External Publications Using GUI Data

Background
Historically, breastfeeding rates in Ireland have been low compared with international averages. It has been suggested that maternal ethnicity and citizenship may influence breastfeeding rates, with ethnic minorities thought more likely to breast feed.

Aim
The aim of this study is to investigate the association among maternal citizenship, ethnicity, birthplace and breast feeding. It is hypothesised that Irish mothers (identified through Irish citizenship, self-identified Irish ethnicity or Irish birthplace) are less likely to breast feed than non-Irish mothers.

Methods
The study population of Growing Up in Ireland: the National Longitudinal Study of Children was used for this study. Analysis was restricted to 11 092 biological mother and infant pairs with a complete breastfeeding history. Logistic regression analysis was used to estimate ORs and 95% CIs for breast feeding relative to maternal citizenship and ethnicity, controlling for the confounding effects of other maternal variables.

Results
Results indicated that 55.9% (6202 of 11 092) of mothers had initiated breast feeding, with only 7.9% (874 of 11 092) of mothers currently breast feeding their infant (at 9 months of age). Irish citizens (4693 of 9368, 50.0%) were significantly less likely to have initiated breast feeding compared with non-Irish citizens (1503 of 1695, 88.7%). Irish born mothers (4179 of 8627, 48.8%) were also significantly less likely to have initiated breast feeding than mothers born elsewhere (2023 of 2462, 82.2%).

Conclusions
Maternal citizenship and ethnicity appear to be the strongest influencing factors on breastfeeding initiation and duration. However, this raises a possibility that the increase in breastfeeding rates seen recently may be the result of increased immigration into Ireland, rather than the success of policy and research efforts.

Background
Globally, childhood obesity is a significant public health problem associated with adverse health and economic consequences. To tackle the problem, we need a comprehensive understanding on how the environment in which we live may influence obesity related behaviours and weight status. Thus, we explore if distance to and number of food outlets ([1] supermarkets and [2] convenience stores) in the local area impact on either dietary quality or body mass index (BMI) in 9-year-old children whilst controlling for socio-economic characteristics of the family.

Methods
Cross sectional analysis of the Growing Up in Ireland (GUI) Study, a two-stage clustered sample of 8568 nine year old children from the Republic of Ireland. Children were recruited from schools (response rate 82%) and age eligible children (response rate 57%) were invited to participate. Height and weight measurements were used to calculate BMI. Diet was assessed using a short food frequency questionnaire and a dietary quality score was generated based on Irish healthy eating guidelines. Socio-economic status was measured using parent reported household class, household net equivalised income and highest level of maternal education. Food access was measured as network distance to (in quintiles) and number of (within 1000km) convenience stores and supermarkets to each participant’s household within the local area. Separate fixed effects regression models were used to assess the impact of local area food access on (1) dietary quality and (2) BMI, stratified by gender.

Results
After controlling for socio-economic characteristics of the household, distance to the nearest supermarket was not associated with dietary quality in boys (Q5 v Q1; B = 0.84, 95% CI, –0.49 to 2.18) or girls (Q5 v Q1; B = –0.41, 95% CI, –1.60 to 0.77). Distance to the nearest convenience store was associated with dietary quality in boys (Q5 v Q1; B = 1.01, 95% CI, 0.13 to 1.89) but not in girls (Q5 v Q1; B = 0.04, 95% CI, –0.71 to 0.80). The number of convenience stores or supermarkets within 1000m of the household did not impact on dietary quality. Access to food outlets was not associated with BMI in girls or boys.

Conclusion
There was little evidence to suggest that access to food stores impact dietary quality or BMI in children. From a population health perspective, strategies tackling environmental factors associated with making poor lifestyle choices are needed. Thus, further research on the association between food access and obesity risk is needed.

Background
Poverty is associated with poor outcomes, yet exposure to distinct poverty trajectories in early childhood is not well understood.

Objective
To understand the prevalence of different trajectories of household poverty and their association with mid-childhood and mother indicators of physical health and psychopathology in Ireland.

Methods
We used a nationally representative, prospective cohort (Growing Up in Ireland–Infant Cohort). Household poverty included lowest third income decile, subjective poverty and material deprivation when children were aged 9 months, and 3, 5, 9 years. We used group-based multitrajectory cluster modelling to classify trajectories of poverty. Using multivariable logistic regression, adjusted with separate child and mother confounders, we assessed the association of poverty trajectories from 9 months to 9 years with child outcomes (overweight, any longstanding illness and psychopathology) at age 9 years and the same poverty trajectories over the same 9-year period with mother outcomes (overweight, any longstanding illness and depression).

