56,873 research outputs found

    Alkenylation and Allylation of Aldehydes by Using an Ni/Cr/TDAE Redox System

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    In 360 females, Bone mineral density (BMD) in lumbar vertebrae (L2-L4) was assessed by quantitative computed tomography (QCT), and the values obtained were compared with the frequency of vertebral transformation or fracture as assessed by lateral scan image (scanogram) by X-ray CT. A correlation was observed between the frequency of vertebral transformation (or fracture) and lumbar BMD values : BMD under 125 mg/cm(3) was observed over 90% of women with vertebral transformation, and BMD under 70mg/cm(3) was found about 50% of them. These results suggest that decrease in BMD in lumbar vertebrae leads to vertebral transformation or fracture. Thus, measurement of BMD by QCT would be very useful in predicting vertebral transformation or fractures

    Bone mineral density in patients with inherited bone marrow failure syndromes.

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    BackgroundPatients with inherited bone marrow failure syndromes (IBMFS) may have several risk factors for low bone mineral density (BMD). We aimed to evaluate the prevalence of low BMD in IBMFS and determine the associated risk factors.MethodsPatients with IBMFS with at least one dual-energy X-ray absorptiometry (DXA) scan were evaluated. Diagnosis of each IBMFS, Fanconi anemia (FA), dyskeratosis congenita, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome was confirmed by syndrome-specific tests. Data were gathered on age, height, and clinical history. DXA scans were completed at the lumbar spine, femoral neck, and forearm. BMD was adjusted for height (HAZ) in children (age ≤20 years). Low BMD was defined as a BMD Z-score and HAZ ≤-2 in adults and children, respectively, in addition to patients currently on bisphosphonate therapy.ResultsNine of thirty-five adults (26%) and eleven of forty children (27%) had low BMD. Adults with FA had significantly lower BMD Z-scores than those with other diagnoses; however, HAZ did not vary significantly in children by diagnosis. Risk factors included hypogonadism, iron overload, and glucocorticoid use.ConclusionsAdults and children with IBMFS have high prevalence of low BMD. Prompt recognition of risk factors and management are essential to optimize bone health

    Diet and bone mineral density study in postmenopausal women from the TwinsUK registry shows a negative association with a traditional English dietary pattern and a positive association with wine

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    Background: The effect of diet on bone mineral density (BMD) remains controversial, mainly because of difficulties in isolating dietary factors from the confounding influences of age, lifestyle, and genetic factors. Objective: The aim of this study was to use a novel method to examine the relation between BMD and diet. Design: A co-twin control study design with linear regression modeling was used to test for associations between BMD and habitual intakes of calcium, vitamin D, protein, and alcohol plus 5 previously identified dietary patterns in postmenopausal women from the TwinsUK registry. This approach exploited the unique matching of twins to provide an estimate of an association that was not confounded by age, genetic background, or shared lifestyle. Results: In >2000 postmenopausal women (BMD data on 1019, 1218, and 1232 twin pairs at the hip neck, hip, and spine, respectively), we observed a positive association between alcohol intake (from wine but not from beer or spirits) and spine BMD (P = 0.01) and a negative association with a traditional 20th-century English diet at the hip neck (P = 0.01). Both associations remained borderline significant after adjustment for mean twin-pair intakes (P = 0.04 and P = 0.055, respectively). Other dietary patterns and intakes of calcium, vitamin D, and protein were unrelated to BMD. Conclusion: Our results showed that diet has an independent but subtle effect on BMD; wine intake was positively associated with spine BMD, whereas a traditional (20th-century) English diet had a negative association with hip BMD

    Bone mineral density and risk of heart failure in older adults: The Cardiovascular Health Study

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    Background Despite increasing evidence of a common link between bone and heart health, the relationship between bone mineral density ( BMD ) and heart failure ( HF ) risk remains insufficiently studied. Methods and Results We investigated whether BMD measured by dual‐energy x‐ray absorptiometry was associated with incident HF in an older cohort. Cox models were stratified by sex and interactions of BMD with race assessed. BMD was examined at the total hip and femoral neck separately, both continuously and by World Health Organization categories. Of 1250 participants, 442 (55% women) developed HF during the median follow‐up of 10.5 years. In both black and nonblack women, neither total hip nor femoral neck BMD was significantly associated with HF ; there was no significant interaction by race. In black and nonblack men, total hip, but not femoral neck, BMD was significantly associated with HF , with evidence of an interaction by race. In nonblack men, lower total hip BMD was associated with higher HF risk (hazard ratio, 1.13 [95% CI, 1.01–1.26] per 0.1 g/cm 2 decrement), whereas in black men, lower total hip BMD was associated with lower HF risk (hazard ratio, 0.74 [95% CI, 0.59–0.94]). There were no black men with total hip osteoporosis. Among nonblack men, total hip osteoporosis was associated with higher HF risk (hazard ratio, 2.83 [95% CI, 1.39–5.74]) compared with normal BMD . Conclusions Among older adults, lower total hip BMD was associated with higher HF risk in nonblack men but lower risk in black men, with no evidence of an association in women. Further research is needed to replicate these findings and to study potential underlying pathways. </jats:sec

