Cohort Profile: The Western Australian Family Connections Genealogical Project

Aggregation of melanoma tumour site within Western Australian families

BACKGROUND

Evidence is emerging that melanoma has distinct aetiologic pathways and subtypes, characterized by factors like anatomic site of the tumour. To explore genetic influences on anatomic subtypes, we examined the extent to which melanomas in first-degree relatives shared the same body site of occurrence.

METHODS

Population-level linked data was used to identify the study population of over 1.5 million individuals born in Western Australia between 1945 and 2014, and their first-degree relatives. There were 1009 pairs of invasive tumours from 677 family pairs, each categorised by anatomic site. Greater than expected representation of site-concordant pairs would suggest the presence of genetic factors that predispose individuals to site-specific melanoma.

RESULTS

Comparing observed versus expected totals, we observed a modest increase in site concordance for invasive head/neck and truncal tumours (P=0.02). A corresponding analysis including in situ tumours showed a similar concordance (P=0.05). No further evidence of concordance was observed when stratified by sex.

CONCLUSION

In conclusion, modest evidence of aggregation was observed but with inconsistent patterns between sites. Results suggest that further investigation into the familial aggregation of melanoma by tumour site is warranted, with the inclusion of genetic data in order to disentangle the relative contributions of genetic and environmental factors.

Hospital and emergency department discharge against medical advice in Western Australian Aboriginal children aged 0-4 years from 2002 to 2018: A cohort study

BACKGROUND

Discharge against medical advice (DAMA) is a priority issue for the health system. Little is known about the factors associated with DAMA for Aboriginal and/or Torres Strait Islander (Aboriginal) children in Australia.

OBJECTIVES

Investigate the associations between DAMA for hospital admissions and emergency department (ED) presentations and: (i) child, family and episode of service characteristics and (ii) 30-day readmission/ re-presentation.

METHODS

We conducted a cohort study of Aboriginal children born in Western Australia (2002-2013) who had ≥1 hospital admissions (n = 16,931) or ED presentations (n = 26,546) within the first 5 years of life. The outcome of interest was hospital and ED DAMA and adjusted odds ratio were derived using multilevel mixed-effects logistic regression.

RESULTS

In the Hospital Cohort, there were 43,149 hospitalisations for 16,931 children, with 684 hospitalisations (1.6%) recorded as DAMA. In the ED Cohort, there were 232,082 ED presentations in 26,546 children, with 10,918 ED presentations (4.7%) recorded as DAMA. DAMA occurring in hospitals between 2014 and 2018, the adjusted odds decreased by 75% compared to the period between 2002 and 2005. The adjusted odds of ED DAMA increased by 46% over the same period. Hospital admissions in regional and remote hospitals were almost seven times the adjusted odds of DAMA compared with hospital admissions in Perth metropolitan hospitals. The adjusted odds of ED DAMA decreased by 12% for ED presentations in regional and remote hospitals compared to those in Perth metropolitan hospitals. There was no evidence of hospital DAMA being associated with hospital readmission within 30 days and limited evidence of ED DAMA being associated with re-presenting to an ED within 30 days.

CONCLUSIONS

The study identified several important determinants of DAMA, including admission status, triage status, location and calendar year. These findings could inform targeted measures to decrease DAMA, particularly in regional and remote communities.

Reproductive and sexual health of Australian adolescents exposed to family and domestic violence

BACKGROUND

There is a dearth of research investigating sexually transmitted infections (STIs) in children exposed to family and domestic violence (FDV). Further, there is no research on terminations of pregnancy in children exposed to FDV.

METHODS

This retrospective cohort study used linked administrative data from Western Australia to investigate whether exposure to FDV is associated with a risk of hospitalisations for STIs and terminations of pregnancy in adolescents. This study involved children born from 1987 to 2010 whose mother was a victim of FDV. Identification of family and domestic violence was from two sources: police and hospital records. This approach provided an exposed cohort of 16 356 and a non-exposed cohort of 41 996. Dependant variables were hospitalisations for pregnancy terminations and STIs in children aged from 13 up to 18 years of age. The primary explanatory variable was exposure to FDV. Multivariable Cox regression was used to investigate the association of FDV exposure and the outcomes.

RESULTS

Following adjustment for sociodemographic and clinical factors, children exposed to FDV had an increased risk of hospitalisations for STIs (HR 1.49, 95% CI 1.15 to 1.92) and terminations of pregnancy (HR 1.34, 95% CI 1.09 to 1.63) as an adolescent than non-exposed peers.

CONCLUSION

Children exposed to FDV are at an increased risk of hospitalisation for STI and termination of pregnancy as an adolescent. Effective interventions are needed to support children exposed to FDV.

