Change in the food environment and measured adiposity in adulthood in the Christchurch Health and development birth cohort, Aotearoa, New Zealand: A birth cohort study

This study investigated associations between change in the food environment and change in measured body mass index (BMI) and waist circumference (WC) in the Christchurch Health and Development Study (CHDS) birth cohort. Our findings suggest that cohort members who experienced the greatest proportional change towards better access to fast food outlets had the slightly larger increases in BMI and WC. Contrastingly, cohort members who experienced the greatest proportional change towards shorter distance and better access to supermarkets had slightly smaller increases in BMI and WC. Our findings may help explain the changes in BMI and WC at a population level.

DNA methylation patterns at birth predict health outcomes in young adults born very low birthweight

Background

Individuals born very low birthweight (VLBW) are at increased risk of impaired cardiovascular and respiratory function in adulthood. To identify markers to predict future risk for VLBW individuals, we analyzed DNA methylation at birth and at 28 years in the New Zealand (NZ) VLBW cohort (all infants born < 1500 g in NZ in 1986) compared with age-matched, normal birthweight controls. Associations between neonatal methylation and cardiac structure and function (echocardiography), vascular function and respiratory outcomes at age 28 years were documented.

Results

Genomic DNA from archived newborn heel-prick blood (n = 109 VLBW, 51 controls) and from peripheral blood at ~ 28 years (n = 215 VLBW, 96 controls) was analyzed on Illumina Infinium MethylationEPIC 850 K arrays. Following quality assurance and normalization, methylation levels were compared between VLBW cases and controls at both ages by linear regression, with genome-wide significance set to p < 0.05 adjusted for false discovery rate (FDR, Benjamini-Hochberg). In neonates, methylation at over 16,400 CpG methylation sites differed between VLBW cases and controls and the canonical pathway most enriched for these CpGs was Cardiac Hypertrophy Signaling (p = 3.44E⁻¹¹). The top 20 CpGs that differed most between VLBW cases and controls featured clusters in ARID3A, SPATA33, and PLCH1 and these 3 genes, along with MCF2L, TRBJ2-1 and SRC, led the list of 15,000 differentially methylated regions (DMRs) reaching FDR-adj significance. Fifteen of the 20 top CpGs in the neonate EWAS showed associations between methylation at birth and adult cardiovascular traits (particularly LnRHI). In 28-year-old adults, twelve CpGs differed between VLBW cases and controls at FDR-adjusted significance, including hypermethylation in EBF4 (four CpGs), CFI and UNC119B and hypomethylation at three CpGs in HIF3A and one in KCNQ1. DNA methylation GrimAge scores at 28 years were significantly greater in VLBW cases versus controls and weakly associated with cardiovascular traits. Four CpGs were identified where methylation differed between VLBW cases and controls in both neonates and adults, three reversing directions with age (two CpGs in EBF4, one in SNAI1 were hypomethylated in neonates, hypermethylated in adults). Of these, cg16426670 in EBF4 at birth showed associations with several cardiovascular traits in adults.

Conclusions

These findings suggest that methylation patterns in VLBW neonates may be informative about future adult cardiovascular and respiratory outcomes and have value in guiding early preventative care to improve adult health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-023-01463-3.

The long-term impacts of the Canterbury earthquakes on the mental health of the Christchurch Health and Development Study cohort

OBJECTIVE

Long-term studies following disasters are rare. It is important to quantify long-term effects of disasters to determine impacts on populations over time. We therefore aim to report the long-term associations between exposure to the Canterbury earthquakes and common mental disorders, taking into account potential confounding factors.

METHODS

The Christchurch Health and Development Study is a 40-year longitudinal study of a birth cohort of New Zealand children (635 males and 630 females). The Christchurch Health and Development Study includes 884 participants with data on earthquake exposure and mental health outcomes at ages 34 and 40 years. Rates of Diagnostic and Statistical Manual of Mental Disorders (4th ed.) disorders were measured categorically and using an expanded definition that included sub-syndromal symptoms. The current impact of the earthquakes is reported using 12-month prevalence data 7 years after the earthquakes. The cumulative impact of the earthquakes over the 7 years since onset is also reported.

RESULTS

There was a linear trend towards increasing rates of disorder with increasing exposure to the earthquakes. After adjusting for covariates, the 12-month prevalence of anxiety disorder symptoms was significantly increased (p = 0.003). The earthquakes were also associated with cumulative increases in symptoms of post-traumatic stress disorder (p < 0.001), anxiety disorder (p = 0.016), nicotine dependence (p = 0.012), and the total number of disorders (p = 0.039).

CONCLUSION

The Canterbury earthquakes were associated with persistent increases in Anxiety Disorder symptoms 7 years after their onset. The earthquakes were also associated with cumulative increases in symptoms of common psychiatric disorders. The magnitude of these effects is small, may no longer be clinically significant and has decreased over time.

Common Genetic Variation and Age of Onset of Anorexia Nervosa

Background

Genetics and biology may influence the age of onset of anorexia nervosa (AN). The aims of this study were to determine whether common genetic variation contributes to age of onset of AN and to investigate the genetic associations between age of onset of AN and age at menarche.

Methods

A secondary analysis of the Psychiatric Genomics Consortium genome-wide association study (GWAS) of AN was performed, which included 9335 cases and 31,981 screened controls, all from European ancestries. We conducted GWASs of age of onset, early-onset AN (<13 years), and typical-onset AN, and genetic correlation, genetic risk score, and Mendelian randomization analyses.

Results

Two loci were genome-wide significant in the typical-onset AN GWAS. Heritability estimates (single nucleotide polymorphism-h 2) were 0.01-0.04 for age of onset, 0.16-0.25 for early-onset AN, and 0.17-0.25 for typical-onset AN. Early- and typical-onset AN showed distinct genetic correlation patterns with putative risk factors for AN. Specifically, early-onset AN was significantly genetically correlated with younger age at menarche, and typical-onset AN was significantly negatively genetically correlated with anthropometric traits. Genetic risk scores for age of onset and early-onset AN estimated from independent GWASs significantly predicted age of onset. Mendelian randomization analysis suggested a causal link between younger age at menarche and early-onset AN.

Conclusions

Our results provide evidence consistent with a common variant genetic basis for age of onset and implicate biological pathways regulating menarche and reproduction.

Self-reported executive function problems in adults born very low birthweight

BACKGROUND

Executive function difficulties are common among children born very preterm and/or very low birthweight (<1500 g; VLBW), but little is known about whether they persist into adulthood.

OBJECTIVES

Examine the nature and pattern of self-reported executive functioning at 23 and 28 years of age using data from a national cohort study of adults born VLBW and a comparison group of same-age full-term (FT) born adults. Also examined were associations between executive function difficulties and socio-economic outcomes.

METHODS

All infants born VLBW in New Zealand during 1986 were prospectively included in an audit of retinopathy of prematurity (n = 413), with 250 (77% of survivors) followed to median age 28 years. A comparison group of FT adults was also recruited at age 23 and followed to 28 years (n = 100). Across both adult assessments, executive functioning was assessed using the Behaviour Rating Inventory of Executive Function-Adult Version (BRIEF-A) and analysed with semi-parametric models to examine the effects of age and group on executive function.

RESULTS

At 23 and 28 years, VLBW adults had increased risk of executive function impairment compared with FT adults in behaviour regulation (relative risk [CI] 2.37, 95% confidence interval (CI)1.27, 4.45), meta-cognition (RR 6.03, 95% CI 2.18, 16.78) and global functioning (RR 3.20, 95% CI 1.40, 7.28). Impaired global executive functioning was associated with lower socio-economic status (regression estimate [b] = -0.43, 95% CI -0.59, -0.27) and a reduced likelihood of home ownership by age 28 years (RR 0.98, 95% CI 0.96, 1.00), even after controlling for sex, ethnicity and parental socio-economic backgrounds for both groups.

CONCLUSION(S)

VLBW-born adults continue to experience more executive function difficulties in their everyday life relative to term controls at age 28 years. These difficulties were negatively associated with their socio-economic opportunities as young adults.

Little evidence for long-term harm from antenatal corticosteroids in a population-based very low birthweight young adult cohort

BACKGROUND

Antenatal corticosteroids (ACS) given to mothers with anticipated very preterm delivery are widely used and improve infant outcomes. Follow-up studies of the first trials of ACS have shown no adverse effects, but recently there have been concerns about possible longer-term harms.

OBJECTIVES

We aimed to assess the relationship of ACS therapy to a range of physical health and welfare measures in a cohort of very low birthweight (VLBW; <1500 g) young adults.

