Air pollution's connection to infant mortality

June 29, 2020

Science Daily/Stanford University

The study of sub-Saharan Africa finds that a relatively small increase in airborne particles significantly increase infant mortality rates. A cost-effective solution may lie in an exotic-sounding proposal.

Dust sweeping across the Southeast U.S. in recent days warns of a growing risk to infants and children in many parts of the world. A Stanford-led study focuses on this dust, which travels thousands of miles from the Sahara Desert, to paint a clearer picture than ever before of air pollution's impact on infant mortality in sub-Saharan Africa. The paper, published June 29 in Nature Sustainability, reveals how a changing climate might intensify or mitigate the problem, and points to seemingly exotic solutions to reducing dust pollution that could be more effective and affordable than current health interventions in improving child health.

"Africa and other developing regions have made remarkable strides overall in improving child health in recent decades, but key negative outcomes such as infant mortality remain stubbornly high in some places," said study senior author Marshall Burke, an associate professor of Earth system science in Stanford's School of Earth, Energy & Environmental Sciences. "We wanted to understand why that was, and whether there was a connection to air pollution, a known cause of poor health."

Understanding airborne danger

Children under 5 are particularly vulnerable to the tiny particles, or particulate, in air pollution that can have a range of negative health impacts, including lower birth weight and impaired growth in the first year of life. In developing regions, exposure to high levels of air pollution during childhood is estimated to reduce overall life expectancy by 4-5 years on average.

Quantifying the health impacts of air pollution -- a crucial step for understanding global health burdens and evaluating policy choices -- has been a challenge in the past. Researchers have struggled to adequately separate out the health effects of air pollution from the health effects of activities that generate the pollution. For example, a booming economy can produce air pollution but also spur developments, such as lower unemployment, that lead to better healthcare access and improved health outcomes.

To isolate the effects of air pollution exposure, the Stanford-led study focuses on dust carried thousands of miles from the Bodélé Depression in Chad -- the largest source of dust emissions in the world. This dust is a frequent presence in West Africa and, to a lesser extent, across other African regions. The researchers analyzed 15 years of household surveys from 30 countries across Sub-Saharan Africa covering nearly 1 million births. Combining birth data with satellite-detected changes in particulate levels driven by the Bodélé dust provided an increasingly clear picture of poor air quality's health impacts on children.

Sobering findings and surprising solutions

The researchers found that a roughly 25 percent increase in local annual mean particulate concentrations in West Africa causes an 18 percent increase in infant mortality. The results expand on a 2018 paper by the same researchers that found exposure to high particulate matter concentrations in sub-Saharan Africa accounted for about 400,000 infant deaths in 2015 alone.

The new study, combined with previous findings from other regions, makes clear that air pollution, even from natural sources, is a "critical determining factor for child health around the world," the researchers write. Emissions from natural sources could change dramatically in a changing climate, but it's unclear how. For example, the concentration of dust particulate matter across Sub-Saharan Africa is highly dependent on the amount of rainfall in the Bodélé Depression. Because future changes in rainfall over the Bodélé region due to climate change are highly uncertain, the researchers calculated a range of possibilities for sub-Saharan Africa that could result in anywhere from a 13-percent decline in infant mortality to a 12-percent increase just due to changes in rainfall over the desert. These impacts would be larger than any other published projections for climate change impact on health across Africa.

Safeguarding children against air pollution is nearly impossible in many developing regions because many homes have open windows or permeable roofs and walls, and infants and young children are unlikely to wear masks. Instead, the researchers suggest exploring the possibility of dampening sand with groundwater in the Bodélé region to stop it from going airborne -- an approach that has been successful at small scale in California.

The researchers estimate that deploying solar-powered irrigation systems in the desert area could avert 37,000 infant deaths per year in West Africa at a cost of $24 per life, making it competitive with many leading health interventions currently in use, including a range of vaccines and water and sanitation projects.

"Standard policy instruments can't be counted on to reduce all forms of air pollution," said study lead author Sam Heft-Neal, a research scholar at Stanford's Center on Food Security and the Environment. "While our calculation doesn't consider logistical constraints to project deployment, it highlights the possibility of a solution that targets natural pollution sources and yields enormous benefits at a modest cost."

https://www.sciencedaily.com/releases/2020/06/200629120215.htm

Wildfire smoke has immediate harmful health effects

June 24, 2020

Science Daily/University of British Columbia

Exposure to wildfire smoke affects the body's respiratory and cardiovascular systems almost immediately, according to new research from the University of British Columbia's School of Population and Public Health.

In a study published today in Environmental Health Perspectives, researchers found that exposure to elevated levels of fine particulate matter during wildfire seasons in British Columbia was associated with increased odds of ambulance dispatches related to respiratory and cardiovascular conditions, with increased ambulance dispatches occurring within only one hour after exposure. Among people with diabetes, the researchers found that the odds of health complications increased within 48 hours following exposure to wildfire smoke.

