Maternal prepregnancy body mass index and offspring attention-deficit/hyperactivity disorder: a quasi-experimental sibling-comparison, population-based design

Maternal gestational weight gain and offspring's neurodevelopmental outcomes: A systematic review and meta-analysis

Abnormal gestational weight gain (GWG) has been increasing globally, up to 47% of all pregnancies. Multiple studies have focused on the association between GWG and adverse neurodevelopmental outcomes in the offspring, however with inconsistent results. We performed a systematic review and meta-analysis to evaluate associations between excessive or insufficient GWG and offspring's neurodevelopmental outcomes. Meta-analysis of these 23 studies using a random-effects model revealed associations between excessive GWG and neurodevelopmental disorders (ASD & ID & ADHD together: OR=1.12 [95% CI 1.06-1.19]), ASD (OR=1.18 [95% CI 1.08-1.29]), ADHD (OR=1.08 [95% CI 1.02-1.14]), ASD with ID (OR=1.15 [95% CI 1.01-1.32]), and ASD without ID (OR=1.12 [95% CI 1.06-1.19]). Insufficient GWG was associated with higher risk for ID (OR=1.14 [95% CI 1.03-1.26]). These results emphasize the significant impact, though of small effect size, of GWG across multiple neurodevelopmental disorders. It is important to note that these results do not establish causality. Other factors such as genetic factors, gene-environment interactions may confound the relationship between GWG and neurodevelopmental outcomes. To better understand the role of GWG in neurodevelopmental disorders, future studies should consider using genetically sensitive designs that can account for these potential confounders.

Maternal pre-pregnancy BMI and offspring hyperactivity-inattention trajectories from 3 to 8 years in the EDEN birth cohort study

Evidence suggests obesity during pregnancy is associated with offspring attention-deficit hyperactivity disorder. However, studies have been limited to evaluating the association at a single age with inadequate data on important maternal lifestyle confounders and unmeasured familial confounding. The objective of this study was to examine the association between maternal pre-pregnancy body mass index (BMI) and child hyperactivity-inattention symptoms (HIS) at 3, 5 and 8 years. Data came from the EDEN mother-child cohort. Maternal pre-pregnancy BMI status (kg/m2) was calculated using pre-pregnancy weight and height (self-reported by mothers or measured by midwives). HIS were assessed by parental-report on the Strengths and Difficulties Questionnaire at 3, 5 and 8 years of age and used to derive developmental trajectories of HIS (n = 1428). Multivariate models were adjusted for confounders including socioeconomic status, maternal lifestyle behaviours (exercise, diet, smoking, alcohol), childcare and a stimulating home environment. Paternal BMI was used as a negative control. Compared to a normal pre-pregnancy BMI, pre-pregnancy maternal obesity was positively associated with increased odds of a high HIS trajectory between 3 and 8 years old in both unadjusted and adjusted logistic regression (adjusted odds ratio [aOR] 1.87 [95% CI 1.12, 3.12]). Pre-pregnancy overweight was not significantly associated after adjustment for confounders (aOR 1.32 [0.87, 2.01]). Maternal pre-pregnancy obesity, but not overweight, was associated with increased likelihood of a high HIS trajectory in children from 3 to 8 years old. This association persisted despite controlling for many important maternal lifestyle factors and paternal BMI. Further research is warranted to identify possible mediators involved.

Annual Research Review: Perspectives on progress in ADHD science - from characterization to cause

The science of attention-deficit/hyperactivity disorder (ADHD) is motivated by a translational goal - the discovery and exploitation of knowledge about the nature of ADHD to the benefit of those individuals whose lives it affects. Over the past fifty years, scientific research has made enormous strides in characterizing the ADHD condition and in understanding its correlates and causes. However, the translation of these scientific insights into clinical benefits has been limited. In this review, we provide a selective and focused survey of the scientific field of ADHD, providing our personal perspectives on what constitutes the scientific consensus, important new leads to be highlighted, and the key outstanding questions to be addressed going forward. We cover two broad domains - clinical characterization and, risk factors, causal processes and neuro-biological pathways. Part one focuses on the developmental course of ADHD, co-occurring characteristics and conditions, and the functional impact of living with ADHD - including impairment, quality of life, and stigma. In part two, we explore genetic and environmental influences and putative mediating brain processes. In the final section, we reflect on the future of the ADHD construct in the light of cross-cutting scientific themes and recent conceptual reformulations that cast ADHD traits as part of a broader spectrum of neurodivergence.

