changes in the heart like enlargement can occur on exposure to nitrogen
dioxide (NO2) and PM2.5 (small particles of air pollution)
changes were equal to the alterations seen in a heart that is just
beginning to have symptoms of failure; also, the changes got more significant
at higher exposure levels
- Setting air pollution
levels according to the guidelines of the World Health Organization (WHO)
would be better to curb the toxic effects
of United Kingdom (UK) can undergo changes in the heart structure, similar to
what is seen in the early stages of heart failure
even when exposed to low levels of air pollution that are well within the UK
However, the measured air pollution levels are fast approaching the limits placed
by the World Health Organization
(WHO). Numbers of WHO are much less than those set by the UK.
‘Exposure to even low levels of air pollution can cause heart remodeling. While the numbers of the toxicity measured were well within those set by the United Kingdom where the study was conducted, they are approaching the standards set by the World Health Organization, indicating that it is time to change those limits.’
research was conducted by a
team of scientists, led from Queen Mary University of London by Professor
Steffen Petersen, and was part-funded by the British Heart Foundation (BHF). It is
published in the journal Circulation
In England, air
pollution is currently the largest environmental risk factor linked to deaths
Globally, air pollution is a contributor to coronary heart disease
and stroke and accounts for
approximately six in ten (58%) deaths. This
research could give an insight as to how and why air pollution affects the heart
The team studied data from around 4,000 participants
in the UK Biobank study.
They gathered a range of personal information
(lifestyles, health record and where they have lived) from the volunteers.
This helped the team eliminate patients with
underlying heart problems and those who had relocated house during the study.
Other tests done were blood tests and health scans
like the heart MRI (magnetic resonance imaging) to measure the size, weight,
and function of the participants' hearts at fixed times.
Did Air pollution affect the Heart Structure?
was a clear association between exposures to nitrogen dioxide (NO2)
or PM2.5 (small particles of air pollution)
and the development
of larger right and left chambers in the heart.
The degree of enlargement was similar to that seen
in the early stages of heart failure.
The surprising things to note are that all the
participants were healthy and had no prior symptoms; they all lived outside UK
cities, and the association was seen only in the people living near the loud,
busy roads in those suburbs.
Did an Increase in Air Pollution Worsen the
exposures to the pollutants caused more significant changes in the structure of
An increase by 1 extra microgram (μg) per cubic
meter of PM2.5 and 10 extra μg per cubic meter of NO2 enlarged the heart by
annual exposures to PM2.5 were 8-12μg per cubic meter in the study.
Although this was well within the UK guidelines that have an exposure
limit of 25μg per cubic meter, the study results are fast approaching or past
WHO guidelines which are at 10μg per cubic meter, a much lower number than the
UK limit. In fact, the WHO has said that there are no safe limits of PM2.5.
A similar situation was seen with NO2 that was recorded at 10-50μg
per cubic meter
. This number was also approaching and above the WHO and UK
annual average guidelines that are both at 40μg per cubic meter.
Significance of the study
The British Heart Foundation conducted the research
ahead of the UK Government's consultation on their draft Clean Air Strategy
closing on 14 August 2018 to make sure that the public's heart and circulatory
health is at the center of discussions.
The Strategy would like to execute its mission of
halving the number of people in the UK living in areas where PM2.5 levels
exceed WHO guidelines by 2025, but the ultimate goal of the Strategy is to
reduce the health impacts of toxic air as quickly as possible.
Dr. Nay Aung who led the data analysis from Queen
Mary University of London said: "Although our study was observational and
hasn't yet shown a causal link, we saw significant changes in the heart, even
at relatively low levels of air pollution exposure. Our future studies will
include data from those living in inner cities like Central Manchester and
London, using more in-depth measurements of heart function, and we would expect
the findings to be even more pronounced and clinically important. "
Air pollution should be seen as a modifiable risk
factor similar to blood pressure, cholesterol and weight by doctors and the
general public when it comes to heart health.
The change should come from governments and public
bodies who must act immediately to make all areas safe and protect the
population from these harms.
Professor Jeremy Pearson,
Associate Medical Director at the BHF said: "What
is particularly worrying is that the levels of air pollution, particularly
PM2.5, at which this study saw people with heart remodeling are not even deemed
particularly high by the UK Government - this is why we are calling for the WHO
guidelines to be adopted. They are less than half of UK legal limits and while
we know there are no safe limits for some forms of air pollution, we believe
this is a crucial step in protecting the nation's heart health."
This step will also
improve the lives of those currently living with heart and circulatory
diseases that are proven to get affected by air pollution
- Air pollution linked to heart remodelling - (https://www.bhf.org.uk/what-we-do/news-from-the-bhf/news-archive/2018/august/air-pollution-linked-to-heart-remodelling)