Air pollution and traffic noise come with a lot of problems, such as breathing troubles, headaches and general feelings of frustration, but now long-term city dwellers can add high blood pressure to that list.

A study published in the European Heart Journal found those conditions of city life had a similar effect on blood pressure as a person being overweight — an extra 1 percent of adults in the same age group who lived in their cities’ most polluted areas developed high blood pressure, also known as hypertension, unlike their counterparts in less polluted areas.

The researchers followed more than 41,000 people in Norway, Sweden, Denmark, Germany and Spain for between five and nine years and while nighttime traffic noise was “weakly positively associated with the incidence of self-reported hypertension,” the study still connected the two just as it connected air pollution and high blood pressure. None of the participants had high blood pressure at the beginning, but about 15 percent reported developing the condition or taking medication for it by the end of the study period.

Specifically, for every five micrograms per cubic meter of fine particulate matter — with a diameter of less than 2.5 micrometers — the risk of developing high blood pressure increased by one-fifth. Having more soot in the air also increased the risk.

The World Health Organization lists guideline values for the lowest risk to health possible, but those currently only go as low as 10 micrograms per cubic meter, as an annual average, for the size of particulate matter the new study measured. The organization also notes that the small particulate matter, which consists largely of things like sulfate, black carbon, mineral dust, ammonia and water, can “penetrate and lodge deep inside the lungs.”

“Chronic exposure to particles contributes to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer,” the WHO says. “There is a close, quantitative relationship between exposure to high concentrations of small particulates ... and increased mortality or morbidity, both daily and over time.”

The results published in the European Heart Journal are significant because “high blood pressure is the most important risk factor for premature illness and death,” according to a statement from the European Society of Cardiology.

The researchers had measured air pollution at dozens of locations in each of the areas being studied and assessed traffic density levels outside the subjects’ homes, and investigated the links between those two living conditions and the medical condition separately. The society said it’s possible the biological explanation for the results is that pollution causes inflammation in parts of the cardiovascular system, imbalances the nervous system or allows damaged molecules to build up in the body. Noise is also believed to affect hormones.

“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,” lead researcher Barbara Hoffmann, a professor at the Centre for Health and Society at Heinrich-Heine-University of Düsseldorf, Germany, said in a statement. “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.” She added that regulations should be tightened to mitigate air pollution’s effect on public health.

The highest average levels of pollution in the study area were found in Germany and Spain, while the noisiest and most congested were in Sweden and Spain.

Source: Hoffman B, Fuks KB, Weinmayr G, 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. European Heart Journal. 2016.