Alcohol use among Australian parents during the COVID-19 pandemic - April-2020 to May 2021.

AIMS: This study examined the trajectory of alcohol use frequency among parents from April-2020 to May-2021 during the COVID-19 pandemic in the state of Victoria, Australia (who experienced one of the longest lockdowns in the world), compared to parents from the other states of Australia (who experienced relatively fewer restrictions). We further examined the extent to which baseline demographic factors were associated with changes in alcohol use trajectories among parents. METHOD: Data were from the COVID-19 Pandemic Adjustment Survey (2,261 parents of children 0-18 years). Alcohol use frequency was assessed over 13 waves. Baseline demographic predictors included parent gender, age, speaking a language other than English, number of children, partnership status, education, employment, and income. RESULTS: Overall, alcohol trajectories declined over time. Victorian parents, in comparison to parents from other states, reported a smaller reduction in alcohol use frequency across 2020, with a more notable decline during 2021. Female/other gender, speaking a language other than English at home, unemployment, and lower income (Victoria only) were associated with alcohol trajectories of less frequent use, and older age was associated with a trajectory of more frequent use. CONCLUSIONS: Results suggest subtle difference in alcohol trajectories reflecting COVID-19 restrictions, when comparing Victoria and other states in Australia. Socioeconomically advantaged groups were most at risk for elevated trajectories of alcohol use frequency. Population level support may beneficial to reduce drinking behaviours.

A proof-of-concept study applying machine learning methods to putative risk factors for eating disorders: results from the multi-centre European project on healthy eating.

BACKGROUND: Despite a wide range of proposed risk factors and theoretical models, prediction of eating disorder (ED) onset remains poor. This study undertook the first comparison of two machine learning (ML) approaches [penalised logistic regression (LASSO), and prediction rule ensembles (PREs)] to conventional logistic regression (LR) models to enhance prediction of ED onset and differential ED diagnoses from a range of putative risk factors. METHOD: Data were part of a European Project and comprised 1402 participants, 642 ED patients [52% with anorexia nervosa (AN) and 40% with bulimia nervosa (BN)] and 760 controls. The Cross-Cultural Risk Factor Questionnaire, which assesses retrospectively a range of sociocultural and psychological ED risk factors occurring before the age of 12 years (46 predictors in total), was used. RESULTS: All three statistical approaches had satisfactory model accuracy, with an average area under the curve (AUC) of 86% for predicting ED onset and 70% for predicting AN v. BN. Predictive performance was greatest for the two regression methods (LR and LASSO), although the PRE technique relied on fewer predictors with comparable accuracy. The individual risk factors differed depending on the outcome classification (EDs v. non-EDs and AN v. BN). CONCLUSIONS: Even though the conventional LR performed comparably to the ML approaches in terms of predictive accuracy, the ML methods produced more parsimonious predictive models. ML approaches offer a viable way to modify screening practices for ED risk that balance accuracy against participant burden.

Child, parent, and family mental health and functioning in Australia during COVID-19: comparison to pre-pandemic data.

The COVID-19 pandemic presents significant risks to population mental health. Despite evidence of detrimental effects for adults, there has been limited examination of the impact of COVID-19 on parents and children specifically. We aim to examine patterns of parent and child (0-18 years) mental health, parent substance use, couple conflict, parenting practices, and family functioning during COVID-19, compared to pre-pandemic data, and to identify families most at risk of poor outcomes according to pre-existing demographic and individual factors, and COVID-19 stressors. Participants were Australian mothers (81%) and fathers aged 18 years and over who were parents of a child 0-18 years (N = 2365). Parents completed an online self-report survey during 'stage three' COVID-19 restrictions in April 2020. Data were compared to pre-pandemic data from four Australian population-based cohorts. Compared to pre-pandemic estimates, during the pandemic period parents reported higher rates of parent depression, anxiety, and stress (Cohen's d = 0.26-0.81, all p < 0.001), higher parenting irritability (d = 0.17-0.46, all p < 0.001), lower family positive expressiveness (d = - 0.18, p < 0.001), and higher alcohol consumption (22% vs 12% drinking four or more days per week, p < 0.001). In multivariable analyses, we consistently found that younger parent age, increased financial deprivation, pre-existing parent and child physical and mental health conditions, COVID-19 psychological and environmental stressors, and housing dissatisfaction were associated with worse parent and child functioning and more strained family relationships. Our data suggest wide-ranging, detrimental family impacts associated with the COVID-19 pandemic; and support policy actions to assist families with financial supports, leave entitlements, and social housing.

