A randomized, double-blind study comparing the effects of beclomethasone and fluticasone on bone density over two years.
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Cross-sectional studies have suggested that asthmatic patients receiving high dose inhaled corticosteroids and intermittent courses of oral corticosteroids have reduced bone mass. This prospective 2-yr study was undertaken to evaluate changes in bone density of patients receiving high doses of inhaled corticosteroids. Patients (n = 33) (males aged 18-50 yrs, females aged 18-40 yrs) on inhaled corticosteroids 1,000-2,000 microg x day(-1), were randomized in a double-blind fashion to either fluticasone propionate (FP) 1,000 microg x day(-1) or beclomethasone dipropionate (BDP) 2,000 microg x day(-1). In parallel, three open control groups of the same age range were studied: asthmatics (n = 8) receiving low dose inhaled corticosteroids (< or =400 microg x day(-1)) (group A); chronic, severe asthmatics (n = 8) receiving oral corticosteroids (> or =10 mg x day(-1) (group B); and healthy untreated volunteers (n = 7) (group C). Bone densitometry scans (quantitative computed tomography (QCT) of spine; dual X-ray absorptiometry of spine, femoral neck, and single photon absorptiometry of forearm) were performed at baseline and after 6, 12 and 24 months of treatment. Biochemical bone marker measurements (serum osteocalcin, bone alkaline phosphatase, pro-collagen type 1 carboxy terminal propeptide, deoxypyridinoline and C-telopeptide of type 1 collagen) were collected every 3 months. Fifteen FP (mean age 36 yrs, six male) and 9 BDP patients (mean age 33 yrs, five male); completed the study. At 0 months, mean bone mineral density (BMD) was lower in patients receiving inhaled corticosteroids (both low dose and high dose) than in normal volunteers. In the FP-treated group, mean vertebral trabecular BMD quantitative computed tomography remained stable with no evidence of decline, whereas there was some decline in the BDP-treated group. The treatment difference between FP and BDP was statistically significant in favour of FP for quantitative computed tomography measurements after 12 months (p = 0.006) and 24 months (p = 0.004). This study suggests that over 24 months, changes in bone density are minimal in patients on high-dose inhaled corticosteroids. (+info)
Inhibitory effect of vitamin K2 (menatetrenone) on bone resorption in ovariectomized rats: a histomorphometric and dual energy X-ray absorptiometric study.
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To clarify how vitamin K2 prevents bone loss in vivo, it was given to ovariectomized 20-week-old rats for 2 weeks. Bone mineral density (BMD) in the whole femur and in 7 specific portions (F1 to F7 from the proximal to the distal end) was determined by dual-energy X-ray absorptiometry, and histomorphometry was also performed in proximal tibial metaphysis. Ovariectomy (OVX) resulted in significant decreases in the BMD in the whole femur and the F1, F2, F6 and F7 portions. Histomorphometrical analysis of the tibia showed that the bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N) were decreased, while trabecular separation (Tb.Sp) and osteoclast number/bone surface (Oc.N/BS) were increased by OVX. The parameters for bone formation were not changed by OVX. These data indicate that the bone loss within 2 weeks is due to the enhancement of bone resorption. Vitamin K2 at 50 mg/kg inhibited the decrease in the BMD of the whole femur together with the F6 and F7 portions. Vitamin K2 also inhibited the decrease in Tb.N and the increases in Tb.Sp, Oc.N/BS and osteoclast surface/bone surface (Oc.S/BS) caused by OVX. These results suggest that vitamin K2 prevents bone loss through the inhibition of bone resorption and osteoclast formation in vivo. (+info)
Bone mineral status in 134 patients with cystic fibrosis.
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AIM: To investigate bone mineral status in patients with cystic fibrosis (CF). PATIENTS AND METHODS: Whole body bone mineral content (BMC), projected bone area, and bone mineral density (BMD) were determined by dual energy x ray absorptiometry in 134 patients with CF and compared with 396 healthy controls. RESULTS: In patients 19 years of age, BMD and BMC for age were significantly reduced. CONCLUSION: Short and narrow bones were the main reasons for reduced BMC for age in patients +info)
Usefulness of quantitative heel ultrasound compared with dual-energy X-ray absorptiometry in determining bone mineral density in chronic haemodialysis patients.
