Prenatal and postnatal tobacco exposure and behavioral problems in 10-year-old children: results from the GINI-plus prospective birth cohort study

Systematic Review and Meta-analysis of the Relationship Between Exposure to Parental Substance Use and Attention-Deficit/Hyperactivity Disorder in Children

Attention-deficit/hyperactivity disorder (ADHD) is characterized by persistent patterns of inattention, hyperactivity, and impulsiveness. Among US children and adolescents aged 3-17 years, 9.4% have a diagnosis of ADHD. Previous research suggests possible links between parental substance use and ADHD among children. We conducted a systematic review and meta-analysis of 86 longitudinal or retrospective studies of prenatal or postnatal alcohol, tobacco, or other parental substance use and substance use disorders and childhood ADHD and its related behavioral dimensions of inattention and hyperactivity-impulsivity. Meta-analyses were grouped by drug class and pre- and postnatal periods with combined sample sizes ranging from 789 to 135,732. Prenatal exposure to alcohol or tobacco and parent substance use disorders were consistently and significantly associated with ADHD among children. Other parental drug use exposures resulted in inconsistent or non-significant findings. Prevention and treatment of parental substance use may have potential for impacts on childhood ADHD.

The associations of secondhand smoke exposure with neurodevelopmental disorders and critical time window identification: A systematic review and meta-analysis

BACKGROUND

Secondhand smoke (SHS) exposure was harmful for brain development. However, the association between SHS exposure and NDDs diagnosis were unclear.

OBJECTIVES

To evaluate associations between SHS exposure and NDDs diagnosis, identify critical time windows, and summarize the strength of evidence.

METHODS

To investigate the associations of SHS exposure and the development of NDDs, we searched Ovid, EMBASE, Web of Science, Cochrane Library, and PubMed for all the relevant studies up to 31 March 2023. The risk estimates and standardized mean differences (SMD) for the individuals with any NDDs who were exposed to SHS exposure compared with those unexposed or low-exposed.

RESULTS

The results showed that a total of 31,098 citations were identified, of which 54 studies were included. We identified significant associations between SHS exposure and the risks of NDDs including specific types of NDDs like attention deficit hyperactivity disorder (ADHD) and learning disabilities (LD) despite the observed heterogeneity for NDDs and ADHD. We also observed a significant association between cotinine exposure and ADHD. However, inconsistent ratings between the two quality-of-evidence methods for all the meta-analyses indicated the current evidence of the associations and the potential exposure window remained inconclusive.

DISCUSSION

Our findings suggested that SHS exposure was associated with a higher risk of developing ADHD and LD, with inconclusive quality-of-evidence. In addition, period-specific associations remained unclear based on current evidence.

Associations of timing, level, and pattern of secondhand smoke exposure with early alcohol initiation: A cohort study

BACKGROUND

Few studies explored the longitudinal link between early-life secondhand smoke (SHS) exposure and later alcohol initiation despite its risk for child behavioral difficulties. We examined the associations of the timing, level, and pattern of SHS exposure from pregnancy to childhood with early alcohol initiation and evaluated the sex differences in these associations.

METHODS

Data were from 16,440 participants of the Taiwan Birth Cohort Study conducted when the children were aged 6 months, 18 months, 3 years, 5.5 years, 8 years, and 12 years. Group-based trajectory modeling was applied to identified patterns of SHS exposure. A series of multiple logistic regression were conducted to examine study hypotheses.

RESULTS

Exposure to prenatal SHS was associated with an increased risk of early alcohol initiation (adjusted odds ratio [aOR] = 1.17, 95% confidence interval [CI] = 1.06, 1.30). Compared with the adolescents with a persistent-low-exposure trajectory, those who exhibited prenatal-high-decreasing (aOR = 1.18, 95% CI = 1.04, 1.35) or persistent-high-exposure (aOR = 1.27, 95% CI = 1.12, 1.45) patterns exhibited increased risks of early alcohol initiation. Those with higher cumulative levels of SHS exposure also exhibited an increased risk of early alcohol initiation (aOR = 1.03, 95% CI = 1.01, 1.04). Sex differences were also observed.

CONCLUSIONS

Varying timing, levels, and longitudinal patterns of SHS exposure during early life had differential effects on early alcohol initiation, with the effects differing by sex. Targeting SHS exposure while considering the nature of exposure and sex differences could help prevent and curb alcohol use in adolescents.

Sensitive periods for exposure to indoor air pollutants and psychosocial factors in association with symptoms of psychopathology at school-age in a South African birth cohort

Background

Gestation and the first few months of life are important periods for brain development. During these periods, exposure to environmental toxicants and psychosocial stressors are particularly harmful and may impact brain development. Specifically, exposure to indoor air pollutants (IAP) and psychosocial factors (PF) during these sensitive periods has been shown to predict childhood psychopathology.

Objectives

This study aims to investigate sensitive periods for the individual and joint effects of IAP and PF on childhood psychopathology at 6.5 years.

Methods

We analyzed data from the Drakenstein Child Health Study (N=599), a South African birth cohort. Exposure to IAP and PF was measured during the second trimester of pregnancy and 4 months postpartum. The outcome of childhood psychopathology was assessed at 6.5 years old using the Childhood Behavior Checklist (CBCL). We investigated individual effects of either pre-or postnatal exposure to IAP and PF on CBCL scores using adjusted linear regression models, and joint effects of these exposures using quantile g-computation and self-organizing maps (SOM). To identify possible sensitive periods, we used a structured life course modeling approach (SLCMA) as well as exposure mixture methods (quantile g-computation and SOM).

Results

Prenatal exposure to IAP or PFs, as well as the total prenatal mixture assessed using quantile g-computation, were associated with increased psychopathology. SLCMA and SOM models also indicated that the prenatal period is a sensitive period for IAP exposure on childhood psychopathology. Depression and alcohol were associated in both the pre-and postnatal period, while CO was associated with the postnatal period.

Discussion

Pregnancy may be a sensitive period for the effect of indoor air pollution on childhood psychopathology. Exposure to maternal depression and alcohol in both periods was also associated with psychopathology. Determining sensitive periods of exposure is vital to ensure effective interventions to reduce childhood psychopathology.

Association between postnatal environmental tobacco smoke exposure controlling for prenatal exposure and conduct problems in children: A systematic review

Prenatal exposure to environmental tobacco smoke (ETS) is commonly associated with conduct problems in children. However, there is limited research on the effects of postnatal ETS exposure on the development of conduct problems, and many studies focusing on the postnatal period fail to control for the effects of prenatal ETS. This systematic review explores the association between postnatal ETS exposure and child conduct problems in studies that control for prenatal ETS exposure. Of the thirteen studies identified, nine reported a significant positive association of postnatal ETS exposure and child conduct-related behavior problems when controlling for prenatal ETS exposure. Results from tests of dose-response relationships were mixed. These findings highlight the significance of postnatal ETS exposure in conferring risk for conduct problems over and above prenatal ETS, and thus provide important information for guiding public health recommendations.

Chronic exposure to indoor air pollutants in association with attention-deficit/hyperactivity disorder symptoms in Chinese schoolchildren: A cross-sectional study

BACKGROUND

While increasing studies confirmed the adverse effects of indoor air pollution (IAP) on cardiopulmonary systems, less is known about the impact of IAP on child's brain.

OBJECTIVE

To explore the associations between multiple indoor air pollutants exposures and attention-deficit/hyperactivity disorder (ADHD) symptoms in Chinese schoolchildren.

