Environmental Pollutants and Neurodevelopment: Review of Benefits From Closure of a Coal-Burning Power Plant in Tongliang, China

Brain-derived neurotrophic factor (BDNF): an effect biomarker of neurodevelopment in human biomonitoring programs

The present narrative review summarizes recent findings focusing on the role of brain-derived neurotrophic factor (BDNF) as a biomarker of effect for neurodevelopmental alterations during adolescence, based on health effects of exposure to environmental chemical pollutants. To this end, information was gathered from the PubMed database and the results obtained in the European project Human Biomonitoring for Europe (HBM4EU), in which BDNF was measured at two levels of biological organization: total BDNF protein (serum) and BDNF gene DNA methylation (whole blood) levels. The obtained information is organized as follows. First, human biomonitoring, biomarkers of effect and the current state of the art on neurodevelopmental alterations in the population are presented. Second, BDNF secretion and mechanisms of action are briefly explained. Third, previous studies using BDNF as an effect biomarker were consulted in PubMed database and summarized. Finally, the impact of bisphenol A (BPA), metals, and non-persistent pesticide metabolites on BDNF secretion patterns and its mediation role with behavioral outcomes are addressed and discussed. These findings were obtained from three pilot studies conducted in HBM4EU project. Published findings suggested that exposure to some chemical pollutants such as fine particle matter (PM), PFAS, heavy metals, bisphenols, and non-persistent pesticides may alter circulating BDNF levels in healthy population. Therefore, BDNF could be used as a valuable effect biomarker to investigate developmental neurotoxicity of some chemical pollutants.

On the COP26 and coal's phase-out agenda: Striking a balance among the environmental, economic, and health impacts of coal consumption

Economic and environmental policy actions are often substitutionary in their impacts, as one man's food could be another's poison. One of the critical emphases at the recent Conference of Parties 26 (COP26) is the need for coal to be phased out in the energy consumption basket of nations to achieve environmental sustainability, but this could be at the expense of the positive performance of other socio-economic fundamentals. The best bet could then be to maintain an optimal consumption level to strike a balance. Relying on this, we examine the environmental, economic, and health impacts of coal consumption in the world's highest coal-consuming countries, putting the latter's threshold level into consideration. In summary, we find that there is a trade-off between pushing for a sustainable environment through a reduction in coal consumption and achieving better growth and health status. This implies that phasing out of coal totally will have severe economic and health costs. However, based on our threshold regression model results, it is most reasonable to maintain a lower level of coal use in the overall energy mix of these countries. This will definitely yield a relatively low level of carbon, but will still assure a certain level of economic growth and health performance. As such, reducing the intensity of coal gradually and simultaneously providing a substitute that can also serve economic and health needs are encouraged.

Animal-to-Human Translation Difficulties and Problems With Proposed Coding-in-Noise Deficits in Noise-Induced Synaptopathy and Hidden Hearing Loss

Noise induced synaptopathy (NIS) and hidden hearing loss (NIHHL) have been hot topic in hearing research since a massive synaptic loss was identified in CBA mice after a brief noise exposure that did not cause permanent threshold shift (PTS) in 2009. Based upon the amount of synaptic loss and the bias of it to synapses with a group of auditory nerve fibers (ANFs) with low spontaneous rate (LSR), coding-in-noise deficit (CIND) has been speculated as the major difficult of hearing in subjects with NIS and NIHHL. This speculation is based upon the idea that the coding of sound at high level against background noise relies mainly on the LSR ANFs. However, the translation from animal data to humans for NIS remains to be justified due to the difference in noise exposure between laboratory animals and human subjects in real life, the lack of morphological data and reliable functional methods to quantify or estimate the loss of the afferent synapses by noise. Moreover, there is no clear, robust data revealing the CIND even in animals with the synaptic loss but no PTS. In humans, both positive and negative reports are available. The difficulty in verifying CINDs has led a re-examination of the hypothesis that CIND is the major deficit associated with NIS and NIHHL, and the theoretical basis of this idea on the role of LSR ANFs. This review summarized the current status of research in NIS and NIHHL, with focus on the translational difficulty from animal data to human clinicals, the technical difficulties in quantifying NIS in humans, and the problems with the SR theory on signal coding. Temporal fluctuation profile model was discussed as a potential alternative for signal coding at high sound level against background noise, in association with the mechanisms of efferent control on the cochlea gain.

