Judith Adams

Cohort Profile: Updating the cohort profile for the MRC National Survey of Health and Development: a new clinic-based data collection for ageing research

MRC Unit for Lifelong Health and Ageing, Research Department of Epidemiology and Public Health, University College London, London, UK, Clinical Radiology, Manchester Royal Infirmary, Oxford Road, Manchester, UK, Vascular Physiology Unit, Institute of Child Health, University College London, London, UK, MRC Epidemiology Unit, Cambridge, UK, Cardiovacular Institute, Sahlgrenska University Hospital, Göteborg, Sweden, Wellcome Trust Clinical Research Facility Manchester, Manchester, UK, International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London, London, UK, Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK, Department of Echocardiography, The Heart Hospital, London, UK and MRC Human Nutrition Research, Cambridge, UK

A randomised controlled trial of standing programme on bone mineral density in non-ambulant children with cerebral palsy

Background: Severely disabled children with cerebral palsy (CP) are prone to low trauma fractures, which are associated with reduced bone mineral density. Aims: To determine whether participation in 50% longer periods of standing (in either upright or semi-prone standing frames) would lead to an increase in the vertebral and proximal tibial volumetric trabecular bone mineral density (vTBMD) of non-ambulant children with CP. Methods: A heterogeneous group of 26 pre-pubertal children with CP (14 boys, 12 girls; age 4.3–10.8 years) participated in this randomised controlled trial. Subjects were matched into pairs using baseline vertebral vTBMD standard deviation scores. Children within the pairs were randomly allocated to either intervention (50% increase in the regular standing duration) or control (no increase in the regular standing duration) groups. Pre- and post-trial vertebral and proximal tibial vTBMD was measured by quantitative computed tomography (QCT). Results: The median standing duration was 80.5% (9.5–102%) and 140.6% (108.7–152.2%) of the baseline standing duration in the control group and intervention group respectively. The mean vertebral vTBMD in the intervention group showed an increase of 8.16 mg/cm3 representing a 6% mean increase in vertebral vTBMD. No change was observed in the mean proximal tibial vTBMD. Conclusion: A longer period of standing in non-ambulant children with CP improves vertebral but not proximal tibial vTBMD. Such an intervention might reduce the risk of vertebral fractures but is unlikely to reduce the risk of lower limb fractures in children with CP.

Risk factors, falls, and fracture of the distal forearm in Manchester, UK.

OBJECTIVE: To determine the risk factors associated with fracture of the distal forearm, and to evaluate the influence of falls on these risks. DESIGN: This was a case-control study. SETTING: Manchester, UK. PARTICIPANTS: The cases were 62 white women aged 45-82 years who had sustained a fracture of the distal forearm and had attended local hospitals. Two control groups were studied - 50 women who had fallen onto the hand but had not sustained a fracture (recruited from the same source as those with fracture) and 116 women randomly selected from primary care age and sex registers in the catchment area of the hospitals. Both cases and controls were sent a letter inviting them to take part in the study. Data were collected by questionnaire completed by an interviewer. MAIN RESULTS: Compared with the population control group, those with fracture were more likely to walk at a brisk pace (odds ratio (OR) = 3.5; 95% confidence interval (CI) 1.3, 9.6) though they had undertaken less physical activity at home or work on a daily basis throughout life (OR = 0.4; 95% CI 0.2, 0.9). The risk associated with brisk walking was less marked when the cases were compared with fall controls. Other lifestyle factors including calcium intake, smoking, and alcohol consumption were not associated with fracture. Analysis of gynaecological and hormonal factors suggested that compared with population controls, those with fracture of the distal forearm had had fewer fertile years (OR = 0.4; 95% CI 0.1, 0.9) and were less likely to have used oral contraceptives (OR = 0.3; 95% CI 0.1, 0.9). CONCLUSIONS: The data highlight the need for caution when advising middle aged and elderly subjects about exercise. Such advice should be combined with practical information about the prevention of falls. Hormonal factors seem to be additional determinants of fracture. Other lifestyle interventions seem unlikely to play an important part in preventing distal forearm fracture.