Numeracy and literacy attainment of children exposed to maternal incarceration and other adversities: A linked data study

Parental incarceration has been associated with educational disadvantages for children, such as lower educational attainment, increased grade retention, and truancy and suspensions. However, children exposed to parental incarceration often experience other adversities that are also associated with educational disadvantage; the contribution of these co-occurring adversities has not been considered in previous research. This study aimed to investigate the educational outcomes of children exposed to (a) maternal incarceration alone and (b) maternal incarceration plus other adversities (i.e., maternal mental illness and/or child protective services [CPS] contact). We used linked administrative data for a sample of children whose mothers were incarcerated during the children's childhood (i.e., from the time of mother's pregnancy through the child's 18th birthday; n = 3828) and a comparison group of children whose mothers had not been incarcerated (n = 9570). Multivariate multinomial logistic regressions examined the association between exposure to the three adversities (i.e., maternal incarceration, maternal mental illness, and child CPS contact) and above or below average reading and numeracy attainment in Grades 3, 5, 7 and 9. At all grade levels, children exposed to maternal incarceration alone and those exposed to maternal incarceration plus other adversities had increased odds of below average numeracy and reading attainment and decreased odds of above average numeracy and reading attainment compared to children without any of the recorded exposures. Children exposed to maternal incarceration and CPS contact and those exposed to all three adversities had increased odds of below average reading and numeracy attainment compared to children exposed to maternal incarceration alone. The findings highlight the complex needs of children of incarcerated mothers that must be considered when designing and delivering educational support programs. These children would benefit from the implementation of multi-tiered, trauma-informed educational and clinical services.

The lasting impact of family and domestic violence on neonatal health outcomes

OBJECTIVES

To compare the health of neonates born to women who experienced family and domestic violence (FDV) 12 months prior to birth, with the health of neonates born to women with an earlier history of FDV and women with no history of FDV.

METHODS

A retrospective cohort of women who experienced FDV within 12 months of birth (antenatal FDV [AFDV]) (n = 1230) was identified using data from the Western Australia (WA) Police Force Incident Management System and WA Hospital Morbidity Data Collection. Two comparison cohorts were used, the first including women with a history of FDV (HFDV) 12-60 months prior to birth (n = 1549) and the second with no history of FDV (NFDV) recorded (n = 3690). Hospital, birth, mortality, and congenital anomaly data were used in generalized linear models to examine and compare neonatal health outcomes.

RESULTS

Women in the AFDV group had higher proportions of factors associated with poor neonatal outcomes including smoking (42.4%), substance use (23.0%), and mental health disorders (34.8%). Neonates born to AFDV mothers had significantly higher odds of congenital anomalies (OR: 1.51, 95% CI: 1.18-1.94), low birth weight (1.74, 1.45-2.10), and preterm birth (1.48, 1.22-1.79) compared with neonates born to NFDV mother. Neonatal health outcomes in those born to AFDV women were not significantly different from those born to HFDV women.

CONCLUSIONS

Antenatal and historical FDV were associated with poor neonatal health outcomes. Additional pregnancy and social support should be offered to women who have experienced FDV during or prior to pregnancy.

Examining the relationship between maternal mental health-related hospital admissions and childhood developmental vulnerability at school entry in Canada and Australia

BACKGROUND

It is well established that maternal mental illness is associated with an increased risk of poor development for children. However, inconsistencies in findings regarding the nature of the difficulties children experience may be explained by methodological or geographical differences.

AIMS

We used a common methodological approach to compare developmental vulnerability for children whose mothers did and did not have a psychiatric hospital admission between conception and school entry in Manitoba, Canada, and Western Australia, Australia. We aimed to determine if there are common patterns to the type and timing of developmental difficulties across the two settings.

METHOD

Participants included children who were assessed with the Early Development Instrument in Manitoba, Canada (n = 69 785), and Western Australia, Australia (n = 19 529). We examined any maternal psychiatric hospital admission (obtained from administrative data) between conception and child's school entry, as well as at specific time points (pregnancy and each year until school entry).

RESULTS

Log-binomial regressions modelled the risk of children of mothers with psychiatric hospital admissions being developmentally vulnerable. In both Manitoba and Western Australia, an increased risk of developmental vulnerability on all domains was found. Children had an increased risk of developmental vulnerability regardless of their age at the time their mother was admitted to hospital.

CONCLUSIONS

This cross-national comparison provides further evidence of an increased risk of developmental vulnerability for children whose mothers experience severe mental health difficulties. Provision of preventative services during early childhood to children whose mothers experience mental ill health may help to mitigate developmental difficulties at school entry.

The influence of acculturation on the risk of preterm birth and low birthweight in migrant women residing in Western Australia

BACKGROUND

The risk of preterm birth (PTB) and low birthweight (LBW) may change over time the longer that immigrants reside in their adopted countries. We aimed to study the influence of acculturation on the risk of these outcomes in Australia.

METHODS

A retrospective cohort study using linked health data for all non-Indigenous births from 2005-2013 in Western Australia was undertaken. Acculturation was assessed through age on arrival, length of residence, interpreter use and having an Australian-born partner. Adjusted odds ratios (aOR) for term-LBW and PTB (all, spontaneous, medically-indicated) were calculated using multivariable logistic regression in migrants from six ethnicities (white, Asian, Indian, African, Māori, and 'other') for different levels of acculturation, compared to the Australian-born population as the reference.

