ORCID Profile
0000-0002-0348-5643
Current Organisations
Australian Catholic University - Strathfield Campus
,
University of Calgary
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Publisher: Wiley
Date: 16-08-2019
DOI: 10.1111/COBI.13097
Abstract: Recent increases in ivory poaching have depressed African elephant populations. Successful enforcement has led to ivory stockpiling. Stockpile destruction is becoming increasingly popular, and most destruction has occurred in the last 5 years. Ivory destruction is intended to send a strong message against ivory consumption, both in promoting a taboo on ivory use and catalyzing policy change. However, there has been no effort to establish the distribution and extent of media reporting on ivory destruction events globally. We analyzed media coverage of the largest ivory destruction event in history (Kenya, 30 April 2016) across 11 nation states connected to ivory trade. We used an online-media crawling tool to search online media outlets and subjected 5 of the largest print newspapers (by circulation) in 5 nations of interest to content analysis. Most online news on the ivory burn came from the United States (81% of 1944 articles), whereas most of the print news articles came from Kenya (61% of 157 articles). Eighty-six to 97% of all online articles reported the burn as a positive conservation action, whereas 4-50% discussed ivory burning as having a negative impact on elephant conservation. Most articles discussed law enforcement and trade bans as effective for elephant conservation. There was more relative search interest globally in the 2016 Kenyan ivory burn than any other burn in 5 years. Ours is the first attempt to track the reach of media coverage relative to an ivory burn and provides a case study in tracking the effects of a conservation-marketing event.
Publisher: Springer Science and Business Media LLC
Date: 21-10-2010
DOI: 10.1007/S00774-010-0226-8
Abstract: Sports training characterized by impacts or weight-bearing activity is well known to induce osteogenic effects on the skeleton. Less is known about the potential effects on bone strength and geometry, especially in female adolescent athletes. The aim of this study was to investigate hip geometry in adolescent soccer players and swimmers compared to normal values that stemmed from a control group. This study included 26 swimmers (SWIM 15.9 ± 2 years) and 32 soccer players (SOC 16.2 ± 0.7 years), matched in body height and weight. A group of 15 age-matched controls served for the calculation of hip parameter Z-scores. Body composition and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA). DXA scans were analyzed at the femoral neck by the hip structure analysis (HSA) program to calculate the cross-sectional area (CSA), cortical dimensions (inner endocortical diameter, ED outer width and thickness, ACT), the centroid (CMP), cross-sectional moment of inertia (CSMI), section modulus (Z), and buckling ratio (BR) at the narrow neck (NN), intertrochanteric (IT), and femoral shaft (FS) sites. Specific BMDs were significantly higher in soccer players compared with swimmers. At all bone sites, every parameter reflecting strength (CSMI, Z, BR) favored soccer players. In contrast, swimmers had hip structural analysis (HSA) Z-scores below the normal values of the controls, thus denoting weaker bone in swimmers. In conclusion, this study suggests an influence of training practice not only on BMD values but also on bone geometry parameters. Sports with high impacts are likely to improve bone strength and bone geometry. Moreover, this study does not support the argument that female swimmers can be considered sedentary subjects regarding bone characteristics.
Publisher: Human Kinetics
Date: 11-2017
Abstract: Purpose: To synthesize existing literatures on the impact of gymnastics participation on the skeletal health of young male gymnasts. Methods: Following a systematic search, 12 studies were included in this review. Quality of included studies was assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE modified) criteria. Results: Assessment of skeletal health varied between and within imaging modality protocols. Gymnasts had higher total bone content, greater total and trabecular bone density, larger bone size, a thicker cortex, and higher estimates of bone strength than controls. Recreational studies reported no difference in height or weight between gymnasts and controls however, elite gymnasts were shorter and lighter than nongymnasts. STROBE scores ranged from 65% to 95%. Conclusion: Gymnastics participation may be beneficial to the bone health of young males as gymnasts had higher bone density and bone mineral content, larger bones, and greater estimates of bone strength than controls.
Publisher: Springer Science and Business Media LLC
Date: 08-01-2018
Publisher: Springer Science and Business Media LLC
Date: 08-04-2015
DOI: 10.1007/S00198-015-3110-5
Abstract: The relation between serum 25-hydroxy vitamin D [25(OH)D] and bone quality is not well understood, particularly for high levels. We measured bone microarchitecture in three groups of people stratified by their serum 25(OH)D. There was a weak association of serum 25(OH)D and microarchitecture for this cross-sectional population, suggesting possible benefits to bone quality. Vitamin D plays an important role in bone and mineral metabolism, but the relation between serum 25(OH)D and bone quality is not well understood. Here, we present a cross-sectional study that investigated a convenience group of participants from an ongoing health initiative in Alberta, Canada, who have been receiving daily vitamin D supplementation. A total of 105 participants were organized into three groups based on their serum 25(OH)D levels: low ( 175 nmol/L). They were also assessed with 25(OH)D as a continuous variable. Average daily supplementation was 7670 ± 438 IU, and the change in 25(OH)D ranged from 22 to 33 % during the period of receiving supplements. We used high-resolution peripheral quantitative computed tomography measurements at the radius and tibia to assess bone microarchitecture. Microarchitectural parameters were not strongly associated with serum 25(OH)D. In the tibia, there were fewer trabeculae (TbN p = 0.015) and a non-significant trend toward thicker trabeculae (p = 0.067) of the high group. Body mass index (BMI) was negatively associated with serum 25(OH)D levels (p < 0.001) and PTH levels (p < 0.001). There was no clinically significant relationship detected between high serum 25(OH)D and high serum calcium. These data suggest a weak relationship between serum 25(OH)D and bone microarchitecture in this population of mostly vitamin-D-sufficient participants, and there were no indications of negative effects related to the high supplementation levels. These data provided a basis to design and implement our 3-year dose-dependent randomized controlled trial investigating the effects of vitamin D supplementation on bone health outcomes.