METHODS

Population-based cohort follow-up study. All VLBW infants born in New Zealand in 1986 were included in a prospective audit of retinopathy of prematurity. Perinatal data collection included information on ACS. At 26-30 years, 250 of 323 (77%) survivors participated, 58% having received ACS, with 229 assessed in one centre, including cardiovascular, metabolic, respiratory and neurocognitive measures. Differences in outcome between those receiving/not receiving ACS were summarised by the mean difference for continuous outcomes supplemented by Cohen's d as a standardised measure of effect size (ES), and risk ratios (RRI) for dichotomous outcomes, adjusted for relevant covariates using generalised linear regression methods.

RESULTS

There were no or minimal adverse effects of receipt of ACS versus no receipt across a range of health and welfare outcomes, both for the full cohort (adjusted ES range d = 0.01-0.23; adjusted RR range 0.78-2.03) and for individuals with gestation <28 weeks (extremely preterm; EP), except for a small increase in rates of major depression. In EP adults, receipt of ACS was associated with a higher incidence of hypertension, but might have a small benefit for IQ.

CONCLUSIONS

In this population-based VLBW cohort, we detected minimal adverse outcomes associated with exposure to ACS by the third decade of life, a similar result to the 30-year follow-up of participants in the first ACS trial. However, further follow-up is warranted.

DNA methylation analysis using bisulphite-based amplicon sequencing of individuals exposed to maternal tobacco use during pregnancy, and offspring conduct problems in childhood and adolescence

Maternal tobacco smoking during pregnancy is a large driver of health inequalities and a higher prevalence of conduct problem (CP) has been observed in exposed offspring. Further, maternal tobacco use during pregnancy can also alter offspring DNA methylation. However, currently, limited molecular evidence has been found to support this observation. Thus we aim to examine the association between maternal tobacco use in pregnancy and offspring CP, to determine whether offspring CP is mediated by tobacco exposure-induced DNA methylation differences. Understanding the etiology of the association between maternal tobacco use and offspring CP will be crucial in the early identification and treatment of CP in children and adolescents. Here, a sub group of N =96 individuals was sourced from the Christchurch Health and Development Study, a longitudinal birth cohort studied for over 40 years in New Zealand. Whole blood samples underwent bisulphite-based amplicon sequencing at 10 loci known to play a role in neurodevelopment, or which had associations with CP phenotypes. We identified significant (P CYP1A1 , ASH2L and MEF2C in individuals with CP who were exposed to tobacco in utero . We conclude that environmentally-induced DNA methylation differences could play a role in the observed link between maternal tobacco use during pregnancy and childhood/adolescent CP. However, larger sample sizes are needed to produce an adequate amount of power to investigate this interaction further.

ADHD symptoms and diagnosis in adult preterms: systematic review, IPD meta-analysis, and register-linkage study

BACKGROUND

This study examined differences in ADHD symptoms and diagnosis between preterm and term-born adults (≥18 years), and tested if ADHD is related to gestational age, birth weight, multiple births, or neonatal complications in preterm borns.

METHODS

(1) A systematic review compared ADHD symptom self-reports and diagnosis between preterm and term-born adults published in PubMed, Web of Science, and PROQUEST until April 2021; (2) a one-stage Individual Participant Data(IPD) meta-analysis (n = 1385 preterm, n = 1633 term; born 1978-1995) examined differences in self-reported ADHD symptoms[age 18-36 years]; and (3) a population-based register-linkage study of all live births in Finland (01/01/1987-31/12/1998; n = 37538 preterm, n = 691,616 term) examined ADHD diagnosis risk in adulthood (≥18 years) until 31/12/2016.

RESULTS

Systematic review results were conflicting. In the IPD meta-analysis, ADHD symptoms levels were similar across groups (mean z-score difference 0.00;95% confidence interval [95% CI] -0.07, 0.07). Whereas in the register-linkage study, adults born preterm had a higher relative risk (RR) for ADHD diagnosis compared to term controls (RR = 1.26, 95% CI 1.12, 1.41, p < 0.001). Among preterms, as gestation length (RR = 0.93, 95% CI 0.89, 0.97, p < 0.001) and SD birth weight z-score (RR = 0.88, 95% CI 0.80, 0.97, p < 0.001) increased, ADHD risk decreased.

CONCLUSIONS

While preterm adults may not report higher levels of ADHD symptoms, their risk of ADHD diagnosis in adulthood is higher.

IMPACT

Preterm-born adults do not self-report higher levels of ADHD symptoms, yet are more likely to receive an ADHD diagnosis in adulthood compared to term-borns. Previous evidence has consisted of limited sample sizes of adults and used different methods with inconsistent findings. This study assessed adult self-reported symptoms across 8 harmonized cohorts and contrasted the findings with diagnosed ADHD in a population-based register-linkage study. Preterm-born adults may not self-report increased ADHD symptoms. However, they have a higher risk of ADHD diagnosis, warranting preventive strategies and interventions to reduce the presentation of more severe ADHD symptomatology in adulthood.

Genetic association study of childhood aggression across raters, instruments, and age

Childhood aggressive behavior (AGG) has a substantial heritability of around 50%. Here we present a genome-wide association meta-analysis (GWAMA) of childhood AGG, in which all phenotype measures across childhood ages from multiple assessors were included. We analyzed phenotype assessments for a total of 328 935 observations from 87 485 children aged between 1.5 and 18 years, while accounting for sample overlap. We also meta-analyzed within subsets of the data, i.e., within rater, instrument and age. SNP-heritability for the overall meta-analysis (AGGoverall) was 3.31% (SE = 0.0038). We found no genome-wide significant SNPs for AGGoverall. The gene-based analysis returned three significant genes: ST3GAL3 (P = 1.6E-06), PCDH7 (P = 2.0E-06), and IPO13 (P = 2.5E-06). All three genes have previously been associated with educational traits. Polygenic scores based on our GWAMA significantly predicted aggression in a holdout sample of children (variance explained = 0.44%) and in retrospectively assessed childhood aggression (variance explained = 0.20%). Genetic correlations (rg) among rater-specific assessment of AGG ranged from rg = 0.46 between self- and teacher-assessment to rg = 0.81 between mother- and teacher-assessment. We obtained moderate-to-strong rgs with selected phenotypes from multiple domains, but hardly with any of the classical biomarkers thought to be associated with AGG. Significant genetic correlations were observed with most psychiatric and psychological traits (range [Formula: see text]: 0.19-1.00), except for obsessive-compulsive disorder. Aggression had a negative genetic correlation (rg = ~-0.5) with cognitive traits and age at first birth. Aggression was strongly genetically correlated with smoking phenotypes (range [Formula: see text]: 0.46-0.60). The genetic correlations between aggression and psychiatric disorders were weaker for teacher-reported AGG than for mother- and self-reported AGG. The current GWAMA of childhood aggression provides a powerful tool to interrogate the rater-specific genetic etiology of AGG.

Menopause status and climacteric symptoms in a birth cohort of mid-life New Zealand women

BACKGROUND

There is little current research on the transition to natural menopause among contemporary groups of mid-life women at age 40 years.

OBJECTIVE

This study reports on female members of the Christchurch Health and Development Study cohort. This research aimed to: document the menopause status, reproductive outcomes and climacteric symptoms of the women at age 40 years; examine the associations between menopause status and concurrent measures of psychosocial and economic well-being; and document the associations between menopause status and potential predictors of menopause reflecting childhood, family and individual factors prior to age 40 years.

METHODS

The Christchurch Health and Development Study is a longitudinal, representative, prospective cohort of 1265 babies (630 females) born in New Zealand in 1977. At age 40 years, 470 women (who had not experienced surgical menopause) were interviewed on their menopause status, climacteric symptoms and associated factors.

RESULTS

The majority of women were premenopausal, around 20% were perimenopausal and 2% were postmenopausal. Statistically significant associations were found reflecting higher rates of diagnosed reproductive disorder, climacteric symptoms, low occupational status, non-heterosexual sexuality and exposure to childhood sexual abuse amongst both perimenopausal and postmenopausal women at age 40 years.

CONCLUSION

These data will inform directions for future data collection and analyses.

