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.
There is little reliable information concerning the early uses of tobacco by Native Americans prior to the arrival of Europeans in 1492. Some Mayan and Incan drawings and carvings appear to show tobacco in use in ceremonies but little is known of the actual meaning of those representations.