Maternal pre-pregnancy obesity and offspring hyperactivity-inattention symptoms at 5 years in preterm and term children: a multi-cohort analysis

The objective of this study was to determine the relationship between maternal pre-pregnancy body mass index (BMI) and child hyperactivity-inattention symptoms (HIS) at 5 years, including preterm and term-born children, and to determine whether this association varied with gestational age. Maternal pre-pregnancy BMI and offspring HIS were assessed in 10,898 participants born ≥ 33 weeks of gestation from the ELFE cohort and 2646 children born between 23 and 34 weeks from the EPIPAGE 2 cohort. Reported pre-pregnancy weight (kg) and measured height (m) were collected from mothers at inclusion and used to classify BMI (kg/m²). Child HIS were evaluated using the Strengths and Difficulties Questionnaire around 5 years of age. Logistic regression estimated odds ratios (OR) of a high HIS score (≥ 90th percentile) in the ELFE cohort and generalized estimated equations were used in EPIPAGE 2 to account for non-independence of multiple births. As a negative control, paternal BMI was also considered as an exposure of interest in sensitivity analyses. Maternal pre-pregnancy obesity and overweight were associated with child HIS at 5 years in ELFE (adjusted OR [aOR] for obesity 1.27 [1.06, 1.53]; overweight aOR 1.16 [1.00, 1.36]) and pre-pregnancy obesity was associated with high HIS scores in preterm infants of EPIPAGE 2 (aOR 1.48 [1.06, 2.08]). In ELFE, the magnitude of the association increased with decreasing gestational age (interaction p = 0.02). High maternal pre-pregnancy BMI is associated with greater likelihood of high HIS scores in both at-term and preterm children at 5 years of age.

The Influence of Maternal Metabolic State and Nutrition on Offspring Neurobehavioral Development: A Focus on Preclinical Models

The prevalence of both obesity and neurodevelopmental disorders has increased substantially over the last several decades. Early environmental factors, including maternal nutrition and metabolic state during gestation, influence offspring neurodevelopment. Both human and preclinical models demonstrate a link between poor maternal nutrition, altered metabolic state, and risk of behavioral abnormalities in offspring. This review aims to highlight evidence from the current literature connecting maternal nutrition and the associated metabolic changes with neural and behavioral outcomes in the offspring, as well as identify possible mechanisms underlying these neurodevelopmental outcomes. Owing to the highly correlated nature of poor nutrition and obesity in humans, preclinical animal models are important in distinguishing the unique effects of maternal nutrition and metabolic state on offspring brain development. We use a translational lens to highlight results from preclinical animal models of maternal obesogenic diet related to alterations in behavioral and neurodevelopmental outcomes in offspring. Specifically, we aim to highlight results that resemble behavioral phenotypes described in the diagnostic criteria of neurodevelopmental conditions in humans. Finally, we examine the proinflammatory nature of maternal obesity and consumption of a high-fat diet as a mechanism for neurodevelopmental alterations that may alter offspring behavior later in life. It is important that future studies examine potential therapeutic interventions and prevention strategies to interrupt the transgenerational transmission of the disease. Given the tremendous risk to the next generation, changes need to be made to ensure that all pregnant people have access to nutritious food and are informed about the optimal diet for their developing child.

Pre-pregnancy body mass index and parent and teacher-reported behavioral outcomes among offspring in childhood

OBJECTIVE

Pre-pregnancy obesity has been linked to childhood neurodevelopmental outcomes, including autism and attention-deficit hyperactivity disorder. The aim of our study was to examine the association between pre-pregnancy body mass index (BMI) and scores on behavioral scales according to both mother and teacher report.