METHODS

We invited 8630 individuals aged 6-12 years from an ongoing school-based cohort study across Guangzhou from April to May 2019. There are 7495 and 7245 children were respectively evaluated on the parent- and teacher-rated Conner's Rating Scale-Revised, and 7087 children were assessed on both versions. Indoor air pollutants exposures including cooking oil fumes, incense burning, home renovation, and secondhand smoke, were measured using a questionnaire reported by parents and children, and further converted into an index. Generalized linear mixed-effects models were performed to evaluate the associations between indoor air pollutants exposures and ADHD index and the presence of ADHD symptoms.

RESULTS

As reported by parents, 321 (4.3%) children had ADHD symptoms. Each of the four pollutants was positively associated with higher ADHD index and higher odds of ADHD symptoms. Children exposed to 1, 2, and ≥ 3 types of indoor air pollutants had higher ADHD index and higher odds of ADHD symptoms than those non-exposed children. For parent-reported ADHD symptoms, the odds ratios ranged from 1.24 [95% confidence interval (CI): 0.92-1.67] to 2.73 (95% CI: 1.86-4.01). These associations were consistent in parent- and teacher-reported ADHD symptoms, and the combination of both.

CONCLUSION

Indoor air pollutants exposures were positively associated with higher prevalence of children's ADHD symptoms assessed by whether parents or teachers.

Association of Prenatal, Early Postnatal, or Current Exposure to Secondhand Smoke With Attention-Deficit/Hyperactivity Disorder Symptoms in Children

IMPORTANCE

Few studies have investigated the association between the exposure window (prenatal, early postnatal, and current period) of secondhand smoke (SHS) and attention-deficit/hyperactivity disorder (ADHD) symptoms and subtypes in children.

OBJECTIVE

To evaluate the associations of prenatal, early postnatal, or current SHS exposure with ADHD symptoms and subtypes among school-aged children.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, 48 612 children aged 6 to 18 years from elementary and middle schools in Liaoning province, China, between April 2012 and January 2013 were eligible for participation. Data on SHS exposure and ADHD symptoms and subtypes for each child were collected via questionnaires administered to parents or guardians by school teachers. Data were analyzed from September 14 to December 2, 2020.

MAIN OUTCOMES AND MEASURES

The ADHD symptoms and subtypes (inattention, hyperactivity-impulsivity, and combined) were measured based on a validated tool developed from the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition). Generalized linear mixed models were evaluated to estimate the association of SHS exposure with ADHD symptoms and subtypes.

RESULTS

A total of 45 562 participants completed the questionnaires and were included in this study (22 905 girls [50.3%]; mean [SD] age, 11.0 [2.6] years; 2170 [4.8%] with ADHD symptoms). Compared with their unexposed counterparts, children who were ever exposed (odds ratio [OR], 1.50; 95% CI, 1.36-1.66) or always exposed to SHS (OR, 2.88; 95% CI, 2.55-3.25) from pregnancy to childhood had higher odds of having ADHD symptoms and subtypes (ORs ranged from 1.46 [95% CI, 1.31-1.62] to 2.94 [95% CI, 2.09-4.13]). Compared with their unexposed counterparts, children with SHS exposure had higher odds of having ADHD symptoms when exposed in the prenatal period (OR, 2.28; 95% CI, 2.07-2.51), early postnatal period (OR, 1.47; 95% CI, 1.29-1.68), or current period (OR, 1.20; 95% CI, 1.09-1.31). Compared with their unexposed counterparts, children whose fathers smoked 10 or more cigarettes/d on both weekdays and weekends had higher odds of having ADHD symptoms and subtypes (ORs ranged from 1.48 [95% CI, 1.28-1.70] to 2.25 [95% CI, 1.29-3.93]).

CONCLUSIONS AND RELEVANCE

Being exposed to SHS from pregnancy to childhood was associated with higher odds of having ADHD symptoms and subtypes among school-aged children, and the associations were somewhat stronger for SHS exposure during prenatal and early postnatal periods. Our findings highlight the important public health implications of reducing SHS exposure, which may decrease the health and economic burdens of individuals with ADHD.

Exposure to Tobacco Smoke and Temperament among U.S. Children 0-5 Years Old

OBJECTIVES

This study examined the association between tobacco smoke exposure (TSE) and temperament among children 0-5 years old overall and within age groups: 0-2 and 3-5 years.

METHODS

Data were obtained from the 2017-2018 NSCH (N = 14,345). TSE status was defined as whether children lived with a smoker who: does not smoke inside the home (no home TSE) or smokes inside the home (home TSE). We conducted logistic regression analyses while controlling for covariates.

RESULTS

Overall, 12.5% of children lived with a smoker with no home TSE and 1.1% had home TSE. Children with home TSE were at increased odds to not always: be affectionate and tender (aOR = 1.74, 95% CI = 1.18-2.58), show interest and curiosity (aOR = 1.81, 95% CI = 1.23-2.68), and smile and laugh (aOR = 1.77, 95% CI = 1.13-2.77) than those with no TSE. Among 0- to 2-year-olds, those with home TSE were more likely to not always be affectionate and tender (aOR = 1.97, 95% CI = 1.04-3.74). Among 3- to 5-year-olds, those who lived with a smoker with no home TSE were more likely to not always: bounce back quickly (aOR = 1.21, 95% CI = 1.05-1.40) and smile and laugh (aOR = 1.26, 95% CI = 1.03-1.54), and those with home TSE were more likely to not always: show interest and curiosity (aOR = 2.24, 95% CI = 1.40-3.59) and smile and laugh (aOR = 2.43, 95% CI = 1.43-4.11).

CONCLUSIONS

Tobacco smoke-exposed children were at increased odds of not always demonstrating positive early childhood temperament behaviors, with 3- to 5-year-olds having more pronounced odds.

Association between postnatal second-hand smoke exposure and ADHD in children: a systematic review and meta-analysis

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder which is caused by the interplay of genetic and environmental risk factors such as second-hand smoke (SHS). The association between postnatal exposure to SHS and ADHD risk in children was still inconclusive. We performed a systematic review and meta-analysis to explore the definite association. We searched for relevant studies from PubMed, Embase, Ovid, and Web of Science databases up to January 2020. We used random effect models to calculate pooled odds ratio (OR) with 95% confidence interval (CI). Subgroup analyses and sensitive analyses were also performed to solve the heterogeneity. According to our inclusion criteria, 9 studies including 6 cross-sectional studies, 2 cohort studies, and 1 case-control study were included in the final analysis. Postnatal exposure to SHS increased the risk of ADHD in children (OR: 1.60; 95% CI: 1.37-1.87). Children who exposed to SHS were found a slight risk for conduct problems (OR: 1.33, 95% CI: 1.00-1.77). Among the studies which used cotinine as a biomarker for SHS exposure, a lower pooled OR (OR = 1.16, 95%CI = 1.01, 1.33) was observed between cotinine and ADHD in children. Our meta-analysis results suggested that SHS exposure may be a risk factor for ADHD. We also found that SHS exposure may be associated with some adverse behavioral outcomes. More prospective studies should be conducted to confirm the relationship between SHS exposure and ADHD in children.

