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Introduction: This study aimed to estimate risks of cardiovascular and cerebrovascular events in patients treated with lisdexamfetamine dimesylate (LDX) compared with patients previously treated with other attention-deficit/hyperactivity disorder (ADHD) medications (amphetamine, dexamphetamine, methylphenidate or atomoxetine). Methods: This population-based cohort study used data from Danish and Swedish medical and administrative national registers. The LDX cohort included adult patients initiating LDX with at least 12 months' data preceding first LDX dispensing (index date). A random sample of patients treated with at least one non-LDX ADHD medication in the 6–24 months (but not less than 6 months) before index date (previous-users cohort) were matched to LDX users on age, sex, region and calendar year. The primary outcome, a composite of major adverse cardiovascular and cerebrovascular events (MACE), included first hospitalisation for acute myocardial infarction or stroke and out-of-hospital coronary heart disease or cerebrovascular disease death. Incidence rates (IRs) and IR ratios (IRRs) with 95% confidence intervals (CIs) of MACE were estimated using Poisson regression. Results: From Denmark/Sweden, 5516/40,163 LDX users and 27,494/200,389 previous users were included. In Denmark, IRs of MACE/1000 person-years (95% CI) were similar for LDX (1.63 [0.85–3.14]) and previous users (1.61 [1.28–2.01]). In Sweden, IRs (95% CI) were 1.40 (1.09–1.79) in LDX users and 1.17 (1.00–1.38) in previous users. Adjusted MACE IRRs (95% CI) for LDX versus previous use were 1.01 (0.48–2.13) in Denmark, 1.13 (0.75–1.71) in Sweden, and 1.10 (0.77–1.58) in the pooled analysis. Conclusion: Our findings suggest little to no increased risk of cardiovascular and cerebrovascular events in patients treated with LDX compared with patients previously treated with other ADHD medications. [ABSTRACT FROM AUTHOR]

INTRODUCTION: To date, the evidence for an association between perfluoroalkyl substances (PFAS) exposure and attention deficit and hyperactivity disorder (ADHD) is inconclusive. OBJECTIVE: We investigated the association between early life exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), and ADHD in a collaborative study including nine European population-based studies, encompassing 4,826 mother–child pairs. METHODS: Concentrations of PFOS and PFOA were measured in maternal serum/plasma during pregnancy, or in breast milk, with different timing of sample collection in each cohort. We used a validated pharmacokinetic model of pregnancy and lactation to estimate concentrations of PFOS and PFOA in children at birth and at 3, 6, 12, and 24 months of age. We classified ADHD using recommended cutoff points for each instrument used to derive symptoms scores. We used multiple imputation for missing covariates, logistic regression to model the association between PFAS exposure and ADHD in each study, and combined all adjusted study-specific effect estimates using random-effects meta-analysis. RESULTS: A total of 399 children were classified as having ADHD, with a prevalence ranging from 2.3% to 7.3% in the studies. Early life exposure to PFOS or PFOA was not associated with ADHD during childhood [odds ratios (ORs) ranging from 0.96 (95% CI: 0.87, 1.06) to 1.02 (95% CI: 0.93, 1.11)]. Results from stratified models suggest potential differential effects of PFAS related to child sex and maternal education. CONCLUSION: We did not identify an increased prevalence of ADHD in association with early life exposure to PFOS and PFOA. However, stratified analyses suggest that there may be an increased prevalence of ADHD in association with PFAS exposure in girls, in children from nulliparous women, and in children from low-educated mothers, all of which warrant further exploration. [ABSTRACT FROM AUTHOR]

Background: Attention-deficit/hyperactivity disorder (ADHD) is increasing worldwide for reasons largely unknown and environmental chemicals with neurotoxic properties, such as persistent organic pollutants (POPs), have been proposed to play a role. We investigated the association between prenatal and postnatal exposure to polychlorinated biphenyl-153 (PCB-153), p-p´-dichlorodiphenyldichloroethylene (p-p'-DDE) and hexachlorobenzene (HCB) and ADHD in childhood.Methods: We pooled seven European birth cohort studies encompassing 4437 mother-child pairs from the general population with concentrations of PCB-153, p-p´-DDE and HCB measured in cord blood, maternal blood or milk. We then calculated prenatal (birth) and postnatal (3, 6, 12 and 24 months) POP concentrations using a pharmacokinetic model. The operational definition of ADHD varied across cohorts and ranged from doctor diagnosis obtained from patient registries to maternal or teachers reports. We used multilevel (mixed) logistic regression models to estimate the associations between exposure to POPs at birth, 3, 6, 12 and 24 months and ADHD.Results: The global prevalence of ADHD in our study was 6%. The mean age at assessment of ADHD was 5.8 years (range: 3.8-9.5 years). We found no association between exposure to PCB-153, p-p´-DDE and HCB at any age point between birth and 24 months and ADHD, in the pooled analyses (pooled odds ratios ranging from 1.00 to 1.01). A number of sensitivity analyses gave basically the same results.Conclusions: In the largest study to date of 4437 children in seven European birth cohorts, we did not observe any association between either pre- or postnatal exposure (up to 24 months) to PCB-153, p-p´-DDE and HCB and the risk of ADHD before the age of 10 years. [ABSTRACT FROM AUTHOR]

