Search

To determine the effects of high velocity resistance training (HVRT) on bone mineral density (BMD) in older adults. A systematic review was conducted using five databases. Records were screened by two independent reviewers. Inclusion criteria: adults ≥50 years old, HVRT defined as rapid concentric and slow eccentric phase against an external load, control group and/or other intervention group, BMD measured using dual X-ray absorptiometry, and ≥6 months. 25 studies met the inclusion criteria. 12 were original intervention studies (8 RCTs) with n = 1203 people. 13 papers were follow up studies of these original interventions. Heterogeneity of studies meant no meta-analysis was performed. Moderate evidence suggests a small statistically significant effect of HVRT on BMD in older adults at the lumbar spine, total hip, and femoral neck ranging from 0.9 % to 5.4 %. BMD measurements significantly decreased post-intervention in follow-up studies where the interventions had ceased. Dose-response of HVRT was shown to positively impact BMD when ≥2 sessions per week are completed. HVRT plays a role in increasing BMD of the lumbar spine, femoral neck, and total hip. Doses of higher intensity exercise performed ≥2 sessions per week will yield the most skeletal benefits, and if exercise is stopped for >6 months, benefits achieved may be lost. • High velocity resistance training (HVRT) is defined as rapid concentric and slow eccentric phase against an external load. • HVRT increases bone mineral density at the spine and hip in older adults. • Bone mineral density increased with ≥2 intervention sessions completed per week. • If exercise ceased for ≥6 months, skeletal benefits are lost. [ABSTRACT FROM AUTHOR]

As the successor of Dual Photon Absorptiometry (DPA), Dual X-ray Absorptiometry (DXA) has seen 30 years of continuous technological innovations. Implementation of measures for standardization and quality assurance made DXA a reliable and clinically useful approach. Its use in clinical multicenter drug studies in osteoporosis lead to general acceptance as the standard technique of bone densitometry. The limitations of DXA are well established. As a measure of areal bone mineral density (aBMD) it depends on bone size and is biased by overlaying soft tissue and calcified structures. To some extent these errors can be reduced by estimation of bone depth and/or lateral imaging. DXA based aBMD can be supplemented by additional information obtainable from DXA scans: geometric indices such as hip axis length or complex models like 2-D finite element analysis have been developed and tested. Given the drastic improvement in image quality current DXA scans can be used for Vertebral Fracture Analysis (VFA) or grading of Abdominal Aortic Calcifications. A textural measure, Trabecular Bone Score (TBS) provides independent information on fracture risk. DXA devices can also be used for assessments beyond bone density. Periprosthetic aBMD changes can be monitored to study the mechanical fitting of bone implants. Total body composition measurements are increasingly being used in studies on nutrition, obesity, and sarcopenia. 30 years after its inception DXA is the undisputed standard imaging technique for the assessment of osteoporotic fracture risk with new applications beyond bone densitometry adding to its value. [ABSTRACT FROM AUTHOR]

Prenatal alcohol exposure can contribute to long term adverse health outcomes. Development of the skeletal system begins at the early embryonic stage and continues into early adulthood but the effect of prenatal alcohol exposure on skeletal growth is relatively unexplored in a clinical population. Here, we performed dual X-ray absorptiometry to examine bone, fat, and muscle accrual in children and adolescents diagnosed with, or at risk of, fetal alcohol spectrum disorders (FASDs). Children (aged 4–9 years) with FASD or at risk of FASD (n = 10) had similar growth to age matched controls (n = 27). By adolescence (aged ≥10 years), those with FASDs (n = 13) were shorter and had lower areal bone mineral density and lean tissue mass than typically developing peers (n = 29). Overall, adolescents diagnosed with FASDs had greater odds of impairments to bone and body composition. These findings highlight the importance of early FASD diagnosis and appropriate post-diagnostic medical follow-up to enable timely, effective interventions to optimize bone and body composition during paediatric growth. [Display omitted] • Children with/at risk of FASDs had similar growth to control group. • Adolescents with FASDs had lower bone mineral density than the control group. • Findings highlight importance of early diagnosis of FASDs. [ABSTRACT FROM AUTHOR]

Abstract: Dual X-ray absorptiometry (DXA) is increasingly used to measure bone density in children. If the system software does not include pediatric scan modes, then child examinations must be performed using adult scan modes that give a higher radiation dose to children than adults. This report describes a study to compare the effective dose to children and adults from DXA scans performed on the Hologic Discovery and QDR4500 models. Depth dose measurements were made using thermoluminescent dosimeters in a Rando phantom and were mapped onto the Cristy mathematical phantoms representing a 5-, 10- and 15-year-old child and an adult, and effective dose (ED) was calculated using the ICRP Publication-60 tissue weighting factors. The ED for spine (hip) examinations performed with the Express mode using the default adult scan lengths were 16.1 (9.8), 11.1 (6.7), 5.6 (3.9) and 4.4 (3.1) μSv for a 5-, 10- and 15-year-old child and adult respectively. However, if care is taken to adjust scan lengths appropriately, the child doses were reduced to 9.1 (7.4), 7.1 (5.9) and 5.0 (3.7) μSv. ED figures for the Fast and Array modes were larger by factors of 1.5 and 3 respectively. EDs for whole body scans for a 5-, 10- and 15-year-old child and adult performed on the A-model (W-model) were 5.2 (10.5), 4.8 (9.6), 4.2 (8.4) and 4.2 (8.4) μSv. Using the infant whole body mode (only available on the A-model), they were 7.5 μSv for a 1-year-old and 8.9 μSv for a neonate. Although doses from child DXA examinations are low, it is still important to keep them as small as possible. DXA operators using Discovery systems can do this by using the Express scan mode, by setting appropriate values of the scan length before scan acquisition and by avoiding mistakes that lead to scans having to be unnecessarily repeated. [Copyright &y& Elsevier]

End-stage renal failure deteriorates bone mass and increases fracture risk. However, there are conflicting reports in the literature regarding the effects of mild to moderate renal dysfunction on bone mineral density (BMD). We investigated the association between renal function and BMD at the spine and hip and bone metabolism markers in community-dwelling elderly Japanese men. From 2174 male volunteers aged ≥65 years, we examined 1477 men after excluding those with diseases or medications known to affect bone metabolism. Renal function was assessed by serum cystatin C and estimated glomerular filtration rate (eGFR) calculated using the Modification of Diet in Renal Disease Study equation. Bone metabolism was evaluated using levels of serum amino-terminal propeptide of type I procollagen (PINP) and tartrate-resistant acid phosphatase isoenzyme 5b (TRACP-5b), which represent bone metabolic status independent of renal function. eGFR was inversely associated with BMD after adjusting for potential confounders (P < 0.01). Cystatin C showed a weaker but significant association with BMD. eGFR was modestly positively associated with PINP levels (P = 0.04), although cystatin C concentrations were neither associated with PINP nor TRACP-5b levels. Since BMD integrates bone metabolism from the past to present, inverse associations between renal function and BMD may be attributed to past factors, such as obesity. Our findings suggest that low renal function does not affect bone metabolism in a population of community-dwelling elderly Japanese men. Longitudinal studies will be necessary to clarify whether low renal function affects bone loss., (Copyright © 2013 Elsevier Inc. All rights reserved.)