Objectively measured infant and toddler screen time: Findings from a prospective study.

Objective: Screen time guidelines recommend no screens under two years due to the potential negative impacts on development. While current reports suggest many children exceed this, research relies on parent reports of their children's screen exposure. We objectively assess screen exposure during the first two years and how it differs by maternal education and gender. Methods: This Australian prospective cohort study used speech recognition technology to understand young children's screen exposure over an average day. Data collection occurred every six months when children were 6, 12, 18 and, 24 months old (n = 207). The technology provided automated counts of children's exposure to electronic noise. Audio segments were then coded as screen exposure. Prevalence of screen exposure was quantified, and differences between demographics examined. Results: At six months, children were exposed to an average of 1hr, 16 min (SD = 1hr, 36 min) of screens per day, increasing to an average of 2 h, 28 min (SD = 2 h, 4 min) by 24-months. Some children at six months were exposed to more than 3 h of screen time per day. Inequalities in exposure were evident as early as six months. Children from higher educated families were exposed to 1hr,43 min fewer screens per day, 95%CI (-2hr, 13 min, -1hr, 11 min) compared to lower educated households, with this difference remaining consistent as children age. Girls were exposed to an additional 12 min of screens 95%CI (-20 min, 44 min) per day compared to boys at six months, but this difference reduced to only 5 min by 24-months. Conclusion: Using an objective measure of screen exposure, many families exceed screen time guidelines, the extent increasing with child's age. Furthermore, substantial differences between maternal education groups emerge as young as six months old. This highlights the need for education and supports for parents around screen use in the early years, balanced within the realities of modern life.

Application of multilevel models for predicting pain following root canal treatment.

OBJECTIVES: This study developed predictive models for one-week acute and six-month persistent pain following root canal treatment (RCT). An additional aim was to study the gain in predictive efficacy of models containing clinical factors only, over models containing sociodemographic characteristics. METHODS: A secondary data analysis of 708 patients who received RCTs was conducted. Three sets of predictors were used: (1) combined set, containing all predictors in the data set; (2) clinical set and (3) sociodemographic set. Missing data were handled by multiple imputation using the missing indicator method. The multilevel least absolute selection and shrinkage operator (LASSO) regression was used to select predictors into the final multilevel logistic models. Three measures, the area under the receiver operating characteristic curve (AUROC) and precision-recall curve (AUPRC) and calibration curves, were used to assess the predictive performance of the models. RESULTS: The selected-in factors in the final models, using LASSO regression, are related to pre- and intra-treatment clinical symptoms and pain experience. Predictive performance of the models remained the same with the inclusion (exclusion) of the socio-demographic factors. For predicting one-week outcome, the model built with combined set of predictors yielded the highest AUROC and AUPRC of 0.85 and 0.72, followed by the models built with clinical factors (AUROC = 0.82, AUPRC = 0.66). The lowest predictive ability was found in models with only sociodemographic characteristics (AUROC = 0.68, AUPRC = 0.40). Similar patterns were observed in predicting six-month outcome, where the AUROC for models with combined, clinical and sociodemographic sets of predictors were 0.85, 0.89 and 0.66, respectively, and the AUPRC were 0.48, 0.53 and 0.22, respectively. CONCLUSIONS: Clinical factors such as the severity and experience of pre-operative and intra-operative pain were discovered important to the subsequent development of pain following RCTs. Adding sociodemographic characteristics to the models with clinical factors did not change the models' predictive performance or the proportion of explained variance.

Smoking cessation care during pregnancy: A qualitative exploration of midwives' challenging role.

PROBLEM: The majority of South Australian pregnant women who smoke do not quit during pregnancy. Additionally, the prevalence of smoking is higher among pregnant women living in socially disadvantaged areas. BACKGROUND: Understanding challenges in midwives' provision of smoking cessation care can elucidate opportunities to facilitate women's smoking cessation. AIM: We aimed to understand midwives' perspectives on current practices, perceived barriers and facilitators to delivery of smoking cessation care, and potential improvements to models of smoking cessation care. METHODS: An exploratory qualitative research methodology and thematic analysis was used to understand the perspectives of midwives in five focus groups. FINDINGS: Four themes were generated from the data on how midwives perceived their ability to provide smoking cessation care: Tensions between providing smoking cessation care and maternal care; Organisational barriers in the delivery of smoking cessation care; Scepticism and doubt in the provision of smoking cessation care; and Opportunities to enable midwives' ability to provide smoking cessation care. DISCUSSION: A combination of interpersonal, organisational and individual barriers impeded on midwives' capacities to approach, follow-up and prioritise smoking cessation care. Working with women living with disadvantage and high rates of smoking, the midwife's role was challenging as it balanced delivering smoking cessation care without jeopardising antenatal care. CONCLUSION: Providing midwives with resources and skills may alleviate the sense of futility that surrounds smoking cessation care. Provision of routine training and education could also improve understandings of the current practice guidelines.

