From infancy to eight: How early maternal mental health, emotion reminiscing, and language shape children's mental health.

To test the transmission of mental health difficulties from mother to child, we examined mediation through emotion reminiscing conversations and child language. Maternal depression symptoms were measured at 9 months post-partum, and child mental health outcomes were measured at age 8 years. Emotion reminiscing conversations between 1,234 mother-child pairs (624 boys, 610 girls) were recorded as part of a large, diverse, longitudinal cohort Growing Up in New Zealand. The 1,234 reminiscing conversations were transcribed and coded for maternal elaboration and emotion resolution quality (mother and child). The coded reminiscing variables did not mediate the pathway from maternal depression to child mental health outcomes; however, each maternal reminiscing variable together with child language skill serially mediated the relationship from maternal depression symptoms to child-reported anxiety and depression symptoms, and parent-reported child externalizing symptoms. Language as a skill and it's use as a tool for making shared meaning from past events are highlighted as possible mechanisms for the intergenerational transmission of mental health difficulties. These findings point to potential opportunities for early interventions, including prevention of and support for postnatal depression, family intervention in reminiscing training, and supporting child language development.

Prevalence and maternal determinants of early and late introduction of complementary foods: results from the Growing Up in New Zealand cohort study.

A nationally generalisable cohort (n 5770) was used to determine the prevalence of non-timely (early/late) introduction of complementary food and core food groups and associations with maternal sociodemographic and health behaviours in New Zealand (NZ). Variables describing maternal characteristics and infant food introduction were sourced, respectively, from interviews completed antenatally and during late infancy. The NZ Infant Feeding Guidelines were used to define early (≤ 4 months) and late (≥ 7 months) introduction. Associations were examined using multivariable multinomial regression, presented as adjusted relative risk ratios and 95 % confidence intervals (RRR; 95% CI). Complementary food introduction was early for 40·2 % and late for 3·2 %. The prevalence of early food group introduction were fruit/vegetables (23·8 %), breads/cereals (36·3 %), iron-rich foods (34·1 %) and of late were meat/meat alternatives (45·9 %), dairy products (46·2 %) and fruits/vegetables (9·9 %). Compared with infants with timely food introduction, risk of early food introduction was increased for infants: breastfed < 6months (2·52; 2·19-2·90), whose mothers were < 30 years old (1·69; 1·46-1·94), had a diploma/trade certificate v. tertiary education (1·39; 1·1-1·70), of Maori v. European ethnicity (1·40; 1·12-1·75) or smoked during pregnancy (1·88; 1·44-2·46). Risk of late food introduction decreased for infants breastfed < 6 months (0·47; 0.27-0·80) and increased for infants whose mothers had secondary v. tertiary education (2·04; 1·16-3·60) were of Asian v. European ethnicity (2·22; 1·35, 3·63) or did not attend childbirth preparation classes (2·23; 1·24-4·01). Non-timely food introduction, specifically early food introduction, is prevalent in NZ. Interventions to improve food introduction timeliness should be ethnic-specific and support longer breast-feeding.

Proximal Processes and Contextual Factors Associated with Early Socio-emotional Competence Development.

There is growing interest in child socio-emotional competence from parents, educators, employers and policy makers, with emphasis on developing it as early as possible. The aim of the present study was to examine contextual and proximal factors that influence socio-emotional competence development across the first five years of a child's life. We used data from 3200 mothers and their children drawn mostly from four major data collection waves (antenatal, 9 months, 2 years and 4.5 years) of the population-based longitudinal study, Growing Up in New Zealand. Regression analyses were carried out to identify the predictors of socio-emotional competence after controlling for demographics and prior score(s) of socio-emotional competence. We found that specific maternal behaviours, such as playing games and playing with toys with children, singing songs or telling stories to them, reading books with them, having rules around viewing TV, DVDs and videos, and praising children have a positive effect on socio-emotional competence. Parental relationship warmth and less family stress at 9 months also made positive contributions to socio-emotional competence at 9 months and 2 years. In contrast, attending childcare and having more siblings at home negatively predicted socio-emotional competence at 9 months. Mother's unemployment, living in neighbourhoods perceived as negative and being in contact with family and social services were negatively associated with concurrent socio-emotional competence at 2 years. Overall, more and/or stronger contemporaneous effects were found suggesting that negative effects of contextual factors may not have lasting impact on socio-emotional competence. In addition, the results showed that maternal behaviours need to be practised regularly to have positive impact on child's socio-emotional development.

