Melbourne School of Population and Global Health - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 3890
-
ItemThe global burden of adolescent and young adult cancer in 2019: a systematic analysis for the Global Burden of Disease Study 2019(ELSEVIER SCIENCE INC, 2022-01)BACKGROUND: In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. METHODS: Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. FINDINGS: There were 1·19 million (95% UI 1·11-1·28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59·6 [54·5-65·7] per 100 000 person-years) and high-middle SDI countries (53·2 [48·8-57·9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14·2 [12·9-15·6] per 100 000 person-years) and middle SDI (13·6 [12·6-14·8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23·5 million (21·9-25·2) DALYs to the global burden of disease, of which 2·7% (1·9-3·6) came from YLDs and 97·3% (96·4-98·1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. INTERPRETATION: Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. FUNDING: Bill & Melinda Gates Foundation, American Lebanese Syrian Associated Charities, St Baldrick's Foundation, and the National Cancer Institute.
-
ItemThe global burden of cancer attributable to risk factors, 2010-19: a systematic analysis for the Global Burden of Disease Study 2019(ELSEVIER SCIENCE INC, 2022-08-20)BACKGROUND: Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. METHODS: The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. FINDINGS: Globally, in 2019, the risk factors included in this analysis accounted for 4·45 million (95% uncertainty interval 4·01-4·94) deaths and 105 million (95·0-116) DALYs for both sexes combined, representing 44·4% (41·3-48·4) of all cancer deaths and 42·0% (39·1-45·6) of all DALYs. There were 2·88 million (2·60-3·18) risk-attributable cancer deaths in males (50·6% [47·8-54·1] of all male cancer deaths) and 1·58 million (1·36-1·84) risk-attributable cancer deaths in females (36·3% [32·5-41·3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20·4% (12·6-28·4) and DALYs by 16·8% (8·8-25·0), with the greatest percentage increase in metabolic risks (34·7% [27·9-42·8] and 33·3% [25·8-42·0]). INTERPRETATION: The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. FUNDING: Bill & Melinda Gates Foundation.
-
ItemImpact of informal caregiving on depressive symptoms among a national cohort of men(BMJ PUBLISHING GROUP, 2024-04-07)BACKGROUND: There is evidence that unpaid caregiving can have negative effects on the mental health of female caregivers; however, evidence of impacts on male caregivers is limited. This study addressed this gap by examining associations between becoming a caregiver and depressive symptoms among men. METHODS: We used data from waves 1-2 (2013, 2016) of the Longitudinal Study of Australian Male Health (Ten to Men). Effects of incident caregiving on depressive symptoms were estimated using augmented inverse probability treatment weighting, with adjustment for potential confounders. Incident caregiving was assessed as a binary variable (became a caregiver vs not), and depressive symptoms were measured using the Patient Health Questionnaire (moderate to severe depressive symptoms; yes, no). Main analysis was prospective, drawing on wave 1 (caregiving) and wave 2 (depressive symptoms), and sensitivity analyses modelled cross-sectional associations. RESULTS: In the main analysis, incident caregiving in wave 1 was associated with depressive symptoms in the subsequent wave, with an average treatment effect of 0.11 (95% CI 0.06, 0.17) and equating to a risk ratio of 2.03 (95% CI 1.55, 2.51). Associations were robust to several sensitivity analyses, with cross-sectional associations supporting the main prospective analyses. CONCLUSION: These results provide evidence of the association between caregiving and depressive symptoms among male caregivers. This has important implications for policy and support programmes. As we seek to shift caregiving responsibilities toward a more gender-equal distribution of care, policy must recognise that, like female caregivers, male caregivers also experience mental health impacts related to their caregiving role.
