Effects of prenatal exposure to particulate matter air pollution on corpus callosum and behavioral problems in children.

OBJECTIVE: Air pollution (AP) may affect neurodevelopment, but studies about the effects of AP on the growing human brain are still scarce. We aimed to investigate the effects of prenatal exposure to AP on lateral ventricles (LV) and corpus callosum (CC) volumes in children and to determine whether the induced brain changes are associated with behavioral problems. METHODS: Among the children recruited through a set of representative schools of the city of Barcelona, (Spain) in the Brain Development and Air Pollution Ultrafine Particles in School Children (BREATHE) study, 186 typically developing participants aged 8-12 years underwent brain MRI on the same 1.5 T MR unit over a 1.5-year period (October 2012-April 2014). Brain volumes were derived from structural MRI scans using automated tissue segmentation. Behavioral problems were assessed using the Strengths and Difficulties Questionnaire (SDQ) and the criteria of the Attention Deficit Hyperactivity Disorder DSM-IV list. Prenatal fine particle (PM2.5) levels were retrospectively estimated at the mothers' residential addresses during pregnancy with land use regression (LUR) models. To determine whether brain structures might be affected by prenatal PM2.5 exposure, linear regression models were run and adjusted for age, sex, intracranial volume (ICV), maternal education, home socioeconomic vulnerability index, birthweight and mothers' smoking status during pregnancy. To test for associations between brain changes and behavioral outcomes, negative binomial regressions were performed and adjusted for age, sex, ICV. RESULTS: Prenatal PM2.5 levels ranged from 11.8 to 39.5 µg/m3 during the third trimester of pregnancy. An interquartile range increase in PM2.5 level (7 µg/m3) was significantly linked to a decrease in the body CC volume (mm3) (ß = -53.7, 95%CI [-92.0, -15.5] corresponding to a 5% decrease of the mean body CC volume) independently of ICV, age, sex, maternal education, socioeconomic vulnerability index at home, birthweight and mothers' smoking status during the third trimester of pregnancy. A 50 mm3 decrease in the body CC was associated with a significant higher hyperactivity subscore (Rate Ratio (RR) = 1.09, 95%CI [1.01, 1.17) independently of age, sex and ICV. The statistical significance of these results did not survive to False Discovery Rate correction for multiple comparisons. CONCLUSIONS: Prenatal exposure to PM2.5 may be associated with CC volume decrease in children. The consequences might be an increase in behavioral problems.

Video gaming in school children: How much is enough?

OBJECTIVE: Despite extensive debate, the proposed benefits and risks of video gaming in young people remain to be empirically clarified, particularly as regards an optimal level of use. METHODS: In 2,442 children aged 7 to 11 years, we investigated relationships between weekly video game use, selected cognitive abilities, and conduct-related problems. A large subgroup of these children (n = 260) was further examined with magnetic resonance imaging approximately 1 year later to assess the impact of video gaming on brain structure and function. RESULTS: Playing video games for 1 hour per week was associated with faster and more consistent psychomotor responses to visual stimulation. Remarkably, no further change in motor speed was identified in children playing >2 hours per week. By comparison, the weekly time spent gaming was steadily associated with conduct problems, peer conflicts, and reduced prosocial abilities. These negative implications were clearly visible only in children at the extreme of our game-playing distribution, with 9 hours or more of video gaming per week. At a neural level, changes associated with gaming were most evident in basal ganglia white matter and functional connectivity. INTERPRETATION: Significantly better visuomotor skills can be seen in school children playing video games, even with relatively small amounts of use. Frequent weekly use, by contrast, was associated with conduct problems. Further studies are needed to determine whether moderate video gaming causes improved visuomotor skills and whether excessive video gaming causes conduct problems, or whether children who already have these characteristics simply play more video games. Ann Neurol 2016;80:424-433.

Traffic pollution exposure is associated with altered brain connectivity in school children.

