Smoking during pregnancy and hyperactivity-inattention in the offspring--comparing results from three Nordic cohorts

Association of perinatal factors with neurodevelopmental referrals in a population-based cohort study in Japan

Although the causes of neurodevelopmental disorders remain unknown, several environmental risk factors have attracted considerable attention. We conducted a retrospective, longitudinal, population-based cohort study using data from infant health examinations of children born to mothers with pregnancies between April 1, 2014 and March 31, 2016 in Kobe City to identify the perinatal factors associated with neurodevelopmental referrals in 3-year-old children. There were 15,223 and 1283 children in the normal and referral groups, respectively. Neurodevelopmental referrals at the health checkup for 3-year-old children were significantly associated with the lack of social support during pregnancy (adjusted odds ratio [aOR] 1.99, 99% CI 1.14-3.45, p = 0.001), history of psychiatric consultation (aOR 1.56, 99% CI 1.10-2.22, p = 0.001), no social assistance post-delivery (aOR 1.49, 99% CI 1.03-2.16, p = 0.006), Edinburgh Post-natal Depression Scale (EPDS) score ≥ 9 (aOR 1.36, 99% CI 1.01-1.84, p = 0.008), infant gender (male) (aOR 2.51, 99% CI 2.05-3.06, p < 0.001), and cesarean delivery (aOR 1.39, 99% CI 1.11-1.75, p < 0.001). In conclusion, this exploratory study in the general Japanese population identified six perinatal factors associated with neurodevelopmental referrals in 3-year-old children: infant gender (male), cesarean section, maternal history of psychiatric consultation, EPDS score ≥ 9, lack of social support during pregnancy, and no social assistance post-delivery.

Association of maternal physical and mental health characteristics with the hazard of having any medical condition or disability in Australian children: A 15-year birth cohort study

Any long-term medical condition or disability among children is a significant health issue. This study measured the incidence rate of any medical condition or disability among children from a nationally representative birth cohort, then used the random effect parametric survival regression model to assess whether the hazard of any medical condition or disability in children is associated with maternal physical and mental health characteristics (obesity, general health status, having a medical condition, stressful life events or mental illness). The study followed up 5019 children from the Longitudinal Study of Australian Children, assessing their time-to-event data from birth (2004) to 14 or 15 years of age (2018). The hazard rate of any medical condition or disability was 26.11 per 1000 person-years for all the children and 29.29 for the males-a noticeable gender difference. It was the highest (hazard rate: 62.90) among the children when their mothers had a medical condition, while the hazard rate was 22.40 per 1000 person-years among the children whose mothers had no medical conditions. The parametric panel regression results also suggested that the children of mothers with a medical condition during the 15-year study period were more likely to have a medical condition or disability (hazard ratio [HR]: 2.61, 95% confidence interval [CI]: 2.24-3.02) compared to the children of mothers with none. Similar trends were observed among children of mothers who had fair or poor general health (HR: 1.48, 95% CI: 1.15-1.91), obesity (HR: 1.40, 95% CI: 1.18-1.66) or experienced stressful life events (HR: 1.23, 95% CI: 1.06-1.43) over time compared to those whose mothers did not. These findings suggest that additional healthcare interventions targeting mothers with medical conditions, obesity, poor general health, or mental illness would help minimise the risk of medical conditions and disabilities among children.

Clustering of lifestyle and health behaviours in Australian adolescents and associations with obesity, self-rated health and quality of life

OBJECTIVE

The primary aim of this study was to identify clusters of lifestyle and health behaviours and explore their associations with health outcomes in a nationally representative sample of Australian adolescents.

METHODS

The study participants were 3127 adolescents aged 14-15 years who participated in the eighth wave of the birth cohort of the Longitudinal Study of Australian Children (LSAC). A latent class analysis (LCA) was performed to identify clusters based on the behaviours of physical activity, alcohol consumption, smoking, diet, eating disorders, sleep problems and weight consciousness. Multinomial logistic regression models were fitted to the following health outcome variables: obesity, self-rated general health and pediatric health-related quality of life, to investigate their associations with LCA clusters.

RESULTS

Based on the prevalence of health behaviour related characteristics, LCA identified gender based distinct clusters of adolescents with certain outward characteristics. There were five clusters for male and four clusters for female participants which are named as: healthy lifestyle, temperate, mixed lifestyle, multiple risk factors, and physically inactive (male only). Adolescents in the healthy lifestyle and temperate clusters reported low and moderately active health risk behaviours, for example, low physical activity, inadequate sleep and so on, while these behaviours were prevailing higher among adolescents of other clusters. Compared to adolescents of healthy lifestyle clusters, male members of physically inactive (OR = 3.87, 95% CI: 1.12 - 13.33) or mixed lifestyle (OR = 5.57, 95% CI: 3.15 - 9.84) clusters were over three to five times more likely to have obesity; while for female adolescents, members of only multiple risk factors clusters (OR = 3.61, 95% CI: 2.00 - 6.51) were over three time more likely to have obesity compared to their counterpart of healthy lifestyle clusters. Adolescents of physically inactive (b = -9.00 for male only), mixed lifestyle (b = -2.77 for male; b = -6.72 for female) or multiple risk factors clusters (b = -6.49 for male; b = -6.59 for female) had a stronger negative association with health-related quality of life scores compared to adolescents of healthy lifestyle clusters.

CONCLUSION

The study offers novel insights into latent class classification through the utilisation of different lifestyles and health-related behaviours of adolescents to identify characteristics of vulnerable groups concerning obesity, general health status and quality of life. This classification strategy may help health policy makers to target vulnerable groups and develop appropriate interventions.

Maternal health and health-related behaviours and their associations with child health: Evidence from an Australian birth cohort

Objective

This study investigates the associations between maternal health and health-related behaviours (nutrition, physical activity, alcohol consumption and smoking) both during pregnancy and up to 15 months from childbirth and children’s health outcomes during infancy and adolescence (general health, presence of a chronic illness, and physical health outcome index).

Methods

This study used Wave 1 (2004) and Wave 7 (2016) data from the Longitudinal Survey of Australian Children (LSAC). We measured mothers’ general health, presence of a medical condition during pregnancy and mental health during pregnancy or in the year after childbirth. We subsequently measured the children’s general health, presence of a medical condition, and physical health outcome index at ages 0–1 (infancy) and 12–13 (adolescence). Binary logistic and linear regression analyses were performed to examine the association between the mothers’ health-related variables and their children’s health.

Results

Our results showed that poor general health of the mother in the year after childbirth was associated with higher odds of poor health in infants and adolescents in all three dimensions: poor general health (OR: 3.13, 95% CI: 2.16–4.52 for infants; OR: 1.39, 95% CI: 0.95–2.04 for adolescents), presence of a chronic condition (OR: 1.47, 95% CI: 1.19–1.81 for adolescents) and lower physical health score (b = −0.94, p-value <0.05 for adolescents). Our study also revealed that the presence of a chronic condition in mothers during pregnancy significantly increased the likelihood of the presence of a chronic condition in their offspring during infancy (OR: 1.31, 95% CI: 1.12–1.54) and during adolescence (OR: 1.45, 95% CI: 1.20–1.75). The study found that stressful life events faced by mothers increase the odds of poor general health or any chronic illness during adolescence, while stress, anxiety or depression during pregnancy and psychological distress in the year after childbirth increase the odds of any chronic illness during infancy.

Conclusions

The present study found evidence that poor maternal physical and mental health during pregnancy or up to 15 months from childbirth has adverse health consequences for their offspring as measured by general health, presence of chronic health conditions, and physical health index scores. This suggests that initiatives to improve maternal physical and mental health would not only improve child health but would also reduce the national health burden.