RESULTS

The least acculturated migrant women, those from non-white non-Māori ethnic backgrounds who immigrated at age ≥18 years, had an overseas-born partner, lived in Australia for < 5 years and used a paid interpreter, had 58% (aOR 1.58, 95% CI 1.15-2.18) higher the risk of term-LBW and 40% (aOR 0.60, 95% CI 0.45-0.80) lower risk of spontaneous PTB compared to the Australian-born women. The most acculturated migrant women, those from non-white non-Māori ethnic backgrounds who immigrated at age <18 years, had an Australian-born partner, lived in Australia for > 10 years and did not use an interpreter, had similar risk of term-LBW but 43% (aOR 1.43, 95% CI 1.14-1.78) higher risk of spontaneous PTB than the Australian-born women.

CONCLUSION

Acculturation is an important factor to consider when providing antenatal care to prevent PTB and LBW in migrants. Acculturation may reduce the risk of term-LBW but, conversely, may increase the risk of spontaneous PTB in migrant women residing in Western Australia. However, the effect may vary by ethnicity and warrants further investigation to fully understand the processes involved.

Multigenerational health research using population-based linked databases: an international review

Family health history is a well-established risk factor for many health conditions but the systematic collection of health histories, particularly for multiple generations and multiple family members, can be challenging. Routinely-collected electronic databases in a select number of sites worldwide offer a powerful tool to conduct multigenerational health research for entire populations. At these sites, administrative and healthcare records are used to construct familial relationships and objectively-measured health histories. We review and synthesize published literature to compare the attributes of routinely-collected, linked databases for three European sites (Denmark, Norway, Sweden) and three non-European sites (Canadian province of Manitoba, Taiwan, Australian state of Western Australia) with the capability to conduct population-based multigenerational health research. Our review found that European sites primarily identified family structures using population registries, whereas non-European sites used health insurance registries (Manitoba and Taiwan) or linked data from multiple sources (Western Australia). Information on familial status was reported to be available as early as 1947 (Sweden); Taiwan had the fewest years of data available (1995 onwards). All centres reported near complete coverage of familial relationships for their population catchment regions. Challenges in working with these data include differentiating biological and legal relationships, establishing accurate familial linkages over time, and accurately identifying health conditions. This review provides important insights about the benefits and challenges of using routinely-collected, population-based linked databases for conducting population-based multigenerational health research, and identifies opportunities for future research within and across the data-intensive environments at these six sites.

Data Linkage in Australia: The First 50 Years

Population-based data linkage has a long history in Australia from its beginnings in Western Australia in the 1970s to the coordinated national data linkage infrastructure that exists today. This article describes the journey from an idea to a national data linkage network which has impacts on the health and well-being of Australians from preventing developmental anomalies to responding to the COVID-19 pandemic. Many enthusiastic and dedicated people have contributed to Australia's data linkage capability over the last 50 years. They have managed to overcome a number of challenges including gaining stakeholder and community support; navigating complex legal and ethical environments; establishing cross-jurisdictional collaborations, and gaining ongoing financial support. The future is bright for linked data in Australia as the infrastructure built over the last 50 years provides a firm foundation for further expansion and development, ensuring that Australia's linked health and human services data continues to be available to address the evolving challenges of the next half century.

Children with Secondary Care Episodes for Otitis Media Have Poor Literacy and Numeracy Outcomes: A Data Linkage Study

We examined the association between otitis media (OM) and educational attainment in a retrospective population cohort of Western Australian children who participated in the grade 3 National Assessment Program—Literacy and Numeracy in 2012 (N = 19,262). Literacy and numeracy scores were linked to administrative hospital and emergency department data to identify secondary care episodes for OM. Results of multivariate multilevel models showed that children with OM episodes had increased odds of poor performance on literacy and numeracy tests, compared to children without OM episodes (46–79% increase in odds for Aboriginal children; 20–31% increase in odds for non-Aboriginal children). There were no significant effects found for age at the first episode, nor for OM episode frequency (all ps > 0.05). Regardless of the timing or frequency of episodes, children with OM episodes are at risk of poor literacy and numeracy attainment. Aboriginal children with OM appeared to be particularly at risk of poor literacy and numeracy achievement. Intervention to reduce the prevalence of otitis media in young children, and early treatment of OM, are important for limiting the negative effects on academic outcomes.

A comparison of trajectories of offending among people with psychotic disorders, other mental disorders and no mental disorders: Evidence from a whole-of-population birth cohort study

BACKGROUND

Trajectory analysis has been used to study long-term offending patterns and identify offender subgroups, but few such studies have included people with psychotic disorders (PDs) and these have been restricted to adult offenders.

AIMS

To compare offending trajectories among 10-26-year-olds with PDs with those with other mental disorders (OMDs) or none (NMD) and identify associated risk factors.

METHODS

This is a record-linkage study of 184,147 people born in Western Australia (WA) 1983-1991, drawing on data from WA mental health information system, WA corrective services and other state-wide registers. Group-based trajectory modelling was used to identify offending trajectories.

