3.1 Smoking and heart disease

Last updated:July 2019
Suggested citation: Briffa, T, Greenhalgh, EM, & Winstanley, MH. 3.1 Smoking and heart disease. In Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2019.  Available from  http://www.tobaccoinaustralia.org.au/chapter-3-health-effects/3-1-smoking-and-heart-disease


Cardiovascular disease (CVD) covers all disease processes of the heart and blood vessels. In 2015, 45,613 Australians died from CVD, accounting for just under one third (29%) of all deaths in that year. CVD is the second largest contributor to the burden of disease in Australia after cancer—estimated at 14% and 18% respectively in 2015. 1

Premature CVD is highly preventable. Tobacco smoking, raised blood pressure, elevated blood cholesterol, insufficient physical activity, overweight and obesity, poor nutrition, drinking at harmful levels and diabetes are major preventable risk factors for CVD. In 2015, 11.5% of the burden of cardiovascular disease in Australia was attributable to tobacco use, 1 and smoking increases the risk of almost all types of CVD. 2 A major Australian study published in 2019 estimated that mortality from cardiovascular disease is almost three times higher in current versus never smokers, and that at least 38% of cardiovascular deaths prior to age 65 and about 16% of all cardiovascular deaths in Australia can be attributed to smoking. 2 Although the greatest burden is seen in middle age, smoking is a strong independent risk factor of cardiovascular events and mortality even at older age, advancing cardiovascular mortality by more than five years among smokers over 60. 3 While smoking 25 or more cigarettes per day increases a person’s risk of dying of CVD almost five-fold, even ‘light’ smoking (4–6 cigarettes per day) doubles a person’s risk. 2  Socio-economic and psychosocial factors, such as low income, unemployment, remoteness, depression and social isolation are also associated with the development of CVD. In Australia, CVD is more common among disadvantaged groups, including Aboriginal and Torres Strait Islander peoples. 1, 4

Cigarette smoking contributes to CVD in a number of ways. Toxic products from cigarette smoke, in particular nicotine and carbon monoxide (CO), circulate in the bloodstream, interfering with the efficient working of the endothelium (the inner cellular layer of the arterial wall), eliciting blood fat abnormalities and impairing glucose regulation. Each effect is implicated in the development of atherosclerotic lesions (collections of cholesterol, fat and other matter) in the arterial walls. These collections narrow the arteries, gradually impairing blood flow, and making the arteries harder, less elastic, and more liable to rupture. The process leading to atherosclerosis—plaque (fatty streaks) deposited within the inner layers of the arteries—is slow and complex, often starting in childhood and progressing with age. Smoking also has a direct effect on platelets (blood cells involved in the clotting process), leading to increased activation and stickiness. This in turn causes an increased risk of thrombosis, or development of blood clots. 5

Smoking a cigarette also temporarily increases heart rate and blood pressure and affects the ability of the heart to contract. These circulatory changes result in increased work for the heart muscles, which in turn raises the body’s demand for oxygen. At the same time, the body is deprived of oxygen through the effects of CO on reducing transport oxygen. The resulting imbalance in oxygen supply and demand promotes the complications of atherosclerosis. These include ischaemia (lack of oxygen due to poor blood supply), with resultant angina pectoris (chest pain or tightness) or myocardial dysfunction (poor heart muscle function). 5, 6

While nicotine and CO in tobacco smoke are strongly implicated in the processes leading to development of CVD, other chemicals may also be involved. 5 There is now strong evidence that exposure to secondhand cigarette smoke is also a cause of coronary heart disease in non-smokers (see Chapter 4).

Quitting smoking at any age substantially reduces a person’s risk of CVD, with those quitting by age 45 avoiding almost all of the excess risk. For the most common types of CVD in Australia, the risks for smokers who quit prior to the age of 35 are comparable to people who have never smoked. In addition, smokers who quit prior to age 55 are at no greater risk of death from all major CVD, compared to never smokers. 2 Even at older ages, quitting smoking is beneficial in reducing the cardiovascular excess risk. 3

3.1.1 Coronary heart disease

Coronary heart disease (CHD), also known as ischaemic heart disease, is the most common form of CVD, and the most common cause of sudden death in Australia. 7 It occurs when the arteries supplying the heart become progressively narrowed by a fatty fibrous plaque or atheroma. This reduces the blood flow, forcing the heart to work harder to compensate, and can lead to symptoms of angina. If the plaque breaks up, a blood clot may form, blocking the artery completely. If not promptly treated, this can lead to death of vital heart muscle due to oxygen starvation (termed acute myocardial infarction or heart attack), or, in the worst case, sudden death. 5