"We have long known about the harmful health effects of wildfire smoke," says Jiayun Angela Yao, the study's lead author who conducted this research while completing her PhD in the UBC School of Population and Public Health. "But it's alarming to see just how quickly fine particular matter seems to affect the respiratory and cardiovascular system. And the acute effects for people with diabetes is relatively new to us."

Particulate matter, also called particle pollution, is made up of tiny pieces of dust, dirt, and smoke in the air. While larger particles can irritate the eyes and throat, fine particles are more dangerous as they can reach deep parts of the lungs and even enter the bloodstream.

For the study, the researchers used statistical modelling to evaluate the relationship between ambulance dispatches, paramedic assessments and hospital admissions related to respiratory, circulatory and diabetic conditions with levels of fine particulate matter during wildfire seasons in B.C. from 2010 to 2015. A total of more than 670,000 ambulance dispatch calls from more than 500,000 individuals were included in the study.

The researchers say this study adds to the limited previous evidence on how quickly exposure to wildfire smoke can have harmful health effects. The findings are especially timely now during the COVID-19 pandemic, as air pollution from wildfire smoke can make viral infections affecting the respiratory and cardiovascular systems even more severe.

With wildfire season quickly approaching in B.C., the researchers say their research underscores the need for rapid public health actions to limit exposure to wildfire smoke.

"It is vital that everyone start preparing for wildfire smoke events to ensure that they are ready, especially since COVID-19 still a serious public health threat in B.C.," says Yao. "Anyone with pre-existing heart and lung disease and diabetes is especially vulnerable and should consider purchasing air cleaners, and ensuring that they have adequate supplies of medication at home."

This study was supported by the Australian Research Council Linkage Program and the British Columbia Lung Association.

https://www.sciencedaily.com/releases/2020/06/200624100045.htm

High air pollution exposure in 1-year-olds linked to structural brain changes at age 12

January 24, 2020

Science Daily/Cincinnati Children's Hospital Medical Center

A new study suggests that significant early childhood exposure to traffic-related air pollution (TRAP) is associated with structural changes in the brain at the age of 12.

The Cincinnati Children's Hospital Medical Center study found that children with higher levels of TRAP exposure at birth had reductions at age 12 in gray matter volume and cortical thickness as compared to children with lower levels of exposure.

"The results of this study, though exploratory, suggest that where you live and the air you breathe can affect how your brain develops, says Travis Beckwith, PhD, a research fellow at Cincinnati Children's and lead author of the study. "While the percentage of loss is far less than what might be seen in a degenerative disease state, this loss may be enough to influence the development of various physical and mental processes."

Gray matter includes regions of the brain involved in motor control as well as sensory perception, such as seeing and hearing. Cortical thickness reflects the outer gray matter depth. The study found that specific regions in the frontal and parietal lobes and the cerebellum were affected with decreases on the order of 3 to 4 percent.

"If early life TRAP exposure irreversibly harms brain development, structural consequences could persist regardless of the time point for a subsequent examination," says Dr. Beckwith.

The researchers on the study, which is published online in PLOS One, used magnetic resonance imaging to obtain anatomical brain images from 147 12 year olds. These children are a subset of the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS), which recruited volunteers prior to the age of six months to examine early childhood exposure to TRAP and health outcomes.

The volunteers in the CCAAPS had either high or low levels of TRAP exposure during their first year of life. The researchers estimated exposure using an air sampling network of 27 sites in the Cincinnati area, and 24/7 sampling was conducted simultaneously at four or five sites over different seasons. Participating children and their caregivers completed clinic visits at ages 1, 2, 3, 4, 7 and 12.

Previous studies of TRAP suggest that it contributes to neurodegenerative diseases and neurodevelopmental disorders. This work supports that TRAP changes brain structure early in life.

https://www.sciencedaily.com/releases/2020/01/200124155107.htm

Mix of stress and air pollution may lead to cognitive difficulties in children

January 16, 2020

Science Daily/Columbia University's Mailman School of Public Health

Children with elevated exposure to early life stress in the home and elevated prenatal exposure to air pollution exhibited heightened symptoms of attention and thought problems, according to researchers at Columbia University Mailman School of Public Health and Columbia Psychiatry. Early life stress is common in youth from disadvantaged backgrounds who also often live in areas with greater exposure to air pollution.

Air pollution has negative effects on physical health, and recent work has begun to also show negative effects on mental health. Life stress, particularly early in life, is one of the best-known contributors to mental health problems. The new study is one of the first to examine the combined effects of air pollution and early life stress on school-age children. Results appear in the Journal of Child Psychology and Psychiatry.