RESULTS

Four offender groups were identified in each mental health status group: G1-no/negligible offending; G2-early onset, adolescent, desisting by age 18; G3-early onset, low rate, offending into early adulthood; and G4-very early onset, high rate, peaking at age 17, continuing into early adulthood. The PDs group had the lowest proportion of individuals with no or negligible offending histories-84% compared with 88.5% in the OMDs group and 96.6% in the no mental disorder group. Within mental health status offender groups, the PDs group was characterised by early or very early onset offending persisting into adulthood, accounting for 5.4% and 3.7% of the group respectively (OMD: 3.8%, 1.5%; NMD: 1.0%, 0.5%). Gender, indigenous status, substance use problems, childhood abuse and parental offending were generally associated with trajectory group membership, although among those with PDs childhood abuse and parental offending were only significant in the early onset-life-course-persistent group.

CONCLUSIONS

While most people with PDs never offend, some are disproportionately vulnerable from a particularly early age. If the offending subgroup is to be helped away from criminal justice involvement, interventions must be considered in childhood.

The familial risk of infection-related hospitalization in children: A population-based sibling study

Objective

To assess the risk of severe childhood infections within families, we conducted a sibling analysis in a population-based cohort study with genealogical linkage. We investigated the sibling risk of hospitalization with common infections, a marker of severity. We hypothesized that having siblings hospitalized for infection would increase the proband’s risk of admission with infection.

Study design

We used population data on Western Australian live-born singletons and their siblings between 1980 and 2014. Measures of infection were infection-related hospitalizations from discharge diagnostic codes. Exposure was having a sibling who had an infection-related hospitalization. Outcomes were infection-related hospitalizations in the child/proband. Probands were followed until an infection-related hospitalization admission (up to the first three), death, 18th birthday, or end of 2014, whichever occurred first. Infection risks were estimated by adjusted Cox proportional hazard models for multiple events.

Results

Of 512,279 probands, 142,915 (27.9%) had infection-related hospitalizations; 133,322 (26.0%) had a sibling with a previous infection-related hospitalization (i.e. exposed). Median interval between sibling and proband infection-related hospitalizations was 1.4 years (inter-quartile range 0.5–3.7). Probands had a dose-dependent increase in risk if sibling/s had 1, 2, or 3+ infection-related hospitalizations (adjusted hazard ratio, aHR 1.41, 95% CI 1.39–1.43; aHR 1.65, 1.61–1.69; aHR 1.83, 1.77–1.90, respectively). Among siblings with the same clinical infection type, highest sibling risks were for genitourinary (aHR 2.06, 1.68–2.53), gastrointestinal (aHR 2.07, 1.94–2.19), and skin/soft tissue infections (aHR 2.34, 2.15–2.54). Overall risk of infection-related hospitalization was higher in children with more siblings and with older siblings.

Conclusion

In this population-based study, we observed an increased risk of infection-related hospitalization in children whose siblings were previously hospitalized for infection. Public health interventions may be particularly relevant in families of children hospitalized with infection.

The influence of acculturation on the risk of stillbirth in migrant women residing in Western Australia

Objective

To investigate the influence of acculturation, demonstrated by age on arrival, length of residence, interpreter use and having an Australian-born partner, on disparities observed in the risk of stillbirth between migrant and Australian-born populations in Western Australia (WA).

Methods

A retrospective cohort study using linked administrative health data for all non-Indigenous births in WA from 2005–2013 was performed. Logistic regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Adjusted odds ratios (aOR) for stillbirth in migrants from six ethnicities of white, Asian, Indian, African, Māori, and ‘other’, with different levels of acculturation, were compared with Australian-born women using multivariable logistic regression analysis and marital status, maternal age group, socioeconomic status, parity, plurality, previous stillbirth, any medical conditions, any pregnancy complications, sex of baby, and smoking during pregnancy as the covariates.

Results

From all births studied, 172,571 (66%) were to Australian-born women and 88,395 (34%) to migrant women. Women from African, Indian and Asian backgrounds who gave birth in the first two years after arrival in Australia experienced the highest risk of stillbirth (aOR 3.32; 95% CI 1.70–6.47, aOR 2.71; 95% CI 1.58–4.65, aOR 1.93; 95% CI 1.21–3.05 respectively) compared with Australian-born women. This association attenuated with an increase in the length of residence in Asian and Indian women, but the risk of stillbirth remained elevated in African women after five years of residence (aOR 1.96 [1.10–3.49]). Interpreter use and an Australian-born partner were associated with 56% and 20% lower odds of stillbirth in migrants (p<0.05), respectively.

Conclusions

Acculturation is a multidimensional process and may lower the risk of stillbirth through better communication and service utilisation and elevate such risk through increase in prevalence of smoking in pregnancy; the final outcome depends on how these factors are in play in a population. It is noteworthy that in women of African background risk of stillbirth remained elevated for longer periods after immigrating to Australia extending beyond five years. For migrants from Asian and Indian backgrounds, access to services, in the first two years of residence, may be more relevant. Enhanced understanding of barriers to accessing health services and factors influencing and influenced by acculturation may help developing interventions to reduce the burden of stillbirth in identified at-risk groups.