    Skin thickness as a predictor of bone mineral density

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    Background: Low bone mineral density (BMD) has been correlated with increased risk of fracture, which in turn causes significant morbidity, mortality, and health and social care costs. Currently, bone mineral density (BMD) is measured by dual energy X-ray absorptiometry (DXA) scanning, an expensive and time consuming technique that is not universally available. An alternative method of predicting BMD is therefore required, that can be used for wider screening purposes. As the connective tissue of both skin and bone contain > 70% collagen type I, skin thickness (ST) has previously been proposed to correlate with BMD. Objective: To assess the correlation between BMD and ST; and develop a model for the prediction of BMD that includes other factors, such as age, weight, height and menopausal status, which may influence this relationship. Methods: We analysed data collected from 1406 women (mean age of 55.2 years) at the Bone Density Clinic at St. Luke's Hospital. Their BMD was measured by DXA scanning at six sites: L2, L3, and L4 vertebrae; Ward's triangle, femoral neck and trochanter at the hip. Skin thickness (ST) was measured at the T1 dermatome using ultrasonography. Medical history (including drug and bone history) was also elicited. Statistical tests, in particular multivariate analysis of variance (MANOVA), were used to select significant predictors of bone mineral density. Results: Age, weight, and skin thickness were all shown to have a significant relationship with BMD in postmenopausal women (MANOVA p= 0.001 for weight, age and p< 0.05 for skin thickness). We show a significant relationship between height and BMD at the lumbar spine (MANOVA p< 0.03) but not at the hip. Age and weight variables are of particular importance in predicting BMD in this model, while ST is more important than height. Used in conjunction, weight, age, height and skin thickness result in the model having an R2 value of 0.3 at the femoral neck, and 0.25 at L3. In non-menopausal women, we show that only weight has a significant relationship with BMD (MANOVA P< 0.007), while age, height and skin thickness do not. Conclusions: In the postmenopausal woman, a combination of weight, height, age and skin thickness allows the prediction of 30% of the BMD at the femoral neck and 25% of the BMD at L3. Measuring these variables is simple and inexpensive, and would allow large scale screening programmes for people at risk, thus reducing morbidity, mortality and costs arising from fracture.peer-reviewe

    Bone mineral density and body composition in high-performing cricket players : an exploratory study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, at Massey University, Albany, New Zealand

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    Background/Aim: Cricket is a popular sport both in New Zealand, and internationally. Cricketers have a high prevalence of stress fractures, which may in part be linked to bone mineral density. However, little research exists investigating bone health in this group. The primary aim of this study was to investigate determinants of bone mineral density (BMD) in a group of highperforming cricketers. Secondary aims included measuring musculoskeletal differences in the dominant versus non-dominant arm, and monitoring pre and postseason body composition. Methods: Healthy male (n=27) and female (n=11) cricketers aged 16-33y were recruited. BMD was measured using DXA, and body composition was measured pre and post-season using bioelectrical impedance analysis (BIA). Food frequency questionnaires (FFQ’s) and a lifestyle & health questionnaire were completed. Determinants of BMD were tested using hierarchical multiple regression analysis. A dependent samples t-test was used to determine differences between dominant and non-dominant arms and changes in body composition over the season. Results: Skeletal muscle mass was a significant predictor of BMD and accounted for 31, 18, and 38 percent of BMD variation at the hip, spine, and total body, respectively. Age and calcium intake did not predict BMD at any site. BMD and lean mass were significantly greater (p<0.05) in the dominant arms of both males (+0.056g/cm2 and +308.4g) and females (+0.078g/cm2 and +254.2g). A 0.8kg reduction in post-season skeletal muscle mass was found in females (p<0.05), with no differences found in males. Conclusions: Skeletal muscle was the strongest predictor of BMD in this group, while age and calcium intake showed no effect. Significant differences in BMD and lean mass were observed between dominant and non-dominant arms. Skeletal muscle in males remained unchanged from beginning to end of season, and was reduced in females. Training methods in this group should target development and maintenance of muscle mass in order to optimise BMD