"Prenatal exposure to polycyclic aromatic hydrocarbons, a neurotoxicant common in air pollution, seems to magnify or sustain the effects of early life social and economic stress on mental health in children," says first author David Pagliaccio, PhD, assistant professor of clinical neurobiology in psychiatry at Columbia Psychiatry.

"Air pollutants are common in our environment, particularly in cities, and given socioeconomic inequities and environmental injustice, children growing up in disadvantaged circumstances are more likely to experience both life stress and exposure to neurotoxic chemicals," says senior author Amy Margolis, PhD, assistant professor of medical psychology in psychiatry at Columbia Psychiatry.

"These exposures have a combined effect on poor mental health outcomes and point to the importance of public health programs that try to lessen exposure to these critical risk factors, to improve not only physical, but psychological health," says Julie Herbstman, PhD, associate professor of environmental health science and director of the Columbia Center for Children's Environmental Health at Columbia Mailman School of Public Health.

Data were from the CCCEH Mothers and Newborns longitudinal birth cohort study in Northern Manhattan and the Bronx, which includes many participants who self-identify as African American or Dominican. Mothers wore an air monitoring backpack during the third trimester of pregnancy to measure exposure to air pollutants in their daily lives. When their children were 5 years old, mothers reported on stress in their lives, including neighborhood quality, material hardship, intimate partner violence, perceived stress, lack of social support, and general distress levels. Mothers then reported on their child's psychiatric symptoms at ages 5, 7, 9 and 11.

The combined effect of air pollution and early life stress was seen across several measures of thought and attention problems/ADHD at age 11. (Thought problems included obsessive thoughts and behaviors or thoughts that others find strange.) The effects were also linked to PAH-DNA adducts -- a dose-sensitive marker of air pollution exposure.

The researchers say PAH and early life stress may serve as a "double hit" on shared biological pathways connected to attention and thought problems. Stress likely leads to wide-ranging changes in, for example, epigenetic expression, cortisol, inflammation, and brain structure and function. The mechanism underlying the effects of PAH is still being interrogated; however, alterations in brain structure and function represent possible shared mechanistic pathways.

Earlier studies making use of the same longitudinal cohort data found that prenatal exposure to air pollution combines with material hardship to significantly increase ADHD symptoms in children. A separate study found a combination of air pollution and poverty lowered child IQ.

https://www.sciencedaily.com/releases/2020/01/200116155436.htm

Air pollution in childhood linked to schizophrenia

January 7, 2020

Science Daily/Aarhus University

Air pollution affects physical health, and research results now conclude that it also affects our psychological health. The study, which combines genetic data from iPSYCH with air pollution data from the Department of Environmental Science, shows that children who are exposed to a high level of air pollution while growing up, have an increased risk of developing schizophrenia.

"The study shows that the higher the level of air pollution, the higher the risk of schizophrenia. For each 10 ?g/m3 (concentration of air pollution per cubic metre) increase in the daily average, the risk of schizophrenia increases by approximately twenty per cent. Children who are exposed to an average daily level above 25 ?g/m3 have an approx. sixty per cent greater risk of developing schizophrenia compared to those who are exposed to less than 10 ?g/m3," explains Senior Researcher Henriette Thisted Horsdal, who is behind the study.

To put these figures into perspective, the lifetime risk of developing schizophrenia is approximately two per cent, which equates to two out of a hundred people developing schizophrenia during their life. For people exposed to the lowest level of air pollution, the lifetime risk is just under two per cent, while the lifetime risk for those exposed to the highest level of air pollution is approx. three per cent.

Unknown cause

The results of the study have just been published in the scientific journal JAMA Network Open.

"The risk of developing schizophrenia is also higher if you have a higher genetic liability for the disease. Our data shows that these associations are independent of each other. The association between air pollution and schizophrenia cannot be explained by a higher genetic liability in people who grow up in areas with high levels of air pollution," says Henriette Thisted Horsdal about the study, which is the first of its kind to combine air pollution and genetics in relation to the risk of developing schizophrenia.

The study included 23,355 people in total, and of these, 3,531 developed schizophrenia. Though the results demonstrate an increased risk of schizophrenia when the level of air pollution during childhood increases, the researchers cannot comment on the cause. Instead they emphasise that further studies are needed before they can identify the cause of this association.

https://www.sciencedaily.com/releases/2020/01/200107104913.htm

Air pollution's tiny particles may trigger nonfatal heart attacks

February 14, 2020

Science Daily/Yale School of Public Health

Yale-affiliated scientist finds that even a few hours' exposure to ambient ultrafine particles common in air pollution may potentially trigger a nonfatal heart attack.

