Pollution, previously linked to poor respiratory health, has now been linked to raised blood pressure.
German researchers looked at 5,000 people and found long-term exposure increased blood pressure, even when other key factors were considered.
The team, which has presented its work to the American Thoracic Society, says efforts should be made to reduce exposure to pollution.
Although the increase may not mean much for healthy people, “this small increase may actually be able to a trigger a heart attack or stroke,” study author Dr. Robert D. Brook, an assistant professor of medicine at the University of Michigan, said in a university news release.
An estimated nearly one in three Americans suffer from high blood pressure, meaning the heart is straining to push blood through the circulatory system.
In the study, which appears in a recent issue of Hypertension, researchers tested 83 people as they breathed levels of air pollution similar to those in an urban city near a roadway.
“We looked at their blood vessels and then their responses before and after breathing high levels of air pollution,” study co-author Robert Bard, a University of Michigan clinic research coordinator, said in a news release.
People from traditionally urban areas could be genetically better suited to fighting infection, say researchers.
The University of London team looked at how many people carried a specific gene variant known to give them resistance to TB and leprosy.
It was more common in those from areas with a longer history of urbanisation, where the diseases were more likely to have been rife at one point.
They described the discovery as an example of “evolution in action”.
The phenomenon, reported in the journal Evolution, is suggested as an example of so-called “selective pressure” in relation to disease resistance.
It happens because, when a population is exposed to a killer illness, the people who are best placed to pass on their genes to the next generation are those whose genetic make-up helps them fight the infection.
In towns and cities, where people intermingle far more closely, the likelihood of being exposed to infectious disease is theoretically higher.
So, over the centuries, the greater the level of historical exposure, the more likely it is that these resistance genes will be spread widely among the population.
http://www.bbc.co.uk/news/health-11408114
AVOIDING sugary drinks may help to lower blood pressure, scientists have claimed.
A US study published in the Journal of the American Heart Association says cutting consumption of fizzy pop by two glasses a day could reduce the risk of dying of a stroke by eight per cent and coronary heart disease by five per cent.
Sugar-laced drinks have long been linked to a greater risk of obesity and diabetes but their effect on blood pressure had been uncertain.
Louisiana State University’s Dr Liwei Chen, who led the research, said: “Our findings suggest reducing sugar-sweetened beverages and sugar consumption may be an important dietary strategy to lower blood pressure and further reduce other blood pressure-related diseases.”
Blood pressure is measured in millimetres of mercury (mmHg) and written as two numbers. A normal healthy blood pressure would be at or below 120 over 80 (120/80).