(This sheet is summary of links to the above website as of July 2004)

Passive Smoking

Background

Exposure to environmental tobacco smoke, also known as "passive smoking" occurs from breathing in other people's smoke. It comes from both the burning end of a cigarette and from the smoke breathed out by a smoker.

Smoking is specifically prohibited in food preparation areas, public transport, theatres, cinemas, elevators, aircraft and airports. However, tobacco smoke continues to be an important source of exposure to toxic air contaminants in homes, public places and some workplaces.

Passive smoking is a hazard to health. Major reports on passive smoking which have comprehensively reviewed cardiovascular disease consistently find that passive smoking causes heart disease in non-smokers living with smokers.

Evidence

The National Health and Medical Research Council¹ in Australia first reported an increased risk of cardiovascular disease from passive smoking in 1987.

Reviews of the more than 15 epidemiological studies since 1985 have consistently reported between a 24% to 30% increased risk of fatal and non-fatal cardiac events in non-smokers living with smokers.

The Californian Environmental Protection Agency² concluded that passive smoking is a cause of heart disease death and acute and chronic heart disease morbidity in 1997. In the same year the National Health and Medical Research Council³ estimated that the risk of heart attack or death from coronary heart disease is 24% higher in non-smokers living with a smoker. By 1998 the Report of the Scientific Committee on Tobacco and Health⁴ had also concluded that passive smoking is a cause of heart disease.

Research on the effect of exposure in workplaces is scarce although Kawachi et al⁵ reported a doubling of the risk of coronary heart disease among non-smoking women regularly exposed to passive smoking at work. Doll⁶ emphasises the substantial risk of ischaemic heart disease for older workers because the disease is so common in later life.

The effect of passive smoking on cardiovascular health is very important in terms of public health because environmental exposure to tobacco smoke and disease of the heart and blood vessels are both very common in many populations. This means that even a small increase in risk related to passive smoking would translate into a large number of additional cases of heart attack, stroke and premature death³.

Because there are multiple risk factors for cardiovascular disease, non-smokers with high blood pressure, high cholesterol and exposed to passive smoking are likely to be at an even greater risk of developing heart disease.

Patients with established heart disease who are exposed to carbon monoxide, a major component of tobacco smoke, may experience exacerbated symptoms of angina and cardiac dysrhythmias (disturbances of the heart's electrical rhythm) ³.

Considering that smoking is a major risk factor for stroke and peripheral vascular disease, it is also likely that passive smoking increases the risk for these diseases, although there is an insufficient number of studies available to make this conclusion at present.

Many elements, including carbon monoxide, nicotine, polycyclic aromatic hydrocarbons, and other, not fully specified substances in cigarette smoke cause the effects of passive smoking on the cardiovascular system⁷.

The damage caused by passive smoking is of a short term and long-term nature. Detailed scientific reviews^{7, 8} point to a variety of mechanisms for the effects of passive smoking. This may include platelet aggregation, damage to arterial endothelium, thrombus formation, acceleration of atherosclerotic plaque formation and reduced oxygen for the heart, evidenced by reduced exercise capability of both healthy people and those with heart disease. There is also evidence for the effects of passive smoking occurring from an early age with the observation of damage of the artery lining in healthy young adults.⁹

The large effect of passive smoking on the risk of ischaemic heart disease (compared to smoking) is thought to be from a non-linear dose response relationship, with platelet aggregation thought to be the culprit.^{4 ,10}

Few reports have examined whether elimination of passive smoking is followed by a reduction in cardiovascular disease. Law et al¹⁰ estimated that reversal of the effect would reduce the risk of ischaemic heart disease by about as much as taking aspirin, or by what many people could achieve through dietary change. Certainly the cessation of cigarette smoking is associated with a reduced risk of cardiovascular disease, and considering the similar biological mechanisms it would not be unreasonable to expect similar health benefits from the elimination of exposure to passive smoking.

