ATHEROSCLEROSIS  
 

Arteriosclerosis or "hardening of the arteries," is a disorder characterised by a progressive thickening and hardening of the walls of the arteries, causing a decrease in or loss of blood circulation. Some hardening of arteries normally occurs when people grow older. The most common form of arteriosclerosis is atherosclerosis, which is characterised by the deposition of fatty substances in large and medium-sized arteries such as those serving the heart and brain.
Heart and brain diseases are often the direct result of this accumulation of substances that impair the arteries' ability to nourish vital body organs. Atherosclerosis and its complications are the major cause of death in Canada (40% of adult deaths).

 
  WHAT IS ATHEROSCLEROSIS?  
 

Atherosclerosis comes from the Greek words athero (meaning gruel or paste) and sclerosis (hardness). It involves deposits of fatty substances, cholesterol, cellular waste products, calcium and other substances in the inner lining of an artery. This build-up is called plaque or atheroma. The type of artery involved and the location of the plaque varies with each person, but the most common sites tend to be the aorta, the coronary vessels to the heart, the carotids in the neck and the arteries in the legs. Plaque may partially or totally block the blood's flow through an artery. Wherever there is plaque, two things can occur:

 
 
1. Bleeding (haemorrhage) into the plaque.  
2. The plaque ruptures and a blood clot (thrombus) forms on the plaque's surface.  
 
  If either of these occurs, complete blockage is more likely to result.  
  Atherosclerosis increases as one ages, but some people do not develop it.  
  It is a slow, progressive disease that may start to develop as early as childhood, particularly in cases of hereditary or familial hypercholesterolaemia. In some people this disease progresses rapidly in their third decade, while in others it does not become threatening until they are in their fifties or sixties.  
  CAUSES AND RISK FACTORS  
  The exact cause of atherosclerosis is not known, but there are several risk factors and associations. People's susceptibility to atherosclerosis varies with their genetic make-up and their lifestyles.  
  Some of the factors which increase the likelihood of atherosclerosis are:  
  Hypertension (high blood pressure); cigarette smoking; diabetes; obesity; and elevated levels of cholesterol and other fatty substances in the blood. Other factors that probably influence atherosclerosis include physical inactivity and a family predisposition. It is particularly common in whites and Asians, and is 6 times more common in men than pre-menopausal women (ages 35-45 years). After menopause the rates in women approach the rates in men.