Smoking is a cause of CHD, 8 with the most recent Australian estimates showing that current smokers are 1.7 times as likely to develop CHD, and 2.5 times as likely to experience a heart attack, compared with never smokers. 2 The risk of both increases with heaviness of smoking. 2 Smoking up to fourteen cigarettes per day more than doubles a person’s risk of death from CHD, while smoking more than 25 cigarettes per day increases a person’s risk more than five-fold. 2 In 2015, tobacco use was responsible for 13.9% of the disease burden due to CHD in Australia. 1 Smoking in adolescence and young adulthood is also associated with an increased risk of coronary artery atherosclerosis in adulthood. 9

Smokers who have CHD are more likely to die of the disease than non-smokers with the disease. A 2013 study looking at 50-year trends in smoking-related mortality found that although overall death rates from CHD have declined, these declines were proportionately larger for never smokers than for current smokers. The mortality rate was more than three times higher for current smokers compared with never smokers aged between 55 and 74, with two thirds of the deaths among smokers being attributable to their smoking. There was also a significantly increasing risk of CHD mortality for both men and women with increasing consumption through 40 or more cigarettes per day. 10 The heaviest burden of excess death due to tobacco-caused CHD is felt in early middle age. In Australia, there is around a tripling in the risk of heart attack in current versus never smokers aged 45–64, compared with an increased risk of 1.7 times for smokers at age 80 and over. 2  The effects of active smoking compared with no exposure are likely to be underestimated because most CVD studies have not excluded persons who had secondhand smoke exposure from the comparison group.

Lower tar and nicotine cigarettes have not been shown to reduce the incidence of CHD due to smokers increasing the number of cigarettes smoked per day or by taking deeper, faster, more or longer puffs. Thus, such cigarettes do not provide a lower risk alternative for smokers who cannot or do not wish to quit. 5

The risks of myocardial infarction and death from CHD are lower among former smokers than among continuing smokers. The 2010 report of the US Surgeon General states that the risk halves within the first year and takes between 10–14 years before it approaches that of a lifetime non-smoker. 5 The International Agency for Research on Cancer 11 describes the benefits of quitting more conservatively:

‘... there is a substantial reduction in risk of CHD compared with that of continuing smokers with the first two to four years of smoking abstinence, followed by a slower decline of risk, with risk approaching that of never smokers in fifteen to twenty years. For methodological reasons, the assessment of risk reduction is problematic within the first two years of cessation.’(p 342)

The International Agency for Research on Cancer also cites a reduced risk of 35% within two to four years for persons already suffering from CHD, and says studies on subjects without diagnosed CHD are ‘compatible with this conclusion and point toward similar relative risk reduction.’ 11 (p 336). Australian research published in July 2019 found no significant elevations in the incidence of CHD in past smokers who quit by age 35, and no significant elevations in mortality from CHD in past smokers who quit by age 55. 2

3.1.2 Cerebrovascular disease (stroke)

A stroke occurs when blood flow to the brain is interrupted, leading to injury or death of brain tissue. This occurs most commonly because of arterial blockage caused by atherosclerosis or a blood clot, an event known as an ischaemic stroke. Happening less often, but more likely to be fatal when it does arise, is a haemorrhagic stroke, in which bleeding occurs from a leaking or ruptured arterial wall at a point weakened by atherosclerosis. Sometimes the artery stretches at the site of weakness, causing it to balloon out, forming an aneurysm. The bigger the aneurysm, the more likely it is to rupture, causing haemorrhage and a resultant stroke.

One in five people experiencing their first stroke episode will die within four weeks, and one in three will die within 12 months. Among the people who survive the first month after their first-ever stroke, about half will survive five years. 12 Stroke is a major cause of disability in Australia. By the end of the first year following a stroke, about half of stroke survivors still require assistance with daily activities. 12

Smoking is an important cause of stroke, with the risk of having a stroke rising with the amount of tobacco smoked. 5, 13 In Australia, current smokers are more than twice as likely to have cerebrovascular disease compared with never smokers. 2 In 2015, tobacco use was responsible for 10.8% of the disease burden due to stroke. 1

As with CVD, the impact of stroke caused by tobacco is greatest among the middle aged. In Australia in 2004–05, 40% of all deaths due to stroke in men aged between 35 and 39 were caused by smoking. The greatest impact occurred in women aged 40–44, among whom 35% of all stroke deaths were due to tobacco. 14 Research has shown that the risk of having a stroke decreases steadily after quitting smoking,  with an Australian study showing that those who quit prior to age 35 are at comparable risk to those who never smoked. 2

