People exposed to air pollution and traffic noise long term have an increased risk of developing high blood pressure, according to a major European study published today.
In the largest study to date on the effects of both air pollution and traffic, researchers found that up to one extra person per 100 people living in cities’ most polluted areas would develop high blood pressure compared to those living in the less polluted areas.
The findings are reported in the European Heart Journal.
A total of 41,072 people living in Norway, Sweden, Denmark, Germany and Spain took part in the study – part of the “European Study of Cohorts for Air Pollution Effects” (ESCAPE) project, which is investigating long-term effects of exposure to air pollution on human health in Europe.
The study enabled the researchers to estimate the risk that was linked to air pollution and the risk linked to noise separately and they found that the link to air pollution with hypertension remained even when exposure to traffic noise was considered in the analysis.
This is important, they write, because there are different ways in which air pollution and noise can be reduced.
The research team measured air pollution during three separate two-week periods between 2008 and 2011, using filters to capture information on concentrations of PM10, PM2.5, PM coarse, and PM2.5 absorbance.
These measurements were taken at 20 sites in each of the study areas, and measurements of nitrogen oxides were measured at 40 different sites in each area. Traffic density was assessed outside the homes of the participants and traffic noise was modelled according to the EU Directive on environmental noise.
They discovered that for every five micrograms per cubic metre (5 µg/m3) of PM2.5, the risk of hypertension increased by 22% in people living in the most polluted areas compared to those in the least polluted areas. Higher soot concentrations also increased the risk.
The team also 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.
None of the participants had hypertension when they joined the study, but during the follow-up period 6,207 people (15%) reported that they developed hypertension or started to take blood pressure-lowering medications.
Professor Barbara Hoffmann, Professor of Environmental Epidemiology at the Centre for Health and Society at Heinrich-Heine-University of Düsseldorf, Germany, who led the analysis, said: “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.”
Professor Jeremy Pearson, associate medical director at the British Heart Foundation, warned: "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."
Fuks K, Weinmayr G, Basagña X et al. Long-term exposure to ambient air pollution and traffic noise and incident hypertension in seven cohorts of the European study of cohorts for air pollution effects (ESCAPE). European Heart Journal 25 October 2016; doi:10.1093/eurheartj/ehw413 [abstract]
Leave a Reply