Smoking reduces risk of Alzheimer's? Big Tobacco says yes.

Scientists have been researching connections between smoking and Alzheimer's disease for at least 20 years, yet dozens of studies appeared to come up with different results. The research team out of the University of California, San Francisco has a suggestion as to why that might be. "A lot of the classical studies were supported by the cigarette companies...We did a statistical analysis of all of the different studies done on Alzheimer's and found that the research funded by the tobacco industry tended to use inferior methods." Dr. Glantz said. "What we found was that [tobacco industry advisers] actually came up with a memo, that stated they were no longer going to use cohort studies, and it was because one of their paid consultants, P.N. Lee, looked into the situation and found that cohort studies were more likely to produce smoking as a risk factor."