3.1.3 Atherosclerotic peripheral vascular disease

Atherosclerotic peripheral arterial disease (PAD) occurs when blockages within the blood vessels prevent proper blood circulation. PAD most commonly occurs in the legs and feet, but it can also develop in the arms and hands. This may result in severe pain (claudication), especially when physically active. PAD can lead to death of part of the limb. Amputation may be necessary for relief of pain, and to prevent the development of gangrene. Given that it’s the same atherosclerotic disease process, it is not uncommon for individuals with PAD to die from heart attack or stroke. 15

Smoking is a cause of PAD, with current smokers having five times the risk of developing PAD compared to people who have never smoked. 2 In 2015, tobacco use was responsible for 8.9% of the disease burden due to PAD in Australia. 1 There is a strong dose–response relationship between the number of cigarettes smoked and the likelihood of developing PAD even after adjustment for other CVD risk factors. 5 Australian research published July 2019 found that smokers of 1–14 cigarettes per day were 3.5 times as likely to experience a PAD event compared with never smokers, while those who smoked 25 or more cigarettes per day were more than seven times as likely. 2 In Australia in 2004–05, about 37% of all deaths due to PAD in males aged over 35 were attributable to smoking, as were 30% of all PAD deaths in women aged over 35. 14

Although quitting smoking at any age reduces a person’s risk of developing PAD, the risk remains 1.5 to two times higher among those who quit after age 35. Quitting prior to age 35 reduces a person’s risk to that of someone who has never smoked. 2 Patients who suffer vascular-related leg pain are less likely to suffer serious obstruction of the arteries in their legs if they quit. Quitting smoking also reduces the risk of re-occlusion after peripheral vascular surgery. 16, 17

3.1.4 Abdominal aortic aneurysm

Abdominal aortic aneurysm is a weakening of the wall of the aorta (the major artery carrying oxygenated blood from the heart to the body) in the region below the diaphragm. The weakening occurs as a result of atherosclerotic lesions developing in the aortic wall. The wall may eventually stretch and then leak or burst. Abdominal aortic aneurysm is frequently fatal. 5

Smoking is a cause of abdominal aortic aneurysm, the risk rising with increased exposure to tobacco smoke. 5 A meta-analysis published in 2018 concluded that current smokers have almost five times the risk of abdominal aortic aneurysm, 18 while an Australian study published July 2019 found that current smokers are six times as likely to develop abdominal aortic aneurysm compared with never smokers. 2 Further, active smoking in adolescence and young adulthood can cause early abdominal aortic atherosclerosis in young adults. 9 Smoking is one of the few currently modifiable risk factors for this disease. With increasing time after stopping smoking, the risk of developing an abdominal aneurysm appears to slowly decline. 5

3.1.5 Sudden cardiac death

Sudden cardiac death describes death occurring due to sudden, unexpected loss of heart function. Most sudden death is due to CVD, in particular CHD accompanied by smoking. Cardiac dysrhythmias (irregular muscular contractions of the heart, also referred to as cardiac arrhythmias) also cause sudden cardiac death. The US Surgeon General’s reports 5, 8, 19, 20 and a meta-analysis published in 2018 21 have concluded that smokers have a three-fold greater risk of suffering sudden cardiac death than non-smokers. Australian research has estimated that current smokers are 2.4 times as likely to experience cardiac arrest compared with never smokers. 2 Importantly, cigarette smoking may be the only modifiable risk factor for sudden cardiac death in the presence or absence or CHD. 5

In Australia it is estimated that smoking causes 30–40% of all deaths due to cardiac dysrhythmias in men aged 35–59, and about one-third of all deaths due to cardiac dysrhythmias in women aged 35–44. 14

3.1.6 Congestive heart failure

Congestive heart failure (CHF) occurs when the heart becomes less able to pump blood through the body effectively. The heart may become enlarged or thicken, and fluid may collect in lungs (causing shortness of breath) or in other parts of the body (causing swelling or weight gain). CHF usually occurs in individuals with a history of heart problems such as high blood pressure or coronary heart disease. 22 As well as contributing to the disease processes that primarily lead to CHF, smoking is an independent risk factor for CHF. 20