Identifying young Aboriginal and Torres Strait Islander children in linked administrative data: A comparison of methods

Background

In the ongoing debate on optimum methods for identification of Indigenous people within linked administrative data, few studies have examined the impacts of method on population counts and outcomes in family-based linkage studies of Aboriginal children.

Objective

To quantify differences between three algorithms in ascertaining Aboriginal and Torres Strait Islander children in linked administrative data.

Methods

Linked administrative health data for children born in Western Australia (WA) from 2000-2013, were used to examine the cohorts identified by three methods: A) the Indigenous Status Flag (ISF, derived by the WA Data Linkage Branch using a multistage-median approach) for the children alone; B) the ISF of the children, their parents and grandparents; and C) Indigenous status of the child, mother or father on either of the child's perinatal records (Midwives or birth registration), to determine differing characteristics of each cohort.

Results

Method B established a larger cohort (33,489) than Method C (33,306) and Method A (27,279), with all methods identifying a core group of 26,790 children (80-98%). Compared with children identified by Method A, additional children identified by Methods B or C, were from less-disadvantaged and more urban areas, and had better perinatal outcomes (e.g. lower proportions of small-for-gestational age, 10% vs 16%). Differences in demographics and health outcomes between Methods C and B were minimal.

Conclusions

Demographic and perinatal health characteristics differ by Aboriginal identification method. Using perinatal records or the ISF of parents and grandparents (in addition to the ISF of the child) appear to be more inclusive methods for identifying young Indigenous children in administrative datasets.

Keywords

Aboriginal health, identification, data linkage, Indigenous, child, methodology.

Healthcare factors associated with the risk of antepartum and intrapartum stillbirth in migrants in Western Australia (2005-2013): A retrospective cohort study

BACKGROUND

Migrant women, especially from Indian and African ethnicity, have a higher risk of stillbirth than native-born populations in high-income countries. Differential access or timing of ANC and the uptake of other services may play a role. We investigated the pattern of healthcare utilisation among migrant women and its relationship with the risk of stillbirth (SB)-antepartum stillbirth (AnteSB) and intrapartum stillbirth (IntraSB)-in Western Australia (WA).

METHODS AND FINDINGS

A retrospective cohort study using de-identified linked data from perinatal, birth, death, hospital, and birth defects registrations through the WA Data Linkage System was undertaken. All (N = 260,997) non-Indigenous births (2005-2013) were included. Logistic regression analysis was used to estimate odds ratios and 95% CI for AnteSB and IntraSB comparing migrant women from white, Asian, Indian, African, Māori, and 'other' ethnicities with Australian-born women controlling for risk factors and potential healthcare-related covariates. Of all the births, 66.1% were to Australian-born and 33.9% to migrant women. The mean age (years) was 29.5 among the Australian-born and 30.5 among the migrant mothers. For parity, 42.3% of Australian-born women, 58.2% of Indian women, and 29.3% of African women were nulliparous. Only 5.3% of Māori and 9.2% of African migrants had private health insurance in contrast to 43.1% of Australian-born women. Among Australian-born women, 14% had smoked in pregnancy whereas only 0.7% and 1.9% of migrants from Indian and African backgrounds, respectively, had smoked in pregnancy. The odds of AnteSB was elevated in African (odds ratio [OR] 2.22, 95% CI 1.48-2.13, P < 0.001), Indian (OR 1.64, 95% CI 1.13-2.44, P = 0.013), and other women (OR 1.46, 95% CI 1.07-1.97, P = 0.016) whereas IntraSB was higher in African (OR 5.24, 95% CI 3.22-8.54, P < 0.001) and 'other' women (OR 2.18, 95% CI 1.35-3.54, P = 0.002) compared with Australian-born women. When migrants were stratified by timing of first antenatal visit, the odds of AnteSB was exclusively increased in those who commenced ANC later than 14 weeks gestation in women from Indian (OR 2.16, 95% CI 1.18-3.95, P = 0.013), Māori (OR 3.03, 95% CI 1.43-6.45, P = 0.004), and 'other' (OR 2.19, 95% CI 1.34-3.58, P = 0.002) ethnicities. With midwife-only intrapartum care, the odds of IntraSB for viable births in African and 'other' migrants (combined) were more than 3 times that of Australian-born women (OR 3.43, 95% CI 1.28-9.19, P = 0.014); however, with multidisciplinary intrapartum care, the odds were similar to that of Australian-born group (OR 1.34, 95% CI 0.30-5.98, P = 0.695). Compared with Australian-born women, migrant women who utilised interpreter services had a lower risk of SB (OR 0.51, 95% CI 0.27-0.96, P = 0.035); those who did not utilise interpreters had a higher risk of SB (OR 1.20, 95% CI 1.07-1.35, P < 0.001). Covariates partially available in the data set comprised the main limitation of the study.

