Reporting of paediatric osteoporotic vertebral fractures in Duchenne muscular dystrophy and potential impact on clinical management: the need for standardised and structured reporting

BACKGROUND

In boys with Duchenne muscular dystrophy (DMD), initiation of bisphosphonate is recommended upon identification of moderate or severe vertebral fractures, even if asymptomatic. Clear radiological reporting is important for consistency of clinical interpretation and management.

OBJECTIVES

To audit radiology reports of spine imaging for vertebral fracture assessment in DMD, and assess potential impact on diagnosis and management.

MATERIALS AND METHODS

Lateral thoracolumbar spine imaging (71 lateral spine radiographs and 13 lateral dual energy absorptiometry spine image) in 84 boys with DMD performed across two centres. Anonymised radiology reports by paediatric radiologists were circulated to two neuromuscular clinicians and two endocrinologists. Clinicians determined if there was vertebral fracture, no vertebral fracture, or unclear interpretation. Endocrinologists also determined if bisphosphonate was indicated. A single observer (a clinician with expertise in vertebral fracture assessment) performed vertebral fracture assessment in 37 images and re-reported using a structured format. Structured reports were re-circulated to the four clinicians to re-evaluate the degree of concordance in clinical diagnosis of vertebral fracture and treatment decisions with bisphosphonate.

RESULTS

The term "fracture" was used in 25/84 (30%) radiology reports and only in 8/43 (19%) with description of vertebral body abnormalities. Fracture grading was included in 7/43 (16%) radiology reports. Diagnostic concordance by the clinicians was noted in 36/84 (43%). Unclear interpretation was noted in 22% to 51% based on radiology reports. No unclear interpretation was noted with structured reports. Complete diagnostic (37/37, 100%) and treatment (37/37, 100%) concordance was noted with the structured reports, whereas complete diagnostic and treatment concordance was noted in only 16/37 (43%) and 17/37 (46%) of the radiology reports, respectively.

CONCLUSION

Only a third of radiology reports of spine imaging in DMD explicitly used the terminology "fracture". Grading was only noted in a small percentage. Variability in diagnostic interpretation by clinicians may lead to differing management plans. As identification of vertebral fracture is a trigger for treatment, developing reporting guidelines for paediatric vertebral fracture assessment will improve care. A structured template should be introduced for radiological reporting of paediatric vertebral fracture assessment.

Emergency and perioperative management of adrenal insufficiency in children and young people: British Society for Paediatric Endocrinology and Diabetes consensus guidance

Adrenal insufficiency (AI) is characterised by lack of cortisol production from the adrenal glands. This can be a primary adrenal disorder or secondary to adrenocorticotropic hormone deficiency or suppression from exogenous glucocorticoids. Symptoms of AI in children may initially be non-specific and include growth faltering, lethargy, poor feeding, weight loss, abdominal pain, vomiting and lingering illnesses. AI is treated with replacement doses of hydrocortisone. At times of physiological stress such as illness, trauma or surgery, there is an increased requirement for exogenous glucocorticoids, which if untreated can lead to an adrenal crisis and death. There are no unified guidelines for those <18 years old in the UK, leading to substantial variation in the management of AI. This paper sets out guidance for intercurrent illness, medical, dental and surgical procedures to allow timely and appropriate recognition and treatment of AI and adrenal crisis for children and young people.

Anti-RANKL Therapy Prevents Glucocorticoid-Induced Bone Loss and Promotes Muscle Function in a Mouse Model of Duchenne Muscular Dystrophy

Bisphosphonates prevent bone loss in glucocorticoid (GC)-treated boys with Duchenne muscular dystrophy (DMD) and are recommended as standard of care. Targeting receptor activator of nuclear factor kappa-B ligand (RANKL) may have advantages in DMD by ameliorating dystrophic skeletal muscle function in addition to their bone anti-resorptive properties. However, the potential effects of anti-RANKL treatment upon discontinuation in GC-induced animal models of DMD are unknown and need further investigation prior to exploration in the clinical research setting. In the first study, the effects of anti-RANKL and deflazacort (DFZ) on dystrophic skeletal muscle function and bone microstructure were assessed in mdx mice treated with DFZ or anti-RANKL, or both for 8 weeks. Anti-RANKL and DFZ improved grip force performance of mdx mice but an additive effect was not noted. However, anti-RANKL but not DFZ improved ex vivo contractile properties of dystrophic muscles. This functional improvement was associated with a reduction in muscle damage and fibrosis, and inflammatory cell number. Anti-RANKL treatment, with or without DFZ, also improved trabecular bone structure of mdx mice. In a second study, intravenous zoledronate (Zol) administration (1 or 2 doses) following 2 months of discontinuation of anti-RANKL treatment was mostly required to record an improvement in bone microarchitecture and biomechanical properties in DFZ-treated mdx mice. In conclusion, the ability of anti-RANKL therapy to restore muscle function has profound implications for DMD patients as it offers the possibility of improving skeletal muscle function without the steroid-related skeletal side effects.

The prevalence of hypertension in paediatric Turner syndrome: a systematic review and meta-analysis

Cardiovascular related deaths account for over 40% of the excess mortality in Turner syndrome (TS). Hypertension, a modifiable risk factor for both aortic dilatation and dissection, is more commonly encountered in TS during childhood and adolescence. Treatment of hypertension is currently recommended beyond the age of 16 years in TS to help reduce the risk of aortic dissection. This study aims to determine the prevalence of hypertension in paediatric patients with TS and explore the associated methodologies of blood pressure evaluation reported in these studies. Three online databases were searched (Medline, Embase and Web of Science) for literature which reported a prevalence, or allowed calculation of prevalence, of hypertension in patients with TS who were 18 years of age or younger. Seventeen studies which met the primary eligibility criteria, with a total of 1948 patients, were included. The estimated pooled prevalence of hypertension in children and adolescents with TS was 16% (95% CI: 8.9-24.6%). There was significant heterogeneity detected between the studies. The prevalence of hypertension in those studies which assessed 24-h Ambulatory Blood Pressure Monitoring (ABPM) was 21.1% (95% CI: 15.2-27.6%) compared those which used another method of blood pressure measurement which was 13.5% (95% CI: 5.2-24.4%). Given the impact of hypertension with long-term health outcomes and the reversibility of these same outcomes by addressing abnormal blood pressure, prompt and early diagnosis of hypertension in young girls with TS should be prioritised. We recommend the use of 24-h ABPM in screening for hypertension in the paediatric TS population.

Analysis of the injury severity of motor vehicle-pedestrian crashes at urban intersections using spatiotemporal logistic regression models

This paper conducted a comprehensive study on the injury severity of motor vehicle-pedestrian crashes at 489 urban intersections across a dense road network based on high-resolution accident data recorded by the police from 2010 to 2019 in Hong Kong. Given that accounting for the spatial and temporal correlations simultaneously among crash data can contribute to unbiased parameter estimations for exogenous variables and improved model performance, we developed spatiotemporal logistic regression models with various spatial formulations and temporal configurations. The results indicated that the model with the Leroux conditional autoregressive prior and random walk structure outperformed other alternatives in terms of goodness-of-fit and classification accuracy. According to the parameter estimates, pedestrian age, head injury, pedestrian location, pedestrian actions, driver maneuvers, vehicle type, first point of collision, and traffic congestion status significantly affected the severity of pedestrian injuries. On the basis of our analysis, a range of targeted countermeasures integrating safety education, traffic enforcement, road design, and intelligent traffic technologies were proposed to improve the safe mobility of pedestrians at urban intersections. The present study provides a rich and sound toolkit for safety analysts to deal with spatiotemporal correlations when modeling crashes aggregated at contiguous spatial units within multiple years.