Recruitment and retention of participants in longitudinal studies after a natural disaster

Climate change and population growth will increase vulnerability to natural and human-made disasters or pandemics. Longitudinal research studies may be adversely impacted by a lack of access to study resources, inability to travel around the urban environment, reluctance of sample members to attend appointments, sample members moving residence and potentially also the destruction of research facilities. One of the key advantages of longitudinal research is the ability to assess associations between exposures and outcomes by limiting the influence of sample selection bias. However, ensuring the validity and reliability of findings in longitudinal research requires the recruitment and retention of respondents who are willing and able to be repeatedly assessed over an extended period of time. This study examined recruitment and retention strategies of 11 longitudinal cohort studies operating during the Christchurch, New Zealand earthquake sequence which began in September 2010, including staff perceptions of the major impediments to study operations during/after the earthquakes and respondents' barriers to participation. Successful strategies to assist recruitment and retention after a natural disaster are discussed. With the current COVID-19 pandemic, longitudinal studies are potentially encountering some of the issues highlighted in this paper including: closure of facilities, restricted movement of research staff and sample members, and reluctance of sample members to attend appointments. It is possible that suggestions in this paper may be implemented so that longitudinal studies can protect the operation of their research programmes.

A validation of Illumina EPIC array system with bisulfite-based amplicon sequencing

The Illumina Infinium^® MethylationEPIC BeadChip system (hereafter EPIC array) is considered to be the current gold standard detection method for assessing DNA methylation at the genome-wide level. EPIC arrays are often used for hypothesis generation or pilot studies, the natural conclusion to which is to validate methylation candidates and expand these in a larger cohort, in a targeted manner. As such, an accurate smaller-scale, targeted technique, that generates data at the individual CpG level that is equivalent to the EPIC array, is needed. Here, we tested an alternative DNA methylation detection technique, known as bisulfite-based amplicon sequencing (BSAS), to determine its ability to validate CpG sites detected in EPIC array studies. BSAS was able to detect differential DNA methylation at CpG sites to a degree which correlates highly with the EPIC array system at some loci. However, BSAS correlated less well with EPIC array data in some instances, and most notably, when the magnitude of change via EPIC array was greater than 5%. Therefore, our data suggests that BSAS can be used to validate EPIC array data, but each locus must be compared on an individual basis, before being taken forward into large scale screening. Further, BSAS does offer advantages compared to the probe-based EPIC array; BSAS amplifies a region of the genome (∼500 bp) around a CpG of interest, allowing analyses of other CpGs in the region that may not be present on the EPIC array, aiding discovery of novel CpG sites and differentially methylated regions of interest. We conclude that BSAS offers a valid investigative tool for specific regions of the genome that are currently not contained on the array system.

Perinatal and childhood predictors of general cognitive outcome at 28 years in a very-low-birthweight national cohort

AIM

To determine IQ at 26 to 30 years in very-low-birthweight (VLBW) adults compared with term-born controls; and to examine the stability of IQ in VLBW individuals between 7 to 8 years and 26 to 30 years, identify perinatal and social predictors of IQ, and assess the contribution of brain volume to IQ.

METHOD

At 26 to 30 years, 229 VLBW adults (71% survivors of prospectively enrolled national cohort) and 100 term-born controls were tested on the Wechsler Abbreviated Scale of Intelligence. For VLBW, IQ at 7 to 8 years, perinatal and social data were extracted from the data set, and 150 adults underwent volumetric cranial magnetic resonance imaging (MRI).

RESULTS

At 26 to 30 years, the mean adjusted difference between VLBW and controls for total IQ was 9.4 (95% CI 6.5-12.4) points. In VLBW individuals the correlation between IQ scores at 7 to 8 years and 26 to 30 years was 0.78. On multiple regression analysis, parental education was the strongest predictor of verbal and total IQ at both ages. Birthweight was a strong predictor of perceptual and total IQ. In VLBW individuals with MRI scans, the addition of brain volume as a variable increased the variance explained for perceptual and total IQ.

INTERPRETATION

VLBW adults have mean IQ scores 9 to 11 points below controls. Parental education and birthweight are the strongest predictors of IQ.

Dental status of young adults born with very low birthweight: A national cohort study

OBJECTIVES

Little is known about the oral health of very low birthweight (<1500 g: VLBW) young adults. This study compared the oral health and self-reported oral health in a 1986 birth cohort of VLBW young adults with that of term-born controls.

METHODS

Oral health interviews and dental examinations were conducted. The dental examinations were carried out in a dental clinic using the standardized examination protocols from the 2009 New Zealand Oral Health Survey. Participants were interviewed to obtain data on self-reported oral health, oral hygiene practices, use of dental health services and oral health-related quality of life using the OHIP-14 measure.

RESULTS

Interviews were completed by 250 VLBW participants and 226 (90.4%) of those underwent the dental examination. All 100 controls completed both the interview and dental examination. While there were few overall differences in clinical or self-reported oral health between the VLBW or control groups, proportionally fewer VLBW participants attended the dentist for regular check-ups or cleaned between their teeth than controls. The VLBW and controls did not differ in the prevalence of untreated dental caries or in the number of carious tooth surfaces after adjusting for confounders. However, participants in the control group had more teeth that had been restored due to caries (4.4 teeth) than did the VLBW group (3.4 teeth, P = .045), after adjusting for confounding.

CONCLUSIONS

Very low birthweight young adults showed poorer self-care than the control group when it came to oral health; they were less likely to regularly attend dental visits, had poorer oral hygiene and were less likely to have had their dental disease treated. VLBW young adults should be encouraged to attend regular dental check-up appointments and to carry out effective home oral hygiene care.

The borderline pattern descriptor in the International Classification of Diseases, 11th Revision: A redundant addition to classification

OBJECTIVE

The International Classification of Diseases, 11th Revision classification of personality disorder removes all categories of disorder in favour of a single diagnostic spectrum extending from no personality dysfunction to severe personality disorder. Following concerns from some clinicians and Personality Disorder Societies, it was subsequently agreed to include a borderline pattern descriptor as a qualifier of the main diagnosis. We explore the value of this additional descriptor by examining personality data in patients with major depression.

METHOD

We examined personality data obtained using the Structured Clinical Interview for Personality Disorder-II in 606 patients enrolled in five randomised controlled trials of depression. The Structured Clinical Interview for Personality Disorder-II uses the Diagnostic and Statistical Manual of Mental Disorders categorical system, which includes borderline personality disorder. The International Classification of Diseases, 11th Revision classification has five domain traits. Each of the Diagnostic and Statistical Manual of Mental Disorders personality disorder symptoms or behaviours from Structured Clinical Interview for Personality Disorder-II was reordered into the five domains independently by two assessors. The relationship between the two systems was examined by tabular and correlational analysis.

RESULTS

The findings showed that the symptoms of borderline personality disorder were associated with greater severity of personality disturbance in the International Classification of Diseases, 11th Revision classification (p < 0.0001) and were associated primarily with the Negative Affective, Dissocial and Disinhibited domains. There was only a weak association with the other two domains, Anankastia and Detachment.

CONCLUSION

The addition of a borderline pattern descriptor is likely to add little to the International Classification of Diseases, 11th Revision classification of personality disorder. Its features are well represented within the severity/domain structure, which allows for more fine-grained description of the personality features that constitute the borderline concept.

Social Causation, Social Selection, or Common Determinants? Examining Competing Explanations for the Link Between Young Adult Unemployment and Nicotine Dependence

INTRODUCTION

Unemployment has been related to smoking, yet the causal nature of the association is subject to continued debate. Social causation argues that unemployment triggers changes in smoking, whereas the social selection hypothesis proposes that pre-existing smoking behavior lowers the probability of maintaining employment. The present study tested these competing explanations while accounting for another alternative explanation-common liability.

METHODS

Data were from the Christchurch Health and Development Study, a longitudinal cohort followed from birth to age 35. Odds were generated for having nicotine dependence in models for social causation and being unemployed in models for social selection. These models were extended to include possible common liability factors during childhood (eg, novelty seeking) and young adulthood (eg, major depression).

RESULTS

In the model testing social causation, coefficients representing the impacts of unemployment on nicotine dependence remained statistically significant and robust (odds ratio [OR] = 1.55; 95% confidence interval [CI] = 1.20, 2.00), even after accounting for common determinant measures. In contrast, a reverse social selection model revealed that coefficients representing the impacts of nicotine dependence on unemployment substantially attenuated and became statistically nonsignificant as childhood factors were added (OR = 1.14; 95% CI = 0.90, 1.45).

CONCLUSIONS

Unemployment may serve as inroads to nicotine addiction among young adults, not the other way, even in the context of nicotine dependence, a more impaired form of smoking that may arguably hold higher potential to generate social selection processes. This social causation process cannot be completely attributable to common determinant factors.