Feasibility and preliminary efficacy of the LEAD trial: a cluster randomized controlled lifestyle intervention to improve hippocampal volume in older adults at-risk for dementia.

BACKGROUND: Healthy diet and exercise are associated with reduced risk of dementia in older adults. The impact of diet and exercise interventions on brain health is less consistent, especially with dietary interventions which rely on varying approaches. Our objective was to evaluate the feasibility and preliminary efficacy of a 6-month intervention combining exercise with a novel dietary counseling approach to improve hippocampal volume among older adults at-risk for dementia. METHODS: Participants with vascular risk factors and subjective cognitive decline or early mild cognitive impairment were cluster randomized in groups of 3-4 to the diet intervention (DIET) or control education (ED) group. All participants engaged in 1 h of supervised exercise per week and additional exercise at home. DIET involved 1 h per week of group-based dietary counseling comprising education, goal setting, and strategy training. ED involved 1 h per week of group-based brain health education classes. Our primary outcome was change in hippocampal volume from baseline to 6 months. Secondary outcomes included changes in cognitive function, blood biomarkers, diet, and fitness. Recruitment challenges and early discontinuation of the trial due to COVID-19 necessitated a revised focus on feasibility and preliminary efficacy. RESULTS: Of 190 older adults contacted, 14 (7%) were eligible and enrolled, constituting 21% of our recruitment target. All participants completed the intervention and attended 90% of exercise and DIET/ED sessions on average. All 6-month assessments prior to COVID-19 were completed but disruptions to in-person testing resulted in incomplete data collection. No serious adverse events occurred and all participants expressed positive feedback about the study. Preliminary findings did not identify any significant changes in hippocampal volume; however, substantial improvements in diet and HbA1c were observed with DIET compared to ED (d = 1.75 and 1.07, respectively). CONCLUSIONS: High adherence and retention rates were observed among participants and preliminary findings illustrate improvements in diet quality and HbA1c. These results indicate that a larger trial is feasible if difficulties surrounding recruitment can be mitigated. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03056508 .

From adolescence to parenthood: a multi-decade study of preconception mental health problems and postpartum parent-infant bonds.

PURPOSE: To examine associations between anxiety and depressive symptoms across adolescence and young adulthood with subsequent maternal- and paternal-infant bonding at 1 year postpartum. METHODS: The data were from a prospective, intergenerational cohort study. Participants (381 mothers of 648 infants; 277 fathers of 421 infants) self-reported depression and anxiety at three adolescent waves (ages 13, 15 and 17 years) and three young adult waves (ages 19, 23 and 27 years). Subsequent parent-infant bonds with infants were reported at 1 year postpartum (parent age 29-35 years). Generalised estimating equations (GEE) separately assessed associations for mothers and fathers. RESULTS: Mean postpartum bonding scores were approximately half a standard deviation lower in parents with a history of persistent adolescent and young adult depressive symptoms (maternal ßadj = - 0.45, 95% CI - 0.69, - 0.21; paternal ßadj = - 0.55, 95% CI - 0.90, 0.20) or anxiety (maternal ßadj = - 0.42, 95% CI - 0.66, - 0.18; paternal ßadj = - 0.49, 95% CI - 0.95, 0.03). Associations were still mostly evident, but attenuated after further adjustment for postpartum mental health concurrent with measurement of bonding. CONCLUSIONS: Persistent symptoms of depression or anxiety spanning adolescence and young adulthood predict poorer emotional bonding with infants 1-year postbirth for both mothers and fathers.

The Identification of Low-risk Gambling Limits for Specific Gambling Activities.