Myocardial infarction is a major form of cardiovascular disease worldwide. Ultrafine particles (UFP) are 100 nanometers or smaller in size. In urban areas, automobile emissions are the primary source of UFP.

The study in the journal Environmental Health Perspectives is believed to be the first epidemiological investigation of the effects of UFP exposure and heart attacks using the number of particles and the particle length and surface area concentrations at hourly intervals of exposure.

"This study confirms something that has long been suspected -- air pollution's tiny particles can play a role in serious heart disease. This is particularly true within the first few hours of exposure," said Kai Chen, Ph.D., assistant professor at Yale School of Public Health and the study's first author. "Elevated levels of UFP are a serious public health concern."

UFP constitute a health risk due to their small size, large surface areas per unit of mass, and their ability to penetrate the cells and get into the blood system. "We were the first to demonstrate the effects of UFP on the health of asthmatics in an epidemiological study in the 1990s," said Annette Peters, director of the Institute of Epidemiology at Helmholtz Center Munich and a co-author of this paper. "Since then approximately 200 additional studies have been published. However, epidemiological evidence remains inconsistent and insufficient to infer a causal relationship."

The lack of consistent findings across epidemiological studies may be in part because of the different size ranges and exposure metrics examined to characterize ambient UFP exposure. Chen and his co-authors were interested in whether transient UFP exposure could trigger heart attacks and whether alternative metrics such as particle length and surface area concentrations could improve the investigation of UFP-related health effects.

With colleagues from Helmholtz Center Munich, Augsburg University Hospital and Nördlingen Hospital, Chen examined data from a registry of all nonfatal MI cases in Augsburg, Germany. The study looked at more than 5, 898 nonfatal heart attack patients between 2005 and 2015. The individual heart attacks were compared against air pollution UFP data on the hour of the heart attack and adjusted for a range of additional factors, such as the day of the week, long-term time trend and socioeconomic status.

"This represents an important step toward understanding the appropriate indicator of ultrafine particles exposure in determining the short-term health effects, as the effects of particle length and surface concentrations were stronger than the ones of particle number concentration and remained similar after adjustment for other air pollutants," said Chen. "Our future analyses will examine the combined hourly exposures to both air pollution and extreme temperature. We will also identify vulnerable subpopulations regarding pre-existing diseases and medication intake."

https://www.sciencedaily.com/releases/2020/02/200214134717.htm

Is pollution linked to psychiatric disorders?

August 20, 2019

Science Daily/PLOS

Researchers are increasingly studying the effects of environmental insults on psychiatric and neurological conditions, motivated by emerging evidence from environmental events like the record-breaking smog that choked New Delhi two years ago. The results of a new study publishing August 20 in the open-access journal PLOS Biology by an international group of researchers using large data sets from the US and Denmark suggests a possible link between exposure to environmental pollution and an increase in the prevalence of psychiatric disorders.

The team found that poor air quality was associated with higher rates of bipolar disorder and major depression in both US and Danish populations. The trend appeared even stronger in Denmark, where exposure to polluted air during the first ten years of a person's life also predicted a more than two-fold increase in schizophrenia and personality disorders.

"Our study shows that living in polluted areas, especially early on in life, is predictive of mental disorders in both the United States and Denmark," said computational biologist Atif Khan, the first author of the new study. "The physical environment -- in particular air quality -- warrants more research to better understand how our environment is contributing to neurological and psychiatric disorders."

Although mental illnesses like schizophrenia develop due to a complex interplay of genetic predispositions and life experiences or exposures, genetics alone do not account entirely for variations in mental health and disease. Researchers have long suspected that genetic, neurochemical and environmental factors interact at different levels to affect the onset, severity and progression of these illnesses.

Growing evidence is beginning to provide insight into how components of air pollution can be toxic to the brain: Recent studies on rodents suggest that environmental agents like ambient small particulate matter (fine dust) travel to the brain through the nose and lungs, while animals exposed to pollution have also shown signs of cognitive impairment and depression-like behavioral symptoms. "We hypothesized that pollutants might affect our brains through neuroinflammatory pathways that have also been shown to cause depression-like signs in animal studies," said Andrey Rzhetsky, who led the new study.

To quantify air pollution exposure among individuals in the United States, the University of Chicago team relied on the US Environmental Protection Agency's measurements of 87 air quality measurements. For individuals in Denmark, they used a national pollution register that tracked a smaller number of pollutants with much higher spatial resolution.

The researchers then examined two population data sets, the first being a U.S. health insurance claims database that included 11 years of claims for 151 million individuals. The second dataset consisted of all 1.4 million individuals born in Denmark from 1979 through 2002 who were alive and residing in Denmark at their tenth birthday. Because Danes are assigned unique identification numbers that can link information from various national registries, the researchers were able to estimate exposure to air pollution at the individual level during the first ten years of their life. In the US study, exposure measurements were limited to the county level. "We strived to provide validation of association results in independent large datasets," said Rzhetsky.