METHODS

We conducted a longitudinal study of 469 mother-child pairs. Information on pre-pregnancy body mass index (BMI) was collected from standardized maternal interviews conducted after delivery and assessment of childhood behavioral problems was measured at 5-12 years of age according to maternal-report using the Child Behavior Checklist (CBCL) and teacher-report using the Teacher Report Form (TRF). Using normal pre-pregnancy BMI (18.5-24.9 kg/m²) as the reference (n = 305), we calculated adjusted mean differences (MD) for t-scores on broadband and syndrome scales of behavior for children of mothers with pre-pregnancy overweight (n = 101) or obese (n = 63) BMI. We also examined associations with scores in the clinical range using risk ratios (RR) and compared results across informants. To account for loss to follow-up between the initial interview and the childhood behavioral assessment, we weighted models using stabilized inverse probability weights.

RESULTS

Pre-pregnancy obesity was associated with a mean increase in child's total behavior problem t-scores according to both mother and teacher report, after adjustment for confounders and weighted for loss to follow-up (MD: 0.7, 95% CI: -2.2, 3.6 on CBCL; MD: 3.1, 95% CI: 0.5, 5.7 on TRF), indicating poorer behavioral outcomes. Comparing the magnitude of associations between mother and teacher-report, mean differences for pre-pregnancy obesity and most behavioral problem scales were larger for teacher-reported outcomes than mother-reported outcomes. Pre-pregnancy obesity was associated with increased risks of externalizing behaviors in the clinical range regardless of informant (CBCL RR: 1.6, 95% CI: 0.8, 3.2 and TRF RR: 1.7, 95% CI: 0.8, 3.5). Pre-pregnancy obesity was also associated with increased risks of internalizing behaviors according to teacher-report (TRF RR: 2.6, 95% CI:1.5, 4.6).

CONCLUSIONS

Pre-pregnancy obesity, compared to pre-pregnancy normal weight, is associated with generally higher scores on both mother and teacher reported childhood behavioral assessments, indicating an increased likelihood of behavioral problems.

Role of Maternal Microbiota and Nutrition in Early-Life Neurodevelopmental Disorders

The rise in the prevalence of obesity and other related metabolic diseases has been paralleled by an increase in the frequency of neurodevelopmental problems, which has raised the likelihood of a link between these two phenomena. In this scenario, maternal microbiota is a possible linking mechanistic pathway. According to the “Developmental Origins of Health and Disease” paradigm, environmental exposures (in utero and early life) can permanently alter the body’s structure, physiology, and metabolism, increasing illness risk and/or speeding up disease progression in offspring, adults, and even generations. Nutritional exposure during early developmental stages may induce susceptibility to the later development of human diseases via interactions in the microbiome, including alterations in brain function and behavior of offspring, as explained by the gut–brain axis theory. This review provides an overview of the implications of maternal nutrition on neurodevelopmental disorders and the establishment and maturation of gut microbiota in the offspring.

Maternal body mass index in pregnancy and mental disorders in adult offspring: a record linkage study in Aberdeen, Scotland

Maternal obesity in pregnancy predicts offspring psychopathology risk in childhood but it remains unclear whether maternal obesity or underweight associate with adult offspring mental disorders. We examined longitudinally whether maternal body mass index (BMI) in pregnancy predicted mental disorders in her offspring and whether the associations differed by offspring birth year among 68,571 mother–child dyads of Aberdeen Maternity and Neonatal Databank, Scotland. The offspring were born 1950–1999. Maternal BMI was measured at a mean 15.7 gestational weeks and classified into underweight, normal weight, overweight, moderate obesity and severe obesity. Mental disorders were identified from nationwide registers carrying diagnoses of all hospitalizations and deaths in Scotland in 1996–2017. We found that maternal BMI in pregnancy was associated with offspring mental disorders in a time-dependent manner: In offspring born 1950–1974, maternal underweight predicted an increased hazard of mental disorders [Hazard Ratio (HR) = 1.74; 95% Confidence Interval (CI) = 1.01–3.00)]. In offspring born 1975–1999, maternal severe obesity predicted increased hazards of any mental (HR 1.60; 95% CI 1.08–2.38) substance use (HR 1.91; 95% CI 1.03–3.57) and schizophrenia spectrum (HR 2.80; 95% CI 1.40–5.63) disorders. Our findings of time-specific associations between maternal prenatal BMI and adult offspring mental disorders may carry important public health implications by underlining possible lifelong effects of maternal BMI on offspring psychopathology.

