People who are repeatedly exposed to high levels of noise — and are annoyed by it — may be at greater risk of developing atrial fibrillation, according to a study published recently in the International Journal of Cardiology.
The study found that this association was particularly true when people are exposed to airplane noise and when the noise occurs at night.
“The study shows for the first time that noise annoyance caused by various noise sources during the day and night is associated with an increased risk of atrial fibrillation,” said Omar Hahad, the lead author of the study and a research associate at Mainz University in Germany, in a released statement. “Overall, we were able to demonstrate a stronger influence of annoyance caused by nocturnal noise on the heart rhythm.”
A risk factor for stroke
Atrial fibrillation, the most common form of heart arrhythmia, is characterized by an irregular and abnormally fast heartbeat. It occurs when the two upper chambers of the heart (the atria) beat out-of-step with the two lower ones (the ventricles). Symptoms include heart palpitations, shortness of breath and weakness, although some episodes may not produce any symptoms.
Atrial fibrillation may occur occasionally or persistently. Usually, the condition isn’t life threatening, but it can increase the risk of stroke, heart failure and other heart-related complications. An estimated 2.7 to 6.1 million people in the United States have the condition, and it is associated with more than 750,000 hospitalizations and 130,000 deaths each year, according to the Centers for Disease Control and Prevention.
The risk of developing atrial fibrillation increases with age. About 9 percent of people over the age of 65 have the condition. Other risk factors include high blood pressure, obesity and diabetes.
Why and how the study was done
As background information in the study points out, previous research has linked anger and annoyance to an increased risk of cardiovascular diseases, especially high blood pressure and coronary heart disease. Research has also linked anger, disturbed sleep, exhaustion and stress resulting from repeated noise exposure to poorer health — especially poorer cardiovascular health.
“We have already been able to prove the connection between noise and vascular disease in several studies in healthy volunteers, patients with established coronary artery disease and also in preclinical studies,” said Dr. Thomas Münzel, the study’s senior author and a cardiologist at Mainz University, in the released statement. “[But] there has been no explicit study being published which addresses to what extent noise annoyance can cause cardiac arrhythmia.”
For their current study, the Mainz University researchers analyzed data collected from almost 15,000 German men and women, aged 35 to 74, participating in the ongoing Gutenberg Health Study.
Eighteen percent of the participants had been diagnosed with atrial fibrillation.
In addition to information on the participants’ health, the data included the participants’ answers to questions about their psychological health and about any sources of noise — during the day or at night — that caused them annoyance.
About 80 percent of the participants reported being regularly annoyed by noise, including 10.5 percent who said the annoyance was “extreme.”
The analysis of all that data revealed that compared to people who reported no noise-related annoyance, those who reported extreme annoyance were more likely to have a diagnosis of atrial fibrillation — 14.6 percent vs. 23.4 percent.
The study also found that depression among the participants increased steadily as the degree of noise-related annoyance climbed. About 6 percent of those who reported no annoyance reported symptoms of depression compared to almost 12 percent of those who reported extreme annoyance.
Aircraft was the noise source most often cited as being annoying in the study, followed by road noise and general neighborhood noise. Aircraft noise was also the leading source of extreme noise in the study.
People who reported being annoyed by any form of noise at night were more likely to have been diagnosed with atrial fibrillation, the study also found.
Limitations and implications
This study was an observational one, so it can’t prove a link between regular noise exposure and atrial fibrillation. Also, the study measured noise annoyance, not physical noise. Other factors, not addressed in the study, may therefore explain the results.
Still, the findings are intriguing — and worrisome, given the growing problem of noise pollution around the world.
“The relationship between noise annoyance and atrial fibrillation is an important finding that may also explain why noise can lead to more strokes,” said Munzel. “However, one must not forget that noise also leads to damage to health without the need for an anger reaction.”
FMI: The study can be read in full on the website of the International Journal of Cardiology.