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Exposure to certain chemicals prenatally and in childhood can impact development and may increase risk for attention-deficit/hyperactivity disorder (ADHD). Leveraging a larger set of literature searches conducted to synthesize results from longitudinal studies of potentially modifiable risk factors for childhood ADHD, we present meta-analytic results from 66 studies that examined the associations between early chemical exposures and later ADHD diagnosis or symptoms. Studies were eligible for inclusion if the chemical exposure occurred at least 6 months prior to measurement of ADHD diagnosis or symptomatology. Included papers were published between 1975 and 2019 on exposure to anesthetics (n = 5), cadmium (n = 3), hexachlorobenzene (n = 4), lead (n = 22), mercury (n = 12), organophosphates (n = 7), and polychlorinated biphenyls (n = 13). Analyses are presented for each chemical exposure by type of ADHD outcome reported (categorical vs. continuous), type of ADHD measurement (overall measures of ADHD, ADHD symptoms only, ADHD diagnosis only, inattention only, hyperactivity/impulsivity only), and timing of exposure (prenatal vs. childhood vs. cumulative), whenever at least 3 relevant effect sizes were available. Childhood lead exposure was positively associated with ADHD diagnosis and symptoms in all analyses except for the prenatal analyses (odds ratios (ORs) ranging from 1.60 to 2.62, correlation coefficients (CCs) ranging from 0.14 to 0.16). Other statistically significant associations were limited to organophosphates (CC = 0.11, 95% confidence interval (CI): 0.03–0.19 for continuous measures of ADHD outcomes overall), polychlorinated biphenyls (CC = 0.08, 95% CI: 0.02–0.14 for continuous measures of inattention as the outcome), and both prenatal and childhood mercury exposure (CC = 0.02, 95% CI: 0.00–0.04 for continuous measures of ADHD outcomes overall for either exposure window). Our findings provide further support for negative impacts of prenatal and/or childhood exposure to certain chemicals and raise the possibility that primary prevention and targeted screening could prevent or mitigate ADHD symptomatology. Furthermore, these findings support the need for regular review of regulations as our scientific understanding of the risks posed by these chemicals evolves. [ABSTRACT FROM AUTHOR]

Although neurobiologic and genetic factors figure prominently in the development of attention deficit/hyperactivity disorder (ADHD), adverse physical health experiences and conditions encountered during childhood may also play a role. Poor health is known to impact the developing brain with potential lifelong implications for behavioral issues. In attempt to better understand the relationship between childhood physical health and the onset and presence of ADHD symptoms, we summarized international peer-reviewed articles documenting relationships between a select group of childhood diseases or health events (e.g., illnesses, injuries, syndromes) and subsequent ADHD outcomes among children ages 0–17 years. Drawing on a larger two-phase systematic review, 57 longitudinal or retrospective observational studies (1978–2021) of childhood allergies, asthma, eczema, head injury, infection, or sleep problems and later ADHD diagnosis or symptomatology were identified and subjected to meta-analysis. Significant associations were documented between childhood head injuries, infections, and sleep problems with both dichotomous and continuous measures of ADHD, and between allergies with dichotomous measures of ADHD. We did not observe significant associations between asthma or eczema with ADHD outcomes. Heterogeneity detected for multiple associations, primarily among continuously measured outcomes, underscores the potential value of future subgroup analyses and individual studies. Collectively, these findings shed light on the importance of physical health in understanding childhood ADHD. Possible etiologic links between physical health factors and ADHD are discussed, as are implications for prevention efforts by providers, systems, and communities. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Poor parental mental health and stress have been associated with children's mental disorders, including attention-deficit/hyperactivity disorder (ADHD), through social, genetic, and neurobiological pathways. To determine the strength of the associations between parental mental health and child ADHD, we conducted a set of meta-analyses to examine the association of parent mental health indicators (e.g., parental depression, antidepressant usage, antisocial personality disorder, and stress and anxiety) with subsequent ADHD outcomes in children. Eligible ADHD outcomes included diagnosis or symptoms. Fifty-eight articles published from 1980 to 2019 were included. We calculated pooled effect sizes, accounting for each study's conditional variance, separately for test statistics based on ADHD as a dichotomous (e.g., diagnosis or clinical cutoffs) or continuous measurement (e.g., symptoms of ADHD subtypes of inattentiveness and hyperactivity/impulsivity). Parental stress and parental depression were significantly associated with increased risk for ADHD overall and both symptoms and diagnosis. Specifically, maternal stress and anxiety, maternal prenatal stress, maternal depression, maternal post-partum depression, and paternal depression were positively associated with ADHD. In addition, parental depression was associated with symptoms of ADHD inattentive and hyperactive/impulsive subtypes. Parental antisocial personality disorder was also positively associated with ADHD overall and specifically ADHD diagnosis. Prenatal antidepressant usage was associated with ADHD when measured dichotomously only. These findings raise the possibility that prevention strategies promoting parental mental health and addressing parental stress could have the potential for positive long-term impacts on child health, well-being, and behavioral outcomes. [ABSTRACT FROM AUTHOR]