BACKGROUND: Traffic-related air pollution is emerging as a risk factor for Alzheimer's disease (AD) and impaired brain development. Individual differences in vulnerability to air pollution may involve the ∊4 allele of Apolipoprotein E (APOE) gene, the primary genetic risk factor for AD. OBJECTIVE: We analyzed whether the association between traffic air pollution and neurodevelopmental outcomes is modified by APOE ∊4 status in children. METHODS: Data on parent-reported behavior problems (total difficulties scores, Strengths and Difficulties Questionnaire), teacher-reported attentiondeficit hyperactivity disorder (ADHD) symptom scores, cognitive performance trajectories (computerized tests of inattentiveness and working memory repeated 2-4 times during January 2012-March 2013), and APOE genotypes were obtained for 1,667 children age 7-11 y attending 39 schools in or near Barcelona. Basal ganglia volume (putamen, caudate, and globus pallidum) was measured in 163 of the children by MRI (October 2012-April 2014.) Average annual outdoor polycyclic aromatic hydrocarbons (PAHs), elemental carbon (EC), and nitrogen dioxide (NO2 concentrations were estimated based on measurements at each school (two 1-wk campaigns conducted 6 months apart in 2012). RESULTS: APOE ∊4 allele carriers had significantly higher behavior problem scores than noncarriers, and adverse associations with PAHs and NO2 were stronger or limited to ∊4 carriers for behavior problem scores (P-interaction 0.03 and 0.04), caudate volume (P-interaction 0.04 and 0.03), and inattentiveness trajectories (P-interaction 0.15 and 0.08, respectively). Patterns of associations with the same outcomes were similar for EC. CONCLUSION: PAHs, EC, and NO2 were associated with higher behavior problem scores, smaller reductions in inattentiveness over time, and smaller caudate volume in APOE ∊4 allele carriers in our study population, and corresponding associations were weak or absent among ∊4 noncarriers. These findings support a potential role of APOE in biological mechanisms that may contribute to associations between air pollution and neurobehavioral outcomes in children. [ABSTRACT FROM AUTHOR]

Background: Attention function filters and selects behaviorally relevant information. This capacity is impaired in some psychiatric disorders and has been proposed as an endophenotype for Attention-Deficit/Hyperactivity Disorder; however, its genetic basis remains largely unknown. This study aimed to identify single nucleotide polymorphism (SNPs) associated with attention function. Materials and Methods: The discovery sample included 1655 children (7–12 years) and the replication sample included 546 children (5–8 years). Five attention outcomes were assessed using the computerized Attentional Network Test (ANT): alerting, orienting, executive attention, Hit Reaction time (HRT) and the standard error of HRT (HRTSE). A Genome-wide Association Study was conducted for each outcome. Gene set enrichment analyses were performed to detect biological pathways associated with attention outcomes. Additional neuroimaging analyses were conducted to test neural effects of detected SNPs of interest. Results: Thirteen loci showed suggestive evidence of association with attention function (P<10−5) in the discovery sample. One of them, the rs4321351 located in the PID1 gene, was nominally significant in the replication sample although it did not survive multiple testing correction. Neuroimaging analysis revealed a significant association between this SNP and brain structure and function involving the frontal-basal ganglia circuits. The mTOR signaling and Alzheimer disease-amyloid secretase pathways were significantly enriched for alerting, orienting and HRT respectively (FDR<5%). Conclusion: These results suggest for the first time the involvement of the PID1 gene, mTOR signaling and Alzheimer disease-amyloid secretase pathways, in attention function during childhood. These genes and pathways have been proposed to play a role in neuronal plasticity, memory and neurodegenerative disease. [ABSTRACT FROM AUTHOR]