An emerging literature has identified optimal low-risk gambling limits in an effort to reduce gambling-related harm. Concerns have, however, been raised about the construction of aggregate low-risk limits that are applied to all gambling activities and there is support from gambling experts and the general public in Australia for the identification of low-risk limits for specific gambling activities. The study's aim was to identify and evaluate a set of empirically-based activity-specific limits (gambling frequency, gambling expenditure, gambling expenditure as a proportion of gross personal income, session expenditure, session duration) in a secondary analysis of Social and Economic Impact Studies of Gambling in Tasmania and the 2014 Survey on Gambling, Health and Wellbeing in the ACT. Balancing sensitivity and specificity, limits were identified for all gambling activities: EGMs (10 times per year, AUD$300/year, 0.63-1.04% of personal income, AUD$35 per session, 40 min/session), horse/dog racing (0.55% of personal income), instant scratch tickets (AUD$45/year), lotteries (0.45% of personal income), keno (4-13 times/year, AUD$45-$160/year), casino table games (AUD$345/year, 0.36-0.76% of personal income), bingo (AUD$150/year, 0.49% of personal income, AUD$17/session, 90 min/session), and sports/other event betting (14 times/year, AUD$400/year, 0.55-0.86% of personal income). These limits were exceeded by one-quarter to one-half of gamblers on these specific activities and were generally good predictors of gambling-related harm in subgroups of gamblers participating in these gambling activities and in the overall gambling sample. The limits provide gamblers, regulators, prevention workers, and researchers with simple rules of thumb in prevention efforts to reduce gambling-related harm in specific contexts.

Psychosocial predictors of binge-drinking residual harm in adolescence and young adulthood: Findings from the Australian Temperament Project.

AIMS: We examine the extent to which adolescent and young adult psychosocial factors are associated with variation in the experience of common types of harm (e.g., injuries, violence, sexual regrets) with respect to binge-drinking frequency - termed residual harm. METHODS: Data were from the Australian Temperament Project, a population-based cohort study that has followed a sample of young Australians from infancy to adulthood since 1983. The current sample comprised 1,081 (565 women). Residual harm was operationalised by saving residuals from models regressing number of alcohol harms onto binge-drinking frequency at each of 5 waves, two in adolescence (15-16 and 17-18 years) and three in young adulthood (19-20, 23-24, and 27-28 years). Psychosocial factors (mental health, social skills, quality of parent and peer relationships) were assessed prior to binge drinking in early adolescence (13-14 years) and then again in young adulthood (19-20 years). RESULTS: Adolescent predictors of decreased residual harm were lower depressive symptoms, and higher cooperation, self-control, and peer and parent attachment. Young adult predictors of decreased residual harm were lower depressive, anxiety, and stress symptoms and peer and parent negative appraisal, and higher responsibility, and peer and parent emotional support. Associations were evident in males and females, although the strength of some associations diminished with age. CONCLUSIONS: Adolescents and young adults with better mental health, social skills, and relationship quality experienced less harm with respect to their binge-drinking frequency. Future research should examine the potential of investment in strength-based interventions for young people.

Exploring a causal model in observational cohort data: The role of parents and peers in shaping substance use trajectories.

AIMS: To explore the process of applying counterfactual thinking in examining causal determinants of substance use trajectories in observational cohort data. Specifically, we examine the extent to which quality of the parent-adolescent relationship and affiliations with deviant peers are causally related to trajectories of alcohol, tobacco, and cannabis use across adolescence and into young adulthood. METHODS: Data were drawn from the Australian Temperament Project, a population-based cohort study that has followed a sample of young Australians from infancy to adulthood since 1983. Parent-adolescent relationship quality and deviant peer affiliations were assessed at age 13-14 years. Latent curve models were fitted for past month alcohol, tobacco, and cannabis use (n = 1590) from age 15-16 to 27-28 years (5 waves). Confounding factors were selected in line with the counterfactual framework. RESULTS: Following confounder adjustment, higher quality parent-adolescent relationships were associated with lower baseline cannabis use, but not alcohol or tobacco use trajectories. In contrast, affiliations with deviant peers were associated with higher baseline binge drinking, tobacco, and cannabis use, and an earlier peak in the cannabis use trajectory. CONCLUSIONS: Despite careful application of the counterfactual framework, interpretation of associations as causal is not without limitations. Nevertheless, findings suggested causal effects of both parent-adolescent relationships and deviant peer affiliations on the trajectory of substance use. Causal effects were more pervasive (i.e., more substance types) and protracted for deviant peer affiliations. The exploration of causal relationships in observational cohort data is encouraged, when relevant limitations are transparently acknowledged.

Enhancing the utility of the problem gambling severity index in clinical settings: Identifying refined categories within the problem gambling category.