Maternal, neonatal and socio-economic factors associated with intellectual development among children from a coal mining region in Brazil

Coal is the most aggressive energy sources in the environment. Several adverse outcomes on children's health exposure to coal pollutants have been reported. Pollutants from coal power plants adversely affect the intellectual development and capacity. The present study aimed to evaluate the intellectual development and associated factors among children living a city under the direct influence (DI) and six neighboring municipalities under the indirect influence (II) of coal mining activity in the largest coal reserve of Brazil. A structured questionnaire was completed by the child's guardian, and Raven's Progressive Color Matrices were administered to each child to assess intellectual development. A total of 778 children participated. In general, no significant difference was observed between the two cities. The DI city had better socioeconomic conditions than the II municipalities according to family income (< 0.001). The prevalence of children who were intellectually below average or with intellectual disabilities was 22.9%, and there was no significant difference (p > 0.05) between municipalities. In both unadjusted and adjusted analyses, intellectual development was associated with maternal age, marital situation and maternal education level, birth weight, breast feeding, frequent children's daycare, paternal participation in children's care and child growth. Living in the DI area was not associated with intellectual disability. The results suggest that socioeconomic conditions and maternal and neonatal outcomes are more important than environmental factors for intellectual development of children living in a coal mining area.

Associations between household incense burning and delayed motor development among preterm infants modified by gestational age and maternal educational status

BACKGROUND

Household incense burning is a common ritual behavior in the Asia-Pacific region but has been associated with inferior developmental outcomes in term infants. We aimed to examine these associations among preterm infants.

METHODS

Information from 1190 mother-infant pairs during 6- and 18-month follow-up to the Taiwan Birth Cohort Study was examined for associations between household incense burning exposure and infant neurodevelopmental milestone achievement using multivariable Cox proportional hazard model with propensity score weighting, along with stratified, sensitivity, and decomposition analysis.

RESULTS

Household incense burning exposure was associated with delayed gross motor milestone achievement among all preterm infants according to the Cox model and after propensity score weighting. Meanwhile, associations for delayed development were found in gross motor domain milestones among late preterm infants, while fine motor domain delay was found among other preterm infants. Furthermore, the associations between household incense burning status and gross motor milestone delays were attenuated by the interaction between higher education level and household incense burning exposure status.

CONCLUSIONS

Household incense burning exposure was associated with delays, and the motor domains affected differed according to degree of prematurity. These associations were modified by the attenuation upon higher maternal educational status and exposure status interaction.

[Association of exposure to polycyclic aromatic hydrocarbons during pregnancy with autism spectrum disorder-related behaviors in toddlers: a birth cohort study]

OBJECTIVE

To study the association of exposure to polycyclic aromatic hydrocarbons (PAH) during pregnancy and autism spectrum disorder (ASD)-related behaviors in toddlers.

METHODS

A total of 348 toddlers who had accepted the measurement of PAH-DNA adduct in umbilical cord blood and evaluation of behavior problems at the age of 36 months were enrolled in this birth cohort study. Child Behavior Checklist (CBCL) and Autism Behavior Checklist (ABC) were used to evaluate behavior problems at the age of 36 months. The correlation of the concentration of PAH-DNA adduct in umbilical cord blood with CBCL and ABC scores at the age of 36 months were analyzed.

RESULTS

The detection rate of PAH-DNA adduct in umbilical cord blood was 52.3%, and the median concentration was 0.68 ng/mL. The median total scores of CBCL and ABC scales were 23 and 8 respectively. In children aged 36 months, the concentration of PAH-DNA adduct was positively correlated with the score of social withdrawal in the CBCL scale (r_s=0.205, P<0.05), the total score of the ABC scale (r_s=0.412, P<0.05), and the self-care score of the ABC scale (r_s=0.355, P<0.05). The concentration of PAH-DNA adduct was closely associated with the total score of the ABC scale in children aged 36 months (β=0.122, P<0.05).