Developmental Exposure to Air Pollution, Cigarettes, and Lead: Implications for Brain Aging

Brain development is impaired by maternal exposure to airborne toxins from ambient air pollution, cigarette smoke, and lead. Shared postnatal consequences include gray matter deficits and abnormal behaviors as well as elevated blood pressure. These unexpectedly broad convergences have implications for later life brain health because these same airborne toxins accelerate brain aging. Gene-environment interactions are shown for ApoE alleles that influence the risk of Alzheimer disease. The multigenerational trace of these toxins extends before fertilization because egg cells are formed in the grandmaternal uterus. The lineage and sex-specific effects of grandmaternal exposure to lead and cigarettes indicate epigenetic processes of relevance to future generations from our current and recent exposure to airborne toxins.

Impact of maternal smoking associated lyso-phosphatidylcholine 20:3 on offspring brain development

Maternal smoking during pregnancy affects fetal neurological development. Metabolomic studies in the general population suggest that smoking is associated with characteristic metabolic alterations. We investigated the association between the maternal smoking status, the fetal metabolome and head circumference at birth, as a surrogate parameter of brain development. 320 mother/newborn pairs of the Berlin Birth Cohort were investigated. Anthropometric parameters, including head circumference, of newborns of smoking mothers, former smoking mothers, and never smoking mothers were compared to assess the impact of maternal smoking behavior. Associations between maternal smoking behavior and 163 cord blood metabolites and associations between newborn head circumference and concentrations of smoking behavior related metabolites were analysed. Male newborns of smoking mothers had a reduced head circumference when compared with newborns from former smoking and never smoking mothers (p < 0.05). Using linear regression models corrected for established confounding factors, maternal smoking during pregnancy showed an independent association with head circumference (95% CI: -0.75～-0.41 cm, p = 2.45×10^-11). In a stepwise linear regression model corrected for known confounding factors of brain growth lyso-phosphatidylcholine 20:3 (95% CI: 6.68～39.88 cm, p = 4.62×10^-4) was associated with head circumference in male offspring only. None of the metabolites were associated with head circumference of female newborns. In conclusion, maternal smoking during pregnancy impacted on male offspring's development including brain development. The smoking related metabolite lyso-phosphatidylcholine 20:3 was associated with head circumference of male offspring.

Familial confounding of the association between maternal smoking in pregnancy and autism spectrum disorder in offspring

Evidence supports no link between maternal smoking in pregnancy and autism spectrum disorder (autism) overall. To address remaining questions about the unexplained heterogeneity between study results and the possibility of risk for specific autism sub-phenotypes, we conducted a whole-population cohort study in Denmark. We followed births 1991-2011 (1,294,906 persons, including 993,301 siblings in 728,271 families), from 1 year of age until an autism diagnosis (13,547), death, emigration, or December 31, 2012. Autism, with and without attention deficit hyperactivity disorder (ADHD) and with and without intellectual disability (ID) were based on ICD-8 and ICD-10 codes from Danish national health registers, including 3,319 autism + ADHD, 10,228 autism - no ADHD, 2,205 autism + ID, and 11,342 autism - no ID. We estimated hazard ratios (HRs) and 95% confidence intervals (95% CIs) between any maternal smoking (from birth records) and autism (or sub-phenotypes) using survival models with robust standard errors, stratifying by birth year and adjusting for child sex, parity, and parental age, education, income, and psychiatric history. To additionally address confounding using family designs, we constructed a maternal cluster model (adjusting for the smoking proportion within the family), and a stratified sibling model. Associations with maternal smoking and autism were elevated in conventional adjusted analyses (HR of 1.17 [1.13-1.22]) but attenuated in the maternal cluster (0.98 [0.88-1.09]) and sibling (0.86 [0.64-1.15]) models. Similarly, risks of autism sub-phenotypes with maternal smoking were attenuated in the family-based models. Together these results support that smoking in pregnancy is not linked with autism or select autism comorbid sub-phenotypes after accounting for familial confounding. Autism Res 2020, 13: 134-144. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Smoking during pregnancy has many harmful impacts, which may include harming the baby's developing brain. However, in a study of thousands of families in Denmark, it does not appear that smoking in pregnancy leads to autism or autism in combination with intellectual problems or attention deficits, once you account for the way smoking patterns and developmental disabilities run in families.

Prenatal Cotinine Levels and ADHD Among Offspring

OBJECTIVES

An association between maternal smoking during pregnancy and offspring attention-deficit/hyperactivity disorder (ADHD) has been shown across several studies based on self-reports. No previous studies have investigated the association of nicotine exposure measured by cotinine levels during pregnancy and offspring ADHD.

METHODS

In this population-based study, 1079 patients born between 1998 and 1999 and diagnosed with ADHD according to the International Classification of Diseases and 1079 matched controls were identified from Finnish nationwide registers. Maternal cotinine levels were measured by using quantitative immunoassays from maternal serum specimens collected during the first and second trimesters of pregnancy and archived in the national biobank.

RESULTS

There was a significant association between increasing log-transformed maternal cotinine levels and offspring ADHD. The odds ratio was 1.09 (95% confidence interval [CI] 1.06-1.12) when adjusting for maternal socioeconomic status, maternal age, maternal psychopathology, paternal age, paternal psychopathology, and child's birth weight for gestational age. In the categorical analyses with cotinine levels in 3 groups, heavy nicotine exposure (cotinine level >50 ng/mL) was associated with offspring ADHD, with an odds ratio of 2.21 (95% CI 1.63-2.99) in the adjusted analyses. Analyses by deciles of cotinine levels revealed that the adjusted odds for offspring ADHD in the highest decile was 3.34 (95% CI 2.02-5.52).

CONCLUSIONS

The study reveals an association with and a dose-response relationship between nicotine exposure during pregnancy and offspring ADHD. Future studies incorporating maternal smoking and environmental, genetic, and epigenetic factors are warranted.

Psychiatric research in the Northern Finland Birth Cohort 1986 - a systematic review

The Northern Finland Birth Cohort 1986 is a large population-based birth cohort, which aims to promote health and wellbeing of the population. In this paper, we systematically review the psychiatric research performed in the cohort until today, i.e. at the age of 32 years of the cohort (2018). We conducted a systematic literature search using the databases of PubMed and Scopus and complemented it with a manual search. We found a total of 94 articles, which were classified as examining ADHD, emotional and behavioural problems, psychosis risk or other studies relating to psychiatric subjects. The articles are mainly based on two large comprehensive follow-up studies of the cohort and several substudies. The studies have often used also nationwide register data. The studies have found several early predictors for the aforementioned psychiatric outcomes, such as problems at pregnancy and birth, family factors in childhood, physical inactivity and substance use in adolescence. There are also novel findings relating to brain imaging and cognition, for instance regarding familial risk of psychosis in relation to resting state functional MRI. The Northern Finland Birth Cohort 1986 has been utilised frequently in psychiatric research and future data collections are likely to lead to new scientifically important findings.

Abbreviations: attention deficit hyperactivity disorder (ADHD); magnetic resonance imaging (MRI)

Prenatal maternal smoking, maternal offending, and offspring behavioural and cognitive outcomes in early childhood

BACKGROUND

Maternal smoking during pregnancy and parental offending are both linked to adverse offspring outcomes. Few studies have examined how these exposures together influence diverse offspring outcomes in early childhood.

AIMS

To examine associations between quantity of prenatal maternal smoking and frequency of maternal offending and offspring behavioural and cognitive outcomes at age 5 years.

METHODS

Over 66,000 Australian children (mean age 5.6 years) were drawn from an intergenerational data linkage study. Unadjusted and adjusted logistic regressions were conducted for the two key exposures (maternal prenatal smoking and mother having at least two criminal convictions) and offspring behavioural and cognitive vulnerabilities. Population attributable fractions (PAFs) were also estimated for each outcome for the two exposures.

RESULTS

Prenatal smoking and maternal offending were, separately and together, associated with most of the developmental vulnerabilities examined, even after adjusting for other familial and prenatal risk factors. PAFs for prenatal smoking ranged from 5.3% to 15.8%, and PAFs for maternal offending ranged from 3.4% to 11.8% across the offspring outcomes.