Emulating a target trial of intensive nurse home visiting in the policy-relevant population using linked administrative data.

BACKGROUND: Populations willing to participate in randomized trials may not correspond well to policy-relevant target populations. Evidence of effectiveness that is complementary to randomized trials may be obtained by combining the 'target trial' causal inference framework with whole-of-population linked administrative data. METHODS: We demonstrate this approach in an evaluation of the South Australian Family Home Visiting Program, a nurse home visiting programme targeting socially disadvantaged families. Using de-identified data from 2004-10 in the ethics-approved Better Evidence Better Outcomes Linked Data (BEBOLD) platform, we characterized the policy-relevant population and emulated a trial evaluating effects on child developmental vulnerability at 5 years (n = 4160) and academic achievement at 9 years (n = 6370). Linkage to seven health, welfare and education data sources allowed adjustment for 29 confounders using Targeted Maximum Likelihood Estimation (TMLE) with SuperLearner. Sensitivity analyses assessed robustness to analytical choices. RESULTS: We demonstrated how the target trial framework may be used with linked administrative data to generate evidence for an intervention as it is delivered in practice in the community in the policy-relevant target population, and considering effects on outcomes years down the track. The target trial lens also aided in understanding and limiting the increased measurement, confounding and selection bias risks arising with such data. Substantively, we did not find robust evidence of a meaningful beneficial intervention effect. CONCLUSIONS: This approach could be a valuable avenue for generating high-quality, policy-relevant evidence that is complementary to trials, particularly when the target populations are multiply disadvantaged and less likely to participate in trials.

The Hospital Burden Associated With Intergenerational Contact With the Welfare System in Australia.

Importance: Intergenerational welfare contact is a policy issue because of the personal and social costs of entrenched disadvantage; yet, few studies have quantified the burden associated with intergenerational welfare contact for health. Objective: To examine the proportion of individuals who experienced intergenerational welfare contact and other welfare contact types and to estimate their cause-specific hospital burden. Design, Setting, and Participants: This cohort study used a whole-of-population linked administrative dataset of individuals followed from birth to age 20 years using deidentified data from the Better Evidence Better Outcomes Linked Data platform (Australian Government Centrelink [welfare payments], birth registration, perinatal birth records, and inpatient hospitalizations). Participants included individuals born in South Australia from 1991 to 1995 and their parents. Analysis was undertaken from January 2020 to June 2022. Exposures: Using Australian Government Centrelink data, welfare contact was defined as 1 or more parents receiving a means-tested welfare payment (low-income, unemployment, disability, or caring) when children were aged 11 to 15 years, or youth receiving payment at ages 16 to 20 years. Intergenerational welfare contact was defined as welfare contact occurring in both parent and offspring generations. Offspring were classified as: no welfare contact, parent-only welfare contact, offspring-only welfare contact, or intergenerational welfare contact. Main Outcomes and Measures: Hospitalization rates and cumulative incidence were estimated by age, hospitalization cause, and welfare contact group. Results: A total of 94 358 offspring (48 589 [51.5%] male) and 143 814 parents were included in analyses. The study population included 32 969 offspring (34.9%) who experienced intergenerational welfare contact. These individuals were more socioeconomically disadvantaged at birth and had the highest hospitalization rate (133.5 hospitalizations per 1000 person-years) compared with individuals with no welfare contact (46.1 hospitalizations per 1000 person-years), individuals with parent-only welfare contact (75.0 hospitalizations per 1000 person-years), and individuals with offspring-only welfare contact (87.6 hospitalizations per 1000 person-years). Hospitalizations were frequently related to injury, mental health, and pregnancy. For example, the proportion of individuals with intergenerational welfare contact who had experienced at least 1 hospitalization at ages 16 to 20 years was highest for injury (9.0% [95% CI, 8.7%-9.3%]). Conclusions and Relevance: In this population-based cohort study, individuals who experienced intergenerational welfare contact represented one-third of the population aged 11 to 20 years. Compared with individuals with parent-only welfare contact, individuals with intergenerational welfare contact were more disadvantaged at birth and had 78% higher hospitalization rates from age 11 to 20 years, accounting for more than half of all hospitalizations. Frequent hospitalization causes were injuries, mental health, and pregnancy. This study provides the policy-relevant estimate for what it could mean to break cycles of disadvantage for reducing hospital burden.