Reducing the hazard of passive smoking is often discussed in terms of a "hierarchy of control" where elimination (smoking prohibition) or isolation (separate room for smoking with separate mechanical ventilation) are recommended. ^{11, 12} Major reports on mechanical ventilation and passive smoking highlight the practical difficulties of controlling tobacco smoke odour, including impractically huge ventilation rates, prohibitively expensive equipment and maintenance requirements.^{11, 12, 13}

NHF position

1. Passive smoking is an important and avoidable cause of heart disease, increasing a person's risk by about 25%.
2. Everyone should be able to go about their daily lives without involuntary exposure to other people's smoke. Therefore, all workplaces, homes, cars, enclosed indoor public places and outdoor restricted public places (such as sports stadia) should be smoke- free.

Public Health Policy
1. Comprehensive smoke-free policies for all public places and workplaces are preferred because they have the advantage of simplicity, clarity and promoting health for everyone.
2. Protecting the public from exposure to passive smoking requires a systematic regulatory response.
3. Mechanical ventilation of indoor spaces is neither an adequate or affordable response to passive smoking.
4. In the event that legislation allows for the phasing-in of smoke-free requirements in certain areas of the hospitality industry, a definitive end-point for all premises to be smoke-free must be included.

   Education

5. Implementation of legislative requirements to achieve smoke-free workplaces and public places should be accompanied by a comprehensive public education campaign with adequate resources.
6. The hazard in the home requires greater public education so that smokers recognise the risk to which they expose members of their family.
7. It is important that doctors advise families of patients with known heart and blood vessel disease to not smoke inside their homes or in enclosed spaces. Patients should also avoid venues that permit smoking.

1. National Health and Medical Research Council. Effects of Passive Smoking on Health. Report of the NHMRC Working Party on the effects of passive smoking on health. Canberra: Australian Government Publishing Service, 1987.
2. California Environmental Protection Agency, Office of Environmental Health Hazard Assessment. Health effects of exposure to environmental tobacco smoke. Sacramento: California Environmental Protection Agency, 1997. (http://www.calepa.cahwnet.gov/oehha/docs/finalets.htm)
3. National Health and Medical Research Council. The health effects of passive smoking. A Scientific Information Paper. Commonwealth of Australia. November 1997.(http://www.health.gov.au/nhmrc/advice/nhmrc/)
4. Report of the Scientific Committee on Tobacco and Health. UK Department of Health. 1998. (http://www.open.gov.uk/doh/public/scoth.htm)
5. Kawachi I, Colditz A, Speizer F, et al. A prospective study of passive smoking and coronary heart disease. Circulation 1997; 95:2374-9
6. Doll R. Effect of environmental tobacco smoke on adults. In: Stockwell, T (Ed.). Drug Trials and Tribulations: Lessons for Australian Policy. Proceedings of an international symposium. National Centre for Research into the Prevention of Drug Abuse. Curtin University of Technology, February 6 1998. Perth: National Centre for Research into the Prevention of Drug Abuse, June 1998.
7. Glantz SA, Parmley WW. Passive smoking and heart disease, mechanisms and risk. JAMA 1995;273:1047-53
8. Glantz SA, Parmley WW. Passive smoking and heart disease, epidemiology, physiology, and biochemistry. Circulation 1991; 83:1-12
9. Celermajer DS, Adams MR, Clarkson P, et al. Passive smoking and impaired endothelium-dependent arterial dilation in healthy young adults. NEJM 1996; 334:150-4.
10. Law M, Morris J, Wald N. 1997. Environmental tobacco smoke exposure and ischaemic heart disease: an evaluation of the evidence. BMJ 1997; 315:973-80
11. Report by the NSW Passive Smoking Taskforce to the NSW Minister for Health. Passive Smoking in the Hospitality Industry - Options for Control. NSW Health Department. February 1997.
12. Brown S K. 1997. Indoor Air Quality, Australia: State of the Environment Technical Paper Series (Atmosphere). Department of the Environment, Sport and Territories, Canberra.
13. Task Force on Passive Smoking: Report of the WA Task Force on Passive Smoking in Public Places. Health Department of WA. October 1997.

A position statement prepared by the National Tobacco Control Committee for the National Heart Foundation

October 1998/PP-546
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