Comparison of adhesive single-lead cardiac ECG patch device with Holter monitoring for detecting atrial fibrillation after an acute cerebral ischemic event: An interim analysis

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health Malaysia

Background

Stroke secondary to atrial fibrillation (AF) is common and often associated with higher risk of stroke recurrence. Detection of AF is challenging due to brief unpredictable episodes of AF runs, especially in patients whose admission electrocardiogram (ECG) demonstrates a sinus rhythm. Probability of AF detection may be higher with early initiation of prolonged ECG monitoring.

Purpose

To compare diagnostic yield of 7-day cardiac ECG patch versus 24-hour Holter monitoring for detecting AF≥30 seconds; to identify predictors of AF in stroke patients; to determine if 7-day cardiac ECG patch results in a change in clinical practice.

Methods

In this investigator-initiated prospective study with pairwise comparison of 24-hour Holter and 7-day cardiac ECG patch monitoring, 150 patients who were admitted to a tertiary referral centre with acute ischemic stroke (AIS) or transient ischemic attack (TIA) within 1 week, without known AF, and had sinus rhythm in the admission 12-lead ECG were enrolled. Each patient underwent simultaneous 24-hour Holter and 7-day cardiac ECG patch monitoring. Routine transthoracic echocardiography was performed on each patient to assess cardiac function and exclude intracardiac thrombus.

Results

There were 102 (68.0%) male patients. 12 (8.0%) patients had underlying history of coronary artery disease; 26 (17.3%) had recurrent stroke or TIA. On admission, median NIH Stroke scale was 4; 18 (12.0%) patients had thrombolysis with alteplase. On transthoracic echocardiography, none had intracardiac thrombus.

Both Holter and cardiac ECG patch monitoring were initiated simultaneously at median 2 days after index stroke event. Of 150 patients, 17 (11.3%) detected AF ≥30 seconds. Of these 17 patients, 7 (4.7%) had AF detected within the first 24 hours on both Holter and cardiac ECG patch; 10 (6.7%) were detected after 24 hours on cardiac ECG patch only. Number needed to screen to detect one AF was 6. Compliance to 7-day cardiac ECG patch monitoring was 81.3%.

There was no significant difference in age among patients with and without AF. Although left atrium (LA) was not found to be dilated in patients with AF, LA volume index was significantly higher (28.3±15.9 vs 21.8±8.5, p=0.018) and LA emptying fraction (LAEF) was significantly lower (38.0%±30.2 vs 52.6%±16.7, p=0.007). The prolonged 7-day cardiac ECG monitoring patch resulted in 1.5-fold increase in prescription of anticoagulation therapy.

Conclusions

A 7-day cardiac ECG patch monitoring detected more patients with AF ≥30 seconds than 24-hour Holter monitoring and resulted in increase in prescription of anticoagulation therapy. Higher LA volume index and lower LA emptying fraction were predictors of AF in patients with a recent stroke.

The Physiology and Mechanisms of Growth

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An assessment of the effect of green signal countdown timers on drivers' behavior and on road safety at intersections, based on driving simulator experiments and naturalistic observation studies

INTRODUCTION

Motor-vehicle crashes at signalized intersections are a significant traffic safety problem. To address this problem, many Asian cities have installed signal countdown displays at signalized intersections, aiming to assist drivers to make correct decisions in response to traffic signals.

METHOD

In this study, we assessed the short-term and long-term effects of green signal countdown timers (GSCTs) on road safety, using a combination of driving simulator experiments and naturalistic observations.

RESULTS

In our driving simulator experiments, 80 participants drove at 50 km/h in scenarios in which a car either approached a signalized intersection alone or following another car. In naturalistic observations, short-term (1-week) and long-term (1-year) intersection safety in the presence and absence of GSCTs were compared. These observations revealed that GSCTs reduced the number of red-light-running violations over the short term, but not over the long term. In fact, GSCTs appeared to lead to an overall increase in rear-end crash risk at intersections, as their presence resulted in drivers exhibiting more sudden acceleration and braking, and altered intersection-crossing speeds and patterns.

CONCLUSIONS

The results suggest that GSCTs worsen safety at signalized intersections, and thus their removal should be considered.

3T-MRI-based age, sex and site-specific markers of musculoskeletal health in healthy children and young adults

Objective

The aim of this study is to investigate the role of 3T-MRI in assessing musculoskeletal health in children and young people.

Design

Bone, muscle and bone marrow imaging was performed in 161 healthy participants with a median age of 15.0 years (range, 8.0, 30.0).

Methods

Detailed assessment of bone microarchitecture (constructive interference in the steady state (CISS) sequence, voxel size 0.2 × 0.2 × 0.4 mm3), bone geometry (T1-weighted turbo spin echo (TSE) sequence, voxel size 0.4 × 0.4 × 2 mm3) and bone marrow (1H-MRS, point resolved spectroscopy sequence (PRESS) (single voxel size 20 × 20 × 20 mm3) size and muscle adiposity (Dixon, voxel size 1.1 × 1.1 × 2 mm3).

Results

There was an inverse association of apparent bone volume/total volume (appBV/TV) with age (r = -0.5, P < 0.0005). Cortical area, endosteal and periosteal circumferences and muscle cross-sectional area showed a positive association to age (r > 0.49, P < 0.0001). In those over 17 years of age, these parameters were also higher in males than females (P < 0.05). This sex difference was also evident for appBV/TV and bone marrow adiposity (BMA) in the older participants (P < 0.05). AppBV/TV showed a negative correlation with BMA (r = -0.22, P = 0.01) which also showed an association with muscle adiposity (r = 0.24, P = 0.04). Cortical geometric parameters were highly correlated with muscle area (r > 0.57, P < 0.01).

Conclusions

In addition to providing deep insight into the normal relationships between bone, fat and muscle in young people, these novel data emphasize the role of MRI as a non-invasive method for performing a comprehensive and integrated assessment of musculoskeletal health in the growing skeleton.

Uncertainty matters: Bayesian modeling of bicycle crashes with incomplete exposure data

BACKGROUND

One major challenge faced by neighborhood-level bicycle safety analysis is the lack of complete and reliable exposure data for the entire area under investigation. Although the conventional travel-diary surveys, together with the emerging smartphone fitness applications and bike-sharing systems, provide straightforward and valuable opportunities to estimate territory-wide bicycle activities, the obtained ridership suffers inherently from underreporting.

METHODS

We introduced the Bayesian simultaneous-equation model as a sound methodological alternative here to address the uncertainty arising from incomplete exposure data when modeling bicycle crashes. The proposed method was successfully fitted to a crowdsourced dataset of 792 bicycle-motor vehicle (BMV) crashes aggregated from 209 neighborhoods over a 3-year period in Hong Kong.

RESULTS

Our analysis empirically demonstrated the bias due to omission of activity-based exposure measures or to the direct use of cycling distance extracted from the travel-diary survey without correcting for incompleteness. By modeling bicycle activities and the frequency of BMV crashes simultaneously, we also provided new evidence that an expansion of bicycle infrastructure was likely associated with a significant increase in cycling levels and a substantial reduction in the risk of BMV crashes, despite a slight increase in the absolute number of BMV crashes.

CONCLUSIONS

Our approach is promising in adjusting for the uncertainty in raw exposure data, extrapolating the missing exposure values, and untangling the linkage among built environment, bicycle activities, and the frequency of BMV crashes within a unified framework. To promote safer cycling, designated facilities should be provided to consecutively separate cyclists from motor vehicles.

