Vertebral morphometry by X-ray absorptiometry: which reference data for vertebral heights?

INTRODUCTION: The recent improvement in the resolution of dual-energy X-ray absorptiometry (DXA) images enables most vertebral levels to be seen adequately and thus DXA may be a worthwhile alternative to radiologic morphometry for the identification of vertebral fractures (VF). In this multicenter study, we have derived reference data for vertebral heights and their ratios in Italian women using morphometric X-ray absorptiometry (MXA). METHODS: DXA scans were acquired in 1254 consecutive pre- and postmenopausal women, (mean age 63.7 ± 11.3, range 26-88 yrs), referred to six osteoporosis centers. MXA analysis of these images was performed by the same operator measuring vertebral heights and height ratios from L4 to T4. We calculated measures of central tendency and dispersion of vertebral heights and vertebral ratios using different approaches (mean and standard deviation as well as median and interquartile range of raw data, mean and standard deviation of trimmed data using an iterative algorithm, and mean and standard deviation of not fractured vertebrae). RESULTS: Independently of the approach that we used, all the measures of central tendency were similar, while significant differences were found when compared with reference ranges in other populations. The vertebral heights of our sample at every vertebral level were significantly smaller than both Rea population and the Lunar reference values, even after normalization. Splitting data according to age groups, there was a decrease in the vertebral heights and ratios between the younger and older women. CONCLUSIONS: This study demonstrates that reference data for MXA should be population specific and age matched.

Morphometric dual-energy X-ray absorptiometry (MXA) for identification of vertebral fractures.

Visual identification of vertebral fractures from spinal radiographs makes use of operator expertise in ruling out non-fracture deformities or normal variants. Morphometric X-ray absorptiometry (MXA) has recently been developed to assess vertebral deformity status quantitatively by dual energy X-ray absorptiometry (DXA). The reliability of MXA measurements depends on the precision of the technique, and this is influenced by system error, variability associated with morphometric analysis, and variability within study populations. This technique has proved to be useful in the identification and evaluation of osteoporotic vertebral deformities in both epidemiologic surveys and clinical trials. The major limitation of DXA vertebral assessment is the poor quality of images of thoracic vertebrae. We conclude that, used as a screening tool, this approach may help to identify vertebral fractures with a reduced radiation dose to the patient, and that technological improvements are necessary to improve image quality.

Raloxifene and cardiovascular health: its relationship to lipid and glucose metabolism, hemostatic and inflammation factors and cardiovascular function in postmenopausal women.

CHD is one of the most common serious chronic conditions in postmenopausal women and leads to extremely high risk for recurrent myocardial infarction and death. On the basis of the currently available randomized clinical-trial results the role of conventional HRT for treatment and prevention of CHD is rapidly evolving from presumed benefit to proven harm, at least in some categories of women yet to define. For this reason there has been a particular interest in potential clinical uses of selective estrogen receptor modulators (SERMs). SERMs are a class of compounds that can act as estrogen receptor (ER) agonists in some domains (bone and lipids) and acting as ER antagonists in others (breast and uterus). Raloxifene hydrochloride is an antiestrogen that is currently approved only to treat osteoporosis in postmenopausal women. Because of its effects on lipids and other biomarkers of cardiovascular risk, there is great interest in determining whether it may benefit the cardiovascular system. The great majority of data on cardiovascular effects of raloxifene concern effects on lipids and markers of thrombosis and inflammation. The purpose of this review is to summarize the best available evidence concerning raloxifene and cardiovascular disease focusing some areas known to be important risk factors for cardiovascular diseases: lipids and lipoproteins, glucose metabolism, hemostatic factors, markers of inflammation and cardiovascular function.

Bone metabolism and mass in women with Cushing's syndrome and adrenal incidentaloma.

OBJECTIVE: The aim of this study was to compare bone turnover and mass in women with either Cushing's syndrome (CS) or adrenal incidentaloma (AI), which is a possible model for minimal hypersecretion of cortisol. DESIGN AND PATIENTS: We studied 15 patients with CS (seven premenopausal and eight postmenopausal women); 23 patients with AI (five premenopausal and 18 postmenopausal women) and 20 matched controls (seven premenopausal and 13 postmenopausal women). Alkaline phosphatase (ALP), bone alkaline phosphatase (bALP), osteocalcin (BGP), 24-h urinary pyridinoline (Pyr) and deoxypyridinoline (D-Pyr) and serum and 24-h urinary calcium and phosphorus were determined in all subjects. Bone mineral density (BMD) at lumbar spine and proximal femur was measured by dual energy X-ray absorptiometry (DEXA). RESULTS: We found a significant reduction of BGP and serum phosphorus in CS and AI (P < 0.05) vs. controls and significantly lower levels of Pyr only in CS (P < 0.05) vs. AI and controls. Spinal and femoral BMD z-values were significantly lower (P < 0.05) in patients with CS (z-score: lumbar spine -1.44 +/- 1.5 and femoral neck -1.07 +/- 1; mean +/- SD) compared to AI and controls. CONCLUSIONS: Our data show that hypercortisolism reduces osteoblastic function and bone resorption and that osteocalcin can contribute to the precocious diagnosis of silent glucocorticoid excess. Patients with active CS were found to have lower BMD, particularly at vertebral level.