IMPLICATIONS

It is critical to clarify whether unemployment triggers changes in smoking behaviors (ie, social causation) or vice versa (ie, social selection)-the answers to the question will lead to public health strategies with very different intervention targets to break the linkage. The current study findings favor social causation over social selection, regardless of gender, and support a needed shift in service profiles for unemployed young adults-from a narrow focus on job skills training to a more holistic approach that incorporates knowledge from addiction science in which unemployed young adults can find needed services to cope with job loss.

Sexual orientation and mental health over the life course in a birth cohort

BACKGROUND

Sexual minority individuals consistently report higher rates of mental disorder than heterosexuals. However, much of the research has methodological limitations related to the classification of sexuality, the use of cross-sectional data and problematic sampling procedures such as using convenience samples.

METHODS

We used longitudinal data from a birth cohort enrolled in the Christchurch Health and Development Study (n = 1040). Latent class analysis was used to classify participants sexuality based on self-report data of sexual behaviour, attraction, identity and fantasy, gathered over five assessments between the ages of 18 and 35 years. Mental health and substance use outcome data were gathered at four assessments between the ages of 21 and 35 years. Potential covariate variables were collected during childhood.

RESULTS

The latent class analysis identified four groups interpreted as: 'heterosexual' 82%, 'mostly heterosexual' 12.6%, 'bisexual' 3.5% and 'gay/lesbian' 1.9%. In the sexual minority groups, women outnumbered men by at least 2:1. Pooled rates for mental health disorders of depression, anxiety disorders, suicidal ideation, cannabis abuse and total disorders, after adjustment for childhood covariate variables, were significantly higher in the sexual minority groups (p < 0.01). The strength of association between sexuality group and mental health outcomes did not differ according to sex. Fluidity in sexuality reports appeared unrelated to risk of mental health outcomes.

CONCLUSIONS

Over the life course, membership of a sexual minority group is clearly associated with mental health problems of depression, anxiety and suicidal ideation regardless of the age when same-sex attraction, behaviour, identity or fantasy is expressed.

Attitudes towards cannabis and cannabis law change in a New Zealand birth cohort

AIMS

Personal cannabis use is common across New Zealand, and an upcoming referendum will enable the public to vote on whether this should be legalised. The present research aimed to examine the attitudes of midlife New Zealand adults on cannabis use and legalisation, and to identify potential predictors of those attitudes.

METHODS

At age 40, 899 participants drawn from the Christchurch Health and Development Study were interviewed about the perceived harmfulness of cannabis use, opinions on legalisation for recreational use and supply, and the use of cannabis for medicinal purposes. In addition, a range of potential predictors of legislative attitudes were examined.

RESULTS

We identified a wide range of attitudes across the cohort, however the majority tended to hold a neutral view. More than 80% of the cohort expressed support for medicinal cannabis, while 47.8% supported decriminalisation, and 26.8% expressed support for legalisation for recreational use. The strongest predictors of support for legalisation were prior use of cannabis and other drugs, while additional positive predictors included a history of depression, Māori ancestry, parental drug use, novelty seeking and higher educational attainment. Predictors of more negative attitudes were also identified, and included female gender and having dependent children.

CONCLUSIONS

These findings provide insight into cannabis-related views within the New Zealand context, and may help to predict voting behaviour during the 2020 Cannabis Referendum.

Genome-wide DNA methylation analysis of heavy cannabis exposure in a New Zealand longitudinal cohort

Cannabis use is of increasing public health interest globally. Here we examined the effect of heavy cannabis use, with and without tobacco, on genome-wide DNA methylation in a longitudinal birth cohort (Christchurch Health and Development Study, CHDS). A total of 48 heavy cannabis users were selected from the CHDS cohort, on the basis of their adult exposure to cannabis and tobacco, and DNA methylation assessed from whole blood samples, collected at approximately age 28. Methylation in heavy cannabis users was assessed, relative to non-users (n = 48 controls) via the Illumina Infinium® MethylationEPIC BeadChip. We found the most differentially methylated sites in cannabis with tobacco users were in the AHRR and F2RL3 genes, replicating previous studies on the effects of tobacco. Cannabis-only users had no evidence of differential methylation in these genes, or at any other loci at the epigenome-wide significance level (P < 10^-7). However, there were 521 sites differentially methylated at P < 0.001 which were enriched for genes involved in neuronal signalling (glutamatergic synapse and long-term potentiation) and cardiomyopathy. Further, the most differentially methylated loci were associated with genes with reported roles in brain function (e.g. TMEM190, MUC3L, CDC20 and SP9). We conclude that the effects of cannabis use on the mature human blood methylome differ from, and are less pronounced than, the effects of tobacco use, and that larger sample sizes are required to investigate this further.

Life-course trajectories of cannabis use: a latent class analysis of a New Zealand birth cohort

BACKGROUND AND AIMS

Little is known about how cannabis use over the life-course relates to harms in adulthood. The present study aimed to identify trajectories of cannabis use from adolescence to adulthood and examine both the predictors of these trajectories and adverse adult outcomes associated with those trajectories.

DESIGN

A latent trajectory analysis of a longitudinal birth cohort (from birth to age 35 years).

SETTING AND PARTICIPANTS

General community sample (n = 1065) from New Zealand.

MEASUREMENT

Annual frequency of cannabis use (ages 15-35 years); childhood family and individual characteristics (birth to age 16 years); measures of adult outcomes (substance use disorders, ages 30-35 years; mental health disorders, ages 30-35 years; socio-economic outcomes at age 35 years; social/family outcomes at age 35 years).

FINDINGS

A six-class solution was the best fit to the data. Individuals assigned to trajectories with higher levels of cannabis use were more likely to have experienced adverse childhood family and individual circumstances. Membership of trajectories with higher levels of use was associated with increased risk of adverse outcomes at ages 30-35 years. Adjustment of these associations for the childhood family and individual predictors largely did not reduce the magnitude of the associations.

CONCLUSIONS

In New Zealand, long-term frequent cannabis use, or transition to such use, appears to be robustly associated with diverse harms in adulthood.

Childhood predictors of adult adiposity: findings from a longitudinal study

AIMS

The increasing prevalence of overweight and obesity has become a key challenge for New Zealand. The purpose of the present study was to examine childhood risk factors for adult adiposity in a longitudinal birth cohort.

METHODS

Data were gathered from the Christchurch Health and Development Study (CHDS), a birth cohort of 1,265 children born in Christchurch in 1977. Associations were examined between socio-demographic background, perinatal factors, infant and child characteristics, family functioning/child maltreatment and adiposity at ages 30 and 35 years. Adiposity was assessed using body mass index scores.

RESULTS

At ages 30 and 35, approximately one-third of cohort members were overweight and one-fifth were obese. Generalised estimating equation models showed that statistically significant (p<.05) predictors of later adiposity and overweight/obesity were: male gender, being born into a single-parent family, having parents with larger body size, higher early infant growth, limited or no breastfeeding, lower levels of cognitive ability and exposure to severe sexual abuse.

CONCLUSIONS

Overweight and obesity was associated with social and family background, biological endowment, cognitive ability and childhood adversity factors. These findings may assist in the development of structured adiposity intervention programmes in conjunction with established community organisations specialising in child and family health.

Genome-wide association study identifies eight risk loci and implicates metabo-psychiatric origins for anorexia nervosa

Characterized primarily by a low body-mass index, anorexia nervosa is a complex and serious illness1, affecting 0.9-4% of women and 0.3% of men2-4, with twin-based heritability estimates of 50-60%5. Mortality rates are higher than those in other psychiatric disorders6, and outcomes are unacceptably poor7. Here we combine data from the Anorexia Nervosa Genetics Initiative (ANGI)8,9 and the Eating Disorders Working Group of the Psychiatric Genomics Consortium (PGC-ED) and conduct a genome-wide association study of 16,992 cases of anorexia nervosa and 55,525 controls, identifying eight significant loci. The genetic architecture of anorexia nervosa mirrors its clinical presentation, showing significant genetic correlations with psychiatric disorders, physical activity, and metabolic (including glycemic), lipid and anthropometric traits, independent of the effects of common variants associated with body-mass index. These results further encourage a reconceptualization of anorexia nervosa as a metabo-psychiatric disorder. Elucidating the metabolic component is a critical direction for future research, and paying attention to both psychiatric and metabolic components may be key to improving outcomes.