Evaluation of Body Composition in Paediatric Osteogenesis Imperfecta

Osteogenesis Imperfecta (OI) is a skeletal disorder characterised by a predisposition to recurrent fractures and bone deformities. Clinically OI is defined by features such as short stature, however, less is known regarding body composition. Assess body composition, both lean mass and fat mass, in a paediatric OI population. Children with OI attending the Bone service at the Royal Hospital for Children Glasgow were included; who had a dual-energy x-ray absorptiometry (DXA) scan performed 2015-2018. Height and body-mass-index (BMI) were converted to standard-deviation scores (SDS) using UK population references. DXA-derived lean mass and fat mass were used to generate lean-mass-index (LMI) and fat-mass-index (FMI) by dividing the covariates by height squared. LMI and FMI were converted to age-and-gender-adjusted SDS using DXA data from 198 local healthy children. Thirty-eight children (20 males) with median age 11.95 (range: 4.8, 18.3) years were included. Median height SDS was -1.08 (-3.64, 1.62) and was significantly lower than the healthy population (p<0.0001). Median BMI SDS was -0.10 (-2.31, 2.95), and not significantly different from the healthy population (p = 0.53). Median LMI SDS was -2.52 (-6.94, 0.77), and significantly lower than healthy controls (p<0.0001); 61% (23/38) had an SDS below -2.0. Median FMI SDS was 0.69 (-0.45, 2.72), significantly higher than healthy controls (p < 0.0001). BMI SDS cut-offs of -0.15 and 1.33, from ROC analysis, identified children with LMI SDS <-2, with a positive predictive value of 95% and a negative predictive value of 70%; and FMI SDS >2 with a positive predictive value of 44% and a negative predictive value of 100%. A contemporary population of children with ranging severities of OI present with significant reduction in height and lean mass, and relatively high fat mass. Standard BMI SDS cut-offs for identifying children with malnutrition and obesity have poor prognostic validity in OI.

Two-year plaque level outcomes involving the left anterior descending artery: insights from the Lipid-Rich Plaque study

Background

Coronary artery disease (CAD) is more frequently seen in the left anterior descending artery (LAD). LAD disease resulting in an acute anterior wall myocardial infarction (MI) is associated with a low left ventricular ejection fraction and invariably a worsened prognosis. The Lipid Rich Plaque (LRP) Study reported the strong association between NIRS-IVUS derived max4mmLCBI and future plaque events in non-culprit vessels.

Objective

To report the events involving the LAD versus the other major coronary vessels in the Lipid-Rich Plaque study.

Methods

The LRP Study was an international, multicenter, prospective cohort study conducted in patients with suspected CAD who underwent cardiac catheterization with possible ad hoc percutaneous coronary intervention (PCI) for an index event. Plaque level events within the subsequent 2 years were adjudicated. Plaque level events were defined as the composite of cardiac death, cardiac arrest, non-fatal MI, acute coronary syndrome (ACS), revascularization by coronary artery bypass grafting (CABG) or PCI, and rehospitalization for angina with &gt;20% stenosis progression related and unrelated to the treatment at index procedure. All together these events were reported as Non-Culprit Lesion-related Major Adverse Cardiac Events (NC-MACE). Prespecified subgroups of segments were defined according to LAD (vs. non-LAD) with maxLCBI4mm ≤400 or &gt;400.

Results

A total of 57 plaque events occurred through 2 years of follow-up. More than half occurred in the LAD, followed by the LCX and the RCA. There were more, albeit non-statistically significant, lipid-rich plaques in the LAD, compared to the LCX and RCA: 12.5% vs 10.4% and 11.3%, respectively, p=0.097. A minimum lumen area (MLA) ≤4mm2 within the maxLCBI4mm was observed more in the LAD and the LCX, compared to the RCA: 34.1% vs 25.9% vs 13.7%, respectively, p&lt;0.001. Lipid rich plaque (maxLCBI4mm&gt;400) was present in 20/57 (35.1%) of the plaque level events, a large PB (≥70%) was present in 6/57 (10.5%), and a small MLA (≤4mm2) was present in 26/57 (45.6%). Out of the 57 plaque level events, 4 (7%) had all three high risk plaque characteristics.

Presence of an elevated maxLCBI4mm (&gt;400) was predictive of NC-MACE in all subgroups (for LAD &gt;400 HR 4.32; 95% CI (1.93, 9.69; p 0.0004) and for the non-LAD &gt;400 HR 2.56; 95% CI (1.06, 6.17; p 0.0354).

Conclusion

Non-culprit segments in the LAD with maxLCBI4mm values &gt;400 were more frequently associated with plaque level events than in the lipid -rich segments in the other epicardial vessels. This sub-study results point to the unequivocal value of maxLCBI4mm&gt;400 in predicting future plaque level events especially in the LAD.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Infraredx Plaque Events-Ware Segment Locations

Observer Agreement of Vertebral Fracture Grading Using Dual Energy Absorptiometry Vertebral Fracture Assessment in Duchenne Muscular Dystrophy

Routine screening of the spine for vertebral fracture is recommended in the recent international standards of care for boys with Duchenne muscular dystrophy (DMD). Recent international consensus endorses the use of dual energy absorptiometry vertebral fracture assessment for identification of vertebral fractures in children, which could be used instead of spine radiographs. This study aims to evaluate the inter-observer agreement for vertebral fracture classification in boys with DMD, and the impact on clinical management. Dual energy absorptiometry vertebral fracture assessment and morphometric analysis in 39 boys was performed by a reader with no prior experience (R1) and 2 readers with experience (R2 and R3). Inter-observer concordance of vertebral fracture grading comparing R1 with R2 and R3 was substantial (Kappa 0.66, 95% CI 0.56, 0.76). Concordance between R2 and R3 was almost perfect (Kappa 0.93, 95% CI 0.89, 0.97) which did not lead to differences in clinical management. Grading by R1 in comparison to R2 and R3 would have led to change in management of 5/39 boys (13%), according to recent standards of care guidance. Structured education programme on identification of vertebral fractures should be explored to ensure consistency of reporting of this important health outcome measure in DMD.

On random-parameter count models for out-of-sample crash prediction: Accounting for the variances of random-parameter distributions

One challenge faced by the random-parameter count models for crash prediction is the unavailability of unique coefficients for out-of-sample observations. The means of the random-parameter distributions are typically used without explicit consideration of the variances. In this study, by virtue of the Taylor series expansion, we proposed a straightforward yet analytic solution to include both the means and variances of random parameters for unbiased prediction. We then theoretically quantified the systematic bias arising from the omission of the variances of random parameters. Our numerical experiment further demonstrated that simply using the means of random parameters to predict the number of crashes for out-of-sample observations is fundamentally incorrect, which necessarily results in the underprediction of crash counts. Given the widespread use and ongoing prevalence of the random-parameter approach in crash analysis, special caution should be taken to avoid this silent pitfall when applying it for predictive purposes.

Pathogenesis of Musculoskeletal Deficits in Children and Adults with Inflammatory Bowel Disease

Musculoskeletal deficits are among the most commonly reported extra-intestinal manifestations and complications of inflammatory bowel disease (IBD), especially in those with Crohn’s disease. The adverse effects of IBD on bone and muscle are multifactorial, including the direct effects of underlying inflammatory disease processes, nutritional deficits, and therapeutic effects. These factors also indirectly impact bone and muscle by interfering with regulatory pathways. Resultantly, individuals with IBD are at increased risk of osteoporosis and sarcopenia and associated musculoskeletal morbidity. In paediatric IBD, these factors may contribute to suboptimal bone and muscle accrual. This review evaluates the main pathogenic factors associated with musculoskeletal deficits in children and adults with IBD and summarises the current literature and understanding of the musculoskeletal phenotype in these patients.

Skeletal disproportion in girls with Turner syndrome and longitudinal change with growth-promoting therapy

OBJECTIVE

Short stature in Turner syndrome (TS) may be accompanied by skeletal disproportion. This retrospective study investigates growth and disproportion from early childhood to adult height.

STUDY DESIGN

Data were collected from 59 girls prior to growth hormone (rhGH) treatment and in 30 girls followed up longitudinally. Standard deviation scores (SDS) for height (Ht), sitting height (SH) and sub-ischial leg length (LL) were compared and a disproportion score (SH SDS - LL SDS) calculated.