An index measuring adherence to New Zealand Infant Feeding Guidelines has convergent validity with maternal socio-demographic and health behaviours and with children's body size.

Using data from a nationally generalisable birth cohort, we aimed to: (i) describe the cohort's adherence to national evidence-based dietary guidelines using an Infant Feeding Index (IFI) and (ii) assess the IFI's convergent construct validity, by exploring associations with antenatal maternal socio-demographic and health behaviours and with child overweight/obesity and central adiposity at age 54 months. Data were from the Growing Up in New Zealand cohort (n 6343). The IFI scores ranged from zero to twelve points, with twelve representing full adherence to the guidelines. Overweight/obesity was defined by BMI-for-age (based on the WHO Growth Standards). Central adiposity was defined as waist-to-height ratio > 90th percentile. Associations were tested using multiple linear regression and Poisson regression with robust variance (risk ratios, 95 % CI). Mean IFI score was 8·2 (sd 2·1). Maternal characteristics explained 29·1 % of variation in the IFI score. Maternal age, education and smoking had the strongest independent relationships with IFI scores. Compared with children in the highest IFI tertile, girls in the lowest and middle tertiles were more likely to be overweight/obese (1·46, 1·03, 2·06 and 1·56, 1·09, 2·23, respectively) and boys in the lowest tertile were more likely to have central adiposity (1·53, 1·02, 2·30) at age 54 months. Most infants fell short of meeting national Infant Feeding Guidelines. The associations between IFI score and maternal characteristics, and children's overweight/obesity/central adiposity, were in the expected directions and confirm the IFI's convergent construct validity.

Do Patterns of Levels of Socio-emotional Competence During Early Childhood Predict Executive Function at 4.5 Years?

Socio-emotional competence and executive function both work together to meet the demands of the everyday environment. While many studies have focused on how various domains of socio-emotional competence are predicted by, or associated with executive function, the predictive influence of socio-emotional competence on executive function has largely been ignored despite strong theoretical links. In addition, contradictory information exists with regard to the divergent validity of two subtypes of executive function: cool and hot. Using data from 4839 children participating in three data collection waves (9 months, 2 years and 4.5 year) in the Growing Up in New Zealand longitudinal study, we examined how different patterns of socio-emotional competence development during the early preschool years (persistent lows, recent low, improved and no lows) related to cool and hot executive function measured at aged 4.5 using a hand clap task and a gift wrap task, respectively. Findings showed that children with persistent lows (with no improvement) in the levels of early socio-emotional competence had increased odds of having below average cool and hot executive function at 4.5 years. However, no difference was found in the influence of socio-emotional competence on cool and hot executive function. Possible explanations for these associations between socio-emotional competence and executive function are discussed.

The Association Between Persistence and Change in Behavioral Difficulties During Early to Middle Childhood and Cognitive Abilities at Age 8.

We investigated the association between persistence and change in behavioral difficulties during early to middle childhood and several cognitive outcomes. We observed 3904 8-year-olds enrolled in the longitudinal study Growing Up in New Zealand (50% male/female; 23% Maori, 9% Pacific Peoples, 13% Asian, 2% Middle Eastern/Latin American/African, 9% Other, 43% European). The NIH Toolbox Cognition Battery was used to assess cognitive functioning at 8 years and the Strengths and Difficulties Questionnaire for behavioral difficulties at 4.5 and 8 years. Multivariate logistic regression analyses were conducted, controlling for well-known sociodemographic confounders. Children with persistent or later onset of behavioral difficulties were at higher risk for poorer vocabulary, reading, inhibitory control/attention, episodic memory, working memory and processing speed at age 8 compared to children with no or improved difficulties. Our study supports the importance of addressing both cognitive and behavioral aspects when planning educational programmes and interventions in early and middle childhood.

Demographic discrepancies between administrative-prioritisation and self-prioritisation of multiple ethnic identifications.