Altered grey matter volume, perfusion and white matter integrity in very low birthweight adults

This study examined the long-term effects of being born very-low-birth-weight (VLBW, <1500 g) on adult cerebral structural development using a multi-method neuroimaging approach. The New Zealand VLBW study cohort comprised 413 individuals born VLBW in 1986. Of the 338 who survived to discharge, 229 were assessed at age 27–29 years. Of these, 150 had a 3 T MRI scan alongside 50 healthy term-born controls. The VLBW group included 53/57 participants born <28 weeks gestation. MRI analyses included: a) structural MRI to assess grey matter (GM) volume and cortical thickness; b) arterial spin labelling (ASL) to quantify GM perfusion; and c) diffusion tensor imaging (DTI) to measure white matter (WM) integrity. Compared to controls, VLBW adults had smaller GM volumes within frontal, temporal, parietal and occipital cortices, bilateral cingulate gyri and left caudate, as well as greater GM volumes in frontal, temporal and occipital areas. Thinner cortex was observed within frontal, temporal and parietal cortices. VLBW adults also had less GM perfusion within limited temporal areas, bilateral hippocampi and thalami. Finally, lower fractional anisotropy (FA) and axial diffusivity (AD) within principal WM tracts was observed in VLBW subjects. Within the VLBW group, birthweight was positively correlated with GM volume and perfusion in cortical and subcortical regions, as well as FA and AD across numerous principal WM tracts. Between group differences within temporal cortices were evident across all imaging modalities, suggesting that the temporal lobe may be particularly susceptible to disruption in development following preterm birth. Overall, findings reveal enduring and pervasive effects of preterm birth on brain structural development, with individuals born at lower birthweights having greater long-term neuropathology.

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Very-low-birth-weight adults had smaller GM volumes and thinner cortex than controls.

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VLBW adults also showed regions of larger grey matter volumes and thicker cortex.

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Several small regions showed lower cerebral perfusion in VLBW adults than in controls.

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Diffusion tensor MRI suggested poorer WM integrity in VLBW adults than in controls.

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Within VLBW adults, all MRI measures showed positive associations with birthweight.

Childhood abuse and psychotic experiences in adulthood: findings from a 35-year longitudinal study

BACKGROUND

The extent to which exposure to childhood sexual and physical abuse increases the risk of psychotic experiences in adulthood is currently unclear.AimsTo examine the relationship between childhood sexual and physical abuse and psychotic experiences in adulthood taking into account potential confounding and time-dynamic covariate factors.

METHOD

Data were from a cohort of 1265 participants studied from birth to 35 years. At ages 18 and 21, cohort members were questioned about childhood sexual and physical abuse. At ages 30 and 35, they were questioned about psychotic experiences (symptoms of abnormal thought and perception). Generalised estimating equation models investigated covariation of the association between abuse exposure and psychotic experiences including potential confounding factors in childhood (socioeconomic disadvantage, adverse family functioning) and time-dynamic covariate factors (mental health, substance use and life stress).

RESULTS

Data were available for 962 participants; 6.3% had been exposed to severe sexual abuse and 6.4% to severe physical abuse in childhood. After adjustment for confounding and time-dynamic covariate factors, those exposed to severe sexual abuse had rates of abnormal thought and abnormal perception symptoms that were 2.25 and 4.08 times higher, respectively than the 'no exposure' group. There were no significant associations between exposure to severe physical abuse and psychotic experiences.

CONCLUSIONS

Findings indicate that exposure to severe childhood sexual (but not physical) abuse is independently associated with an increased risk of psychotic experiences in adulthood (particularly symptoms of abnormal perception) and this association could not be fully accounted for by confounding or time-dynamic covariate factors.Declaration of interestNone.

Metabolic Syndrome in Very Low Birth Weight Young Adults and Controls: The New Zealand 1986 VLBW Study

OBJECTIVE

To assess the physical well-being and components of the metabolic syndrome in a national cohort of very low birth weight (VLBW) young adults and same age controls.

STUDY DESIGN

The New Zealand VLBW Study cohort prospectively included all infants with birth weight <1500 g born in 1986, with 338 (82%) surviving to discharge home. Height and weight were measured at age 7-8 years. The VLBW cohort (n = 229; 71% alive) and term-born controls (n = 100) aged 27-29 years were clinically assessed in a single center over 2 days, including assessment for components of the metabolic syndrome.

RESULTS

Compared with controls, both male and female VLBW adults were significantly shorter (P < .001), but only females were lighter (P < .001) and had lower mean body mass index (P = .044), fat mass, and body fat percentage. Males, but not females, had significantly higher systolic blood pressure (P = .028), but there were no significant differences in other components of the metabolic syndrome. There was no difference in the prevalence of the metabolic syndrome in VLBW adults compared with controls (males, 22.2% vs 11.1%; P = .15: females, 12.8% vs 13.1%; P = .95). Examining the VLBW cohort with logistic regression, male sex, gestational age <28 weeks, Māori/Pacific Island ethnicity, and body mass index >90th percentile at age 7-8 years were significant predictors for the metabolic syndrome at age 27-29 years, with ORs of 2-4.

CONCLUSIONS

Systolic blood pressure in males was the only component of the metabolic syndrome that was significantly elevated in VLBW adults compared with controls. Extreme prematurity (<28 weeks) and body mass index >90th percentile at age 7-8 years were significant predictors of the metabolic syndrome at age 27-29 years.

TRIAL REGISTRATION

Registered at the Australian Clinical Trials Registry: ACTRN12612000995875.

Unrecognised and unmet physical health problems in a national cohort of very low birthweight young adults and controls

ABSTRACT INTRODUCTIONYoung adults are often reluctant to seek medical attention. Compared with full-term controls, very low birthweight (&lt;1500 g; VLBW) young adults may have more health problems. AIMTo assess the frequency of unrecognised or unmet physical health needs during a comprehensive health and welfare assessment of a national cohort of VLBW adults born in 1986 compared with full-term controls. METHODSThe VLBW cohort (n = 229; 71% of those alive) and controls (n = 100) aged 27–29 years were assessed in one University Hospital over 2 days. Physical health assessments included growth, respiratory function, blood pressure, echocardiogram, renal function, blood tests and an interview. Cranial MRI scans were performed on 150 VLBW adults and 50 controls. Significant unrecognised or unmet health needs were defined as including a body mass index (BMI) &gt;30 plus raised fasting insulin &gt;80 pmol/L; any two of moderate respiratory obstruction, or reduced diffusing capacity, or being a regular smoker; cardiovascular: hypertension or abnormal echocardiogram. RESULTSAmong the VLBW cohort and controls; 61% versus 73% (P &lt; 0.05) rated their overall health as very good or excellent. A general practitioner (GP) referral letter was sent for 44% VLBW adults and 38% controls, concerning metabolic problems in 20% and 17% respectively; respiratory problems in 12% and 4% (P &lt; 0.05) respectively; cardiovascular problems in 14% and 12% respectively; abnormal renal function in 7% in both groups; and anaemia in 3% and 5% respectively. DISCUSSIONUnrecognised or unmet health needs were frequent in both VLBW young adults and controls. Respiratory problems and hypertension were more frequent in the former. Continuity of care is important for VLBW adults who require a regular GP. GPs should routinely ask about gestation and birthweight and VLBW graduates should volunteer this information.

The Anorexia Nervosa Genetics Initiative (ANGI): Overview and methods

BACKGROUND

Genetic factors contribute to anorexia nervosa (AN); and the first genome-wide significant locus has been identified. We describe methods and procedures for the Anorexia Nervosa Genetics Initiative (ANGI), an international collaboration designed to rapidly recruit 13,000 individuals with AN and ancestrally matched controls. We present sample characteristics and the utility of an online eating disorder diagnostic questionnaire suitable for large-scale genetic and population research.

METHODS

ANGI recruited from the United States (US), Australia/New Zealand (ANZ), Sweden (SE), and Denmark (DK). Recruitment was via national registers (SE, DK); treatment centers (US, ANZ, SE, DK); and social and traditional media (US, ANZ, SE). All cases had a lifetime AN diagnosis based on DSM-IV or ICD-10 criteria (excluding amenorrhea). Recruited controls had no lifetime history of disordered eating behaviors. To assess the positive and negative predictive validity of the online eating disorder questionnaire (ED100K-v1), 109 women also completed the Structured Clinical Interview for DSM-IV (SCID), Module H.

RESULTS

Blood samples and clinical information were collected from 13,363 individuals with lifetime AN and from controls. Online diagnostic phenotyping was effective and efficient; the validity of the questionnaire was acceptable.

CONCLUSIONS

Our multi-pronged recruitment approach was highly effective for rapid recruitment and can be used as a model for efforts by other groups. High online presence of individuals with AN rendered the Internet/social media a remarkably effective recruitment tool in some countries. ANGI has substantially augmented Psychiatric Genomics Consortium AN sample collection. ANGI is a registered clinical trial: clinicaltrials.govNCT01916538; https://clinicaltrials.gov/ct2/show/NCT01916538?cond=Anorexia+Nervosa&draw=1&rank=3.