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BACKGROUND: Reduced bone mineral density (BMD) is associated with renal osteodystrophy and osteoporosis in end-stage renal failure patients. Dual-energy X-ray absorptiometry (DXA) is the standard non-invasive method to assess BMD, but is not always widely available. Quantitative heel ultrasound (QUS) is a mobile, relatively inexpensive, easy to perform and radiation-free method which can predict fractures to the same extent as DXA. This study assessed the usefulness of QUS vs DXA in determining BMD in chronic haemodialysis patients. METHODS: Patients had their BMD at the hip and spine measured by DXA (Lunar Expert). QUS of the left heel (McCue CubaClinical II machine) measured broadband ultrasound attenuation (BUA) and velocity of sound (VOS). Correlations between DXA and QUS parameters were calculated. Receiver operator characteristic (ROC) curves were plotted for BUA and VOS and used to define cut-off points for calculating sensitivities and specificities for BUA and VOS. Femoral neck BMD was applied as the standard for diagnosing osteoporosis (T< or =-2.5) and osteopaenia (T>-2.5 and < or =-1) by WHO criteria. RESULTS: Eighty eight patients (45.5% women), mean age 58+/-17 years, were studied. A total of 19% and 49% had femoral neck BMDs in the 'osteoporosis' and 'osteopaenia' ranges, respectively. There were good correlations between hip BMD and QUS parameters (r=0.68-0.79, P<0.001). Areas under the ROC curves for BUA and VOS in diagnosing 'osteoporosis' were 0.86 and 0.80, respectively. BUA and VOS had sensitivities of 76 and 71% and specificities of 80 and 69%, respectively, for diagnosing 'osteoporosis'. The positive predictive values for BUA and VOS were 48 and 35%, respectively, and the negative predictive values were 93 and 91% respectively. CONCLUSIONS: DXA and QUS parameters were significantly correlated. However, sensitivities and specificities of QUS parameters were not sufficiently high for QUS to be used simply as an alternative to DXA. The relatively high negative predictive values suggest that QUS may reliably screen out patients unlikely to have a BMD in the osteoporotic range. The relatively low positive predictive values, however, mean that subjects classified as osteoporotic using QUS require further investigations such as DXA to confirm the diagnosis. (+info)
Risk factors for reduced bone density in haemodialysis patients.
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BACKGROUND: Renal osteodystrophy may result in considerable morbidity for patients with end-stage renal disease. Secondary hyperparathyroidism, adynamic bone disease and osteomalacia, the main bony problems in chronic renal failure, may all be responsible for a reduction in bone mineral density (BMD). This can result in an increased fracture risk. By virtue of their age, post-menopausal status (in women), sedentary life-style and treatment (including previous corticosteroids), haemodialysis patients may be expected also to be at risk for developing osteoporosis, but little is known about the relative importance of these factors. METHODS: We report a prospective study examining the prevalence of reduced bone mineral density (BMD) and its association with a wide range of factors, in a heterogenous group of 88 chronic haemodialysis patients. Femoral neck and lumbar BMD were measured by dual-energy X-ray absorptiometry (DXA). Stepwise multiple linear regression analysis was used to identify risk factors associated with low bone mass. RESULTS: Forty three patients (48.9%) had reduced BMD, and in 17 (19.3%) BMD was below the fracture threshold as defined on DXA measurements by the World Health Organization (WHO). The BMD had significant negative associations with age, serum parathyroid hormone (PTH) levels, current gastric acid suppression therapy, female gender, age at menarche and history of previous fracture. Positive associations were found with weight, haemoglobin concentration, average serum phosphate, weekly heparin dose, oral calcium supplementation and history of parathyroidectomy. CONCLUSIONS: We have confirmed the importance of PTH-related bone disease in affecting BMD in haemodialysis patients, but have found that some other factors, which are known to be risk factors for osteoporosis, are also important. (+info)
Dual energy X-ray absorptiometry assessment of fat mass distribution and its association with the insulin resistance syndrome.
