People who live near airports are at increased risk of high blood pressure, our latest research shows. We found that exposure to high levels of noise, especially during the night, more than doubles the risk of being diagnosed with hypertension (high blood pressure). We also found some evidence that aircraft noise may lead to an increased risk of heart arrhythmia and stroke.
An earlier study, called HYENA, investigated the relationship between noise near airports and the risk of hypertension. The researchers, coordinated by Imperial College London, studied people living near six European airports in 2004-2006. Since noise exposure levels cannot be measured for every study participant, exposure to aircraft noise was modelled and linked to each participant’s home address using geographic information systems.
The researchers found that people who were exposed to higher levels of noise at night were more likely to have hypertension. But, in HYENA, noise exposure and hypertension were studied concurrently, providing a snapshot during the study period. However, with this type of study design (cross-sectional) it is not possible to tell if noise exposure preceded the occurrence of hypertension.
For our study, we attempted to contact the 780 HYENA participants who’d lived near Athens International Airport. The time that elapsed allowed us to study the effects of noise during the earlier period (in 2004-2006) on health in 2013. 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.
A number of the original participants had died, moved home or could not be found. But of the 537 people who still resided in the area, 420 agreed to take part in our follow-up study. Just under half of the participants (45%) were exposed to more than 55 decibels of daytime aircraft noise, while a quarter (27%) were exposed to more than 45 decibels of night-time aircraft noise. Fewer participants (11%) were exposed to significant road noise of more than 55 decibels, so road traffic noise in this area was relatively low.
Every 10 decibel increase of aircraft noise at night was associated with a 2.6 times greater risk of developing hypertension. 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.
There was some weaker evidence that the risk of cardiac arrhythmia and stroke was also increased as noise levels went up.
Annoyance from noise was only somewhat correlated with actual noise levels. Higher annoyance scores were associated with slightly increased risk of hypertension, but only during the day. It was found that the effect of aircraft noise exposure on hypertension was independent of annoyance to aircraft noise.
In our analysis, we controlled for age, sex, body mass index, smoking, exercise and other factors that can have an effect on blood pressure.
There is growing evidence that high levels of noise are bad for our health. 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. But can we be certain that exposure to aircraft noise during the night leads to increased blood pressure and worsens cardiovascular health?
This is one of the first follow-up studies to look at long-term effects of aircraft noise exposure. The number of people involved is relatively small and the results need to be confirmed by other studies. However, our latest study adds to a number of recent studies providing evidence that noise exposure from transport sources may be related to ill health. It provides additional justification for policy measures to reduce noise from aircraft during the night.
About The Author
Klea Katsouyanni, Professor of Environmental Epidemiology, King's College London