British Medical Journal research published this week links air pollution exposure to increased risk of strokes and anxiety
Air pollution is both linked to a higher risk of suffering a stroke and also associated with anxiety, according to two studies published in the British Medical Journal this week (March 25).
Strokes kill around five million people each year worldwide, with common risk factors including obesity, smoking and high blood pressure, but evidence of the impact of air pollution has been â€œlackingâ€, the BMJ said.
However, University of Edinburgh research funded by the charity British Heart Foundation (BHF) and published in the BMJ on Wednesday (March 25) looked at the association between short term air pollution exposure and stroke-related hospital admissions and deaths, analysing six millions strokes in 28 countries around the world.
The analysis found an association between strokes and carbon monoxide, sulphur dioxide, nitrogen dioxide and particulate matter PM10 and PM2.5, while the weakest association was with ozone.
The first day of exposure was found to have the strongest association, while those in low to middle income countries experiences the strongest association with strokes where there are also higher concentrations of gaseous pollutants.
According to the study authors, the results â€œsuggest a need for policy changes to reduce exposure in such highly polluted regionsâ€.
Chief executive of the BHF, Simon Gillespie, said:Â â€œThis new research only compounds what we already know, that air pollution is a blight on public health. We urge the UK government, ahead of the Supreme Court ruling next month, to do all that is possible, as quickly as possible, to protect us all from unnecessary risk of death or serious illness from air pollution. Every dayâ€™s delay puts thousands more people at risk.â€
BHF recently put out a policy statement on air pollution, calling on the government for improved warning systems for the public about pollution episodes and for MOT testing of vehicles to include physical checks of existing diesel particulate filters (DPFs).
The charity said it has provided Â£3.2 million for medical research on air pollution and cardiovascular events, largely regarding PM2.5, although it added that additional research is â€œurgently neededâ€ to investigate the likes of ozone and nitrogen dioxide.
Meanwhile, a second BMJ study published on Wednesday by researchers at the John Hopkins and Harvard universities in the USA found a â€œsignificantâ€ association between particulate matter PM2.5 and a higher risk of anxiety, based on a study of 71,271 women aged between 57 and 85 years.
The BMJ said anxiety is the most common psychiatric disorder and globally affects around 16% of people at some point in life, adding that it is associated with lessened productivity, increased medical care and risk of suicide.
No link was found with particles sized 2.5 to 10 in diameter, but women living closer to major roads were more likely to show anxiety symptoms than those living more than 200 metres away. But those living within 50 metres of a major road did not experience this association.
However, BMJ said that both of the studies were â€œobservational and no definitive conclusions can be drawn about cause and effect, and the teams of researchers call for more researchâ€.
Green Party MEP for South East England, Keith Taylor, called for more ultra low emission zones and said: â€œThe latest evidence, which shows the extreme danger of smog episodes, will be of great concern to people at risk of stroke.
â€œEven after UK and EU senior courts have found the governmentÂ failing to meet standards for safe air, ministers continue to ignore their responsibilities. There are solutions but there isn’t yet the political will at Westminster to make progress. The government must respond swiftly to this new evidence by both improving the communication system for smog episodes and taking action to cut harmful emissions in our city centres.â€
Charity Sustrans said that clean air is a â€œfundamental rightâ€ adding that the research showed that although â€œmany interventionsâ€ were needed to boost air quality, more needed to be done to down on the 55% of short journeys by car and encourage more to walk and cycle on these trips.
Claire Francis, head of policy for Sustrans, said: â€œTodayâ€™s health warning on poor air quality is another red light for traditional car-dominated transport policies. The government needs to do much more, right now, by committing to ambitious targets to get more people walking and cycling and the long term investment to make walking and cycling a safe option for everyone.â€
The stroke research follows another study this week in Germany by the Institute for Diabetes Research at the Helmholtz Centre, which linked high levels of particle dust pollution with type 1 diabetes in children.
Data was analysed from 671 children with type 1 diabetes who were diagnosed between April 2009 and May 2013, which found that those exposed to high levels of air pollution in residential environments developed the condition three years earlier on average than those in low pollution areas.