Melbourne School of Population and Global Health - Research Publications
Now showing items 1-12 of 2586
Epidemiological consequences of enduring strain-specific immunity requiring repeated episodes of infection
(PUBLIC LIBRARY SCIENCE, 2020-06-01)
Group A Streptococcus (GAS) skin infections are caused by a diverse array of strain types and are highly prevalent in disadvantaged populations. The role of strain-specific immunity in preventing GAS infections is poorly understood, representing a critical knowledge gap in vaccine development. A recent GAS murine challenge study showed evidence that sterilising strain-specific and enduring immunity required two skin infections by the same GAS strain within three weeks. This mechanism of developing enduring immunity may be a significant impediment to the accumulation of immunity in populations. We used an agent-based mathematical model of GAS transmission to investigate the epidemiological consequences of enduring strain-specific immunity developing only after two infections with the same strain within a specified interval. Accounting for uncertainty when correlating murine timeframes to humans, we varied this maximum inter-infection interval from 3 to 420 weeks to assess its impact on prevalence and strain diversity, and considered additional scenarios where no maximum inter-infection interval was specified. Model outputs were compared with longitudinal GAS surveillance observations from northern Australia, a region with endemic infection. We also assessed the likely impact of a targeted strain-specific multivalent vaccine in this context. Our model produced patterns of transmission consistent with observations when the maximum inter-infection interval for developing enduring immunity was 19 weeks. Our vaccine analysis suggests that the leading multivalent GAS vaccine may have limited impact on the prevalence of GAS in populations in northern Australia if strain-specific immunity requires repeated episodes of infection. Our results suggest that observed GAS epidemiology from disease endemic settings is consistent with enduring strain-specific immunity being dependent on repeated infections with the same strain, and provide additional motivation for relevant human studies to confirm the human immune response to GAS skin infection.
Exposure to discrimination and subsequent changes in self-rated health: prospective evidence from the UK's Life Opportunities Survey.
(Elsevier BV, 2020-08)
OBJECTIVES: We sought to estimate risk of poor self-rated health (SRH) following exposure to disability-related and other forms of overt discrimination in a cohort of working age adults. STUDY DESIGN: The study design is a population-based cohort survey. METHODS: Secondary analysis of data collected in Waves 1 and 2 of the UK's Life Opportunities Survey which at Wave 2 involved the participation of 12,789 working age adults. Adjusted prevalence rate ratios were used to estimate the impact of exposure to disability and non-disability discrimination on two measures of SRH at Wave 2, controlling for SRH status at Wave 1. RESULTS: Exposure to disability discrimination in the previous year was reported by 3.9% of working age British adults. Other forms of discrimination were reported less frequently (age: 3.7%, ethnicity: 2.5%, gender: 1.6%, religion: 0.8%, sexual orientation: 0.4%). In all analyses, there were stronger associations between exposure to disability discrimination and poor SRH at Wave 2 when compared with exposure to other forms of discrimination. CONCLUSIONS: Disability discrimination represents a violation of human rights. It is also likely to be a major contributor to the health inequities experienced by working age adults with disability.
Reordering gender systems: can COVID-19 lead to improved gender equality and health?
COVID-19 has delivered a shock to existing gender systems that could recalibrate gender roles, with beneficial effects on population health. The economic arrangements, policy frameworks, and market forces that determine the distribution of paid and unpaid labour across society are powerful structural determinants of health.1 The way that paid and unpaid labour is inequitably divided between men and women is central to the perpetuation of gender inequalities across the globe, and the ways that such divisions can be shifted or disrupted offer critical opportunities to modify the gender-differentiated effects of COVID-19 on health.
