Cigarette smoking is a major risk factor in heart disease, stroke and lung cancer. Every year 30,000 Canadians die from the effects of smoking. Emphysema, a condition in which the lungs are abnormally enlarged, is a life-threatening disease that is often associated with smoking. Chronic bronchitis and cancer of the larynx, mouth, bladder, kidney and pancreas occur in many people who have smoked heavily for years. Babies of smoking mothers often have low birth weight, are shorter in length, and have small head circumference.
Some studies link smoking with miscarriage and stillbirths.
Some research also suggests that smoking when pregnant can lead to the child having learning and behaviour problems. Sidestream or secondhand smoke that is not directly inhaled by the smoker can harm people who are exposed to it. Tolerance and Dependence Tolerance is the body adapting to the presence of a drug. When tolerance to a drug increases, more of the drug is necessary to achieve the same effect. Smokers develop tolerance to the effects of tobacco.