October 25, 2016

expert reaction to study looking at air pollution, traffic noise and blood pressure

Scientists publishing in European Heart Journal have investigated the effect of traffic-related air pollution and noise and report that they are associated with increased incidence of self-reported (but not measured) high blood pressure.

Prof. Nick Hewitt, Professor of Atmospheric Chemistry, Lancaster University, said:

“This study provides further evidence that European air quality standards are not stringent enough, nor sufficiently enforced. The current European limit value for fine particle (PM2.5) pollution is two and a half times higher than the World Health Organisation guideline value for the same pollutant, which is set on the basis of scientific evidence specifically to protect human 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.”

Prof. Francesco Cappuccio, Cephalon Professor of Cardiovascular Medicine & Epidemiology, University of Warwick, and Vice-President, British & Irish Hypertension Society, said:

“The present aggregate analysis suggests that whilst measures of air pollution across different European countries are associated with a greater risk of ‘self-reported’ hypertension, there is no evidence of such an association with the incidence of ‘measured’ hypertension.

“This finding, understated in both the study’s conclusion and in the press release, introduces a big note of caution. It is well recognised that the awareness of hypertension in the general population is weakly correlated with its presence when measured, and the lack of symptoms or signs often associated with it makes self-reported estimates unreliable, often biasing population hypertension estimates.

“In the future, similar population studies should only rely on objective, direct and valid measures of blood pressure in the community to estimate prevalence or incidence of hypertension.”

‘Long-termexposure to ambient air pollution and traffic noise and incident hypertension in seven cohorts of the European study of cohorts for air pollution effects (ESCAPE)’ by Kateryna B. Fuks et al. published in the European Heart Journal on Tuesday 25 October 2016. 

Declared interests

Prof. Nick Hewitt: “I have no conflicts of interest to declare.”

None others received.