External Publications Using GUI Data

This retrospective cross-sectional paper examines the relationship between early breastfeeding exposure and children’s academic test scores at nine years of age independent of a wide range of possible confounders. The final sample comprised 8226 nine-year-old school children participating in the first wave of the Growing Up in Ireland study. The children were selected through the Irish national school system using a 2-stage sampling method and were representative of the nine-year population. Information relating to breastfeeding initiation and exposure duration was obtained retrospectively at nine years of age via parental recall and children’s academic performance was assessed using standardised reading and mathematics tests. Hierarchical linear regression analysis with robust standard errors to control for clustering at the school level was used to quantify the effect of breastfeeding on children’s test scores. Propensity score matching was used to compare treatment effects across groups defined by their propensity to breastfeed. In unadjusted analysis, children who were breastfed scored 8.67 percentage points higher on reading and 7.42 percentage points higher on mathematics compared to those who were never breastfed. While the breastfeeding advantage attenuated appreciably when adjusted for a range of child, maternal, socio-economic and socio-environmental characteristics, children who were breastfed continued to enjoy a significant test score advantage of 3.24 (p < 0.001) and 2.23 (p < 0.001) percentage points on reading and mathematics respectively compared to those who were never breastfed. Any amount of breastfeeding was associated with significantly higher test scores than no exposure, but evidence of a dose-response relationship was weak. The results of the propensity score matching analysis indicated that the test score advantage of breastfed children is robust and that the magnitude of the effect varies across groups defined by their propensity to breastfeed, being largest amongst the most socially disadvantaged and falling to near zero among the most advantaged group.

Whether breastfeeding is protective against the development of childhood overweight and obesity remains the subject of considerable debate. Although a number of meta-analyses and syntheses of the literature have concluded that the greater preponderance of evidence indicates that breastfeeding reduces the risk of obesity, these findings are by no means conclusive. The present study used data from the Growing Up in Ireland study to examine the relationship between retrospectively recalled breastfeeding data and contemporaneously measured weight status for 7798 children at nine-years of age controlling for a wide range of variables including; socio-demographic factors, the child’s own lifestyle-related behaviours, and parental BMI. The results of the multivariable analysis indicated that being breastfed for between 13 and 25 weeks was associated with a 38 percent (p < 0.05) reduction in the risk of obesity at nine-years of age, while being breastfed for 26 weeks or more was associated with a 51 percent (p < 0.01) reduction in the risk of obesity at nine-years of age. Moreover, results pointed towards a dose–response patterning in the data for those breastfed in excess of 4 weeks. Possible mechanisms conveying this health benefit include slower patterns of growth among breastfed children, which it is believed, are largely attributable to differences in the composition of human breast milk compared with synthesised formula. The suggestion that the choice of infant feeding method has important implications for health and development is tantalising as it identifies a modifiable health behaviour that is amenable to intervention in primary health care settings and has the potential to improve the health of the population.

The incidence of adiposity in the early years of life has outgrown the prevalence in older children and adolescents globally; however, the factors influencing weight gain are predominantly studied in adults. This study examines the relationship between changing economic conditions during the Irish recession and child weight in a nationally representative sample of 10,011 Irish children studied at 9 months, 3 years and 5 years old. This study is the first to use longitudinal anthropometric measurements to estimate the impact of direct parental unemployment on children’s weight. Fixed effect logistic regression is used to examine the effects of parental unemployment on weight using the Growing up in Ireland infant cohort from 2008 to 2013. Weight and length/height measured by trained interviewers and child growth charts are used to quantify children’s weight status according to BMI-for-age and weight-for-age measures. For BMI-for-age, the probability of a child being classified as overweight/obese is 8 percentage points higher if either parent experiences unemployment. A sensitivity analysis of weight-for-age indicates that the probability is of similar magnitude across several alternative growth charts and definitions of adiposity (the WHO standard, British Growth Reference, and Centers for Disease Control). The analysis is repeated, cross-sectionally, for physical activity and diet to clarify mechanisms of effect. The probability of a child consuming healthy food and physical activity with an implied cost is lower if either parent becomes unemployed. A focus on overweight/obesity in the early years is of crucial importance as if current trends are not addressed, a generation of children may grow up with a higher level of chronic disease.