Experiences of racial discrimination and cardiometabolic risk among Australian children
(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2020-07-01)
Cardiometabolic disease is a leading cause of adult morbidity and mortality globally. There is considerable evidence that childhood adversity is associated with markers of cardiometabolic disease risk in childhood, including obesity, blood pressure trajectories, and chronic inflammation. Experiences of racial discrimination may be an important, yet under explored, form of childhood adversity influencing childhood cardiometabolic risk. This study aimed to examine associations between self-reported racial discrimination and cardiometabolic risk markers among children. A total of 124 children (73 female) aged 11.4 years (SD 0.71) participated in the study. Most children (n = 79) identified as being from an Indigenous or an ethnic minority background. Markers of cardiometabolic risk were BMI, waist circumference, weight height ratio, systolic and diastolic blood pressure, and five inflammatory markers (C-reactive protein (CRP), Interleukin (IL)-1β, IL-6, IL-8, and TNF-α). Results showed that two or more reported experiences of racial discrimination were associated with increased BMI z-score (Beta 0.58, 95% CI 0.18, 0.99), waist circumference (Beta 4.91 cm, 95% CI 0.71, 9.1), systolic blood pressure (Beta 2.07 mmHg, 95% CI 0.43, 3.71) and IL-6 (Beta 0.13, 95% CI 0.00, 0.27) and marginally associated with TNF-α (Beta 0.22, 95% CI -0.09, 0.54) after adjusting for socio-demographic covariates. Findings from this study suggest the need to address racism and racial discrimination as important social determinants of cardiometabolic risk and of the inequitable burden of cardiometabolic disease experienced by those from Indigenous and minoritized ethnic backgrounds.
The impact of the disability support pension on mental health: evidence from 14 years of an Australian cohort
OBJECTIVE: To assess the effect of the Australian Disability Support Pension (DSP) on the symptomology of depression and anxiety over and above the effects of reporting a disability itself. METHODS: We used the Household Income Labour Dynamics in Australia (HILDA) survey from 2004 to 2017. We used fixed effects regression to understand mental health differences (using the Mental Health Inventory-5 [MHI-5]) when a person reported: i) a disability; or ii) a disability and receiving the DSP) compared to when they reported no disability. The models controlled for time-varying changes in the severity of the disability and other time-related confounders. RESULTS: There was a 2.97-point decline (95%CI -3.26 to -2.68) in the MHI-5 when a person reported a disability compared to waves in which they reported no disability and 4.48-point decline (95%CI -5.75 to -3.22) when a person reported both a disability and being on the DSP compared to waves in which they reported neither. CONCLUSIONS: Results suggest that accessing and being in receipt of the DSP can impact the mental health of people with disabilities. Implications for public health: Government income support policies should address the unintended adverse consequences in already vulnerable populations.
Breadwinners and Losers: Does the Mental Health of Mothers, Fathers and Children Vary by Household Employment Arrangements? Evidence From Seven Waves of Data From the Longitudinal Study of Australian Children.
(Oxford University Press (OUP), 2020-07-14)
In Australia, as in many industrialized countries, the past 50years have been marked by increasing female labor-force participation. It is popularly speculated that this may impose a mental health burden on women and their children. This analysis aimed to examine the associations between household labor-force participation (household employment-configuration) and the mental health of parents and children. Seven waves of data from the Longitudinal Study of Australian Children were used, (2004-2016, children aged 4/5-16/17 years). Mental health outcome measures were Strengths and Difficulties Questionnaire (children/adolescents), and Kessler-6 (parents). A five-category measure of household employment-configuration was derived from parental reports: both parents full-time, male-breadwinner, female-breadwinner, shared-part-time employment (both part-time) and father full-time/mother part-time (1.5-earner). Fixed-effects regression models were used to compare within-person effects, controlling for time-varying confounders. For men, the male-breadwinner configuration was associated with poorer mental health compared to when in the 1.5-earner configuration (ß = 0.21, 95%CI 0.05-0.36). No evidence of association was observed for either women or children. This counters prevailing social attitudes, suggesting that neither children nor women are adversely affected by household employment-configuration, nor are they disadvantaged by the extent of this labor-force participation. Men's mental health appears to be poorer when they are the sole household breadwinner.
