Long-term exposure to pollution of the ambient air increases gradually the risk of hypertension, according to a study conducted with more than 41,000 people, released Tuesday.
Noise pollution — caused by traffic, particularly — also increases the likelihood of developing hypertension, according to the authors of this work.
According to the European study, more than one person out of 100 people of the same age would develop high blood pressure in the most polluted part of a city against a more breathable neighborhood.
This risk is similar to that of an overweight person (BMI: body mass index between 25 and 30).
The study, published in the European Heart Journal, looked at 41,072 people in Norway, Sweden, Denmark, Germany and Spain.
Hypertension is a major risk factor for diseases (stroke …) and premature death.
None of the participants had hypertension at the start, but in the study, 6,207 of them (15%) reported having developed hypertension or taking drugs against hypertension.
Between 2008 and 2011, the researchers measured the air pollution during three separate periods of two weeks to account for seasonal effects.
They analyzed the concentrations of suspended particles in the air of different sizes, including those (PM 2.5) that penetrate deep into the lungs.
Each additional five micro-grams — or millionths of a gram — of the smaller studied particles (PM 2.5) upped the risk of hypertension by a fifth for the inhabitants of the most polluted areas, compared to those living in the least polluted places.
For noise pollution, according to the researchers, people living in noisy streets with noisy night traffic on average had an increased risk of six percent of developing hypertension compared to those living in streets where the noise levels were lower by at least 20%.
According to the study, the average levels of pollution were higher in Germany and Spain than in the Nordic countries. The highest levels of noise exposure were observed in Sweden and Spain.
However, the effect of noise pollution eside, the impact of air pollution on blood pressure persists, according to the head of the study Barbara Hoffmann (University of Düsseldorf, Germany).
These results show that long-term exposure to air pollution particles is associated with a higher incidence of self-reported hypertension. Like almost everyone is exposed to air pollution during its life, this leads to a high number of cases of hypertension.
The current legislation does not protect the European adequately against the harmful effects of air pollution, the researchers conclude.