Mobility status and bone density in cerebral palsy.

The spinal bone mineral density (SBMD) and calcaneal broadband ultrasound attenuation (BUA) was measured in 27 children with cerebral palsy. They were categorised into four mobility groups: mobile with an abnormal gait, mobile with assistance, non-mobile but weight bearing, non-mobile or weight bearing. Mean SD scores for BUA and SBMD differed among mobility groups (analysis of variance, p < 0.001 and p = 0.078, respectively).

UK reference data for the Hologic QDR Discovery dual-energy x ray absorptiometry scanner in healthy children and young adults aged 6–17 years

Background: The use and correct interpretation of bone densitometry measurements in paediatric patients relies on the availability of appropriate reference data. Ideally, such data should be matched for sex, chronological age, height, weight, pubertal development and ethnicity. Aim: To provide UK-specific reference data for the Hologic QDR Discovery dual-energy x ray absorptiometry (DXA) scanners. Methods: Healthy, Caucasian children aged 5–18 years were recruited from local schools, colleges, general practitioner surgeries and staff from the University of Manchester, Manchester, UK. Suitable participants had DXA measurements taken of the lumbar spine, hip and total body. Sex-specific reference centile curves for bone mineral apparent density (BMAD; spine and femoral neck) are provided, using the approach suggested by Mølgaard et al. to interpret the scans. LMS (λ, μ, ς) tables for calculation of individual standard deviation scores (SDSs) were produced; a weblink is provided to these tables to allow calculation of an individual child’s SDSs. Results: The total study population consisted of 442 participants (239 male). The total numbers of scans available for analysis were 431 of the lumbar spine, 426 of the total body and 393 of the proximal femur. Data are provided for clinical interpretation of the spine and femoral neck scans based on BMAD (g/cm3), which reduces the size dependence of DXA areal bone mineral density (g/cm2). The spine and total-body data are also presented for interpretation of results using the approach suggested by Mølgaard et al. Conclusions: This article provides the first sex-specific and ethnicity-specific reference databases for UK, which should allow the clinician to assess bone mineral density in paediatric patients, measured by the Hologic QDR Discovery DXA scanner.

Bone status in cystic fibrosis

AIM To investigate bone mineral status of children with cystic fibrosis (CF). METHODS In 29 children with CF and 49 matched controls, bone mineral content (BMC), projected bone area (BA), and areal bone mineral density (BMD) of the whole body, total hip, and lumbar spine (L1–L4) were measured using dual energyx ray absorptiometry. The BMC values at each site were adjusted for BA, height, and weight. At the lumbar spine, the bone mineral apparent density (BMAD) was calculated by dividing the BMC by the estimated volume, derived from BA. Vertebral (T12–L3) trabecular bone mineral density (vTBMD) was measured using quantitative computed tomography in children with CF. Calcaneal broadband ultrasound attenuation (BUA) was measured in CF patients and controls using quantitative ultrasound. The disease severity of CF children was evaluated by the Shwachman–Kulczycki (SK) score. RESULTS The mean BUA, whole body and regional BA, adjusted BMC, and areal BMD of children with CF were not different from those of controls. The mean BMAD of the lumbar spine was reduced in CF patients compared with controls, whereas the mean vTBMD standard deviation scores were significantly higher in CF patients. The median SK score of the CF group was 81 (range 42–100), indicating that as a group our CF patient population had relatively mild disease. CONCLUSION The normal vertebral BMC, decreased BMAD, and higher vTBMD suggests that the vertebral cortical thickness or density might be reduced in CF subjects. The overall bone mineral status of CF children with relatively mild disease was not different from size matched controls.

Vertebral morphometry: semiautomatic determination of detailed shape from dual-energy X-ray absorptiometry images using active appearance models.