Examining the intersection of child protection and public housing: development, health and justice outcomes using linked administrative data.

OBJECTIVE: We described development, health and justice system outcomes for children in contact with child protection and public housing. DESIGN: Descriptive analysis of outcomes for children known to child protection who also had contact with public housing drawn from the South Australian (SA) Better Evidence Better Outcomes Linked Data (BEBOLD) platform. SETTING: The BEBOLD platform holds linked administrative records collected by government agencies for whole-population successive birth cohorts in SA beginning in 1999. PARTICIPANTS: This study included data from birth registrations, perinatal, child protection, public housing, hospital, emergency department, early education and youth justice for all SA children born 1999-2013 and followed until 2016. The base population notified at least once to child protection was n=67 454. PRIMARY OUTCOME MEASURE: Contact with the public housing system. SECONDARY OUTCOME MEASURES: Hospitalisations and emergency department presentations before age 5, and early education at age 5, and youth justice contact before age 17. RESULTS: More than 60% of children with at least one notification to child protection had contact with public housing, and 60.2% of those known to both systems were known to housing first. Children known to both systems experienced more emergency department and hospitalisation contacts, greater developmental vulnerability and were about six times more likely to have youth justice system contact. CONCLUSIONS: There is substantial overlap between involvement with child protection and public housing in SA. Those children are more likely to face a life trajectory characterised by greater contact with the health system, greater early life developmental vulnerability and greater contact with the criminal justice system. Ensuring the highest quality of supportive early life infrastructure for families in public housing may contribute to prevention of contact with child protection and better life trajectories for children.

Characteristics of paediatric frequent presenters at emergency departments: A whole-of-population study.

AIM: To quantify the frequency of emergency department (ED) presentations and profile the socio-demographic, health and presentation characteristics of paediatric ED frequent presenters. METHODS: A population-based data linkage study of 55 921 children in the South Australian Early Childhood Data Project aged 0-12 years with 100 976 presentations to public hospital EDs in South Australia. For each child, the total number of recurrent ED presentations during a 364-day period post-index presentation was calculated. Frequent presenters were children who experienced ≥4 recurrent ED presentations. We determined the socio-demographic, health and presentation characteristics by number of recurrent presentations. RESULTS: Children with ≥4 recurrent presentations (4.4%) accounted for 15.4% of all paediatric ED presentations and 22.5% of subsequent admissions to hospital during the 12-month study period. Compared to children with no recurrent ED presentation, frequent presenters had higher proportions of socio-economic and health disadvantage at birth. One in two (49.3%) frequent presenters had at least one injury presentation and one (21.3%) in five had at least one presentation related to a chronic condition. CONCLUSIONS: Children with ≥4 presentations do not represent the majority of ED users. Nevertheless, they represent a disproportionate burden accounting for 15% of all paediatric ED presentations in a 12-month period. Frequent presenters were characterised by early socio-economic and health disadvantage, and childhood injury. Strategies targeting social disadvantage and childhood injury may reduce the burden of ED presentations.

Associations between Apgar scores and children's educational outcomes at eight years of age.