CONCLUSIONS

Maternal smoking during pregnancy and maternal offending were uniquely associated with a range of offspring vulnerabilities, but mothers who smoked during pregnancy tended to experience multiple problems that should also be considered as indicators of child vulnerabilities. While early behavioural difficulties were evident in these children, it was striking that they were also likely to have cognitive vulnerabilities. Early intervention to support cognitive development in these children may minimise their risk of academic underachievement, long-term disadvantage, and even offending.

Maternal smoking during pregnancy and cord blood DNA methylation: new insight on sex differences and effect modification by maternal folate levels

Maternal smoking during pregnancy may affect newborn DNA methylation (DNAm). However, little is known about how these associations vary by a newborn's sex and/or maternal nutrition. To fill in this research gap, we investigated epigenome-wide DNAm associations with maternal smoking during pregnancy in African American mother-newborn pairs. DNAm profiling in cord (n = 379) and maternal blood (n = 300) were performed using the Illumina HumanMethylation450 BeadChip array. We identified 12 CpG sites whose DNAm levels in cord blood were associated with maternal smoking, at a false discovery rate <5%. The identified associations in the GFI1 gene were more pronounced in male newborns than in females (P = 0.002 for maternal smoking × sex interaction at cg18146737). We further observed that maternal smoking and folate level may interactively affect cord blood DNAm level at cg05575921 in the AHRR gene (P = 5.0 × 10-4 for interaction): compared to newborns unexposed to maternal smoking and with a high maternal folate level (>19.2 nmol/L), the DNAm level was about 0.03 lower (P = 3.6 × 10-4) in exposed newborns with a high maternal folate level, but was 0.08 lower (P = 1.2 × 10-8) in exposed newborns with a low maternal folate level. Our data suggest that adequate maternal folate levels may partly counteract the impact of maternal smoking on DNAm. These findings may open new avenues of inquiry regarding sex differences in response to environmental insults and novel strategies to mitigate their intergenerational health effects through optimization of maternal nutrition.

Pre-conceptual and prenatal supplementary folic acid and multivitamin intake, behavioral problems, and hyperkinetic disorders: A study based on the Danish National Birth Cohort (DNBC)

OBJECTIVE

To evaluate whether early folic acid or multivitamin supplementation during pregnancy prevents diagnosis of hyperkinetic disorders (HKD), treatment for attention deficit hyperactivity disorder (ADHD), and ADHD-like behaviors reported by parents participating in the DNBC for children at age 7.

METHODS

HKD diagnosis and ADHD medication use data were obtained from the Danish National Hospital, Central Psychiatric and Pharmaceutical registers. We estimated hazard ratios (HRs) for HKD diagnosis and ADHD medication use and risk ratios (RRs) for parent-reported ADHD behavior collected with the Strength and Difficulties Questionnaire (SDQ), comparing children whose mothers took folic acid or multivitamin supplements early in pregnancy defined as starting periconceptionally (4 weeks prior to their last menstrual period (LMP)) through 8 weeks after their LMP (4-8 weeks), to children whose mothers indicated no supplement use for the same entire period.

RESULTS

We identified 384 children (1.1%) with a hospital diagnosis for HKD and 642 children (1.8%) treated with ADHD medication. We found no association between risk of HKD diagnosis or intake of ADHD medication and early maternal folic acid use. However, early multivitamin use was associated with an approximately 30% reduction in risk for HKD diagnosis (aHR: 0.70, 95% CI: 0.52-0.96) and 21% reduction in treatment with ADHD medication (aHR: 0.79, 95% CI: 0.62-0.98). We observed a reduced risk in parent-reported ADHD behaviors, but these results were attenuated after adjustment.

CONCLUSION

Our data suggest that multivitamin use in early pregnancy may reduce risk for HKD diagnosis and treatment for ADHD in the offspring.

Re-examining the link between prenatal maternal anxiety and child emotional difficulties, using a sibling design

Background

Prenatal exposure to maternal anxiety has been associated with child emotional difficulties in a number of epidemiological studies. One key concern, however, is that this link is vulnerable to confounding by pleiotropic genes or environmental family factors.

Methods

Data on 82 383 mothers and children from the population-based Mother and Child Cohort Study and data on 21 980 siblings were used in this study. Mothers filled out questionnaires for each unique pregnancy, for infant difficulties at 6 months and for emotional difficulties at 36 months. The link between prenatal maternal anxiety and child difficulties were examined using logistic regression analyses and multiple linear regression analyses for the full study sample and the sibling sample.

Results

In the conventional full-cohort analyses, prenatal exposure to maternal anxiety was associated with child difficulties at both 6 months [odds ratio (OR) = 2.1 (1.94-2.27)] and 36 months [OR = 2.72 (2.47-2.99)]. The findings were essentially the same whether we examined difficulties at 6 months or at 36 months. However, these associations were no longer present once we controlled for potential social and genetic confounders in the sibling comparison analyses, either at 6 months [OR = 1.32 (0.91-1.90)] or at 36 months [OR = 1.28 (0.63-2.60)]. Findings from multiple regression analyses with continuous measures were essentially the same.

Conclusions

Our finding lends little support for there being an independent prenatal effect on child emotional difficulties; rather, our findings suggest that the link between prenatal maternal anxiety and child difficulties could be confounded by pleiotropic genes or environmental family factors.

Further evidence for the role of pregnancy-induced hypertension and other early life influences in the development of ADHD: results from the IDEFICS study

The aim of this study is to investigate whether in addition to established early risk factors other, less studied pre-, peri-, and postnatal influences, like gestational hypertension or neonatal respiratory disorders and infections, may increase a child's risk of developing attention-deficit/hyperactivity disorders (ADHD). In the IDEFICS study more than 18,000 children, aged 2-11.9 years, underwent extensive medical examinations supplemented by parental questionnaires on pregnancy and early childhood. The present analyses are restricted to children whose parents also completed a supplementary medical questionnaire (n = 15,577), including the question whether or not the child was ever diagnosed with ADHD. Multilevel multivariable logistic regression was used to assess the association between early life influences and the risk of ADHD. Our study confirms the well-known association between maternal smoking during pregnancy and a child's risk of ADHD. In addition, our study showed that children born to mothers younger than 20 years old were 3-4 times more likely to develop ADHD as compared to children born to mothers aged 25 years and older. Moreover, we found that children whose mothers suffered from pregnancy-induced hypertension had an approximately twofold risk of ADHD (OR 1.95; 95% CI 1.09-3.48). This also holds true for infections during the first 4 weeks after birth (OR 2.06; 95% CI 1.05-4.04). In addition, although not statistically significant, we observed a noticeable elevated risk estimate for neonatal respiratory disorders (OR 1.76; 95% CI 0.91-3.41). Hence, we recommend that these less often studied pre-, peri, and postnatal influences should get more attention when considering early indicators or predictors for ADHD in children. However, special study designs such as genetically sensitive designs may be needed to derive causal conclusions.

Maternal Smoking During Pregnancy Is Associated With Offspring's Musculoskeletal Pain in Adolescence: Structural Equation Modeling

Introduction

Smoking and behavioral problems are related to musculoskeletal (MS) pain in adolescence. Maternal smoking during pregnancy (MSDP) is associated with offspring's behavioral problems but its relation to MS pain in adolescence is unknown. Our purpose was to investigate whether there is an association between MSDP, the number of pain sites in adolescence, and the factors that potentially mediate this relationship.

Methods

We evaluated the association of MSDP with offspring's MS pain at 16 years among participants of the Northern Finland Birth Cohort 1986 (n = 6436, 3360 girls, 68% of all births) using Chi-square test and independent samples t test. We used structural equation modeling to assess the mediating factors stratified by gender.

