Climate change, air pollution and cardiovascular disease
To the Editor:
With great change of climate in the 21st century, this influence on
human health has been observed globally. Of note, industrial gas waste
is blamed for the increase of temperature and is toxic to human beings.
Recently, a number of review articles were published for addressing the
relationship between cardiovascular disease including myocardial
infarction and stroke and air pollution.1, 2 As is known, the severity of
air pollution is inversely associated with colder temperature, and less
windy and rainy weather.3 Previously, a number of population-based studies
have demonstrated that cardiovascular events are more common in winter and
on colder days, independent of season.4,5 The mechanisms underlying acute
vascular events may reflect a cold-induced hypercoagulopathy status for
thrombus propagation and is related to the hazardous effect of wintertime
respiratory infection.6 Accordingly, an interaction of air pollution and
cold temperature should be emphasized in the subtropical area with a
paradoxical change in temperature. In this regard, Keatinge and Donaldson
used multiple regression analysis of mortality for middle-aged persons on
weather factors and pollutants (SO2, CO and smoke) in London.3 They found
that cold weather is associated with 2.77 excess deaths per million during
24 days following 1 Celsius degree fall for 1 day, but no net excess
deaths with the concentrations of pollutants.3 Therefore, change of
climate may lead to up and down of the cardiovascular events worldwide
beyond the conventional factors. With the warm-up of the earth, the issue
of a rise of infectious disease has been emerged. However, a further
ecological study should focus on the interactions among climate change,
air pollutants and cardiovascular disease.
1. Nawrot TS, Perez L, K?nzli N, Munters E, Nemery B. Public health
importance of triggers of myocardial infarction: a comparative risk
assessment. Lancet. 2011 ; 377: 732-740
2. Mateen FJ, Brook RD. Air pollution as an emerging global risk factor
for stroke. JAMA. 2011; 305:1240-1241.
3. Keatinge WR, Donaldson GC. Mortality related to cold and air pollution
in London after allowance for effects of associated weather patterns.
Environ Res. 2001; 86:209-216.
4. Marchant B, Ranjadayalan K, Stevenson R, Wilkinson P, Timmis AD.
Circadian and seasonal factors in the pathogenesis of acute myocardial
infarction: the influence of environmental temperature. Br Heart J.
5. Spencer FA, Goldberg RJ, Becker RC, Gore JM. Seasonal distribution of
acute myocardial infarction in the second National Registry of Myocardial
Infarction. J Am Coll Cardiol. 1998; 31:1226-1233.
6. Woodhouse PR, Khaw KT, Plummer M, Foley A, Meade TW. Seasonal
variations of plasma fibrinogen and factor VII activity in the elderly:
winter infections and death from cardiovascular disease. Lancet.1994;
Competing interests: No competing interests