-
ItemNo Preview AvailableSpatio-temporal spread of artemisinin resistance in Southeast Asia(PUBLIC LIBRARY SCIENCE, 2024-04)Current malaria elimination targets must withstand a colossal challenge-resistance to the current gold standard antimalarial drug, namely artemisinin derivatives. If artemisinin resistance significantly expands to Africa or India, cases and malaria-related deaths are set to increase substantially. Spatial information on the changing levels of artemisinin resistance in Southeast Asia is therefore critical for health organisations to prioritise malaria control measures, but available data on artemisinin resistance are sparse. We use a comprehensive database from the WorldWide Antimalarial Resistance Network on the prevalence of non-synonymous mutations in the Kelch 13 (K13) gene, which are known to be associated with artemisinin resistance, and a Bayesian geostatistical model to produce spatio-temporal predictions of artemisinin resistance. Our maps of estimated prevalence show an expansion of the K13 mutation across the Greater Mekong Subregion from 2000 to 2022. Moreover, the period between 2010 and 2015 demonstrated the most spatial change across the region. Our model and maps provide important insights into the spatial and temporal trends of artemisinin resistance in a way that is not possible using data alone, thereby enabling improved spatial decision support systems on an unprecedented fine-scale spatial resolution. By predicting for the first time spatio-temporal patterns and extents of artemisinin resistance at the subcontinent level, this study provides critical information for supporting malaria elimination goals in Southeast Asia.
-
ItemNo Preview AvailableTrajectories of job insecurity and the probability of poorer mental health among prime working-age Australian women and men.(Elsevier BV, 2024-05)Precarious and insecure employment arrangements are important social determinants of health. Prior evidence has consistently found perceived job insecurity to be associated with poorer mental health. Nonetheless, several key under-researched areas remain in the existing evidence base. This study addresses some of these gaps by examining trajectories of job (in)security and assessing the effect of various persistent job security trajectories on subsequent mental health of both men and women. Utilising 15 waves of data from the Household, Income and Labour Dynamics in Australia (HILDA) Survey, we employed group-based trajectory modelling (GBTM) to identify trajectories of job (in)security through men and women's prime working years (from baseline age of 28-38yrs to 41-51yrs) across 14 years (waves 5-18), before subsequently examining the associations between these estimated trajectories and mental health at wave 19 (aged 42-52yrs). We identified four distinct trajectories of job (in)security for both men and women: persistently secure, becoming more secure, becoming less secure, and persistently insecure. Examining the association between these trajectories and mental health, we found that chronic exposure to any amount of persistent job insecurity (improving, worsening or persistently insecure) is detrimental to the mental health of both men and women. Furthermore, a somewhat incremental or dose dependant effect was found, with persistent job insecurity associated with the largest declines in mental health scores. Given mental health disorders are a substantial cause of disability globally, our study provides evidence that developing policy and practice interventions to reduce job insecurity (as an increasingly recognised and highly modifiable social determinant of mental health) has considerable potential to enact positive population health improvements.
