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Air pollution can damage your BRAIN: Exposure to smog in childhood can affect your cognitive skills up to 60 years later, study warns

 Being exposed to smog and air pollution while a child can damage your cognitive skills up to six decades after you were exposed, a new study has warned.

University of Edinburgh experts tested the general intelligence of over 500 people aged 70 using a test the same group completed when they were 11 years old.

They also examined where the group had lived throughout their life to estimate the levels of air pollution they were exposed to during their early childhood.  


Those volunteers who had been exposed to air pollution as a child had suffered a small - but detectable - level of cognitive decline between the age of 11 and 70. 

Researchers behind this study didn't examine why air pollution appears to cause reduced cognitive skill, but previous studies have found it may be due to metal-toting particles in the pollution reaching the brain and damaging neurons. 

Dr Susan Kohlhaas from Alzhaeimer's UK, who was not involved in the study, said society should work towards cleaner city air as a 'critical public health goal. 

Being exposed to smog and air pollution while a child can damage your cognitive skills up to six decades after you were exposed, a new study has warned. Stock image

Being exposed to smog and air pollution while a child can damage your cognitive skills up to six decades after you were exposed, a new study has warned. Stock image

The study was designed to show it is possible to estimate historical air pollution - and then explore who this related to cognitive ability throughout life, the team say. 

The Scottish researchers used statistical models to analyse the relationship between someone's exposure to air pollution and their thinking skills as they get older.  

They also considered lifestyle factors, such as socio-economic status and smoking.

Kohlhaas said there was a growing body of evidence that air pollution can increase the risk of developing dementia - alongside a range of other external factors.

'Dementia isn’t an inevitable part of getting older, and factors including age, genetics and the environment affect the risk of developing the condition,' she said.


Dr Tom Russ, Director of the Alzheimer Scotland Dementia Research Centre at the University of Edinburgh, said the study shows the danger of air pollution. 

'For the first time we have shown the effect that exposure to air pollution very early in life could have on the brain many decades later,' he explained. 

'This is the first step towards understanding the harmful effects of air pollution on the brain and could help reduce the risk of dementia for future generations.'

Researchers say until now it has not been possible to explore the impact of early exposure to air pollution on thinking skills in later life because of a lack of data on air pollution levels before the 1990s when routine monitoring began.

The team discovered that exposure to air pollution in childhood had a small - but detectable - association with lower cognitive abilities between the ages of 11 and 70 years. Stock image

The team discovered that exposure to air pollution in childhood had a small - but detectable - association with lower cognitive abilities between the ages of 11 and 70 years. Stock image

For this study researchers used a model called the EMEP4UK atmospheric chemistry transport model to determine pollution levels.

These are known as historical fine particulate matter (PM2.5) concentrations - for the years 1935, 1950, 1970, 1980, and 1990. 

They combined these historical findings with contemporary modelled data from 2001 to estimate life course exposure in the 70-year-old volunteers.


They were part of the Lothian Birth Cohort 1936 study, a group of individuals who were born in 1936 and took part in the Scottish Mental Survey of 1947.

Since 1999, researchers have been working with the Lothian Birth Cohorts to chart how a person's thinking power changes over their lifetime.

The team say this was the first study to examine cognitive decline and how it is linked to air pollution by using a long-term cohort study.

They say future work should be done to look at the link between air pollution and cognitive decline throughout the average lifespan of a human group.

'The modelled historical air pollution data need to be refined and harmonised across different time points, and these data used to provide a robust estimate of life course exposure,' the authors wrote in their paper.

'But we believe that we have demonstrated the feasibility and value of this approach,' they added.

Dr Kohlhaas said that while the study didn't go into the effects of air pollution on developing dementia, it did look at the link between pollution and thinking. 

'From this one study alone, we cannot link exposure to air pollution in childhood to any meaningful change between the ages of 11 and 70 years,' she said. 

'However, this research does demonstrate that using historical data to study large scale affects like this in relation to brain health is feasible.'

'We must do all we can to help reduce the number of people who will go on to develop memory and thinking problems in future and that’s why Alzheimer’s Research UK has launched the Think Brain Health campaign as a first step.'

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