Melbourne School of Population and Global Health - Research Publications
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ItemManaging risks associated with environmental water delivery: a case study of the Goulburn River, Australia(ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2024-01-01)
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ItemTrauma-Informed Primary Healthcare for Parents: Multidisciplinary Experiences in Rural Service Implementation(ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2023-01-01)
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ItemAccuracy of Local Authority Population Forecasts Produced by a New Minimal Data Model: A Case Study of England(SPRINGER, 2023-12)Abstract The preparation of forecasts for small and local area populations involves many challenges. Standard cohort-component models are problematic because of small numbers, which make estimation of rates unreliable. Because of this, the Synthetic Migration Population Projection (SYMPOPP) model was designed to forecast local populations without need for detailed area-specific information. This model had been used successfully for small area forecasts in Australia. The objective of the paper is to assess its performance when applied to local areas in England. The model uses a bi-regional structure based on a movement population account. Sub-models of total population change are employed to control future change. Fertility, mortality and migration rates are borrowed from national statistics, constrained to small area indicators. The model uses an Excel workbook with VBA routines and is relatively easy and quick to use. Model inputs were calibrated for 2006–2011 and used to forecast for 2011–2021. Results were tested against the census-based 2021 mid-year populations. A new error statistic, Age Structure Error, was used to evaluate Basic and Refined model versions against official projections. The two versions of SYMPOPP posted lower errors. The simple models had fewer areas with errors of 10% or more (12.3–12.6%) compared with the official projections (14.5% of areas). Investigation revealed that these errors occurred in local authorities with high military, student, prison, or ethnic minority populations, influenced by factors not captured in a projection model for the general population.
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ItemDisability and loneliness in the United Kingdom: cross-sectional and longitudinal analyses of trends and transitions(BMC, 2023-12-19)BACKGROUND: Loneliness can have a detrimental impact on health, yet little is known about the association between disability and loneliness. METHODS: Secondary analysis of three waves of data collected between 2017 and 2020 by the UK's annual household panel study, Understanding Society. Direct age-standardisation was used to compare the prevalence of loneliness at each wave and the persistence of loneliness across all three waves for participants with/without disabilities aged 16-65 years. Transitional probabilities for the stability of loneliness, the stability of non-loneliness, the onset of loneliness and the offset of loneliness between consecutive waves were also estimated. RESULTS: At each wave, the prevalence of loneliness was significantly higher among respondents with disabilities than respondents without disabilities; these inequalities persisted with no evidence of change over time. The prevalence of persistent loneliness was 46% for respondents with disabilities compared with 22% for respondents without disabilities. Risk factors for the likelihood of persistent loneliness included disability, financial stress, not living as a couple, living in rented accommodation, being female and not being employed. The probability of the onset and stability of loneliness between successive waves were markedly higher for people with disabilities compared with people without disabilities. CONCLUSION: Adults with disabilities were more likely to experience loneliness, become lonely and remain lonely over time than their peers. Policies and interventions aimed at reducing loneliness should ensure that they are accessible and effective for people with disabilities. Further research is needed to explore the health outcomes of persistent loneliness among people with/without disabilities.
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ItemComing of Age on the Margins: A Life Course Perspective on the Time Use of Australian Adolescents with Disabilities(OXFORD UNIV PRESS INC, )Abstract People with disabilities experience persistent, multifaceted disadvantage across the life course. The origins of life course disadvantage among people with disabilities may stem, in part, from exclusion during developmentally sensitive periods in childhood. Time use among adolescents represents a potentially important mechanism implicated in the emergence of disability-related disadvantage, but previous research has largely neglected the time use of school age adolescents with disabilities. Utilizing nationally representative time diary data, this study investigated disability-related differences in adolescents’ time use, and how these gaps vary by sex and age. Results indicated that disability-related differences in time use are widespread and substantial in magnitude. Adolescents with disabilities spend more time in screen-based leisure, alone, and with mothers, and less time in educational activities than non-disabled adolescents. Boys with disabilities additionally spend less time in structured leisure and with peers than non-disabled boys. Differences in time alone, with peers, and in screen-based leisure increase in magnitude at older ages. We conclude that differential time use in adolescence may contribute to multiple persistent disadvantages experienced by people with disabilities over the life course.