BACKGROUND: Low Apgar scores are associated with neonatal morbidity and mortality, but effects of Apgar scores of 0-5, 6, 7, 8 and 9 (compared with 10) on longer-term neurodevelopmental outcomes are less clear. AIM: To examine the associations between Apgar scores of 0-5, 6, 7, 8 and 9 (compared with 10) and children's educational outcomes as measured by the Australian National Assessment Program-Literacy and Numeracy (NAPLAN) tests at age eight. MATERIALS AND METHODS: We merged perinatal data including all children born in South Australia from 1999 to 2008 with school assessment data (NAPLAN). School assessments included five learning areas (domains)-reading, writing, spelling, grammar and numeracy. Each domain was categorised according to performing at or below National Minimum Standards (≤NMS). Effects were estimated using Augmented Inverse Probability Weighting (AIPW) accounting for a range of maternal, perinatal and sociodemographic characteristics. RESULTS: Risk differences comparing five-minute Apgar scores of 0-5 with Apgar scores of 10 for children performing ≤NMS for each domain were: reading (0.07 (95% CI -0.16 to 0.29)), writing (0.27 (95% CI -0.14 to 0.68)), spelling (0.15 (95% CI -0.10 to 0.40)), grammar (0.04 (95% CI -0.21 to 0.29)) and numeracy (0.21 (95% CI -0.04 to 0.45)). Risk differences for children performing ≤NMS were also evident when Apgar score of 6 was compared with Apgar score of 10. CONCLUSIONS: Children with five-minute Apgar scores of 0-5 and 6, compared with Apgar score of 10, are at higher risk of scoring at/below the NMS on the NAPLAN assessments at eight years.

Preschool attendance and developmental outcomes at age five in Indigenous and non-Indigenous children: a population-based cohort study of 100 357 Australian children.

BACKGROUND: Policies to increase Australian Indigenous children's participation in preschool aim to reduce developmental inequities between Indigenous and non-Indigenous children. This study aims to understand the benefits of preschool participation by quantifying the association between preschool participation in the year before school and developmental outcomes at age five in Indigenous and non-Indigenous children. METHODS: We used data from perinatal, hospital, birth registration and school enrolment records, and the Australian Early Development Census (AEDC), for 7384 Indigenous and 95 104 non-Indigenous children who started school in New South Wales, Australia in 2009/2012. Preschool in the year before school was recorded in the AEDC. The outcome was developmental vulnerability on ≥1 of five AEDC domains, including physical health, emotional maturity, social competence, language/cognitive skills and communication skills/general knowledge. RESULTS: 5051 (71%) Indigenous and 68 998 (74%) non-Indigenous children attended preschool. Among Indigenous children, 33% of preschool attenders and 44% of the home-based care group were vulnerable on ≥1 domains, compared with 17% of preschool attenders and 33% in the home-based care group among non-Indigenous children. In the whole population model, the adjusted risk difference for developmental vulnerability among preschool attenders was -7.9 percentage points (95% CI, -9.8 to -6.1) in non-Indigenous children and -2.8 percentage points (95% CI -4.8 to -0.7) in Indigenous children, compared with Indigenous children in home-based care. CONCLUSIONS: Our findings suggest a likely beneficial effect of preschool participation on developmental outcomes, although the magnitude of the benefit was less among Indigenous compared with non-Indigenous children.

The impact of women's empowerment on their children's early development in 26 African countries.

BACKGROUND: Every year more than 200 million children under-five years fail to achieve their full developmental potential in low- and middle-income countries (LMICs). Although women´s empowerment has been associated with improved child health and development outcomes, this is a topic little studied in LMICs. We investigated the associations between women´s empowerment and early childhood development among a sample population of 84537 children aged 36-59 months from national health surveys of 26 African countries. METHODS: We used data from Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS) ranging from 2010 to 2018. Four developmental domains were assessed among children using the Early Childhood Development Index: literacy-numeracy, physical, learning and socioemotional. Women's empowerment in attitude to violence, social independence and decision-making was evaluated using the SWPER global, a validated survey-based index. We reported effect sizes for each country and a combined estimate of the association. The study covers all countries with surveys in the region and uses a novel approach for measuring women's empowerment, the SWPER. RESULTS: Across all countries, 15.1% of the children were on track in the literacy-numeracy domain, 92.3% in physical, 81.3% in learning and 67.8% in socio-emotional. The odds of a child being on track in literacy-numeracy increased by 34% (odds ratio (OR) = 1.34; 95% confidence interval (CI) = 1.31-1.37), 88% (OR = 1.88; 95% CI = 1.85-1.91) and 34% (OR = 1.34; 95% CI = 1.29-1.39), with a one standard deviation increase in the scores of attitudes to violence, social independence and decision-making domains of empowerment, respectively. No effect of empowerment was observed for the other domains of child development. CONCLUSIONS: Our results show a consistent positive effect of empowerment on the literacy-numeracy domain of child development cross-nationally in Africa and this was particularly evident for the social independence domain of the SWPER. Programs and interventions may also consider addressing the reduction of gender inequalities to improve child development.