CHF sufferers experience high levels of disability and have a reduced life expectancy. 20 Australian research has found that current smokers have more than double the risk of developing heart failure compared with those who have never smoked. The risk becomes almost four-fold among smokers who smoker 25 or more cigarettes per day. 2 In Australia, it is estimated that smoking causes 30‒40% of all deaths due to CHF in men aged 35‒59, and about one-third of all deaths due to CHF in women aged 35‒44. 14 Quitting smoking drastically reduces the risk of heart failure, with greater reductions among those who quit at younger ages. 2, 23

3.1.7 Paroxysmal tachycardia

Paroxysmal tachycardia is a type of arrhythmia (irregular heartbeat) which begins and ends abruptly, where the heart is beating abnormally fast. It can cause an adult’s heart rate to increase from between 60 and 100 beats per minute (bpm) to between 130 and 230 bpm. Recent Australian research found, for the first time, a significant increase in the risk of paroxysmal tachycardia hospitalisation or death in current versus never smokers. Current smokers were 1.5 times as likely to develop paroxysmal tachycardia compared with never smokers. 2

3.1.8 Atrial fibrillation

Atrial fibrillation is a type of abnormal heart rhythm (arrhythmia), which starts in the upper chambers of the heart (the atria) and causes them to quiver (fibrillate), instead of beating normally. This can result in the heart not pumping blood as efficiently as it should. Past research on the link between smoking and atrial fibrillation has been inconsistent; however recent Australian research has found that smoking is associated with an increased risk of atrial fibrillation in a dose-dependent matter. Two recent meta-analyses, 24, 25 along with Australian research published in 2019, 2 concluded that current smokers are 1.3 times as likely to develop atrial fibrillation compared to never smokers.

3.1.9 Other types of heart disease

Along with the heart diseases listed above, the major Australian study published in 2019 concluded that current smoking increases the risk of virtually all CVD subtypes, at least doubling the risk of many. 2 Figure 3.1.1 shows the relative risks (i.e., how many times as likely a current smoker is to develop the CVD subtype, compared with those who have never smoked) for specific CVD subtypes that were significantly elevated in current smokers.

Figure 3.1.1
Relative risks for specific CVD subtypes (level 3 ICD-10-AM codes), in current versus never smokers (%) 

Source: Banks E, et al., Fig. 2 2
Note: Only showing subtypes with risks that were significantly elevated among smokers


Relevant news and research

For recent news items and research on this topic, click  here. ( Last updated September 2019)

References

1.         Australian Institute of Health and Welfare. Australian burden of disease study: Impact and causes of illness and death in Australia 2015. Australian Burden of Disease, Canberra: AIHW, 2019. Available from: https://www.aihw.gov.au/reports/burden-of-disease/burden-disease-study-illness-death-2015/contents/summary.

2.         Banks E, Joshy G, Korda RJ, Stavreski B, Soga K, et al. Tobacco smoking and risk of 36 cardiovascular disease subtypes: Fatal and non-fatal outcomes in a large prospective Australian study. BMC Medicine, 2019. Available from: https://doi.org/10.1186/s12916-019-1351-4

3.         Mons U, Muezzinler A, Gellert C, Schottker B, Abnet CC, et al. Impact of smoking and smoking cessation on cardiovascular events and mortality among older adults: Meta-analysis of individual participant data from prospective cohort studies of the chances consortium. British Medical Journal, 2015; 350:h1551. Available from: http://www.ncbi.nlm.nih.gov/pubmed/25896935

4.         Australian Institute of Health and Welfare. Australian burden of disease study: Impact and causes of illness and death in Aboriginal and Torres Strait Islander people 2011. Australian Burden of Disease Study series no. 6. Cat. no. BOD 7, Canberra: AIHW, 2016. Available from: http://www.aihw.gov.au/publication-detail/?id=60129557110

5.         US Department of Health and Human Services. How tobacco smoke causes disease: The biology and behavioral basis for smoking-attributable disease. A report of the US Surgeon General, Atlanta, Georgia: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2010. Available from: http://www.surgeongeneral.gov/library/tobaccosmoke/report/index.html.

6.         Benowitz N. Drug therapy: Pharmacologic aspects of cigarette smoking and nicotine addiction. New England Journal of Medicine, 1988; 319(20):1318–30. Available from: https://www.ncbi.nlm.nih.gov/pubmed/3054551

7.         Australian Institute of Health and Welfare. Trends in cardiovascular deaths. Bulletin no. 141, Cat. no. AUS 216 Canberra: AIHW, 2017. Available from: https://www.aihw.gov.au/reports/heart-stroke-vascular-disease/trends-cardiovascular-deaths/contents/table-of-contents.

