Exposure to particulate air pollution also may be
associated with acute heart attack. This may be due, in part to a sympathetic
stress response, as detected by changes in heart rate variability, the
production of cytokines, and an increased vulnerability to plaque rupture
(Circulation. 2001;104:986, J Am Coll
Cardiol. 2002;39:935, Circulation. 2004;109:2655).
In a study of 772 patients with an acute heart
attack the risk of an heart attack was increased in the two hours after
exposure to elevated levels of fine particles in the air (odds ratio 1.48
compared with low levels of fine particles); this effect lasted for up to 24
hours after exposure (Circulation. 2001;103:2810).
In a systematic review and meta-analysis of data
from 34 studies, carbon monoxide, nitrogen dioxide, sulfur dioxide, and small
particulate matter (less than 10 microns and less than 2.5 microns) were all
associated with an increased risk of heart attack with the overall population
attributable risk ranging from 1 to 5 percent (JAMA. 2012;307(7):713).
Short-term particulate exposures contributed to
acute coronary events (heart attack) in patients with underlying coronary
artery disease. Individuals with stable presentation and those with
angiographically demonstrated clean coronaries are not as susceptible to
short-term particulate exposure. (Circulation. 2006;114(23):2443).
PM1, PM2.5 and PM10 are risk factors of
all-cause, cardiovascular, stroke, respiratory, and COPD mortality.
PM1 accounts for the vast majority of short-term PM2.5- and PM10-induced
mortality. Smaller size fractions of PM have a more toxic mortality impacts.
Dr KK Aggarwal
Padma Shri Awardee
President Elect Confederation of Medical
Associations in Asia and Oceania (CMAAO)