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Smoking and stroke

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What is a stroke?

Blood is supplied to the brain through blood vessels called arteries. A stroke occurs when an artery to the brain is suddenly blocked or bleeds.1 Blood supply to the brain can be disrupted by a blood clot or blockage by plaque in the artery, or because the artery breaks or bursts.2, 3 Bits of plaque can also break off from your blood vessel walls and block one of your arteries.2 Due to lack of blood, the brain cells supplied by the artery cannot get the oxygen and nutrients they need. This may result in part of the brain dying leading to loss of brain function. This can affect movement, thinking, memory, personality, talking and swallowing.1, 4
Where blood supply is reduced then the cells either recover or die. Speedy treatment can help cells recover.3

There are two types of stroke:

Ischaemic stroke

About 85% of strokes are caused by the blockage of an artery in the neck or brain.

Haemorrhagic stroke

The rest are caused by bleeding into or around the brain.4


How common is stroke?


Stroke is the second leading cause of death in women and the third leading cause of death in men in Australia5. Over 11,000 Australians died as a direct result of stroke in 2007.5 An estimated 60,000 strokes happen every year in Australia - that's one every 10 minutes.5 In 2003, there were an estimated 346,700 survivors of stroke.4 One in five were aged under 60 years.1 About 40% of stroke survivors had a disability resulting from their stroke. The risk of stroke increases with age.4


Smoking causes stroke


In 2003, 577 Australians died from stroke due to tobacco smoking.6

People who smoke are about twice as likely to have a stroke than someone who has never smoked.2, 7, 8 Smoking increases the risk of both types of stroke.2 The more you smoke, the higher your risk of stroke.2,9 Women who smoke and use oral contraception are almost four times more likely to have a stroke than women who use neither.2 The risk increases with age.10, 11

People who smoke are more likely to have a stroke earlier than non-smokers. For example, smokers under 65 years old are around three times more likely to have a stroke than nonsmokers of the same age.8, 9 Smoking is a major cause of stroke in people under 65 years old.2,9

You can reduce your risk of stroke by stopping smoking.2 Other risk factors for stroke that can be controlled include high blood pressure, high cholesterol levels, poor diet, lack of exercise, obesity, diabetes, too much alcohol and irregular pulse (atrial fibrillation). The more risk factors you have, the higher your chances of having a stroke.4 However, smoking by itself increases your risk of stroke.2

How does smoking cause stroke?


There are over 4000 different types of chemicals in cigarette smoke.12 Once inhaled into the lungs, many of these chemicals pass through your lung walls, into your bloodstream and are carried around your body.2

Chemicals from smoke affect your blood, making it thicker, stickier and more likely to form clots.2, 7 They cause fatty material (plaque) to build up on your blood vessel walls faster. This process starts early and is evident in smokers in their teens and early twenties. Over time, the plaque slowly narrows and blocks your blood vessels making it difficult for your blood to circulate. Bits of plaque can break off from your blood vessel walls and block one of your arteries. Also, the build up of plaque makes your artery walls harder and less elastic, and more prone to break or burst allowing bleeding into the brain.2


Signs of stroke


The FAST test is an easy way to recognise if someone is having a stroke. FAST stands for Facial weakness, Arm weakness, Speech difficulty, Time to act.13

Using the FAST test involves asking three simple questions:

• Face - Can the person smile, has their mouth or eyes drooped?
• Arms - Can the person raise both arms?
• Speech - Can the person speak clearly and understand what you say?
• Time - Act FAST and call 000.

There can also be temporary or mini strokes (where symptoms disappear within 24 hours), known as transient ischaemic attacks (TIA).1 Around one in three people who have a TIA will have a stroke, and for about one in eleven this will happen within the next week.4 Therefore, if you have a TIA you should see your doctor promptly.3


Stopping smoking reduces your risk of stroke


Your risk of stroke decreases steadily after you quit.2 Studies show that the risk of stroke in most ex-smokers becomes similar to people who have never smoked after five to fifteen years.7 However, one study shows that while the risk of stroke falls markedly among former heavy smokers (more than 20 cigarettes per day), their risk may remain higher than the risk for people who have never smoked for many years.14 Quitting smoking particularly benefits people with high blood pressure in regard to reducing their risk of stroke.2, 14

Switching to cigars or pipes has little effect on reducing your risk of stroke.2 Cutting down the number of cigarettes you smoke does not appear to reduce the risk of early death.15