BACKGROUND: The available evidence of the effects of air pollution and noise on behavioral development is limited, and it overlooks exposure at schools, where children spend a considerable amount of time. OBJECTIVE: We aimed to investigate the associations of exposure to traffic-related air pollutants (TRAPs) and noise at school on behavioral development of schoolchildren. METHODS: We evaluated children 7-11 years of age in Barcelona (Catalonia, Spain) during 2012-2013 within the BREATHE project. Indoor and outdoor concentrations of elemental carbon (EC), black carbon (BC), and nitrogen dioxide (NO[sub 2]) were measured at schools in two separate 1-week campaigns. In one campaign we also measured noise levels inside classrooms. Parents filled out the strengths and difficulties questionnaire (SDQ) to assess child behavioral development, while teachers completed the attention deficit/hyperactivity disorder criteria of the DSM-IV (ADHD-DSM-IV) list to assess specific ADHD symptomatology. Negative binomial mixed-effects models were used to estimate associations between the exposures and behavioral development scores. RESULTS: Interquartile range (IQR) increases in indoor and outdoor EC, BC, and NO2 concentrations were positively associated with SDQ total difficulties scores (suggesting more frequent behavioral problems) in adjusted multivariate models, whereas noise was significantly associated with ADHD-DSM-IV scores. CONCLUSION: In our study population of 7- to 11-year-old children residing in Barcelona, exposure to TRAPs at school was associated with increased behavioral problems in schoolchildren. Noise exposure at school was associated with more ADHD symptoms. [ABSTRACT FROM AUTHOR]

Background Bisphenol A (BPA) may be a neurodevelopmental toxicant, but evidence is not consistent in terms of the sex-specific patterns of the associations and the specific behavioral or cognitive domains most affected. Objective To examine the effects of prenatal BPA exposure on cognitive, psychomotor, and behavioral development in 438 children at 1, 4 and 7 years of age. Methods BPA was measured in spot urine samples collected in trimester 1 and 3 of pregnancy from women participating in the INMA-Sabadell birth cohort study. Cognitive and psychomotor development was assessed at 1 and 4 years using psychologist-based scales. Attention deficit hyperactivity disorder (ADHD) symptoms and other behavioral problems were assessed at 4 years by teachers and at 7 years by parents using questionnaire-based rating scales. Results Geometric mean creatinine-adjusted BPA concentration of the averaged samples was 2.6 μg/g creatinine. BPA exposure was not associated with the cognitive scores or their subscales at 1 and 4 years of age. At 1 year of age, exposure in the highest tertile of BPA concentrations was associated with a reduction of psychomotor scores (T3 vs T1 β =−4.28 points, 95% CI: −8.15, −0.41), but there was no association with psychomotor outcomes at 4 years. At 4 years, BPA exposure was associated with an increased risk of ADHD-hyperactivity symptoms (Incidence Rate Ratio (IRR) per log 10 μg BPA/g creatinine increase=1.72; 1.08, 2.73) and this association was stronger in boys than in girls. Further, boys had an increased risk of ADHD-inattention symptoms whereas girls showed a reduced risk ( p for interaction <0.1). At 7 years, these associations were not statistically significant nor were any other behavioral problems. Conclusions These results suggest that prenatal BPA exposure does not affect cognitive development up to age 4 years. Associations are observed with psychomotor development and ADHD-related symptoms at early ages, but these do not appear to persist until later ages. [ABSTRACT FROM AUTHOR]

Background: Green spaces have been associated with improved mental health in children; however, available epidemiological evidence on their impact on child behavioral development is scarce. Objectives: We investigated the impact of contact with green spaces and blue spaces (beaches) on indicators of behavioral development and symptoms of attention deficit/hyperactivity disorder (ADHD) in schoolchildren. Methods: This study was based on a sample of 2,111 schoolchildren (7–10 years of age) from 36 schools in Barcelona in 2012. We obtained data on time spent in green spaces and beaches and Strengths and Difficulties Questionnaires (SDQ) from parents, and ADHD/DSM-IV questionnaires from teachers. Surrounding greenness was abstracted as the average Normalized Difference Vegetation Index (NDVI) in buffers of 100 m, 250 m, and 500 m around each home address. Proximity to green spaces was defined as living within 300 m of a major green space (≥ 0.05 km2). We applied quasi-Poisson mixed-effects models (with school random effect) to separately estimate associations between indicators of contact with green spaces and SDQ and ADHD total and subscale scores. Results: We generally estimated beneficial associations between behavioral indicators and longer time spent in green spaces and beaches, and with residential surrounding greenness. Specifically, we found statistically significant inverse associations between green space playing time and SDQ total difficulties, emotional symptoms, and peer relationship problems; between residential surrounding greenness and SDQ total difficulties and hyperactivity/inattention and ADHD/DSM-IV total and inattention scores; and between annual beach attendance and SDQ total difficulties, peer relationship problems, and prosocial behavior. For proximity to major green spaces, the results were not conclusive. Conclusion: Our findings support beneficial impacts of contact with green and blue spaces on behavioral development in schoolchildren. [ABSTRACT FROM AUTHOR]