Results
Of 11 134 participants, 4 trajectories were identified: never in poverty (43.1%), material/subjective>monetary poverty (16.1%), monetary>material poverty (25.6%) and persistent poverty (15.2%). Children in persistent poverty compared with those in never in poverty experienced higher odds of being overweight at 9 years (adjusted OR (aOR) 1.70, 95% CI 1.34, 2.16), having a longstanding illness (aOR 1.51, 95% CI 1.20, 1.91), and psychopathology (aOR 2.06, 95% CI 1.42, 2.99). The outcomes for primary parents (99.7% were mothers) were as follows: having higher odds of being overweight (aOR 1.49, 95% CI 1.16, 1.92), having a longstanding illness (aOR 2.13, 95% CI 1.63, 2.79), and depression (aOR 3.54, 95% CI 2.54, 4.94).

Conclusions
Any poverty trajectory was associated with poorer psychopathology and physical well-being in late childhood for children and their mothers in Ireland.

Background
Independent associations between screen time (ST)/physical activity (PA) and overweight (OW)/obesity have been demonstrated but little research exists on the role of ST among sufficiently active children.

Purpose
To examine the combined influence of ST and PA on risk of OW/obesity in a nationally representative sample of 9-year-old Irish children.

Methods
The sample in this cross sectional analysis contained 8568 children. Self-report parent data were used to group children into ST and PA categories and related to OW/obesity using forced entry logistic regression.

Results
High ST (> 3 hours/day), bedroom TV and mobile phone ownership increased risk of OW/obesity in high and low active children (P < .05). Low PA (<9 bouts fortnightly) was also associated with OW/obesity. In combined analyses, OW/obesity was lowest in the reference low ST/high PA group with ORs of 1.38, 1.63, and 2.07, respectively, in the low ST/low PA, high ST/high PA, and high ST/low PA groups. Access to electronic media, low socioeconomic status, parental obesity, and not engaging in sports were all related to high ST (P < .05).

Conclusion
This study supports findings that ST is associated with OW/Obesity demonstrating this separately in high and low active children.

Background
The aim of this study was to use a social-ecological approach to examine the influence of individual, social, and environmental factors on moderate-to-vigorous physical activity (MVPA) and screen-time in a sample of 9-year-old children in Ireland.

Methods
The sample was 1509 boys and girls from the Growing Up in Ireland (GUI) national study. MVPA, screen time, and individual, social, and environmental variables were assessed via questionnaires completed by children, their parents, and their teachers. Multiple regression was used to identify factors that correlated with children’s MVPA and screen-time levels.

Results
For boys, factors such as activity with friends (P < .0001) and popularity (P < .01) were associated with MVPA, while factors such as BMI (P < .01) and MVPA (P < .01) were associated with screen time. Similarly for girls, factors such as activity with friends (P < .0001) and sociability were associated with MVPA, however factors such as BMI (P < .05), and access to play space (P < .05) were more closely associated with screen time.

Conclusion
Social factors were more closely associated with MVPA, while individual factors were significantly correlated with screen time for both boys and girls. Correlates differed for boys and girls, suggesting that interventions should consider both the target population as well as the activity behavior.

For the first time, data on children and adolescents with disabilities in Ireland are reported based on the Active Healthy Kids Global Alliance Para Report Card methodology. The most recent data from the last 10 years were used in the grading process (A+ to F), and indicators with insufficient data were graded as incomplete. Of the 10 indicators from the Global Matrix Para Report Cards, grades were assigned to Overall Physical Activity (F), Organized Sport (D), Active Transport (D−), Sedentary Behaviors (D−), Family & Peers (C), School (C−), Community & Environment (B−), and Government (B). Irish disability sport organizations were invited to assess the research-led audit and provided commentary around the final grading. The contextual discussion of the grades is presented through the lens of strengths, weaknesses, opportunities, and threats with the purpose being to provide direction for the reduction of physical activity disparities among children with disabilities.

Background
Parental obesity is a predominant risk factor for childhood obesity. Family factors including socio-economic status (SES) play a role in determining parent weight. It is essential to unpick how shared family factors impact on child weight. This study aims to investigate the association between measured parent weight status, familial socio-economic factors and the risk of childhood obesity at age 9.

