However, some people who have early-onset Alzheimer's don't have mutations in these three genes. That suggests that this early-onset form of Alzheimer's disease is linked to other genetic mutations that haven't been identified yet.
Early history Cigars, cigarettes Cancer by the carton Legal history Surgeon General's warning. (CNN) -- Tobacco was first used by the peoples of the pre-Columbian Americas. Native Americans apparently cultivated the plant and smoked it in pipes for medicinal and ceremonial purposes.
Tobacco was introduced to France in 1556, Portugal in 1558, and Spain in 1559, and England in 1565. The first successful commercial crop was cultivated in Virginia in 1612 by Englishman John Rolfe. Within seven years, it was the colony's largest export. Over the next two centuries, the growth of tobacco as a cash crop fueled the demand in North America for slave labor. At first, tobacco was produced mainly for pipe-smoking, chewing, and snuff. Cigars didn't become popular until the early 1800s. Cigarettes, which had been around in crude form since the early 1600s, didn't become widely popular in the United States until after the Civil War, with the spread of Bright tobacco, a uniquely cured yellow leaf grown in Virginia and North Carolina.