8.         US Department of Health and Human Services. The health consequences of smoking - 50 years of progress. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. Available from: http://www.surgeongeneral.gov/library/reports/50-years-of-progress/.

9.         US Department of Health and Human Services. Preventing tobacco use among young people: A report of the Surgeon General. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2012. Available from: http://www.cdc.gov/tobacco/data_statistics/sgr/2012/.

10.       Thun MJ, Carter BD, Feskanich D, Freedman ND, Prentice R, et al. 50-year trends in smoking-related mortality in the United States. The New England Journal of Medicine, 2013; 368(4):351-64. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3632080/

11.       International Agency for Research on Cancer. Reversal of risk after quitting smoking. IARC handbooks of cancer prevention, tobacco control, 11 Vol. 11.Lyon, France: IARC, 2007. Available from: http://apps.who.int/bookorders/anglais/detart1.jsp?sesslan=1&codlan=1&codcol=76&codcch=22.

12.       Senes S. How we manage stroke in Australia. Cardiovascular disease series no.24, cat. no. CVD 31.Canberra: AIHW, 2006. Available from: http://www.aihw.gov.au/publication-detail/?id=6442467815.

13.       Doll R, Peto R, Boreham J, and Sutherland I. Mortality in relation to smoking: 50 years' observations on male British doctors. British Medical Journal, 2004; 328:1519–27. Available from: https://www.bmj.com/content/328/7455/1519

14.       Collins D and Lapsley H. The costs of tobacco, alcohol and illicit drug abuse to Australian society in 2004/05. P3 2625. Canberra: Department of Health and Ageing, 2008. Available from: http://www.nationaldrugstrategy.gov.au/internet/drugstrategy/publishing.nsf/Content/mono64/$File/mono64.pdf.

15.       Australian Institute of Health and Welfare and National Heart Foundation of Australia. Heart, stroke and vascular diseases—Australian facts 2004. Cardiovascular disease series no. 22, cat. no. CVD 27.Canberra: AIHW and NHFA, 2004. Available from: http://www.aihw.gov.au/publications/cvd/hsvd04/hsvd04.pdf.

16.       U.S. Department of Health and Human Services. The health consequences of smoking: 50 years of progress. A report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014, Printed with corrections, January 2014. Available from: http://www.surgeongeneral.gov/library/reports/50-years-of-progress/full-report.pdf.

17.       US Department of Health and Human Services. The health benefits of smoking cessation. A report of the Surgeon General. Atlanta, GA: Centers for Disease Control, Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 1990. Available from: http://profiles.nlm.nih.gov/NN/B/B/C/V/_/nnbbcv.pdf.

18.       Aune D, Schlesinger S, Norat T, and Riboli E. Tobacco smoking and the risk of abdominal aortic aneurysm: A systematic review and meta-analysis of prospective studies. Sci Rep, 2018; 8(1):14786. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30283044

19.       US Department of Health and Human Services. The health consequences of smoking: Cardiovascular disease. Rockville, Maryland: Public Health Service, Office on Smoking and Health, 1983. Available from: http://www.cdc.gov/tobacco/data_statistics/sgr/pre_1994/index.htm.

20.       US Department of Health and Human Services. The health consequences of smoking: A report of the Surgeon General. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2004. Available from: http://www.cdc.gov/tobacco/data_statistics/sgr/index.htm.

21.       Aune D, Schlesinger S, Norat T, and Riboli E. Tobacco smoking and the risk of sudden cardiac death: A systematic review and meta-analysis of prospective studies. Eur J Epidemiol, 2018. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29417317

22.       National Heart Foundation of Australia. Let's talk about heart failure. Canberra: NHFA, February 2003. Available from: http://www.nevdgp.org.au/info/heartf/pdfs/heartfailureinfosheet.pdf.

23.       Aune D, Schlesinger S, Norat T, and Riboli E. Tobacco smoking and the risk of heart failure: A systematic review and meta-analysis of prospective studies. European Journal of Preventive Cardiology, 2018:2047487318806658. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30335502

24.       Aune D, Schlesinger S, Norat T, and Riboli E. Tobacco smoking and the risk of atrial fibrillation: A systematic review and meta-analysis of prospective studies. European Journal of Preventive Cardiology, 2018:2047487318780435. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29996680

25.       Zhu W, Yuan P, Shen Y, Wan R, and Hong K. Association of smoking with the risk of incident atrial fibrillation: A meta-analysis of prospective studies. International Journal of Cardiology, 2016; 218:259-66. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27236125