Methodology/Principal Findings
Cross sectional analysis of the first wave (2008) of the Growing Up in Ireland (GUI) study. GUI is a nationally representative study of 9-year-old children (N = 8,568). Schools were selected from the national total (response rate 82%) and age eligible children (response rate 57%) were invited to participate. Children and their parents had height and weight measurements taken using standard methods. Data were reweighted to account for the sampling design. Childhood overweight and obesity prevalence were calculated using International Obesity Taskforce definitions. Multinomial logistic regression examined the association between parent weight status, indicators of SES and child weight. Overall, 25% of children were either overweight (19.3%) or obese (6.6%). Parental obesity was a significant predictor of child obesity. Of children with normal weight parents, 14.4% were overweight or obese whereas 46.2% of children with obese parents were overweight or obese. Maternal education and household class were more consistently associated with a child being in a higher body mass index category than household income. Adjusted regression indicated that female gender, one parent family type, lower maternal education, lower household class and a heavier parent weight status significantly increased the odds of childhood obesity.

Conclusions/Significance
Parental weight appears to be the most influential factor driving the childhood obesity epidemic in Ireland and is an independent predictor of child obesity across SES groups. Due to the high prevalence of obesity in parents and children, population based interventions are required.

Background
Population-based studies provide important data to inform policy and service planning for vulnerable children in society. The aim of this study was to characterise social and educational circumstances and self-concept among a nationally representative sample of 13 year olds with developmental disabilities in Ireland.

Methods
A cross-sectional, secondary analysis of data collected from the Growing Up in Ireland (GUI) study was conducted. Descriptive statistics were used to calculate the reported prevalence of disabilities as reported by parents. Differences across the groups (those with and without disabilities) were analysed in relation to gender, socio-economic and school factors. Special education support received in school was described. The association between low self-concept scores (as measured by the Piers Harris Self-Concept Scales 2) and disability type was examined by use of multi-level logistic regression.

Results
Seventeen percent (17.36%) of the sample was reported to have a diagnosis of one or more developmental disabilities. Those with a disability were more likely to live in poorer households, have poorer health status, to experience more episodes of bullying at school, and to have more negative views of school (p<0.05) than their typically-developing peers.

Forty nine percent of children with developmental disabilities were not receiving support in school as reported by parents. Discrepancies in the nature of support received were identified across disability types. Adjusting for individual and school level factors, a disability diagnosis was associated with increased odds of low self-concept scores on three of five self-concept domains. Further associations were identified which differed across disability type.

Conclusions
The findings show that 13 year olds with a disability in Ireland have complex social and educational needs. Findings also suggest significant levels of unmet educational need across this age group. Apparent inequities in access to support in school require further investigation. Reliable measures to provide robust prevalence figures about childhood disabilities in Ireland are needed.

Background
The Covid pandemic arrived in Ireland on February 29, 2020. In the following weeks various restrictions were introduced to stem the spread of the disease. Anxiety over the spread of the disease and over the restrictions introduced had an adverse effect upon mental health. This study examines the change in mental health for two groups: young adults aged around 23 at the time of onset of Covid (the 1998 cohort) and a sample of principal carers (PCs) of children who were aged 13 at the onset of Covid (the 2008 cohort).

Methods
Data were obtained from the two cohorts of the longitudinal Growing Up In Ireland (GUI) survey. The sample included 1953 young adults (from the 1998 cohort) and 3547 principal carers (from the 2008 cohort). Mental health as measured by the Centre for Epidemiological Studies Depression—8 scale was obtained for the last pre-Covid wave and for the Covid wave (surveyed in December 2020). Observations for which CES-D8 was not available in either pre or post Covid waves were excluded. Post-Covid sampling weights were applied. The change in depression rates was decomposed into a growth and distribution effect using a Shapley decomposition. The socioeconomic gradient of CES-D8 was examined pre and post Covid using concentration indices and a transition matrix was constructed to examine the dynamics of changes in CES-D8 and depression pre and post-Covid.

Results
Relative to the last pre-Covid survey, mental health, as measured by CES-D8 deteriorated for both the young adults of the 1998 cohort and the PCs of the 2008 cohort. For young adults, the deterioration was more pronounced for females. There was no observable socioeconomic gradient for poor mental health amongst young adults, both pre and post Covid. For mothers from the 2008 cohort, a gradient was observed during the pre-COVID-19 pandemic period with poorer mental health status for lower-income and less educated mothers. This gradient was less pronounced post-Covid, the levelling-off arising from a greater deterioration in mental health for higher-income and better-educated PCs.