Publisher: Springer Science and Business Media LLC
Date: 19-05-2020
Publisher: Elsevier BV
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 06-10-2015
DOI: 10.1007/S00223-015-0064-8
Abstract: Women with Turner syndrome (TS) are known to be at risk of osteoporosis. While childhood growth hormone (GH) treatment is common in TS, the impact of this therapy on bone health has been poorly understood. The objective of this study was to determine the influence of childhood GH treatment on adult bone quality in women with TS. 28 women aged 17-45 with confirmed TS (12 GH-treated) agreed to participate in this cross-sectional study. Dual X-ray absorptiometry (DXA) of lumbar spine, hip, and radius and high-resolution peripheral quantitative computed tomography (HR-pQCT) scans of the radius and tibia were used to determine standard morphological and micro-architectural parameters of bone health. Finite element (FE) analysis and polar moment of inertia (pMOI) were used to estimate bone strength. GH-treated subjects were +7.4 cm taller (95% CI 2.5-12.3 cm, p = 0.005). DXA-determined areal BMD of hip, spine, and radius was similar between treatment groups. Both tibial and radial total bone areas were greater among GH-treated subjects (+20.4 and +21.2% respectively, p < 0.05), while other micro-architectural results were not different between groups. pMOI was significantly greater among GH-treated subjects (radius +35.0%, tibia +34.0%, p < 0.05). Childhood GH treatment compared to no treatment in TS was associated with an increased height, larger bones, and greater pMOI, while no significant difference in DXA-derived BMD, HR-pQCT micro-architectural parameters, or FE-estimated bone strength was detected. The higher pMOI and greater bone size may confer benefit for fracture reduction in these GH-treated patients.
Publisher: Wiley
Date: 03-05-2023
DOI: 10.1002/JBMR.4808
Abstract: Most fracture risk assessment tools use clinical risk factors combined with bone mineral density (BMD) to improve assessment of osteoporosis however, stratifying fracture risk remains challenging. This study developed a fracture risk assessment tool that uses information about volumetric bone density and three‐dimensional structure, obtained using high‐resolution peripheral quantitative compute tomography (HR‐pQCT), to provide an alternative approach for patient‐specific assessment of fracture risk. Using an international prospective cohort of older adults ( n = 6802) we developed a tool to predict osteoporotic fracture risk, called μFRAC. The model was constructed using random survival forests, and input predictors included HR‐pQCT parameters summarizing BMD and microarchitecture alongside clinical risk factors (sex, age, height, weight, and prior adulthood fracture) and femoral neck areal BMD (FN aBMD). The performance of μFRAC was compared to the Fracture Risk Assessment Tool (FRAX) and a reference model built using FN aBMD and clinical covariates. μFRAC was predictive of osteoporotic fracture (c‐index = 0.673, p 0.001), modestly outperforming FRAX and FN aBMD models (c‐index = 0.617 and 0.636, respectively). Removal of FN aBMD and all clinical risk factors, except age, from μFRAC did not significantly impact its performance when estimating 5‐year and 10‐year fracture risk. The performance of μFRAC improved when only major osteoporotic fractures were considered (c‐index = 0.733, p 0.001). We developed a personalized fracture risk assessment tool based on HR‐pQCT that may provide an alternative approach to current clinical methods by leveraging direct measures of bone density and structure. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
Publisher: Wiley
Date: 03-02-2021
DOI: 10.1002/JBMR.4247
Publisher: Springer Science and Business Media LLC
Date: 29-11-2019
DOI: 10.1007/S00198-019-05214-0
Abstract: Manual correction of automatically generated contours for high-resolution peripheral quantitative computed tomography can be time consuming and introduces precision error. However, bias related to the automated protocol is unknown. This study provides insight into error bias that is present when using uncorrected contours and inter-operator precision error based on operator training. High-resolution peripheral quantitative computed tomography workflow includes manually correcting contours generated by the manufacturer's automated protocol. There is interest in minimizing corrections to save time and reduce precision error however, bias related to the automated protocol is unknown. This study quantifies error bias when contours are uncorrected and identifies the impact of operator training on bias and precision error. Forty-five radii and tibiae scans across a representative range of bone density were analyzed using the automated and manually corrected contours of three operators, with training ranging from beginner to expert, and compared with a "ground truth" to estimate bias. Inter-operator precision was measured across operators. The tibia had greater error bias than the radius when contours were uncorrected, with compartmental bone mineral densities and cortical microarchitecture having greatest biases, which could have significant implications for interpretation of studies using this skeletal site. Bias and precision error were greatest when contours were corrected by the beginner operator however, when this operator was removed, bias was no longer present and inter-operator precision was between 0.01 and 3.74% for all parameters except cortical porosity. These findings establish the need for manual correction and provide guidance on operator training needed to maximize workflow efficiency.