Longitudinal association between environmental tobacco smoke exposure and behavioral problems in children from ages 5 to 9

Few studies have assessed the cumulative effects of exposure to environmental tobacco smoke (ETS¹) in relation to children's neurobehavioral problems over time. We assessed the longitudinal associations between ETS exposure at age 5 and behavioral problems at ages 5, 7, and 9 using the Ewha Birth and Growth Cohort, in Seoul, Korea. Children with available urinary cotinine levels at age 5 and one or more behavioral problem scores measured with the Korean Version of Child Behavior Checklist (CBCL²) at age 5, 7, and 9 were included in the study. Those whose mothers smoked during pregnancy were excluded, and a total of 179 children were included in the analysis. A linear mixed-model analysis using a REPEATED statement was conducted to assess whether ETS exposure was associated with the total, internalizing, and externalizing behavioral problem scores of the CBCL. The group with higher levels of cotinine showed continuously higher total and external behavioral problem scores from ages 5 to 9, which was seen after adjusting for preterm birth, father's education level, and television watching time. In addition, the difference in the total and external behavioral problem scores between the higher and lower cotinine groups at age 5 was statistically significant after a Bonferroni correction (p = 0.02 and 0.04, respectively), even though the fixed effect of cotinine level was almost but not statistically significant (p = 0.07 and 0.08, respectively). The results of this longitudinal cohort study provide evidence regarding the negative effects of ETS exposure in early childhood and their behavioral problems over time. This study supports the strengthening of anti-smoking policies used in educational interventions for parents, in order to reduce early ETS exposure in children.

Secondhand tobacco smoke, does it have an impact on the neurobehavioral performance of the exposed children?

Secondhand tobacco smoke (SHS) is a significant public health problem for all ages worldwide. Children are more vulnerable to the health effects of SHS because of the inhalation of more air per body volume compared to adults. The study aimed to assess neurobehavioral performance among SHS exposed Egyptian basic school children (10-12 years) and its relationship with urinary cotinine levels. Multistage cluster sampling was carried out, where 181 children (80 exposed and 101 non-exposed children) were recruited. A questionnaire on SHS exposure was sent to students' parents/caregivers. Urine samples were taken for assessment of cotinine levels by enzyme immunoassay. A Neurobehavioral test battery was measured. The exposed children had significantly lower performance in tests of attention (PASAT) [5.22 ± 5.10 vs. 6.98 ± 5.87, p = 0.035], visuomotor speed (Digit Symbol and Trail making A) [41.40 ± 18.01 vs. 46.53 ± 15.89 and 107.92 ± 44.34 vs. 92.44 ± 37.09; respectively] than non-exposed subjects. The neurobehavioral effects were correlated with urinary cotinine levels among children exposed to SHS compared to unexposed children. The study revealed poor performance in neurobehavioral domains of attention and visuomotor skills among children exposed to SHS. This necessitates the implementation of antismoking media awareness programs on the harmful effects of SHS and how to protect children from it.

Fluoride exposure and intelligence in school-age children: evidence from different windows of exposure susceptibility

Background

The intellectual loss induced by fluoride exposure has been extensively studied, but the association between fluoride exposure in different susceptibility windows and children’s intelligence is rarely reported. Hence, we conducted a cross-sectional study to explore the association between fluoride exposure in prenatal and childhood periods and intelligence quotient (IQ).

Methods

We recruited 633 local children aged 7–13 years old randomly from four primary schools in Kaifeng, China in 2017. The children were divided into four groups, of which included: control group (CG, n = 228), only prenatal excessive fluoride exposure group (PFG, n = 107), only childhood excessive fluoride exposure group (CFG, n = 157), both prenatal and childhood excessive fluoride exposure group (BFG, n = 141). The concentrations of urinary fluoride (UF) and urinary creatinine (UCr) were determined by fluoride ion-selective electrode assay and a creatinine assay kit (picric acid method), respectively. The concentration of UCr-adjusted urinary fluoride (CUF) was calculated. IQ score was assessed using the second revision of the Combined Raven’s Test-The Rural in China (CRT-RC2). Threshold and saturation effects analysis, multiple linear regression analysis and logistic regression analysis were conducted to analyze the association between fluoride exposure and IQ.

Results

The mean IQ score in PFG was respectively lower than those in CG, CFG and BFG (P < 0.05). The odds of developing excellent intelligence among children in PFG decreased by 51.1% compared with children in CG (OR = 0.489, 95% CI: 0.279, 0.858). For all the children, CUF concentration of ≥1.7 mg/L was negatively associated with IQ scores (β = − 4.965, 95% CI: − 9.198, − 0.732, P = 0.022). In children without prenatal fluoride exposure, every 1.0 mg/L increment in the CUF concentration of ≥2.1 mg/L was related to a reduction of 11.4 points in children’s IQ scores (95% CI: − 19.2, − 3.5, P = 0.005).

Conclusions

Prenatal and childhood excessive fluoride exposures may impair the intelligence development of school children. Furthermore, children with prenatal fluoride exposure had lower IQ scores than children who were not prenatally exposed; therefore the reduction of IQ scores at higher levels of fluoride exposure in childhood does not become that evident.

Environmental Tobacco Smoke and Educational Self-Regulation and Achievement in First Grade High School Students

Environmental tobacco smoke, containing many toxic gases, suggests inevitable contact of humans with the damaging factors of cigarettes. On average, approximately 40% of children, 35% of women and 32% of men worldwide are exposed to environmental tobacco smoke. This study aims at investigating the relationship between environmental tobacco smoke in adolescents and their educational self-regulation and achievement. In this study, 770 students aged between 13 and 15 were selected and studied using the multistage sampling method. The tools used in this study consisted of four questionnaires, demographic characteristics, environmental tobacco smoke, educational self-regulation, and educational achievement. The validity and reliability of tools have been approved, and the data were analyzed using SPSS v22. The results indicated a significant inverse relationship between environmental tobacco smoke and students' educational self-regulation and achievement (p-value > 0.001). Given the relationship between exposure to environmental tobacco smoke and educational self-regulation and achievement, it is essential to keep children away from tobacco smoke. Family health and education policy-makers are recommended to design and operate fundamental schemes in order to deal with environmental tobacco smoke.

Exposure to Toenail Heavy Metals and Child Behavior Problems in Nine-Year-Old Children: A Cross-Sectional Study

Behavioral problems are multifactorial and includes perinatal, maternal, family, parenting, socio-economic and personal risk factors, but less is known about the association of postnatal heavy metals on children’s behavioral problems in Pacific Island children. Methods: A cohort of eligible nine-year-old children within a Pacific Island Families longitudinal study were recruited for a cross-sectional study. Child behavior problems were assessed using the child behavior checklist. Heavy metals (including Ni, Cu, Pb, Al, Cr and Cd) were determined in toenails, after acid digestion and analyzed using inductively coupled plasma mass spectrometry. Other factors such as lifestyle (smoking in pregnancy), health outcomes (obesity, health status), demographics (gender, ethnicity, parents’ marital status) and socioeconomic status (household income levels) were also collected. The statistical analysis included t-tests for independent sample and Mann–Whitney U-test, and chi-square or Fisher’s exact tests of independence for comparisons of the proportions. Regression models tested the hypothesized risk factors for behavior outcomes. Results: This observational study enrolled 278 eligible Pacific Island children living in Auckland, New Zealand. The prevalence of behavioral problems in the clinical range was high (22%) but there was no significant association between heavy metals in toenails and adverse behavioral outcomes. Conclusion: Regular monitoring and assessments of children for environmental risk factors, as well as social and lifestyle factors for behavior problems, continues. Alternative indicators of exposure to heavy metal should be evaluated.