Children are more vulnerable to the effects of environmental elements due to their active developmental processes. Exposure to urban air pollution has been associated with poorer cognitive performance, which is thought to be a result of direct interference with brain maturation. We aimed to assess the extent of such potential effects of urban pollution on child brain maturation using general indicators of vehicle exhaust measured in the school environment and a comprehensive imaging evaluation. A group of 263 children, aged 8 to 12 years, underwent MRI to quantify regional brain volumes, tissue composition, myelination, cortical thickness, neural tract architecture, membrane metabolites, functional connectivity in major neural networks and activation/deactivation dynamics during a sensory task. A combined measurement of elemental carbon and NO2 was used as a putative marker of vehicle exhaust. Air pollution exposure was associated with brain changes of a functional nature, with no evident effect on brain anatomy, structure or membrane metabolites. Specifically, a higher content of pollutants was associated with lower functional integration and segregation in key brain networks relevant to both inner mental processes (the default mode network) and stimulus-driven mental operations. Age and performance (motor response speed) both showed the opposite effect to that of pollution, thus indicating that higher exposure is associated with slower brain maturation. In conclusion, urban air pollution appears to adversely affect brain maturation in a critical age with changes specifically concerning the functional domain.

The BROADEN study: The design of an observational study to assess the absolute burden of HPV-related head and neck cancers.

BACKGROUND: Persistent human papillomavirus (HPV) infection is an important risk factor for a subset of head and neck cancers (HNCs). However, estimates of the HPV-attributable fraction of oropharyngeal cancers vary greatly, and the proportion is increasing. Growing evidence indicates smaller proportions of oral cavity and laryngeal cancers are also HPV-attributable, but this requires further investigation. The primary objective of the BROADEN study is to estimate the fraction of HNCs attributable to HPV in selected European and Asian countries by anatomic site. Secondary objectives are to determine HPV genotypes involved and to describe primary tumor and patient characteristics by HPV status. METHODS: BROADEN is a non-interventional, cross-sectional study of patients with HNC in China, France, Germany, Italy, Japan, Portugal, and Spain. The HPV-attributable HNC fraction will be determined within pre-defined time-periods (2008-2009, 2013-2014 [China only], 2018-2019). Approximately 9000 patients from an estimated 90 hospitals with reference HNC diagnostic units and local reference pathology laboratories will participate. Sample size estimates were generated by grouped anatomic site (oropharynx, oral cavity, nasopharynx, hypopharynx, and larynx) and country. HPV testing (HPV-DNA and p16 immunohistochemistry [IHC]) will be performed at a central laboratory on formalin-fixed paraffin-embedded tissue samples. All HPV-DNA-positive samples and HPV-DNA-negative/p16 IHC-positive samples, plus 10% of remaining HPV DNA-negative (control) samples will be tested for HPV mRNA. DISCUSSION: BROADEN is a large global epidemiologic study to estimate current and recent past HPV burden in oropharyngeal and non-oropharyngeal HNCs. BROADEN is expected to provide robust estimates of HPV attributability by anatomic site in participating countries.

A longitudinal study of brain anatomy changes preceding dementia in Down syndrome.

Background: We longitudinally assessed Down syndrome individuals at the age of risk of developing dementia to measure changes in brain anatomy and their relationship to cognitive impairment progression. Methods: Forty-two Down syndrome individuals were initially included, of whom 27 (mean age 46.8 years) were evaluable on the basis of completing the 2-year follow-up and success in obtaining good quality MRI exams. Voxel-based morphometry was used to estimate regional brain volumes at baseline and follow-up on 3D anatomical images. Longitudinal volume changes for the group and their relationship with change in general cognitive status and specific cognitive domains were mapped. Results: As a group, significant volume reduction was identified in the substantia innominata region of the basal forebrain, hippocampus, lateral temporal cortex and left arcuate fasciculus. Volume reduction in the substantia innominata and hippocampus was more prominent in individuals whose clinical status changed from cognitively stable to mild cognitive impairment or dementia during the follow-up. Relevantly, longitudinal memory score change was specifically associated with volume change in the hippocampus, prospective memory with prefrontal lobe and verbal comprehension with language-related brain areas. Conclusions: Results are notably concordant with the well-established anatomical changes signaling the progression to dementia in Alzheimer's disease, despite the dense baseline pathology that developmentally accumulates in Down syndrome. This commonality supports the potential value of Down syndrome as a genetic model of Alzheimer's neurodegeneration and may serve to further support the view that Down syndrome patients are best candidates to benefit from treatment research in Alzheimer's disease.

•Longitudinal changes in brain anatomy were identified in Down syndrome individuals.•Basal forebrain and hippocampal volume reductions paralleled clinical progression.•The overall anatomical pattern identified resembled Alzheimer's neurodegeneration.

The Association between Lifelong Greenspace Exposure and 3-Dimensional Brain Magnetic Resonance Imaging in Barcelona Schoolchildren.