The findings have not been without controversy. "This study on psychiatric disorders is counterintuitive and generated considerable resistance from reviewers," said Rzhetsky. Indeed, the divided opinions of the expert reviewers prompted PLOS Biology to commission a special companion article from Prof. John Ioannidis of Stanford University (Ioannidis is unconnected with the study, but assisted the journal with the editorial process).

"A causal association of air pollution with mental diseases is an intriguing possibility. Despite analyses involving large datasets, the available evidence has substantial shortcomings and a long series of potential biases may invalidate the observed associations," says Ioannidis in his commentary. "More analyses by multiple investigators, including contrarians, are necessary."

Rzhetsky also cautioned that the significant associations between air pollution and psychiatric disorders discovered in the study do not necessarily mean causation, and said that further research is needed to assess whether any neuroinflammatory impacts of air pollution share common pathways with other stress-induced conditions.

https://www.sciencedaily.com/releases/2019/08/190820141604.htm

Exposure to air pollution before and after birth may affect fundamental cognitive abilities

May 23, 2019

Science Daily/Barcelona Institute for Global Health (ISGlobal)

A growing body of research suggests that exposure to air pollution in the earliest stages of life is associated with negative effects on cognitive abilities. A new study led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by "la Caixa," has provided new data: exposure to particulate matter with a diameter of less than 2.5 μm (PM2.5) during pregnancy and the first years of life is associated with a reduction in fundamental cognitive abilities, such as working memory and executive attention.

The study, carried out as part of the BREATHE project, has been published in Environmental Health Perspectives. The objective was to build on the knowledge generated by earlier studies carried out by the same team, which found lower levels of cognitive development in children attending schools with higher levels of traffic-related air pollution.

The study included 2,221 children between 7 and 10 years of age attending schools in the city of Barcelona. The children's cognitive abilities were assessed using various computerized tests. Exposure to air pollution at home during pregnancy and throughout childhood was estimated with a mathematical model using real measurements.

The study found that greater PM2.5 exposure from pregnancy until age 7 years was associated with lower working memory scores on tests administered between the ages of 7 and 10 years. The results suggest that exposure to fine particulate matter throughout the study period had a cumulative effect, although the associations were stronger when the most recent years of exposure were taken into account. Working memory is a cognitive system responsible for temporarily holding information for subsequent manipulation. It plays a fundamental role in learning, reasoning, problem-solving and language comprehension.

Sex-stratified analysis showed that the relationship between PM2.5 exposure and diminished working memory was found only in boys. "As yet, we don't understand what causes these differences, but there are various hormonal and genetic mechanisms that could lead to girls having a better response to inflammatory processes triggered by fine particulate matter and being less susceptible to the toxicity of these particles," commented Ioar Rivas, ISGlobal researcher and lead author of the study.

The study also found that higher exposure to particulate matter was associated with a reduction in executive attention in both boys and girls. Executive attention is one of the three networks that make up a person's attention capacity. It is involved in high-level forms of attention, such as the detection and resolution of conflicts between options and responses, error detection, response inhibition, and the regulation of thoughts and feelings.

Whereas previous studies in the BREATHE project analysed exposure to air pollution at schools over the course of a year, this study assessed exposures at the participants' homes over a much longer time: from the prenatal period to 7 years of age.

"This study reinforces our previous findings and confirms that exposure to air pollution at the beginning of life and throughout childhood is a threat to neurodevelopment and an obstacle that prevents children from reaching their full potential," commented Jordi Sunyer, Childhood and Environment Programme Coordinator at ISGlobal and last author of the study.

https://www.sciencedaily.com/releases/2019/05/190523104925.htm

Air pollution and noise increase risk for heart attacks

October 24, 2018

Science Daily/Swiss Tropical and Public Health Institute

Air pollution and transportation noise are both associated with an increased risk of heart attacks. Studies on air pollution, which do not take into account traffic noise, tend to overestimate the long-term effect of air pollution on heart attacks.

Where air pollution is high, the level of transportation noise is usually also elevated. Not only air pollution negatively impacts on health, but also car, train and aircraft noise increases the risk for cardiovascular diseases and diabetes, as previous research has demonstrated. Studies investigating the effect of air pollution without sufficiently taking into account the impact that noise exhibits on health, might overestimate the effect of air pollution. These are the results of a comprehensive study conducted by the Swiss Tropical and Public Health Institute (Swiss TPH), which was published today in the peer-reviewed European Heart Journal.