-
ItemNo Preview AvailablePoint-of-care testing and treatment of sexually transmitted and genital infections to improve birth outcomes in high-burden, low-resource settings (WANTAIM): a pragmatic cluster randomised crossover trial in Papua New Guinea.(Elsevier BV, 2024-04)BACKGROUND: Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and bacterial vaginosis have been associated with adverse maternal and perinatal outcomes, but there is conflicting evidence on the benefits of antenatal screening and treatment for these conditions. We aimed to determine the effect of antenatal point-of-care testing and immediate treatment of C trachomatis, N gonorrhoeae, T vaginalis, and bacterial vaginosis on preterm birth, low birthweight, and other adverse maternal and perinatal outcomes compared with current standard of care, which included symptom-based treatment without laboratory confirmation. METHODS: In this pragmatic cluster randomised crossover trial, we enrolled women (aged ≥16 years) attending an antenatal clinic at 26 weeks' gestation or earlier (confirmed by obstetric ultrasound), living within approximately 1 h drive of a study clinic, and able to provide reliable contact details at ten primary health facilities and their catchment communities (clusters) in Papua New Guinea. Clusters were randomly allocated 1:1 to receive either the intervention or control (standard care) in the first phase of the trial. Following an interval (washout period) of 2-3 months at the end of the first phase, each cluster crossed over to the other group. Randomisation was stratified by province. Individual participants were informed about trial group allocation only after completing informed consent procedures. The primary outcome was a composite of preterm birth (livebirth before 37 weeks' gestation), low birthweight (<2500 g), or both, analysed according to the intention-to-treat population. This study is registered with ISRCTN Registry, ISRCTN37134032, and is completed. FINDINGS: Between July 26, 2017, and Aug 30, 2021, 4526 women were enrolled (2210 [63·3%] of 3492 women in the intervention group and 2316 [62·8%] of 3687 in the control group). Primary outcome data were available for 4297 (94·9%) newborn babies of 4526 women. The proportion of preterm birth, low birthweight, or both, in the intervention group, expressed as the mean of crude proportions across clusters, was 18·8% (SD 4·7%) compared with 17·8% in the control group (risk ratio [RR] 1·06, 95% CI 0·78-1·42; p=0·67). There were 1052 serious adverse events reported (566 in the intervention group and 486 in the control group) among 929 trial participants, and no differences by trial group. INTERPRETATION: Point-of-care testing and treatment of C trachomatis, N gonorrhoeae, T vaginalis, and bacterial vaginosis did not reduce preterm birth or low birthweight compared with standard care. Within the subgroup of women with N gonorrhoeae, there was a substantial reduction in the primary outcome. FUNDING: UK Department of Health and Social Care; UK Foreign, Commonwealth and Development Office; UK Medical Research Council; the Wellcome Trust; the Australian National Health and Medical Research Council; and Swiss National Science Foundation.
-
ItemNo Preview AvailableEthical frameworks should be applied to computational modelling of infectious disease interventions(PUBLIC LIBRARY SCIENCE, 2024-03)This perspective is part of an international effort to improve epidemiological models with the goal of reducing the unintended consequences of infectious disease interventions. The scenarios in which models are applied often involve difficult trade-offs that are well recognised in public health ethics. Unless these trade-offs are explicitly accounted for, models risk overlooking contested ethical choices and values, leading to an increased risk of unintended consequences. We argue that such risks could be reduced if modellers were more aware of ethical frameworks and had the capacity to explicitly account for the relevant values in their models. We propose that public health ethics can provide a conceptual foundation for developing this capacity. After reviewing relevant concepts in public health and clinical ethics, we discuss examples from the COVID-19 pandemic to illustrate the current separation between public health ethics and infectious disease modelling. We conclude by describing practical steps to build the capacity for ethically aware modelling. Developing this capacity constitutes a critical step towards ethical practice in computational modelling of public health interventions, which will require collaboration with experts on public health ethics, decision support, behavioural interventions, and social determinants of health, as well as direct consultation with communities and policy makers.
-
ItemNo Preview AvailableEstimating measures to reduce the transmission of SARS-CoV-2 in Australia to guide a 'National Plan' to reopening.(Elsevier BV, 2024-03-19)The availability of COVID-19 vaccines promised a reduction in the severity of disease and relief from the strict public health and social measures (PHSMs) imposed in many countries to limit spread and burden of COVID-19. We were asked to define vaccine coverage thresholds for Australia's transition to easing restrictions and reopening international borders. Using evidence of vaccine effectiveness against the then-circulating Delta variant, we used a mathematical model to determine coverage targets. The absence of any COVID-19 infections in many sub-national jurisdictions in Australia posed particular methodological challenges. We used a novel metric called Transmission Potential (TP) as a proxy measure of the population-level effective reproduction number. We estimated TP of the Delta variant under a range of PHSMs, test-trace-isolate-quarantine (TTIQ) efficiencies, vaccination coverage thresholds, and age-based vaccine allocation strategies. We found that high coverage across all ages (≥70%) combined with ongoing TTIQ and minimal PHSMs was sufficient to avoid lockdowns. At lesser coverage (≤60%) rapid case escalation risked overwhelming of the health sector or the need to reimpose stricter restrictions. Maintaining low case numbers was most beneficial for health and the economy, and at higher coverage levels (≥80%) further easing of restrictions was deemed possible. These results directly informed easing of COVID-19 restrictions in Australia.