Associations between Exposure to Tobacco Smoke and Behavioral Problems in Preschool Japanese Children

Background

A few studies related to pediatric behavior have measured secondhand smoke exposure in children using valid objective biochemical markers. We aimed at investigating the associations between current and cumulative exposure to tobacco smoke, measured both subjectively and objectively, and behavioral problems in children.

Methods

Subjects were 437 Japanese children, aged 3–6 years in 2006. Exposure to tobacco smoke was evaluated from a parent-administered questionnaire and urinary cotinine concentrations. The cotinine concentrations were measured using first-void morning urine by liquid chromatography-tandem mass spectrometry. Children's behaviors were assessed by the parent-completed Strengths and Difficulties Questionnaire.

Results

After multiple adjustments for covariates, higher total difficulty scores of children were significantly associated with the larger number of cigarettes parents smoke, more smokers among cohabiters, and more pack-years of exposure to tobacco smoke from parents and cohabiters. The total difficulty scores were 8.72, 9.09, and 10.52, respectively, for children in the low, middle, and high tertiles of creatinine-corrected cotinine concentrations in urine (p=0.002, trend p=0.005). There was no substantial sex difference in the positive associations between passive smoking and the SDQ scores.

Conclusions

Exposure to tobacco smoke in early childhood may be involved in the development of pediatric behavioral problems. The importance of reducing the exposure of children to tobacco smoke, particularly in the home, was further emphasized for the prevention of psychological and behavioral problems in childhood.

Tulve N. A Systematic Review and Meta-Analysis Investigating the Relationship between Exposures to Chemical and Non-Chemical Stressors during Prenatal Development and Childhood Externalizing Behaviors

Childhood behavioral outcomes have been linked to low quality intrauterine environments caused by prenatal exposures to both chemical and non-chemical stressors. The effect(s) from the many stressors a child can be prenatally exposed to may be influenced by complex interactive relationships that are just beginning to be understood. Chemical stressors influence behavioral outcomes by affecting the monoamine oxidase A (MAOA) enzyme, which is involved in serotonin metabolism and the neuroendocrine response to stress. Non-chemical stressors, particularly those associated with violence, have been shown to influence and exacerbate the externalizing behavioral outcomes associated with low MAOA activity and slowed serotonin metabolism. The adverse developmental effects associated with high stress and maternal drug use during pregnancy are well documented. However, research examining the combined effects of other non-chemical and chemical stressors on development and childhood outcomes as a result of gestational exposures is scarce but is an expanding field. In this systematic review, we examined the extant literature to explore the interrelationships between exposures to chemical and non-chemical stressors (specifically stressful/traumatic experiences), MAOA characteristics, and childhood externalizing behaviors. We observed that exposures to chemical stressors (recreational drugs and environmental chemicals) are significantly related to externalizing behavioral outcomes in children. We also observed that existing literature examining the interactions between MAOA characteristics, exposures to chemical stressors, and traumatic experiences and their effects on behavioral outcomes is sparse. We propose that maternal stress and cortisol fluctuations during pregnancy may be an avenue to link these concepts. We recommend that future studies investigating childhood behaviors include chemical and non-chemical stressors as well as children’s inherent genetic characteristics to gain a holistic understanding of the relationship between prenatal exposures and childhood behavioral outcomes.

Secondhand smoke as a risk factor for attention deficit hyperactivity disorder in children

Background: Attention deficit hyperactivity disorder (ADHD) is recognized as a common childhood psychiatric disorder‏ with a worldwide prevalence estimated at 5%. In Egypt, early exposure of children to smoke occurred due to many causes mainly tobacco use. This exposure is linked to a variety of developmental and behavioral consequences for children. This study aimed to investigate the potential association between secondhand smoke (SHS) exposure and ADHD in children and find the association between the level of exposure to SHS and the degree of ADHD symptoms.Method: Case-control study was done by a random selection of children from the outpatient Clinic of Assiut University Hospital of Children. Data were collected by a questionnaire to evaluate home exposure to SHS and blood sampling for serum cotinine measurement as an indicator of exposure to SHS.Results: Of 70 ADHD children, 62 (88.6%) of them reported home exposure to smoke while only 14 of 30 control children (46.7%) reported home exposure to smoke. The serum cotinine level was insignificantly higher in the ADHD group than the control group.Conclusion: In conclusion, there is a significant association between ADHD in the examined sample of children and exposure to SHS. Serum cotinine is a biomarker reflecting current exposure to SHS but it is not a reliable indicator of past and long-term exposure to SHS.

The association between exposure to secondhand smoke and psychological symptoms among Chinese children

Background

The effect of secondhand smoke (SHS) exposure on child psychological problems remained inconclusive in previous studies. The aim of this study is to explore the association between SHS exposure and psychological symptoms in children.

Methods

This population-based cross-sectional survey used cluster random probability sampling and recruited children aged 6–13 years in 26 primary schools in Shanghai, China, in 2014. Duration of SHS exposure in children were categorized as none, < 1 h/day, 1–2 h/day, ≥3 h/day. Psychological symptoms were assessed by the parental version of the Strengths and Difficulties Questionnaire (SDQ). We used logistic regression to estimate the adjusted associations of SHS exposure with total SDQ and its specific domains. Multiple imputation was used for handling missing data.

Results

A total of 17,571 children completed this survey, with a response rate of 99.7%. SDQ scores were available for 15,344 participants, of whom 20.9% were not exposed to SHS, 63.0% exposed for < 1 h/day, 10.4% for 1–2 h/day, and 5.7% for ≥3 h/day. Compared to children not exposed to SHS, SHS exposure was positively associated with total SDQ score: OR 1.42, 95% confidence interval (CI) 1.22 to 1.66 for SHS exposure < 1 h/day, OR 2.14, 95% CI 1.76 to 2.62 for 1–2 h/day and OR 2.53, 95% CI 2.01 to 3.18 for ≥3 h/day after adjusting for sex, age, mode of birth, family socio-economic status and place of birth. These associations did not vary by sex.

Conclusion

SHS exposure is an independent risk factor for psychological problems among children. Nonetheless, our study is unable to distinguish between fetal and child exposure to SHS.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7006-8) contains supplementary material, which is available to authorized users.

Relation Between Oppositional/Conduct Behaviors and Executive Function Among Youth with Histories of Heavy Prenatal Alcohol Exposure

BACKGROUND

Youth with heavy prenatal alcohol exposure have high rates of behavioral concerns and psychopathology, including increased oppositional and conduct behaviors. The relation between those concerns and executive function (EF) deficits is unknown. We investigated the association of oppositional and conduct behavior and EF in adolescents to inform targeted intervention.

METHODS

Subjects (N = 267) ages 10 to 17 years comprised 3 groups: alcohol-exposed with oppositional/conduct behaviors (AE+), alcohol-exposed without oppositional/conduct behaviors (AE-), and controls (CON). Group differences on direct neuropsychological (Delis-Kaplan Executive Function System [D-KEFS]) and indirect parent-report (Behavior Rating Inventory of Executive Function [BRIEF]) EF measures were tested with multivariate analysis of covariances, followed by univariate analysis of variances and pairwise comparisons. The contribution of attention-deficit/hyperactivity disorder (ADHD) within the AE groups was assessed in secondary analyses.