Association of maternal diabetes with neurodevelopmental disorders: autism spectrum disorders, attention-deficit/hyperactivity disorder and intellectual disability

Background

Maternal diabetes has been associated with a risk of neurodevelopmental disorders (NDDs) in offspring, though the common co-occurrence of autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder (ADHD) and intellectual disability (ID) is rarely considered, nor is the potential for confounding by shared familial factors (e.g. genetics).

Methods

This population-based cohort study used data from Psychiatry Sweden, a linkage of Swedish national registers, to follow 2 369 680 individuals born from 1987 to 2010. We used population-averaged logit models to examine the association between exposure to maternal type 1 diabetes mellitus (T1DM), pre-gestational type 2 diabetes mellitus (T2DM) or gestational diabetes mellitus (GDM), and odds of NDDs in offspring. Subgroup analysis was then performed to investigate the timings of GDM diagnosis during pregnancy and its effect on the odds of NDDs in offspring. We compared these results to models considering paternal lifetime T1DM and T2DM as exposures.

Results

Overall, 45 678 individuals (1.93%) were diagnosed with ASD, 20 823 (0.88%) with ID and 102 018 (4.31%) with ADHD. All types of maternal diabetes were associated with odds of NDDs, with T2DM most strongly associated with any diagnosis of ASD (odds ratio_adjusted 1.37, 95% confidence interval 1.03–1.84), ID (2.09, 1.53–2.87) and ADHD (1.43, 1.16–1.77). Considering common co-morbid groups, the associations were strongest between maternal diabetes and diagnostic combinations that included ID. Paternal T1DM and T2DM diagnoses were also associated with offspring NDDs, but these associations were weaker than those with maternal diabetes. Diagnosis of GDM between 27 and 30 weeks of gestation was generally associated with the greatest risk of NDDs in offspring, with the strongest associations for outcomes that included ID.

Conclusion

The association of maternal diabetes with NDDs in offspring varies depending on the co-morbid presentation of the NDDs, with the greatest odds associated with outcomes that included ID. Results of paternal-comparison studies suggest that the above associations are likely to be partly confounded by shared familial factors, such as genetic liability.

Maternal pre-pregnancy overweight/obesity and the risk of attention-deficit/hyperactivity disorder in offspring: a systematic review, meta-analysis and quasi-experimental family-based study

BACKGROUND

Previous studies are inconclusive concerning the association between maternal pre-pregnancy overweight/obesity and risk of attention-deficit/hyperactivity disorder (ADHD) in offspring. We therefore conducted a systematic review and meta-analysis to clarify this association. To address the variation in confounding adjustment between studies, especially inadequate adjustment of unmeasured familial confounding in most studies, we further performed cousin and sibling comparisons in a nationwide population-based cohort in Sweden.

METHODS

We searched PubMed, Embase and PsycINFO during 1975-2018. We used random-effects models to calculate pooled risk ratios (RRs) with 95% confidence interval. In the population-based study, Cox proportional hazard models were used to calculate the unadjusted hazard ratios (HRs) and HRs adjusted for all confounders identified in previous studies. Stratified Cox models were applied to data on full cousins and full siblings to further control for unmeasured familial confounding.

RESULTS

Eight cohorts with a total of 784 804 mother-child pairs were included in the meta-analysis. Maternal overweight [RRoverweight = 1.31 (1.25-1.38), I2 = 6.80%] and obesity [RRobesity = 1.92 (1.84-2.00), I2 = 0.00%] were both associated with an increased risk of ADHD in offspring. In the population-based cohort of 971 501 individuals born between 1992 and 2004, unadjusted Cox models revealed similar associations [HRoverweight = 1.30 (1.28-1.34), HRobesity = 1.92 (1.87-1.98)]. These associations gradually attenuated towards the null when adjusted for measured confounders [HRoverweight = 1.21 (1.19-1.25), HRobesity = 1.60 (1.55-1.65)], unmeasured factors shared by cousins [HRoverweight = 1.10 (0.98-1.23), HRobesity = 1.44 (1.22-1.70)] and unmeasured factors shared by siblings [HRoverweight = 1.01 (0.92-1.11), HRobesity = 1.10 (0.94-1.27)].