RESULTS

In 59 girls, mean (SD) age 6.6 (2.1) years prior to rhGH treatment, LL SDS of -3.4 (1.1) was significantly lower than SH SDS of -1.2 (0.8) [p < .001]. In girls with Ht SDS < -2.0, disproportion score was > +2.0 in 27 (63%), cf eight (50%) with Ht SDS ≥ -2.0. For the longitudinal analysis, skeletal disproportion prior to rhGH was +2.4 (1.1) and +1.7 (1.0) on rhGH but prior to introduction of oestrogen [p < .001]. Disproportion at adult height was +1.1 (0.8), which was less marked than at the earlier time points [p < .001 for both comparisons]. Change in disproportion SDS over the first two years of rhGH predicted overall change in disproportion from baseline to adult height [R² 51.7%, p < .001].

CONCLUSION

TS is associated with skeletal disproportion, which is more severe in the shortest girls and present in only half of those with milder degrees of short stature. Growth-promoting therapy may improve disproportion during both the childhood and pubertal phases of growth. Change in disproportion status two years after starting rhGH helps predict disproportion at adult height.

Findings from the first public COVID-19 temporary test centre in Hong Kong

INTRODUCTION

The Hospital Authority of Hong Kong Special Administrative Region established a coronavirus disease 2019 (COVID-19) temporary test centre at the AsiaWorld-Expo from March 2020 to April 2020, which allowed high-risk individuals to undergo early assessment of potential severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This study reviewed the characteristics and outcomes of individuals who attended the centre for COVID-19 testing.

METHODS

This retrospective cross-sectional study collected epidemiological and clinical data. The primary outcome was a positive or negative SARS-CoV-2 test result, according to reverse transcription polymerase chain reaction analyses of pooled nasopharyngeal and throat swabs collected at the centre. The relationships of clinical characteristics with SARS-CoV-2 positive test results were assessed by multivariable binary logistic regression.

RESULTS

Of 1258 attendees included in the analysis, 86 individuals tested positive for SARS-CoV-2 infection (positivity rate=6.84%; 95% confidence interval [CI]=5.57%-8.37%). Of these 86 individuals, 40 (46.5%) were aged 15 to 24 years and 81 (94.2%) had a history of recent travel. Symptoms were reported by 86.0% and 96.3% of individuals with positive and negative test results, respectively. The clinical characteristics most strongly associated with a positive test result were anosmia (adjusted odds ratio [OR_adj]=8.30; 95% CI=1.12-127.09) and fever OR_adj=1.32; 95% CI=1.02-3.28).

CONCLUSION

The temporary test centre successfully helped identify individuals with COVID-19 who exhibited mild disease symptoms. Healthcare providers should carefully consider the epidemiological and clinical characteristics of COVID-19 to arrange early testing to reduce community spread.

Right-looking habit and maladaptation of pedestrians in areas with unfamiliar driving rules

Both left-driving (LD) and right-driving (RD) rules are used around the world. When traveling to places with different driving rules, pedestrians are likely to make mistakes. To investigate the frequency of such mistakes, a case study was conducted with pedestrians in Hong Kong, which follows LD rules, i.e., traffic drives on the left. The study aimed to probe the effects of hometown driving rules and length of stay on pedestrians' right-looking habit and maladaptation to the Hong Kong LD system and determine the mediating effect of the right-looking habit. A face-to-face survey was conducted with 581 respondents at seven locations in Hong Kong. A structural equation model was applied to determine the relationship among hometown driving rules, length of stay, right-looking habit, and maladaptation. The model exhibited good fitness (χ²/degrees of freedom=2.154; comparative fit index=0.989; Tucker-Lewis Index=0.980; and root mean square error of approximation=0.045). The results revealed that hometown driving rules and length of stay had positive effects on the right-looking habit, and hometown driving rules had a direct negative effect on maladaptation. The right-looking habit partially mediated the effect of hometown driving rules and fully mediated the effect of length of stay on maladaptation to the Hong Kong LD system. It was found that when foreign pedestrians were in areas with unfamiliar driving rules, they tended to practice their hometown looking habits, especially foreign pedestrians who had stayed only for a short time; this behavior differed significantly from that of local pedestrians, and it led to more severe maladaptation. The findings of this study provide empirical evidence of pedestrians' looking habits and maladaptation in areas with unfamiliar driving systems and have significant implications for improving the safety of foreign pedestrians.

Towards activity-based exposure measures in spatial analysis of pedestrian-motor vehicle crashes

BACKGROUND

Although numerous efforts have been devoted to exploring the effects of area-wide factors on the frequency of pedestrian crashes in neighborhoods over the past two decades, existing studies have largely failed to provide a full picture of the factors that contribute to the incidence of zonal pedestrian crashes, due to the unavailability of reliable exposure data and use of less sound analytical methods.

METHODS

Based on a crowdsourced dataset in Hong Kong, we first proposed a procedure to extract pedestrian trajectories from travel-diary survey data. We then aggregated these data to 209 neighborhoods and developed a Bayesian spatially varying coefficients model to investigate the spatially non-stationary relationships between the number of pedestrian-motor vehicle (PMV) crashes and related risk factors. To dissect the role of pedestrian exposure, the estimated coefficients of models with population, walking trips, walking time, and walking distance as the measure of pedestrian exposure were presented and compared.

RESULTS

Our results indicated substantial inconsistencies in the effects of several risk factors between the models of population and activity-based exposure measures. The model using walking trips as the measure of pedestrian exposure had the best goodness-of-fit. We also provided new insights that in addition to the unstructured variability, heterogeneity in the effects of explanatory variables on the frequency of PMV crashes could also arise from the spatially correlated effects. After adjusting for vehicle volume and pedestrian activity, road density, intersection density, bus stop density, and the number of parking lots were found to be positively associated with PMV crash frequency, whereas the percentage of motorways and median monthly income had negative associations with the risk of PMV crashes.

CONCLUSIONS

The use of population or population density as a surrogate for pedestrian exposure when modeling the frequency of zonal pedestrian crashes is expected to produce biased estimations and invalid inferences. Spatial heterogeneity should also not be negligible when modeling pedestrian crashes involving contiguous spatial units.

Clinical utility of urinary gonadotrophins in hypergonadotrophic states as Turner syndrome

Background Girls with Turner syndrome (TS) are at an increased risk of primary ovarian insufficiency (POI). Good correlation between serum and urinary gonadotrophins exists in children assessed for disorders of puberty, but there is little evidence of their reliability in hypergonadotropic states. Objectives To determine whether there was a correlation between serum and urinary Luteinising Hormone (uLH) and Follicle-Stimulating Hormone (uFSH) in hypergonadotrophic states, and whether uFSH could suggest an ovarian failure in TS as Anti-Mullerian Hormone (AMH). Patients and Methods Retrospective cohort study of 37 TS girls attending the paediatric TS clinic in Glasgow between February 2015 and January 2019, in whom 96 non-timed spot urine samples were available with a median age at time of sample of 12.89 years (3.07-20.2 years). uLH and uFSH were measured by chemiluminescent microparticle immunoassay. Simultaneous serum gonadotrophins and AMH were available in 30 and 26 girls, respectively. AMH <4 pmol/L was considered indicative of ovarian failure. Results A strong correlation was found between serum LH and uLH (r 0.860, P<0.001) and serum FSH and uFSH (r 0.905, p<0.001). Among patients≥10 years not on oestrogen replacement, ROC curve identified uFSH as a reasonable marker for AMH<4 pmol/L uFSH of >10.85 U/L indicates an AMH <4 pmol/L with 75% sensitivity and 100 % specificity (AUC 0.875)with similar ability as serum FSH (AUC 0.906). Conclusion uLH and uFSH are non-invasive, useful and reliable markers of ovarian activity in hypergonadotropic states as TS. uFSH could provide an alternative to AMH (in centres which are limited by availability or cost) in revealing ovarian failure and requirement for oestrogen replacement in pubertal induction.