Conclusion
Both observed cohorts showed a significant deterioration in mental health post Covid. For young adults the effect was significantly more pronounced among females and this is consistent with generally poorer mental health amongst females in this age group. There was little or no socioeconomic gradient observed for young adults, but the gradient became more shallow for principal carers. Care must be taken in terms of drawing policy implications from this study as the Covid-19 pandemic was arguably a unique event, even allowing for the likelihood of future pandemics. However, the study highlights the vulnerability of young adults, especially females, to the mental health effects arising from major public health shocks.

This article uses two longitudinal cohort studies (Growing Up in Ireland and the National Educational Panel Study) to examine how shadow education relates to academic performance in Ireland and Germany. Patterns of take-up of, and outcomes from, shadow education are found to reflect the particular country context—aimed at maintaining performance to avoid grade retention in Germany and preparing for a high-stakes upper secondary exam in Ireland. Participation enhances academic performance but only for students with lower levels of prior achievement. However, the relationship is not much stronger than with engagement in structured out-of-school activities. Thus, shadow education appears to be one of a number of strategies used by more privileged families to secure educational advantage.

To date, studies using cross-sectional methodologies make up a majority of the literature surrounding children with autism spectrum disorders and participation in physical activity and screen time. Longitudinal studies are needed to examine how physical activity and screen time behaviors co-develop for children with and without an autism spectrum disorder. To address this research gap, this study compared how physical activity and screen time levels changed over time (9 to 18 years of age) between youth with autism spectrum disorder and youth with neurotypical development. Data on the levels of moderate-to-vigorous physical activity, light physical activity, television-, and video game-based screen time, collected as a part of the “Growing up in Ireland” study, were compared between youth with autism spectrum disorder and a propensity-matched sample of youth with neurotypical development (n = 88 per group; 176 in total). Robust regression analyses indicated that children with autism spectrum disorder became less active over time compared to children with neurotypical development and that video game screen time also differed significantly between the groups when children were 9 years old. These findings elucidate important disparities present between these groups of children during pivotal developmental times.

Investigations into the wider bioecological understanding of dental problems in early childhood are limited in national surveys. Classification tree analysis (CTA) was used to explore multilevel interactions among key aspects of child and primary caregiver (PCG) psychosocial and physical health affecting dental problems in preschool children. Data were derived from the Growing Up in Ireland study, a nationally representative sample of 9-mo-olds (N = 11,134) in 2007/2008 followed up at age 3 y (N = 9,793) in 2010/2011. Analysis included PCG reports of children’s dental problems, general health, temperament, emotional and behavioral difficulties, and their own general health, stress and depression, relationship, and sociodemographic variables. Misclassification costs were specified for the model by applying a higher penalty for misclassifying those with a dental problem (minority class). Logistic regression analyses were carried out for comparison. Dental problems were reported among 302 infants (2.7%) at 9 mo of age and 493 children (5.0%) at 3 y. CTA identified infant temperament (Infant Characteristics Questionnaire unpredictable) as the primary predictor of dental problems at 9 mo and child global health at 3 y of age. First-level predictors were PCG depression score and use of a soother at 9 mo and PCG ethnicity and unscheduled hospital visits at 3 y of age. Regression analyses results supported the most important predictors at 9 mo and 3 y of age. The CTA model for 9-mo-old infants had a specificity of 90.4%, sensitivity of 31.2%, and overall accuracy of 88.8% while that for 3-y-olds had a specificity of 58.5%, sensitivity of 66%, and overall accuracy of 59%. Key aspects of infant/child and PCG health, as well as psychosocial characteristics associated with reported dental problems, should be considered in future multidisciplinary approaches to child health.

Knowledge Transfer Statement: The results of this data analysis should help raise awareness among clinicians of how primary caregiver and child psychosocial and general health factors are associated with early childhood dental problems, even before the primary dentition is complete. Classification tree analysis visually demonstrates how factors such as infant temperament (9 mo) and child global health (3 y) can interact at multiple levels and affect different subgroups of the child population. Future intervention strategies for oral health should involve consideration of the psychological and general health characteristics of the young child and PCG at both the patient and population levels. This knowledge could assist decision makers adopt an integrated multidisciplinary approach in formulating a coherent oral health policy for preschool children.