Previous studies have shown mixed results on the relationship between prenatal, birth, and postnatal ("pregnancy-related") risk factors and attention-deficit/hyperactivity disorder (ADHD). We conducted meta-analyses to identify potentially modifiable pregnancy-related factors associated with ADHD. A comprehensive search of PubMed, Web of Science, and EMBASE in 2014, followed by an updated search in January 2021, identified 69 articles published in English on pregnancy-related risk factors and ADHD for inclusion. Risk factors were included in the meta-analysis if at least three effect sizes with clear pregnancy-related risk factor exposure were identified. Pooled effect sizes were calculated for ADHD overall, ADHD diagnosis, inattention, and hyperactivity/impulsivity. Odds ratios (OR) were calculated for dichotomous measures and correlation coefficients (CC) for continuous measures. Prenatal factors (pre-pregnancy weight, preeclampsia, pregnancy complications, elevated testosterone exposure), and postnatal factors (Apgar score, neonatal illness, no breastfeeding) were positively associated with ADHD overall; the findings for ADHD diagnosis were similar with the exception that there were too few effect sizes available to examine pre-pregnancy weight and lack of breastfeeding. Prenatal testosterone was significantly associated with inattention and hyperactivity/impulsivity. Effect sizes were generally small (range 1.1–1.6 ORs, -0.16–0.11 CCs). Risk factors occurring at the time of birth (perinatal asphyxia, labor complications, mode of delivery) were not significantly associated with ADHD. A better understanding of factors that are consistently associated with ADHD may inform future prevention strategies. The findings reported here suggest that prenatal and postnatal factors may serve as potential targets for preventing or mitigating the symptoms of ADHD. [ABSTRACT FROM AUTHOR]

Parenting and family environment have significant impact on child development, including development of executive function, attention, and self-regulation, and may affect the risk of developmental disorders including attention-deficit/hyperactivity disorder (ADHD). This paper examines the relationship of parenting and family environment factors with ADHD. A systematic review of the literature was conducted in 2014 and identified 52 longitudinal studies. A follow-up search in 2021 identified 7 additional articles, for a total of 59 studies that examined the association of parenting factors with ADHD outcomes: ADHD overall (diagnosis or symptoms), ADHD diagnosis specifically, or presence of the specific ADHD symptoms of inattention and hyperactivity/impulsivity. For parenting factors that were present in three or more studies, pooled effect sizes were calculated separately for dichotomous or continuous ADHD outcomes, accounting for each study's conditional variance. Factors with sufficient information for analysis were parenting interaction quality (sensitivity/warmth, intrusiveness/reactivity, and negativity/harsh discipline), maltreatment (general maltreatment and physical abuse), parental relationship status (divorce, single parenting), parental incarceration, and child media exposure. All factors showed a significant direct association with ADHD outcomes, except sensitivity/warmth which had an inverse association. Parenting factors predicted diagnosis and overall symptoms as well as inattentive and hyperactive symptoms when measured, but multiple factors showed significant heterogeneity across studies. These findings support the possibility that parenting and family environment influences ADHD symptoms and may affect a child's likelihood of being diagnosed with ADHD. Prevention strategies that support parents, such as decreasing parenting challenges and increasing access to parent training in behavior management, may improve children's long-term developmental health. [ABSTRACT FROM AUTHOR]