A survey of the feasibility of developing osteoporosis clinical trials in Duchenne muscular dystrophy: Survey of the opinion of young people with Duchenne muscular dystrophy, families and clinicians

BACKGROUND/AIMS

Given the extent of osteoporosis in people with Duchenne muscular dystrophy treated with glucocorticoids and the limited evidence of bone-protective therapies, clinical trials are needed. We conducted surveys to obtain the opinion of young people with Duchenne muscular dystrophy, parents/guardians and neuromuscular clinicians on the feasibility of osteoporosis clinical trials in this population.

METHODS

Online surveys were sent to three groups: (a) people with a confirmed diagnosis of Duchenne muscular dystrophy (≥14 years), (b) parents and guardians and (c) neuromuscular clinicians in the UK NorthStar Clinical Network. Surveys (a) and (b) were distributed via the UK Duchenne muscular dystrophy Registry.

RESULTS

Survey respondents included 52 people with Duchenne muscular dystrophy with a median age of 17 years (range: 14, 40) and 183 parents/guardians. Fourteen out of 23 (61%) NorthStar centres responded. Of the 52 people with Duchenne muscular dystrophy, 13 (25%) were very concerned about their bone health and 21 (40%) were slightly concerned. Of the 183 parents/guardians, 75 (41%) were very concerned about their son's bone health and 90 (49%) were slightly concerned. Fractures and quality of life were the top two main outcome measures identified by people with Duchenne muscular dystrophy. Fractures and bone density were the top two main outcome measures identified by parents/guardians and neuromuscular clinicians. Thirty percent of people with Duchenne muscular dystrophy and 40% of parents/guardians would not take part if an osteoporosis trial involved a placebo that was administered parenterally. Only 2 of the 14 NorthStar centres (14%) would enrol people with Duchenne muscular dystrophy if a parenteral placebo was used in an osteoporosis trial in Duchenne muscular dystrophy.

CONCLUSION

There is great awareness of bone health and the need for bone-protective trials among people with Duchenne muscular dystrophy and their carers. However, a proportion of people with Duchenne muscular dystrophy and parents are reluctant to participate in a placebo-controlled osteoporosis trial that included a parenteral therapy. A larger proportion of health care experts are unwilling to enrol their patients in such a trial. Our finding is relevant for the design of bone-protective studies in Duchenne muscular dystrophy.

Severity of passenger injuries on public buses: A comparative analysis of collision injuries and non-collision injuries

INTRODUCTION

Although public buses have been demonstrated as a relatively safe mode of transport, the number of injuries to public bus passengers is far from negligible. Existing studies of public bus safety have focused primarily on injuries caused by collisions. Surprisingly, limited effort has been devoted to identifying factors that increase the severity of passenger injuries in non-collision incidents.

METHOD

Our study therefore investigated the injury risk of public bus passengers involved in collision incidents and non-collision incidents comparatively, based on a police-reported dataset of 17,383 passengers injured on franchised public buses over a 10-year period in Hong Kong. A random parameters logistic model was established to estimate the likelihood of fatal and severe injuries to passengers as a function of various factors.

RESULTS

Our results indicated substantial inconsistences in the effects of risk factors between models of non-collision injuries and collision injuries. The severity of passenger injuries tended to increase significantly when non-collision incidents occurred due to excessive speed of bus drivers, on double-decker buses, in less urbanized areas, in winter, in heavy rains, during daytime, and at night without street lighting. Elderly female passengers were also found more likely to be fatally or severely injured in non-collision incidents if they lost their balance while boarding, alighting from, or standing on a bus. In comparison, the following factors were associated with a greater likelihood of fatal or severe injuries in collision incidents: elderly female passengers, standing passengers who lost balance, buses out of driver control, double-decker buses, collisions with vehicles or objects, and less urbanized areas. Practical Applications: Based on our comparative analysis, more targeted countermeasures, namely "4E" (engineering, enforcement, emergency, and education) and "3A" (awareness, appreciation, and assistance), were recommended to mitigate collision injuries and non-collision injuries to public bus passengers, respectively.

Risks to pedestrians in traffic systems with unfamiliar driving rules: a virtual reality approach

In this study, a virtual-reality (VR) pedestrian simulation method was used to evaluate the risks to pedestrians crossing streets in a traffic system with driving rules that were unfamiliar to them. Pedestrians from mainland China (which has a right-side driving (RD) system) and Hong Kong (which has a left-side driving (LD) system) were studied. Significant differences were observed between pedestrians from the different locations in terms of the direction in which the pedestrians habitually first looked before crossing. When exposed to an unfamiliar driving rule (i.e., traffic coming from an inconsistent direction in terms of participants' habitual driving system), the odds of participants from mainland China making an error in their looking behavior were 2.93 times those when exposed to a familiar driving rule. Road markings and traffic sound did not improve these participants' looking behavior. The results also show a negative correlation between inattentive looking behavior and time to collision (significant at the 1% level), as these errors lead to a shorter time to collision and increased the risk to pedestrians. The results of this study confirmed the risks for pedestrians traveling to places with unfamiliar driving rules and confirmed the existence of habitual looking behavior, and therefore provide evidence of the need for future studies to improve this problem. These may help decision makers take the risks of pedestrians from different driving rules into consideration in future traffic policymaking or traffic-facility improvements. The use of a VR simulation-based approach in this study provided a safe and controllable way to trial interventions and potential improvements without risking injury to participants, and thus may also be used for similar future studies.

Feasibility of Dual Energy X-Ray Absorptiometry Based Images for Measurement of Height, Sitting Height, and Leg Length in Children

BACKGROUND

Interpretation of pediatric bone mineral density by dual energy absorptiometry (DXA) requires adjustment for height (Ht). This is often not easily obtainable in nonambulant subjects.

AIMS

To investigate the feasibility of using DXA images to evaluate measurements of Ht, sitting height (SH), and leg length (LL).

METHODOLOGY

A total of 2 observers performed measurements of Ht, SH, and LL on 3 separate occasion using DXA digital images in 125 children. Intraclass correlation and relative technical error of measurement (rTEM) were performed to assess reliability of repeated measurements. In 25 children, Ht and SH were measured in clinic on the same day and Bland-Altman analysis was performed to compare DXA measured Ht, SH, LL with clinic measurements for these 25 children.

RESULTS

Intraclass correlation for DXA based Ht, SH, and LL measurements ranged from 0.996 to 0.998 (p < 0.0001). rTEM of Ht, SH, and LL for observer 1 was 0.0016%, 0.002%, and 0.0034%, respectively. rTEM of Ht, SH, and LL between observer 1 and 2 was 0.0047%, 0.0049%, and 0.0087%, respectively. Mean difference between clinic and DXA measurements from Bland-Altman plots were +0.57 cm (95% confidence interval [CI] -0.54 to +1.68) for Ht, +1.33cm (-1.60 to +4.24) for SH, and -0.76cm (-3.88 to +2.37) for LL.

CONCLUSIONS

Our study demonstrated for the first time that Ht, SH, and LL in children can be measured very precisely using DXA images. Ht can be measured accurately. We believe this may be a convenient method to obtain Ht measurements to allow size adjustment of DXA bone mineral density in immobile children with chronic conditions.

Fractures and Linear Growth in a Nationwide Cohort of Boys With Duchenne Muscular Dystrophy With and Without Glucocorticoid Treatment: Results From the UK NorthStar Database

Importance

Based on studies with relatively small sample size, fragility fractures are commonly reported in glucocorticoid (GC)-treated boys with Duchenne muscular dystrophy (DMD).

Objective

To determine the fracture burden and growth impairment in a large contemporary cohort of boys with DMD in the United Kingdom and in relation to GC regimen.