This study uses a nationally representative sample of 9-month-old infants and their families from the Growing Up in Ireland (GUI) study to investigate if reading to infants is associated with higher scores on contemporaneous indicators of cognitive development independently of other language-based interactions between parent and infant, such as showing them pictures or talking to them. Reading to infants had an independent positive effect on scores for both the problem-solving and communication subscales of the Ages and Stages Questionnaire (ASQ), while the positive effect of showing pictures was independent only for communication scores. The effects of both of these activities were, however, less substantial than the positive effect observed for the more informal activity of frequently talking to the infant while doing other things; and this was observed for both communication and problem-solving. The analyses were robust to adjustment for several other factors including maternal education, gestational age, non-parental care, breastfeeding, attachment and presence of siblings. The findings highlight the potential of reading and talking to infants, not just for language and literacy development but also for other aspects of cognitive development.

In the current study, we investigated the developmental dynamics between positive youth development, being bullied in adolescence, gender, and sociocultural risk factors. Participants were 3,509 males (49%) and 3,656 females (51%) studied longitudinally across the ages of 9, 13, and 17 years in the Growing Up in Ireland study. Using structural equation modeling, we discovered that being bullied in early adolescence was most strongly predicted by having fewer close friends, higher family poverty, and living in neighborhoods with higher levels of disorder. However, the social disadvantage of a young person’s school did not impact being bullied. More positive reports of connection and caring in early adolescence were negatively predicted by neighborhood disorder and family poverty, and being female had positive association with relationships with teachers. Developing confidence, competence, and character in late adolescence was notably related to having fewer experiences of family trauma and transitions in childhood and to having higher levels of rapport with parents in early adolescence. The results highlight the importance of studying relationships and psychological development in sociocultural context.

Background
Chronic illness in childhood is associated with worse educational outcomes. The association is usually explained via lowered cognitive development, decreased readiness to learn and school absence. However, this paper examines whether worse psychological adjustment may also play a role.

Methods
We use data from the Growing Up in Ireland study, a cohort study, which collected data on 8,568 nine-year-old children through the Irish national school system using a two-stage sampling method. Maximum likelihood path analytic models are used to assess the direct effect of child chronic illness on reading and maths test scores and the mediating role of emotional and behavioural problems.

Results
In unadjusted analyses, children with a mental and behavioural condition scored 14.5 % points less on reading tests and 16.9 % points less on maths tests than their healthy peers. Children with non-mental and behavioural conditions scored 3 % points less on both tests, a significant difference. Mental and behavioural (OR, 9.58) and other chronic conditions (OR, 1.61) were significantly more likely to have ‘high’ levels of difficulties on the SDQ. Path analysis models showed that the association between chronic illness and educational test scores was completely mediated by emotional and behavioural problems controlling for school absence and bullying by peers.

Conclusions
Child and adolescent chronic illness can have significant effects on educational development and a long-lasting impact on future life-chances. The psychological adjustment of the child is important in mediating the effect of chronic illness on educational outcomes. Interventions should target this developmental pathway.

Purpose
We investigated the hypothesis that mode of delivery affects childhood behavior and motor development and examined whether there are sex-specific associations, i.e., whether males and females have different risk estimates.

Methods
Families with infants born between December 2007 and May 2008 (N = 11,134) were randomly selected and recruited to the Growing Up in Ireland study. Mode of delivery was classified into spontaneous vaginal delivery; instrumental vaginal delivery; emergency Cesarean section (CS); and elective CS. The ‘Ages and Stages Questionnaire’ was completed at age 9-months and the ‘Strengths and Difficulties Questionnaire’ at 3 years. Data were weighted to represent the national sample (N = 73,662) and multivariate logistic regression was used for the statistical analyses.

Results
At age 9 months, elective CS was associated with a delay in personal social skills [adjusted odds ratio, aOR 1.24; (95 % confidence interval, CI 1.04, 1.48)] and gross motor function [aOR 1.62, (95 % CI 1.34, 1.96)], whereas emergency CS was associated with delayed gross motor function [aOR 1.30, (95 % CI 1.06, 1.59)]. At age 3 years there was no significantly increased risk of an abnormal total SDQ score across all modes of delivery.

Conclusions
Children born by elective CS may face a delay in cognitive and motor development at age 9 months. No increase in total SDQ score was found across all modes of delivery. Further investigation is needed to replicate these findings in other populations and explore the potential biological mechanisms.

Aims
This study aims to replicate Przybylski and Weinstein (Psychol Sci 28(2):204–215, 2017), using a large population cohort to examine the validity of the proposed Goldilocks Hypothesis, which states that moderate digital media engagement may be beneficial and that both high and low usage may have a negative relationship with mental wellbeing.