The study looked at the combined effects of air pollution and transportation noise for heart attack mortality, by considering all deaths that occurred in Switzerland between 2000 and 2008. Analyses that only included fine particulates (PM2.5) suggest that the risk for a heart attack rises by 5.2% per 10 ?g/m³ increase in the long-term concentration at home. Studies which also account for road, railway and aircraft noise reveal that the risk for a heart attack attributable to fine particulates in fact increases considerably less; 1.9% per 10 ?g/m³ increase. These findings indicate that the negative effects of air pollution may have been overestimated in studies which fail to concurrently consider noise exposure.

"Our study showed that transportation noise increases the risk for a heart attack by 2.0 to 3.4% per 10 decibels increase in the average sound pressure level at home." said Martin Röösli, Head of the Environmental Exposures and Health Unit at Swiss TPH, and lead author of the published research. "Strikingly, the effects of noise were independent from air pollution exposure."

Effect of noise and air pollution are additive

The study also found that people exposed to both air pollution and noise are at highest risk of heart attack. Hence, the effects of air pollution and noise are additive. "Public discussions often focus on the negative health effects of either air pollution or noise but do not consider the combined impact." said Röösli. "Our research suggests that both exposures must be considered at the same time." This has implications for both policy as well as future research. Hence, Röösli and co-researchers recommend including transportation noise exposure in any further research related to air pollution and health to avoid overestimating the negative effects of air pollution on the cardiovascular system.

Data from across Switzerland

The study included all deaths (19,261) reported across Switzerland from the period 2000 to 2008. The air pollution (PM2.5) was modelled using satellite and geographic data, calibrated with air pollution measurements from 99 measurement sites throughout Switzerland. Nitrogen dioxides (NO2) were also modelled using 9,469 biweekly passive sampling measurements collected between 2000 and 2008 at 1,834 locations in Switzerland. Transportation noise was modelled by well-established noise propagation models (sonRoad, sonRAIL and FLULA 2) by Empa and n-sphere. The air pollution and the transportation noise models were applied for each address of the 4.4 million Swiss adult citizen (aged 30 years and above).

https://www.sciencedaily.com/releases/2018/10/181024112244.htm

Exposure to air pollution in pregnancy does not increase symptoms of attention-deficit

June 25, 2018

Science Daily/Barcelona Institute for Global Health (ISGlobal)

A study of 30,000 children from seven European countries found no association between prenatal exposure to air pollution and symptoms of attention-deficit and hyperactivity.

Exposure to air pollution during pregnancy may not be associated with an increased risk of attention-deficit and hyperactivity symptoms in children aged 3 to 10 years. This was the conclusion of a new study led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by the "la Caixa" Banking Foundation. The study included data on nearly 30,000 children from seven European countries.

With a worldwide prevalence of 5%, ADHD is the most common childhood behavioural disorder. ADHD is characterized by a pattern of inattention, hyperactivity and/or impulsivity that is atypical for the child's age. These symptoms can interfere with development and have been associated with academic problems in school-aged children as well as an increased risk of problems with addiction or risky behaviours.

Recent studies have concluded that prenatal exposure to air pollution could affect brain development in children, but the evidence on the effects of air pollution on ADHD symptoms is limited.

The new study, published in the journal Epidemiology, forms part of the European Study of Cohorts for Air Pollution Effects (ESCAPE). It included 30,000 children between 3 and 10 years of age from eight birth cohorts in Germany, Denmark, France, Italy, the Netherlands, Sweden and Spain (the latter consisting of four sub-cohorts from the INMA project in Gipuzkoa, Granada, Sabadell and Valencia). The study estimated exposures to nitrogen oxides (NOx) and particulate matter (PM10 and PM2.5) throughout pregnancy at each participant's home address. ADHD symptoms were assessed using various questionnaires completed by parents and/or teachers.

Joan Forns, lead author of the study, commented: "Our findings show no association between exposure to air pollution during pregnancy and increased risk of ADHD symptoms."

"Given the conclusions of this study and the inconsistent findings of previous studies, we hypothesise that exposure to air pollution might not increase the risk of ADHD in children in the general population," explained ISGlobal researcher Mònica Guxens, who coordinated the study. "However, we believe that exposure to air pollution could have harmful effects on neuropsychological development, especially in genetically susceptible children."

It has been shown that ADHD is the result of complex interactions between genetic background (heritability is approximately 75%), environmental factors and social determinants. "We will continue to study the role of air pollution in order to rule out its association with childhood ADHD and improve our understanding of what causes this disorder," said Guxens.

https://www.sciencedaily.com/releases/2018/06/180625122348.htm

How toxic air clouds mental health

November 2, 2017

Science Daily/University of Washington

Researchers have found a link between air pollution and psychological distress. The higher the level of particulates in the air, the study showed, the greater the impact on mental health. The study is believed to be the first to use a nationally representative survey pool, cross-referenced with pollution data at the census block level, to evaluate the connection between toxic air and mental health.

