A stroke occurs when a blood vessel bursts or is blocked and blood does not reach the brain. Without oxygen, brain cells quickly die, resulting in permanent disabilities to the part of the body controlled by the affected area of the brain. Smoking is a primary preventable risk factor for stroke.
Lipids and Triglycerides
According to the American Heart Association, smoking significantly increases triglycerides and low-density lipids, known as LDL, or bad cholesterol. LDL and triglycerides form fatty deposits, called plaque, on the walls of the arteries. A person with high levels of triglycerides or LDL risks developing atherosclerosis, a leading cause of stroke. Smoking also decreases high-density lipids, known as HDL, or good cholesterol. According to the American Heart Association, good cholesterol works to reduce risk of stroke as high-density lipids clean the plaque from artery walls and carry it back to the liver to be expelled from the body, decreasing a person's risk of developing atherosclerosis and resulting stroke.
Atherosclerosis
Atherosclerosis, often referred to as hardening of the arteries, develops when fat deposits stick to the artery walls and block flow of blood. Atherosclerosis can prevent blood from reaching the heart--resulting in heart attack--or the brain, resulting in stroke. According to the Merck Manuals Online Medical Library, atherosclerosis is the leading cause of illness and death in the United States and most developed countries. According to Merck, heart disease and stroke due to atherosclerosis cause more deaths than all other causes combined. Smoking is a primary modifiable risk for atherosclerosis.
Carbon Monoxide in the Blood
Cigarettes contain carbon monoxide, the same chemical released in car exhaust. When you breathe, oxygen attaches to hemoglobin in your blood, and the blood then carries the oxygen to the cells in your body, including brain cells. Carbon monoxide attaches more easily to hemoglobin, which produces carboxyhemoglobin, and its presence interferes with oxygen attachment. More carbon monoxide in your blood results in less oxygen reaching the cells in your body. As less oxygen reaches your brain, brain cells slowly die.
Oral Contraceptives and Smoking
On every package of oral contraceptives, you will likely find a warning that the combination of oral contraceptives and smoking increases risk of stroke. A meta-analysis published in the July 2000 issue of the Journal of the American Medical Association reviewed 16 studies conducted over the past 40 years. The authors determined that although the risk of stroke for women taking oral contraceptives was almost three times the risk for non-contraceptive users, the studies did not account for smoking's effect on risk. The authors concluded that when controlled for smoking, oral contraceptives alone present only a minor increase in stroke risk. Women who take oral contraceptives and smoke, however, significantly increase their risk of stroke.
Recovery from Stroke
Stroke causes permanent brain cell damage and often permanent disability to the area of the body associated with the damaged brain sector. An individual can
recover some function or limit further disability, however. A key component to recovery is cessation of smoking. By quitting smoking, a person can avoid additional disabling strokes and transmit fresh oxygen to other parts of the brain. The brain's plasticity provides it with the mechanisms necessary to adapt to injuries, such as stroke, but it requires oxygen to recover some of the damaged functions, motor skill and cognition lost as a result of the stroke.
References
- American Heart Association: Stroke
- American Heart Association: Good vs. Bad Cholesterol
- The Merck Manuals Online Medical Library: Atherosclerosis
- Discovery Health: How does smoking starve your heat of oxygen
- Guttmacher Institute: Despite Their Elevated Risk, Very Few Women Who Use Oral Contraceptives Will Experience an Ischemic Stroke