Publisher: Springer Science and Business Media LLC
Date: 30-11-2020
DOI: 10.1007/S00223-019-00638-6
Abstract: This study aimed to evaluate associations of parity and breastfeeding history with postmenopausal bone loss. Early postmenopausal women from the Canadian Multicentre Osteoporosis Study were ided into three groups based on their reproductive histories: nulliparous (NP, n = 10), parous with 6 months breastfeeding (P-BF, n = 21). Women underwent dual X-ray absorptiometry and high-resolution peripheral quantitative computed tomography imaging at baseline and after 6 years to evaluate bone mineral density (BMD), bone microstructure, and finite element-estimated failure load. Average age at baseline was 57 years. Baseline density, microstructure, and failure load were not different among groups. In all women, total and cortical BMD decreased significantly at the tibia and radius. P-BF women only experienced a significant decline in tibial trabecular BMD, with a greater magnitude of change for P-BF than NP women (p = 0.002). Overall, results suggest that early postmenopausal bone health did not differ based on parity or breastfeeding history. Over the 6-year follow-up period, postmenopausal bone loss was evident in all women, with subtle differences in the rate of postmenopausal change among women with varying breastfeeding histories. Parous women who had breastfed for at least 6 months showed an elevated rate of trabecular BMD loss at the tibia. Meanwhile, correlation analyses suggest that longer durations of breastfeeding may be associated with reduced cortical bone loss at the radius. The lack of differences among groups in FE-derived failure load suggests that parity and breastfeeding history is unlikely to significantly affect postmenopausal risk of fracture.
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 2019
Publisher: The Endocrine Society
Date: 20-11-2019
Abstract: More than 3% of adults report vitamin D intakes of 4000 IU/day or more, but the safety of this practice is unknown. The objective of this work is to establish whether vitamin D doses up to 10 000 IU/day are safe and well tolerated. The Calgary Vitamin D Study was a 3-year, double-blind, randomized controlled trial. A single-center study was conducted at the University of Calgary, Canada. Participants included healthy adults (n = 373) ages 55 to 70 years with serum 25-hydroxyvitamin D 30 to 125 nmol/L. Participants were randomly assigned 1:1:1 to vitamin D3 400, 4000, or 10 000 IU/day. Calcium supplementation was initiated if dietary calcium intake was less than 1200 mg/day. In these prespecified secondary analyses, changes in serum 25-hydroxyvitamin D, calcium, creatinine, 24-hour urine calcium excretion, and incidence of adverse events were assessed. Between-group differences in adverse events were examined using incident rate differences and logistic regression. Of 373 participants (400: 124, 4000: 125, 10 000: 124), 49% were male, mean (SD) age was 64 (4) years, and 25-hydroxyvitamin D 78.0 (19.5) nmol/L. Serum calcium, creatinine, and 24-hour urine calcium excretion did not differ between treatments. Mild hypercalcemia (2.56-2.64 mmol/L) occurred in 15 (4%) participants (400: 0%, 4000: 3%, 10 000: 9%, P = .002) all cases resolved on repeat testing. Hypercalciuria occurred in 87 (23%) participants (400: 17%, 4000: 22%, 10 000: 31%, P = .01). Clinical adverse events were experienced by 365 (97.9%) participants and were balanced across treatment arms. The safety profile of vitamin D supplementation is similar for doses of 400, 4000, and 10 000 IU/day. Hypercalciuria was common and occurred more frequently with higher doses. Hypercalcemia occurred more frequently with higher doses but was rare, mild, and transient.
Publisher: Springer Science and Business Media LLC
Date: 15-06-2020
Publisher: Elsevier BV
Date: 11-2012
Publisher: Wiley
Date: 16-09-2020
DOI: 10.1002/JBMR.4152
Publisher: Cold Spring Harbor Laboratory
Date: 09-04-2013
Abstract: Nearly three-quarters of the 143 genetic signals associated with platelet and erythrocyte phenotypes identified by meta-analyses of genome-wide association (GWA) studies are located at non-protein-coding regions. Here, we assessed the role of candidate regulatory variants associated with cell type–restricted, closely related hematological quantitative traits in biologically relevant hematopoietic cell types. We used formaldehyde-assisted isolation of regulatory elements followed by next-generation sequencing (FAIRE-seq) to map regions of open chromatin in three primary human blood cells of the myeloid lineage. In the precursors of platelets and erythrocytes, as well as in monocytes, we found that open chromatin signatures reflect the corresponding hematopoietic lineages of the studied cell types and associate with the cell type–specific gene expression patterns. Dependent on their signal strength, open chromatin regions showed correlation with promoter and enhancer histone marks, distance to the transcription start site, and ontology classes of nearby genes. Cell type–restricted regions of open chromatin were enriched in sequence variants associated with hematological indices. The majority (63.6%) of such candidate functional variants at platelet quantitative trait loci (QTLs) coincided with binding sites of five transcription factors key in regulating megakaryopoiesis. We experimentally tested 13 candidate regulatory variants at 10 platelet QTLs and found that 10 (76.9%) affected protein binding, suggesting that this is a frequent mechanism by which regulatory variants influence quantitative trait levels. Our findings demonstrate that combining large-scale GWA data with open chromatin profiles of relevant cell types can be a powerful means of dissecting the genetic architecture of closely related quantitative traits.