There is little debate over the link between air pollution and the human respiratory system: Research shows that dirty air can impair breathing and aggravate various lung diseases. Other potential effects are being investigated, too, as scientists examine connections between toxic air and obesity, diabetes and dementia.

Now add to that list psychological distress, which University of Washington researchers have found is also associated with air pollution. The higher the level of particulates in the air, the UW-led study showed, the greater the impact on mental health.

The study, published in the November issue of Health & Place, is believed to be the first to use a nationally representative survey pool, cross-referenced with pollution data at the census block level, to evaluate the connection between toxic air and mental health.

"This is really setting out a new trajectory around the health effects of air pollution," said Anjum Hajat, an assistant professor of epidemiology in the UW School of Public Health. "The effects of air pollution on cardiovascular health and lung diseases like asthma are well established, but this area of brain health is a newer area of research."

Where a person lives can make a big difference to health and quality of life. Scientists have identified "social determinants" of physical and mental well-being, such as availability of healthy foods at local grocers, access to nature or neighborhood safety.

Air pollution, too, has been associated with behavior changes -- spending less time outside, for instance, or leading a more sedentary lifestyle -- that can be related to psychological distress or social isolation.

The UW study looked for a direct connection between toxic air and mental health, relying on some 6,000 respondents from a larger, national, longitudinal study, the Panel Study of Income Dynamics. Researchers then merged an air pollution database with records corresponding to the neighborhoods of each of the 6,000 survey participants. The team zeroed in on measurements of fine particulate matter, a substance produced by car engines, fireplaces and wood stoves, and power plants fueled by coal or natural gas. Fine particulate matter (particles less than 2.5 micrometers in diameter) is easily inhaled, can be absorbed into the bloodstream and is considered of greater risk than larger particles. (To picture just how small fine particulate matter is, consider this: The average human hair is 70 micrometers in diameter.)

The current safety standard for fine particulates, according to the U.S. Environmental Protection Agency, is 12 micrograms per cubic meter. Between 1999 and 2011, the time frame examined in the UW study, survey respondents lived in neighborhoods where fine particulates measured anywhere from 2.16 to 24.23 micrograms per cubic meter, with an average level of 11.34.

The survey questions relevant to the UW study gauged participants' feelings of sadness, nervousness, hopelessness and the like and were scored with a scale that assesses psychological distress.

The UW study found that the risk of psychological distress increased alongside the amount of fine particulate matter in the air. For example, in areas with high levels of pollution (21 micrograms per cubic meter), psychological distress scores were 17 percent higher than in areas with low levels of pollution (5 micrograms per cubic meter). Another finding: Every increase in pollution of 5 micrograms per cubic meter had the same effect as a 1.5-year loss in education.

Researchers controlled for other physical, behavioral and socioeconomic factors that can influence mental health, such as chronic health conditions, unemployment and excessive drinking.

But some patterns emerged that warrant more study, explained primary author Victoria Sass, a graduate student in the Department of Sociology.

When the data are broken down by race and gender, black men and white women show the most significant correlation between air pollution and psychological distress: The level of distress among black men, for instance, in areas of high pollution, is 34 percent greater than that of white men, and 55 percent greater than that of Latino men. A noticeable trend among white women is the substantial increase in distress -- 39 percent -- as pollution levels rise from low to high.

Precisely why air pollution impacts mental health, especially among specific populations, was beyond the scope of the study, Sass said. But that's what makes further research important.

"Our society is segregated and stratified, which places an unnecessary burden on some groups," Sass said. "Even moderate levels can be detrimental to health."

Air pollution, however, is something that can be mitigated, Hajat said, and has been declining in the United States. It's a health problem with a clear, actionable solution. But it requires the political will to continue to regulate air quality, Sass added.

"We shouldn't think of this as a problem that has been solved," she said. "There is a lot to be said for having federal guidelines that are rigorously enforced and continually updated. The ability of communities to have clean air will be impacted with more lax regulation."

https://www.sciencedaily.com/releases/2017/11/171102121128.htm

Fine particulate air pollution linked with increased autism risk

December 18, 2014

Science Daily/Harvard School of Public Health

Women exposed to high levels of fine particulate matter specifically during pregnancy -- particularly during the third trimester -- may face up to twice the risk of having a child with autism than mothers living in areas with low particulate matter, according to a study. The greater the exposure, the greater the risk, researchers found. It was the first US-wide study exploring the link between airborne particulate matter and autism.

"Our data add additional important support to the hypothesis that maternal exposure to air pollution contributes to the risk of autism spectrum disorders," said Marc Weisskopf, associate professor of environmental and occupational epidemiology and senior author of the study. "The specificity of our findings for the pregnancy period, and third trimester in particular, rules out many other possible explanations for these findings."