    The relationship between anthropometric parameters and bone mineral density in an Iranian referral population

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    Osteoporosis is a common health concern in both developed and developing countries. In this study the association between anthropometric measures and osteoporosis was investigated in 3630 males and females visiting BMD clinic of Shariati Hospital, Tehran, Iran, a teaching hospital and referral center for osteoporosis affiliated to the Tehran University of Medical Sciences. Anthropometric measurements obtained and also Bone Mineral Density (BMD) measurement was done using a Lunar DPXMD densitometer. Data were analyzed using SPSS with Chi-square and ANOVA with post-hoc tests. Results showed that the weight, BMI and age had the strongest correlation with the BMD values in the studied people. While age is negatively correlated with BMD in all the studied people, a positive association was noted between weight, height and BMI and BMD parameters (P&lt;0.01). It was concluded that certain anthropometric parameters (BMI and weight) can considerably affect one's risk of developing osteoporosis. Further research on the effect of these variables on the association of weight and BMD is needed

    A pilot investigation of load-carrying on the head and bone mineral density in premenopausal, black African women

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    Although the influence of weight bearing activity on bone mass has been widely investigated in white women, few studies have been conducted in black, African populations. We investigated bone mineral density (BMD) in black South African women, with and without a history of load-carrying on the head. We also investigated whether load carrying may offer protection against low BMD in users of injectable progestin contraception (IPC). Participants were 32 black, South African women (22.4±3.2 yrs). Load carrying history was determined by questionnaire and interview and participants were grouped as load carriers (LC; n=18) or non load carriers (NLC; n=14). Ten women were using IPC and 6 were load-carriers. Total body (TB), lumbar spine (LS) and total hip (H) BMD were measured by dual energy X-ray absorptiometry. There were no differences in BMD between LC and NLC, and after controlling for age and BMI using two-tailed partial correlations. IPC users had lower BMD at all sites compared to non IPC users (p&lt;0.05) and there were no associations between load carrying and BMD in this group. When IPC users were excluded from analysis, LC had higher LS BMD than NLC (p&lt;0.005). Correlations were found between the weight of load carried and LS BMD (r=0.743, p&lt;0.005), and between years of load carrying and LS and TB BMD (r=0.563, r=0.538 respectively; both p&lt;0.05). Load carrying on the head may offer osteogenic benefits to the spine but these benefits did not appear in women using IPC

    Measurement of bone quality in growing male rats using dual energy x-ray absorptiometry and bone ash content : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Animal Science at Massey University, Palmerston North, New Zealand

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    Growing male rats have been considered and used as a model for bone growth and prevention of osteoporosis because of their high bone turnover and demand for calcium. Dual Energy X-ray Absorptiometry (DEXA) is a useful tool for identifying minimal changes in bone mineral density and has recently been adapted for use in small animal models. The objective of this trial was to identify the changes in Bone Mineral Density (BMD) in relation to age and to identify how BMD varies from site to site. Sixty male Sprague-Dawley rats were split into six groups to allow measurements at one, two, three, four, five and six months of age (n=10 per group). At each time point a group of rats was scanned using a QDR4000 DEXA machine from Hologic. Duplicate BMD measurements were obtained for the whole body, spine and both femurs in vivo. The rats were then euthanased and the spine and both femurs were excised for ex vivo DEXA scanning and ashed calcium analysis. BMD increased almost linearly to four months and then formed a plateau. This indicates that from weaning to four months is an especially sensitive time for manipulating bone growth in male rats. There was a significant difference in BMD between groups (P<0.001), which is to be expected in growing rats. There was also a significant difference in BMD within groups (p<0.001), believed to be due to variation at two and five months of age. There was a very strong positive correlation between weight and BMD and age and BMD at all sites, indicating that BMD is a strongly related to both weight and age. All sites were strongly correlated to each other and to the ashed calcium values. The excised femur had a lower BMD value than the in vivo femur, although the two values were strongly correlated. This is believed to be due to differences in positioning and indicates that the two methods cannot be used interchangeably. These results indicate that bone mineral density is the gold standard for following changes in bone growth over time in the growing rat. Alternatively, ashed bone calcium content can be used, but only as a once off endpoint
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