CONCLUSION

Pre-pregnancy overweight/obesity is associated with an increased risk of ADHD in offspring. The observed association is largely due to unmeasured familial confounding.

Development of ADHD: Etiology, Heterogeneity, and Early Life Course

ADHD represents a powerful entry point for developmental approaches to psychopathology due to its major role in early emergence of major life problems. One key issue concerns the role of early environmental risks in etiology and maintenance in the context of genetic liability. Here, psychosocial aspects of development need more attention. A second key issue is that phenotypic heterogeneity requires better resolution if actionable causal mechanisms are to be effectively identified. Here, the interplay of cognition and emotion in the context of a temperament lens is one helpful way forward. A third key issue is the poorly understood yet somewhat striking bifurcation of developmental course in adolescence, when a subgroup seem to have largely benign outcomes, while a larger group continue on a problematic path. A final integrative question concerns the most effective conceptualization of the disorder in relation to broader dysregulation. Key scientific priorities are noted.

Development of ADHD: Etiology, Heterogeneity, and Early Life Course

ADHD represents a powerful entry point for developmental approaches to psychopathology due to its major role in early emergence of major life problems. One key issue concerns the role of early environmental risks in etiology and maintenance in the context of genetic liability. Here, psychosocial aspects of development need more attention. A second key issue is that phenotypic heterogeneity requires better resolution if actionable causal mechanisms are to be effectively identified. Here, the interplay of cognition and emotion in the context of a temperament lens is one helpful way forward. A third key issue is the poorly understood yet somewhat striking bifurcation of developmental course in adolescence, when a subgroup seem to have largely benign outcomes, while a larger group continue on a problematic path. A final integrative question concerns the most effective conceptualization of the disorder in relation to broader dysregulation. Key scientific priorities are noted.

Environmental risk factors, protective factors, and peripheral biomarkers for ADHD: an umbrella review

BACKGROUND

Many potential environmental risk factors, environmental protective factors, and peripheral biomarkers for ADHD have been investigated, but the consistency and magnitude of their effects are unclear. We aimed to systematically appraise the published evidence of association between potential risk factors, protective factors, or peripheral biomarkers, and ADHD.

METHODS

In this umbrella review of meta-analyses, we searched PubMed including MEDLINE, Embase, and the Cochrane Database of Systematic Reviews, from database inception to Oct 31, 2019, and screened the references of relevant articles. We included systematic reviews that provided meta-analyses of observational studies that examined associations of potential environmental risk factors, environmental protective factors, or peripheral biomarkers with diagnosis of ADHD. We included meta-analyses that used categorical ADHD diagnosis criteria according to DSM, hyperkinetic disorder according to ICD, or criteria that were less rigorous than DSM or ICD, such as self-report. We excluded articles that did not examine environmental risk factors, environmental protective factors, or peripheral biomarkers of ADHD; articles that did not include a meta-analysis; and articles that did not present enough data for re-analysis. We excluded non-human studies, primary studies, genetic studies, and conference abstracts. We calculated summary effect estimates (odds ratio [OR], relative risk [RR], weighted mean difference [WMD], Cohen's d, and Hedges' g), 95% CI, heterogeneity I² statistic, 95% prediction interval, small study effects, and excess significance biases. We did analyses under credibility ceilings, and assessed the quality of the meta-analyses with AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews 2). This study is registered with PROSPERO, number CRD42019145032.