It is well-established that participation in shared book reading interactions with caregivers supports children’s early language and literacy development. Most of this literature focuses on reading experiences during the preschool period. Less is known about the nature and importance of such practices during infancy. Therefore, the goal of this study was to examine literacy practices between parents and infants in a large cohort study, Growing Up in Ireland. Interview, survey, and direct measurements of children’s language skills were used to examine whether parent-report of book reading practices when children were 9-months predicted child expressive vocabulary at 36-months (N = 9171). Regression analysis indicated that approximately 80% of 9-month-old Irish children are read to by parents. Characteristics of families who were more likely to report reading with children emerged: those with higher educational attainment, fewer depressive symptoms, and those who report a high-quality home language environment (e.g., reported talking more to children during everyday activities). Furthermore, children who were read to at 9-months had stronger expressive vocabulary skills at 36-months, even after accounting for socio-demographic and home literacy environment covariates measured at both 9- and 36-months. Results are discussed using a bioecological framework to describe how proximal and distal factors in the child’s environment converge to impact early childhood literacy development.

Epidemiological evidence suggests that poor physical health and depression are highly co-morbid. To date, however, no study has considered whether depression in parents caring for children with developmental disabilities is partly driven by poor physical health. Using data from the Growing Up in Ireland national cohort study (2006 to date), 627 parents of children with developmental disabilities were compared with 7941 parents of typically developing children on scores from the Centre for Epidemiological Depression Scale, chronic health conditions, socio-demographic and child behavioural characteristics. Having a child with disabilities was associated with a higher risk of depression (odds ratio (OR) = 1.83, 95% confidence interval (CI): 1.43, 2.35) compared to parents of typically developing children. Adjusting for the presence of chronic health conditions accounted for some of this excess risk (OR = 1.77, 95% CI: 1.38, 2.27). The association between having a child with disabilities and increased risk of depression was explained, however, by adjusting for the child problem behaviours (OR = 1.07, 95% CI: 0.81, 1.43). This study has confirmed, in a population-based sample, the high risk of depression in parents caring for children with developmental disabilities after adjusting for the presence of a chronic health condition. Importantly, given that poor mental health in these parents is associated with a battery of negative health and social family outcomes, it is imperative that health professionals pay attention to the mental health needs of these parents.

Epidemiological evidence suggests that obesity and depression are highly co-morbid. In a national cohort study, we examined whether parents caring for children with disabilities were more likely to be classified as obese compared to parents of children without disabilities and if obesity was associated with depressive symptoms or child behaviour characteristics. Using data from the Growing Up in Ireland National Longitudinal Study of Children (2006 to date), 627 parents of children with developmental disabilities were compared with 7941 parents of typically developing children on objectively measured levels of obesity (body mass index ≥30 kg/m2), depression, health behaviours, chronic health conditions, socio-demographic and child behavioural characteristics. Parents of children with disabilities were more likely to be classified as obese compared to control parents (24.5% vs. 19.6%, p = 0.005, Cramer’s V < 0.1). Depression was not associated with obesity. However, the odds of obesity increased with increasing child problem behaviour (OR 1.05, 95% CI 1.03–1.06). Over half (57%) of obese parents caring for children with disabilities reported trying to lose weight often or very often. This study has confirmed, in a population-based sample, the high risk of obesity in parents caring for children with disabilities after adjusting for the presence of depression and other health behaviours; increasing child problem behaviours were predictive of obesity. Importantly, given the negative health correlates of obesity, it is imperative that health professionals pay attention to weight issues in these parents and support their efforts in managing these issues.

The objective was to identify determinants of uptake and maintenance of active school travel (AST) over 4 years in children aged 9 at baseline. Data from wave 1 (n=8502) and 2 (n=7479) of the Growing Up in Ireland study were analysed. At 9- and 13-years 25% and 20% engaged in AST. Children were more likely to maintain or take-up AST if they lived in an urban area. Change in distance to school influenced both maintenance and adoption of AST, with a negative impact seen for increased distance between 9 and 13 years and a positive impact seen for decreased distance. Some factors which predict uptake and maintenance of AST are modifiable and can inform intervention development.

Children, particularly those of preschool ages (below 3 years), spend the majority of time indoors in the family home. Home conditions can impact upon occupant’s health, with energy poverty identified as a public health concern in Europe and internationally. Children growing up in energy poor homes may be especially vulnerable to health impacts, though the area is relatively understudied. This study addresses a gap in understanding, examining the effect of household energy poverty on the health of resident children using longitudinal data from two cohorts – an Infant Cohort (aged 9 months to 5 years) and a Child Cohort (aged 9 years to 17–18 years), growing up in Ireland.

