Long-term exposure to airplane noise — particularly during the night — is associated with an increased risk of developing high blood pressure and perhaps heart arrhythmia (an irregular heartbeat) and stroke, according to a new European study.

The study also found that the effect of airplane noise on high blood pressure was independent of the noise’s “annoyance factor” — in other words, it was not related to how much people said the noise bothered them.

“Our latest study adds to a number of recent studies providing evidence that noise exposure from transport sources may be related to ill health,” wrote Klea Katsouyanni, the study’s senior author and an environmental epidemiologist at King’s College London, in an article she wrote about the study for The Conversation. “It provides additional justification for policy measures to reduce noise from aircraft during the night.”

A follow-up study

For their study, Katsouyanni and her colleagues followed up on a group of people who had participated in an earlier study, called Hypertension and Exposure to Noise Near Airports (HYENA), which had found a higher risk of high blood pressure among people living near six European airports in 2004-2006.

Because of its design, however, HYENA was able to provide only a “snapshot” of the effect of noise exposure on high blood pressure and could not ensure that the noise exposure had preceded the occurrence of high blood pressure, says Katsouyanni.

To address that problem, she and her colleagues set out in 2013 to gather updated health information on the 780 HYENA participants who had lived near Athens International Airport.

“That way we could be certain that exposure to noise preceded the appearance of hypertension or other cardiovascular problems, at least among those not having this problem at the time of the original study,” she explains.

(FYI: Athens International Airport handles about 600 aircraft takeoffs and landings per day, according to the study. That compares to about 1,000 per day for the Minneapolis-St. Paul International Airport.)

Many of the original Greek participants in the HYENA study had died or moved away, and others did not want to take part in the follow-up study. But 420 of the participants did agree to go through another round of questions with the researchers about their health and their experiences with — and attitudes toward — noise.

Of those 420 participants, just under half (45 percent) were exposed to more than 55 decibels of daytime airplane noise, while about a quarter (27 percent) were exposed to more than 45 decibels of night-time airplane noise.  (For comparison, 70 decibels is the noise level of an average vacuum cleaner or hair dryer.)

Roads, however, were not a major source of noise for the participants. Fewer than 11 percent were exposed to road noise of more than 55 decibels.

Key findings

Katsouyanni and her colleagues found 71 new cases of high blood pressure among the participants. High blood pressure was determined by a blood pressure reading or by a confirmed diagnosis by the participant’s physician.

The researchers then looked to see if high blood pressure was associated with higher noise levels.

“Every 10 decibel increase of aircraft noise at night was associated with a 2.6 times greater risk of developing hypertension,” says Katsouyanni. “For example, someone who lived in a home with 50 decibels of noise at night had a 2.6 times greater risk of developing hypertension than someone who lived in a home with 40 decibels of noise at night.”

That finding held even after adjusting for factors that are known to have an effect on blood pressure, such as age, gender, body mass index, smoking and exercise.

The researchers also found evidence that the risk of physician-diagnosed heart arrhythmia and stroke increased as airplane noise went up, but those connections were, statistically, much weaker.

They did not find any association between airplane noise and an increased risk of having a heart attack or of developing type 2 diabetes. Nor did they find a strong link between road noise and ill health — perhaps because so few people experienced road noise.

Limitations and implications

Although the design of this study was an improvement on the original HYENA research, it still has several important limitations. The number of people involved was relatively small, and the researchers were unable to look at the medical records of the 78 people who died between the earlier study and this one to see what caused their deaths.

Most important, these findings are — like the ones of the earlier study — observational, which means they can’t prove that the airplane noise is behind the increased risk of high blood pressure among the participants.

Still, the study seems to support other evidence that noise is an often-underappreciated health problem.

“There is growing evidence that high levels of noise are bad for our health,” writes Katsouranni. “Being exposed to high levels of occupational and social noise can lead to hearing loss. Exposure to noise has also been associated with annoyance and sleep disturbance. There is also evidence that exposure to noise from aircraft and from road traffic may affect children’s school performance.”

And, apparently, we may not even have to be consciously bothered by the noise for it to affect our health.

FMI: The study was published in the journal Occupational & Environmental Medicine where it is, unfortunately, behind a paywall.