Ethnic classification is an inherently subjective process, especially when multiple ethnic identifications are involved. There are two methods commonly used to classify multiple ethnicities into single categories: administrative-prioritisation (assignment via a predetermined hierarchy) and self-prioritisation (where individuals select their "main" ethnicity). Currently, little is known about whether the demographic composition of outputted ethnic groups differs by prioritisation method. This study utilised large-scale data of multi-ethnic children (N = 1,860), adolescents (N = 2,413), and adults (N = 1,056) from Aotearoa New Zealand to examine individual and contextual demographic characteristics associated with discrepancies between administratively-prioritised and self-prioritised ethnicity. Results showed that discrepancy rates, which exceeded 50%, were systematically associated with neighbourhood ethnic composition and socioeconomic deprivation, but largely not associated with gender, age, and birthplace. The contextual nature of self-prioritisation highlights the importance of researchers' choice of ethnic classification method. Implications are discussed in the context of increasing multi-ethnic prevalence.

Child feeding indexes measuring adherence to New Zealand nutrition guidelines: Development and assessment.

New Zealand (NZ) lacks nationally representative or generalisable information on the dietary intakes of pre-schoolers. We used Growing Up in New Zealand cohort data to i) develop child feeding indexes (CFIs) based on National Food and Nutrition Guidelines for 2- and 4.5-year-olds; ii) describe the cohort adherence to the guidelines at 2 (n = 6046) and 4.5 years (n = 5889) and; iii) assess the CFIs' convergent construct validity, by exploring associations with maternal sociodemographic and health behaviours and with child body mass index for age (BMI/age) and the waist-to-height ratio at 4.5 years. The CFIs scores ranged from 0 to 11, with 11 representing full adherence to the guidelines. Associations were tested using multiple linear regressions and Poisson regressions with robust variance (risk ratios [RR], 95% confidence intervals, 95% CI). The CFIs mean scores (SD) at 2 and 4.5 years were, respectively, 6.13 (1.21) and 6.22 (1.26) points. Maternal characteristics explained, respectively, 27.2% and 31.9% of the variation in the CFIs scores at 2 and 4.5 years. In the adjusted model at the 4.5-year interview, in relation to girls ranked in the 5th quintile, those in the 2nd (RR, 95% CI: 1.48; 1.03; 1.24) and 4th (1.53; 1.05; 2.23) quintiles of the CFI were more likely to have BMI/age > +2z (World Health Organization growth standards) at 4.5 years. At 2 and 4.5 years, most children fell short of meeting national guidelines. The associations between the CFIs scores at both time points with maternal characteristics and with children's body size at 4.5 years were in the expected directions, confirming the CFIs' convergent construct validity among NZ pre-schoolers.

Exploring the Factor Structure of the NIH Toolbox Cognition Battery in a Large Sample of 8-Year-Old Children in Aotearoa New Zealand.

OBJECTIVE: The objective of this study was to derive a factor structure of the measures of the National Institutes of Health (NIH) Toolbox Cognition Battery (CB) that is representative of cognitive abilities in a large ethnically diverse cohort of 8-year-old children in Aotearoa New Zealand. METHODS: Our sample comprised of 4298 8-year-old children from the Growing Up in New Zealand study. We conducted exploratory and confirmatory factor analysis for the NIH Toolbox CB measures to discover the best-fitting factor structure in our sample. Measurement invariance of the identified model was tested across child's gender, socio-economic status (SES), and ethnicity. RESULTS: A three-dimensional factor structure was identified, with one factor of Crystallised Cognition (Reading and Vocabulary), and two distinguished factors of fluid cognition: Fluid Cognition I (Attention/Inhibitory Control, Processing Speed, and Cognitive Flexibility) and Fluid Cognition II (Working Memory, Episodic Memory). The results demonstrate excellent model fit, but reliability of the factors was low. Measurement invariance was confirmed for child's gender. We found configural, but neither metric nor scalar, invariance across SES and the four major ethnic groups: European, Maori, Pacific Peoples, and Asian. CONCLUSION: Our findings show that, at the age of 8 years, fluid abilities are more strongly associated with one another than with crystallised abilities and that fluid abilities need to be further differentiated. This dimensional structure allows for comparisons across child's gender, but evaluations across SES and ethnicity within the Aotearoa New Zealand context must be conducted with caution. We recommend using raw scores of the individual NIH Toolbox CB measures in future research.

