High air pollution levels could be a contributory factor in the onset of dementia, a new study from Kings College London suggested this week.
Data collected in the capital appeared to show that people aged over 50 living in areas with high nitrogen dioxide levels (NOx) had a 40 per cent higher risk of developing dementia than those in lower NOx areas.
The findings were published in the BMJ Open Journal this week and although they do not establish a firm link between air pollution and dementia, the authors say it cannot be explained by other contributory factors.
However, scientists say the results of Kings’ observational study should be treated with some caution as it could not accurately record other possible causes such as lifestyle factors, economic deprivation, or the amount of air pollution each patient was exposed to.
The research took air and noise pollution levels across London postcodes and compared these with health records of more than 130,000 patients aged between 50-79 at 75 GP practices.
Their health was monitored between 2005 and 2012 and 1.7 per cent of them were diagnosed with dementia during this time.
Air pollution has already been identified as a factor in cardiovascular and respiratory diseases, but this study suggests that its effects could be more widespread, backing up previous research in this area.
Other studies have identified air pollution as a risk to children and expectant mothers and, according to recent Chinese research, breathing dirty air could also cause reduced intelligence.
The authors of the Kings College report also warned that the connection between air pollution and dementia could begin in children, impairing cognitive development and causing changes in the brain’s immune responses.
Simon Alcock, from environmental law firm ClientEarth, which has taken the Government to court on a number of occasions over poor air quality, said there was an urgent need for new legislation and clean air zones in heavily polluted areas.
A spokesperson for Defra said air pollution levels were falling and that the Government was committed to taking further action, which included ending the sale of diesel and petrol cars and vans by 2040.