Exploring the relationships between pathogen-specific prenatal infections requiring inpatient admission and domains of offspring behaviour at age 5.

BACKGROUND: Research exploring the relationship between prenatal infection and child behavioural outcomes would benefit from further studies utilising full-population samples with the scale to investigate specific infections and to employ robust designs. We tested the association among several common infections requiring inpatient admission during and after pregnancy with a range of childhood behavioural outcomes, to determine whether any negative impact was specific to the period of foetal development. METHODS: The sample included all mother-offspring pairs from the Australian state of New South Wales (NSW) for whom the child commenced their first year of full-time schooling in 2009 (~age 5 years; n = 77,302 offspring), with records linked across four health administrative data sets including the NSW perinatal data collection (PDC), the NSW admitted patient data collection (APDC) and the NSW component of the 2009 Australian Early Development Census (AEDC). Multivariable linear regression was used to test associations between a number of infections requiring inpatient admission during and after pregnancy with a range of teacher assessed behavioural outcomes. RESULTS: Associations specific to the prenatal period were only found for streptococcus A although this would need to be reproduced in external samples given the low prevalence. Otherwise, 12 out of 15 selected infections either showed no association prenatally or also demonstrated associations in the 12 months after pregnancy. For example, prenatal hepatitis C, influenza and urinary E. coli infections were associated with lower scores of several domains of childhood behaviour, but even stronger associations were found when these same maternal infections occurred after pregnancy. CONCLUSIONS: The prenatal infections we tested appeared not to impact childhood behaviour by altering foetal neurodevelopment. Rather, the strong associations we found among infections occurring during and after pregnancy point to either residual socioeconomic/lifestyle factors or a shared familial/genetic liability between infections and behavioural problems.

Low-moderate prenatal alcohol exposure and offspring attention-deficit hyperactivity disorder (ADHD): systematic review and meta-analysis.

PURPOSE: To evaluate the available evidence on the association between low-to-moderate prenatal alcohol exposure (PAE) and the development of attention-deficit hyperactivity disorder (ADHD) symptoms in the offspring. METHODS: We systematically reviewed and meta-analysed studies reporting an association between low and/or moderate PAE and offspring ADHD symptoms (attention and/or hyperactivity). Systematic searches were performed in EMBASE, Pubmed, Medline, and PsycINFO and reviewed from selected references. Random effects modelling was conducted to pool adjusted odds ratios (OR) in different alcohol consumption levels (≤ 20 g/week, ≤ 50 g/week, and ≤ 70 g/week). Stratified analysis by sex per alcohol level was conducted to investigate the difference on OR and the magnitude between-study heterogeneity. RESULTS: Ten studies were included in the systematic review and six in the meta-analysis. Eight studies found no association and two studies suggested an apparent protective effect of low PAE in hyperactivity/inattention symptoms in boys. These results were confirmed by the meta-analysis showing no association between ≤ 20 g/week [OR 1.01 (0.68-1.49)], ≤ 50 g/week [OR 0.94 (0.85-1.03)] and ≤ 70 g/week [OR 0.94 (0.86-1.02)] and ADHD symptoms, with no evidence of publication bias. Stratified analysis by sex for a PAE ≤ 50 g/week exposed less risk of ADHD symptoms in boys compared to girls [OR 0.89 (0.83-0.96)]. CONCLUSIONS: We found no increased risk of ADHD symptoms in offspring born to mothers who drank alcohol up to 70 g/week.

Is low BMI associated with specific drug use among injecting drug users?

Body mass index (BMI) of a sample of people who regularly inject drugs (N = 781) was examined to gauge the impact of specific types of drug use. Cross-sectional interviews were undertaken in 2010 as part of a national monitoring program funded by the Australian Government. Latent class analysis identified three groups of drug users, with heroin users at 3.4 times the risk of being underweight compared with amphetamine users, and amphetamine users were at almost twice the odds of being obese compared with lower level morphine users. Nutrition should play a part in harm minimization.

Development and validation of a machine learning-based tool to predict autism among children.

Autism is a lifelong condition for which intervention must occur as early as possible to improve social functioning. Thus, there is great interest in improving our ability to diagnose autism as early as possible. We take a novel approach to this challenge by combining machine learning with maternal and infant health administrative data to construct a prediction model capable of predicting autism disorder (defined as ICD10 84.0) in the general population. The sample included all mother-offspring pairs from the Australian state of New South Wales (NSW) between January 2003 and December 2005 (n = 262,650 offspring), linked across three health administrative data sets including the NSW perinatal data collection (PDC); the NSW admitted patient data collection (APDC) and the NSW mental health ambulatory data collection (MHADC). Our most successful model was able to predict autism disorder with an area under the receiver operating curve of 0.73, with the strongest risk factors for diagnoses found to include offspring gender, maternal age at birth, delivery analgesia, maternal prenatal tobacco disorders, and low 5-min APGAR score. Our findings indicate that the combination of machine learning and routinely collected admin data, with further refinement and increased accuracy than achieved by us, may play a role in the early detection of autism disorders.