Highlights: [•] Concentrations of seven metals (cobalt, copper, arsenic, cadmium, antimony, thallium and lead) were measured at 1st and 3rd trimester of pregnancy. [•] No statistically significant associations were found between metals and general cognitive scale or executive function of the MSCA. [•] Prenatal exposure to metals was not associated to ADHD symptomatology at the age of 4 years. [Copyright &y& Elsevier]

Background Polycyclic aromatic hydrocarbons (PAHs) have been proposed as environmental risk factors for attention deficit hyperactivity disorder (ADHD). The effects of these pollutants on brain structures potentially involved in the pathophysiology of ADHD are unknown. Objective The aim of this study was to investigate the effects of PAHs on basal ganglia volumes and ADHD symptoms in school children. Methods We conducted an imaging study in 242 children aged 8–12 years, recruited through a set of representative schools of the city of Barcelona, Spain. Indoor and outdoor PAHs and benzo[ a ]pyrene (BPA) levels were assessed in the school environment, one year before the MRI assessment. Whole-brain volumes and basal ganglia volumes (caudate nucleus, globus pallidus, putamen) were derived from structural MRI scans using automated tissue segmentation. ADHD symptoms (ADHD/DSM-IV Scales, American Psychiatric Association 2002) were reported by teachers, and inattentiveness was evaluated with standard error of hit reaction time in the attention network computer-based test. Results Total PAHs and BPA were associated with caudate nucleus volume (CNV) (i.e., an interquartile range increase in BPA outdoor level (67 pg/m 3 ) and indoor level (76 pg/m 3 ) was significantly linked to a decrease in CNV (mm 3 ) (β = − 150.6, 95% CI [− 259.1, − 42.1], p = 0.007, and β = − 122.4, 95% CI [− 232.9, − 11.8], p = 0.030 respectively) independently of intracranial volume, age, sex, maternal education and socioeconomic vulnerability index at home). ADHD symptoms and inattentiveness increased in children with higher exposure to BPA, but these associations were not statistically significant. Conclusions Exposure to PAHs, and in particular to BPA, is associated with subclinical changes on the caudate nucleus, even below the legislated annual target levels established in the European Union. The behavioral consequences of this induced brain change were not identified in this study, but given the caudate nucleus involvement in many crucial cognitive and behavior processes, this volume reduction is concerning for the children's neurodevelopment. [ABSTRACT FROM AUTHOR]

Abstract: There are at present very few studies of the effects of polybromodiphenyl ethers (PBDEs), used as flame retardants in consumer products, on neurodevelopment or thyroid hormone levels in humans. The present study aims to examine the association between pre and postnatal PBDE concentrations and neurodevelopment and thyroid hormone levels in children at age 4years and isolate the effects of PBDEs from those of PCBs, DDT, DDE and HCB. A prospective birth cohort in Menorca (Spain) enrolled 482 pregnant mothers between 1997 and 1998. At 4years, children were assessed for motor and cognitive function (McCarthy Scales of Children''s Abilities), attention-deficit, hyperactivity and impulsivity (ADHD-DSM-IV) and social competence (California Preschool Social Competence Scale). PBDE concentrations were measured in cord blood (N=88) and in serum of 4years olds (N=244). Among all congeners analyzed only PBDE 47 was quantified in a reasonable number of samples (LOQ=0.002ng/ml). Exposure to PBDE 47 was analyzed as a dichotomous variable: concentrations above the LOQ (exposed) and concentrations below (referents). Scores for cognitive and motor functions were always lower in children pre and postnatally exposed to PBDE47 than in referents, but none of these associations was statistically significant (β coefficient (95%CI) of the total cognition score: −2.7 (−7.0, 1.6) for postnatal exposure, and −1.4 (−9.2, 6.5) for prenatal exposure). Postnatal exposure to PBDE 47 was statistically significantly related to an increased risk of symptoms on the attention deficit subscale of ADHD symptoms (RR (95%CI)=1.8 (1.0, 3.2)) but not to hyperactivity symptoms. A statistically significant higher risk of poor social competence symptoms was observed as a consequence of postnatal PBDE 47 exposure (RR (95%CI)=2.6 (1.2, 5.9)). Adjustment for other organochlorine compounds did not influence the results. Levels of thyroid hormones were not associated to PBDE exposure. This study highlights the importance of assessing the effects of PBDE exposure not just prenatally but also during the early years of life. In the light of current evidence a precautionary approach towards PBDE exposure of both mothers and children seems warranted. [Copyright &y& Elsevier]