Vitamin D status at birth and acute respiratory infection hospitalisation during infancy.

BACKGROUND: Hospital admission for acute respiratory infections (ARIs) during early childhood is a global public health concern. Vitamin D deficiency is prevalent during pregnancy and infancy. Evidence indicates that vitamin D supplementation prevents ARIs. OBJECTIVES: To determine whether vitamin D deficiency at birth is associated with ARI hospitalisations during infancy. METHODS: We performed a nested case-control study in children aged 0-12 months. Cases had ≥1 ARI hospitalisation and 4 controls were individually matched to each case. Newborn 25(OH)D concentration was measured on dried blood spots using two-dimensional liquid chromatography-tandem mass spectrometry. Hospital admissions were measured using health care records. Median serum 25(OH)D concentration in cases and controls was compared, and covariates of ARI hospitalisation during infancy were assessed using conditional logistic regression analysis. RESULTS: Six per cent of the cohort (n = 384) had an ARI hospitalisation during infancy, and 1536 controls were matched to cases. Median DBS [25(OH)D] was lower among ARI cases than controls (46 nmol/l vs. 61 nmol/L). Median 25(OH)D levels were lower for those hospitalised ≥2 times (47, IQR 36, 58) vs. those hospitalised once (52, IQR 42, 62) vs. the controls and also lower for those who stayed in the hospital for ≥3 days (45, IQR 36, 54) vs 1-2 days (48, IQR 38, 59) compared to the controls. After adjustment for season of birth and covariates describing demographic, antenatal, perinatal, and infant characteristics, DBS 25(OH)D concentration (<50 nmol/L) at birth was associated with increased odds of ARI hospitalisation during infancy (odds ratio 2.20, 95% confidence interval 1.48, 2.91). CONCLUSIONS: Vitamin D deficiency at birth is associated with increased odds of ARI hospitalisations in infants. The findings have implications for a developed country like New Zealand where vitamin D supplementation is not routinely recommended and the burden of ARI hospitalisation in young children is high.

Patterns of risk exposure in first 1,000 days of life and health, behavior, and education-related problems at age 4.5: evidence from Growing Up in New Zealand, a longitudinal cohort study.

BACKGROUND: Children who are high priority candidates for early intervention need to be identified to reduce their risk for experiencing problems in development. Those exposed to multiple risk factors are more likely to exhibit problems in development than those exposed to a single or no risk factor. We examined the longitudinal associations between persistence and timing of exposure to cumulative risk (CR) on three occasions by age 2 and problems in development at age 4.5 in health, behavior, and education-related domains. METHODS: Data are from Growing Up in New Zealand (NZ), a prospective longitudinal study of a birth cohort first assessed during their last trimester in 2009-10 and followed at ages 9 months and 2 and 4.5 years. All women with an expected delivery date in a 12-month period who resided within a defined region were invited to participate, with no additional eligibility criteria. Exposure was measured for 12 sociodemographic and maternal health risk factors at third trimester and ages 9 months and 2 years, from which developmental trajectories were constructed capturing persistence and timing of CR exposure. Ten developmental outcomes were measured at age 4.5 to classify problems in overall health status, obesity, and injuries; internalizing and externalizing behavior problems; and letter naming, counting forward and backward, and expectations for starting school and completing education. RESULTS: Analyses of data from 6156 children (49% female, 33% Non-European ethnicity) who participated in the 4.5-age assessment uniformly showed associations between exposure to more than consistently zero CR across early development and higher prevalence of being classified with problems for 9 of 10 outcomes. Persistent exposure to a CR ≥ 4 was generally associated with a higher prevalence of problems for 7 of 10 outcomes, whereas the timing of first exposure to CR ≥ 4 showed a less consistent association with problem outcomes. CONCLUSIONS: These findings are concerning because over 50% of NZ children are exposed to at least one of these risk factors at some point in early development. Routine screening of most of these risk factors during pregnancy is feasible and can identify priority candidates for intervention.