Design, Setting, and Participants

A retrospective review of fracture morbidity and growth from 832 boys with DMD in the UK NorthStar database (2006-2015), which systematically captures information from 23 participating centers. A total of 564 boys had more than 1 visit. No numbers of boys who refused were collected, but informal data from 2 centers in London and from Scotland show that refusal is very low. Data were analyzed between October 2006 and October 2015.

Main Outcomes and Measures

Fracture incidence rate per 10 000 person-years was determined. Cox regression analysis was used to identify factors associated with first fracture.

Results

Median age at baseline was 6.9 years (interquartile range, 4.9-7.2 years). At baseline, new fractures were reported in 7 of 564 participants (1.2%). During a median follow-up of 4 years (interquartile range, 2.0-6.0 years), incident fractures were reported in 156 of 564 participants (27.7%), corresponding to an overall fracture incidence rate of 682 per 10 000 person-years (95% CI, 579-798). The highest fracture incidence rate was observed in those treated with daily deflazacort at 1367 per 10 000 person-years (95% CI, 796-2188). After adjusting for age at last visit, mean hydrocortisone equivalent dose, mobility status, and bisphosphonate use prior to first fracture, boys treated with daily deflazacort had a 16.0-fold increased risk for first fracture (95% CI, 1.4-180.8; P = .03). Using adjusted regression models, change in height standard deviation scores was -1.6 SD lower (95% CI, -3.0 to -0.1; P = .03) in those treated with daily deflazacort compared with GC-naive boys, whereas there were no statistical differences in the other GC regimen.

Conclusions and Relevance

In this large group of boys with DMD with longitudinal data, we document a high fracture burden. Boys treated with daily deflazacort had the highest fracture incidence rate and the greatest degree of linear growth failure. Clinical trials of primary bone protective therapies and strategies to improve growth in boys with DMD are urgently needed, but stratification based on GC regimen may be necessary.

A comparison of the bone and growth phenotype of mdx, mdx:Cmah-/- and mdx:Utrn +/- murine models with the C57BL/10 wild-type mouse

The muscular dystrophy X-linked (mdx) mouse is commonly used as a mouse model of Duchenne muscular dystrophy (DMD). Its phenotype is, however, mild, and other mouse models have been explored. The mdx:Cmah^−/− mouse carries a human-like mutation in the Cmah gene and has a severe muscle phenotype, but its growth and bone development are unknown. In this study, we compared male mdx, mdx:Utrn^+/−, mdx:Cmah^−/− and wild-type (WT) mice at 3, 5 and 7 weeks of age to determine the suitability of the mdx:Cmah^−/− mouse as a model for assessing growth and skeletal development in DMD. The mdx:Cmah^−/− mice were lighter than WT mice at 3 weeks, but heavier at 7 weeks, and showed an increased growth rate at 5 weeks. Cortical bone fraction as assessed by micro-computed tomography was greater in both mdx and mdx:Cmah^−/− mice versus WT mice at 7 weeks. Tissue mineral density was also higher in mdx:Cmah^−/− mice at 3 and 7 weeks. Gene profiling of mdx:Cmah^−/− bone identified increased expression of Igf1, Igf1r and Vegfa. Both the mdx and mdx:Cmah^−/− mice showed an increased proportion of regulated bone marrow adipose tissue (BMAT) but a reduction in constitutive BMAT. The mdx:Cmah^−/− mice show evidence of catch-up growth and more rapid bone development. This pattern does not mimic the typical DMD growth trajectory and therefore the utility of the mdx:Cmah^−/− mouse for studying growth and skeletal development in DMD is limited. Further studies of this model may, however, shed light on the phenomenon of catch-up growth.

This article has an associated First Person interview with the first author of the paper.

Summary: Unlike boys with DMD, the mdx:Cmah^−/− mouse shows increased weight gain and more rapid bone development; therefore, its utility for studying growth and skeletal development in DMD is limited.

Systematic review of the effects of bisphosphonates on bone density and fracture incidence in childhood acute lymphoblastic leukaemia

Skeletal fragility is a common complication of childhood acute lymphoblastic leukaemia (ALL) but the impact of bisphosphonate therapy on bone mass and fracture is unclear. We aim to conduct a systematic review to evaluate the effects of bisphosphonates on bone mineral density (BMD) and fracture incidence in children with ALL.

METHODS

EMBASE, Medline and the Cochrane Library were thoroughly searched by two researchers. Inclusion criteria was any child under the age of 18 years with a diagnosis of ALL, who had received any bisphosphonate treatment and had serial measurements of bone density performed thereafter. All primary research studies of any study design, excluding case reports, were included.

RESULTS

Ten full text papers were identified with two exclusively meeting the inclusion criteria. Both studies administered bisphosphonates to children receiving maintenance chemotherapy for varying durations. Bone density was assessed at regular intervals by dual x-ray absorptiometry (DXA). The majority of participants had an improvement in bone density at the end of each study. However, no size adjustment of DXA data was performed. Limited information on fracture occurrence was provided by one study but did not include routine screening for vertebral fractures.

CONCLUSIONS

This systematic review identified that there is insufficient evidence to support routine use of prophylactic bisphosphonate therapy in childhood ALL for prevention of fracture and improvement of bone mass. Future well-designed clinical trials in those at highest risk of fractures in ALL are now needed.

Skeletal Fragility and Its Clinical Determinants in Children With Type 1 Diabetes

CONTEXT

Type 1 diabetes (T1D) is associated with an increased fracture risk at all ages.

OBJECTIVE

To understand the determinants of bone health and fractures in children with T1D.

DESIGN

Case-control study of children with T1D on bone-turnover markers, dual-energy X-ray absorptiometry, and 3 Tesla-MRI of the proximal tibia to assess bone microarchitecture and vertebral marrow adiposity compared with age- and sex-matched healthy children.

RESULTS

Thirty-two children with T1D at a median (range) age of 13.7 years (10.4, 16.7) and 26 controls, aged 13.8 years (10.2, 17.8), were recruited. In children with T1D, serum bone-specific alkaline phosphatase (BAP) SD score (SDS), C-terminal telopeptide of type I collagen SDS, and total body (TB) and lumbar spine bone mineral density (BMD) SDS were lower (all P < 0.05). Children with T1D also had lower trabecular volume [0.55 (0.47, 0.63) vs 0.59 (0.47, 0.63); P = 0.024], lower trabecular number [1.67 (1.56, 1.93) vs 1.82 (1.56, 1.99); P = 0.004], and higher trabecular separation [0.27 (0.21, 0.32) vs 0.24 (0.20, 0.33); P = 0.001] than controls. Marrow adiposity was similar in both groups (P = 0.25). Bone formation, as assessed by BAP, was lower in children with poorer glycemic control (P = 0.009) and who were acidotic at initial presentation (P = 0.017) but higher in children on continuous subcutaneous insulin infusion (P = 0.025). Fractures were more likely to be encountered in children with T1D compared with controls (31% vs 19%; P< 0.001). Compared with those without fractures, the T1D children with a fracture history had poorer glycemic control (P = 0.007) and lower TB BMD (P < 0.001) but no differences in bone microarchitecture.

CONCLUSION

Children with T1D display a low bone-turnover state with reduced bone mineralization and poorer bone microarchitecture.

Pubertal abnormalities in adolescents with chronic disease

Pubertal disorders in the context of chronic disease especially in those with chronic inflammatory disorders or those requiring prolonged periods of treatment with glucocorticoid are common reasons for referral to the paediatric endocrine clinic. Disorders of puberty are also common in adolescents with disability requiring management by paediatric endocrinologists. In these adolescents, impaired skeletal development is also observed and this can be associated with fragility fractures. Chronic inflammation, glucocorticoid and sub-optimal nutrition all impact on the hypothalamic-pituitary gonadal axis, and can also impact on skeletal development locally by their effects on the growth plate and bone. Addressing pubertal disorders is important to ensure adolescents with chronic disease are matched with their peers, promote adequate bone mass accrual and linear growth. Careful discussion with primary clinicians, the young person and the family is needed when instituting endocrine therapies to address puberty and manage bone health.

