Know the risks.

Health issues of smoking

The main health issues of smoking

Epidemiological studies have associated smoking with many different serious and fatal diseases. The diseases most studied have been lung cancer, chronic obstructive pulmonary disease and coronary heart disease.

Lung cancer

Statistical studies consistently report very strong associations between smoking and lung cancer, such that it is reasonable to conclude that smoking is an important cause of lung cancer. The statistics report higher incidence of lung cancer in groups that smoke for more years and smoke more cigarettes per day, with the length of time people have been smoking thought to be the most important factor. According to the Canadian Cancer Society smoking contributes to 80 percent of lung cancer deaths in women and 90 percent in men.  Men who smoke are 23 times more likely to develop lung cancer, while women are 13 times more likely, compared to people who have never smoked.  Studies show that after quitting, risks begin to decline and will vary according to a person’s smoking history. A former smoker’s level of risk in respect of the above diseases may approach that of a non-smoker after about 10 years or so of abstinence.

Chronic obstructive pulmonary disease (COPD)

COPD includes chronic bronchitis and emphysema. The statistical studies consistently report strong relationships between smoking and COPD that are of similar magnitude to the risks identified between smoking and lung cancer. As with lung cancer, the incidence is highest in groups that smoke for longer and smoke more cigarettes per day. Quitting is thought to slow the progression of the disease. Risks in groups of ex-smokers tend to remain higher than for never smokers, but lower than for those who continue to smoke.

Coronary heart disease (CHD)

Smoking is one of the causes of coronary heart disease. Heart disease is linked with many factors along with smoking; health authorities also regard high cholesterol, high blood pressure, obesity and lack of exercise as important. Some studies have reported that the risks for heart disease are greater in groups of people that have more than one of these risk factors (for example, smokers who get little exercise). The smoking-related risks of heart disease typically reduce after quitting.

Smoking during pregnancy

Public health authorities advise that pregnant women should not smoke, and have publicized this widely. Many statistical studies have reported a link between lower birth weight in babies and mothers who smoke throughout pregnancy. Some statistical studies have reported, amongst other factors, links between smoking in pregnancy and infant mortality, premature birth, miscarriage and stillbirth.

Other health issues

Epidemiological studies have reported various increased risks of other diseases among smokers. These include stroke (cerebrovascular disease), heart attack, aortic aneurysm, diseases affecting the circulation (such as peripheral vascular disease) and cancers of the throat, mouth, bladder, stomach and kidneys. The strength of the evidence linking these illnesses with smoking varies amongst the diseases and amongst different groups of people in different countries.