-
ItemNo Preview AvailableEstimating the impact of test-trace-isolate-quarantine systems on SARS-CoV-2 transmission in Australia.(Elsevier BV, 2024-03-22)BACKGROUND: Australian states and territories used test-trace-isolate-quarantine (TTIQ) systems extensively in their response to the COVID-19 pandemic in 2020-2021. We report on an analysis of Australian case data to estimate the impact of test-trace-isolate-quarantine systems on SARS-CoV-2 transmission. METHODS: Our analysis uses a novel mathematical modelling framework and detailed surveillance data on COVID-19 cases including dates of infection and dates of isolation. First, we directly translate an empirical distribution of times from infection to isolation into reductions in potential for onward transmission during periods of relatively low caseloads (tens to hundreds of reported cases per day). We then apply a simulation approach, validated against case data, to assess the impact of case-initiated contact tracing on transmission during a period of relatively higher caseloads and system stress (up to thousands of cases per day). RESULTS: We estimate that under relatively low caseloads in the state of New South Wales (tens of cases per day), TTIQ contributed to a 54% reduction in transmission. Under higher caseloads in the state of Victoria (hundreds of cases per day), TTIQ contributed to a 42% reduction in transmission. Our results also suggest that case-initiated contact tracing can support timely quarantine in times of system stress (thousands of cases per day). CONCLUSION: Contact tracing systems for COVID-19 in Australia were highly effective and adaptable in supporting the national suppression strategy from 2020-21, prior to the emergence of the Omicron variant in November 2021. TTIQ systems were critical to the maintenance of the strong suppression strategy and were more effective when caseloads were (relatively) low.
-
ItemNo Preview AvailableMathematical models of Plasmodium vivax transmission: A scoping review(PUBLIC LIBRARY SCIENCE, 2024-03)Plasmodium vivax is one of the most geographically widespread malaria parasites in the world, primarily found across South-East Asia, Latin America, and parts of Africa. One of the significant characteristics of the P. vivax parasite is its ability to remain dormant in the human liver as hypnozoites and subsequently reactivate after the initial infection (i.e. relapse infections). Mathematical modelling approaches have been widely applied to understand P. vivax dynamics and predict the impact of intervention outcomes. Models that capture P. vivax dynamics differ from those that capture P. falciparum dynamics, as they must account for relapses caused by the activation of hypnozoites. In this article, we provide a scoping review of mathematical models that capture P. vivax transmission dynamics published between January 1988 and May 2023. The primary objective of this work is to provide a comprehensive summary of the mathematical models and techniques used to model P. vivax dynamics. In doing so, we aim to assist researchers working on mathematical epidemiology, disease transmission, and other aspects of P. vivax malaria by highlighting best practices in currently published models and highlighting where further model development is required. We categorise P. vivax models according to whether a deterministic or agent-based approach was used. We provide an overview of the different strategies used to incorporate the parasite's biology, use of multiple scales (within-host and population-level), superinfection, immunity, and treatment interventions. In most of the published literature, the rationale for different modelling approaches was driven by the research question at hand. Some models focus on the parasites' complicated biology, while others incorporate simplified assumptions to avoid model complexity. Overall, the existing literature on mathematical models for P. vivax encompasses various aspects of the parasite's dynamics. We recommend that future research should focus on refining how key aspects of P. vivax dynamics are modelled, including spatial heterogeneity in exposure risk and heterogeneity in susceptibility to infection, the accumulation of hypnozoite variation, the interaction between P. falciparum and P. vivax, acquisition of immunity, and recovery under superinfection.