Maternal Antenatal Depression and Early Childhood Sleep: Potential Pathways Through Infant Temperament.

OBJECTIVE: Maternal depression is associated with infant and child sleep patterns, and with infant temperament. Here, we examine whether infant temperament mediated an association between maternal antenatal depression and toddler sleep. METHOD: Within the prebirth longitudinal cohort Growing Up in New Zealand, symptoms of antenatal and postnatal depression were measured in 5,568 women using the Edinburgh Postnatal Depression Scale (EPDS). Infant temperament was measured at age 9 months using the Very Short Form of Infant Behavior Questionnaire-Revised (IBQ-R VSF). Sleep duration and nighttime awakenings were reported by parents when children were 2 years old. RESULTS: Independent associations of maternal depression with child sleep patterns at age 2 years, adjusted for maternal demographics, physical health, family relationships, and child health and feeding, were determined using multivariate logistic regression analysis. The odds of having ≥2 nighttime awakenings were increased for children whose mothers had antenatal (1.36, 1.07-1.73) but not postnatal (1.22, 0.88-1.68) or both antenatal and postnatal depression (0.89, 0.56-1.36). There was no association of maternal depression with shorter sleep duration. Two of five dimensions of infant temperament (fear and negative affect) were associated with both antenatal depression scores and increased nighttime awakenings. Mediation analyses controlling for postnatal depression and other predictors of child sleep supported an indirect pathway of antenatal depression to child sleep through infant temperamental negative affectivity. CONCLUSION: Antenatal depression is independently associated with more frequent nighttime awakenings in early childhood. Findings support an indirect pathway through infant negative affect characteristics.

The Association Between Persistence and Change in Early Childhood Behavioural Problems and Preschool Cognitive Outcomes.

The link between behavioural and cognitive difficulties is well established. However, research is limited on whether persistence and change in behavioural difficulties relates to cognitive outcomes, particularly during preschool. We used a large New Zealand birth cohort to investigate how persistence and change in serious behavioural problems from ages 2 to 4.5 years related to measures of cognitive delay at 4.5 years (n = 5885). Using the Strengths and Difficulties total problems score at each time point, children were categorised as showing no difficulties, improved behaviour, concurrent difficulties, and persistent difficulties. Cognitive measures assessed included receptive language, early literacy ability, and executive control. Our results showed that children with concurrent and persistent behavioural difficulties were at a greater risk of showing delays within specific cognitive domains relative to children with no difficulties and were also more likely to show comorbid delays across multiple cognitive domains.

Decomposing ethnic differences in body mass index and obesity rates among New Zealand pre-schoolers.

OBJECTIVE: To determine the extent to which ethnic differences in BMI Z-scores and obesity rates could be explained by the differential distribution of demographic (e.g. age), familial (e.g. family income), area (e.g. area deprivation), parental (e.g. immigration status), and birth (e.g. gestational age) characteristics across ethnic groups. METHODS: We used data on 4-year-old children born in New Zealand who attended the B4 School Check between the fiscal years of 2010/2011 to 2015/2016, who were resident in the country when the 2013 census was completed (n = 253,260). We implemented an Oaxaca-Blinder decomposition to explain differences in BMI Z-score and obesity between Maori (n = 63,061) and European (n = 139,546) children, and Pacific (n = 21,527) and European children. RESULTS: Overall, 15.2% of the children were obese and mean BMI Z-score was 0.66 (SD = 1.04). The Oaxaca-Blinder decomposition demonstrated that the difference in obesity rates between Maori and European children would halve if Maori children experienced the same familial and area level conditions as Europeans. If Pacific children had the same characteristics as European children, differences in obesity rates would reduce by approximately one third, but differences in mean BMI Z-scores would only reduce by 16.1%. CONCLUSION: The differential distribution of familial, parental, area, and birth characteristics across ethnic groups explain a substantial percentage of the ethnic differences in obesity, especially for Maori compared to European children. However, marked disparities remain.

Persistence and change in behavioural problems during early childhood.

