The risks of stroke, heart and circulatory disease
are higher in areas with a lot of aircraft noise,
researchers say.
Their study of 3.6 million residents near Heathrow
Airport suggested the risks were 10-20% higher in
areas with the highest levels of aircraft noise.
The team's findings are published in the British
Medical Journal.
They agreed with other experts that noise was not
necessarily to blame and more work was needed.
Their work suggests a higher risk for both hospital
admissions and deaths from stroke, heart and
circulatory disease for the 2% of the study - about
70,000 people - who lived where the aircraft noise was
loudest.
The lead author, Dr Anna Hansell, from Imperial College
London, said: "The exact role that noise exposure may
play in ill health is not well established.
"However, it is plausible that it might be contributing -
for example, by raising blood pressure or by disturbing
people's sleep."
"There's a 'startle reaction' to loud noise - if you're
suddenly exposed to it, the heart rate and blood
pressure increase.
"And aircraft noise can be annoying for some people,
which can also affect their blood pressure, leading to
illness.
"The relative importance of daytime and night-time
noise from aircraft also needs to be investigated
further."
The study used data about noise levels in 2001 from
the Civil Aviation Authority, covering 12 London
boroughs and nine districts outside of London where
aircraft noise exceeds 50 decibels - about the volume
of a normal conversation in a quiet room.
The authors say fewer people are now affected by the
highest levels of noise (above 63 decibels) - despite
more planes being in the skies - because of changes in
aircraft design and flight plans.
The researchers - from Imperial and also King's College
London - adjusted their work in an effort to eliminate
other factors that might have a relationship with stroke
and heart disease, such as deprivation, South Asian
ethnicity and smoking-related illness.
They stressed that the higher risk of illness related to
aircraft noise remained much less significant than the
risks from lifestyle factors - including smoking, a lack of
exercise or poor diet.
In an accompanying editorial, Prof Stephen
Stansfeld, from Queen Mary University of London, said:
"These results imply that the siting of airports and
consequent exposure to aircraft noise may have direct
effects on the health of the surrounding population.
"Planners need to take this into account when
expanding airports in heavily populated areas or
planning new airports."
Noise 'has fallen'
The study covered 12 London boroughs in the centre
and west of the capital - and nine council districts
beyond London, including Windsor and Maidenhead,
Slough and Wokingham.
Heathrow Airport's director of sustainability, Matt
Gorman, said: "We are already taking significant steps
to tackle the issue of noise.
"We are charging airlines more for noisier aircraft,
offering insulation and double glazing to local residents
and are working with noise campaigners to give people
predictable periods of respite from noise.
"Together these measures have meant that the number
of people affected by noise has fallen by 90% since the
1970s, despite the number of flights almost doubling."
A government spokesman said: "The number of people
affected by high levels of noise around Heathrow has
been falling for years due to improvements in aviation
technology, better planning of flight paths and other
factors. We would expect to see this trend continue."
A separate study , also published on Wednesday in the
BMJ, demonstrates a higher rate of admission to
hospital with cardiovascular problems for people living
near 89 airports in the US.
Prof Kevin McConway, from the Open University, said:
"Both of these studies are thorough and well-
conducted. But, even taken together, they don't prove
that aircraft noise actually causes heart disease and
strokes.
"A major difficulty in interpreting what these studies
tell us is that they are based on data for geographical
areas, not for individual people."
Over the coming months, Public Health England will
recruit experts to further examine the public health
issues around exposure to noise.
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