People living near noisy roads could have an increased risk of high blood pressure, a new study suggests.
Long-term exposure to air pollution can also increase the 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 per cent 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 per cent 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.
"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."
