4.4 Cardiovascular disease and secondhand smoke

Show / hide chapter menu

4.1 Background

4.2 What is secondhand smoke?

4.3 What is in secondhand smoke?

4.4 Cardiovascular disease and secondhand smoke

4.5 Lung cancer and secondhand smoke

4.6 Cancers of other sites

4.7 Health effects of secondhand smoke for infants and children

4.8 Effects of secondhand smoke on the respiratory system in adults

4.9 Secondhand smoke and pregnancy

4.10 Secondhand smoke and increased risk of infectious disease

4.11 Secondhand smoke and diabetes

4.12 Population prevalence of exposure to secondhand smoke in the home

4.13 Estimates of morbidity and mortality attributable to secondhand smoke

4.14 Public attitudes to secondhand smoke

Acknowledgments

References

4.4.1 Coronary heart disease

Exposure to secondhand smoke is a cause of coronary heart disease (also known as ischaemic heart disease) in non-smokers.19, 20, 30

Secondhand smoke affects the cardiovascular system in non-smokers by multiple mechanisms, similar to those experienced by active smokers.20 Secondhand smoke activates blood platelets, which increases the risk of thrombosis, and damages the cellular lining of the arteries, which promotes atherosclerosis.20, 31 Secondhand smoke also affects the ability of blood vessels to expand and contract, and changes lipoprotein profiles, impairing the body's ability to prevent or obstruct the progression of atherosclerosis.31 Other mechanisms mediated by secondhand smoke that contribute to cardiovascular disease include increased oxidative stress and decreased antioxidant defence, infection and inflammation, decreased energy production in the heart muscle, and a decrease in the parasympathetic output to the heart.31 Most of these responses occur rapidly following exposure.32 Where underlying cardiovascular disease already exists, exposure to secondhand smoke exacerbates the condition. Individuals with underlying diabetes, vascular disease or hypertension are at greater risk of harm due to secondhand smoke.19

Due to the extreme sensitivity of the cardiovascular system, comparatively low exposures to secondhand smoke can cause a disproportionately high amount of damage. Even brief exposures to secondhand smoke—from minutes to hours—may have almost as great an effect (up to 90%) on the cardiovascular system of non-smokers as active smoking has on the cardiovascular system of smokers.31 It is estimated that exposure to secondhand smoke increases the risk of an acute heart disease event in the non-smoker by about one quarter to one third, although a non-smoker's actual exposure to tobacco smoke is far less than that of the active smoker.18, 20, 33, 34 British research suggests that taking into account all sources of exposure, secondhand smoke may account for an excess risk of up to 60% for coronary heart disease in heavily exposed non-smokers, a rate similar to that of active smokers of up to 10 cigarettes per day.35

4.4.2 Stroke

Current evidence suggests that secondhand smoke may contribute to an increased risk of stroke, through encouraging atherosclerosis in the carotid and large arteries of the brain, and damaging arteries within the brain. However further research is required before this finding can be confirmed.19, 20