Panel logistic regression models adjust for a range of covariates including socioeconomic and household information as well as smoking in the household. For the Infant Cohort, household energy poverty was associated with a 1.41 times higher odds of child respiratory illness (p = 0.003; 95% Confidence Interval (CI) 1.12–1.77), and 1.47 times the odds of child wheezing (p < 0.001; 95% CI 1.25–1.74). The odds of a young child being rated as very healthy was lower (point estimate: 0.85, p = 0.011; 95% CI 0.75–0.96). For older children, the relationships were not statistically significant. The risk that energy poverty presents for the health of young children merits continued policy attention.

Objectives
Maternal health behaviours (MHBs) can influence pregnancy outcomes. Despite efforts internationally to encourage positive MHBs, women often fail to comply with pregnancy guidelines. International studies show differences in MHBs between nationalities and an effect of time spent in the host country. There is limited Irish data in this area, with no previous research relating to the effect of time in Ireland.

Study design
This study is a cross-sectional analysis of the Growing Up in Ireland infant cohort, a nationally representative longitudinal study.

Methods
Examination of the MHBs of non-Irish nationals during pregnancy and the effect of time in Ireland on the said behaviours.

Results
An association was found between time spent in Ireland and increased alcohol consumption prevalence. Those living in Ireland for ≤5 years were 60.8% less likely to consume alcohol during pregnancy (0.000) and 29.3% less likely to take folic acid before conception (0.021). Those who smoked during pregnancy were 98.6% more likely to consume alcohol (0.000) and those who consumed alcohol were 95.2% more likely to smoke during pregnancy (0.000).

Conclusions
The results demonstrate differences in MHBs and the influence of time living in Ireland. These findings are of relevance for policy and intervention planning to optimise pregnancy outcomes among non-nationals.

Children born preterm have poorer outcomes than children born full-term, but the caregiving environment can ameliorate some of these differences. Recent research has proposed that preterm birth may be a plasticity factor, leading to better outcomes for preterm than full-term infants in higher quality environments. This analysis uses data from two waves of an Irish study of children (at 9 months and 3 years of age, n = 11,134 children) and their caregivers (n = 11,132 mothers, n = 9998 fathers) to investigate differences in how caregiving affects social, cognitive, and motor skills between full-term, late preterm, and very preterm children. Results indicate that parental emotional distress and quality of attachment are important for child outcomes. Both being born very preterm and late preterm continue to be risk factors for poorer outcomes at 3 years of age. Only fathers’ emotional distress significantly moderated the effect of prematurity on infants’ cognitive and social outcomes—no other interactions between prematurity and environment were significant. These interactions were somewhat in line with diathesis stress, but the effect sizes were too small to provide strong support for this model. There is no evidence that preterm birth is a plasticity factor.

Background
Self-harm is a major public health concern in young people and is governed by a complex interaction of different risk factors. While many studies have identified these risk factors, less is known about how they tend to co-occur together.

Methods
A latent class analysis was conducted using risk factors for self-harm from two waves at ages 13 and 17 from the Growing Up in Ireland (GUI) study their associations with self-harm were examined longitudinally at ages 17 and 20, respectively.

Results
At age 13, there was a ‘peer problems’ group with higher probabilities of bullying, being unpopular and internalising problems and a ‘school and substance use problems’ group with higher probabilities of substance use, truancy or excessive absence from school and violence. Both of these two groups had over a two-fold risk of self-harm at age 17 in comparison to the low risk factor group. At age 17, there was a group with depression that was diagnosed by a medical professional with the highest relative risk (RR:13.9 (95 % CI 10.2–19.0)) of self-harm at age 20. Two other groups with undiagnosed depression had high probabilities of being bullied, and either high or low probabilities of substance use that had a 9.4 (95 % CI 6.8–13.1) and 7.4 (95 % CI 5.5–10.0) relative risk of self-harm at age 20, respectively.

Conclusions
Identifying hidden sub-groups using risk factors for self-harm in young people can inform potential public health interventions by clinicians and other professionals who work with young people.

