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Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
People with high total cholesterol have about two times the risk for heart disease as people with ideal levels.
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.
Asthma cases in Americans are about 75% higher today than they were in 1980.
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.