Noise pollution in urban areas has significant, negative impacts on heart health according to studies published on Tuesday.

The studies conducted in France and Germany, respectively, show that people already suffering from heart as well as cardiovascular problems are among the vulnerable groups and will be subjected to debilitating effects on their health owing to this menace.

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In Germany’s Bremen, 430 consecutive patients with acute myocardial infarctions (MI) who were admitted to a nearby heart centre and were 50 years of age or younger were enrolled in the trial. The researchers found that residential noise exposure levels were higher than those of the general population in the same region when they calculated levels of noise exposure. Individuals who had MI and a low Cardiovascular Disease (CVD) score (greater or smaller than 2.5 per cent) suggests they had less traditional risk factors like diabetes or smoking, showed considerably higher noise exposure than patients with a high CVD score.

This is important because cardiovascular risk in young people who are otherwise deemed low risk may be underestimated by traditional risk assessment techniques.

An independent French study evaluated the effect of noise exposure on the prognosis following a first MI, “we found a strong association between urban noise exposure, particularly at night, and worse prognosis at 1 year after a first MI” in the ENVI-MI research”, said investigator Professor Marianne Zeller of the University of Burgundy and Hospital of Dijon.

Data for 864 patients who were hospitalised for an acute MI and survived for at least 28 days following the MI were gathered from the French Observatory Database (RICO).

A major adverse cardiovascular event (MACE; cardiac mortality, rehospitalisation for heart failure, recurrent MI, emergency revascularisation, stroke, angina and/or unstable angina) was reported by 19 per cent of the participants at the 1-year follow-up.

The average noise level in A-weighted decibels [dB(A)] for each patient’s home address was measured every day. It was found to be 56.0 during the day and 49.0 at night. These levels of noise exposure were deemed to be moderate and typical for a significant portion of the European population. Notably, regardless of air pollution or socioeconomic status, there was a 25 per cent greater risk of MACE for every 10 dB(A) increase in noise during the night (hazard ratio 1.25; 95 per cent, confidence interval 1.09–1.43).

“These data provide some of the first insights that noise exposure can affect prognosis. If confirmed by larger prospective studies, our analysis could help to identify new opportunities for environment-based secondary-prevention strategies, including noise barriers for high-risk MI patients,” Prof Zeller said.