Air pollution

NEW US research has found that growing up in a city with a high level of air pollution could increase the risk of Alzheimer’s disease and progression of the disease.

Carried out by researchers at the University of Montana, the study looked at the effects of air pollution in Mexico City, where 24 million people in the metropolitan area are exposed daily to concentrations of fine particulate matter (PM2.5) and ozone pollution above US Environmental Protection Agency standards.

The team looked at 203 autopsies of Mexico City residents, who ranged in age from 11 months to 40 years, to measure the levels of two abnormal proteins which indicate the development of Alzheimer’s – hyperphosphorylated tau and beta amyloid.

The results showed that 99.5% of the subjects examined showed signs of Alzheimer’s disease, with the early stages of the disease even found in babies less than a year old.

The young adult city dwellers, who had had a lifetime of exposure to PM2.5, also showed high levels of both proteins in the brain.

In addition to the proteins tau and amyloid, the team also looked at the gene apolipoprotein E (APOE 4), which is a well-known risk factor for Alzheimer’s.

This time the team found that not only was the progression of Alzheimer’s related to age and PM2.5 exposure, but it was also linked with APOE 4, with APOE 4 carriers showing a higher risk of rapid progression of the disease as well as 4.92 higher odds of committing suicide compared to those who don’t carry the gene.

The team concluded that exposure to PM2.5 had a negative effect on the progression of the disease due to the tiny pollution particles entering the brain through the nose, lungs and gastrointestinal tract from where they can travel everywhere in the body through the circulatory system causing damage.

They added in their conclusion that air pollution is one of the key modifiable risk for millions of people across the world, including millions exposed to harmful particulate pollution levels.

“Alzheimer’s disease hallmarks start in childhood in polluted environments, and we must implement effective preventative measures early,” said lead researcher Dr Lilian Calderón-Garcidueñas. “It is useless to take reactive actions decades later.”

“Neuroprotection measures ought to start very early, including the prenatal period and childhood. Defining paediatric environmental, nutritional, metabolic and genetic risk-factor interactions are key to preventing Alzheimer’s disease.”

The results can be found published online in the journal of Environmental Research. – AFP Relaxnews

New European research has found that exposure to air pollution while pregnant could change the structure of the brain in children,  affecting cognitive function .

Carried out by researchers from the Barcelona Institute for Global Health (ISGlobal) in Spain and Erasmus University Medical Center in the Netherlands, the research looked at a cohort of pregnant women in the Netherlands and followed the 783 children from foetal life until school age.

The team measured air pollution levels at home during the foetal life of the children and collected data on levels of exposure to nitrogen dioxide – an air pollutant caused by traffic and cigarette smoking – and coarse particles and fine particles of pollution.

When the children were between six and 10 years old, the researchers performed brain imaging tests to look at the structure of the brain.

The results showed that exposure to fine particles during foetal life was associated with a thinner outer layer of the brain, called the cortex, in several regions.

The researchers explained that this structural change could contribute to impaired inhibitory control, which is the ability to regulate self-control over temptations and impulsive behaviour and is related to mental health problems such as addictive behaviour and attention-deficit/hyperactivity disorder.

Worryingly, the team also found that the relationship between these brain structure alterations and fine particle exposure occurred when the average residential levels of fine particles in the study were well below the current acceptable limit set by the EU, with only 0.5% of the pregnant women in the study exposed to levels considered unsafe.

As the foetal brain hasn’t yet developed the mechanisms needed to protect against or remove environmental toxins, it is particularly vulnerable during pregnancy, with the study suggesting that exposure to levels even well below those considered safe could still cause permanent brain damage.

“This finding adds to previous studies that have linked acceptable air pollution levels with other complications including cognitive decline and foetal growth development. “Therefore, we cannot warrant the safety of the current levels of air pollution in our cities,” said lead author Dr Mònica Guxens, of Barcelona Institute for Global Health (ISGlobal).

Dr John Krystal, editor of Biological Psychiatry, the journal in which the study is published, also commented that, “Air pollution is so obviously bad for lungs, heart, and other organs that most of us have never considered its effects on the developing brain. But perhaps we should have learned from studies of maternal smoking that inhaling toxins may have lasting effects on cognitive development.” – AFP Relaxnews

EXPOSURE to high levels of certain air pollutants during pregnancy could increase the risk of abnormal foetal growth, according to a new study from Yale School of Public Health (YSPH). Researchers say the study is the first of its kind to be carried out in areas with very high air pollution levels.

Many recent studies have already suggested that air pollution poses a serious threat to health, finding associations between exposure to pollutants and an increased risk of conditions such as heart disease, asthma and male infertility.

However, according to the team behind the new study, there is a lack of research looking into the effect of pollution on foetal growth.

To test their hypothesis that high levels of PM10 during pregnancy increases the risk of abnormal foetal growth, the researchers analysed data from more than 8,000 women in Lanzhou, China between 2010 to 2012.

Particulate matter (PM) are particles found in the air that includes dust, dirt, smoke and liquid droplets. PM10 particles are less than 10 microns or 10 millionths of a meter across, which is several times thinner than a human hair.

In collaboration with researchers from the Gansu Provincial Maternity and Child Care Hospital, the team collected the daily average concentration for PM10 from the government monitoring stations in Lanzhou, and used ultrasound to measure four foetal growth parameters during pregnancy.

The results consistently showed a positive association between higher levels of exposure to pollutants and a higher risk of foetal head circumference overgrowth.

Dr Yawei Zhang, associate professor at YSPH, commented on the findings saying that the results now need to be confirmed by other studies which look at different populations.

He also added that it is important to identify the specific pollutants that are responsible for increased risk of foetal overgrowth by investigating the different components of PM10.

“Our results have important public health implications and call for future studies to explore the underlying mechanisms and postnatal consequences to the findings,” says Zhang. “We are going to replicate the findings in another birth cohort and will continue to identify individuals who are more susceptible to air pollution.”

Zhang also added that women in the Lanzhou region may lower the risk of foetal overgrowth by choosing their inception time and reducing their outdoor activities during the days with high air pollution. – AFP Relaxnews