CONCLUSIONS

PAH exposure during pregnancy may be a risk factor for ASD-related behaviors in toddlers. Effective reduction of PAH exposure during pregnancy and detection of PAH-DNA adduct in neonatal umbilical cord blood are of vital importance for early prevention, screening and intervention of ASD.

Epigenetic and Neurological Impairments Associated with Early Life Exposure to Persistent Organic Pollutants

The incidence of neurodevelopmental and neurodegenerative diseases worldwide has dramatically increased over the last decades. Although the aetiology remains uncertain, evidence is now growing that exposure to persistent organic pollutants during sensitive neurodevelopmental periods such as early life may be a strong risk factor, predisposing the individual to disease development later in life. Epidemiological studies have associated environmentally persistent organic pollutant exposure to brain disorders including neuropathies, cognitive, motor, and sensory impairments; neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD); and neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS). In many ways, this expands the classical “Developmental Origins of Health and Disease” paradigm to include exposure to pollutants. This model has been refined over the years to give the current “three-hit” model that considers the individual's genetic factors as a first “hit.” It has an immediate interaction with the early-life exposome (including persistent organic pollutants) that can be considered to be a second “hit.” Together, these first two “hits” produce a quiescent or latent phenotype, most probably encoded in the epigenome, which has become susceptible to a third environmental “hit” in later life. It is only after the third “hit” that the increased risk of disease symptoms is crystallised. However, if the individual is exposed to a different environment in later life, they would be expected to remain healthy. In this review, we examine the effect of exposure to persistent organic pollutants and particulate matters in early life and the relationship to subsequent neurodevelopmental and neurodegenerative disorders. The roles of those environmental factors which may affect epigenetic DNA methylation and therefore influence normal neurodevelopment are then evaluated.

Neurodevelopmental Effects of Mercury

The toxicology of mercury (Hg) is of concern since this metal is ubiquitously distributed in the environment, and living organisms are routinely exposed to Hg at low to high levels. The toxic effects of Hg are well studied and it is known that they may differ depending on the Hg chemical species. In this chapter, we emphasize the neurotoxic effects of Hg during brain development. The immature brain is more susceptible to Hg exposure, since all the Hg chemical forms, not only the organic ones, can harm it. The possible consequences of Hg exposure during the early stages of development, the additive effects with other co-occurring neurotoxicants, and the known mechanisms of action and targets will be addressed in this chapter.

Pollution from Fossil-Fuel Combustion is the Leading Environmental Threat to Global Pediatric Health and Equity: Solutions Exist

Fossil-fuel combustion by-products are the world's most significant threat to children's health and future and are major contributors to global inequality and environmental injustice. The emissions include a myriad of toxic air pollutants and carbon dioxide (CO₂), which is the most important human-produced climate-altering greenhouse gas. Synergies between air pollution and climate change can magnify the harm to children. Impacts include impairment of cognitive and behavioral development, respiratory illness, and other chronic diseases-all of which may be "seeded" in utero and affect health and functioning immediately and over the life course. By impairing children's health, ability to learn, and potential to contribute to society, pollution and climate change cause children to become less resilient and the communities they live in to become less equitable. The developing fetus and young child are disproportionately affected by these exposures because of their immature defense mechanisms and rapid development, especially those in low- and middle-income countries where poverty and lack of resources compound the effects. No country is spared, however: even high-income countries, especially low-income communities and communities of color within them, are experiencing impacts of fossil fuel-related pollution, climate change and resultant widening inequality and environmental injustice. Global pediatric health is at a tipping point, with catastrophic consequences in the absence of bold action. Fortunately, technologies and interventions are at hand to reduce and prevent pollution and climate change, with large economic benefits documented or predicted. All cultures and communities share a concern for the health and well-being of present and future children: this shared value provides a politically powerful lever for action. The purpose of this commentary is to briefly review the data on the health impacts of fossil-fuel pollution, highlighting the neurodevelopmental impacts, and to briefly describe available means to achieve a low-carbon economy, and some examples of interventions that have benefited health and the economy.