Adverse adult consequences of different alcohol use patterns in adolescence: an integrative analysis of data to age 30 years from four Australasian cohorts

BACKGROUND AND AIMS

Studies have linked adolescent alcohol use with adverse consequences in adulthood, yet it is unclear how strong the associations are and to what extent they may be due to confounding. Our aim was to estimate the strength of association between different patterns of adolescent drinking and longer-term psychosocial harms taking into account individual, family and peer factors.

DESIGN

Participant-level data were integrated from four long-running longitudinal studies: Australian Temperament Project, Christchurch Health and Development Study, Mater Hospital and University of Queensland Study of Pregnancy and Victorian Adolescent Health Cohort Study.

SETTING

Australia and New Zealand.

PARTICIPANTS

Participants were assessed on multiple occasions between ages 13 and 30 years (from 1991 to 2012). Number of participants varied (up to n = 9453) by analysis.

MEASUREMENTS

Three patterns of alcohol use (frequent, heavy episodic and problem drinking) were assessed prior to age 17. Thirty outcomes were assessed to age 30 spanning substance use and related problems, antisocial behaviour, sexual risk-taking, accidents, socio-economic functioning, mental health and partner relationships.

FINDINGS

After covariate adjustment, weekly drinking prior to age 17 was associated with a two- to threefold increase in the odds of binge drinking [odds ratio (OR) = 2.14; 95% confidence interval (CI) = 1.57-2.90], drink driving (OR = 2.78; 95% CI = 1.84-4.19), alcohol-related problems (OR = 3.04; 95% CI = 1.90-4.84) and alcohol dependence (OR = 3.30; 95% CI = 1.69-6.47) in adulthood. Frequency of drinking accounted for a greater proportion of the rate of most adverse outcomes than the other measures of alcohol use. Associations between frequent, heavy episodic and problem drinking in adolescence and most non-alcohol outcomes were largely explained by shared risk factors for adolescent alcohol use and poor psychosocial functioning.

CONCLUSIONS

Frequency of adolescent drinking predicts substance use problems in adulthood as much as, and possibly more than, heavy episodic and problem drinking independent of individual, family and peer predictors of those outcomes.

Childhood predictors of adult adiposity: findings from a longitudinal study

AIMS

The increasing prevalence of overweight and obesity has become a key challenge for New Zealand. The purpose of the present study was to examine childhood risk factors for adult adiposity in a longitudinal birth cohort.

METHODS

Data were gathered from the Christchurch Health and Development Study (CHDS), a birth cohort of 1,265 children born in Christchurch in 1977. Associations were examined between socio-demographic background, perinatal factors, infant and child characteristics, family functioning/child maltreatment and adiposity at ages 30 and 35 years. Adiposity was assessed using body mass index scores.

RESULTS

At ages 30 and 35, approximately one-third of cohort members were overweight and one-fifth were obese. Generalised estimating equation models showed that statistically significant (p<.05) predictors of later adiposity and overweight/obesity were: male gender, being born into a single-parent family, having parents with larger body size, higher early infant growth, limited or no breastfeeding, lower levels of cognitive ability and exposure to severe sexual abuse.

CONCLUSIONS

Overweight and obesity was associated with social and family background, biological endowment, cognitive ability and childhood adversity factors. These findings may assist in the development of structured adiposity intervention programmes in conjunction with established community organisations specialising in child and family health.

New Insights into Cardiac and Vascular Natriuretic Peptides: Findings from Young Adults Born with Very Low Birth Weight

BACKGROUND

In community studies, plasma B-type natriuretic peptide (BNP) is positively associated with cardiovascular disorders. Those born with very low birth weight (VLBW) have increased risk of metabolic and vascular disorders in later life, but plasma concentrations of natriuretic peptides have not been studied. The objectives here were to evaluate BNP and C-type natriuretic peptide (CNP)—a putative marker of vascular risk—in young adults born with VLBW.

METHODS

In all, 220 VLBW cases and 97 matched controls were studied 28 years after birth during a 2-day period at 1 research center. Aminoterminal (NT) products (NTproBNP, NTproCNP) and a range of conventional vascular risk factors including echocardiographic indices were measured along with genetic polymorphisms known to increase plasma NTproBNP.

RESULTS

VLBW individuals were smaller, had smaller hearts, reduced stroke volume and endothelial function, and higher systolic blood pressure and arterial elastance. Of the many humoral vascular and metabolic risk factors measured, including NTproBNP, only plasma NTproCNP (higher in VLBW individuals) differed significantly. Across all individuals, associations of NTproCNP with each of 7 conventional risk factors, as well as with arterial elastance, were positive, whereas associations of NTproBNP with risk were all inverse. In multivariate analysis, the genetic variant rs198358 was independently associated with NTproBNP.

CONCLUSIONS

In young adults at increased risk of cardiovascular disease, higher NTproCNP likely reflects a compensatory vascular response to vascular stress, whereas the negative link with NTproBNP likely reflects beneficial genetic mutations. The ratio of NTproBNP to NTproCNP may provide a novel index of ideal cardiovascular health.

Vision in former very low birthweight young adults with and without retinopathy of prematurity compared with term born controls: the NZ 1986 VLBW follow-up study

Objective

There are few data on visual outcomes in adulthood of former very low birthweight (VLBW; <1500 g) infants. We aimed to assess vision at 27–29 years in a national cohort of VLBW infants born in 1986 and assessed for retinopathy of prematurity (ROP) when no treatment was available, compared with term born controls.

Methods

The cohort and controls attended a 2-day assessment in Christchurch as part of a larger study. Visual assessment included glasses prescription measured by focimeter, logarithm of the minimum angle of resolution (logMAR) distance visual acuity (VA), contrast sensitivity, autorefraction, retinal photographs and a questionnaire on vision-related everyday activities. Rates of reduced VA and myopia in the VLBW cohort at 27–29 were compared with the results of vision testing at 7–8 years.

Results

250 VLBW adults (77% those alive) gave study consent and 229 (45 with a history of ROP) were assessed in Christchurch, plus 100 term born controls. VLBW adults with ROP had reduced VA compared with no ROP and controls (mean logMAR score (SD); 0.003 (0.19), –0.021 (0.16), –0.078 (0.09), P=0.001). There were no differences in myopia (>2 D) between the groups but high myopia (>5 D) was confined to those with ROP. VLBW adults with ROP drove a car less often and had higher difficulties with everyday activities scores due to eyesight. Between 7–8 and 27–29 years rates of reduced VA were stable but myopia increased.

Conclusion

Former VLBW young adults with ROP have ongoing problems with vision affecting daily living and should continue in regular ophthalmological review.

Trial registration number

ACTRN12612000995875, Pre-results .

The role of novelty seeking as a predictor of substance use disorder outcomes in early adulthood

BACKGROUND AND AIMS

There has been a great deal of evidence showing that high novelty seeking (NS) is a risk factor for the development of substance use disorders (SUDs). However, the possible causal role of NS in SUDs is unconfirmed. The aim of this study was to examine the associations between NS at age 16 and SUDs from ages 18 to 35 years, net of a series of covariate factors.

DESIGN

Longitudinal study of a birth cohort.

SETTING

Christchurch, New Zealand.

PARTICIPANTS

General community sample with sample sizes ranging from n = 1011 (age 21) to n = 962 (age 35).

MEASUREMENTS

The Composite International Diagnostic Interview was used to derive DSM-IV diagnoses of alcohol, nicotine, cannabis and other illicit SUDs at four time intervals from ages 18 to 35. NS was measured at age 16 using the Tridimensional Personality Questionnaire.

FINDINGS

An increase in NS was associated with increases in the prevalence of all four SUDs at age 18-35. Following adjustment for a broad range of covariate factors, estimated effect sizes (odds ratios) were reducing in magnitude, but remained moderate to large. Adjusted odds ratios of SUDs for the highest NS quartile compared to with the lowest were 2.0 [95% confidence interval (CI) = 1.5, 2.7] for alcohol; 1.8 (95% CI = 1.3, 2.7) for nicotine; 3.6 (95% CI = 2.4, 5.6) for cannabis and 5.1 (95% CI = 2.9, 9.2) for other illicit substances.

CONCLUSIONS

The association between high novelty seeking and substance use disorders is not explained by common underlying individual factors and environmental exposures. This is consistent with the view that novelty seeking may play a causal role in the development of substance use disorders.