RESULTS

On the D-KEFS, there was an omnibus main effect of group, with significant main effects on 3 of 6 variables (CON>AE+, AE-). Within the AE groups, ADHD did not alter the results. On the BRIEF, there was an omnibus significant main effect of group, with significant main effects on all scales (CON<AE-<AE+). Within the AE groups, the AE+ group had higher BRIEF scores (i.e., more difficulty) than the AE- group on 4 of 8 subscales when accounting for presence of ADHD.

CONCLUSIONS

EF deficits in youth with histories of prenatal alcohol exposure were confirmed using direct and indirect measures. Oppositional/conduct behaviors related to EF deficits on indirect but not direct EF measures. Greater understanding of the contribution of concurrent psychopathology to long-term outcomes for alcohol-exposed youth requires further investigation.

Two Lifestyle Risks Intertwined: Parental Smoking Predicts Child Gambling Behavior at Age 12 Years

BACKGROUND

Parental smoking can create a toxic environment for child development. A parental smoking lifestyle can predispose children to executive deficits, influencing precocious risk activities. Using a prospective birth cohort design, we examine the association between 2 lifestyle factors by estimating the relative contribution of long-term parental household smoking in predicting subsequent precocious child gambling behavior.

METHOD

Parents reported on the amount of household smoke exposure from ages 1.5 to 7.5 years for children from the Quebec Longitudinal Study of Child Development. The main outcome measure was children's self-report of gambling behavior (at age 12 years).

RESULTS

Sixty percent of parents reported that their children were never exposed to secondhand smoke in the home, while 27% and 13% reported transient and continuous levels of secondhand smoke, respectively. Overall, 16% of children reported gambling participation. When compared with never-exposed children, children exposed to secondhand smoke had 18% more chances of having participated in gambling at age 12 years (odds ratio = 1.18; 95% CI = 1.080-1.293). These results are adjusted for competing explanations and possible individual and family confounders.

CONCLUSIONS

Higher levels of early childhood household smoke exposure are associated with greater odds of reporting gambling participation at age 12 years, which is more than several years before it is normative youthful behavior. By connecting the neurotoxic influence of one lifestyle factor on another, we show a nontrivial link between 2 public health issues (smoke exposure and precocious gambling) associated with considerable individual and societal costs that are amenable to community information campaigns.

The link between parental smoking and youth externalizing behaviors: Effects of smoking, psychosocial factors, and family characteristics

This study examined the associations between parental cigarette smoking and youth externalizing behaviors (i.e., oppositional and conduct problems) both concurrently and 1 year later, and tested whether parental smoking predicted youth externalizing over and above parent psychosocial, family, and demographic characteristics linked to smoking and externalizing behaviors. Data were drawn from the Seattle Social Development Project (SSDP) and The Intergenerational Project (TIP), a prospective longitudinal study aimed toward understanding the intergenerational transmission of substance use, mental health, and risky behaviors. The current study used multilevel modeling to examine both concurrent and lagged associations from 325 families, which included parents and youth (Aged 6-19) across seven waves of data. In concurrent analyses, both parental smoking and several family characteristics independently predicted higher levels of child externalizing behaviors, even after controlling for parent age at child birth and demographic correlates of smoking. However, parental depressive symptoms reduced the association between smoking and externalizing behaviors to nonsignificance in concurrent models. In lagged analyses, only harsh parenting, low monitoring, and low parent-child bonding predicted externalizing behaviors 1 year later; parental smoking did not predict externalizing behaviors over time. Results showed that parental smoking, mental health, parenting, and family relationships all are associated with externalizing problems and constitute potential intervention targets in the short term, though poor parenting and parent-child bonding, rather than smoking, predicted externalizing behaviors over time. The robust association between concurrent parental depressive symptoms and youth conduct problems may suggest prioritizing parental mental health (e.g., via mental health screening) for improving both parent and child well-being. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Early childhood exposure to secondhand smoke and behavioural problems in preschoolers

Evidence on behavioural abnormalities in children exposed to secondhand smoke is limited. This study examined the relation between infant/ toddler cotinine concentration, a biomarker of secondhand smoke exposure, and behavioural problems in preschoolers who were unexposed to maternal smoking during gestation. A prospective cohort of 301 non-smoking mothers with their young children aged ≤18 months visiting postnatal primary care clinics in Hong Kong was enrolled in 2012 and followed by telephone survey 3 years afterwards. Saliva was collected at baseline for cotinine assay. Child behavioural health at 3-year follow-up was assessed by the parent-reported Strengths and Difficulties Questionnaire (SDQ). We conducted multivariable linear regressions to compute regression coefficients (b) of SDQ scores in relation to salivary cotinine level. Mean ± SD age of children at follow-up was 3.7 ± 0.5 years and 50.8% were boys. After adjusting for age, sex, birthweight, household income, housing type, maternal education and depressive symptoms, greater cotinine concentrations during early childhood were associated with greater conduct problems (b = 0.90, 95% CI 0.03-1.76) and hyperactivity/ inattention (b = 1.12, 95% CI 0.07-2.17) at preschool age. This study corroborates previous findings on the potential role of secondhand smoke in development of child behavioural problems.

Associations between urinary cotinine and symptoms of attention deficit/hyperactivity disorder and autism spectrum disorder

BACKGROUND

The present study investigated associations between urinary cotinine levels as a biomarker of secondhand smoke exposure and symptoms of attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).

METHODS

A total of 520 child participants (200 with ADHD, 67 with ASD, and 253 normal control subjects) were assessed using the Korean version of the ADHD rating scale (K-ARS), Autism spectrum screening questionnaire (ASSQ), and Behavioral Assessment System for Children, second edition (BASC-2). The Korean version of the computer-based continuous performance test was used to assess cognitive function. Urinary cotinine was evaluated as a biomarker of secondhand smoke exposure.

RESULTS

Urinary cotinine levels were significantly and positively associated with K-ARS score (B = 4.00, p < 0.001), ASSQ score (B = 1.71, p = 0.030), the behavioral problem subscales of the BASC-2 (B = 1.68-3.52, p < 0.001-0.045), and omission and commission errors in the continuous performance test (B = 6.21-8.42, p < 0.001-0.019). Urinary cotinine levels were also associated with the increased odds ratio of ADHD (OR = 1.55, 95% CI 1.05-2.30, p = 0.028) and ASD (OR = 1.89, 95% CI 1.12-3.21, p = 0.018).

CONCLUSION

Urinary cotinine levels were associated with lower behavioral adaptation and cognitive function and increased odds ratios of ADHD and ASD, indicating a negative effect of secondhand smoke exposure on the symptomatic manifestation of ADHD and ASD.

The impact of pre- and perinatal factors on psychopathology in adulthood

BACKGROUND

There is considerable evidence that pre- and post-natal factors are associated with a wide range of psychopathology in offspring during childhood and adolescence.

OBJECTIVE

The main aims of the present study were to examine the associations between pre- and perinatal factors and psychopathology in offspring during adulthood, and to explore whether family factors (i.e., family cohesion, mother's social support, and father's social support) mediate these relationships.

METHOD

Information on pre- and perinatal events was collected from biological mothers of the participants (N = 315) when they were between 14 and 18 years who were then followed up until they reached age 30.

RESULTS

Maternal obstetric history and illness during first year were significant predictors of offspring anxiety disorder. Maternal emotional health predicted offspring affective disorder. Difficult delivery and breast feeding predicted disruptive disorder. The relationship between maternal obstetric history/emotional health and anxiety/affective disorder was no longer significant after controlling for family cohesion.

LIMITATIONS

The information was based on maternal recall when their offspring were between 14 and 18 years which may be subjected to recall bias.