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OBJECTIVE: To determine which dual energy X-ray absorptiometry (DXA)-derived indices of fat mass distribution are the most informative to predict the various parameters of the metabolic syndrome. RESEARCH DESIGN AND METHODS: A total of 87 healthy men, 63 lean (% fat < or =26) and 24 obese (% fat >26), underwent DXA scanning to evaluate body composition with respect to the whole body and the trunk, leg, and abdominal regions from L1 to L4 and from L3 to L4. These regions were correlated with insulin sensitivity determined by the euglycemic-hyperinsulinemic clamp, insulin area under the curve after oral glucose tolerance test (AUC I); triglyceride; total, HDL, and LDL cholesterol; free fatty acids; and blood pressure. The analyses were performed in all subjects, as well as in lean and obese groups separately. RESULTS: Among the various indices of body fat, DXA-determined adiposity in the abdominal cut at L1-4 level was the most predictive of the metabolic variables, showing significant relationships with glucose infusion rate ([GIR], mg kg(-1) lean body mass x min(-1)), triglyceride, and cholesterol, independent of total-body mass (r = -0.267, P<0.05; r = 0.316, P<0.005; and r = 0.319, P<0.005, respectively). Upon subanalysis, these correlations remained significant in lean men, whereas in obese men, only BMI and the amount of leg fat (negative relationship) showed significant correlations with triglyceride and cholesterol (r = 0.438, P<0.05; r = 0.458, P<0.05; r = -0.439, P<0.05; and r = -0.414, P<0.05, respectively). The results of a multiple regression analysis revealed that 47% of the variance in GIR among all study subjects was predicted by AUC I, fat L1-4, diastolic blood pressure (dBP), HDL, and triglyceride as independent variables. In the lean group, fat L1-4 alone accounted for 33% of the variance of GIR, whereas in obese men, AUC I and dBP explained 68% of the variance in GIR. CONCLUSIONS: The DXA technique applied for the evaluation of fat distribution can provide useful information regarding various aspects of the insulin resistance syndrome in healthy subjects. DXA can be a valid, accurate, relatively inexpensive, and safer alternative compared with other methods to investigate the role of abdominal body fat distribution on cardiovascular risk factors. (+info)
Comparison of techniques to estimate total body skeletal muscle mass in people of different age groups.
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An estimate of total body muscle mass with dual-energy X-ray absorptiometry (DXA; appendicular muscle mass divided by 0.75) was compared with 24-h urinary creatinine excretion in 59 healthy men and women [20-30 yr (younger), 45-59 yr (middle age), and 60-79 yr (older)] who stayed in a clinical research center for 5 days. Total body water ((2)H(2)O dilution), fat (underwater weighing), bone mineral (DXA), and total body protein mass (based on a 4-compartment model) were also measured. Muscle mass estimates by DXA and creatinine were highly correlated (r = 0.80). However, stepwise multiple regression indicated that a significant amount of additional between-subject variability in DXA-based muscle mass estimates could be explained by total body water. Creatinine excretion, knee extensor strength, and total body protein mass all decreased with age, suggesting a decline in muscle cell mass with aging. However, DXA-based muscle mass and measures of nonfat body mass (i.e., lean body mass by (2)H(2)O and fat-free body mass by underwater weighing) did not change with age. These results indicate that DXA and urinary creatinine excretion give different results regarding the decline in total body muscle mass with aging. The factor(s) responsible for the apparent underestimate of age-related sarcopenia by DXA remain to be fully defined, but changes in body water may be an important contributor. (+info)
Reliability and validity of body composition measures in female athletes.
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The purpose of this investigation was to determine the reliability and validity of bioelectrical impedance (BIA) and near-infrared interactance (NIR) for estimating body composition in female athletes. Dual-energy X-ray absorptiometry was used as the criterion measure for fat-free mass (FFM). Studies were performed in 132 athletes [age = 20.4 +/- 1.5 (SD) yr]. Intraclass reliabilities (repeat and single trial) were 0.987-0.997 for BIA (resistance and reactance) and 0.957-0.980 for NIR (optical densities). Validity of BIA and NIR was assessed by double cross-validation. Because correlations were high (r = 0.969-0.983) and prediction errors low, a single equation was developed by using all 132 subjects for both BIA and NIR. Also, an equation was developed for all subjects by using height and weight only. Results from dual-energy X-ray absorptiometry analysis showed FFM = 49.5 +/- 6.0 kg, which corresponded to %body fat (%BF) of 20.4 +/- 3.1%. BIA predicted FFM at 49.4 +/- 5.9 kg (r = 0.981, SEE = 1.1), and NIR prediction was 49. 5 +/- 5.8 kg (r = 0.975, SEE = 1.2). Height and weight alone predicted FFM at 49.4 +/- 5.7 kg (r = 0.961, SEE = 1.6). When converted to %BF, prediction errors were approximately 1.8% for BIA and NIR and 2.9% for height and weight. Results showed BIA and NIR to be extremely reliable and valid techniques for estimating body composition in college-age female athletes. (+info)