Publisher: Wiley
Date: 22-11-2019
DOI: 10.1111/COBI.13220
Abstract: Although evidence-based approaches have become commonplace for determining the success of conservation measures for the management of threatened taxa, there are no standard metrics for assessing progress in research or management. We developed 5 metrics to meet this need for threatened taxa and to quantify the need for further action and effective alleviation of threats. These metrics (research need, research achievement, management need, management achievement, and percent threat reduction) can be aggregated to examine trends for an in idual taxon or for threats across multiple taxa. We tested the utility of these metrics by applying them to Australian threatened birds, which appears to be the first time that progress in research and management of threats has been assessed for all threatened taxa in a faunal group at a continental scale. Some research has been conducted on nearly three-quarters of known threats to taxa, and there is a clear understanding of how to alleviate nearly half of the threats with the highest impact. Some management has been attempted on nearly half the threats. Management outcomes ranged from successful trials to complete mitigation of the threat, including for one-third of high-impact threats. Progress in both research and management tended to be greater for taxa that were monitored or occurred on oceanic islands. Predation by cats had the highest potential threat score. However, there has been some success reducing the impact of cat predation, so climate change (particularly drought), now poses the greatest threat to Australian threatened birds. Our results demonstrate the potential for the proposed metrics to encapsulate the major trends in research and management of both threats and threatened taxa and provide a basis for international comparisons of evidence-based conservation science.
Publisher: Elsevier BV
Date: 03-2012
Publisher: Wiley
Date: 23-10-2020
DOI: 10.1002/JBMR.4190
Publisher: Human Kinetics
Date: 06-2009
Abstract: The aim of this study was to compare daily hydration profiles of competitive adolescent swimmers and less active maturation- and sex-matched controls. Hydration profiles of 35 competitive adolescent swimmers (male n = 18, female n = 17) and 41 controls (male n = 29, female n = 12) were monitored on 4 consecutive days. First morning hydration status was determined independently by urine specific gravity (USG) and urine color. Changes in fluid balance were estimated during the school day and in training sessions after adjusting for self-reported urine losses and fluid intake. Urinalyses revealed consistent fluid deficits (USG .020, urine color ≥5) independent of activity group, sex, and day of testing (hypohydration in 73–85% of s les, p .05). Fluid balance and intake were observed over typical school days in males and females from the 2 groups. During training, male swimmers lost more fluid relative to initial body mass but drank no more than females. Although both activity groups began each testing day with a similar hydration status, training induced significant variations in fluid balance in the swimmers compared with controls. Despite minimal fluid losses during in idual training sessions ( % body mass), these deficits significantly increased fluid needs for young swimmers over the school day.
Publisher: Wiley
Date: 24-01-2018
DOI: 10.1002/JBMR.3347
Abstract: The aim of this prospective study was to use high-resolution peripheral quantitative computed tomography (HR-pQCT) to determine if baseline skeletal parameters can predict incident fragility fracture in women and, secondly, to establish if women that fracture lose bone at a faster rate than those who do not fracture. Women older than 60 years who experienced a fragility fracture during the 5-year follow-up period (incident fracture group, n = 22) were compared with those who did not experience a fragility fracture during the study (n = 127). After image registration between baseline and follow-up measures, standard and cortical morphological analyses were conducted. Odds ratios were calculated for baseline values and annualized percent change of HR-pQCT and finite element variables. At the radius, baseline HR-pQCT results show women who fractured had lower total bone mineral density (Tt.BMD 19%), trabecular bone mineral density (Tb.BMD 25%), and trabecular number (Tb.N 14%), with higher trabecular separation (Tb.Sp 19%) than women who did not fracture. At the tibia, women with incident fracture had lower Tt.BMD (15%), Tb.BMD (12%), cortical thickness (Ct.Th 14%), cortical area (Ct.Ar 12%), and failure load (10%) with higher total area (Tt.Ar 7%) and trabecular area (Tb.Ar 10%) than women who did not fracture. Odds ratios (ORs) at the radius revealed every SD decrease of Tt.BMD (OR = 2.1), Tb.BMD (OR = 2.0), and Tb.N (OR = 1.7) was associated with a significantly increased likelihood of fragility fracture. At the tibia, every SD decrease in Tt.BMD (OR = 2.1), Tb.BMD (OR = 1.7), Ct.Th (OR = 2.2), Ct.Ar (OR = 1.9), and failure load (OR = 1.7) were associated with a significantly increased likelihood of fragility fracture. Irrespective of scanning modality, the annualized percent rate of bone loss was not different between fracture groups. The results suggest baseline bone density, microarchitecture, and strength rather than change in these variables are associated with incident fragility fractures in women older than 60 years. Furthermore, irrespective of fragility fracture status, women experienced changes in skeletal health at a similar rate. © 2017 American Society for Bone and Mineral Research.