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ItemSmall-scale mutations are infrequent as mechanisms of resistance in post-PARP inhibitor tumour samples in high grade serous ovarian cancer(NATURE PORTFOLIO, 2023-12-10)While the introduction of poly-(ADP)-ribose polymerase (PARP) inhibitors in homologous recombination DNA repair (HR) deficient high grade serous ovarian, fallopian tube and primary peritoneal cancers (HGSC) has improved patient survival, resistance to PARP inhibitors frequently occurs. Preclinical and translational studies have identified multiple mechanisms of resistance; here we examined tumour samples collected from 26 women following treatment with PARP inhibitors as part of standard of care or their enrolment in clinical trials. Twenty-one had a germline or somatic BRCA1/2 mutation. We performed targeted sequencing of 63 genes involved in DNA repair processes or implicated in ovarian cancer resistance. We found that just three individuals had a small-scale mutation as a definitive resistance mechanism detected, having reversion mutations, while six had potential mechanisms of resistance detected, with alterations related to BRCA1 function and mutations in SHLD2. This study indicates that mutations in genes related to DNA repair are detected in a minority of HGSC patients as genetic mechanisms of resistance. Future research into resistance in HGSC should focus on copy number, transcriptional and epigenetic aberrations, and the contribution of the tumour microenvironment.
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ItemEstimated dietary intake of polyphenols from cereal foods and associated lifestyle and demographic factors in the Melbourne Collaborative Cohort Study.(Nature Portfolio, 2023-05-26)Cereal foods are consumed globally and are important sources of polyphenols with potential health benefits, yet dietary intakes are unclear. We aimed to calculate the dietary intakes of polyphenols from cereal foods in the Melbourne Collaborative Cohort Study (MCCS), and describe intakes by demographic and lifestyle factors. We estimated intakes of alkylresorcinols, lignans and phenolic acids in n = 39,892 eligible MCCS participants, using baseline dietary data (1990-1994) from a 121-item FFQ containing 17 cereal foods, matched to a polyphenol database developed from published literature and Phenol-Explorer Database. Intakes were estimated within groups according to lifestyle and demographic factors. The median (25th-75th percentile) intake of total polyphenols from cereal foods was 86.9 mg/day (51.4-155.8). The most consumed compounds were phenolic acids, with a median intake of 67.1 mg (39.5-118.8), followed by alkylresorcinols of 19.7 mg (10.8-34.6). Lignans made the smallest contribution of 0.50 mg (0.13-0.87). Higher polyphenol intakes were associated with higher relative socio-economic advantage and prudent lifestyles, including lower body mass index (BMI), non-smoking and higher physical activity scores. The findings based on polyphenol data specifically matched to the FFQ provide new information on intakes of cereal polyphenols, and how they might vary according to lifestyle and demographic factors.
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ItemFamilial confounding of internalising symptoms and obesity in adolescents and young adults; a co-twin analysis(SPRINGERNATURE, 2024-02-15)BACKGROUND: Obesity and internalising disorders, including depression and anxiety, often co-occur. There is evidence that familial confounding contributes to the co-occurrence of internalising disorders and obesity in adults. However, its impact on this association among young people is unclear. Our study investigated the extent to which familial factors confound the association between internalising disorders and obesity in adolescents and young adults. SUBJECTS/METHODS: We used a matched co-twin design to investigate the impact of confounding by familial factors on associations between internalising symptoms and obesity in a sample of 4018 twins aged 16 to 27 years. RESULTS: High levels of internalising symptoms compared to low levels increased the odds of obesity for the whole cohort (adjusted odds ratio [AOR] = 3.1, 95% confidence interval [CI]: 1.5, 6.8), and in females (AOR = 4.1, 95% CI 1.5, 11.1), but not in males (AOR = 2.8 95% CI 0.8, 10.0). We found evidence that internalising symptoms were associated with an increased between-pair odds of obesity (AOR 6.2, 95% CI 1.7, 22.8), using the paired analysis but not using a within-pair association, which controls for familial confounding. Sex-stratified analyses indicated high internalising symptoms were associated with increased between-pair odds of obesity for females (AOR 12.9, 95% CI 2.2, 76.8), but this attenuated to the null using within-pair analysis. We found no evidence of between or within-pair associations for males and weak evidence that sex modified the association between internalising symptoms and obesity (likelihood ratio test p = 0.051). CONCLUSIONS: Some familial factors shared by twins confound the association between internalising symptoms and obesity in adolescent and young adult females. Internalising symptoms and obesity were not associated for adolescent and young adult males. Therefore, prevention and treatment efforts should especially address familial shared determinants of obesity, particularly targeted at female adolescents and young adults with internalising symptoms and those with a family history of these disorders.