FINDINGS

We identified 1839 articles, of which 35 were eligible for inclusion. These 35 articles yielded 63 meta-analyses encompassing 40 environmental risk factors and environmental protective factors (median cases 16 850, median population 91 954) and 23 peripheral biomarkers (median cases 175, median controls 187). Evidence of association was convincing (class I) for maternal pre-pregnancy obesity (OR 1·63, 95% CI 1·49 to 1·77), childhood eczema (1·31, 1·20 to 1·44), hypertensive disorders during pregnancy (1·29, 1·22 to 1·36), pre-eclampsia (1·28, 1·21 to 1·35), and maternal acetaminophen exposure during pregnancy (RR 1·25, 95% CI 1·17 to 1·34). Evidence of association was highly suggestive (class II) for maternal smoking during pregnancy (OR 1·6, 95% CI 1·45 to 1·76), childhood asthma (1·51, 1·4 to 1·63), maternal pre-pregnancy overweight (1·28, 1·21 to 1·35), and serum vitamin D (WMD -6·93, 95% CI -9·34 to -4·51).

INTERPRETATION

Maternal pre-pregnancy obesity and overweight; pre-eclampsia, hypertension, acetaminophen exposure, and smoking during pregnancy; and childhood atopic diseases were strongly associated with ADHD. Previous familial studies suggest that maternal pre-pregnancy obesity, overweight, and smoking during pregnancy are confounded by familial or genetic factors, and further high-quality studies are therefore required to establish causality.

FUNDING

None.

Early environmental risk factors for neurodevelopmental disorders - a systematic review of twin and sibling studies

While neurodevelopmental disorders (NDDs) are highly heritable, several environmental risk factors have also been suggested. However, the role of familial confounding is unclear. To shed more light on this, we reviewed the evidence from twin and sibling studies. A systematic review was performed on case control and cohort studies including a twin or sibling within-pair comparison of neurodevelopmental outcomes, with environmental exposures until the sixth birthday. From 7,315 screened abstracts, 140 eligible articles were identified. After adjustment for familial confounding advanced paternal age, low birth weight, birth defects, and perinatal hypoxia and respiratory stress were associated with autism spectrum disorder (ASD), and low birth weight, gestational age and family income were associated with attention-deficit/hyperactivity disorder (ADHD), categorically and dimensionally. Several previously suspected factors, including pregnancy-related factors, were deemed due to familial confounding. Most studies were conducted in North America and Scandinavia, pointing to a global research bias. Moreover, most studies focused on ASD and ADHD. This genetically informed review showed evidence for a range of environmental factors of potential casual significance in NDDs, but also points to a critical need of more genetically informed studies of good quality in the quest of the environmental causes of NDDs.

Relationship of prenatal maternal obesity and diabetes to offspring neurodevelopmental and psychiatric disorders: a narrative review

Obesity and diabetes is a worldwide public health problem among women of reproductive age. This narrative review highlights recent epidemiological studies regarding associations of maternal obesity and diabetes with neurodevelopmental and psychiatric disorders in offspring, and provides an overview of plausible underlying mechanisms and challenges for future human studies. A comprehensive search strategy selected terms that corresponded to the domains of interest (maternal obesity, different types of diabetes, offspring cognitive functions and neuropsychiatric disorders). The databases searched for articles published between January 2010 and April 2019 were PubMed, Web of Science and CINAHL. Evidence from epidemiological studies strongly suggests that maternal pre-pregnancy obesity is associated with increased risks for autism spectrum disorder, attention-deficit hyperactivity disorder and cognitive dysfunction with modest effect sizes, and that maternal diabetes is associated with the risk of the former two disorders. The influence of maternal obesity on other psychiatric disorders is less well studied, but there are reports of associations with increased risks for offspring depression, anxiety, schizophrenia and eating disorders, at modest effect sizes. It remains unclear whether these associations are due to intrauterine mechanisms or explained by confounding family-based sociodemographic, lifestyle and genetic factors. The plausible underlying mechanisms have been explored primarily in animal models, and are yet to be further investigated in human studies.