Although children’s relationships with their parents and teachers contribute to their school adjustment and achievement, few studies have examined interactions between these relationships, particularly for father-child relationships. Using the Growing Up in Ireland birth cohort (N = 7507, 50.3% male), we examined child-adult relationship quality – rated by parents at age 3 and by teachers at age 5 – as predictors of teacher-rated behavioural adjustment and academic achievement at age 9 (indexed by self-reported academic self-concepts and performance on formal reading assessments). Controlling for prior levels of problem behaviours, verbal ability, and family SES, our results indicated that children’s relationships with parents and teachers showed small and comparable independent effects on school adjustment and achievement. For mothers and teachers, moderation analyses showed a cumulative risk pattern for conflictual relationships and a compensatory pattern for close relationships. Children are likely to benefit from improving closeness and reducing conflict in adult-child relationships as well as interventions that involve mothers, fathers, and teachers.

Background
There is limited knowledge of the extent of or factors underlying inequalities in uptake of childhood vaccination in Ireland. This paper aims to measure and decompose socioeconomic inequalities in childhood vaccination in the Republic of Ireland.

Methods
The analysis was performed using data from the first wave of the Growing Up in Ireland survey, a nationally representative survey of the carers of over 11,000 nine-month old babies collected in 2008 and 2009. Multivariate analysis was conducted to explore the child and parental factors, including socioeconomic factors that were associated with non-vaccination of children. A concentration index was calculated to measure inequality in childhood vaccination. Subsequent decomposition analysis identified key factors underpinning observed inequalities.

Results
Overall the results confirm a strong socioeconomic gradient in childhood vaccination in the Republic of Ireland. Concentration indices of vaccination (CI = −0.19) show a substantial pro-rich gradient. Results from the decomposition analysis suggest that a substantial proportion of the inequality is explained by household level variables such as socioeconomic status, household structure, income and entitlement to publicly funded care (29.9%, 24% 30.6% and 12.9% respectively). Substantial differences are also observed between children of Irish mothers and immigrant mothers from developing countries.

Conclusions
Vaccination was less likely in lower than in higher income households. Access to publicly funded services was an important factor in explaining inequalities.

Background
Research has demonstrated positive associations between adverse childhood experiences (ACEs) and substance use behaviours in young adults. However, many of these are based on cross-sectional data. The pathway between ACEs and substance misuse among emerging adults is also not fully understood and few studies have investigated potential mediating factors.

Methods
We analysed data from the Child Cohort of the Growing Up in Ireland study, a nationally representative longitudinal sample of children recruited at 9 years of age (n = 4,729). Logistic regression was used to examine individual and cumulative ACE exposure relationships with substance use at age 20 years. Mediation analyses were used to assess whether parental and peer relationships and school engagement mediate ACE history associations with substance use behaviours.

Results
ACE exposure relationships with current cannabis use, other illicit drug use and problematic drug use were observed. In particular, young adults who had experienced 2 ACEs or 3 + ACEs had an approximate two-fold (OR=1.80, 95 % CI: 1.29, 2.51) and approximate three-fold (OR=2.94, 95 % CI: 2.06, 4.19) increased odds of problematic drug use, respectively, when compared to participants who had experienced no ACEs during the study period. Mediation analyses suggested that parent and peer attachment and liking school partially mediate relationships between ACEs and substance use behaviours.

Conclusions
Children who have experienced ACEs are at higher risk of future substance use and problematic drug use. In supporting these children, identified mediators such as interpersonal relationships and school engagement may help guide selection of prevention interventions.

Objectives
To assess the impact of digital media usage on psychiatric symptoms in an adolescent population utilizing a longitudinal cohort design.

Methods
Using two waves of the GUI child cohort, age 13 (N = 7527) and age 17/18 (N = 6126), we used latent class analysis (LCA) to create latent groups centred around self-reported time spent online, and the self-reported behaviours children engaged with online. At both waves, the 4 class latent model suited best. We used the different symptoms scales of the Strengths and Difficulties Questionnaires (SDQ), self-reported, at age 17 as our outcome variable. Using linear regression analysis, we then examined the associations between our latent class model and psychiatric symptoms, using moderate usage as our reference group, with adjustments being made for baseline psychiatric symptoms, maternal education and pre-diagnosed mental disorder.

Results
For females, placement in the high usage group at 13 was associated with increased internalizing symptoms, whereas placement in the high usage group at 17 was associated with an increase in all symptoms. For males, placement in the high usage group at 17 was associated with increased emotional symptoms, and placement in the “low usage & behaviour engagement”group, a group showing low reported time online and low engagement in our measured online behaviours at 17, was associated with an increase in all symptoms. Finally for both sexes, placement in the “moderate usage, entertainment only” group at age 13, (a group reporting no school-based online engagement), was associated with increases in all symptoms except emotional symptoms.