Racial discrimination and socioemotional and sleep problems in a cross-sectional survey of Australian school students.
OBJECTIVE: To determine the prevalence of direct and vicarious racial discrimination experiences from peer, school and societal sources, and examine associations between these experiences and socioemotional and sleep outcomes. METHODS: Data were analysed from a population representative cross-sectional study of n=4664 school students in years 5-9 (10-15 years of age) in Australia. Students reported direct experiences of racial discrimination from peers, school and societal sources; vicarious discrimination was measured according to the frequency of witnessing other students experiences of racial discrimination. Students self-reported on the Strengths and Difficulties Questionnaire, with the total difficulties, conduct, emotional and prosocial behaviour subscales examined. Sleep problems included duration, latency, and disruption. RESULTS: 41.56% (95% CI 36.18 to 47.15) of students reported experiences of direct racial discrimination; Indigenous and ethnic minority students reported the highest levels. 70.15% (95% CI 63.83 to 75.78) of students reported vicarious racial discrimination. Direct and vicarious experiences of racial discrimination were associated with socioemotional adjustment (eg, for total difficulties, total direct racism: beta=3.77, 95% CI 3.11 to 4.44; vicarious racism: beta=2.51, 95% CI 2.00 to 3.03). Strong evidence was also found for an effect of direct and vicarious discrimination on sleep (eg, for sleep duration, total direct: beta=-21.04, 95% CI -37.67 to -4.40; vicarious: beta=-9.82, 95% CI -13.78 to -5.86). CONCLUSIONS: Experiences of direct and vicarious racial discrimination are common for students from Indigenous and ethnic minority backgrounds, and are associated with socioemotional and sleep problems in adolescence. Racism and racial discrimination are critically important to tackle as social determinants of health for children and adolescents.
Social Correlates of Recent Suicidal Ideation Among Men Who Have Sex with Men in Greater Tokyo
(Springer Verlag, 2020-01-01)
Introduction: Suicide is a major public health problem in Japan, where mortality rates are among the highest in the world. Globally, men who have sex with men (MSM) report elevated rates of suicidal ideation and attempts compared to their heterosexual peers. However, there is a paucity of research on suicidal ideation among MSM in Japan, where MSM continue to experience significant stigma and discrimination, and where resources are limited for MSM-specific mental health support. Methods: This study examined the prevalence and correlates of recent suicidal ideation among MSM in Greater Tokyo. We recruited 1,657 MSM for an anonymous, online, cross-sectional survey posted on social mobile applications popular with MSM in Japan (e.g., Grindr, 9Monsters) from November 2015 through January 2016. Results: Recent suicidal ideation, measured as suicidal thoughts in the preceding two weeks, was reported by almost one-third (31%) of participants. Participants who reported unemployment or part-time employment (compared to full-time employment) and knowing a heterosexual person who restricted their freedom or excluded them from a group had higher odds of suicidal ideation. Being aged 46 years or older, reporting good health, and having a medium or high level of access to social capital networks with other MSM were associated with reduced odds of suicidal ideation. Conclusions and Policy Implications: Our findings indicate that suicide prevention interventions with MSM in Greater Tokyo and similar urban settings in Japan should work to enhance MSM social networks as a protective factor; attend to employment concerns, particularly in younger MSM; and augment current efforts to address stigma and discrimination in the community.