Methods
Using the GUI98 cohort, we used separate weekday and weekend time-based categorical variables indicating time spent online, playing video games, watching TV/films as well as a frequency variable indicating multiscreening, and their associations with SDQ internalizing and externalizing symptoms using linear and quadratic regression parameters. We followed procedures for confounder adjustments outlined in Przybylski and Weinstein (Psychol Sci 28(2):204–215, 2017).

Results
As hypothesized by the Goldilocks Hypothesis, time spent online watching TV/films at the weekend and multiscreening all had curvilinear relationships with internalizing and externalizing symptoms with significantly higher symptoms for no time as well as for higher exposures. internalizing and externalizing symptoms increased with time spent playing video games.

Conclusions
This brief report supports the Goldilocks Hypothesis, that suggests that moderate use of digital technology is not intrinsically harmful and may instead be beneficial, even necessary in a world becoming ever more increasingly reliant on digital media (Przybylski and Weinstein in Psychol Sci 28(2):204–215, 2017).

Purpose
The aim of this study is to examine the association between household energy poverty (EP) and trajectories of emotional and behavioural difficulties during childhood.

Methods
The Growing up in Ireland study is two nationally representative prospective cohorts of children. The Infant Cohort (n = 11,134) were recruited at age 9 months (9 m) and followed up at 3, 5, 7 and 9 years (y). The Child Cohort (n = 8,538) were recruited at age 9 y and followed up at 13 y and 17/18 y. EP was a composite of two relative measures of EP. Emotional and behavioural difficulties were repeatedly measured using the strengths and difficulties questionnaire (SDQ). Linear spline multilevel models were used, adjusted for confounders to examine the association between (1) EP (9 m or 3 y) and trajectories of emotional and behavioural difficulties from 3 to 9 y in the Infant Cohort and (2) EP at 9 y and the same trajectories from 9 to 18 y in the Child Cohort.

Results
In adjusted analyses, EP at 9 m or 3 y of age was associated with higher total difficulties score at 3 y (0.66, 95% CI 0.41, 0.91) and 5 y (0.77, 95% CI 0.48, 1.05) but not at 7 y or 9 y. EP at 9 y was associated with higher total difficulties score at 9 y (1.73, 95% CI 1.28, 2.18), with this difference reducing over time leading to 0.68 (95% CI 0.19, 1.17) at 17/18 y.

Conclusions
Our study demonstrates a potential association between early life EP and emotional and behavioural difficulties that may be transient and attenuate over time during childhood. Further studies are required to replicate these findings and to better understand if these associations are causal.

Specific pregnancy complications, socioeconomic position and sex have all been independently associated with child mental health outcomes, but their combined effects remain unclear. We examined whether total number of complications experienced in the pregnancy associated with mental health at 5 and 9-years, and whether this varied by sex or adverse social circumstances. Pregnancy complications were self-reported at 9-months post-natally from a list of 16 complications. Parents completed the Strengths and Difficulties Questionnaire (SDQ) when their child was 5 and 9-years. The primary outcome was the SDQ-total and scoring in the clinical range (> 16) was a secondary outcome. We applied generalized linear mixed models to a large nationally representative Irish cohort (GUI; n = 11,134). Analyses were adjusted for sex, adverse social circumstances (at 9-months), and gestational smoking. We included an interaction term between pregnancy complications and each variable respectively in separate models to examine if associations varied by sex or adverse circumstances.

After controlling for covariates, total complications associated with mental health at 5 and 9-years. Each additional pregnancy complication conferred a 10% higher total-SDQ score (exponentiated co-efficient 1.10 [95%CI 1.06–1.14], 1.20 [1.15–1.26], 1.20 [1.12–1.29] and 1.34 [1.21–1.48] for 1, 2, 3 and 4 + complications respectively). For the dichotomised outcome, generally increasing odds for clinical levels of mental health difficulties were observed (OR 1complication = 1.89, 95%CI [1.37–2.59]; OR 2complications = 2.31, 95%CI [1.53–3.50]; OR 3complications = 1.77, 95%CI [0.89–3.52]; OR 4 + complications = 6.88, 95%CI [3.29–14.40]). Females had significantly lower odds of exhibiting clinically significant mental health difficulties than males (OR = 0.43, 95%CI[0.32–0.57]).

There was no evidence that the association between pregnancy complications and child’s mental health varied by sex or social circumstances at 5 or 9-years. Males exposed to numerous pregnancy complications in the context of adverse social circumstances had the highest predicted probability of having mental health difficulties in middle childhood.