On Nov 10, the U.S. Food and Drug Administration announced a proposal to use nine new larger and more noticeable textual warning statements and color graphic images to warn consumers about cigarette smoking or tobacco use in cigarette packages and advertisements in the hopes that more people will be scared away from smoking.

Cigarette smoking has been linked with many diseases of which some are fatal.  Many studies suggested that tobacco smoking boosts Alzheimer's disease for which there is no cure and patients with the disease become completely disabled eventually.

A review study recently reported in Journal of Alzheimer's disease suggests cigarette may increase risk of Alzheimer's disease.

The review study led Janine Cataldo and colleagues at the University of California - San Francisco found case control studies with tobacco industry affiliation tended to suggest that smoking protects against Alzheimer's disease while studies without tobacco industry involved found the effect was not significant.

The researchers meta-analyzed data from 43 qualified individual studies, of which one fourth had tobacco industry affiliated authors, on the association between cigarette or tobacco use and Alzheimer's disease to see if the industry may introduce biases into the studies.

Data from 18 cases-control studies without tobacco industry involved suggested that cigarette smoking was associated with 9 percent reduced risk of Alzheimer's disease, but the reduction was not statistically significant.

In comparison, data from 8 case-control studies with tobacco industry affiliation showed that cigarette smoking was linked with 14 percent reduced risk of Alzheimer's disease.

Cohort studies yielded a similar discrepancy.  A total of 14 cohort studies without the industry involved together showed cigarette smoking was correlated with 45 percent increased risk of Alzheimer's disease while 3 studies with industry authors involved showed the increase in the risk was non-significant.

The researchers analyzed data using multiple regression methods showed that compared to cohort studies, case-control studies without industry authors involved resulted in 27 percent lower estimates of the effect of cigarette smoking on Alzheimer's disease.  With industry authors involved, the estimate from case-control studies was 37 percent lower. 

Studies published in 2007 without tobacco industry affiliation estimated that cigarette smoking was linked with 72 percent increased risk of Alzheimer's.

The researchers concluded that "The available data indicate that smoking is a significant risk factor for Alzheimer's Disease."

Jimmy Downs