The Niemann-Pick C1 gene interacts with a high-fat diet to promote weight gain through differential regulation of central energy metabolism pathways

A genome-wide association study (GWAS) reported that common variation in the human Niemann-Pick C1 gene (NPC1) is associated with morbid adult obesity. This study was confirmed using our BALB/cJ Npc1 mouse model, whereby heterozygous mice (Npc1^+/- ) with decreased gene dosage were susceptible to weight gain when fed a high-fat diet (HFD) compared with homozygous normal mice (Npc1^+/+ ) fed the same diet. The objective for our current study was to validate this Npc1 gene-diet interaction using statistical modeling with fitted growth trajectories, conduct body weight analyses for different measures, and define the physiological basis responsible for weight gain. Metabolic phenotype analysis indicated no significant difference between Npc1^+/+ and Npc1^+/- mice fed a HFD for food and water intake, oxygen consumption, carbon dioxide production, locomotor activity, adaptive thermogenesis, and intestinal lipid absorption. However, the livers from Npc1^+/- mice had significantly increased amounts of mature sterol regulatory element-binding protein-1 (SREBP-1) and increased expression of SREBP-1 target genes that regulate glycolysis and lipogenesis with an accumulation of triacylglycerol and cholesterol. Moreover, white adipose tissue from Npc1^+/- mice had significantly decreased amounts of phosphorylated hormone-sensitive lipase with decreased triacylglycerol lipolysis. Consistent with these results, cellular energy metabolism studies indicated that Npc1^+/- fibroblasts had significantly increased glycolysis and lipogenesis, in addition to significantly decreased substrate (glucose and endogenous fatty acid) oxidative metabolism with an accumulation of triacylglycerol and cholesterol. In conclusion, these studies demonstrate that the Npc1 gene interacts with a HFD to promote weight gain through differential regulation of central energy metabolism pathways.

The role of peri-traumatic stress and disruption distress in predicting symptoms of major depression following exposure to a natural disaster

OBJECTIVE

Few studies have examined the contribution of specific disaster-related experiences to symptoms of depression. The aims of this study were to do this by examining the roles of peri-traumatic stress and distress due to lingering disaster-related disruption in explaining linkages between disaster exposure and major depressive disorder symptoms among a cohort exposed to the 2010-2011 Canterbury (New Zealand) earthquakes.

METHODS

Structural equation models were fitted to data obtained from the Christchurch Health and Development Study at age 35 ( n = 495), 20-24 months following the onset of the disaster. Measures included earthquake exposure, peri-traumatic stress, disruption distress and symptoms of major depressive disorder.

RESULTS

The associations between earthquake exposure and major depression were explained largely by the experience of peri-traumatic stress during the earthquakes (β = 0.180, p < 0.01) and not by disruption distress following the earthquakes (β = 0.048, p = 0.47).

CONCLUSION

The results suggest that peri-traumatic stress has been under-recognised as a predictor of major depressive disorder.

Microsatellite polymorphisms associated with human behavioural and psychological phenotypes including a gene-environment interaction

Background

The genetic and environmental influences on human personality and behaviour are a complex matter of ongoing debate. Accumulating evidence indicates that short tandem repeats (STRs) in regulatory regions are good candidates to explain heritability not accessed by genome-wide association studies.

Methods

We tested for associations between the genotypes of four selected repeats and 18 traits relating to personality, behaviour, cognitive ability and mental health in a well-studied longitudinal birth cohort (n = 458-589) using one way analysis of variance. The repeats were a highly conserved poly-AC microsatellite in the upstream promoter region of the T-box brain 1 (TBR1) gene and three previously studied STRs in the activating enhancer-binding protein 2-beta (AP2-β) and androgen receptor (AR) genes. Where significance was found we used multiple regression to assess the influence of confounding factors.

Results

Carriers of the shorter, most common, allele of the AR gene’s GGN microsatellite polymorphism had fewer anxiety-related symptoms, which was consistent with previous studies, but in our study this was not significant following Bonferroni correction. No associations with two repeats in the AP2-β gene withstood this correction. A novel finding was that carriers of the minor allele of the TBR1 AC microsatellite were at higher risk of conduct problems in childhood at age 7-9 (p = 0.0007, which did pass Bonferroni correction). Including maternal smoking during pregnancy (MSDP) in models controlling for potentially confounding influences showed that an interaction between TBR1 genotype and MSDP was a significant predictor of conduct problems in childhood and adolescence (p < 0.001), and of self-reported criminal behaviour up to age 25 years (p ≤ 0.02). This interaction remained significant after controlling for possible confounders including maternal age at birth, socio-economic status and education, and offspring birth weight.

Conclusions

The potential functional importance of the TBR1 gene’s promoter microsatellite deserves further investigation. Our results suggest that it participates in a gene-environment interaction with MDSP and antisocial behaviour. However, previous evidence that mothers who smoke during pregnancy carry genes for antisocial behaviour suggests that epistasis may influence the interaction.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0374-y) contains supplementary material, which is available to authorized users.

Exposure to parental separation in childhood and later parenting quality as an adult: evidence from a 30-year longitudinal study

BACKGROUND

Previous research has documented that exposure to parental separation/divorce during childhood can be associated with long-term consequences into adulthood. This study sought to extend this literature by examining associations between childhood exposure to parental separation/divorce and later parenting behavior as an adult in a New Zealand birth cohort.

METHODS

Data were drawn from the Christchurch Health and Development Study (CHDS), a longitudinal study of a birth cohort of 1,265 children born in 1977 in Christchurch, New Zealand. Information about exposure to parental separation and divorce was gathered annually from birth to 15 years. At the 30-year follow-up, all cohort members who had become parents (biological or nonbiological) were assessed on several parenting dimensions (sensitivity, warmth, overreactivity, inconsistency, quality of child management, and physical punishment).

RESULTS

The analyses showed that exposure to more frequent parental separation in childhood and adolescence was associated with lower levels of parental sensitivity and warmth, greater overreactivity, and an increased use of physical punishment as a parent, after controlling for a wide range of family socioeconomic and psychosocial factors, and individual child characteristics.

CONCLUSIONS

The findings suggest that as exposure to parental separation increases, so does the likelihood of experiencing multiple developmental challenges in childhood and adolescence. As an adult, these life-course experiences can have small but significant associations with the quality of parenting behavior.

Enduring mental health: Prevalence and prediction

We review epidemiological evidence indicating that most people will develop a diagnosable mental disorder, suggesting that only a minority experience enduring mental health. This minority has received little empirical study, leaving the prevalence and predictors of enduring mental health unknown. We turn to the population-representative Dunedin cohort, followed from birth to midlife, to compare people never-diagnosed with mental disorder (N = 171; 17% prevalence) to those diagnosed at 1–2 study waves, the cohort mode (N = 409). Surprisingly, compared to this modal group, never-diagnosed Study members were not born into unusually well-to-do families, nor did their enduring mental health follow markedly sound physical health, or unusually high intelligence. Instead, they tended to have an advantageous temperament/personality style, and negligible family history of mental disorder. As adults, they report superior educational and occupational attainment, greater life satisfaction, and higher-quality relationships. Our findings draw attention to “enduring mental health” as a revealing psychological phenotype and suggest it deserves further study.

This study reviews evidence indicating that the experience of a diagnosable mental disorder at some point during the life course is the norm, not the exception. Our results suggest that the comparatively few individuals who manage to avoid such conditions owe their extraordinary mental health to an advantageous personality style and lack of family history of disorder, but not to childhood socioeconomic privilege, superior health, or high intelligence.

Ethnicity and Bias in Police Contact Statistics

The relationships between ethnicity, self/parentally reported offending and rates of police contact were examined in a birth cohort of Christchurch (New Zealand) born children studied to the age of 15 years. This analysis suggested that whilst children of Maori/Pacific Island descent offended at a significantly higher rate than European (Pakeha) children, there were clear differences in the magnitude of ethnic differentials in offending depending on the way in which offending was measured. On the basis of self/parentally reported offending, children of Maori/Pacific Island descent offended at about 1.7 times the rate of Pakeha children. However, on the basis of police contact statistics these children were 2.9 times more likely to come to police attention than Pakeha children. These differences between self/parentally reported offending rates and rates of police contact could not be explained by the fact that Maori/Pacific Island children offended more often or committed different types of offences than Pakeha children. Logistic modelling of the data suggested that children of Maori/Pacific Island descent were in the region of 2.4 times more likely to come to official police attention than Pakeha children with an identical self/parental reported history of offending. These results are generally consistent with the hypothesis that official police contact statistics contain a bias which exaggerates the differences in the rate of offending by children of Maori/Pacific Island descent and Pakeha children.