Conclusion
High digital media usage is associated with increased psychiatric symptoms in both males and females, with moderate usage associated with positive effects on symptoms compared to both our high usage, and low usage groups.

Keywords
Digital engagement, Psychiatric symptoms, Internet usage, Latent class analysis

Multiple factors including the child’s non-linguistic characteristics and caregiving environment can affect language development. Since preterm birth (<37 weeks’ gestation) can negatively affect language development, this study used path analysis to investigate whether the influence of preterm birth on expressive language development at 3 and 5 years of age is mediated by a child’s non-linguistic characteristics (temperament and cognitive, motor, and social-personal abilities), caregiving environment (maternal and paternal stress and depression, mother-child and father-child relationship quality), and interactions between these domains. These analyses were conducted using three waves of data (ages: 9 months, 3 years, 5 years) on 8,712 children (4,300 female; 535 preterm) from a nationally-representative longitudinal study in Ireland. Preterm birth was indirectly (but not directly) associated with expressive language at 3 years of age via cognitive and social-personal abilities (but not motor abilities, mother-child relationship quality, or father-child relationship quality) at 9 months. There was no direct or indirect effect of preterm birth on expressive language at 5 years of age. Preterm birth negatively affected mother-child and father-child relationship quality at 3 years via fussy-difficult temperament and mother’s/father’s stress (but not depression) at 9 months. These findings are discussed with reference to international standards for neonatal care, including the need for long-term developmental monitoring of children born preterm by multidisciplinary healthcare teams, alongside parental supports promoting mental health and confidence in caregiving tasks. Future study recommendations are made to expand the tested models in line with family systems perspectives.

This study examined the role of neighbourhood characteristics in explaining socioeconomic inequalities in child mental health (the total difficulties score from the Strengths and Difficulties Questionnaire) using data from Cohort ’08 of Growing Up in Ireland Waves 3 (age 5; baseline) and 5 (age 9; follow-up). Twenty neighbourhood items were grouped into neighbourhood safety, built environments, cohesion, interaction, and disorder. Data were analysed using regression, single and multiple mediation, and network psychometric analyses. We found that neighbourhood safety, cohesion, interaction, and disorder were associated with child mental health. These four domains separately (by up to 18 %) or in concert (by up to 23 %) partially explained socioeconomic inequalities in child mental health. Built environments may explain socioeconomic inequalities in mental health in urban children only. Findings from network analysis indicated that specific concerns over “people being drunk or taking drugs in public” and “this is a safe neighbourhood” had the strongest connections with child mental health. Improving neighbourhood characteristics may be important to reduce socioeconomic inequalities in child mental health in Ireland.

The objective of this paper is to quantify and decompose the socioeconomic gradient in childhood obesity in the Republic of Ireland. The analysis is performed using data from the first wave of the Growing Up in Ireland survey, a nationally representative survey of 8568 nine-year-old children conducted in 2007 and 2008. We estimate concentration indices to quantify the extent of the socioeconomic gradient in childhood obesity and undertake a subsequent decomposition analysis to pinpoint the key factors underpinning the observed inequalities. Overall the results confirm a strong socioeconomic gradient in childhood obesity in the Republic of Ireland. Concentration indices of obesity (CI = −0.168) and overweight/obese (CI = −0.057) show that the gradient is more pronounced in obese children, while results from the decomposition analysis suggest that the majority of the inequality in childhood obesity is explained by parental level variables. Our findings suggest that addressing childhood obesity inequalities requires coordinated policy responses at both the child and parental level.

This paper examines mobility and changes in Body Mass Index (BMI) for a sample of Irish children/adolescents across three waves of the longitudinal Growing Up in Ireland dataset. Particular attention is paid to transitions across the key BMI thresholds of overweight and obesity. Analysis is carried out by gender and by maternal education. In general, mobility is observed, with intra-generational rank-rank BMI coefficients of around 0.63 compared to coefficients of around 0.77 for the mothers of the children over the same time period. Across the distribution as a whole there is relatively little variation by gender and maternal education. However there a gender difference in terms of mobility out of obesity with the Shorrocks mobility index across categories of normal weight/overweight/obesity taking a value of 0.56 for females as opposed to 0.71 for males. This relative lack of mobility is more observed in later rather than earlier adolescence.