Publisher: Springer Science and Business Media LLC
Date: 10-06-2012
DOI: 10.1007/S00198-011-1677-Z
Abstract: Recent reports indicate an increase in forearm fractures in children. Bone geometric properties are an important determinant of bone strength and therefore fracture risk. Participation in non-elite gymnastics appears to contribute to improving young girls' musculoskeletal health, more specifically in the upper body. The primary aim of this study was to determine the association between non-elite gymnastics participation and upper limb bone mass, geometry, and strength in addition to muscle size and function in young girls. Eighty-eight pre- and early pubertal girls (30 high-training gymnasts [HGYM, 6-16 hr/ wk], 29 low-training gymnasts [LGYM, 1-5 h r/wk] and 29 non-gymnasts [NONGYM]), aged 6-11 years were recruited. Upper limb lean mass, BMD and BMC were derived from a whole body DXA scan. Forearm volumetric BMD, bone geometry, estimated strength, and muscle CSA were determined using peripheral QCT. Upper body muscle function was investigated with muscle strength, explosive power, and muscle endurance tasks. HGYM showed greater forearm bone strength compared with NGYM, as well as greater arm lean mass, BMC, and muscle function (+5% to +103%, p < 0.05). LGYM displayed greater arm lean mass, BMC, muscle power, and endurance than NGYM (+4% to +46%, p < 0.05) however, the difference in bone strength did not reach significance. Estimated fracture risk at the distal radius, which accounted for body weight, was lower in both groups of gymnasts. Compared with NONGYM, HGYM tended to show larger skeletal differences than LGYM yet, the two groups of gymnasts only differed for arm lean mass and muscle CSA. Non-elite gymnastics participation was associated with musculoskeletal benefits in upper limb bone geometry, strength and muscle function. Differences between the two gymnastic groups emerged for arm lean mass and muscle CSA, but not for bone strength.
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.CCT.2018.02.009
Abstract: The optimum dose of vitamin D and corresponding serum 25-hydroxyvitamin D (25OHD) concentration for bone health is still debated and some health practitioners are recommending doses well above the Canada/USA recommended Dietary Reference Intake (DRI). We designed a three-year randomized double-blind clinical trial investigating whether there are dose-dependent effects of vitamin D supplementation above the Dietary Reference Intake (DRI) on bone health. The primary aims of this study are to assess, whether supplementation of vitamin D
Publisher: Springer Science and Business Media LLC
Date: 10-01-2017
DOI: 10.1007/S00198-016-3900-4
Abstract: The rate of change in bone density was not different between peri- and post-menopausal women. Differences in rate of change were observed in bone microarchitecture, specifically cortical porosity (Ct.Po), where peri-menopausal women increased +9% per year compared with the +6% per year for post-menopausal women. The purpose of this study was to compare changes in bone density and microarchitecture in peri- and post-menopausal women over 6 years. Peri- (n = 26) and post- (n = 65) menopausal women were selected from the Canadian Multicenter Osteoporosis Study. Caucasian women were scanned on dual x-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline and follow-up, an average 6 years later. To compare repeat scans, automated 3D image registration was conducted. At the radius and tibia, total volumetric BMD (Tt.BMD), total bone area (Tt.Ar) and cortical porosity (Ct.Po) were assessed, and finite element analysis estimated apparent bone strength. At the tibia, the rate of change for Ct.Po and Tt.Ar was different between groups. Peri-menopausal women had a + 9% per year increase in Ct.Po, but this increase was slower for post-menopausal women at +6% per year (p = 0.049). In addition, post-menopausal women had an increase in Tt.Ar of +0.13% per year compared with a slower increase of +0.06% per year for peri-menopausal women (p = 0.017). The rate of change of density between groups was not significantly different and was approximately -1% per year at the hip by DXA, and -1% per year at the radius and -0.5% per year tibia by HR-pQCT. This is a 6-year prospective HR-pQCT study exploring rate of change in Caucasian peri- and post-menopausal women. The microarchitectural features represented by Ct.Po and Tt.Ar changed at a significantly different rate between groups, but group differences were not detected by density measures.
Publisher: Routledge
Date: 11-09-2008
Publisher: Wiley
Date: 20-07-2020
DOI: 10.1002/JBMR.4114
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-03-2017
Publisher: Springer Science and Business Media LLC
Date: 14-08-2023
Publisher: Oxford University Press (OUP)
Date: 17-01-2018
Publisher: Wiley
Date: 17-07-2023
DOI: 10.1002/JBMR.4876
