Air quality impacts early brain development
Study explores how living close to roadways may impact the brain
June 17, 2020
Science Daily/University of California - Davis
Researchers at the University of California, Davis, have found a link between traffic-related air pollution and an increased risk for changes in brain development relevant to neurodevelopmental disorders. Their study, based on rodent models, corroborates previous epidemiological evidence showing this association.
While air pollution has long been a concern for pulmonary and cardiovascular health, it has only been within the past decade that scientists have turned their attention to its effects on the brain, said UC Davis toxicologist Pamela Lein, senior author of the study, recently published in Translational Psychiatry.
Researchers had previously documented links between proximity to busy roadways and neurodevelopmental disorders such as autism, but preclinical data based on real-time exposures to traffic-related air pollution was scarce to nonexistent.
Lein worked with UC Davis atmospheric scientist Anthony Wexler and first author Kelley Patten, a doctoral student in the UC Davis graduate group for pharmacology and toxicology, to develop a novel approach to study the impacts of traffic-related air pollution in real time. They set up a vivarium near a traffic tunnel in Northern California so they could mimic, as closely as possible, the experience of humans in a rodent model.
"This approach was a creative way to get at the question of what impacts air pollution has on the brain in the absence of confounding factors such as socioeconomic influences, diet, etc.," Lein said. "It's important to know if living close to these roadways poses a significant risk to the developing human brain.
"If it does," Lein continues, "scientists can warn susceptible individuals, such as pregnant women -- particularly those who have already had a child diagnosed with a neurodevelopmental disorder -- to take appropriate precautions to minimize risks to the health of their child's brain."
EARLY EXPOSURE OUTCOMES
The researchers compared the brains of rat pups exposed to traffic-related air pollution with those exposed to filtered air. Both air sources were drawn from the tunnel in real time.
They found abnormal growth and increased neuroinflammation in the brains of animals exposed to air pollution. This suggests that air pollution exposure during critical developmental periods may increase the risk for changes in the developing brain that are associated with neurodevelopmental disorders.
"What we witnessed are subtle changes," Patten said. "But we are seeing these effects using air pollution exposures that fall within regulatory limits. With the backdrop of other environmental and genetic risk factors in humans, this may have a more pronounced effect. This exposure also contains very fine particulate matter that isn't currently regulated."
In a separate study, Patten extended this exposure for 14 months to look at longer-term impacts of traffic-related air pollution and is in the process of writing up those results.
The team is also interested in what component of traffic-related air pollution is driving the neurodevelopmental outcomes.
If they can identify the culprits, Lein said, then scientists can approach legislators to develop scientifically based regulations to protect the developing human brain.
TEAM EFFORTS
UC Davis atmospheric scientist and co-author Keith Bein said that the single most challenging aspect of studying the health effects of air pollution may be replicating how, when and what people are exposed to throughout their lifetimes.
Tackling this requires creative thinking and a multidisciplinary team of researchers, including exposure engineers, atmospheric scientists, toxicologists, biologists, behaviorists and animal care specialists.
"We have managed to build a unique and talented team and taken advantage of our built environment to bring us closer than we've been before to achieving these objectives," Bein said. "Increasingly, these types of efforts are required to continue advancing the field, thereby informing policymakers and stakeholders about how best to protect human health."
Other study co-authors include: Eduardo González and Anthony Valenzuela, UC Davis School of Veterinary Medicine; Elizabeth Berg, UC Davis School of Medicine; Christopher Wallis, UC Davis Air Quality Research Center; Joel Garbrow, Washington University; and Jill Silverman at the UC Davis MIND Institute and School of Medicine. The study was supported by the National Institutes of Health.
https://www.sciencedaily.com/releases/2020/06/200617145934.htm
Study finds links between early screen exposure, sleep disruption and EBD in kids
November 13, 2019
SingHealth
A new study has found that first exposure earlier than 18 months of age to screen devices -- such as smartphones, tablets, videogame consoles, television etc -- and the presence of multiple screen devices in the bedroom are associated with elevated sleep disruption and emotional and behavioural difficulties (EBD) in preschool children with neurodevelopmental disorders (NDDs)
Digital media have become an integral part of lifestyles in recent years, and the ubiquity of digital devices coupled with poor screen use habits can have a detrimental effect on the developmental and psychosocial well-being of children.
A new study by KK Women's and Children's Hospital (KKH), together with National University of Singapore, has found that first exposure earlier than 18 months of age to screen devices -- such as smartphones, tablets, videogame consoles, television etc -- and the presence of multiple screen devices in the bedroom are associated with elevated sleep disruption and emotional and behavioural difficulties (EBD) in preschool children with neurodevelopmental disorders (NDDs).
"Although this study was conducted in children with NDDs, the results from this study are applicable to the general population, and aligned with existing evidence from studies that have been done on typically developing children," said Dr Mae Wong, Senior Consultant, Department of Child Development, KKH, who led the study.
Conducted from 2015 to 2017, the study looked at 367 preschool children in Singapore aged two to five years old with NDDs such as autism, language delay, global developmental delay, and learning disorders. Using caregiver-reported information, the researchers explored the relationships between the children's screen use and sleep habits, and emotional and behavioural difficulties (EBD).
The study has been published in the Journal of Developmental & Behavioral Pediatrics.
Key study findings are outlined below, with further details in Annex A:
- Age of screen exposure -- More than half (52%) were exposed to screens / commenced screen usage at the age of 18 months or earlier.