Comparison of the Tree-Based Machine Learning Algorithms to Cox Regression in Predicting the Survival of Oral and Pharyngeal Cancers: Analyses Based on SEER Database.

This study aims to demonstrate the use of the tree-based machine learning algorithms to predict the 3- and 5-year disease-specific survival of oral and pharyngeal cancers (OPCs) and compare their performance with the traditional Cox regression. A total of 21,154 individuals diagnosed with OPCs between 2004 and 2009 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. Three tree-based machine learning algorithms (survival tree (ST), random forest (RF) and conditional inference forest (CF)), together with a reference technique (Cox proportional hazard models (Cox)), were used to develop the survival prediction models. To handle the missing values in predictors, we applied the substantive model compatible version of the fully conditional specification imputation approach to the Cox model, whereas we used RF to impute missing data for the ST, RF and CF models. For internal validation, we used 10-fold cross-validation with 50 iterations in the model development datasets. Following this, model performance was evaluated using the C-index, integrated Brier score (IBS) and calibration curves in the test datasets. For predicting the 3-year survival of OPCs with the complete cases, the C-index in the development sets were 0.77 (0.77, 0.77), 0.70 (0.70, 0.70), 0.83 (0.83, 0.84) and 0.83 (0.83, 0.86) for Cox, ST, RF and CF, respectively. Similar results were observed in the 5-year survival prediction models, with C-index for Cox, ST, RF and CF being 0.76 (0.76, 0.76), 0.69 (0.69, 0.70), 0.83 (0.83, 0.83) and 0.85 (0.84, 0.86), respectively, in development datasets. The prediction error curves based on IBS showed a similar pattern for these models. The predictive performance remained unchanged in the analyses with imputed data. Additionally, a free web-based calculator was developed for potential clinical use. In conclusion, compared to Cox regression, ST had a lower and RF and CF had a higher predictive accuracy in predicting the 3- and 5-year OPCs survival using SEER data. The RF and CF algorithms provide non-parametric alternatives to Cox regression to be of clinical use for estimating the survival probability of OPCs patients.

Educational activities on language and behavioural outcomes at school entry are more important for socioeconomically disadvantaged children: a prospective observational study of Australian children.

BACKGROUND: To investigate whether time spent in educational activities at 2-3 years and developmental outcomes at school entry differ among children from different socioeconomic backgrounds. METHODS: Participants were from the Longitudinal Study of Australian Children (n=4253). Time spent in educational activities was collected using 24-hour time-use diaries. Income was measured using parent self-report. Receptive vocabulary was assessed using the Peabody Picture Vocabulary Test, and problem behaviours were measured by the Strengths and Difficulties Questionnaire. Marginal structural models were used to test whether the effects of educational activities on outcomes differed by income. RESULTS: Children exposed to both <30 min/day in educational activities and being in a low-income household were at greater risk of poorer outcomes at school entry than the simple sum of their independent effects. Compared with children who spent ≥30 min/day in educational activities from high-income households, children who experienced <30 min/day in educational activities from low-income households had a 2.30 (95% CI 1.88 to 2.80) higher risk of having a receptive vocabulary score in the lowest quartile at school entry. The Relative Excess Risk due to Interaction of 0.15 (95% CI -0.38 to 0.67) was greater than 0, indicating a super-additive effect measure modification by income. These patterns were similar for behavioural outcomes. CONCLUSIONS: Our findings suggest that if there was an intervention of sufficient dose to increase the amount of time spent in educational activities to at least 30 min/day for children in the lower-income group, the risk of children having sub-optimal receptive vocabulary would be reduced by 45% and the risk of teacher-reported conduct and hyperactivity problems reduced by 67% and 70%, respectively.

Effect of maternal smoking during pregnancy on childhood type 1 diabetes: a whole-of-population study.