The association between lower birth weight and comorbid generalised anxiety and major depressive disorder.

OBJECTIVE: Studies testing the association between birth weight and depression or anxiety have found inconsistent results and there has been a lack of research on the possible relationship between birth weight and comorbid anxiety and depression. We tested for an association between lower birth weight and major depression, generalised anxiety and comorbid generalised anxiety and major depression. METHOD: Data was taken from 2113 mothers and their offspring participating in the Mater University Study of Pregnancy (MUSP) birth cohort. Generalised anxiety, major depression and comorbid generalised anxiety and major depression at 21 years were tested for associations with birth weight using multinomial logistic regression. RESULTS: Lower birth weight was found to predict comorbid generalised anxiety and major depression, but did not predict either generalised anxiety or major depression. LIMITATIONS: We were unable to specify comorbidity by the primary disorder, or by the severity or recurrence of the depression. CONCLUSION: Previous associations found between birth weight and mental health may reflect a specific link between lower birth weight and comorbid generalised anxiety and major depressive disorders. As neither disorder individually was associated with lower birth weight, this may suggest that this developmental origin represents a unique risk pathway to comorbidity not shared with either discrete disorder.

The role of sleep disturbance in the relationship between post-traumatic stress disorder and suicidal ideation.

We tested if the risk of suicidal ideation in individuals with PTSD symptoms was dependent on comorbid sleep disturbance. Our cross-sectional sample included 2465 participants with complete data from the 21 year follow-up of the Mater University Study of Pregnancy (MUSP), a birth cohort study of young Australians. Using structural equation modelling with indirect pathways we found that 12 month PTSD symptoms did not directly predict suicidal ideation at 21 when adjusting for major depression symptoms, polyvictimization and gender. However, PTSD symptoms had an indirect effect on suicidal ideation via past-month sleep disturbance. Our results suggest that increased suicidal ideation in those with PTSD may result from the fact that PTSD sufferers often exhibit other comorbid psychiatric conditions which are themselves known to predict suicidal behaviours. Sleep disturbance may be targeted in those who experience PTSD to help prevent suicidal ideation.

Pre-trauma verbal ability at five years of age and the risk of post-traumatic stress disorder in adult males and females.

Previous studies have shown that high cognitive ability, measured in childhood and prior to the experience of traumatic events, is protective of PTSD development. Our aim was to test if the association between pre-trauma verbal ability ascertained at 5 years with DSM-IV lifetime post-traumatic stress disorder (PTSD) at 21 years was subject to effect modification by gender, trauma type or prior behaviour problems. Using a prospective birth cohort of young Australians, we found that both trauma type and behaviour problems did not change the association between cognitive ability and PTSD. During multivariate analysis, testing for the interactive effect of gender revealed that verbal ability was linearly and inversely associated with PTSD in females only, with those in the lowest verbal ability quintile having strongly increased odds of PTSD (OR=3.89: 95% CI; 1.50, 10.10) compared with those in the highest quintile. A graph of the interaction revealed lower verbal ability placed females, but not males, at an increased risk of PTSD. Our results indicate that lower verbal ability in early childhood is a vulnerability factor for PTSD in females but not in males, and may constitute a gender-specific risk factor responsible for part of the increased risk of PTSD found in females compared with males.

The association between birth weight and anxiety disorders in young adults.

Recent evidence has linked birth weight to later behaviour/mental disorders, yet studies have hitherto neglected to investigate the relationship between birth weight and adult anxiety disorders. Prospectively collected data from 2210 mother/offspring pairs of the Mater University Study of Pregnancy (MUSP) birth cohort was used to test for associations between birth weight z-score and four major groupings of DSM-IV anxiety disorders. Birth weight z-score was linearly and inversely associated with lifetime diagnosis of post-traumatic stress disorders at 21 years, with those falling within the smallest birth weight quintile group at almost two-fold increased odds (OR=1.96, 95% CI: 1.10, 3.52) of being diagnosed with the disorder compared to those falling within the largest group. The association remained when subsequent analysis restricted the sample to those exposed to trauma. This is the first study in which birth weight has been found to be associated with post-traumatic stress disorders in adults.