BACKGROUND: Behavioural problems and psychopathology can present from as early as the preschool period. However there is evidence that behavioural difficulties may not be stable over this period. Therefore, the current study was interested in evaluating the persistence and change in clinically relevant behavioural problems during early childhood in a population-based New Zealand birth cohort. METHODS: Behaviour was assessed in 5896 children when they were aged 2 and 4.5 years using the Strengths and Difficulties Questionnaire (SDQ). Correlations and mean differences in subscale and total difficulties scores were examined. Scores were then dichotomised into normal/borderline and abnormal ranges to evaluate the persistence and change in significant behavioural problems. Chi-square analyses and ANOVAs were used to determine the association between sociodemographic and birth variables, and preschool behavioural stability. RESULTS: Raw scores at ages 2 and 4.5 years were moderately correlated, with most measures showing a small but significant decrease in mean scores over time. The majority of children who showed abnormal behaviour at 2 years improved at 4.5 years (57.9% for total difficulties). However, a notable proportion persisted in their difficulties from 2 to 4.5 years (42.1% for total difficulties). There was a small percentage of children who were categorised as abnormal only at 4.5 years. Children with difficulties at one or both time points had a greater proportion who were the result of an unplanned pregnancy, lived in highly deprived urban areas, and had mothers who were younger, of Maori and Pacific ethnicity and were less educated. CONCLUSIONS: Not all children who show early behavioural difficulties persist in these difficulties. Those whose difficulties persist were more likely to experience risk factors for vulnerability relative to children with no difficulties. Results suggest that repeated screening for early childhood behavioural difficulties is important.

Antenatal and Postnatal Determinants of Behavioural Difficulties in Early Childhood: Evidence from Growing Up in New Zealand.

Behavioural difficulties during early childhood have significant implications for multiple outcomes later in life. Child behavioural difficulties at 2 years of age (N = 6246) were assessed by mothers enrolled in a longitudinal, population-based New Zealand cohort study. 10.1% of children had total difficulties scores in the abnormal range on the preschool version of the Strengths and Difficulties Questionnaire. After controlling for maternal education, poverty, and child's birth age/weight, several antenatal and postnatal maternal health and family risk factors were significant for: (i) emotional problems (antenatal maternal perceived stress, lack of periconceptional folate, and moderate to severe maternal postnatal anxiety); (ii) hyperactivity-inattention (antenatal maternal perceived stress, mothers' antenatal exposure to secondhand smoke, moderate to severe maternal postnatal anxiety, and low maternal self-evaluation); (iii) conduct problems and total difficulties (antenatal maternal perceived stress, verbal inter-parental conflict and low maternal self-evaluation). The identification of risk and protective factors associated with early childhood difficulties are vital for guiding intervention and prevention efforts.

Staphylococcus aureus colonisation and its relationship with skin and soft tissue infection in New Zealand children.

New Zealand children suffer from high rates of skin and soft tissue infection (SSTI). Staphylococcus aureus colonisation is known to increase the risk of nosocomial infection. We aimed to determine whether S. aureus colonisation also increased the risk of community-onset SSTI. This study, performed within the Growing Up in New Zealand cohort, used interview and administrative data, and bacterial culture results from the nose, throat, and skin swabs collected at 4½ years of age. Multivariable log-binomial regression was used to derive adjusted risk ratios. S. aureus was isolated from 2225/5126 (43.4%) children. SSTI affected 1509/5126 (29.4%) children before age five. S. aureus colonisation at any site was associated with SSTI (aRR = 1.09, 95%CI 1.01-1.19), particularly in the year prior to swab collection (aRR = 1.18, 95%CI 1.02-1.37). The strongest association was between skin colonisation and SSTI within the year prior to swab collection (aRR = 1.47, 95%CI 1.14-1.84). Socioeconomic and ethnic variables remained independent determinants of SSTI. S. aureus colonisation was associated with an increased risk of community-onset SSTI. Socioeconomic and ethnic factors and eczema had independent effects on SSTI risk. Interventions which reduce the prevalence of S. aureus colonisation may be expected to reduce the incidence of community-onset SSTI.

How differing methods of ascribing ethnicity and socio-economic status affect risk estimates for hospitalisation with infectious disease.