Stopping smoking has both immediate and long-term health benefits

When you quit:

  • Within one day the level of carbon monoxide in your blood drops dramatically. You have
    more oxygen in your bloodstream.7
  • After eight weeks your blood is less thick and sticky, and your blood flow will improve.7, 16
    Your body is able to heal wounds better.17
  • After 16 weeks your level of good cholesterol has improved.2 This helps slow down the
    build up of fatty deposits on your artery walls.7
  • Within two to four years, there is a large drop in your risk of heart attack. Your risk then
    continues to gradually decrease.18
  • After fifteen years your risk of heart attack is close to that of a person who has never
    smoked.7

References

  1. Australian Institute of Health and Welfare. Australia's health 2006. AIHW cat. no. AUS 73. Canberra: AIHW; 2006.
  2. United States. Department of Health and Human Services. The health consequences of smoking: 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; 2004.
  3. National Stroke Foundation. What is a stroke? Available at: http://www.strokefoundation.com.au. Accessed 17 April, 2007.
  4. Australian Institute of Health and Welfare, Senes S. How we manage stroke in Australia. AIHW cat. no. CVD 31. Canberra: Australian Institute of Health and Welfare; 2006 February.
  5. Cadilhac DA, Carter R, Thrift A, et al. Investing in Stroke - What are the potential cost offsets from the strokesafe program? Technical report. Melbourne: National Stroke Research Institute; 2006.
  6. Australian Institute of Health and Welfare. Statistics on drug use in Australia 2006. Drug Statistic Series No. 18. Cat no. PHE 80. Canberra: AIHW; 2007.
  7. United States. Department of Health and Human Services. The health benefits of smoking cessation: a report of the Surgeon General Surgeon General's reports. Rockville. Maryland: United States, Public Health Service, Office on Smoking and Health; 1990.
  8. Thun MJ, Apicella LF, Henley SJ. Smoking vs other risk factors as the cause of smoking-attributable deaths: confounding in the courtroom. JAMA. 2000;284(6):706-12.
  9. English D, Holman CDAJ, Milne E, et al. The quantification of drug caused morbidity and mortality in Australia, 1995 edition : Part 2 Canberra: Commonwealth Department of Human Services and Health; 1995.
  10. Haemorrhagic stroke, overall stroke risk, and combined oral contraceptives: results of an international, multicentre, case-control study. WHO Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception. Lancet. 1996;348(9026):505-10.
  11. Farley TM, Meirik O, Chang CL, et al. Combined oral contraceptives, smoking, and cardiovascular risk. Journal of Epidemiology and Community Health. 1998;52(12):775-85.
  12. United States. Department of Health and Human Services. Reducing the health consequences of smoking : 25 years of progress : a report of the Surgeon General. DHHS publication ; no. (CDC) 89-8411. Rockville, Md.: U.S. Dept. of Health and Human Services Public Health Service Centers for Disease Control Center for Chronic Disease Prevention and Health Promotion Office of Smoking and Health; 1989.
  13. The Stroke Association (U.K.). What's the emergency? A report on the emergency response to stroke. Available at: http://www.stroke.org.uk/campaigns/current_campaigns/stroke_is_a_medical_emergency/campaign_report.html. Accessed 10th May, 2007.
  14. Wannamethee SG, Shaper AG, Whincup PH, et al. Smoking cessation and the risk of stroke in middle-aged men. JAMA. 1995;274(2):155-60.
  15. Godtfredsen NS, Holst C, Prescott E, et al. Smoking reduction, smoking cessation, and mortality: a 16-year follow-up of 19,732 men and women from The Copenhagen Centre for Prospective Population Studies. American Journal of Epidemiology. 2002;156(11):994-1001.
  16. Shopland DR, United States. Office on Smoking and Health., United States. Dept. of Health and Human Services., et al. The health consequences of smoking : cardiovascular disease : a report of the Surgeon General. Rockville, Md.: U.S. Dept. of Health and Human Services Public Health Service Office on Smoking and Health ; Washington D.C.; 1983.
  17. Moller AM, Villebro N, Pedersen T, et al. Effect of preoperative smoking intervention on postoperative complications: a randomised clinical trial. Lancet. 2002;359(9301):114-7.
  18. IARC. IARC Handbooks of cancer prevention, Tobacco Control, Vol. 11: Reversal of risk after quitting smoking. Lyon, France: International Agency for Research on Cancer; 2007.