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ItemPsychometric Performance Comparison of the Adapted versus Original Versions of the EQ-5D-Y-3L and -Y-5L in Proxy Respondents for 2-to 4-Year-Olds(ADIS INT LTD, 2024-01-18)INTRODUCTION: Few preference-weighted instruments are available to measure health-related quality of life in young children (2-4 years of age). The EQ-5D-Y-3L and EQ-5D-Y-5L were recently modified for this purpose. OBJECTIVE: The aim of this study was to test the psychometric properties of these adapted versions for use with parent proxies of children aged 2-4 years and to compare their performance with the original versions. It was hypothesised that the adapted instrument wording would result in improved psychometric performance. METHODS: Survey data of children aged 2-4 years were obtained from the Australian Paediatric Multi-Instrument Comparison study. Distributional and psychometric properties tested included feasibility, convergence, distribution of level scores, ceiling effects, known-group validity (Cohen's D effect sizes for prespecified groups defined by the presence/absence of special healthcare needs [SHCNs]), test-retest reliability (intraclass correlation coefficients [ICCs]), and responsiveness (standardised response mean [SRM] effect sizes for changes in health). Level sum scores were used to provide summary outcomes. Supplementary analysis using utility scores (from the Swedish EQ-5D-Y-3L value set) were conducted for the adapted and original EQ-5D-Y-3L, and no value sets were available for the EQ-5D-Y-5L. RESULTS: A total of 842 parents of children aged 2-4 years completed the survey. All instruments were easy to complete. There was strong convergence between the adapted and original EQ-5D-Y-3L and EQ-5D-Y-5L. The adapted EQ-5D-Y-3L and adapted EQ-5D-Y-5L showed more responses in the severe levels of the five EQ-5D-Y dimensions, particularly in the usual activity and mobility dimensions (EQ-5D-Y-5L: mobility level 1: adapted n = 478 [83%], original n = 253 [94%]; mobility level 4/5: adapted n = 17 [2.9%], original n = 4 [1.5%)]). The difference in the distribution of responses was more evident in children with SHCNs. Assessment of known-group validity showed a greater effect size for the adapted EQ-5D-Y-3L and adapted EQ-5D-Y-5L compared with the original instruments (EQ-5D-Y-5L: adapted Cohen's D = 1.01, original Cohen's D = 0.83) between children with and without SHCNs. The adapted EQ-5D-Y-3L and adapted EQ-5D-Y-5L showed improved reliability at 4-week follow-up, with improved ICCs (EQ-5D-Y-5L: adapted ICC = 0.83, original ICC = 0.44). The responsiveness of all instruments moved in the hypothesised direction for better or worse health at follow-up. Probability of superiority analysis showed little/no differences between the adapted and original EQ-5D-Y-3L and EQ-5D-Y-5L. Supplementary psychometric analysis of the adapted and original EQ-5D-Y-3L using utilities showed comparable findings with analyses using level sum scores. CONCLUSIONS: The findings suggest improved psychometric performance of the adapted version of the EQ-5D-Y-3L and EQ-5D-Y-5L in children aged 2-4 years compared with the original versions.
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ItemComparison of new computational methods for spatial modelling of malaria.(Springer Science and Business Media LLC, 2023-11-21)BACKGROUND: Geostatistical analysis of health data is increasingly used to model spatial variation in malaria prevalence, burden, and other metrics. Traditional inference methods for geostatistical modelling are notoriously computationally intensive, motivating the development of newer, approximate methods for geostatistical analysis or, more broadly, computational modelling of spatial processes. The appeal of faster methods is particularly great as the size of the region and number of spatial locations being modelled increases. METHODS: This work presents an applied comparison of four proposed 'fast' computational methods for spatial modelling and the software provided to implement them-Integrated Nested Laplace Approximation (INLA), tree boosting with Gaussian processes and mixed effect models (GPBoost), Fixed Rank Kriging (FRK) and Spatial Random Forests (SpRF). The four methods are illustrated by estimating malaria prevalence on two different spatial scales-country and continent. The performance of the four methods is compared on these data in terms of accuracy, computation time, and ease of implementation. RESULTS: Two of these methods-SpRF and GPBoost-do not scale well as the data size increases, and so are likely to be infeasible for larger-scale analysis problems. The two remaining methods-INLA and FRK-do scale well computationally, however the resulting model fits are very sensitive to the user's modelling assumptions and parameter choices. The binomial observation distribution commonly used for disease prevalence mapping with INLA fails to account for small-scale overdispersion present in the malaria prevalence data, which can lead to poor predictions. Selection of an appropriate alternative such as the Beta-binomial distribution is required to produce a reliable model fit. The small-scale random effect term in FRK overcomes this pitfall, but FRK model estimates are very reliant on providing a sufficient number and appropriate configuration of basis functions. Unfortunately the computation time for FRK increases rapidly with increasing basis resolution. CONCLUSIONS: INLA and FRK both enable scalable geostatistical modelling of malaria prevalence data. However care must be taken when using both methods to assess the fit of the model to data and plausibility of predictions, in order to select appropriate model assumptions and parameters.