AIMS/HYPOTHESIS: Evidence of an association between maternal smoking during pregnancy (prenatal smoking) and childhood type 1 diabetes is mixed. Previous studies have been small and potentially biased due to unmeasured confounding. The objectives of this study were to estimate the association between prenatal smoking and childhood type 1 diabetes, assess residual confounding with a negative control design and an E-value analysis, and summarise published effect estimates from a meta-analysis. METHODS: This whole-of-population study (births from 1999 to 2013, participants aged ≤15 years) used de-identified linked administrative data from the South Australian Early Childhood Data Project. Type 1 diabetes was diagnosed in 557 children (ICD, tenth edition, Australian Modification [ICD-10-AM] codes: E10, E101-E109) during hospitalisation (2001-2014). Families not given financial assistance for school fees was a negative control outcome. Adjusted Cox proportional HRs were calculated. Analyses were conducted on complete-case (n = 264,542, type 1 diabetes = 442) and imputed (n = 286,058, type 1 diabetes = 557) data. A random-effects meta-analysis was used to summarise the effects of prenatal smoking on type 1 diabetes. RESULTS: Compared with non-smokers, children exposed to maternal smoking only in the first or second half of pregnancy had a 6% higher type 1 diabetes incidence (adjusted HR 1.06 [95% CI 0.73, 1.55]). Type 1 diabetes incidence was 24% lower (adjusted HR 0.76 [95% CI 0.58, 0.99]) among children exposed to consistent prenatal smoking, and 16% lower for exposure to any maternal smoking in pregnancy (adjusted HR 0.84 [95% CI 0.67, 1.08]), compared with the unexposed group. Meta-analytic estimates showed 28-29% lower risk of type 1 diabetes among children exposed to prenatal smoking compared with those not exposed. The negative control outcome analysis indicated residual confounding in the prenatal smoking and type 1 diabetes association. E-value analysis indicated that unmeasured confounding associated with prenatal smoking and childhood type 1 diabetes, with a HR of 1.67, could negate the observed effect. CONCLUSIONS/INTERPRETATION: Our best estimate from the study is that maternal smoking in pregnancy was associated with 16% lower childhood type 1 diabetes incidence, and some of this effect was due to residual confounding.

How many words are Australian children hearing in the first year of life?

BACKGROUND: There is evidence that parents from more socioeconomically disadvantaged backgrounds engage in fewer verbal interactions with their child than more advantaged parents. This leads to the so-called, '30 million-word gap'. This study aims to investigate the number of words children hear and the number of vocalizations children produce in their first year of life and examines whether these aspects of the early language home environment differ by maternal education. METHODS: Mothers were recruited into a five-year prospective cohort study and categorized into either high or low maternal education groups. Data was derived from the first two waves of the study, when the children were six and twelve months old. At both waves, children were involved in day-long audio recordings using the Language Environment Analysis software that provided automatic counts of adult words spoken to the child, child vocalizations and conversational turns. Descriptive results are presented by maternal education groups. RESULTS: There was large variation within each maternal education group, with the number of adult words spoken to the child ranging from 2958 to 39,583 at six months and 4389 to 45,849 at twelve months. There were no meaningful differences between adult words, child vocalizations or conversational turns across maternal education groups at either wave of data collection. CONCLUSIONS: These results show that a word gap related to maternal education is not apparent up to twelve months of age. The large variability among both maternal education groups suggests that universal interventions that encourage all parents to talk more to their child may be more appropriate than interventions targeted towards disadvantaged families during the first year of life.

Potentially preventable hospitalisations in children: a comparison of definitions.

OBJECTIVE: To compare admission rate, cumulative incidence and social distribution of potentially preventable hospitalisations (PPHs) among children according to the current Australian adult definition, and the child definition developed in New Zealand. DESIGN, SETTING, PARTICIPANTS: Deidentified, linked public hospital, births registry and perinatal data of children aged 0-10 years born 2002-2012 in South Australia (n=1 91 742). MAIN OUTCOME MEASURES: PPH admission rates among 0-10 year olds and cumulative incidence by age 5 under the adult and child definitions. Cumulative incidence was assessed across indicators of social and health disadvantage. RESULTS: PPH admission rates among 0-10 year olds were 25.6 (95% CI 25.3 to 25.9) and 59.9 (95% CI 59.5 to 60.4) per 1000 person-years for the adult and child definitions, respectively. Greater absolute differences in admission rates between definitions were observed at younger ages (age <1 difference: 75.6 per 1000 person-years; age 10 difference: 1.4 per 1000 person-years). Cumulative incidence of PPHs among 0-5 year olds was higher under the child (25.0%, 95% CI 24.7 to 25.2) than the adult definition (12.8%, 95% CI 12.6 to 13.0). Higher PPH incidence was associated with social and health disadvantage. Approximately 80% of the difference in admission rate between definitions was due to five conditions. CONCLUSIONS: Respiratory conditions and gastroenteritis were key contributors to the higher PPH admission rate and cumulative incidence among children when calculated under the child definition compared to the adult definition. Irrespective of definition, higher PPH cumulative incidence was associated with social and health disadvantage at birth.