Temporal patterns of driving fatigue and driving performance among male taxi drivers in Hong Kong: A driving simulator approach

This study uses a questionnaire survey and a driving simulator test to investigate the temporal patterns of variations in driving fatigue and driving performance in 50 male taxi drivers in Hong Kong. Each driver visited the laboratory three times: before, during, and after a working shift. The survey contained a demographic questionnaire and the Brief Fatigue Inventory. A following-braking simulator test session was conducted at two speeds (50 and 80 km/h) by each driver at each of his three visits, and the driver's performance in brake reaction, lane control, speed control, and steering control were recorded. A random-effects modeling approach was incorporated to address the unobserved heterogeneity caused by the repeated measures. In the results, a recovery effect and a lagging effect were defined for the driving fatigue and performance measures because their temporal patterns were concavely quadratic and had a 1-hour delay compared to the temporal patterns of occupied taxi trips and taxi crash risk in Hong Kong. Demographic variables, such as net income and driver age, also had significant effects on the measured driving fatigue and performance. Policies regarding taxi management and operation based on the modeling results are proposed to alleviate the taxi safety situation in Hong Kong and worldwide.

Associations of dietary protein intake with bone mineral density: An observational study in 70,215 UK Biobank participants

PURPOSE

Adequate dietary protein intake is important for the maintenance of bone health; however, data in this area is ambiguous with some suggestion that high protein intake can have deleterious effects on bone health. The aim of the current study was to explore the associations of protein intake with bone mineral density (BMD).

METHODS

We used baseline data from the UK Biobank (participants aged 40-69 years) to examine the association of protein intake with BMD (measured by ultrasound). These associations were examined, in women (n = 39,066) and men (n = 31,149), after adjustment for socio-demographic and lifestyle confounders and co-morbidities.

RESULTS

Protein intake was positively and linearly associated with BMD in women (β-coefficient 0.010 [95% CI 0.005; 0.015, p < 0.0001]) and men (β-coefficient 0.008 [95% CI 0.000; 0.015, p = 0.044]); per 1.0 g/kg/day increment in protein intake, independently of socio-demographics, dietary factors and physical activity.

CONCLUSIONS

The current data have demonstrated that higher protein intakes are positively associated with BMD in both men and women. This indicates that higher protein intakes may be beneficial for both men and women.

Effects of Recombinant Human Growth Hormone in Children with Crohn's Disease on the Muscle-Bone Unit: A Preliminary Study

BACKGROUND/AIMS

There is limited information on the impact of recombinant human growth hormone (rhGH) on the muscle-bone unit in children with Crohn's disease (CD). In this pilot study, we report on the effects of rhGH on bone formation, dual-energy X-ray absorptiometry (DXA) total body (TB) bone mineral density adjusted for height and lumbar spine (LS) bone mineral apparent density (BMAD), and body composition.

METHODS

Prospective study of 8 children with CD (6 male), aged 14.8 years (9.0-16.4), who received rhGH for 24 months. Serum procollagen type 1 N-terminal propeptide (P1NP) was measured at baseline and at 6 months. DXA was performed every 6 months.

RESULTS

Six months of rhGH led to improvement in P1NP SDS adjusted for bone age from -3.6 (-7.9 to -0.9) to -2.4 (-3.7 to 0.4) (p = 0.01). At baseline, reduction in LS-BMAD and TB lean mass SDS was observed being -1.2 (-3.6 to 0.8) (p = 0.01 vs. zero) and -0.8 (-2.4 to 3.0) (p = 0.11 vs. zero), respectively. No significant changes were seen in DXA bone and muscle parameters over the 24 months.

CONCLUSION

Twenty-four months of therapy with rhGH in CD did not lead to an improvement in DXA BMD and lean mass, despite improvement in P1NP and linear growth.

Fractures and bone health monitoring in boys with Duchenne muscular dystrophy managed within the Scottish Muscle Network

There are limited reports of radiologically confirmed fractures and bone health monitoring in with Duchenne muscular dystrophy. We performed a retrospective study of 91 boys, with a median age of 11.0 years, who are currently managed in Scotland with the aim to assess the frequency of radiologically confirmed fractures and report on bone health monitoring in relation to International Care Consensus Guidance. Of these boys, 59 (65%) were receiving glucocorticoid (GC) therapy and 23 (25%) had received previous treatment. Of those currently on GC, 37 (63%) had an assessment of bone mineral density and none had routine imaging for vertebral fractures during the study period. Of the 91 boys, 44 (48%) had sustained at least one symptomatic radiographically confirmed fracture. The probability of sustaining a first symptomatic fracture was 50% by 12.8 years old (95%CI: 12.1, 13.6). The most common sites for non-vertebral fracture were the femur and tibia. In this review of boys with DMD, almost half had sustained at least one radiologically confirmed symptomatic fracture. There is a need for standardized bone health monitoring in DMD that includes routine imaging of the spine to identify vertebral fractures, given the persistence of insult to the skeleton in these boys.

Bayesian approach to model pedestrian crashes at signalized intersections with measurement errors in exposure

This study intended to identify the potential factors contributing to the occurrence of pedestrian crashes at signalized intersections in a densely populated city, based on a comprehensive dataset of 898 pedestrian crashes at 262 signalized intersections during 2010-2012 in Hong Kong. The detailed geometric design, traffic characteristics, signal control, built environment, along with the vehicle and pedestrian volumes were elaborately collected. A Bayesian measurement errors model was introduced as an alternative method to explicitly account for the uncertainties in volume data. To highlight the role played by exposure, models with and without pedestrian volume were estimated and compared. The results indicated that the omission of pedestrian volume in pedestrian crash frequency models would lead to reduced goodness-of-fit, biased parameter estimates, and incorrect inferences. Our empirical analysis demonstrated the existence of moderate uncertainties in pedestrian and vehicle volumes. Six variables were found to have a significant association with the number of pedestrian crashes at signalized intersections. The number of crossing pedestrians, the number of passing vehicles, the presence of curb parking, and the presence of ground-floor shops were positively related with pedestrian crash frequency, whereas the presence of playgrounds near intersections had a negative effect on pedestrian crash occurrences. Specifically, the presence of exclusive pedestrian signals for all crosswalks was found to significantly reduce the risk of pedestrian crashes by 43%. The present study is expected to shed more light on a deeper understanding of the environmental determinants of pedestrian crashes.

In-hospital infective endocarditis following transcatheter aortic valve replacement: a cross-sectional study of the National Inpatient Sample database in the USA

BACKGROUND

While the utilization of transcatheter aortic valve replacement (TAVR) for patients with severe aortic stenosis has been increasing, in-hospital infective endocarditis (IE) following TAVR has not been well described.

AIM

To identify in-hospital IE following TAVR.

METHODS

All patients who underwent TAVR between 2012 and 2014 were identified using the National Inpatient Sample database. Multi-variate logistic regression was performed to identify the predictors of in-hospital IE after TAVR.

FINDINGS

Of the 41,025 patients who received TAVR, 120 patients (0.3%) developed in-hospital IE. Viridans group streptococci (20.8%) was the most frequent causative organism for in-hospital IE, followed by Staphylococcus aureus (16.7%) and enterococci (8.3%). Patients who developed in-hospital IE after TAVR had significantly higher rates of death (20.8% vs 4.1%, P<0.001), septic shock (16.7% vs 0.8%, P<0.001), cardiogenic shock (12.5% vs 3.4%, P=0.02), acute kidney injury requiring haemodialysis (16.7% vs 1.6%, P<0.001), bleeding requiring transfusion (29.2% vs 11.3%, P=0.01), myocardial infarction (12.5% vs 2.1%, P<0.001) and permanent pacemaker removal (4.2% vs 0.05%, P<0.001) compared with patients without IE. Independent predictors of in-hospital IE after TAVR include younger age [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.89-0.95], drug abuse (OR 48.9, 95% CI 6.9-347.3) and human immunodeficiency virus (HIV) infection (OR 7.8, 95% CI 1.4-44.4).