Significant ethnic and socio-economic disparities exist in infectious diseases (IDs) rates in New Zealand, so accurate measures of these characteristics are required. This study compared methods of ascribing ethnicity and socio-economic status. Children in the Growing Up in New Zealand longitudinal cohort were ascribed to self-prioritised, total response and single-combined ethnic groups. Socio-economic status was measured using household income, and both census-derived and survey-derived deprivation indices. Rates of ID hospitalisation were compared using linked administrative data. Self-prioritised ethnicity was simplest to use. Total response accounted for mixed ethnicity and allowed overlap between groups. Single-combined ethnicity required aggregation of small groups to maintain power but offered greater detail. Regardless of the method used, Maori and Pacific children, and children in the most socio-economically deprived households had a greater risk of ID hospitalisation. Risk differences between self-prioritised and total response methods were not significant for Maori and Pacific children but single-combined ethnicity revealed a diversity of risk within these groups. Household income was affected by non-random missing data. The census-derived deprivation index offered a high level of completeness with some risk of multicollinearity and concerns regarding the ecological fallacy. The survey-derived index required extra questions but was acceptable to participants and provided individualised data. Based on these results, the use of single-combined ethnicity and an individualised survey-derived index of deprivation are recommended where sample size and data structure allow it.

Antibiotic consumption by New Zealand children: exposure is near universal by the age of 5 years.

Background: Increasing concerns about antibiotic resistance and microbiome disruption have stimulated interest in describing antibiotic consumption in young children. Young children are an age group for whom antibiotics are frequently prescribed. Objectives: To describe community antibiotic dispensing during the first 5 years of life in a large, socioeconomically and ethnically diverse cohort of children, and to determine how antibiotic dispensing varied between population subgroups. Methods: This study was performed within the Growing Up in New Zealand longitudinal cohort study ( www.growingup.co.nz ) with linkage to national administrative antibiotic dispensing data. Descriptive statistics and univariate and multivariable associations were determined. Results: The 5581 cohort children received 53 052 antibiotic courses, of which 54% were amoxicillin. By age 5 years, 97% of children had received one or more antibiotic courses, and each child had received a median of eight antibiotic courses (IQR 4-13). The mean incidence of antibiotic dispensing was 1.9 courses/child/year. Multivariable negative binomial regression showed that Maori and Pacific children received more antibiotic courses than European children, as did children in the most-deprived compared with the least-deprived areas. A distinct seasonal pattern was noted. Conclusions: This study provided a detailed description of antibiotic dispensing within a large and diverse child cohort. Antibiotic exposure was near universal by age 5 years. The predominance of amoxicillin use and the seasonal pattern suggest much antibiotic use may have been for self-limiting respiratory infections. There is a need for safe and effective interventions to improve antibiotic prescribing practices for New Zealand children.

A Longitudinal Study of Pre-pregnancy and Pregnancy Risk Factors Associated with Antenatal and Postnatal Symptoms of Depression: Evidence from Growing Up in New Zealand.

Objectives Antenatal and postnatal depression can lead to poor outcomes for women and their children. The aim of this study was to explore whether risk factors differ for depression symptoms that are present during pregnancy and/or after childbirth. Methods An ethnically and socioeconomically diverse sample of 5301 women completed interviews during the third trimester of pregnancy and 9 months after childbirth. Depression symptoms were measured using the Edinburgh Postnatal Depression Scale (EPDS). Depression symptoms (defined as EPDS >12) among participants and associations with pre-pregnancy and pregnancy maternal characteristics were explored using logistic regression. Results The rate of antenatal depression symptoms (ADS) only was 8.5, 5% of women had depression symptoms at 9 months postpartum (PDS) only and 3% experienced depression symptoms at both time points. Perceived stress and Pacific or Asian ethnicity were risk factors for ADS and PDS. Anxiety during and before pregnancy was a risk factor for ADS only while having a pre-pregnancy diagnosis of depression was a risk factor for PDS only. Having ADS increased the odds ratio of PDS by 1.5 (95% CI 1.01-2.30). Conclusions The results supported evidence from previous longitudinal studies that depression symptoms appear to be higher during pregnancy than in the first year following childbirth. The study found that PDS may often be a continuation or recurrence of ADS.