BACKGROUND: The Problem Gambling Severity Index (PGSI) was intended for use in epidemiological research with gamblers across the continuum of risk. Its utility within clinical settings, where the majority of clients are problem gamblers, has been brought into question. AIMS: (1) Identify refined categories for the problem gambling category of the PGSI in help-seeking gamblers; (2) Validate these categories using the Gambling Symptom Assessment Scale (G-SAS); (3) Explore the relationship of these categories with indices of gambling and help-seeking behaviour. METHODS: Secondary data analysis of help-seeking problem gamblers from the Australian online gambling counselling/support service (Gambling Help Online [GHO]) from October 2012 to December 2015 (n = 5,881) and trial data evaluating an Australian online self-directed program for gambling (GamblingLess; n = 198). Both datasets included the PGSI, gambling frequency and expenditure. The GamblingLess dataset also included the G-SAS and help-seeking behaviour. RESULTS: A Latent Class Analysis, using GHO data, identified a 2-class solution. Multiple analytical methods identified a cut-off value of ≥ 19 distinguishing this 2-class solution (low problem severity: Median = 16; high problem severity: Median = 23). High problem severity gamblers had increased odds of being categorised in the higher GSAS category, greater gambling expenditure and having sought face-to-face support. The refined categories were not associated with gambling frequency, distance-based or self-directed help-seeking. CONCLUSION: These findings are consistent with a stepped-care approach, whereby individuals with higher severity may be better suited to more intensive interventions and individuals with lower severity could commence with less intensive interventions and step-up to intensive interventions.

A comparison of longitudinal modelling approaches: Alcohol and cannabis use from adolescence to young adulthood.

BACKGROUND: Modelling trajectories of substance use over time is complex and requires judicious choices from a number of modelling approaches. In this study we examine the relative strengths and weakness of latent curve models (LCM), growth mixture modelling (GMM), and latent class growth analysis (LCGA). DESIGN: Data were drawn from the Australian Temperament Project, a 36-year-old community-based longitudinal study that has followed a sample of young Australians from infancy to adulthood across 16 waves of follow-up since 1983. Models were fitted on past month alcohol use (n = 1468) and cannabis use (n = 549) across six waves of data collected from age 13-14 to 27-28 years. FINDINGS: Of the three model types, GMMs were the best fit. However, these models were limited given the variance of numerous growth parameters had to be constrained to zero. Additionally, both the GMM and LCGA solutions had low entropy. The negative binomial LCMs provided a relatively well-fitting solution with fewer drawbacks in terms of growth parameter estimation and entropy issues. In all cases, model fit was enhanced when using a negative binomial distribution. CONCLUSIONS: Substance use researchers would benefit from adopting a complimentary framework by exploring both LCMs and mixture approaches, in light of the relative strengths and weaknesses as identified. Additionally, the distribution of data should inform modelling decisions.

Rare susceptibility variants for bipolar disorder suggest a role for G protein-coupled receptors.

Bipolar disorder (BD) is a prevalent mood disorder that tends to cluster in families. Despite high heritability estimates, few genetic susceptibility factors have been identified over decades of genetic research. One possible interpretation for the shortcomings of previous studies to detect causative genes is that BD is caused by highly penetrant rare variants in many genes. We explored this hypothesis by sequencing the exomes of affected individuals from 40 well-characterized multiplex families. We identified rare variants segregating with affected status in many interesting genes, and found an enrichment of deleterious variants in G protein-coupled receptor (GPCR) family genes, which are important drug targets. Furthermore, we showed targeted downstream GPCR dysregulation for some of the variants that may contribute to disease pathology. Particularly interesting was the finding of a rare and functionally relevant nonsense mutation in the corticotropin-releasing hormone receptor 2 (CRHR2) gene that tracked with affected status in one family. By focusing on rare variants in informative families, we identified key biochemical pathways likely implicated in this complex disorder.

Stability of the human sperm DNA methylome to folic acid fortification and short-term supplementation.