The changing temporal association between caesarean birth and neonatal death in Ethiopia: secondary analysis of nationally representative surveys.

OBJECTIVE: To examine the changing temporal association between caesarean birth and neonatal death within the context of Ethiopia from 2000 to 2016. DESIGN: Secondary analysis of Ethiopian Demographic and Health Surveys. SETTING: All administrative regions of Ethiopia with surveys conducted in 2000, 2005, 2011 and 2016. PARTICIPANTS: Women aged 15-49 years with a live birth during the 5 years preceding the survey. MAIN OUTCOME MEASURES: We analysed the association between caesarean birth and neonatal death using log-Poisson regression models for each survey adjusted for potential confounders. We then applied the 'Three Delays Model' to 2016 survey to provide an interpretation of the association between caesarean birth and neonatal death in Ethiopia. RESULTS: The adjusted prevalence ratios (aPR) for neonatal death among neonates born via caesarean section versus vaginal birth increased over time, from 0.95 (95% CI: 0.29 to 3.19) in 2000 to 2.81 (95% CI: 1.11 to 7.13) in 2016. The association between caesarean birth and neonatal death was stronger among rural women (aPR (95% CI) 3.43 (1.22 to 9.67)) and among women from the lowest quintile of household wealth (aPR (95% CI) 7.01 (0.92 to 53.36)) in 2016. Aggregate-level analysis revealed that an increased caesarean section rates were correlated with a decreased proportion of neonatal deaths. CONCLUSIONS: A naïve interpretation of the changing temporal association between caesarean birth and neonatal death from 2000 to 2016 is that caesarean section is increasingly associated with neonatal death. However, the changing temporal association reflects improvements in health service coverage and secular shifts in the characteristics of Ethiopian women undergoing caesarean section after complicated labour or severe foetal compromise.

Process trumps potential public good: better vaccine safety through linked cross-jurisdictional immunisation data in Australia.

OBJECTIVE: To provide insights into complexities of seeking access to state and federal cross-jurisdictional data for linkage with the Australian Childhood Immunisation Register (ACIR). We provide recommendations for improving access and receipt of linked datasets involving Australian Government-administered data. METHODS: We describe requirements for linking eleven federal and state data sources to establish a national linked dataset for safety evaluation of vaccines. The required data linkage methodology for integrating cross-jurisdictional data sources is also described. RESULTS: Extensive negotiation was required with 18 different agencies for 21 separate authorisations and 12 ethics approvals. Three variations of the 'best practice' linkage model were implemented. Australian Government approval requests spanned nearly four years from initial request for data, with a further year before ACIR data transfer to the linkage agency. CONCLUSIONS: Integration of immunisation registers with other data collections is achievable in Australia but infeasible for routine and rapid identification of vaccine safety concerns. Lengthy authorisation requirements, convoluted disparate application processes and inconsistencies in data supplied all contribute to delayed data availability. Implications for public health: Delayed data access for safety surveillance prevents timely epidemiological reviews. Poor responsiveness to safety concerns may erode public confidence, compromising effectiveness of vaccination programs through reduced participation.

Effect decomposition through multiple causally nonordered mediators in the presence of exposure-induced mediator-outcome confounding.

Avin et al (2005) showed that, in the presence of exposure-induced mediator-outcome confounding, decomposing the total causal effect (TCE) using standard conditional exchangeability assumptions is not possible even under a nonparametric structural equation model with all confounders observed. Subsequent research has investigated the assumptions required for such a decomposition to be identifiable and estimable from observed data. One approach was proposed by VanderWeele et al (2014). They decomposed the TCE under three different scenarios: (1) treating the mediator and the exposure-induced confounder as joint mediators; (2) generating path-specific effects albeit without distinguishing between multiple distinct paths through the exposure-induced confounder; and (3) using so-called randomised interventional analogues where sampling values from the distribution of the mediator within the levels of the exposure effectively marginalises over the exposure-induced confounder. In this paper, we extend their approach to the case where there are multiple mediators that do not influence each other directly but which are all influenced by an exposure-induced mediator-outcome confounder. We provide a motivating example and results from a simulation study based on from our work in dental epidemiology featuring the 1982 Pelotas Birth Cohort in Brazil.

