Study links blood pressure risk to traffic noise

People living near noisy roads could have a bigger risk of high blood pressure, a new study suggests.

Meanwhile, long-term exposure to air pollution can also increase a person's risk, experts found.

The new study tracked 41,000 people in five different countries for up to nine years.

An extra adult per every 100 living in the most polluted areas will develop high blood pressure compared with those living in the less polluted areas, the research suggests.

The study, published in the European Heart Journal, also found that traffic noise is associated with an increase in cases of hypertension.

Researchers gathered information on 41,000 people from Norway, Sweden, Denmark, Germany and Spain at the start of the study and again during a follow-up examination between five and nine years later.

None suffered high blood pressure when they joined the study, but during the follow-up period 15% had developed hypertension or started to take blood pressure-lowering medications.

The researchers also measured air pollution during three separate two-week periods.

And they assessed traffic density outside the homes of participants.

They found that people living in noisy streets, where there were average night-time noise levels of 50 decibels, had a 6% increased risk of developing hypertension compared to those living on quieter streets.

And those living in areas with higher concentrations of polluting particles were significantly more likely to have self-reported high blood pressure.

Lead author Barbara Hoffmann, professor of environmental epidemiology at at Heinrich-Heine-University of Dusseldorf, Germany, said: "Our findings show that long-term exposure to particulate air pollution is associated with a higher incidence of self-reported hypertension and with intake of anti-hypertensive medication.

"As virtually everybody is exposed to air pollution for all of their lives, this leads to a high number of hypertension cases, posing a great burden on the individual and on society.

"Exposure to traffic noise shares many of the same sources with air pollution and so has the potential to confound the estimates of the adverse effects of pollution on human health. However, this study controlled for traffic noise exposure and found that the associations of air pollution with hypertension did not vanish. This is important because preventive measures for air pollution and noise differ.

"One very important aspect is that these associations can be seen in people living well below current European air pollution standards. This means the current legislation does not protect the European population adequately from adverse effects of air pollution.

"Given the ubiquitous presence of air pollution and the importance of hypertension as the most important risk factor for cardiovascular disease, these results have important public health consequences and call for more stringent air quality regulations."

Jenny Bates, Friends of the Earth air pollution campaigner, said: "The evidence continues to mount about the impact of air pollution on people's health and well-being.

"Crucially, this study shows that there are health risks, even when levels of fine particles of air pollution are below EU legal limits - and in fact the World Health Organisation say there is no known safe limit for this pollution.

"Air pollution leads to 40,000 early deaths in the UK every year. It causes lung cancer, contributes to respiratory disease including worsening of asthma, and to heart disease with this latest study linking it to high blood pressure.

"Urgent action is needed to get dirty diesel vehicles off our roads, and to reduce road traffic.

"The UK Government must be bold and put in place a plan to phase out diesel, support Clean Air Zones across the country and offer people real alternatives to driving, in order to save lives and improve health."

Jeremy Pearson, associate medical director at the British Heart Foundation, said: "High blood pressure is a silent killer. You may not notice you have it, but it can increase your risk of coronary heart disease and stroke which is why managing your blood pressure is so important.

"This large study shows that people who are exposed to higher levels of vehicle-derived pollution are slightly more likely to have high blood pressure, a known risk factor for heart disease.

"However, the authors only found a significant relationship between high blood pressure and air pollution when using self-reported data rather than measured blood pressure, which raises questions about the strength of their main conclusion. The authors themselves are cautious about the strength of their conclusion that effects of traffic noise on blood pressure can be separately detected.

"The study should therefore be seen as a further pointer to adverse effects of pollution on cardiovascular health, reinforcing current views that maximum exposure levels currently recommended by the EU are not low enough to minimise risk.

"Air pollution, particularly from small particles in diesel fumes, is known to increase a person's risk of heart attacks and strokes. Thanks to the support and generosity of the public the BHF is funding research which looks at how air pollution causes abnormalities in the blood vessels, however, further research is needed to understand exactly how air pollutants can increase blood pressure and how important their effects are on cardiovascular health."