Effects of prenatal exposure to NO2 on children’s neurodevelopment: a systematic review and meta-analysis

Abstract

The neurotoxicity of NO 2 exposure is well-known and potentially causes impaired of neural functions. This review aimed to estimate associations between prenatal NO 2 exposure and neurodevelopment for children. Articles published until May 2019 reported prenatal NO 2 exposure and children's cognition, psychomotor, language, attention, IQ, and behavior function were searched according to all related terms. The main databases we retrieved included PubMed, Web of Science, Embase, and Cochrane Library. Coefficient was extracted, conversed, and synthesized by random effects meta-analysis. Meanwhile, qualitatively describe would be used for some studies which cannot be synthesized quantitatively for lack of quantity or methods inconsistency. Finally, a total of 3848 citations were searched, and only 10 studies were included. We estimated that per 10 μg/m 3 increase of NO 2 during pregnancy was associated with a − 0.76 point decrease in global psychomotor (95% CI, − 1.34, − 0.18) and a − 0.62 point decrease in fine psychomotor for children (95% CI, − 1.09, − 0.16). But no significant association found in general cognitive and language. In addition, through the literature review, it seemed that prenatal exposure to NO 2 might cause adverse impacts on children's attention, IQ, and different behaviors, but this requires confirmation from further researches. Our study indicated that prenatal exposure to NO 2 seems to be associated with impaired neural development for children, especially for fine psychomotor. However, further studies are needed for determining the effects of prenatal air pollution exposure on attention, IQ, and behavior.

Air pollution and neurological development in children

“…29,30 In addition, exposure to NO 2 is associated with impaired psychomotor development after birth. 31 Pregnant females who lived closer to major roadways and are exposed to higher traffic-related pollutants have a higher risk of having a child with autism, decreased cognitive functions, and deficits in communication, memory, and attention functions. 8,22,32 A new cohort study also suggests pre-and postnatal exposures to pollution are associated with white matter microstructural changes (lower fractional anisotropy and higher mean diffusivity) in pre-adolescent years.…”

“…59 Despite the mounting evidence suggesting that air pollution has deleterious effects on neurological development, it is important also to acknowledge that not all studies confirmed this association. 26,31,50,60 For example, in a recent systematic review/meta-analysis that examined the effects of fine particulate exposures on ADHD, three of the 12 studies that met inclusion criteria did not find any association. 60 The discrepancies in findings across some studies are probably a result of heterogeneity in various aspects of study design.…”

“…Higher PM 2.5 is also correlated with reduced cortical thickness, thinner gray matter, reduction in the volume of the corpus callosum, and smaller cerebral cortex, all of which have major implications for information processing, learning, memory, and impulse control 29,30 . In addition, exposure to NO 2 is associated with impaired psychomotor development after birth 31 . Pregnant females who lived closer to major roadways and are exposed to higher traffic‐related pollutants have a higher risk of having a child with autism, decreased cognitive functions, and deficits in communication, memory, and attention functions 8,22,32 .…”

Anesthetic Exposure During Childhood and Neurodevelopmental Outcomes

“…Diffuse distributions of deficits, such as those we observed in this study, have been reported in studies of other neurotoxic exposures, with the possibility of some clustering around certain domains. 133 , 134 In particular, in this study, the outcome with the largest SMD was the subdomain of externalizing behavioral problems, which are commonly found in children with ADHD. 135 The increased rates of neurodevelopmental disorder and ADHD diagnoses is also consistent with studies of other neurotoxic exposures, specifically, children exposed to pesticides have reported behavioral problems, with 50% to 142% increased risks of ADHD and symptoms of hyperactivity.…”

Neurobehavioural and cognitive effects of prenatal exposure to organochlorine compounds in three year old children

“…In this older cohort (2002)(2003)(2004), representative for the Dutch speaking Flemish population, attention was paid to controlling for confounding factors, although not all confounding factors could be taken into consideration (e.g. the possible influence of air pollution on brain function) [29]. Analyses did not indicate bias by co-exposure of Pb and Cd, which were measured as ubiquitous neurotoxic environmental polluting metals in cord blood .…”