Results

MSDP was frequent (22%) associating with paternal smoking (p < .001), externalization problems at 8 years (p = .009 boys, p = .002 girls), offspring's smoking at 16 years (p < .001), externalizing problems at 16 years (p < .001), family's social class (p < .001) and intactness of the family status (p < .001). The mean number of offspring's MS pain sites was higher among adolescents whose mothers had smoked during pregnancy than among those whose mothers were nonsmokers (p = .002 boys, p = .012 girls). The association between MSDP and MS pain at 16 years was mediated by externalizing problems at 8 years (p < .001) and 16 years (p < 0.001).

Conclusions

MSDP increased the risk of offspring's MS pain in adolescence, and the association was mediated by offspring's externalizing problems during childhood and early adolescence.

Implications

This study indicates that MSDP increases the risk of MS pain in adolescence and the effect is mediated by externalizing problems. Our results add to the evidence on harmfulness of MSDP for offspring, and can be used as additional information in interventions aiming to influence MSDP.

Familial confounding of the association between maternal smoking during pregnancy and internalizing disorders in offspring

BACKGROUND

Maternal smoking has consistently been associated with multiple adverse childhood outcomes including externalizing disorders. In contrast the association between maternal smoking during pregnancy (MSDP) and internalizing (anxiety and depressive) disorders in offspring has received less investigation.

METHOD

We conducted a nationwide cohort study including 957635 individuals born in Denmark between 1991 and 2007. Data on MSDP and diagnoses of depression or anxiety disorders were derived from national registers and patients were followed up from the age of 5 years to the end of 2012. Hazard rate ratios (HRRs) were estimated using stratified Cox regression models. Sibling data were used to disentangle individual- and familial-level effects of MSDP and to control for unmeasured familial confounding.

RESULTS

At the population level, offspring exposed to MSDP were at increased risk for both severe depression [HRR 1.29, 95% confidence interval (CI) 1.22-1.36] and severe anxiety disorders (HRR 1.26, 95% CI 1.20-1.32) even when controlling for maternal and paternal traits. However, there was no association between MSDP and internalizing disorders when controlling for the mother's propensity for MSDP (depression: HRR 1.11, 95% CI 0.94-1.30; anxiety disorders: HRR 0.94, 95% CI 0.80-1.11) or comparing differentially exposed siblings (depression: HRR 1.18, 95% CI 0.75-1.89; anxiety disorders: HRR 0.87, 95% CI 0.55-1.36).

CONCLUSIONS

The results suggest that familial background factors account for the association between MSDP and severe internalizing disorders not the specific exposure to MSDP.

Perinatal smoking exposure and behavioral problems in Japanese children aged 5 years: The Kyushu Okinawa Maternal and Child Health Study

BACKGROUND

Epidemiological evidence regarding the relationship between maternal secondhand smoke (SHS) exposure during pregnancy and postnatal SHS exposure and childhood behavioral problems is scarce.

OBJECTIVE

The present prebirth cohort study investigated the association between perinatal smoking exposure and behavioral problems in Japanese children aged 5 years.

METHODS

Subjects were 1200 mother-child pairs. Data on variables under study were obtained using parent questionnaires. Emotional problems, conduct problems, hyperactivity problems, and peer problems were assessed using the Strengths and Difficulties Questionnaire. Adjustment was made for maternal age, gestation at baseline, region of residence at baseline, number of children at baseline, maternal and paternal education, household income, maternal depressive symptoms during pregnancy, maternal alcohol intake during pregnancy, child's birth weight, child's sex, and breastfeeding duration.

RESULTS

Maternal smoking during pregnancy was independently associated with increased risk of conduct problems and hyperactivity problems (adjusted odds ratios: ORs [95% confidence intervals: CIs]=1.93 [1.15-3.17] and 1.89 [1.03-3.33], respectively). Maternal SHS exposure at work during pregnancy was independently positively related to conduct problems and hyperactivity problems (adjusted ORs [95% CI]=1.54 [1.01-2.31] and 1.69 [1.04-2.67], respectively). Smoking by any household member, and especially by the child's father, during the first year of life was independently associated with an increased risk of emotional problems (adjusted ORs [95% CI]=1.55 [1.06-2.26] and 1.63 [1.11-2.40], respectively).

CONCLUSIONS

Maternal smoking and maternal SHS exposure at work during pregnancy may increase the risk of conduct problems and hyperactivity problems. Smoking by any household member, and especially by the child's father, may increase the risk of emotional problems.

Smoking during pregnancy: A population-based study

AIMS

Tobacco is a major cause of disease and mortality in modern times. The risk of smoking in pregnancy is a serious threat to the development and future health of an unborn child. The aim of this study was to explore the epidemiological factors associated with smoking during pregnancy in a primary healthcare setting.

METHODS

All 856 maternity records at the Glaesibaer Health Care Centre in Reykjavik during 2006-2013 were reviewed and information on smoking habits investigated.

RESULTS

The records showed that in 108 (12.2%) pregnancies, women smoked at first visit and 63 stopped smoking in early pregnancy, leaving 45 (5.3%) mothers smoking throughout the whole gestational period. The mean age of the smoking women was 27.8 years and for the non-smokers 29.7 years. Low social status (odds ratio (OR) = 2.66; 95% confidence interval (CI): 1.19-5.96), previous mental health diagnosis (OR = 2.7; 95% CI: 1.3-5.6), and unstable relationship with a partner (OR = 3.78; 95% CI: 2.1-7.0) were associated with smoking. Smoking fewer cigarettes was associated with a 0.04-unit lower risk of smoking during pregnancy (OR = 0.04: 95% CI: 0.02-0.08).

CONCLUSIONS

Our results indicated that the women who smoked during pregnancy were often heavy smokers and living without a partner. They were younger, had worse mental health, and a lower social status than those pregnant women who did not smoke. Bearing in mind the consequence of smoking in pregnancy, this subgroup should get increased assistance to quit smoking before and during early pregnancy, as well as appropriate medical and social support.

Prenatal smoking exposure and neuropsychiatric comorbidity of ADHD: a finnish nationwide population-based cohort study

BACKGROUND

Prenatal smoking exposure has been associated with attention-deficit/hyperactivity disorder (ADHD). ADHD is commonly associated with a wide spectrum of psychiatric comorbidity. The association between smoking and neuropsychiatric comorbidity of ADHD has remained understudied. The aim of this study is to examine the association between prenatal exposure to maternal smoking and offspring ADHD, and test whether the smoking-ADHD associations are stronger when ADHD is accompanied by other lifetime neuropsychiatric comorbidities.

METHODS

The study is based on a nested case-control design and includes all Finnish singletons born between 1991 and 2005 and diagnosed with ADHD by 2011 (n = 10,132), matched with four controls (n = 38,811) on date of birth, sex and residence in Finland.

RESULTS

The risk for ADHD with or without comorbidity was significantly increased among offspring exposed to maternal smoking on adjusting for potential confounders (OR = 1.75, CI 95 % = 1.65-1.86). Compared to the only ADHD cases, subjects with comorbid conduct disorder or oppositional defiant disorder had a significantly stronger association with smoking exposure (OR = 1.80, CI 95 % = 1.55-2.11).

CONCLUSIONS

Prenatal smoking represents an important risk factor for the ADHD comorbid with CD/ODD. Further research on the association between prenatal smoking exposure and neuropsychiatric comorbidity of ADHD is needed considering the increased risk among these subjects of an overall poor health outcome as compared to only ADHD. In particular, studies utilizing biomarkers or including subjects with neuropsychiatric conditions with and without comorbid ADHD are needed.

Annual Research Review: Threats to the validity of child psychiatry and psychology

BACKGROUND

Suggestions have been made that many claims concern false-positive findings in the field of child psychology and psychiatry.

FINDINGS

The literature was searched for concepts and findings on the validity of child psychiatry and psychology. Substantial progress has been made in some, but not all, areas and considerable challenges remain in all.