CONCLUSION

The association between pre- and postnatal factors and psychopathology of offspring during adulthood is mediated by familial factors.

Exposure to Environmental Tobacco Smoke in Relation to Behavioral, Emotional, Social and Health Indicators of Slovak School Children

Environmental tobacco smoke (ETS) exposure has been shown in general as a major environmental risk factor and deserves attention in vulnerable population groups. The aim of the project is to analyze the relationships among the ETS and behavior and health in 6−15-year-old children in Slovakia. The status of physical and mental health of children in relation to exposure to tobacco smoke was examined in a representative group of 1478 school children. The methods used, included anonymous questionnaires filled in by parents, Columbia Impairment Scale (CIS), Behavior Problem Index (BPI) and anthropometry. The prevalence of ETS exposure is the highest in the capital (27%) and southern cities. A significant association was found between ETS and age, socio-economic status, incompleteness of the family, level of mother’s education and a higher prevalence of respiratory diseases (26.7%). The relationships of ETS with emotional (CIS scores ≥ 16) and behavioral functions (BPI score ≥ 14) were significant in children exposed to mother’s or father’s smoking at home. In the multivariate analysis these associations were not significant; the factors such as income and completeness of the family were dominant. The results showed mostly the predominant impact of social factors on the physical and mental health status of Slovak school children.

Self-Reported Environmental Tobacco Smoke Exposure and Avoidance Compared with Cotinine Confirmed Tobacco Smoke Exposure among Pregnant Women and Their Infants

BACKGROUND

Exposure to environmental tobacco smoke (ETS) presents substantial health risks for pregnant women and newborn infants. Measurements of ETS include invasive and expensive biochemical tests, as well as less invasive and lower-cost, self-reported exposure and avoidance measures. Better understanding of self-report measures will help to select ETS assessments for evaluation.

METHODS

This analysis was conducted within the context of a tailored video intervention to reduce tobacco smoking and ETS exposure during pregnancy and after delivery in the control group sample of 147 nonsmoking women. Measurements of salivary cotinine concentration, self-reported ETS exposure, and avoidance behaviors were captured at 32 weeks’ gestation and 6 months postpartum.

RESULTS

Salivary cotinine concentration was significantly related to ETS avoidance among pregnant nonsmokers at 32 weeks’ gestation, but not ETS exposure. At 6 months postpartum, both the reported ETS exposure of the infant and maternal avoidance behaviors to reduce her infant’s exposure were associated with the infant’s salivary cotinine concentration. At 32 weeks’ gestation and 6 months postpartum, avoidance behaviors decreased as exposure increased.

DISCUSSION

This study suggests that for nonsmoking women during pregnancy, reports of tobacco smoke avoidance are more valid than reports of exposure. After delivery, self-reported ETS exposure or avoidance are associated with each other and the biochemical measurement of salivary cotinine. These results provide researchers and clinicians with evidence to support the inclusion of avoidance behaviors in the selection of ETS measures.

Maternal Smoking in Pregnancy and Offspring Depression: a cross cohort and negative control study

Previous reports suggest that offspring of mothers who smoke during pregnancy have greater risk of developing depression. However, it is unclear whether this is due to intrauterine effects. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) from the UK (N = 2,869), the Nord-Trøndelag health study (HUNT) from Norway (N = 15,493), the Pelotas 1982 Birth Cohort Study from Brazil (N = 2,626), and the Swedish Sibling Health Cohort (N = 258 sibling pairs), we compared associations of maternal smoking during pregnancy and mother’s partner’s smoking during pregnancy with offspring depression and performed a discordant sibling analysis. In meta-analysis, maternal smoking during pregnancy was associated with higher odds of offspring depression (OR 1.20, 95% CI:1.08,1.34), but mother’s partner’s smoking during pregnancy was not (OR 1.05, 95% CI:0.94,1.17). However, there was only weak statistical evidence that the odds ratios for maternal and mother’s partner’s smoking differed from each other (p = 0.08). There was no clear evidence for an association between maternal smoking during pregnancy and offspring depression in the sibling analysis. Findings do not provide strong support for a causal role of maternal smoking during pregnancy in offspring depression, rather observed associations may reflect residual confounding relating to characteristics of parents who smoke.

Prenatal Exposure to Environmental Tobacco Smoke and Hyperactivity Behavior in Chinese Young Children

This study aimed to examine the association between prenatal environmental tobacco smoke (ETS) exposure and hyperactivity behaviors in young children. A cross-sectional study was undertaken among 21,243 participants from all of the kindergartens in Longhua District of Shenzhen, China. Multivariate logistic regression models and hierarchical linear models were employed to assess the associations. After adjusting for potential confounders of gender, preterm birth, birth asphyxiation, etc., prenatal ETS exposure was significantly associated with an increased risk of hyperactivity behaviors in young children (OR (95% CI) = 1.51 (1.28-1.77); β (95% CI) = 0.017 (0.013-0.020)). Along with increases in children's prenatal ETS exposure dose (measured by daily ETS exposure duration, daily cigarette consumption by household members, and overall score of prenatal ETS exposure), the children were also increasingly more likely to exhibit hyperactivity behaviors. Furthermore, children whose mothers had prenatal ETS exposure in any one or more of the pregnancy trimesters were more likely to exhibit hyperactivity behaviors as compared with those born to non-exposure mothers (all p < 0.05). Overall, prenatal ETS exposure could be associated with a detrimental impact on offspring's hyperactivity behaviors, and public health efforts are needed to reduce prenatal ETS exposure.

Prospective longitudinal associations between household smoke exposure in early childhood and antisocial behavior at age 12

Young children exert little control over household tobacco smoke exposure, which is considered a developmental neurotoxicant. Using the Quebec Longitudinal Study birth cohort, we examine prospective associations between early childhood smoke exposure and later antisocial behavior. Parents of 1035 children reported on the presence of household smokers at seven follow-ups from ages 1.5 to 7.5. At age 12, children self-reported on five aspects of early antisocial dispositions. After adjusting for confounders, every standard deviation increase in household smoke exposure was prospectively associated with a 19% standard deviation unit increase in conduct problems (β=0.07; 95% confidence interval [CI] from 0.04 to 0.09), a 11% standard deviation unit increase in proactive aggression (β=0.04; 95% CI from 0.01 to 0.07), a 13% standard deviation unit increase in reactive aggression (β=0.07; 95% CI from 0.03 to 0.12), a 14% standard deviation unit increase in school indiscipline (β=0.13; 95% CI from 0.05 to 0.20), and a 10% standard deviation unit increase in dropout risk (β=0.07; 95% CI from 0.01 to 0.12). These long-term findings warrant fostering parental awareness of developmental risks by policy-makers/health practitioners. School curricula can equally integrate these ideas into their curriculum.

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.