Abstract: In a 36‐month randomized controlled trial examining the effect of high‐dose vitamin D 3 on radial and tibial total bone mineral density (TtBMD), measured by high‐resolution peripheral quantitative tomography (HR‐pQCT), participants (311 healthy males and females aged 55–70 years with dual‐energy X‐ray absorptiometry T‐scores −2.5 without vitamin D deficiency) were randomized to receive 400 IU ( N = 109), 4000 IU ( N = 100), or 10,000 IU ( N = 102) daily. Participants had HR‐pQCT radius and tibia scans and blood s ling at baseline, 6, 12, 24, and 36 months. This secondary analysis examined the effect of vitamin D dose on plasma measurements of the vitamin D metabolome by liquid chromatography–tandem mass spectrometry (LC‐MS/MS), exploring whether the observed decline in TtBMD was associated with changes in four key metabolites [25‐(OH)D 3 24,25‐(OH) 2 D 3 1,25‐(OH) 2 D 3 and 1,24,25‐(OH) 3 D 3 ]. The relationship between peak values in vitamin D metabolites and changes in TtBMD over 36 months was assessed using linear regression, controlling for sex. Increasing vitamin D dose was associated with a marked increase in 25‐(OH)D 3 , 24,25‐(OH) 2 D 3 and 1,24,25‐(OH) 3 D 3 , but no dose‐related change in plasma 1,25‐(OH) 2 D 3 was observed. There was a significant negative slope for radius TtBMD and 1,24,25‐(OH) 3 D 3 (−0.05, 95% confidence interval [CI] −0.08, −0.03, p 0.001) after controlling for sex. A significant interaction between TtBMD and sex was seen for 25‐(OH)D 3 (female: −0.01, 95% CI −0.12, −0.07 male: −0.04, 95% CI −0.06, −0.01, p = 0.001) and 24,25‐(OH) 2 D 3 (female: −0.75, 95% CI −0.98, −0.52 male: −0.35, 95% CI −0.59, −0.11, p 0.001). For the tibia there was a significant negative slope for 25‐(OH)D 3 (−0.03, 95% CI −0.05, −0.01, p 0.001), 24,25‐(OH) 2 D 3 (−0.30, 95% CI −0.44, −0.16, p 0.001), and 1,24,25‐(OH) 3 D 3 (−0.03, 95% CI −0.05, −0.01, p = 0.01) after controlling for sex. These results suggest vitamin D metabolites other than 1,25‐(OH) 2 D 3 may be responsible for the bone loss seen in the Calgary Vitamin D Study. Although plasma 1,25‐(OH) 2 D 3 did not change with vitamin D dose, it is possible rapid catabolism to 1,24,25‐(OH) 3 D 3 prevented the detection of a dose‐related rise in plasma 1,25‐(OH) 2 D 3 . © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
Publisher: Springer Science and Business Media LLC
Date: 14-10-2020
Publisher: MDPI AG
Date: 19-02-2020
DOI: 10.3390/NU12020527
Abstract: Vitamin D supplementation is proposed as a fall prevention strategy, as it may improve neuromuscular function. We examined whether three years of vitamin D supplementation (400, 4000 or 10,000 IU daily) affects postural sway in older adults. Three hundred and seventy-three non-osteoporotic, vitamin D-sufficient, community-dwelling healthy adults, aged 55–70 years, were randomized to 400 (n = 124), 4000 (n = 125) or 10,000 (n = 124) IU daily vitamin D3 for three years. Sway index was assessed at baseline, 12-, 24- and 36-months using the Biosway machine. We tested participants under four conditions: eyes open or eyes closed with firm (EOFI, ECFI) or foam (EOFO, ECFO) surfaces. Secondary assessments examined sway in the anterior-posterior (AP) and medio-lateral (ML) directions. Linear mixed effects models compared sway between supplementation groups across time. Postural sway under EOFO and ECFO conditions significantly improved in all supplementation groups over time. Postural sway did not differ between supplementation groups at any time under any testing conditions in normal, AP or ML directions (p 0.05 for all). Our findings suggest that high dose (4000 or 10,000 IU) vitamin D supplementation neither benefit nor impair balance compared with 400 IU daily in non-osteoporotic, vitamin D-sufficient, healthy older adults.
Publisher: Informa UK Limited
Date: 07-02-2018
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/PC18024
Abstract: Since European occupation of Australia, human activities have caused the dramatic decline and sometimes extinction of many of the continent’s unique species. Here we provide a comprehensive review of threats to species listed as threatened under Australia’s Environment Protection and Bio ersity Conservation Act 1999. Following accepted global categories of threat, we find that invasive species affect the largest number of listed species (1257 species, or 82% of all threatened species) ecosystem modifications (e.g. fire) (74% of listed species) and agricultural activity (57%) are also important. The ranking of threats was largely consistent across taxonomic groups and the degree of species’ endangerment. These results were significantly different (P& .01) from recent analyses of threats to threatened species globally, which highlighted overexploitation, agriculture and urban development as major causes of decline. Australia is distinct not only in the bio ersity it contains but also in the extent and mixture of processes that threaten the survival of these species. Notably, the IUCN threat classification scheme separates the numerous threats (e.g. urban development, agriculture, mining) that cause habitat loss, fragmentation and degradation, hence further research is required to quantify the net impact of these types of habitat change. We provide feasible suggestions for a more coordinated national approach to threatened species conservation, which could provide decision makers and managers at all levels with improved resources and information on threats and management. Adequate policy, legislative support and funding are critical for ensuring that on-ground management is successful in halting the decline of Australia’s threatened species.
