Surprisingly small amounts of secondhand smoke can kill

Posted on Mon, 12 Oct 09

Despite the tobacco industry’s concerted effort to down play the hazards of second-hand smoke exposure (passive smoking) up to 75% of non-smokers have a greatly increased risk of coronary heart disease due to passive smoking (1). Even very low levels of exposure to cigarette smoke are remarkably detrimental. It is now clear that low exposure to tobacco smoke, such as passive smoking or in those who only smoke 1-2 cigarettes a day, acutely affects cardiovascular health in a way that is comparable to that of a heavy smoker (2). What is important is not how much tobacco smoke you are exposed to, but whether you are exposed to it at all.

The amount of smoke is not important

Passive smokers are only estimated to be exposed to 1% of the level of tobacco smoke of a 20 cigarettes a day smoker yet they experience a similar cardiovascular disease risk. The human cardiovascular system is exquisitely sensitive to the toxic effects of tobacco smoke. Within just 30 minutes of passive exposure to tobacco smoke, non-smokers experience significant cellular damage and dysfunction within the cardiovascular system (3). Unfortunately for smokers and non-smokers alike these acute effects go unnoticed and the first noticeable side effect of smoke exposure may be more significant, such as heart attack or death.

Smoking bans stop people dying

Several examples of strong government enforced smoking bans have resulted in large improvements in public health. A recent analysis of smoking bans in 5 different countries found that within the first year there was a 15% reduction in hospital admissions from heart attack and a continuing decline each year to a 36% decrease 3 years after the bans (4).

Every year 1 in 10 people (5 million people worldwide) die a premature death as a result of tobacco smoke (5). Importantly tobacco smoke no only harms the smoker but also those around them, particularly children who are powerless to protect themselves from the dangers of cigarette smoke. Passive smoke is particularly dangerous for children who have smaller airways, breathe more quickly, and take in 3 to 4 times as much air, and thus smoke, as adults (3).

References

1. Whincup PH, Gilg JA, Emberson JR, Jarvis MJ, Feyerabend C, Bryant A, Walker M, Cook DG. Passive smoking and risk of coronary heart disease and stroke: prospective study with cotinine measurement. BMJ. 2004; 329: 200–205

2. Barnoya J, Glantz SA. Cardiovascular effects of secondhand smoke: nearly as large as smoking. Circulation. 2005; 111: 2684–2698.

3. A. M. Tonkin, A. Beauchamp, and C. Stevenson. The Importance of Extinguishing Secondhand Smoke. Circulation, October 6, 2009; 120(14): 1339 - 1341.

4. Lightwood JM, Glantz S. Declines in acute myocardial infarction after smoke-free laws and individual risk attributable to secondhand smoke. Circulation. 2009; 120: 1373–1379.

5. The World Health Organisation. Why is tobacco a public health priority? 2009.