Objectives:Manual point placement for vertebral morphometry is time-consuming and imprecise. We evaluated the accuracy of semiautomatic computer determination of the detailed vertebral shape. Materials and Methods:The shape and appearance of vertebrae on 250 lateral dual-energy x-ray absorptiometry (DXA) scans were statistically modeled using a sequence of active appearance models of vertebral triplets. The models were matched to unseen scans given an approximate initial location of the center of each vertebra. The segmentation accuracy was analyzed by fracture grade. Results:Segmentation accuracy comparable to manual precision was obtained in the case of normal vertebrae, but the accuracy decreased with increasing fracture severity. We propose methods for improving the robustness for severe fractures. Conclusion:Vertebral morphometry measurements may be substantially automated even on noisy data with multiple fractures present. The shape and appearance parameters of the models could provide more powerful quantitative classifiers of osteoporotic vertebral fracture.

Quantitative Computer Tomography in Children and Adolescents: The 2013 ISCD Pediatric Official Positions

In 2007, International Society of Clinical Densitometry Pediatric Positions Task Forces reviewed the evidence for the clinical application of peripheral quantitative computed tomography (pQCT) in children and adolescents. At that time, numerous limitations regarding the clinical application of pQCT were identified, although its use as a research modality for investigation of bone strength was highlighted. The present report provides an updated review of evidence for the clinical application of pQCT, as well as additional reviews of whole body QCT scans of the central and peripheral skeletons, and high-resolution pQCT in children. Although these techniques remain in the domain of research, this report summarizes the recent literature and evidence of the clinical applicability and offers general recommendations regarding the use of these modalities in pediatric bone health assessment.

Physical Activity Across Adulthood in Relation to Fat and Lean Body Mass in Early Old Age: Findings From the Medical Research Council National Survey of Health and Development, 1946–2010

Fat and lean body mass have important implications for health and physical functioning in older age, and physical activity is purported to be an important modifiable determinant. However, our evidence-based understanding of its role is limited. We examined the associations of physical activity, assessed both by self-report (using data on leisure time physical activity (LTPA) collected on 4 occasions over a 28-year period) and objectively (using 5-day heart rate and movement monitoring), with fat and lean mass at ages 60–64 years in 1,162 British participants from the Medical Research Council National Survey of Health and Development in 1946–2010. Higher objectively assessed physical activity energy expenditure (PAEE) at ages 60–64 years was associated with lower fat mass and android (abdominal):gynoid (hip) fat ratio (mean differences in fat mass per 1–standard deviation increase in PAEE were −0.79 kg/m1.2 in men (95% confidence interval: −1.08, −0.50) and −1.79 kg/m1.2 (95% confidence interval: −2.15, −1.42) in women). After adjustment for fat mass, higher PAEE was associated with higher appendicular lean mass. Both light and moderate-to-vigorous intensities of activity were associated with fat mass, and the latter was associated with lean mass. More frequent LTPA across adulthood was associated with lower fat mass (in women only) and higher appendicular lean mass (in both sexes, after adjustment for fat mass). These results support the promotion of LTPA across adulthood, as well as both light and moderate-to-vigorous intensities of activity among older adults.

Osteoporosis detection using intraoral densitometry

OBJECTIVES To determine the diagnostic accuracy of mandibular and maxillary bone density in detecting osteoporosis using receiver operating characteristic (ROC) analysis. METHODS 671 women between 45 years and 70 years of age underwent dual energy X-ray absorptiometry (DXA) of the hip and lumbar spine. This was the gold standard for diagnosing osteoporosis. Intraoral radiography of the upper and lower right premolar region was performed, using an aluminium wedge as a densitometric reference. Jaw bone density was determined using dedicated software. Observer differences and ROC curves were analysed. RESULTS For detecting osteoporosis using jaw bone density, the area under the ROC curve (A(z)) was 0.705. For separate analysis of mandibular and maxillary films, sensitivity varied from 33.9% to 38.7% and specificity from 83.5% to 85.3% when using a threshold of 4.3 mm Al equivalent. CONCLUSIONS Density of the premolar region reaches a fair diagnostic accuracy, which might improve when including additional factors in the analysis and refining the densitometric tool.