CONCLUSIONS

The two major threats to validity concern the inability to examine brain tissues in life and the evidence that there is a high overlap among disorders. We emphasize the need to follow published guidelines on preplanned analyses and we note the dangers associated with unregulated flexibility in data analysis. We note the very important clinical and developmental findings that have been ignored, perhaps partly because of an excessive focus on technologies. Nevertheless, we are positive about both the accomplishments and the ways in which challenges are being met.

Tobacco smoking during pregnancy and risk of adverse behaviour in offspring: A follow-up study

OBJECTIVES

This study examines associations between prenatal exposure to tobacco smoking and adverse behaviour in the offspring.

METHODS

We included 1016 pregnant women from Greenland and Ukraine (526 from Greenland and 490 from Ukraine). Serum cotinine measurements were used to identify smoking pregnant women. When the children were from five to nine years of age, the parents assessed the child's behaviour using the Strength and Difficulties Questionnaire (SDQ).

RESULTS

Overall, smoking in pregnancy was not associated with a higher probability of adverse behaviour assessed by the total SDQ score. However, in the crude analysis smoking was associated with a higher mean difference of SDQ-total score. In Greenland the SDQ-total mean difference (MD) was (MD (95% CI)=1.31 points (0.42; 2.19)) and in Ukraine (MD (95% CI)=0.18 points (-1.2; 0.91)), whereas the adjusted mean differences were statistically non-significant.

CONCLUSIONS

In utero exposure to tobacco smoking was not associated with a significant higher risk of adverse behaviour in the offspring, but elevated risk of adverse behaviour among children prenatally exposed to smoking cannot be excluded.

A pilot study of home-based smoking cessation programs for rural, appalachian, pregnant smokers

OBJECTIVE

To evaluate a web-based contingency management program (CM) and a phone-delivered cessation counseling program (Smoking Cessation for Healthy Births [SCHB]) with pregnant smokers in rural Appalachia who were ≤12 weeks gestation at enrollment.

DESIGN

Two group randomized design.

SETTING

Home-based cessation programs in rural Appalachia Ohio and Kentucky.

PARTICIPANTS

A community sample of pregnant smokers (N = 17).

METHODS

Participants completed demographic and smoking-related questionnaires and were assigned to CM (n = 7) or SCHB (n = 10) conditions. Smoking status was assessed monthly using breath carbon monoxide and urinary cotinine.

RESULTS

For CM, two of seven (28.57%) of the participants achieved abstinence, and three of 10 (30%) of those enrolled in SCHB were abstinent by late in pregnancy. Participants in CM attained abstinence more rapidly than those in SCHB. However, those in SCHB experienced less relapse to smoking, and a greater percentage of these participants reduced their smoking by at least 50%.

CONCLUSION

Based on this initial evaluation, the web-based CM and SCHB programs appeared to be feasible for use with rural pregnant smokers with acceptable program adherence for both approaches. Future researchers could explore combining these programs to capitalize on the strengths of each, for example, rapid smoking cessation based on CM incentives and better sustained cessation or reductions in smoking facilitated by the counseling support of SCHB.

The effects of prenatal exposure to alcohol and environmental tobacco smoke on risk for ADHD: a large population-based study

Attention deficit hyperactivity disorder (ADHD) is caused by the interaction of genetic and environmental factors. The objective of this study was to examine the effects of prenatal exposure to alcohol and environmental tobacco smoke (ETS). Among the 30,552 parents who responded to a survey, the answers of 19,940 who replied to questions on prenatal exposure to ETS, alcohol consumption, and completed the DuPaul Rating Scale were analyzed. Results revealed that risk of ADHD significantly increased as a result of exposure to alcohol by 1.55 times (95% CI 1.33-1.82), maternal smoking during pregnancy by 2.64 times (95% CI 1.45-4.80), and paternal smoking during pregnancy by 1.17 times (95% CI 1.98-1.39). When the subjects whose mothers did not smoke during pregnancy were divided into 4 groups, the prevalence was 1.16 times higher (95% CI 1.02-1.33) in the group exposed to ETS but not alcohol, 1.19 times higher (95% CI 0.91-1.57) in the group exposed to alcohol but not ETS, and 1.58 times higher (95% CI 1.31-1.91) in the group exposed to ETS and alcohol. The differences between the groups were statistically significantly (P<0.0001). This result shows that simultaneous exposure to ETS and alcohol during pregnancy increases the risk of ADHD.

Parental smoking during pregnancy and ADHD in children: the Danish national birth cohort

BACKGROUND

Prenatal maternal smoking has been associated with attention-deficit/hyperactivity disorder (ADHD) in children, but the causal nature of this association is still under scrutiny. We examined the association with maternal smoking and nicotine replacement use during pregnancy, using association with paternal smoking as a marker of potential genetic or social confounding.

METHODS

We included 84 803 singletons who participated in the Danish National Birth Cohort. Information on parental smoking was reported by the mothers during pregnancy. Children with ADHD were identified from the Danish Psychiatric Central Register, the Danish National Patient Register, and the Register of Medicinal Product Statistics by the International Classification of Diseases, 10th Revision diagnosis or medication. We also used hyperactivity/inattention score of the parent-reported Strengths and Difficulties Questionnaire, included in the 7-year follow-up of the National Birth Cohort.

RESULTS

Maternal and paternal smoking during pregnancy were associated with an elevated risk of ADHD defined by hospital diagnosis, medication, and hyperactivity/inattention score, but the association was stronger for maternal smoking than for paternal smoking. Compared with children born to nonsmoking mothers and smoking fathers, children born of smoking mothers and nonsmoking fathers had a higher risk of ADHD (adjusted hazard ratio = 1.26; 95% confidence interval, 1.03 to 1.53). We also saw a higher risk of ADHD in children of mothers who used nicotine replacement during pregnancy.

CONCLUSIONS

Our findings indicate that the association between prenatal maternal smoking and ADHD may overestimate a causal link, but nicotine exposure or related factors may still play a causal role.

Prenatal tobacco exposure and response inhibition in school-aged children: an event-related potential study

Prenatal cigarette smoke exposure (PCSE) has been linked to problems in behavioral inhibition and attention deficit hyperactivity disorder in children in several epidemiological studies. We used event-related potentials (ERPs) to examine the effects of PCSE on neural correlates of inhibitory control of behavior. In a prospective longitudinal study on child development in the Canadian Arctic, we assessed 186 Inuit children (mean age=11.3years) on a visual Go/No-go response inhibition paradigm. PCSE was assessed through maternal recall. Potential confounders were documented from a maternal interview, and exposure to neurotoxic environmental contaminants was assessed from umbilical cord and child blood samples. PCSE was not related to behavioral performance on this simple response inhibition task. Nevertheless, this exposure was associated with smaller amplitudes of the N2 and P3 components elicited by No-go stimuli, suggesting an impairment in the neural processes underlying response inhibition. Amplitude of the No-go P3 component was also inversely associated with behavioral measures of externalizing problems and hyperactivity/impulsivity in the classroom. This study is the first to report neurophysiological evidence of impaired response inhibition in school-aged children exposed to tobacco smoke in utero. Effects were found on ERP components associated with conflict processing and inhibition of a prepotent response, indicating neurophysiological deficits that may play a critical role in the attention and behavior problems observed in children with PCSE.