Fetal brain and placental programming in maternal obesity: A review of human and animal model studies

Both human epidemiologic and animal model studies demonstrate that prenatal and lactational exposure to maternal obesity and high-fat diet are associated with adverse neurodevelopmental outcomes in offspring. Neurodevelopmental outcomes described in offspring of obese women include cognitive impairment, autism spectrum disorder (ASD), attention deficit hyperactivity disorder, anxiety and depression, disordered eating, and propensity for reward-driven behavior, among others. This review synthesizes human and animal data linking maternal obesity and high-fat diet consumption to abnormal fetal brain development, and neurodevelopmental and psychiatric morbidity in offspring. It highlights key mechanisms by which maternal obesity and maternal diet impact fetal and offspring development, and sex differences in offspring programming. In addition, we review placental effects of maternal obesity, and the role the placenta might play as an indicator vs mediator of fetal programming.

Parental Weight Status and Offspring Behavioral Problems and Psychiatric Symptoms

OBJECTIVES

To assess relations of prepregnancy maternal and paternal obesity with offspring behavioral problems and psychiatric symptoms at 7-8 years in the Upstate KIDS study, a prospective cohort study.

STUDY DESIGN

Maternal body mass index (BMI) was calculated from prepregnancy height and weight provided in vital records or self-report at 4 months postpartum. Mothers reported paternal height and weight. At 7-8 years, mothers indicated if their children had been diagnosed with ADHD or anxiety (n = 1915). Additionally, children's behavior was measured with the Strengths and Difficulties Questionnaire at 7 years of age (n = 1386) and the Vanderbilt ADHD Diagnostic Parent Rating Scale at 8 years of age (n = 1484). Based on Strengths and Difficulties Questionnaire scores, we identified children with borderline behavioral problems. Adjusted risk ratios (aRR) and 95% CIs were estimated with robust multivariable Poisson regression.

RESULTS

Compared with children of mothers with a BMI of <25, children whose mothers had BMI 25-30, 30-35, and ≥35 kg/m2 had higher risks of reported ADHD (aRR, 1.14, 95% CI, 0.78-1.69; aRR, 1.96, 95% CI, 1.29-2.98; and aRR, 1.82, 95% CI,1.21-2.74, respectively). Risks of hyperactivity problems identified by the Strengths and Difficulties Questionnaire and a positive screen for inattentive or hyperactive/impulsive behavior with the Vanderbilt ADHD Diagnostic Parent Rating Scale were also higher with increasing maternal prepregnancy BMI. Paternal BMI was not associated with child outcomes.

CONCLUSIONS

Our findings suggest that maternal, rather than paternal, obesity is associated with maternal report of child ADHD diagnosis and inattentive or hyperactivity problems. Further research is needed to understand how maternal obesity might influence these behavioral changes during or after pregnancy.

Sex differences in the association between prenatal exposure to maternal obesity and hippocampal volume in children

INTRODUCTION

Animal studies have shown that male but not female offspring exposed to maternal obesity have abnormal hippocampal development. Similar sex differences were observed in animal models of developmental programming by prenatal stress or maternal diabetes. We aimed to translate this work into humans by examining sex-specific effects of exposure to maternal obesity on hippocampal volume in children.

METHODS

Eighty-eight children (37 boys and 51 girls) aged 7-11 years completed the study. Maternal prepregnancy body mass index (BMI) was obtained from electronic medical records. A high-resolution anatomical scan was performed using a 3-Tesla magnetic resonance imaging (MRI) scanner. Total hippocampal volume and hippocampal subfield volumes were analyzed using FreeSurfer 6.0. Linear regression was used to investigate sex differences in relationships between maternal prepregnancy BMI and child hippocampal volume.

RESULTS

Maternal prepregnancy BMI ranged from 19.0 to 50.4 kg/m² . We observed a significant interaction between maternal prepregnancy BMI and sex on total hippocampal volume (p < .001) such that boys (r = -.39, p = .018) but not girls (r = .11, p = .45) had a significant negative relationship between maternal prepregnancy BMI and total hippocampal volume. This relationship in boys remained significant after adjusting for child and maternal covariates (β = -126.98, p = .012). The sex interactions with prepregnancy BMI were consistently observed in hippocampal subfields CA1 (p = .008), CA2/3 (p = .016), CA4 (p = .002), dentate gyrus (p < .001), and subiculum (p < .001).

