and hip bone mineral density measurements. During an average of 3.5 years, non-traumatic, non-vertebral fractures occurred in 10% of warfarin users and 9.3% of non-users (67). 

Women older than 65 years of age or yonnger with risk factors for osteoporosis shonld have their bone mineral density measured. Although bone densitometry has been shown to predict fractures, at present there are no guidelines for follow-up bone mineral density testing. However, in women with significant bone loss, repeat testing should be performed as clinically indicated. 

Feldstein A, Elmer PJ, Orwoll E, et al. Bone mineral density measurement and treatment for osteoporosis in older individuals with fractures A gap in evidence-based practice guideline implementation. Arch Intern Med 2003 163 2165-2172. 

Monitor for acute and chronic adverse effects of AEDs. Acute adverse effects are best detected by a thorough neurologic examination at clinic visits. Instruct patients to report sedation, ataxia, rash, or other problems immediately. Monitor for chronic adverse effects including a loss of bone mineral density, which should be measured every 2 years in patients taking phenytoin, phenobarbital, carbamazepine, and valproate. 

Bone mineral density can be measured at various sites throughout the skeletal system and by various methods. The site of measurement can be either central (hip and/or spine) or peripheral (heel, forearm, or hand). Dual-energy x-ray absorptiometry (DXA) can be used to measure central and peripheral sites of bone mineral density. Quantitative ultrasound, peripheral quantitative computed tomography, radiographic absorptiometry, and single-energy x-ray absorptiometry are used to measure peripheral sites. 

The Z-score is a similar measure that is corrected for age and sex of the patient. The Z-score is defined as the number of standard deviations from the mean bone mineral density of age- and sex-matched controls. In premenopausal women, men under age 50, and patients who may have secondary causes for low bone mineral density, Z-scores may be more clinically relevant in evaluating bone mineral density. 

Although increases in bone mineral density have been reported at other sites, most of the clinically significant fractures occur in the hip or spine, and these sites have become clinically important measures in the trials. These increases in bone mineral density are an important marker of treatment effects and are related to the benefits found in larger trials of decreased fracture risk. 

Although most fragility fractures in women occur after age 50, certain groups of premenopausal women are at high risk for osteoporosis. The NOF recommends measuring bone mineral density in premenopausal women with risk factors in addition to sex and race, in whom treatment would be considered.1 Premenopausal women at risk for osteoporosis should follow all nonpharmacologic recommendations for exercise and adequate calcium and vitamin D intake. Currently, no good data... 

Bone mineral density should be measured in women older than 65 years and in women younger than 65 years with risk factors for osteoporosis. Repeat testing should be done as clinically indicated. 

Genant HK, Lang T, Fuerst T, Pinette KV, Zhou C, Thiebaud D, Dfez-Perez A (2004) Treatment with raloxifene for two years increases vertebral bone mineral density as measured by volumetric quantitative computed tomography. Bone 35 1164-1168... 

Marshall D, Johnell O, Wedel H (1996) Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. Br Med J 312 1254-1259... 

All women included in MORE met criteria for osteoporosis defined as a lumbar spine or femoral neck bone mineral density (BMD) T score equal to or less than 2.5 or as the presence of a radiographic vertebral fracture. These women are considered to be at lower risk for breast cancer than women with normal BMD since this parameter could partially reflect a woman s lifetime exposure to estrogens (Zhang et al. 1997). After the start of MORE, NHANES III criteria standardizing total hip BMD measurements became available allowing part of... 

Bone mineral density (BMD) measured using dual x-ray absorptiometry (DEXA) is the current standard method by which to assess BMD in children and adolescents (Loud and Gordon, 2006). It has some limitations in that it only measures bone in two dimensions (g/cm ) and by utilizing the projected area for areal measurements does not account for bone volume or distance of the subject from the beam [i.e., surrounding tissue mass and (re)positioning]. Moreover, the continuous changes in... 

Osteoporosis is a metabolic bone disease characterized by low bone mass and micro-architectural deterioration of bone tissue. This will lead to bone fragility and consequent increase in bone fracture risk. Mean bone mineral density (BMD) is measured with dual X-ray absorptiometry (DEXA) and expressed in Tsc (Tscore). WHO standards are a Tsc that is 1 standard deviation (SD) below mean BMD is graded as normal bone, Tsc between 1 and 1.5 SD below mean BMD is graded as osteopenia and a Tsc of more than 2.5 SD below mean BMD is graded as osteoporosis. When the Tsc is below 1.5 SD mean BMD prevention of osteoporosis must be initiated. Primary osteoporosis is caused mainly by hormone deflciency in both women and men. Secondary osteoporosis may result from endocrine, metabolic, nutritional and autoimmune causes or from immobility because of trauma. Also the use of medicaments such as corticosteroids may be contributing. 

Clinical trials have been reported, and these are not subject to the same levels of uncertainty. They have concentrated on bone mineral density, because this parameter is an acceptable measure of bone mass, is sensitive to the occurrence of osteoporosis and correlates well with the likelihood of bone fracture in patients affected by osteoporosis. Bone mineral density is known to increase in childhood and adolescence, to reach a maximum around the age of 40, then to decline [110,111]. In women in the years immediately following the menopause, it may sharply reduce, and if it reaches a level TA standard deviations below the young adult mean value, the condition is defined by the WHO as osteoporosis [110,111]. 

While biochemical markers of bone metabolism may be sensitive to the effects of glucocorticoids in the short term, the relation between changes in these markers and intermediate measures, such as bone mineral density, and the more important clinical outcomes of fractures, is unknown. In a random stratified sample of 3222 women in the perimenopausal age range (47-56 years), including 119 women with asthma, bone mineral density was measured to determine whether asthma was a risk factor of osteoporosis and to investigate the effect of inhaled glucocorticoids (102). The subjects had predominantly adult-onset asthma, as the age at diagnosis was over 40 years. There were 26 patients who were treated mainly with... 

Bone mineral density has been measured in a 3-year prospective study in 109 premenopausal asthmatic women,... 

In a small cross-sectional study, bone mineral density was studied in 20 prepubertal asthmatic patients treated with moderate to high doses of inhaled glucocorticoids (under 400 micrograms/day beclomethasone or budesonide or over 200 micrograms/day fluticasone) (114). Volumetric trabecular bone mineral density of the lumbar spine and distal radius were measured using dual energy X-ray absorptiometry and were within the reference ranges. 

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