Exposure to neurotoxicants and the development of attention deficit hyperactivity disorder and its related behaviors in childhood

The purpose of this manuscript is to review the literature to determine evidence of associations between exposure to prenatal and postnatal environmental agents and the development of attention deficit hyperactivity disorder (ADHD) and related behaviors. A review of published research literature was conducted on associations between exposures to prenatal and postnatal cigarette smoke, prenatal exposure to alcohol, cocaine, and heroin, childhood exposure to lead, and prenatal exposure to organophosphate pesticides and outcomes of ADHD or behaviors related to ADHD. Review of the literature in these areas provides some evidence of associations between each of the exposures and ADHD-related behaviors, with the strongest evidence from prenatal cigarette and alcohol exposure and postnatal lead exposure. However, research on each exposure also produced evidence of weaknesses in these hypothesized links due to imprecise research methodologies and issues of confounding and inaccurate covariate adjustment. More rigorous studies are needed to provide definitive evidence of associations between each of these prenatal or postnatal exposures and the development of ADHD or symptoms of ADHD. Future studies need to clarify the underlying mechanisms between these exposures and the increased risk for ADHD and associated behaviors. More research is also needed utilizing study designs that include genetic information, as ADHD is highly heritable and there appear to be some protective mechanisms offered by certain genetic characteristics as evidenced in gene by environmental studies. Finally, while studies focusing on individual drugs and chemicals are an important first step, we cannot ignore the fact that children are exposed to combinations of drugs and chemicals, which can interact in complex ways with each other, as well as with the child's genetic makeup and psychosocial environment to influence ADHD risk.

Prenatal cigarette smoke exposure causes hyperactivity and aggressive behavior: role of altered catecholamines and BDNF

Smoking during pregnancy is associated with a variety of untoward effects on the offspring. However, recent epidemiological studies have brought into question whether the association between neurobehavioral deficits and maternal smoking is causal. We utilized an animal model of maternal smoking to determine the effects of prenatal cigarette smoke (CS) exposure on neurobehavioral development. Pregnant mice were exposed to either filtered air or mainstream CS from gestation day (GD) 4 to parturition for 4h/d and 5d/wk, with each exposure producing maternal plasma concentration of cotinine equivalent to smoking <1 pack of cigarettes per day (25ng/ml plasma cotinine level). Pups were weaned at postnatal day (PND) 21 and behavior was assessed at 4weeks of age and again at 4-6months of age. Male, but not female, offspring of CS-exposed dams demonstrated a significant increase in locomotor activity during adolescence and adulthood that was ameliorated by methylphenidate treatment. Additionally, male offspring exhibited increased aggression, as evidenced by decreased latency to attack and number of attacks in a resident-intruder task. These behavioral abnormalities were accompanied by a significant decrease in striatal and cortical dopamine and serotonin and a significant reduction in brain-derived neurotrophic factor (BDNF) mRNA and protein. Taken in concert, these data demonstrate that prenatal exposure to CS produces behavioral alterations in mice that are similar to those observed in epidemiological studies linking maternal smoking to neurodevelopmental disorders. Further, these data also suggest a role for monaminergic and BDNF alterations in these effects.

Prenatal glucocorticoid treatment and later mental health in children and adolescents

Background

Animal studies demonstrate a clear link between prenatal exposure to glucocorticoids (GC) and altered offspring brain development. We aim to examine whether prenatal GC exposure programs long-term mental health in humans.

Methods

Using propensity-score-matching, children prenatally exposed to synthetic glucocorticoids (sGC), n=37, and controls, n=185, were balanced on important confounders related to sGC treatment - gestational age and pre-pregnancy BMI. We also used mixed-effects modeling to analyse the entire cohort – matching each sGC case, n=37, to all possible controls, n=6079, on gestational age and sex. We obtained data from the Northern Finland Birth Cohort 1986 at four waves – pregnancy, birth, 8 and 16 years. Data on pregnancy and birth outcomes came from medical records. Mental health was assessed at 8 years by teachers with the Rutter B2 scale, and at 16 years by parents with the Strengths and Weaknesses of ADHD symptoms and Normal behavior (SWAN) scale and adolescents by the Youth Self-Report (YSR) scale.

Results

Prenatal sGC treatment was consistently associated with adverse mental health in childhood and adolescence, as shown by both the propensity-score method and mixed-effects model. Using the propensity-score-matched subsample, linear multiple regression showed prenatal sGC was significantly linked with general psychiatric disturbance (B=8.34 [95% CI: .23-16.45]) and inattention (B= .97 [95% CI: .16-1.80]) at 8 years after control for relevant confounders. Similar findings were obtained at 16 years, but did not reach statistical significance. Mediation by birthweight/placental weight was not detected.

Conclusions

This study is the first to prospectively investigate the long-term associations between prenatal exposure to sGC treatment and mental health in children and adolescents. We report an association between prenatal exposure to sGC and child mental health, supportive of the idea that sGC has a programming effect on the fetal brain.

Evaluation of attention-deficit hyperactivity disorder risk factors

Background. Attention-deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders among children. The aim of this study was to evaluate risk factors for ADHD in children. Method. In this case-control study, 404 children between 4 and 11 years old were selected by cluster sampling method from preschool children (208 patients as cases and 196 controls). All the participants were interviewed by a child and adolescent psychiatrist to survey risk factors of ADHD. Results. Among cases, 59.3% of children were boys and 38.4% were girls, which is different to that in control group with 40.7% boys and 61.6% girls. The chi-square showed statistically significance (P value < 0.0001). The other significant factors by chi-square were fathers' somatic or psychiatric disease (P value < 0.0001), history of trauma and accident during pregnancy (P value = 0.039), abortion proceeds (P value < 0.0001), unintended pregnancy (P value < 0.0001), and history of head trauma (P value < 0.0001). Conclusions. Findings of our study suggest that maternal and paternal adverse events were associated with ADHD symptoms, but breast feeding is a protective factor.

Maternal active and passive smoking and hypertensive disorders of pregnancy: risk with trimester-specific exposures

BACKGROUND

The inverse association between prenatal smoking and preeclampsia is puzzling, given the increased risks of prematurity and low birthweight associated with both smoking and preeclampsia. We analyzed the Norwegian Mother and Child Birth Cohort (MoBa) to determine whether the associations varied by timing of prenatal smoking.

METHODS

We conducted an analysis of 74,439 singleton pregnancies with completed second- and third- trimester questionnaires. Active and passive smoke exposure by trimester were determined by maternal self-report, and covered the period of preconception through approximately 30 weeks' gestation. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

Rates of active smoking declined dramatically during pregnancy: for trimester 1, 23%; trimester 2, 9%; and trimester 3, 8%. Active smoking in the third trimester was associated with reduced odds of preeclampsia and gestational hypertension, with the strongest association among continuous smokers (for preeclampsia, OR= 0.57 [95% CI = 0.46-0.70]). Women who quit smoking before the third trimester had approximately the same risk of preeclampsia and gestational hypertension as nonsmokers. There was some evidence of dose-response, with the heaviest smokers (more than eight cigarettes per day) having the lowest risks of preeclampsia (0.48 [0.32-0.73]) and gestational hypertension (0.51 [0.28-0.95]). There was little evidence of an association with passive smoking exposure.

CONCLUSION

The association between smoking and preeclampsia varies substantially according to the timing and intensity of exposure. A better understanding of the biologic pathways that underlie these associations may provide important clues to the etiology of preeclampsia and the development of effective clinical interventions.

Associations between prenatal cigarette smoke exposure and externalized behaviors at school age among Inuit children exposed to environmental contaminants

BACKGROUND

Smoking during pregnancy is common among Inuit women from the Canadian Arctic. Yet prenatal cigarette smoke exposure (PCSE) is seen as a major risk factor for childhood behavior problems. Recent data also suggest that co-exposure to neurotoxic environmental contaminants can exacerbate the effects of PCSE on behavior. This study examined the association between PCSE and behavior at school age in a sample of Inuit children from Nunavik, Québec, where co-exposure to environmental contaminants is also an important issue. Interactions with lead (Pb) and mercury (Hg), two contaminants associated with behavioral problems, were also explored.

METHODS

Participants were 271 children (mean age=11.3years) involved in a prospective birth-cohort study. PCSE was assessed through maternal recall. Assessment of child behavior was obtained from the child's classroom teacher on the Teacher Report Form (TRF) and the Disruptive Behavior Disorders Rating Scale (DBD). Exposure to contaminants was assessed from umbilical cord and child blood samples. Other confounders were documented by maternal interview.