- Screen devices in the bedroom -- More than half (57.7%) had at least one screen device in their bedrooms.
- Screen time -- Majority (93.9%) of the children exceeded the 1 hour limit of daily average screen time recommended by the American Academy of Pediatrics (AAP).
- Sleep problems -- A majority (72.3%) of children had parent-reported elevated sleep problems.
- Emotional / behavioural difficulties -- Nearly 60% (59.9%) of children had parentreported clinically elevated emotional/behavioural difficulties.
- Parental/Caregiver screen use -- Increased screen use in preschool children was associated with parents who have higher screen use themselves, and who are less likely to have house rules about screen use.
To ascertain that the sleep problems and EBDs reported did not arise from the children's ownNDDs, but were fully mediated by screen use, statistical analysis was used to control for levels of functional impairment. "Despite controlling for this, there was still a clear association between first screen exposure earlier than 18 months of age and the presence of one or more screen devices in the bedroom, with sleep problems, poorer sleep quality and more EBDs. Furthermore, children who experienced both lifestyle factors had more sleep and EBD problems than those who experienced only one lifestyle factor," said Dr Wong. Compared with typically developing children, children with NDDs are at overall higher risk for sleep problems, EBDs and poorer developmental outcomes.
"As this group of children also have more difficulties disengaging from screen use -- possibly due to the attractive and repetitive nature of the screen content -- increased screen use may possibly further exacerbate these problems," adds Dr Wong.
HOME AND FAMILY LIFESTYLE FACTORS
Earlier introduction to screen use may be related to:
- The home environment -- where shared living or study spaces where media is consumed may also function as the infant or child's sleeping area; and household lifestyle behaviours -- such as the practice of co-sleeping with family members.
- Reliance on screen devices as tools for infant or child engagement, calming or management -- while there are intermittent times (e.g., medical procedures, airplane flights) when screen devices may be useful as a soothing strategy, the continued use of screen devices to calm children may over time displace the development of the child's internal self-regulation mechanisms, perpetuating difficulties with emotional/ behavioural self-regulation and increasing reliance on screen use.
-The study found that increased screen use in preschool children was associated with parents who have higher screen use themselves, and who are less likely to have house rules about screen use.
- While there can be educational benefits from selected, age-appropriate high-quality screen use on child development and skills learning, studies have reported associations between early and sustained increased screen use, poorer language and cognitive development, and EBDs in typically developing children worldwide.
- Increased screen use over time may also further interfere with the child's sleep quality and development in a negative trajectory.
RECOMMENDATIONS FOR PARENTS AND CAREGIVERS
-Be alert to possible or detrimental health associations between poor screen use habits, sleep quality and EBDs in young children
- Make modifications to the home environment and family lifestyle to encourage regulated, interactive screen use with caregiver involvement for learning and play.
- Delay the child's first exposure to screen devices to later than 18 months of age
- Adhere to established guidelines on healthy screen use (Annex A) to mitigate the negative effects on children's sleep quality, and emotional and behavioural function and development.
https://www.sciencedaily.com/releases/2019/11/191113092608.htm
Why males are more at risk than females for neurodevelopmental disorders
New research unravels potential genetic mechanism behind this disparity
July 3, 2018
Science Daily/University of Maryland School of Medicine
Researchers have recently begun to realize that biological sex plays a key role in disease risk. Sex plays a role in hypertension, diabetes, arthritis -- and in many neurological and psychiatric disorders. Depression and anxiety affect females more, while neurodevelopmental disorders, including autism spectrum disorders, early onset schizophrenia, and attention deficit hyperactivity, affect more males. Males are also more sensitive to prenatal insults, such as gestational stress, maternal infection and drug expos
To better understand the molecular underpinnings of this disparity, Tracy Bale of the University of Maryland School of Medicine, along with several colleagues, focused on a molecule that plays a key role in placental health. In a study of mice, they found that the molecule, O-linked N-acetylglucosamine transferase (OGT) works by establishing sex-specific patterns of gene expression.
The study was published this week in the journal Nature Communications.
OGT seems to work via an epigenetic modification that broadly controls transcription, H3K27me3. Epigenetics is the study of changes in how genes are expressed. Dr. Bale showed that high levels of H3K27me3 in the female placenta produce resilience to stress experienced by the mother. This indicates at least one molecular pathway that allows females to be more resilient to maternal stress than males.
"This pathway could help explain why we see this profound neurodevelopmental difference in humans," said Dr. Bale. "OGT and H3K27me3 in the placenta are crucial to a lot of protein encoding that occurs during pregnancy, and so this process has a lot of downstream effects. The OGT gene is on the X chromosome, and seems to provide a level of protection for the female fetus to perturbations in the maternal environment."
Dr. Bale has focused much of her research on the links between stress and subsequent risk for neurodevelopmental disorders, including autism and schizophrenia in offspring. Her previous work on the placenta has found novel sex differences that may predict increased prenatal risk for disease in males.
She has previously found that, in mice, a father's stress can affect the brain development of offspring. This stress can alter the father's sperm, which can alter the brain development of the child. Dr. Bale has also found that male mice experiencing chronic mild stress have offspring with a reduced hormonal response to stress; this response has been linked to some neuropsychiatric disorders, including PTSD. This suggests that even mild environmental challenges can have a significant effect on the health of offspring.
https://www.sciencedaily.com/releases/2018/07/180703141329.htm