Temporal variations in the distribution of self-harm episodes and methods across the Australian asylum seeker population: An observational study
(PUBLIC LIBRARY SCIENCE, 2020-08-01)
BACKGROUND: Temporal patterns in the frequency and characteristics of self-harm episodes across the Australian asylum seeker population may have implications for self-harm prevention and public health policy. The aim of this study was to examine how the distribution of self-harm episodes and method(s) of self-harm used across the Australian asylum seeker population vary according to the 24-hour cycle, day, and month, and to establish a basis for further research. METHODS AND FINDINGS: We conducted an observational study of all 949 self-harm incidents reported across the Australian asylum seeker population (representing a monthly average of 28,992 adults) between 1 August 2014 and 31 July 2015, obtained by Freedom of Information (FOI) from the Department of Immigration. Time of self-harm, day, and month of occurrence were investigated across all five Australian asylum seeker populations (i.e., community-based arrangements, community detention, onshore immigration detention, offshore immigration detention [Nauru], and offshore immigration detention [Manus Island]). Significant variations in distributions over the 24-hour cycle were observed by processing arrangements. Compared with the average distribution across all other processing arrangements, self-harm more commonly occurred among community-based asylum seekers (36.3%) between 12:00 AM and 3:59 AM (p < 0.001), in asylum seekers on Manus Island (36.4%) between 4:00 PM and 7:59 PM (p = 0.02), and among asylum seekers in onshore detention (20.4%) between 8:00 PM and 11:59 PM (p < 0.001). Compared with the average distribution across all other methods, self-poisoning (by medication) (25%) was significantly more likely to occur between 12:00 AM and 3:59 AM (p = 0.009), and self-battery (42%) between 8:00 AM and 11:59 AM (p < 0.001). The highest and lowest monthly self-harm episode rates for the whole asylum seeker population were in August (2014) (5 episodes per 1,000 asylum seekers; 95% confidence interval [CI] 1-11) and in both January and February (2015) (2.1 episodes per 1,000 asylum seekers; 95% CI 0.6-7.2), respectively; however, the overlapping CIs indicate no statistically significant differences across the months. When examining monthly trends by processing arrangements, we observed that self-harm was significantly more likely to occur in August (2014) than other months of the year among asylum seekers in onshore detention (19%) (p < 0.001), in January (2015) on Manus Island (18%) (p = 0.002), and in October (2014) on Nauru (15%) (p < 0.001). The main study limitations were that we could not investigate certain characteristics associated with self-harm (e.g., gender, country of origin), as the Department of Immigration did not routinely collect such data. There was also the potential risk of making a type 1 error, given the exploratory nature of the comparisons we undertook; we minimised this by lowering our significance threshold from 0.05 to 0.01. CONCLUSIONS: Self-harm in the Australian asylum seeker population was found to vary according to time of day and month of the year, by processing arrangements. A series of procedure-related and detention-related factors were observed to be associated with the temporal variations in self-harm. These findings should form the basis for further investigation into temporal variations in self-harm among asylum seekers, which may in turn lead to effective self-harm prevention strategies.
Equitable Expanded Carrier Screening Needs Indigenous Clinical and Population Genomic Data
(CELL PRESS, 2020-08-06)
Expanded carrier screening (ECS) for recessive monogenic diseases requires prior knowledge of genomic variation, including DNA variants that cause disease. The composition of pathogenic variants differs greatly among human populations, but historically, research about monogenic diseases has focused mainly on people with European ancestry. By comparison, less is known about pathogenic DNA variants in people from other parts of the world. Consequently, inclusion of currently underrepresented Indigenous and other minority population groups in genomic research is essential to enable equitable outcomes in ECS and other areas of genomic medicine. Here, we discuss this issue in relation to the implementation of ECS in Australia, which is currently being evaluated as part of the national Government's Genomics Health Futures Mission. We argue that significant effort is required to build an evidence base and genomic reference data so that ECS can bring significant clinical benefit for many Aboriginal and/or Torres Strait Islander Australians. These efforts are essential steps to achieving the Australian Government's objectives and its commitment "to leveraging the benefits of genomics in the health system for all Australians." They require culturally safe, community-led research and community involvement embedded within national health and medical genomics programs to ensure that new knowledge is integrated into medicine and health services in ways that address the specific and articulated cultural and health needs of Indigenous people. Until this occurs, people who do not have European ancestry are at risk of being, in relative terms, further disadvantaged.