Publisher: Elsevier BV
Date: 08-2013
Publisher: Public Library of Science (PLoS)
Date: 06-06-2013
Publisher: Springer International Publishing
Date: 2019
Publisher: American Medical Association (AMA)
Date: 07-01-2020
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 12-08-2012
DOI: 10.1038/NG.2385
Publisher: Wiley
Date: 22-08-2022
DOI: 10.1002/JBMR.4663
Abstract: Femoral neck areal bone mineral density (FN aBMD) is a key determinant of fracture risk in older adults however, the majority of in iduals who have a hip fracture are not considered osteoporotic according to their FN aBMD. This study uses novel tools to investigate the characteristics of bone microarchitecture that underpin bone fragility. Recent hip fracture patients ( n = 108, 77% female) were compared with sex‐ and age‐matched controls ( n = 216) using high‐resolution peripheral quantitative computed tomography (HR‐pQCT) imaging of the distal radius and tibia. Standard morphological analysis of bone microarchitecture, micro‐finite element analysis, and recently developed techniques to identify void spaces in bone microarchitecture were performed to evaluate differences between hip fracture patients and controls. In addition, a new approach for phenotyping bone microarchitecture was implemented to evaluate whether hip fractures in males and females occur more often in certain bone phenotypes. Overall, hip fracture patients had notable deterioration of bone microarchitecture and reduced bone mineral density compared with controls, especially at weight‐bearing sites (tibia and femoral neck). Hip fracture patients were more likely to have void spaces present at either site and had void spaces that were two to four times larger on average when compared with non‐fractured controls ( p 0.01). Finally, bone phenotyping revealed that hip fractures were significantly associated with the low density phenotype ( p 0.01), with the majority of patients classified in this phenotype (69%). However, female and male hip fracture populations were distributed differently across the bone phenotype continuum. These findings highlight how HR‐pQCT can provide insight into the underlying mechanisms of bone fragility by using information about bone phenotypes and identification of microarchitectural defects (void spaces). The added information suggests that HR‐pQCT can have a beneficial role in assessing the severity of structural deterioration in bone that is associated with osteoporotic hip fractures. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
Publisher: Elsevier BV
Date: 09-2018
Publisher: Springer Science and Business Media LLC
Date: 23-12-2012
DOI: 10.1038/NG.2500
Publisher: American Medical Association (AMA)
Date: 27-08-2019
Publisher: Springer Science and Business Media LLC
Date: 07-04-2013
DOI: 10.1038/NG.2606
Publisher: Wiley
Date: 03-02-2021
DOI: 10.1002/JBMR.4251
Publisher: Wiley
Date: 14-01-2022
DOI: 10.1002/JBMR.4494
Abstract: Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most in iduals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one‐size‐fits‐all” approach to diagnosis and management of osteoporosis may not be suitable. High‐resolution peripheral quantitative computed tomography (HR‐pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR‐pQCT data from a multinational cohort ( n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c‐means clustering, an unsupervised machine‐learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR‐pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture ( p 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR).
Publisher: Springer Science and Business Media LLC
Date: 18-06-2018
Publisher: Springer Science and Business Media LLC
Date: 27-05-2014
DOI: 10.1007/S11657-014-0183-2
Abstract: Within a normative youth cohort (16-29 years) bone parameters for males and females remained stable at the radius. At the tibia, a peak was observed for females at 16-19 years, with bone density and strength decreasing by 29 years. To determine if bone microstructural and strength parameters identified by high-resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA) at the distal radius and tibia, peak within the age range of this youth cohort, and whether the timing of the peaks differ based on sex or skeletal site. We recruited 251 participants (158 female 16 to 29 years), grouping them into 5-year age brackets (16-19 20-24 25-29 years) assessing microstructural and strength parameters with HR-pQCT and FEA. HR-pQCT assessment of males and females (age-matched groups) showed males had higher total area and BMD, trabecular BMD and trabecular number (radius only) cortical thickness and porosity, and failure load, but lower cortical BMD (p < 0.05). Within sex, microstructural and strength parameters remained stable for males, but in females they appeared to peak at 16-19 years at the tibia. Tibia bone strength and trabecular BMD were highest in females 16-19 years (p < 0.05), and tibia cortical porosity was lowest in females 16-19 years (p < 0.001). With the exception of an age-related increase in cortical BMD, all other parameters were stable between 16 and 29 years at the radius for both males and females. We found no peak values for males or females at the radius. At the tibia, a peak was observed for females 16-19 years. These data provide a population-based assessment of bone microstructural and strength parameters from HR-pQCT and FEA in a youth cohort, showing clear differences in bone quality dependent on sex and skeletal site.
Publisher: Wiley
Date: 03-04-2017
DOI: 10.1002/JBMR.3129
Abstract: Longitudinal studies assessing age-related changes using high-resolution peripheral quantitative computed tomography (HR-pQCT) provide novel insight compared with cross-sectional analyses. The purpose of this cohort study was 1) to determine in iduals' change in HR-pQCT parameters over 5 years relative to least significant change (LSC), and 2) to evaluate if predicted rate of change from cross-sectional data is comparable to actual change from longitudinal investigation. A cohort of 466 (162 male, 304 female) participants completed two HR-pQCT scans with 5 years between assessments. After image registration, standard and cortical morphological analyses were conducted. Rate of bone microarchitectural change was compared between cross-sectional models and actual change calculated from longitudinal analyses. At the young end of the life span, we observed gains in total bone density of +0.2% to +2.9% per year, whereas the older participants (aged >50 years) lost total bone density at a rate of -0.3% to -1.3% per year. Declines in total bone density begin at age 40 years in females and 60 years in males, and significant adaptation was found at both ends of the age spectrum with respect to the LSC. Models predicting rate of change from cross-sectional data were similar to the actual change reported in this longitudinal study for total density and cortical thickness at the radius and cortical density at the tibia, but we found that changes in comparison to our 5-year longitudinal results were often overestimated from cross-sectional data. Studies aimed at observing age-related changes in a normative cohort, especially in a follow-up period of less than 5 years, are better to focus on the tibia rather than the radius because of the increased sensitivity to change at the tibia. © 2017 American Society for Bone and Mineral Research.