RESULTS

After control for contaminants and confounders, PCSE was associated with increased externalizing behaviors and attention problems on the TRF and higher prevalence of attention deficit hyperactivity disorder (ADHD) assessed on the DBD. No interactions were found with contaminants.

INTERPRETATION

This study extends the existing empirical evidence linking PCSE to behavioral problems in school-aged children by reporting these effects in a population where tobacco use is normative rather than marginal. Co-exposure to Pb and Hg do not appear to exacerbate tobacco effects, suggesting that these substances act independently.

Short-term behavioral changes in pregnant women after a quit-smoking program via e-learning: a descriptive study from Japan

Approximately 20% of Japanese women in their reproductive years are smokers. Therefore, in the present study, we report the behavioral changes of woman who undertook a 3 month stop-smoking program. Sixty-six pregnant smokers in the first trimester of pregnancy participated in this study from two hospitals and an obstetric clinic in Japan. Our newly-developed e-learning program uses a cell phone Internet connection service to support pregnant women who want to quit smoking. Using this, service participants were given guidance concerning smoking, and were breath tested for their carbon monoxide levels every 4 weeks for 3 months. An e-learning cessation smoking-support program was maintained throughout the same period. Consequently, 52 of 66 pregnant smokers from three settings began the program, and 48 of 52 eventually completed it. The achievement rate of non-smoking was 71.1% (37/48), and their carbon monoxide exhalation levels significantly decreased from 6.43 ± 4.5 ppm at the beginning to 0.7 ± 1.0 ppm in 1 month, to 0.29 ± 1.08 in 3 months (P < 0.001). These results suggest the effectiveness of our e-leaning program. This paper reports the results of the study.

The origins of health and disease: the influence of maternal diseases and lifestyle during gestation

According to the Barker hypothesis, the period of pregnancy and the intrauterine environment are crucial to the tendency to develop diseases like hypertension, diabetes, coronary heart disease, metabolic disorders, pulmonary, renal and mental illnesses. The external environment affects the development of a particular phenotype suitable for an environment with characteristics that closely resemble intrauterine conditions. If the extra-uterine environment differs greatly from the intra-uterine one, the fetus is more prone to develop disease. Subsequent studies have shown that maternal diseases like depression and anxiety, epilepsy, asthma, anemia and metabolic disorders, like diabetes, are able to determine alterations in growth and fetal development. Similarly, the maternal lifestyle, particularly diet, exercise and smoking during pregnancy, have an important role in determining the risk to develop diseases that manifest themselves both during childhood and particularly in adulthood. Finally, there are abundant potential sources of pollutants, both indoor and outdoor, in the environment in which the child lives, which can contribute to an increased probability to the development of several diseases and that in some cases could be easily avoided.

Comprehensive phenotype/genotype analyses of the norepinephrine transporter gene (SLC6A2) in ADHD: relation to maternal smoking during pregnancy

OBJECTIVE

Despite strong pharmacological evidence implicating the norepinephrine transporter in ADHD, genetic studies have yielded largely insignificant results. We tested the association between 30 tag SNPs within the SLC6A2 gene and ADHD, with stratification based on maternal smoking during pregnancy, an environmental factor strongly associated with ADHD.

METHODS

Children (6-12 years old) diagnosed with ADHD according to DSM-IV criteria were comprehensively evaluated with regard to several behavioral and cognitive dimensions of ADHD as well as response to a fixed dose of methylphenidate (MPH) using a double-blind placebo controlled crossover trial. Family-based association tests (FBAT), including categorical and quantitative trait analyses, were conducted in 377 nuclear families.

RESULTS

A highly significant association was observed with rs36021 (and linked SNPs) in the group where mothers smoked during pregnancy. Association was noted with categorical DSM-IV ADHD diagnosis (Z=3.74, P=0.0002), behavioral assessments by parents (CBCL, P=0.00008), as well as restless-impulsive subscale scores on Conners'-teachers (P=0.006) and parents (P=0.006). In this subgroup, significant association was also observed with cognitive deficits, more specifically sustained attention, spatial working memory, planning, and response inhibition. The risk allele was associated with significant improvement of behavior as measured by research staff (Z=3.28, P=0.001), parents (Z=2.62, P=0.009), as well as evaluation in the simulated academic environment (Z=3.58, P=0.0003).

CONCLUSIONS

By using maternal smoking during pregnancy to index a putatively more homogeneous group of ADHD, highly significant associations were observed between tag SNPs within SLC6A2 and ADHD diagnosis, behavioral and cognitive measures relevant to ADHD and response to MPH. This comprehensive phenotype/genotype analysis may help to further understand this complex disorder and improve its treatment. Clinical trial registration information - Clinical and Pharmacogenetic Study of Attention Deficit with Hyperactivity Disorder (ADHD); www.clinicaltrials.gov; NCT00483106.

Longitudinal studies using a "natural experiment" design: the case of adoptees from Romanian institutions

OBJECTIVE

To summarize the advantages and limitations of general population, high-risk and "natural experiment" longitudinal studies for studying psychological change. The English and Romanian Adoptees study is used as an example of a "natural experiment," and detailed findings are provided.

METHOD

What is new is a focus on the young people who spent the whole of their life in institutional care up to the time of adoption and who did not show subnutrition. The results were compared with a composite comparison group who had not experienced institutional care or who were adopted before the age of 6 months. The outcomes were assessed in terms of previously established deprivation-specific patterns (DSPs).

RESULTS

"Pure" psychosocial deprivation was associated with a substantial increase in the rate of DSPs. It was not associated with significantly impaired head growth if institutional care lasted less than 6 months, whereas thereafter there was a 2.5 standard deviation reduction. Subnutrition differed in being accompanied by impaired head and body growth even with institutional care lasting less than 6 months. In the pure psychosocial deprivation group, 45.5% showed a DSP at 15 years compared with 1.3% in the comparison group.

CONCLUSION

"Pure" psychosocial deprivation (in the absence of subnutrition) had a profound effect on psychological functioning in the form of DSPs. Subnutrition had a surprisingly small effect on DSPs.

Maternal smoking during pregnancy and ADHD: a comprehensive clinical and neurocognitive characterization

INTRODUCTION

Evidence from epidemiological studies has consistently shown an association between maternal smoking during pregnancy (MSDP) and attention-deficit/hyperactivity disorder (ADHD). The objective of this study is to test the hypothesis that children with ADHD exposed to MSDP show a distinctive clinical and neurocognitive profile when compared with unexposed children.

METHODS

Four hundred and thirty-six children diagnosed with ADHD were stratified by exposure to MSDP and compared with regard to severity of illness, comorbidity, IQ, and executive function as assessed by a battery of neuropsychological tests. All comparisons were adjusted for socioeconomic status, ethnicity, mother's age at child's birth, and maternal alcohol consumption during pregnancy.

RESULTS

Exposed children had more severe behavioral problems with greater externalizing symptoms and more conduct and oppositional defiant disorder items, lower verbal IQ, and a sluggish cognitive profile on the Continuous Performance Test (CPT). Linear regression analyses revealed a dose-response relationship between the average number of cigarettes smoked per day during pregnancy and verbal IQ, CPT omission errors T score and several other clinical variables.

CONCLUSIONS

These results suggest that MSDP is associated with a more severe form of ADHD, characterized by more severe clinical manifestations and poorer neuropsychological performance. This phenotypic signature associated with MSDP may help to identify a more homogenous subgroup of children with ADHD.