STUDY QUESTION: Do short-term and long-term exposures to low-dose folic acid supplementation alter DNA methylation in sperm? SUMMARY ANSWER: No alterations in sperm DNA methylation patterns were found following the administration of low-dose folic acid supplements of 400 µg/day for 90 days (short-term exposure) or when pre-fortification of food with folic acid and post-fortification sperm samples (long-term exposure) were compared. WHAT IS KNOWN ALREADY: Excess dietary folate may be detrimental to health and DNA methylation profiles due to folate's role in one-carbon metabolism and the formation of S-adenosyl methionine, the universal methyl donor. DNA methylation patterns are established in developing male germ cells and have been suggested to be affected by high-dose (5 mg/day) folic acid supplementation. STUDY DESIGN, SIZE, DURATION: This is a control versus treatment study where genome-wide sperm DNA methylation patterns were examined prior to fortification of food (1996-1997) in men with no history of infertility at baseline and following 90-day exposure to placebo (n = 9) or supplement containing 400 µg folic acid/day (n = 10). Additionally, pre-fortification sperm DNA methylation profiles (n = 19) were compared with those of a group of post-fortification (post-2004) men (n = 8) who had been exposed for several years to dietary folic acid fortification. PARTICIPANTS/MATERIALS, SETTING, METHODS: Blood and seminal plasma folate levels were measured in participants before and following the 90-day treatment with placebo or supplement. Sperm DNA methylation was assessed using the whole-genome and genome-wide techniques, MassArray epityper, restriction landmark genomic scanning, methyl-CpG immunoprecipitation and Illumina HumanMethylation450 Bead Array. MAIN RESULTS AND THE ROLE OF CHANCE: Following treatment, supplemented individuals had significantly higher levels of blood and seminal plasma folates compared to placebo. Initial first-generation genome-wide analyses of sperm DNA methylation showed little evidence of changes when comparing pre- and post-treatment samples. With Illumina HumanMethylation450 BeadChip arrays, no significant changes were observed in individual probes following low-level supplementation; when compared with those of the post-fortification cohort, there were also few differences in methylation despite exposure to years of fortified foods. LARGE SCALE DATA: Illumina HumanMethylation450 BeadChip data from this study have been submitted to the NCBI Gene Expression Omnibus under the accession number GSE89781. LIMITATIONS, REASONS FOR CAUTION: This study was limited to the number of participants available in each cohort, in particular those who were not exposed to early (pre-1998) fortification of food with folic acid. While genome-wide DNA methylation was assessed with several techniques that targeted genic and CpG-rich regions, intergenic regions were less well interrogated. WIDER IMPLICATIONS OF THE FINDINGS: Overall, our findings provide evidence that short-term exposure to low-dose folic acid supplements of 400 µg/day, over a period of 3 months, a duration of time that might occur during infertility treatments, has no major impact on the sperm DNA methylome. STUDY FUNDING/COMPETING INTERESTS: This work was supported by a grant to J.M.T. from the Canadian Institutes of Health Research (CIHR: MOP-89944). The authors have no conflicts of interest to declare.

Early risk and protective factors for problem gambling: A systematic review and meta-analysis of longitudinal studies.

This systematic review aimed to identify early risk and protective factors (in childhood, adolescence or young adulthood) longitudinally associated with the subsequent development of gambling problems. A systematic search of peer-reviewed and grey literature from 1990 to 2015 identified 15 studies published in 23 articles. Meta-analyses quantified the effect size of 13 individual risk factors (alcohol use frequency, antisocial behaviours, depression, male gender, cannabis use, illicit drug use, impulsivity, number of gambling activities, problem gambling severity, sensation seeking, tobacco use, violence, undercontrolled temperament), one relationship risk factor (peer antisocial behaviours), one community risk factor (poor academic performance), one individual protective factor (socio-economic status) and two relationship protective factors (parent supervision, social problems). Effect sizes were on average small to medium and sensitivity analyses revealed that the results were generally robust to the quality of methodological approaches of the included articles. These findings highlight the need for global prevention efforts that reduce risk factors and screen young people with high-risk profiles. There is insufficient investigation of protective factors to adequately guide prevention initiatives. Future longitudinal research is required to identify additional risk and protective factors associated with problem gambling, particularly within the relationship, community, and societal levels of the socio-ecological model.

Towards new material biomarkers for fracture risk.

Osteoporosis is a prevalent bone condition, characterised by low bone mass and increased fracture risk. Currently, the gold standard for identifying osteoporosis and increased fracture risk is through quantification of bone mineral density (BMD) using dual energy X-ray absorption (DEXA). However, the risk of osteoporotic fracture is determined collectively by bone mass, architecture and physicochemistry of the mineral composite building blocks. Thus DEXA scans alone inevitably fail to fully discriminate individuals who will suffer a fragility fracture. This study examines trabecular bone at both ultrastructure and microarchitectural levels to provide a detailed material view of bone, and therefore provides a more comprehensive explanation of osteoporotic fracture risk. Physicochemical characterisation obtained through X-ray diffraction and infrared analysis indicated significant differences in apatite crystal chemistry and nanostructure between fracture and non-fracture groups. Further, this study, through considering the potential correlations between the chemical biomarkers and microarchitectural properties of trabecular bone, has investigated the relationship between bone mechanical properties (e.g. fragility) and physicochemical material features.

