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.
Two main types of tobacco are involved in early history. In general, tobacco from Mexico North was a different variety than that grown in the Caribbean and South America. The tobacco used by North American natives that the English first smoked was a somewhat dreadful variety nicknamed âshoestringâ by colonists.