Ethnicity and Criminal Convictions: Results of a 21-year Longitudinal Study

This study explores possible ethnic bias in rates of officially recorded convictions among a birth cohort of New Zealand young people studied to age 21 years. Data were gathered as part of the Christchurch Health and Development Study. In this project a cohort of 1265 children born in Christchurch in 1977 have been studied from birth to age 21 years. The measures collected included: officially recorded convictions (17–21 years), self-reported ethnicity (21 years), self-reported offending (17–21 years), family socioeconomic status, leaving school without qualifications, and gender. Young Maori had rates of conviction that were between 4.1–5.9 times higher than for non-Maori. Much of this association was explained by the fact that Maori also reported higher rates of offending. However, even after statistical control for self-reported offending and individual characteristics (gender, socioeconomic status and educational qualifications) Maori still had rates of conviction that were 1.6–1.8 times higher than non-Maori These results suggest the presence of a small bias in the arrest/conviction process which leads to Maori offenders having higher rates of conviction than non-Maori offenders with similar offending history and socioeconomic background.

Ethnicity, Social Backgroud and Young Offending: A 14-Year Longitudinal Study

The relationship between ethnicity and rates of violent, property and other offences based on self-report and parental report data was studied for a birth cohort of Christchurch born children. The results show that on the basis of report data, children of Maori ethnicity had significantly (p<.05) higher rates of offending than children of Pakeha (European) ethnicity with these rates being from 1.45 to 2.25 times higher than for Pakeha children. However, after adjustment for a series of social and contextual factors including maternal age, maternal educational levels, family socio-economic status, family living standards and early childhood environment factors, these associations reduced so that children of Maori or Pacific Island ethnicity had risks of offending which ranged from 1.08 to 1.55 times higher than children of Pakeha ethnicity. In four of the five comparisons made there was no significant relationship between ethnicity and offending after adjustment for these social and contextual factors. The implications of these findings for the interpretation of ethnic differences in rates of offending are examined with particular attention being given to labelling, socio-economic and cultural explanations of these differences.

Life-stress and reactivity by gender in a longitudinal birth cohort at 30 and 35 years

PURPOSE

Previous literature has shown gender differences in reactivity to stressful life events. However, it is unclear whether gender differences in stress reactivity are consistent across a series of life event domains among longitudinal adult sample populations.

METHODS

Data were gathered from the Christchurch Health and Development Study (CHDS). The CHDS is a longitudinal birth cohort of 1265 children born in 1977 in Christchurch, New Zealand. Cohort members were questioned on their experience of, and distress from, a series of life event domains (interpersonal problems; victimization; illness/death; pregnancy/parenthood; employment/finance problems) spanning two age-periods 25-30 years (data collected in 2007) and 30-35 years (data collected in 2012). The data were pooled across observations and analyzed using population-averaged repeated-measures regression methods.

RESULTS

Overall, men and women reported experiencing similar numbers of life events for each domain. However, men reported more victimization and more employment/financial problems; women reported more illness/death events. Women reported experiencing more distress per life event for the domains of interpersonal problems, illness/death and pregnancy/parenthood. Men and women reported similar distress per life event for the victimization and employment/finance domains. The results were robust to control for: child and adolescent factors (childhood abuse exposure; adolescent personality; mental health) and adult factors (mental health; self-esteem).

CONCLUSION

These findings are consistent with a growing body of evidence indicating that some life events including interpersonal problems, illness/death and pregnancy/parenthood may be intrinsically more distressing for women. Detection of life event distress is important to aid in the prevention of mental/physical health problems.

Cognitive Development Trajectories of Very Preterm and Typically Developing Children

Cognitive impairment is common among children born very preterm (VPT), yet little is known about how this risk changes over time. To examine this issue, a regional cohort of 110 VPT (≤ 32 weeks gestation) and 113 full-term (FT) born children was prospectively assessed at ages 4, 6, 9, and 12 years using the Wechsler Preschool and Primary Scale of Intelligence-Revised and then Wechsler Intelligence Scale for Children, 4th ed. At all ages, VPT children obtained lower scores than their FT born peers (p < .001). Growth curve modeling revealed stable cognitive trajectories across both groups. Neonatal white matter abnormalities and family socioeconomic adversity additively predicted cognitive risk. Despite some intraindividual variability, cognitive functioning of typically developing and high-risk VPT children was stable and influenced by early neurological development and family rearing context.

The accuracy of adult recall for early mild traumatic brain injury

BACKGROUND

Childhood mild traumatic brain injury (mTBI) has been associated with negative adult outcomes. Effective interventions require identification of the injury event. There is currently little information regarding the accuracy of adult recall of childhood mTBI.

METHOD

Prospectively collected information from a large birth cohort was used to examine adult recall accuracy at age 25 for 161 childhood mTBI events occurring before age 10.

RESULTS

At age 25 cohort members recalled 11 outpatient injuries and 16 inpatient injuries. Recall accuracy increased with age. Logistic regression analysis distinguished between respondents who reported and did not report a childhood mTBI event correctly classifying 84.5% of cases. Age at injury, injury severity and loss of consciousness (LoC) made a unique statistically significant contribution to the model.

CONCLUSIONS

Most childhood mTBI events are not recalled in adulthood. Age at injury, injury severity and LoC significantly increase likelihood of recall and should be used in measures that evaluate whether injury has occurred. Implications for rehabilitation Traumatic brain injury occurs frequently and often results in ongoing deficits in attention, concentration, executive function and later mental health problems. Identification of a history of traumatic brain injury is essential to ensure that appropriate rehabilitative input is provided. Rehabilitation professionals need to be aware that mental health problems may be secondary to a prior traumatic brain injury. It is important for rehabilitation professionals elicit an accurate history of traumatic brain injury to ensure that their treatment plans are tailored to the needs of this group.

Examination of a possible J-shaped relationship between alcohol consumption and internalizing disorders in a longitudinal birth cohort

BACKGROUND

Many studies have reported a J-shaped relationship between alcohol use and affective or anxiety symptoms, with abstainers experiencing more severe symptoms than moderate drinkers. It is less clear whether this relationship is also present for the risk of syndromal internalizing disorders such as depression or anxiety disorders.

METHODS

A New Zealand longitudinal birth cohort study (n=1265). Participants were interviewed at ages 18, 21, 25, 30 and 35 years. Alcohol consumption level and the presence of internalizing disorders (major depression; anxiety disorder) for the previous 12 months were determined at each time point. The association between drinking status and major depression and anxiety disorders at ages 18, 21, 25, 30 and 35 years was investigated via Generalized Estimating Equation modelling.

RESULTS

There was little evidence of a statistically significant (p<.05) association between alcohol consumption levels and either: (a) major depression; or (b) anxiety disorder; across the period 18-35 years. Inspection of the annual data showed considerable fluctuation in rates of disorder across alcohol consumption categories.

CONCLUSION

In young adults there was little evidence of a J-shaped relationship between alcohol use and both major depression and anxiety disorder.

Adolescent depression, adult mental health and psychosocial outcomes at 30 and 35 years

BACKGROUND

There is limited information on long-term outcomes of adolescent depression. This study examines the associations between severity of depression in adolescence and a broad array of adult functional outcomes.

METHOD

Data were gathered as part of the Christchurch Health and Development Study, a 35-year longitudinal study of a birth cohort of 1265 children born in Christchurch, New Zealand in 1977. Severity of depression at age 14-16 years was classified into three levels according to DSM symptom criteria for major depression (no depression/sub-threshold symptoms/major depression). This classification was related to adult functional outcomes assessed at ages 30 and 35 years using a generalized estimating equation modeling approach. Outcome measures spanned domains of mental disorder, education/economic circumstances, family circumstances and partner relationships.

RESULTS

There were modest but statistically significant bivariate associations between adolescent depression severity and most outcomes. After covariate adjustment there remained weak but significant (p < 0.05) associations with rates of major depression, anxiety disorder, illicit substance abuse/dependence, any mental health problem and intimate partner violence (IPV) victimization. Estimates of attributable risk for these outcomes ranged from 3.8% to 7.8%. For two outcomes there were significant (p < 0.006) gender interactions such that depression severity was significantly related to increased rates of unplanned pregnancy and IPV victimization for females but not for males.

CONCLUSIONS

The findings reinforce the importance of the individual/family context in which adolescent depression occurs. When contextual factors and probable maturational effects are taken into account the direct effects of adolescent depression on functioning in mature adulthood appear to be very modest.