Testing Causal Effects of Maternal Smoking During Pregnancy on Offspring's Externalizing and Internalizing Behavior

Maternal smoking during pregnancy (SDP) is associated with increased risk of externalizing and internalizing behaviors in offspring. Two explanations (not mutually exclusive) for this association are direct causal effects of maternal SDP and the effects of genetic and environmental factors common to parents and offspring which increase smoking as well as problem behaviors. Here, we examined the associations between parental SDP and mother rated offspring externalizing and internalizing behaviors (rated by the Child Behavior Checklist/2-3) at age three in a population-based sample of Dutch twins (N = 15,228 pairs). First, as a greater effect of maternal than of paternal SDP is consistent with a causal effect of maternal SDP, we compared the effects of maternal and paternal SDP. Second, as a beneficial effect of quitting smoking before pregnancy is consistent with the causal effect, we compared the effects of SDP in mothers who quit smoking before pregnancy, and mothers who continued to smoke during pregnancy. All mothers were established smokers before their pregnancy. The results indicated a greater effect of maternal SDP, compared to paternal SDP, for externalizing, aggression, overactive and withdrawn behavior. Quitting smoking was associated with less externalizing, overactive behavior, aggression, and oppositional behavior, but had no effect on internalizing, anxious depression, or withdrawn behavior. We conclude that these results are consistent with a causal, but small, effect of smoking on externalizing problems at age 3. The results do not support a causal effect of maternal SDP on internalizing behaviors.

Postnatal Environmental Tobacco Smoke Exposure Related to Behavioral Problems in Children

Objective

The purpose of this study was to examine the association between pre and post environmental tobacco smoke (ETS) exposure and behavioral problems in schoolchildren.

Methods

In the cross-sectional 6 cities Study conducted in France, 5221 primary school children were investigated. Pre- and postnatal exposure to secondhand tobacco smoke at home was assessed using a parent questionnaire. Child’s behavioral outcomes (emotional symptoms and conduct problems) were evaluated by the Strengths and Difficulties Questionnaire (SDQ) completed by the parents.

Results

ETS exposure during the postnatal period and during both pre- and postnatal periods was associated with behavioral problems in children. Abnormal emotional symptoms (internalizing problems) were related to ETS exposure in children who were exposed during the pre- and postnatal periods with an OR of 1.72 (95% Confidence Interval (CI)= 1.36-2.17), whereas the OR was estimated to be 1.38 (95% CI= 1.12-1.69) in the case of postnatal exposure only. Abnormal conduct problems (externalizing problems) were related to ETS exposure in children who were exposed during the pre- and postnatal periods with an OR of 1.94 (95% CI= 1.51-2.50), whereas the OR was estimated to be 1.47 (95% CI=1.17-1.84) in the case of postnatal exposure only. Effect estimates were adjusted for gender, study center, ethnic origin, child age, low parental education, current physician diagnosed asthma, siblings, preterm birth and single parenthood.

Conclusion

Postnatal ETS exposure, alone or in association with prenatal exposure, increases the risk of behavioral problems in school-age children.

The health burden of pollution: the impact of prenatal exposure to air pollutants

Exposure to atmospheric pollutants in both open and closed environments is a major cause of morbidity and mortality that may be both controlled and minimized. Despite growing evidence, several controversies and disagreements exist among the studies that have analyzed the effects of prenatal pollutant exposure. This review article aims to analyze primary scientific evidence of the effects of air pollution during pregnancy and the impact of these effects on the fetus, infant health, and in particular, the respiratory system. We performed a review of articles from the PubMed and Web of Science databases that were published in English within the past 5 years, particularly those related to birth cohorts that began in pregnancy with follow-up until the first years of life. The largest reported effects are associated with prenatal exposure to particulate matter, nitrogen dioxide, and tobacco smoke. The primary effects affect birth weight and other parameters of fetal biometry. There is strong evidence regarding the impact of pollutants on morbidity secondary to respiratory problems. Growing evidence links maternal smoking to childhood asthma and wheezing. The role of passive maternal smoking is less clear. Great heterogeneity exists among studies. There is a need for additional studies on birth cohorts to monitor the relationship between the exposure of pregnant women to pollutants and their children’s progress during the first years of life.

Exposure to secondhand smoke in the home and mental health in children: a population-based study

OBJECTIVES

To examine the association between exposure to secondhand smoke (SHS) in the home and mental health among children.

METHODS

Cross-sectional study of 2357 children representative of the Spanish population aged 4-12 years in 2011-2012. Duration of SHS exposure in children was reported by parents. Probable mental disorder was defined as a score>90th centile in the parental version of the Strengths and Difficulties Questionnaire (SDQ). Statistical analysis was performed with logistic regression and adjusted for sociodemographic variables, lifestyle, neighbourhood environment and family characteristics, including parental mental health.

RESULTS

Among study participants, 6.9% (95% CI 5.7% to 8.0%) were exposed to SHS in the home for <1 h/day and 4.5% (95% CI 3.5% to 5.5%) for ≥1 h/day. Compared to children not habitually exposed to SHS, the multivariate ORs for probable mental disorder were 1.49 (95% CI 0.85 to 2.62) for SHS exposure<1 h/day and 2.73 (95% CI 1.38 to 5.41) for SHS exposure≥1 h/day (p for linear trend=0.002). The corresponding ORs for attention-deficit and hyperactivity disorder (ADHD) were 2.18 (95% CI 1.30 to 3.64) for <1 h/day exposure and 3.14 (95% CI 1.63 to 6.04) for ≥1 h/day exposure (p for linear trend<0.001). No association was found between SHS and the rest of the components of the SDQ.

CONCLUSIONS

Among children, SHS exposure in the home during ≥1 h/day is associated with a higher frequency of mental disorder. This association was mostly due to the impact of SHS on ADHD.

Developmental consequences of fetal exposure to drugs: what we know and what we still must learn

Most drugs of abuse easily cross the placenta and can affect fetal brain development. In utero exposures to drugs thus can have long-lasting implications for brain structure and function. These effects on the developing nervous system, before homeostatic regulatory mechanisms are properly calibrated, often differ from their effects on mature systems. In this review, we describe current knowledge on how alcohol, nicotine, cocaine, amphetamine, Ecstasy, and opiates (among other drugs) produce alterations in neurodevelopmental trajectory. We focus both on animal models and available clinical and imaging data from cross-sectional and longitudinal human studies. Early studies of fetal exposures focused on classic teratological methods that are insufficient for revealing more subtle effects that are nevertheless very behaviorally relevant. Modern mechanistic approaches have informed us greatly as to how to potentially ameliorate the induced deficits in brain formation and function, but conclude that better delineation of sensitive periods, dose-response relationships, and long-term longitudinal studies assessing future risk of offspring to exhibit learning disabilities, mental health disorders, and limited neural adaptations are crucial to limit the societal impact of these exposures.

Environmental tobacco smoke in the early postnatal period induces impairment in brain myelination

Environmental tobacco smoke (ETS) is associated with high morbidity and mortality, mainly in children. However, few studies focus on the brain development effects of ETS exposure. Myelination mainly occurs in the early years of life in humans and the first three postnatal weeks in rodents and is sensitive to xenobiotics exposure. This study investigated the effects of early postnatal ETS exposure on myelination. BALB/c mice were exposed to ETS generated from 3R4F reference research cigarettes from the third to the fourteenth days of life. The myelination of nerve fibers in the optic nerve by morphometric analysis and the levels of Olig1 and myelin basic protein (MBP) were evaluated in the cerebellum, diencephalon, telencephalon, and brainstem in infancy, adolescence, and adulthood. Infant mice exposed to ETS showed a decrease in the percentage of myelinated fibers in the optic nerve, compared with controls. ETS induced a decrease in Olig1 protein levels in the cerebellum and brainstem and an increase in MBP levels in the cerebellum at infant. It was also found a decrease in MBP levels in the telencephalon and brainstem at adolescence and in the cerebellum and diencephalon at adulthood. The present study demonstrates that exposure to ETS, in a critical phase of development, affects the percentage of myelinated fibers and myelin-specific proteins in infant mice. Although we did not observe differences in the morphological analysis in adolescence and adulthood, there was a decrease in MBP levels in distinctive brain regions suggesting a delayed effect in adolescence and adulthood.