Exposure to environmental and lifestyle factors and attention-deficit / hyperactivity disorder in children — A review of epidemiological studies

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders in children. Although the mechanisms that lead to the development of ADHD remain unclear, genetic and environmental factors have been implicated. These include heavy metals and chemical exposures, nutritional and lifestyle/psychosocial factors. The aim of this review was to investigate the association between ADHD or ADHD-related symptoms and widespread environmental factors such as phthalates, bisphenol A (BPA), tobacco smoke, polycyclic aromatic hydrocarbons (PAHs), polyfluoroalkyl chemicals (PFCs) and alcohol. Medline, PubMed and Ebsco search was performed to identify the studies which analyze the association of prenatal and postnatal child exposure to environmental toxicants and lifestyle factors and ADHD or ADHD-related symptoms. The review is restricted to human studies published since 2000 in English in peer reviewed journals. Despite much research has been done on the association between environmental risk factors and ADHD or ADHD symptoms, results are not consistent. Most studies in this field, focused on exposure to tobacco smoke, found an association between that exposure and ADHD and ADHD symptoms. On the other hand, the impact of phthalates, BPA, PFCs, PAHs and alcohol is less frequently investigated and does not allow a firm conclusion regarding the association with the outcomes of interest.

Relation of prenatal smoking exposure and use of psychotropic medication up to young adulthood

The study objective was to determine the relation of prenatal smoking exposure to the use of psychotropic medication up to young adulthood by using population-based longitudinal register data consisting of all singletons born in Finland from 1987 to 1989 (n = 175,869). Information on maternal smoking was assessed during antenatal care and received from the Finnish Medical Birth Register. Information on the children's psychotropic medication (1994-2007) was received from the Drug Prescription Register, and the children's psychiatric diagnoses related to outpatient (1998-2007) and inpatient (1987-2007) care were derived from the Finnish Hospital Discharge Register. A total of 15.3% (n = 26,083) of the children were exposed to prenatal smoking. The incidence of psychotropic medication use was 8.3% in unexposed children, 11.3% in children exposed to <10 cigarettes per day (adjusted odds ratio = 1.36, 95% confidence interval: 1.29, 1.43), and 13.6% in children exposed to >10 cigarettes per day (odds ratio = 1.63, 95% confidence interval: 1.53, 1.74). The exposure was significantly associated with the risk for all medication use and for both single- and multiple-drug consumption even after adjustment (e.g., mothers' severe psychiatric illnesses). These findings show that exposure to smoking during pregnancy is linked to both mild and severe psychiatric morbidity.

Twin study on transplacental-acquired antibodies and attention deficit/hyperactivity disorder--a pilot study

OBJECTIVE

We hypothesize that maternal transplacentally acquired antibodies may cause Attention Deficit/Hyperactivity Disorder (ADHD) symptoms years after birth, and tested the hypothesis in twins discordant for ADHD symptoms.

METHOD

In a pre-screened sample of 7793 same sex twin pair's (4-18 years) questionnaire data on hyperactivity and inattention was collected. Blood samples taken 5 days after birth from 190 ADHD-score discordant pairs (15% MZ) were analyzed for antibodies.

RESULTS

Pneumococcus Polysaccaride 14 (PnPs14) was present in the ADHD high scoring twin more often than in the lower scoring twin (P=0.04).

CONCLUSION

Although the study provides no strong support for the hypothesis, infection or immunological factors may be one among several causes of ADHD. The genetic control obtained in a twin design may reduce the exposure contrast and a larger sample is needed to further explore the role of PnPs14 in the etiology of ADHD.

Prenatal exposure to perfluorinated chemicals and behavioral or coordination problems at age 7 years

OBJECTIVE

Potential neurotoxic effects of perfluorinated compounds (PFCs) have been reported in highly exposed animals, but whether these chemicals are neurotoxic in humans is not known. We therefore investigated whether prenatal exposure to perfluorooctanoic acid (PFOA) or perfluorooctane sulfate (PFOS), two of the most prevalent PFCs, are associated with behavioral or coordination problems in early childhood.

METHODS

We used data from the Danish National Birth Cohort, which enrolled mothers in early pregnancy, and we measured maternal blood levels of PFOA and PFOS using specimens drawn around 8 weeks of gestation. When the children reached 7 years of age, mothers completed the Strengths and Difficulties Questionnaire (SDQ, n=787) and the Developmental Coordination Disorder Questionnaire (DCDQ, n=526) to assess behavioral health and motor coordination of their children. SDQ scores above the 90th percentile were a priori defined to identify behavioral problems and DCDQ scores below the 10th percentile were defined as a potential DCD.

RESULTS

The median concentrations of PFOS and PFOA in maternal blood were 34.4 ng/mL [interquartile range (IQR), 26.6-44.5] and 5.4 ng/mL (IQR, 4.0-7.1), respectively, similar to distributions reported for populations without occupational exposure. We found no association between higher SDQ scores and maternal levels of PFOS or PFOA, nor did we see any statistically significant association with motor coordination disorders.

CONCLUSION

The findings suggest that background levels of PFOA and PFOS are not associated with behavioral and motor coordination problems in childhood. However, effects on other developmental end points, including cognitive, attentional, and clinical mental disorders not measured in this study, cannot be ruled out.

Maternal smoking and child psychological problems: disentangling causal and noncausal effects

OBJECTIVE

To explore associations of maternal prenatal smoking and child psychological problems and determine the role of causal intrauterine mechanisms.

PATIENTS AND METHODS

Maternal smoking and child psychological problems were explored in 2 birth cohorts in Pelotas, Brazil (n = 509, random subsample), and the Avon Longitudinal Study of Parents and Children (ALSPAC) in Britain (n = 6735). Four approaches for exploring causal mechanisms were applied: (1) cross-population comparisons between a high-income and a middle-income country; (2) multiple adjustment for socioeconomic and parental psychological factors; (3) maternal-paternal comparisons as a test of putative intrauterine effects; and (4) searching for specific effects on different behavioral subscales.

RESULTS

Socioeconomic patterning of maternal prenatal smoking was stronger in the ALSPAC compared with the Pelotas cohort. Despite this difference in a key confounder, consistency in observed associations was found between these cohorts. In both cohorts, unadjusted maternal smoking was associated with greater offspring hyperactivity, conduct/externalizing problems, and peer problems but not with emotional/internalizing problems. After adjusting for confounders and paternal prenatal smoking, only the association with conduct/externalizing problems persisted in both cohorts (conduct problems in the ALSPAC cohort, odds ratio [OR]: 1.24 [95% confidence interval (CI): 1.07-1.46], P = .005; externalizing problems in the Pelotas cohort, OR: 1.82 [95% CI: 1.19-2.78], P = .005; ORs reflect ordinal odds ratios of maternal smokers having offspring with higher scores). Maternal smoking associations were stronger than paternal smoking associations, although statistical evidence that these associations differed was weak in 1 cohort.

CONCLUSION

Evidence from 4 approaches suggests a possible intrauterine effect of maternal smoking on offspring conduct/externalizing problems.

Maternal smoking during pregnancy and regional brain volumes in preterm infants

OBJECTIVE

To evaluate the association between maternal smoking during pregnancy and both brain volumes and head circumference in very-low-birth-weight/very-low-gestational-age infants.

STUDY DESIGN

The PIPARI Study is a prospective follow-up study of infants with a birth weight < or =1500 g or a gestational age <32 weeks born in 2001 to 2006 (n = 232) at Turku University Hospital. The brain was imaged by serial brain ultrasound examinations until discharge and magnetic resonance imaging at term age. The head circumference was measured at birth, term, and 2 years corrected age. These measures were correlated to maternal smoking during pregnancy as reported by the mothers.

RESULTS

The prevalence of maternal smoking was 18%. The frontal lobe (P = .01) and the cerebellar (P = .03) volumes were significantly smaller in the exposed than in the unexposed infants. The volumes of the other parts of the brain did not differ. There was no association between prenatal smoking exposure and head growth or structural brain disease.

CONCLUSIONS

Prenatal smoking exposure was associated with significantly smaller frontal lobe and cerebellar volumes in the brains of preterm infants. This is consistent with reports showing an association between prenatal smoking exposure and impairments in frontal lobe and cerebellar functions such as emotion, impulse control, and attention.