BACKGROUND: Proponents of the biophilia hypothesis believe that contact with nature, including green spaces, has a crucial role in brain development in children. Currently, however, we are not aware of evidence linking such exposure with potential effects on brain structure. OBJECTIVE: We determined whether lifelong exposure to residential surrounding greenness is associated with regional differences in brain volume based on 3-dimensional magnetic resonance imaging (3D MRI) among children attending primary school. METHODS: We performed a series of analyses using data from a subcohort of 253 Barcelona schoolchildren from the Brain Development and Air Pollution Ultrafine Particles in School Children (BREATHE) project. We averaged satellite-based normalized difference vegetation index (NDVI) across 100-m buffers around all residential addresses since birth to estimate each participant's lifelong exposure to residential surrounding greenness, and we used high-resolution 3D MRIs of brain anatomy to identify regional differences in voxel-wise brain volume associated with greenness exposure. In addition, we performed a supporting substudy to identify regional differences in brain volume associated with measures of working memory (d' from computerized n-back tests) and inattentiveness (hit reaction time standard error from the Attentional Network Task instrument) that were repeated four times over one year. We also performed a second supporting substudy to determine whether peak voxel tissue volumes in brain regions associated with residential greenness predicted cognitive function test scores. RESULTS: Lifelong exposure to greenness was positively associated with gray matter volume in the left and right prefrontal cortex and in the left premotor cortex and with white matter volume in the right prefrontal region, in the left premotor region, and in both cerebellar hemispheres. Some of these regions partly overlapped with regions associated with cognitive test scores (prefrontal cortex and cerebellar and premotor white matter), and peak volumes in these regions predicted better working memory and reduced inattentiveness. CONCLUSION: Our findings from a study population of urban schoolchildren in Barcelona require confirmation, but they suggest that being raised in greener neighborhoods may have beneficial effects on brain development and cognitive function. https://doi.org/10.1289/EHP1876.

Anomalous White Matter Structure and the Effect of Age in Down Syndrome Patients.

BACKGROUND: Neural tissue alterations in Down syndrome are fully expressed at relatively late developmental stages. In addition, there is an early presence of neurodegenerative changes in the late life stages. OBJECTIVE: The aims of this study were both to characterize white matter abnormalities in the brain of adult Down syndrome patients using diffusion tensor imaging (DTI) and to investigate whether degenerative alterations in white matter structure are detectable before dementia is clinically evident. METHODS: Forty-five adult non-demented Down syndrome patients showing a wide age range (18-52 years) and a matched 45-subject control group were assessed. DTI fractional anisotropy (FA) brain maps were generated and selected cognitive tests were administered. RESULTS: Compared with healthy controls, non-demented Down syndrome patients showed lower DTI FA in white matter involving the major pathways, but with more severe alterations in the frontal-subcortical circuits. White matter FA decreased with age at a similar rate in both DS and control groups. CONCLUSIONS: Our results contribute to characterizing the expression of white matter structural alterations in adult Down syndrome. However, an accelerated aging effect was not demonstrated, which may suggest that the FA measurements used are not sufficiently sensitive or, alternatively, age-related white matter neurodegeneration is not obvious prior to overt clinical dementia.

Airborne copper exposure in school environments associated with poorer motor performance and altered basal ganglia.

INTRODUCTION: Children are more vulnerable to the effects of environmental elements. A variety of air pollutants are among the identified factors causing neural damage at toxic concentrations. It is not obvious, however, to what extent the tolerated high levels of air pollutants are able to alter brain development. We have specifically investigated the neurotoxic effects of airborne copper exposure in school environments. METHODS: Speed and consistency of motor response were assessed in 2836 children aged from 8 to 12 years. Anatomical MRI, diffusion tensor imaging, and functional MRI were used to directly test the brain repercussions in a subgroup of 263 children. RESULTS: Higher copper exposure was associated with poorer motor performance and altered structure of the basal ganglia. Specifically, the architecture of the caudate nucleus region was less complete in terms of both tissue composition and neural track water diffusion. Functional MRI consistently showed a reciprocal connectivity reduction between the caudate nucleus and the frontal cortex. CONCLUSIONS: The results establish an association between environmental copper exposure in children and alterations of basal ganglia structure and function.

A Genome-Wide Association Study of Attention Function in a Population-Based Sample of Children.

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.