Impact of caesarean section on breastfeeding indicators: within-country and meta-analyses of nationally representative data from 33 countries in sub-Saharan Africa.

OBJECTIVE: To examine the impact of caesarean section on breastfeeding indicators-early initiation of breastfeeding, exclusive breastfeeding under 6 months and children ever breastfed (at least once)-in sub-Saharan Africa. DESIGN: Secondary analysis of Demographic and Health Surveys (DHS). SETTING: Thirty-three low-income and middle-income countries with a survey conducted between 2010 and 2017/2018. PARTICIPANTS: Women aged 15-49 years with a singleton live last birth during the 2 years preceding the survey. MAIN OUTCOME MEASURES: We analysed the DHS data to examine the impact of caesarean section on breastfeeding indicators using the modified Poisson regression models for each country adjusted for potential confounders. For each breastfeeding indicator, the within-country adjusted prevalence ratios (aPR) were pooled in random-effects meta-analysis. RESULTS: The within-country analyses showed, compared with vaginal birth, caesarean section was associated with aPR for early initiation of breastfeeding that ranged from 0.24 (95% CI 0.17 to 0.33) in Tanzania to 0.89 (95% CI 0.78 to 1.00) in South Africa. The aPR for exclusive breastfeeding under 6 months ranged from 0.58 (95% CI 0.34 to 0.98) in Angola to 1.93 (95% CI 0.46 to 8.10) in Cote d'Ivoire, while the aPR for children ever breastfed ranged from 0.91 (95% CI 0.82 to 1.02) in Gabon to 1.02 (95% CI 0.99 to 1.04) in Gambia. The meta-analysis showed caesarean section was associated with a 46% lower prevalence of early initiation of breastfeeding (pooled aPR, 0.54 (95% CI 0.48 to 0.60)). However, meta-analysis indicated little association with exclusive breastfeeding under 6 months (pooled aPR, 0.94 (95% CI 0.88 to 1.01)) and children ever breastfed (pooled aPR, 0.98 (95% CI 0.98 to 0.99)) among caesarean versus vaginally born children. CONCLUSIONS: Caesarean section had a negative influence on early initiation of breastfeeding but showed little difference in exclusive breastfeeding under 6 months and children ever breastfed in sub-Saharan Africa.

How much emergency department use by vulnerable populations is potentially preventable?: A period prevalence study of linked public hospital data in South Australia.

OBJECTIVES: To quantify emergency department (ED) presentations by individuals within vulnerable populations compared with other adults and the extent to which these are potentially preventable. DESIGN: Period prevalence study from 2005-2006 to 2010-2011. SETTING: Person-linked, ED administrative records for public hospitals in South Australia. PARTICIPANTS: Adults aged 20 or more in South Australia's metropolitan area presenting to ED and categorised as Refugee and Asylum Seeker Countries of birth (RASC); Aboriginal; those aged 75 years or more; or All others. MAIN OUTCOME MEASURES: Unadjusted rates of ambulatory care sensitive condition (ACSC), general practitioner (GP)-type presentations and associated direct ED costs among mutually exclusive groups of individuals. RESULTS: Disparity between RASC and All others was greatest for GP-type presentations (423.7 and 240.1 persons per 1000 population, respectively) with excess costs of $A106 573 (95% CI $A98 775 to $A114 371) per 1000 population. Aboriginal had highest acute ACSC presenter rates (125.8 against 51.6 per 1000 population) with twice the risk of multiple presentations and $A108 701 (95% CI $A374 to $A123 029) per 1000 excess costs. Those aged 75 or more had highest chronic ACSC presenter rates (119.7vs21.1 per 1000), threefold risk of further presentations (incidence rate ratio 3.20, 95% CI 3.14 to 3.26) and excess cost of $A385 (95% CI $A178 160 to $A184 609) per 1000 population. CONCLUSIONS: Vulnerable groups had excess ED presentations for a range of issues potentially better addressed through primary and community healthcare. The observed differences suggest inequities in the uptake of effective primary and community care and represent a source of excess cost to the public hospital system.