Classification of fracture and non-fracture groups by analysis of coherent X-ray scatter.

Osteoporotic fractures present a significant social and economic burden, which is set to rise commensurately with the aging population. Greater understanding of the physicochemical differences between osteoporotic and normal conditions will facilitate the development of diagnostic technologies with increased performance and treatments with increased efficacy. Using coherent X-ray scattering we have evaluated a population of 108 ex vivo human bone samples comprised of non-fracture and fracture groups. Principal component fed linear discriminant analysis was used to develop a classification model to discern each condition resulting in a sensitivity and specificity of 93% and 91%, respectively. Evaluating the coherent X-ray scatter differences from each condition supports the hypothesis that a causal physicochemical change has occurred in the fracture group. This work is a critical step along the path towards developing an in vivo diagnostic tool for fracture risk prediction.

The aetiology of rickets-like lower limb deformities in Malawian children.

UNLABELLED: Debilitating rickets-like lower limb deformities are common in children throughout the world, particularly in Malawi, Africa where the causes are unknown. We have identified that Blount disease and calcium deficiency rickets are the likely causes of these deformities and propose calcium supplementation as a potential treatment of Malawian rickets. INTRODUCTION: Surgical correction of rickets-like lower limb deformities is the most common paediatric operation performed at Beit Cure Orthopaedic Hospital, Malawi. The aim of this study was to investigate the aetiology of these deformities. METHODS: Children with a tibio-femoral angle of deformity >20° were enrolled (n = 42, 3.0-15.0 years). Anthropometric and early life and well-being data were collected. Early morning serum and urine samples were collected on the morning of the operation for markers of calcium and phosphate homeostasis. Knee radiographs were obtained, and the children were diagnosed with either Blount (BD, n = 22) or evidence of rickets disease (RD, n = 20). As BD is a mechanical rather than metabolic disease, BD were assumed to be biochemically representative of the local population and thus used as a local reference for RD. RESULTS: There were no differences in anthropometry or early life experiences between BD and RD. Parathyroid hormone (PTH), 1,25-dihydroxyvitamin D, total alkaline phosphatase and urinary phosphate were significantly higher and serum phosphate, 25-hydroxyvitamin D (25OHD) and tubular maximal reabsorption of phosphate significantly lower in RD than BD. There was no difference in serum calcium, fibroblast growth factor 23 or markers of iron status between groups. All children had 25OHD > 25 nmol/L. CONCLUSIONS: Vitamin D deficiency is not implicated in the aetiology of RD or BD in Malawian children. The cause of RD in Malawi is likely to be dietary calcium deficiency leading to elevated PTH resulting in increased losses of phosphate from the bone and glomerular filtrate. The causes of BD remain unclear; there was no evidence in support of previously suggested risk factors such as being overweight or starting to walk early. Prior to surgical intervention, supplementation with calcium should be considered for children with RD.

X-ray diffraction from bone employing annular and semi-annular beams.

There is a compelling need for accurate, low cost diagnostics to identify osteo-tissues that are associated with a high risk of fracture within an individual. To satisfy this requirement the quantification of bone characteristics such as 'bone quality' need to exceed that provided currently by densitometry. Bone mineral chemistry and microstructure can be determined from coherent x-ray scatter signatures of bone specimens. Therefore, if these signatures can be measured, in vivo, to an appropriate accuracy it should be possible by extending terms within a fracture risk model to improve fracture risk prediction.In this preliminary study we present an examination of a new x-ray diffraction technique that employs hollow annular and semi-annular beams to measure aspects of 'bone quality'. We present diffractograms obtained with our approach from ex vivo bone specimens at Mo Kα and W Kα energies. Primary data is parameterized to provide estimates of bone characteristics and to indicate the precision with which these can be determined.

Energy-dispersive X-ray diffraction using an annular beam.

We demonstrate material phase identification by measuring polychromatic diffraction spots from samples at least 20 mm in diameter and up to 10 mm thick with an energy resolving point detector. Within our method an annular X-ray beam in the form of a conical shell is incident with its symmetry axis normal to an extended polycrystalline sample. The detector is configured to receive diffracted flux transmitted through the sample and is positioned on the symmetry axis of the annular beam. We present the experiment data from a range of different materials and demonstrate the acquisition of useful data with sub-second collection times of 0.5 s; equating to 0.15 mAs. Our technique should be highly relevant in fields that demand rapid analytical methods such as medicine, security screening and non-destructive testing.