Air Pollution and Carotid Artery Thickness: What’s the Connection?
There may be a link between air pollution and the thickness of the walls of the
main arteries to the brain.
This is the finding of an article published in the April issue of Public
Library of Science Medicine by MESA Air Researcher Dr. Sara Adar of the University of
Dr. Adar and her team conducted this study thanks to participants who allowed the MESA Air
team to do pollution sampling in their homes.
This home air sampling was optional, but many participants agreed to it.
This allows researchers to answer important questions like the one in this study.
Dr. Adar looked at ultrasound scans of MESA Air participants that measure the thickness of
the walls of the common carotid artery.
The carotid arteries are located in the sides of your next (see figure below).
They supply oxygen-rich blood to your brain face, scalp, and neck. The ultrasound looks
for build-up of a substance called plaque in your carotid arteries.
This waxy stuff can build up in the walls of the arteries.
When this happens, it is called carotid artery disease.
Over time, plaque can harden, narrowing the carotid arteries and reducing blood
flow to the brain. If the plaque gets too big, blood flow to the brain can be totally cut
off, causing a stroke. If the plague cracks, it may cause a blood clot.
This could also travel to the brain and cause a stroke.
Lots of plaque in the carotid artery can also mean there is lots of plaque in
other important arteries. This could include the ones that feed your heart.
If they are blocked, this could lead to a heart attack.
Results from MESA Air show that people living in areas with higher levels of air pollution
have thicker carotid artery walls than people living in areas with cleaner air. The arteries
of people in more polluted areas also thickened faster over time, as compared to people
living in places with cleaner air. These findings might help to explain how air pollution
leads to problems like stroke and heart attacks.
Figure A shows the location of the right carotid artery in the head and neck.
Figure B is a cross-section of a normal carotid artery that has normal blood flow.
Figure C shows a carotid artery that has plaque buildup and reduced blood flow.
Adar SD, Sheppard L, Vedal S, Polak JF, Sampson PD, Diez Roux AV, Budoff M,Jacobs DR Jr, Barr RG,
Watson K, Kaufman JD. Fine particulate air pollution and the progression of carotid intima-medial
thickness: a prospective cohort study from the multi-ethnic study of atherosclerosis and air pollution. PLoS Med. 2013;10(4):e1001430.