The researchers explored the association between autism and exposure to PM2.5 before, during, and after pregnancy. They also calculated exposure to PM2.5 during each pregnancy trimester.

Exposure to PM2.5 was significantly associated with autism during pregnancy, but not before or after, the study found. And during the pregnancy, the third trimester specifically was significantly associated with an increased risk. Little association was found between air pollution from larger-sized particles (PM10-2.5) and autism.

"The evidence base for a role for maternal exposure to air pollution increasing the risk of autism spectrum disorders is becoming quite strong," said Weisskopf. "This not only gives us important insight as we continue to pursue the origins of autism spectrum disorders, but as a modifiable exposure, opens the door to thinking about possible preventative measures."

http://www.sciencedaily.com/releases/2014/12/141218081334.htm

Air pollution linked to learning and memory problems, depression

July 6, 2011

Science Daily/Ohio State University

Long-term exposure to air pollution can lead to physical changes in the brain, as well as learning and memory problems and even depression, new research in mice suggests. While other studies have shown the damaging effects of polluted air on the heart and lungs, this is one of the first long-term studies to show the negative impact on the brain.

While other studies have shown the damaging effects of polluted air on the heart and lungs, this is one of the first long-term studies to show the negative impact on the brain, said Laura Fonken, lead author of the study and a doctoral student in neuroscience at Ohio State University.

"The results suggest prolonged exposure to polluted air can have visible, negative effects on the brain, which can lead to a variety of health problems," Fonken said. "This could have important and troubling implications for people who live and work in polluted urban areas around the world."

In other studies, several of the co-authors of this study from the Davis research center found that chronic exposure to polluted air leads to widespread inflammation in the body, which is linked to a variety of health problems in humans, including depression. This new study found evidence that this low-grade inflammation is evident in the hippocampus.

http://www.sciencedaily.com/releases/2011/07/110705071735.htm

Air pollution may disrupt sleep

May 22, 2017

Science Daily/American Thoracic Society

High levels of air pollution over time may get in the way of a good night's sleep, according to new research.

"Prior studies have shown that air pollution impacts heart health and affects breathing and lung function, but less is known about whether air pollution affects sleep," said lead author Martha E. Billings, MD, MSc, assistant professor of medicine at the University of Washington. "We thought an effect was likely given that air pollution causes upper airway irritation, swelling and congestion, and may also affect the central nervous system and brain areas that control breathing patterns and sleep."

The researchers analyzed data from 1,863 participants (average age 68) in the Multi-Ethnic Study of Atherosclerosis (MESA) who also enrolled in both MESA's Sleep and Air Pollution studies. The researchers looked at two of the most common air pollutants: NO2 (traffic-related pollutant gas) and PM2.5, or fine-particle pollution. Using air pollution measurements gathered from hundreds of MESA Air and Environmental Protection Agency monitoring sites in six U.S. cities, plus local environment features and sophisticated statistical tools, the research team was able to estimate air pollution exposures at each participant's home at two time points: one year and five years.

Wrist actigraphy, which measures small movements, provided detailed estimates of sleep and wake patterns over seven consecutive days. This was used to calculate "sleep efficiency" -- a measure of the percentage of time in bed spent asleep vs. awake. Researchers found that the sleep efficiency of the lowest 25 percent of participants was 88 percent or less. The research team studied if pollution exposures differed among those in this low sleep efficiency group.

The population was divided into "fourths" according to levels of pollution. The quarter of those who experienced the highest levels of pollution was compared to the quarter with the lowest levels.

The study found:

The group with the highest levels of NO2 over five years had an almost 60 percent increased likelihood of having low sleep efficiency compared to those with the lowest NO2 levels. The group with the highest exposures to small particulates (PM2.5) had a nearly 50 percent increased likelihood of having low sleep efficiency.

The authors adjusted for a range of factors, including age, body mass, obstructive sleep apnea, race/ethnicity, income and smoking status. They also adjusted for neighborhood socioeconomic status.

The researchers were particularly interested in chronic exposure to air pollution and what that long-term exposure might mean for sleep health. "There may be acute sleep effects to short-term exposure to high pollution levels as well, but we lacked the data to study that link," Dr. Billings said, noting that the parent MESA study is investigating the chronic effects of air pollution on cardiovascular health.

"These new findings indicate the possibility that commonly experienced levels of air pollution not only affect heart and lung disease, but also sleep quality. Improving air quality may be one way to enhance sleep health and perhaps reduce health disparities," Dr. Billings said.

Future studies, she added, need to explore the association between other air pollutants and sleep, the mechanisms by which these pollutants may disrupt sleep patterns and whether traffic noise is the driving factor contributing to poor sleep quality.

https://www.sciencedaily.com/releases/2017/05/170522080830.htm