CONCLUSION

Late commencement of ANC, underutilisation of interpreter services, and midwife-only intrapartum care are associated with increased risk of SB in migrant women. Education to improve early engagement with ANC, better uptake of interpreter services, and the provision of multidisciplinary-team intrapartum care to women specifically from African and 'other' backgrounds may reduce the risk of SB in migrants.

Familial and non-familial risk factors associated with incidence of colorectal cancer in young and middle-aged persons in Western Australia

AIMS

The aim of this study was to examine factors including family history, medical history and comorbidities associated with the risk of colorectal cancer (CRC) in young (18-49 years) and middle-age (50-69 years) individuals.

METHODS

State records were used to identify individuals born in Western Australia between 1945 and 1996, and their first-degree relatives. Individuals in the cohort and their relatives were linked to State cancer registry, hospital and mortality data to identify diagnoses of CRC and other risk factors. The associations between CRC and identified risk factors were examined using multivariable logistic regression.

RESULTS

For both young and middle-aged patients, family history of CRC, and a history of smoking, inflammatory bowel disease, liver disease and non-CRC cancer were associated with a significant increase in odds of CRC. In middle-aged patients, having a colonoscopy in the previous 10 years was associated with a reduced odds of CRC regardless of the detection of polyps. However, in young patients only the absence of polyps as confirmed by colonoscopy was associated with a decreased risk of CRC (OR: 0.38, 95%CI: 0.26 - 0.54, p < 0.001).

CONCLUSIONS

Many of the risk factors associated with CRC were similar in young and middle-aged persons, and should be used to identify high risk young patients for screening. The association between colonoscopy and polyps with CRC was modified by age, likely as the result of routine screening in middle-aged patients.

Recurrence Risk of Autism in Siblings and Cousins: A Multinational, Population-Based Study

OBJECTIVE

Familial recurrence risk is an important population-level measure of the combined genetic and shared familial liability of autism spectrum disorder (ASD). Objectives were to estimate ASD recurrence risk among siblings and cousins by varying degree of relatedness and by sex.

METHOD

This is a population-based cohort study of livebirths from 1998 to 2007 in California, Denmark, Finland, Israel, Sweden and Western Australia followed through 2011 to 2015. Subjects were monitored for an ASD diagnosis in their older siblings or cousins (exposure) and for their ASD diagnosis (outcome). The relative recurrence risk was estimated for different sibling and cousin pairs, for each site separately and combined, and by sex.

RESULTS

During follow-up, 29,998 cases of ASD were observed among the 2,551,918 births used to estimate recurrence in ASD and 33,769 cases of childhood autism (CA) were observed among the 6,110,942 births used to estimate CA recurrence. Compared with the risk in unaffected families, there was an 8.4-fold increase in the risk of ASD following an older sibling with ASD and a 17.4-fold increase in the risk of CA following an older sibling with CA. A 2-fold increase in the risk for cousin recurrence was observed for the 2 disorders. There also was a significant difference in sibling ASD recurrence risk by sex.

CONCLUSION

The present estimates of relative recurrence risks for ASD and CA will assist clinicians and families in understanding autism risk in the context of other families in their population. The observed variation by sex underlines the need to deepen the understanding of factors influencing ASD familial risk.

A large proportion of poor birth outcomes among Aboriginal Western Australians are attributable to smoking, alcohol and substance misuse, and assault

Background

Aboriginal infants have poorer birth outcomes than non-Aboriginal infants. Harmful use of tobacco, alcohol, and other substances is higher among Aboriginal women, as is violence, due to factors such as intergenerational trauma and poverty. We estimated the proportion of small for gestational age (SGA) births, preterm births, and perinatal deaths that could be attributed to these risks.

Methods

Birth, hospital, mental health, and death records for Aboriginal singleton infants born in Western Australia from 1998 to 2010 and their parents were linked. Using logistic regression with a generalized estimating equation approach, associations with birth outcomes and population attributable fractions were estimated after adjusting for demographic factors and maternal health during pregnancy.

Results

Of 28,119 births, 16% of infants were SGA, 13% were preterm, and 2% died perinatally. 51% of infants were exposed in utero to at least one of the risk factors and the fractions attributable to them were 37% (SGA), 16% (preterm) and 20% (perinatal death).

Conclusions

A large proportion of adverse outcomes were attributable to the modifiable risk factors of substance use and assault. Significant improvements in Aboriginal perinatal health are likely to follow reductions in these risk factors. These results highlight the importance of identifying and implementing risk reduction measures which are effective in, and supported by, Aboriginal women, families, and communities.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2252-4) contains supplementary material, which is available to authorized users.

Exploring factors impacting early childhood health among Aboriginal and Torres Strait Islander families and communities: protocol for a population-based cohort study using data linkage (the 'Defying the Odds' study)

INTRODUCTION

Empirical evidence on family and community risk and protective factors influencing the comparatively high rates of potentially preventable hospitalisations and deaths among Aboriginal and Torres Strait Islander infants and children is limited. As is evidence on geographical variation in these risks. The 'Defying the Odds' study aims to explore the impact of perinatal outcomes, maternal social and health outcomes and level of culturally secure service availability on the health outcomes of Western Australian (WA) Aboriginal infants and children aged 0-5 years.