Publisher: Wiley
Date: 05-04-2017
DOI: 10.1002/JBMR.3128
Abstract: Second-generation high-resolution peripheral quantitative computed tomography (HR-pQCT) provides the highest resolution in vivo to assess bone density and microarchitecture in 3D. Although strong agreement of most outcomes measured with first- (XCTI) and second- (XCTII) generation HR-pQCT has been demonstrated, the ability to use the two systems interchangeably is unknown. From in vivo measurements, we determined the limits of estimating XCTII data from XCTI scans conducted in vivo and whether that estimation can be improved by linear cross-calibration equations. These data are crucial as the research field transitions to the new technology. Our study design established cross-calibration equations by scanning 62 in iduals on both systems on the same day and then tested those cross-calibrations on the same cohort 6 months later so that estimated (denoted as XCTII*) and "true" XCTII parameters could be compared. We calculated the generalized least-significant change (GLSC) for those predictions. There was strong agreement between both systems for density (R
Publisher: Wiley
Date: 09-06-2016
DOI: 10.1002/JBMR.2873
Abstract: The purpose of this study was to develop age-, site-, and sex-specific centile curves for common high-resolution peripheral quantitative computed tomography (HR-pQCT) and finite-element (FE) parameters for males and females older than 16 years. Participants (n = 866) from the Calgary cohort of the Canadian Multicentre Osteoporosis Study (CaMos) between the ages of 16 and 98 years were included in this study. Participants' nondominant radius and left tibia were scanned using HR-pQCT. Standard and automated segmentation methods were performed and FE analysis estimated apparent bone strength. Centile curves were generated for males and females at the tibia and radius using the generalized additive models for location, scale, and shape (GAMLSS) package in R. After GAMLSS analysis, age-, sex-, and site-specific centiles (10th, 25th, 50th, 75th, 90th) for total bone mineral density and trabecular number as well as failure load have been calculated. Clinicians and researchers can use these reference curves as a tool to assess bone health and changes in bone quality. © 2016 American Society for Bone and Mineral Research.
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.JSAMS.2012.07.006
Abstract: Participation in gymnastics prior to puberty offers an intriguing and unique model, particularly in girls. The in iduality comes from both upper and lower limbs being exposed to high mechanical loading through year long intensive training programs, initiated at a young age. Studying this unique model and the associated changes in musculoskeletal health during growth is an area of specific interest. Previous reviews on gymnastics participation and bone health have been broad and not limited to a particular maturation period, such as pre-puberty. To determine the difference in skeletal health between pre-pubertal girls participating in gymnastics compared with non-gymnasts. Meta-analysis. Following a systematic search, 17 studies were included in this meta-analysis. All studies used dual-energy X-ray absorptiometry to assess bone mineral density and bone mineral content. In addition, two studies included peripheral quantitative computed tomography. Following the implementation of a random effects model, gymnasts were found to have greater bone properties than non-gymnasts. The largest difference in bone health between gymnasts and non-gymnasts was observed in peripheral quantitative computed tomography-derived volumetric bone mineral density at the distal radius (d=1.06). Participation in gymnastics during pre-pubertal growth was associated with skeletal health benefits, particularly to the upper body.
Publisher: Wiley
Date: 08-03-2022
DOI: 10.1002/JBM4.10615
Abstract: High‐dose vitamin D supplementation (4000 or 10,000 IU/d) in vitamin D‐sufficient in iduals results in a dose‐dependent decrease in radius and tibia total bone mineral density (Tt.BMD) compared with 400 IU/d. This exploratory analysis examined whether the response to high‐dose vitamin D supplementation depends on imaging modality and skeletal site. Participants were aged 55 to 70 years, not osteoporotic, with serum 25(OH)D 30 to 125 nM. Participants’ radius and tibia were scanned on high‐resolution peripheral quantitative computed tomography (HR‐pQCT) to measure Tt.BMD, trabecular bone volume fraction (Tb.BV/TV), trabecular separation (Tb.Sp), cortical thickness (Ct.Th), and finite element analysis (FEA) estimated failure load. Three‐dimensional image registration was used. Dual‐energy X‐ray absorptiometry (DXA) scans of the hip, spine, and radius measured areal BMD (aBMD) and trabecular bone score (TBS). Constrained linear mixed‐effects models determined treatment group‐by‐time and treatment group‐by‐time‐by‐sex interactions. The treatment group‐by‐time interaction previously observed for radial Tt.BMD was observed at both ultradistal (UD, p 0.001) and 33% ( p 0.001) aBMD sites. However, the treatment group‐by‐time‐by‐sex interaction observed for radial Tt.BMD was not observed with aBMD at either the UD or 33% site, and the 4000 and 400 groups did not differ. Registered radial FEA results mirrored Tt.BMD. An increase in Tb.Sp and decrease in Ct.Th underpinned dose‐dependent changes in radial BMD and strength. We observed no effects in DXA‐based aBMD at the hip or spine or TBS. At the tibia, we observed a time‐by‐treatment group effect for Tb.BV/TV. Given that DXA measures at the radius did not detect sex differences or differences between the 4000 and 400 groups, HR‐pQCT at the radius may be more sensitive for examining bone changes after vitamin D supplementation. Although DXA did not reveal treatment effects at the hip or spine, whether that is a true skeletal site difference or a lack of modality sensitivity remains unclear. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
Publisher: Wiley
Date: 16-04-2018
DOI: 10.1002/ECE3.4016
Location: Australia
No related grants have been discovered for Lauren Burt.