Physical, behavioral, and cognitive effects of prenatal tobacco and postnatal secondhand smoke exposure

The purpose of this review is to examine the rapidly expanding literature regarding the effects of prenatal tobacco and postnatal secondhand smoke (SHS) exposure on child health and development. Mechanisms of SHS exposure are reviewed, including critical periods during which exposure to tobacco products appears to be particularly harmful to the developing fetus and child. The biological, biochemical, and neurologic effects of the small fraction of identified components of SHS are described. Research describing these adverse effects of both in utero and childhood exposure is reviewed, including findings from both animal models and humans. The following adverse physical outcomes are discussed: sudden infant death syndrome, low birth weight, decreased head circumference, respiratory infections, otitis media, asthma, childhood cancer, hearing loss, dental caries, and the metabolic syndrome. In addition, the association between the following adverse cognitive and behavioral outcomes and such exposures is described: conduct disorder, attention-deficit/hyperactivity disorder, poor academic achievement, and cognitive impairment. The evidence supporting the adverse effects of SHS exposure is extensive yet rapidly expanding due to improving technology and increased awareness of this profound public health problem. The growing use of alternative tobacco products, such as hookahs (a.k.a. waterpipes), and the scant literature on possible effects from prenatal and secondhand smoke exposure from these products are also discussed. A review of the current knowledge of this important subject has implications for future research as well as public policy and clinical practice.

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.

Early life programming as a target for prevention of child and adolescent mental disorders

This paper concerns future policy development and programs of research for the prevention of mental disorders based on research emerging from fetal and early life programming. The current review offers an overview of findings on pregnancy exposures such as maternal mental health, lifestyle factors, and potential teratogenic and neurotoxic exposures on child outcomes. Outcomes of interest are common child and adolescent mental disorders including hyperactive, behavioral and emotional disorders. This literature suggests that the preconception and perinatal periods offer important opportunities for the prevention of deleterious fetal exposures. As such, the perinatal period is a critical period where future mental health prevention efforts should be focused and prevention models developed. Interventions grounded in evidence-based recommendations for the perinatal period could take the form of public health, universal and more targeted interventions. If successful, such interventions are likely to have lifelong effects on (mental) health.

Development of BMI values of German children and their healthcare costs

The aim of this study is to assess the association between different patterns of Body Mass Index (BMI) development from birth on and later healthcare utilisation and costs in children aged about 10 years based on two birth cohort studies: the GINIplus study (3287 respondents) and the LISAplus study (1762 respondents). Direct costs were estimated using information on healthcare utilisation given by parents in the 10-year follow-up. To meet this aim, we (i) estimate BMI-standard deviation score (BMIZ) trajectories using latent growth mixture models and (ii) examine the correlation between these trajectories and utilisation of healthcare services and resulting costs at the 10-year follow-up. We identified three BMI-trajectories: a normative BMIZ growth class (BMI development almost as in the WHO growth standards), a rapid BMIZ growth up to age 2 years class (with a higher BMI in the first two years of life as proposed by the WHO growth standards) and a persistent rapid BMIZ growth up to age 5 years class (with a higher BMI in the first five years of life as proposed by the WHO growth standards). Annual total direct medical costs of healthcare use are estimated to be on average €368 per child. These costs are doubled, i.e. on average €722 per child, in the group with the most pronounced growth (persistent rapid BMIZ growth up to age 5 years class).

Prenatal nicotine exposure and child behavioural problems

In utero exposure to tobacco smoke has been related to numerous adverse health effects in new-borns, infants, children, adolescents and adults. The aim of this review was to summarise findings on prenatal nicotine exposure and its relationship with behavioural problems in the offspring. The majority of studies, and especially several recent epidemiological studies, observed a higher likelihood for attention-deficit/hyperactivity disorder (ADHD) or ADHD symptoms in exposed subjects. However, both human and animal studies have failed to provide clear evidence on causality. Existing literature on studies investigating the association between prenatal nicotine exposure and conduct or externalising problems in the offspring suggests a causal effect. The establishment of a final conclusion concerning the relationship between prenatal nicotine exposure and internalising problems in the offspring is complicated by insufficient data and mixed results in epidemiological studies. Prenatal nicotine exposure has been associated with altered brain structure and function in human offspring, and a proposed biological mechanism is related to nicotine's adverse influence on neurotransmitter systems during brain development. In conclusion, establishing a statement on the causality of the relationship between prenatal nicotine exposure and behavioural problems in children remains a challenging task. Nevertheless, considering the results of an increasing number of studies which link prenatal exposure to nicotine to externalising problems applying different methodologies to account for confounding and in view of other adverse health effects known to be caused by this exposure, parents should consider smoking cessation.

Prenatal exposure to environmental contaminants and behavioural problems at age 7-8years

Animal studies showed that the developing brain is particularly sensitive to chemical exposure. Human studies carried out in areas with high exposures have proven neurodevelopmental disorders in relation to e.g. lead and PCBs. Whether these chemicals are associated with behavioural problems in childhood at current environmental levels is not well known. Therefore, we assessed the association between prenatal exposure to lead, cadmium, PCBs, dioxin-like compounds, HCB and p,p'-DDE and behavioural problems in 7-8year old children. Prenatal exposure data were obtained from the Flemish mother-new-born cohort. Lead, cadmium, PCBs, dioxin-like compounds, HCB and p,p'-DDE were analysed in cord blood. When the child reached 7-8years, 270 mothers completed the Strengths and Difficulties Questionnaire assessing their children's behavioural health. We found that doubling the prenatal lead exposure (cord blood lead levels) was associated with a 3.43 times higher risk for hyperactivity in both boys and girls. In addition, total difficulties were 5.08 times more likely in the highest tertile for prenatal lead exposure compared to the lowest tertile. In girls, total difficulties were 4.92 more likely when doubling cord blood p,p'-DDE, whereas no significant association was found in boys. Further, we noted in boys a 1.53 times higher risk for emotional problems when doubling cord blood cadmium, whereas no significant association was found in girls. These results indicate that the presence of environmental contaminants influences the mental health of the next generation.

Housing and child health

The connection between housing and health is well established. Physical, chemical, and biological aspects of the child's home, such as cleanliness, moisture, pests, noise, accessibility, injury risks, and other forms of housing environmental quality, all have the potential to influence multiple aspects of the health and development of children. Basic sanitation, reduced household crowding, other improvements in housing and expanded, and improved housing regulations have led to advances in children's health. For example, lead poisoning prevention policies have profoundly reduced childhood lead exposure in the United States. This and many other successes highlight the health benefits for families, particularly children, by targeting interventions that reduce or eliminate harmful exposures in the home. Additionally, parental mental health problems, food insecurity, domestic violence, and the presence of guns in children's homes all are largely experienced by children in their homes, which are not as yet considered part of the Healthy Homes agenda. There is a large movement and now a regulatory structure being put in place for healthy housing, which is becoming closely wedded with environmental health, public health, and the practice of pediatrics. The importance of homes in children's lives, history of healthy homes, asthma, and exposures to lead, carbon monoxide, secondhand/thirdhand smoke, radon, allergy triggers is discussed, as well as how changes in ambient temperature, increased humidity, poor ventilation, water quality, infectious diseases, housing structure, guns, electronic media, family structure, and domestic violence all affect children's health.

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.