METHODS AND ANALYSIS

The study combines a retrospective cohort study that uses state-wide linked health and administrative data from 12 data sources for multiple generations within Aboriginal families in WA, with specifically collected survey data from health and social services supporting Aboriginal families in regions of WA. Data sources include perinatal/birth registration, hospital, emergency department, mental health services, drug and alcohol service use, mortality, infectious disease notifications, and child protection and family services. Multilevel regression models will be used to examine the intensity of admissions and presentations, mortality, intensity of long stays and morbidity-free survival (no admissions) for Aboriginal children born in WA in 2000-2013. Relationships between maternal (and grand-maternal) health and social factors and child health outcomes will be quantified. Community-level variation in outcomes for Aboriginal children and factors contributing to this variation will be examined, including the availability of culturally secure services. Online surveys were sent to staff members at relevant services to explore the scope, reach and cultural security of services available to support Aboriginal families across selected regions of WA.

ETHICS AND DISSEMINATION

Ethics approvals have been granted for the study. Interpretation and dissemination are guided by the study team's Aboriginal leadership and reference groups. Dissemination will be through direct feedback and reports to health services in the study and via scientific publications and policy recommendations.

Use of prescription stimulant for Attention Deficit Hyperactivity Disorder in Aboriginal children and adolescents: a linked data cohort study

BACKGROUND

Increasing recognition of Attention Deficit Hyperactivity Disorder (ADHD) among Aboriginal children, adolescents and young adults is a public health challenge. We investigated the pattern of prescription stimulants for ADHD among Aboriginal individuals in Western Australia (WA).

METHODS

Using a whole-population-based linked data we followed a cohort of individuals born in WA from 1980-2005, and their parents were born in Australia, to identify stimulant prescription for ADHD derived from statutory WA stimulant prescription dispensing between 2003 and 2007. Parental link was ascertained through WA Family Connections Genealogical Linkage System. Cox proportional hazards regression (HR) models were performed to determine the association between stimulant use and Aboriginal and non-Aboriginal status.

RESULTS

Of the total cohort of 186,468, around 2% (n = 3677) had prescription stimulants for ADHD. Individuals with both Aboriginal parents were two-thirds (HR 0.33, 95 % CI 0.26-0.42), and with only Aboriginal mother were one-third (HR 0.69, 95% CI 0.53-0.90) less likely to have stimulants, compared to individuals with non-Aboriginal parents. HR in Aboriginals was 62% lower (HR 0.35, 95% CI 0.25-0.49) in metropolitan areas, and 72% lower (HR 0.28, 95% CI 0.20-0.38) in non-metropolitan areas, than non-Aboriginals. The risk for simulant use was four times higher among Aboriginal boys than Aboriginal girls (HR 4.08, 95% CI, 2.92-5.69).

CONCLUSION

Aboriginal cultural understanding of ADHD and attitude towards stimulant medication serve as a determinant of their access to health services. Any ADHD intervention and policy framework must take into account a holistic approach to Aboriginal culture, beliefs and individual experience to provide optimal care they need.

The aggregation of early-onset melanoma in young Western Australian families

BACKGROUND

Few studies have examined the familial aggregation of melanoma or its co-aggregation with other cancers using whole-population based designs. This study aimed to investigate aggregation patterns in young Western Australian families, using population-based linked health data to identify individuals born in Western Australia between 1974 and 2007, their known relatives, and all incident cancer diagnoses within the resulting 1,506,961 individuals.

METHODS

Cox proportional hazards regression models were used to compare the risk of melanoma for first-degree relatives of melanoma cases to that for first-degree relatives of controls, with bootstrapping used to account for correlations within families. The risk of (i) developing melanoma based on the number of first-degree relatives with other cancers, and (ii) developing non-melanoma cancers based on the number of first-degree relatives diagnosed with melanoma was also investigated.

RESULTS

First-degree relatives of melanoma cases had a significantly greater incidence of melanoma than first-degree relatives of individuals not affected with melanoma (Hazard Ratio (HR)=3.58, 95% bootstrap confidence interval (CI): 2.43-5.43). Sensitivity analyses produced a higher hazard ratio estimate when restricted to melanoma cases diagnosed before 40 years of age (HR=3.77, bootstrap 95% CI: 2.49-6.39) and a lower estimate when only later-onset cases (>40 years) were considered (HR=2.45, bootstrap 95% CI: 1.23-4.82). No significant evidence was found for co-aggregation between melanoma and any other cancers.

CONCLUSIONS

Results indicated a strong familial basis of melanoma, with the higher than expected hazard ratio observed likely to reflect early-age at onset cases in this young cohort, supported by the results of the sensitivity analyses. Exploratory analyses suggested that the determinants of melanoma causing the observed aggregation within families may be independent of other malignancies, although these analyses were limited by the young age of the sample. Determining familial aggregation patterns will provide valuable knowledge regarding improved clinical risk prediction and the underlying biological mechanisms of melanoma and other cancers.