CONCLUSIONS

Our results support findings in animal models and suggest that boys may be more vulnerable to the adverse effects of exposure to maternal obesity on hippocampal development than girls.

Addressing Discrepancies Between ADHD Prevalence and Case Identification Estimates Among U.S. Children Utilizing NSCH 2007-2012

Objective: Among U.S. children, ADHD epidemiological estimates (3%-5%) vary significantly from case identification rates (over 11%), leading to confusion about true incidence and prevalence. We investigated the extent to which this discrepancy could be resolved by definitional issues through reexamining the most cited U.S. survey of case identification, the National Survey of Children's Health (NSCH). Method: Using NSCH 2007/2008 and 2011/2012, we stratified identification of ADHD by current status, severity, psychiatric comorbidity, and ADHD medication usage. Using those criteria, definitional strength was coded into "Definite," "Probable," "Doubtful," and "No." Results: "Definite" ADHD in caseness in 2007/2008 was 4.04%, increasing to 5.49% in 2011/2012, roughly corresponding to epidemiological estimates. "Definite" ADHD was the primary contributor to an overall increase in caseness over that period. Conclusion: This analysis strengthens understanding of discrepancies in estimated ADHD rates. When low confidence identification is considered false positives, ADHD case identification rates match epidemiological estimates more closely.

Pre-Pregnancy Weight and Symptoms of Attention Deficit Hyperactivity Disorder and Executive Functioning Behaviors in Preschool Children

This study examines pre-pregnancy Body Mass Index (BMI) and gestational weight gain (GWG) in relation to early childhood Attention Deficit Hyperactivity Disorder (ADHD) symptoms and related executive self-regulation behaviors. The analyses sample (n = 331) included a subsample of participants from a birth cohort recruited from prenatal clinics and hospital facilities from April 2005 to June 2011 in Durham, North Carolina. Pre-pregnancy BMI was calculated from weight at the last menstrual period and height was extracted from medical records. Gestational weight gain was calculated from pre-pregnancy weight and weight measured at the time of delivery. ADHD symptoms and executive self-regulation behaviors were assessed by maternal report (mean age = 3 years). Multivariable regression methods with inverse probability weighting (IPW) were used to evaluate associations accounting for sample selection bias and confounding. Pre-pregnancy BMI at levels ≥35 was positively associated with higher ADHD symptoms and worse executive self-regulation behaviors (inhibitory control and attention). Compared to adequate GWG, less than adequate GWG was related to more ADHD hyperactive-impulsive symptoms, whereas greater than adequate GWG was related to more problematic behaviors related to working memory and planning. The findings support a link between maternal weight and child neurodevelopment. Continued research that help identify biological mechanisms are needed.

Maternal pre-pregnancy obesity and child neurodevelopmental outcomes: a meta-analysis

This review examined evidence of the association between maternal pre-pregnancy overweight/obesity status and child neurodevelopmental outcomes. PubMed and PsycINFO databases were systematically searched for empirical studies published before April 2017 using keywords related to prenatal obesity and children's neurodevelopment. Of 1483 identified papers, 41 were included in the systematic review, and 32 articles representing 36 cohorts were included in the meta-analysis. Findings indicated that compared with children of normal weight mothers, children whose mothers were overweight or obese prior to pregnancy were at increased risk for compromised neurodevelopmental outcomes (overweight: OR = 1.17, 95% CI [1.11, 1.24], I²  = 65.51; obese: OR = 1.51; 95% CI [1.35, 1.69], I²  = 79.63). Pre-pregnancy obesity increased the risk of attention deficit-hyperactivity disorder (OR = 1.62; 95% CI [1.23, 2.14], I²  = 70.15), autism spectrum disorder (OR = 1.36; 95% CI [1.08, 1.70], I²  = 60.52), developmental delay (OR = 1.58; 95% CI [1.39, 1.79], I²  = 75.77) and emotional/behavioural problems (OR = 1.42; 95% CI [1.26, 1.59], I²  = 87.74). Given the current obesity prevalence among young adults and women of childbearing age, this association between maternal obesity during pregnancy and atypical child neurodevelopment represents a potentially high public health burden.