CONCLUSION

IE occurred in 0.3% of patients after TAVR during the same hospitalization, resulting in higher rates of adverse outcomes including mortality. Patients with younger age, a history of drug abuse or HIV infection are at greater risk of in-hospital IE following TAVR, and would benefit from vigilant preventive measures perioperatively.

Ablation of Bax and Bak protects skeletal muscle against pressure-induced injury

Pressure-induced injury (PI), such as a pressure ulcer, in patients with limited mobility is a healthcare issue worldwide. PI is an injury to skin and its underlying tissue such as skeletal muscle. Muscle compression, composed of mechanical deformation of muscle and external load, leads to localized ischemia and subsequent unloading reperfusion and, hence, a pressure ulcer in bed-bound patients. Although the gross factors involved in PI have been identified, little is known about the exact disease mechanism or its links to apoptosis, autophagy and inflammation. Here, we report that PI is mediated by intrinsic apoptosis and exacerbated by autophagy. Conditional ablation of Bax and Bak activates the Akt-mTOR pathway and Bnip3-mediated mitophagy and preserves mitochondrial contents in compressed muscle. Moreover, we find that the presence/absence of Bax and Bak alters the roles and functions of autophagy in PI. Our results suggest that manipulating apoptosis and autophagy are potential therapeutic targets for treatment and prevention of PI.

Effects of Drink Driving on Crash Risk Based on Random Breath Test Data

Introduction

Driving under the influence of alcohol (DUIA) is an important contributor to road crashes, injuries, and fatalities. Legal limits on drivers' breath alcohol concentration (BrAC) were first introduced in Hong Kong during the 1990s. Since then, the number of alcohol-related crashes has decreased. In 2009, police were empowered to conduct random breath tests (RBT) at roadblocks at any time. The availability of comprehensive RBT data allows us to determine the relationship between crash risk and BrAC, while controlling for confounding factors such as temporal distribution, road environment, and traffic conditions.

Method

In this study, we established two negative binomial regression models to analyse the risk of crashes in which people are killed or seriously injured (KSI crashes) and those involving only slight injuries on 182 urban road segments.

Results

Our results indicated that a higher mean BrAC markedly increases the risk of KSI crashes. However, there was no relationship between the risk of crashes involving slight injury and mean BrAC, although the absence of a hard shoulder, the presence of roadside parking bays, the dawn period, and the location noticeably increase the risk of these crashes.

Conclusion

It is worth exploring the benefits of remedial measures if comprehensive information on demographics and the driving habits of individual drivers become available in the future.

Association between Drink Driving and Severity of Crash Injuries to Road Users

Objective

To determine the association between alcohol impairment in drivers and risk of severe injury in other road users in Hong Kong.

Method

The Road Casualty Injury Information System (RoCIS) was set up by linking a regional hospital injury registry to the police traffic injury database. Based on the year 2004 linked dataset, a specific model namely the External Casualty Model (ECM) was designed to measure the association between severe injury outcome of other (non-driver) road user casualties (as stratified by ISS groups [ISS <9 or ISS ≥9]) and the level of alcohol impairment (as measured by breath alcohol concentration [BAC <22 µg/100 ml or BAC ≥22 µg/100 ml]) in drivers involving in the crash, controlling for the driver's demographics (age and sex) and behaviour (as measured by driving-offence points [DOP]) and another attribute (day of week of crash). Binary logistic regression was used in the analysis.

Results

Out of 1818 matched RoCIS cases in the year 2004, 439 ECM records were available for analysis. Alcohol impaired drivers led to a significantly higher risk of severe injury to other road users (OR=4.2, 95%CI=1.21, 14.36, p=0.02). Crashes on weekdays seemingly led to a lower severe injury risk (OR=0.57, p=0.08) than crashes on weekends. DOP of drivers did not predict a higher severe injury risk to other road users.

Conclusions

Alcohol impairment on driver increases the risk of severe injury to other road users by four times. Road safety education campaign should stress on this adverse impact of drink driving on innocent people.

Bicycle-Related Crashes in Hong Kong: Is it Possible to Reduce Mortality and Severe Injury in the Metropolitan Area?

Background

Cycling is not the primary mode of commuter transport in Hong Kong, yet cyclists are exposed to a high risk of injury and fatality in road crashes. It is essential to identify the significant factors contributing to severe injury among cyclists in Hong Kong.

Aim

To evaluate the effects of significant factors, including demographics, temporal distribution, cyclist behavior, road conditions, and weather, on the risk of severe and life-threatening injury among cyclists in road crashes in Hong Kong.

Method

The study was nested on a database known as Road Casualty Information System (RoCIS) which is a linked database between police traffic accident investigations reports and hospital injury records. A total of 682 victims were identified during the study period from 1 January 2004 to 31 December 2006. In particular, injured body part, demographics, helmet use, alcohol intoxication, weather conditions, road type and geometry, and collision characteristics of 682 trauma patients were the attributing variables of concern. The primary outcome measure was the injury severity of trauma patients which was classified into three levels: slight injury [Injury severity Scale (ISS) </=8], severe injury (ISS >/=9), and life-threatening injury (ISS >/=25). A multinomial logit regression model was established to evaluate the significance of factors contributing to severe and life-threatening injuries among cyclists in road crashes.

Results

The results indicated that middle-aged and elderly (35-54, RRR=2.48; and 55 or above, RRR=4.39) casualties and favourable weather conditions (2.56) significantly increased the risk of severe injury among cyclists. The presence of severe head injury (RRR=509.24), severe trunk injury (RRR=79.24), and the involvement of motor vehicles (RRR=27.18) substantially increased the risk of life-threatening injury to cyclists.

Conclusions

Middle-aged casualties, the presence of head injuries, and the involvement of motor vehicles all increase the risk of more severe injury in bicycle-related crashes. Safety education and countermeasures should target at middle-aged and elderly cyclists and discourage cycling on the motorway.

Protective Effect of Unacylated Ghrelin on Compression-Induced Skeletal Muscle Injury Mediated by SIRT1-Signaling

Unacylated ghrelin, the predominant form of circulating ghrelin, protects myotubes from cell death, which is a known attribute of pressure ulcers. In this study, we investigated whether unacylated ghrelin protects skeletal muscle from pressure-induced deep tissue injury by abolishing necroptosis and apoptosis signaling and whether these effects were mediated by SIRT1 pathway. Fifteen adult Sprague Dawley rats were assigned to receive saline or unacylated ghrelin with or without EX527 (a SIRT1 inhibitor). Animals underwent two 6-h compression cycles with 100 mmHg static pressure applied over the mid-tibialis region of the right limb whereas the left uncompressed limb served as the intra-animal control. Muscle tissues underneath the compression region, and at the similar region of the opposite uncompressed limb, were collected for analysis. Unacylated ghrelin attenuated the compression-induced muscle pathohistological alterations including rounding contour of myofibers, extensive nucleus accumulation in the interstitial space, and increased interstitial space. Unacylated ghrelin abolished the increase in necroptosis proteins including RIP1 and RIP3 and attenuated the elevation of apoptotic proteins including p53, Bax, and AIF in the compressed muscle. Furthermore, unacylated ghrelin opposed the compression-induced phosphorylation and acetylation of p65 subunit of NF-kB. The anti-apoptotic effect of unacylated ghrelin was shown by a decrease in apoptotic DNA fragmentation and terminal dUTP nick-end labeling index in the compressed muscle. The protective effects of unacylated ghrelin vanished when co-treated with EX527. Our findings demonstrated that unacylated ghrelin protected skeletal muscle from compression-induced injury. The myoprotective effects of unacylated ghrelin on pressure-induced tissue injury were associated with SIRT1 signaling.