Smoking and cardiovascular disease

Risk factors for CHD

Cigarette smoking, raised blood cholesterol and high blood pressure are the most firmly established, non-hereditary risk factors leading to CHD, with cigarette smoking being the "most important of the known modifiable risk factors for CHD", according to the US Surgeon General.¹ Coronary heart disease is the leading cause of death in the United States, with cigarette smokers being 2-4 times more likely to develop coronary heart disease than nonsmokers.²

The role of smoking in Cardiovascular Disease

Tobacco smoke can quickly affect the heart and blood vessels, causing heart rate to rise almost immediately. The carbon monoxide in tobacco smoke also reduces the blood's ability to carry oxygen.

Smoking tends to increase blood cholesterol levels. The ratio of high-density lipoprotein cholesterol (the "good" cholesterol) to low-density lipoprotein cholesterol (the "bad" cholesterol) tends to be lower in smokers compared to non-smokers. Smoking also raises the levels of fibrinogen (a protein which causes blood to clot) and increases platelet production (also involved in the formation of blood clots) which makes the blood stickier. Because the blood is stickier, carbon monoxide attaches itself to hemoglobin (the oxygen-carrying pigment in red blood cells) much more easily than oxygen does. This reduces the amount of oxygen available to the tissues. All these factors make smokers more at risk of developing various forms of heart disease.

Aneurysm

An aneurysm is a balloon-like bulge in the wall of an artery which can eventually burst. A study looking at over 5,000 men and women aged 65-79 years found that smoking was the most important avoidable risk factor for abdominal aortic aneurysm.³

Peripheral vascular disease (PVD)

Peripheral artery disease is a condition of the blood vessels that leads to narrowing and hardening of the arteries that supply the legs and feet. Smoking tightens arteries, decreases the blood's ability to carry oxygen, and increases the risk of forming clots. Smokers have a 16 times greater risk of developing peripheral vascular disease (blocked blood vessels in the legs or feet) than people who have never smoked.⁴

Stroke

Smokers are more likely to develop stroke than non-smokers. A stroke is an interruption of the blood supply to any part of the brain. Cigarette smoking approximately doubles a person's risk for stroke.⁵ Even secondhand smoke can substantially increase one's chances of having stroke, based on a study of nonsmoking spouses married to a smoker.⁶

The benefits of stopping smoking

Your body will begin to heal itself almost immediately after your last cigarette! Within 20 minutes your heart rate and blood pressure drop, within 12 hours the carbon monoxide level in your blood drops, and within just a few weeks your circulation begins to improve and lung function increases.

Long term effects of quitting include the following

• 1 year: risk of coronary heart disease becomes half that of a smoker's.
• 5 years: Stroke risk is reduced to that of a non-smoker within 5 to 15 years after quitting
• 10 years: Lung cancer death rate is about half that of a smoker's.
• 15 years: Coronary heart disease risk is the same a non-smoker's.⁷

Secondhand smoke

Exposure to secondhand tobacco smoke can cause heart disease in non-smokers. One recent study indicated that secondhand smoke can increase the risk of coronary heart disease by 50% to 60%.⁸