Intellectual disability and other neuropsychiatric outcomes in high-risk children of mothers with schizophrenia, bipolar disorder and unipolar major depression

BACKGROUND

Recent evidence points to partially shared genetics of neuropsychiatric disorders.

AIMS

We examined risk of intellectual disability and other neuropsychiatric outcomes in 3174 children of mothers with schizophrenia, bipolar disorder or unipolar major depression compared with 3129 children of unaffected mothers.

METHOD

We used record linkage across Western Australian population-based registers. The contribution of obstetric factors to risk of intellectual disability was assessed.

RESULTS

Children were at significantly increased risk of intellectual disability with odds ratios (ORs) of 3.2 (95% CI 1.8-5.7), 3.1 (95% CI 1.9-4.9) and 2.9 (95% CI 1.8-4.7) in the maternal schizophrenia, bipolar disorder and unipolar depression groups respectively. Multivariate analysis suggests familial and obstetric factors may contribute independently to the risk. Although summated labour/delivery complications (OR = 1.4, 95% CI 1.0-2.0) just failed to reach significance, neonatal encephalopathy (OR = 7.7, 95% CI 3.0-20.2) and fetal distress (OR = 1.8, 95% CI 1.1-2.7) were independent significant predictors. Rates of rare syndromes in children of mothers with mental disorder were well above population rates. Risk of pervasive developmental disorders, including autism, was significantly elevated for children of mothers with bipolar disorder. Risk of epilepsy was doubled for children of mothers with unipolar depression.

CONCLUSIONS

Our findings provide epidemiological support for clustering of neuropsychiatric disorders. Further larger epidemiological studies are warranted.

Hospitalisation with infection, asthma and allergy in Kawasaki disease patients and their families: genealogical analysis using linked population data

BACKGROUND

Kawasaki disease results from an abnormal immunological response to one or more infectious triggers. We hypothesised that heritable differences in immune responses in Kawasaki disease-affected children and their families would result in different epidemiological patterns of other immune-related conditions. We investigated whether hospitalisation for infection and asthma/allergy were different in Kawasaki disease-affected children and their relatives.

METHODS/MAJOR FINDINGS

We used Western Australian population-linked health data from live births (1970-2006) to compare patterns of hospital admissions in Kawasaki disease cases, age- and sex-matched controls, and their relatives. There were 295 Kawasaki disease cases and 598 age- and sex-matched controls, with 1,636 and 3,780 relatives, respectively. Compared to controls, cases were more likely to have been admitted at least once with an infection (cases, 150 admissions (50.8%) vs controls, 210 admissions (35.1%); odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.4-2.6, P = 7.2×10⁻⁶), and with asthma/allergy (cases, 49 admissions (16.6%) vs controls, 42 admissions (7.0%); OR = 2.6, 95% CI 1.7-4.2, P = 1.3×10⁻⁵). Cases also had more admissions per person with infection (cases, median 2 admissions, 95% CI 1-5, vs controls, median 1 admission, 95% CI 1-4, P = 1.09×10⁻⁵). The risk of admission with infection was higher in the first degree relatives of Kawasaki disease cases compared to those of controls, but the differences were not significant.

CONCLUSION

Differences in the immune phenotype of children who develop Kawasaki disease may influence the severity of other immune-related conditions, with some similar patterns observed in relatives. These data suggest the influence of shared heritable factors in these families.

Administrative record linkage as a tool for public health research

Linked administrative databases offer a powerful resource for studying important public health issues. Methods developed and implemented in several jurisdictions across the globe have achieved high-quality linkages for conducting health and social research without compromising confidentiality. Key data available for linkage include health services utilization, population registries, place of residence, family ties, educational outcomes, and use of social services. Linking events for large populations of individuals across disparate sources and over time permits a range of research possibilities, including the capacity to study low-prevalence exposure-disease associations, multiple outcome domains within the same cohort of individuals, service utilization and chronic disease patterns, and life course and transgenerational transmission of health. Limited information on variables such as individual-level socioeconomic status (SES) and social supports is outweighed by strengths that include comprehensive follow-up, continuous data collection, objective measures, and relatively low expense. Ever advancing methodologies and data holdings guarantee that research using linked administrative databases will make increasingly important contributions to public health research.

Linked data: opportunities and challenges in disability research

BACKGROUND

Disability research data often exist in the form of individual records located within discrete registers that may extend across sensitive political boundaries.

METHOD

This paper discusses the opportunities and challenges associated with using linked health and administrative data for disability research, with examples from research projects conducted both in Australia and overseas.

RESULTS

Linked data offer distinct value in providing a comprehensive profile for a range of health issues, such as morbidity, mortality, assessing health care costs and/or quality of service provision.

CONCLUSIONS

While the use of record linkage in health research is not a novel concept, recent advances in technology and electronic data management plus improved data linkage protocols have markedly increased the feasibility and opportunity for successfully utilising data linkage for the purposes of research, while at the same time protecting the privacy of the individual. An awareness and appropriate management of the associated challenges is required to maximise the outcomes of disability research using linked data.