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. One research team discovers some not so surprising results. MDiTV: It's g...
Read the full transcript »

You may have heard that smoking is good for you. Let me repeat that. You may have heard that smoking is good for you. Or to be more specific that people who smoke might be less likely to develop Alzheimer’s disease. The idea was that perhaps nicotine had some beneficial effect on brain function. Although clearly, smoking causes blood vessel disease and other problems that raise the risk of dementia. Still, researches wondered why some but not all studies suggested smokers don’t develop Alzheimer’s disease as often as non-smokers. Of course, researchers hadn’t randomized people to either smoke or not, they simply observed smokers and non-smokers and tracked rates of Alzheimer’s, or they compared smoking histories of people who have Alzheimer’s with those who don’t. But this sort of observational study always leave some questions. Maybe there was something else going on. Something that the study authors didn’t measure or report on that was the real answer. Janine Cataldo at the University of California San Francisco and her colleagues decided to take a closer look at previous research. Janine Cataldo: There were these prevailing beliefs smoking had a protective factor against Alzheimer’s. And they say that they hit on something that appeared to make a difference. Whether or not research s involved in those smoking and Alzheimer’s had ties to the tobacco industry. Janine Cataldo: Instead of just looking at tobacco industry funding or sponsorship, we broadened the definition and we looked at and defined affiliation as current or past funding, somebody who is employed by the tobacco industry or was a paid consultant, someone who collaborated or shared data, co-author sheet on the included study with someone with current funding or previous tobacco industry funding and our cut off was for ten years. The studies with tobacco industry ties pointed to a lower risk of Alzheimer’s among smokers. But when these researchers tossed out those results, co-author Stanton Glantz says, the remaining study is the ones without a whiff of tobacco industry connections. Well, they produced a very different picture. Dr. Stanton Glantz: Smoking increases the risk of Alzheimer’s disease by almost a factor of two. So contrary to the widely held view that smoking actually protects people from Alzheimer’s that actually increases the risk of Alzheimer’s The UC San Francisco researchers also found documentation that at least some tobacco industry advisers were suggesting ways to avoid doing studies that might produce unfavorable results. Dr. Janine Cataldo: And what we found was that they actually came up with a memo that stated that they were no longer going to use cohort studies and it was because one of their paid consultants, PN Lee, looked into the situation and found that cohort studies were more likely to produce smoking as a risk factor. An Alzheimer’s Association representative said that the findings of this reanalysis of the research makes sense. Judy McKellar: My approach to it all is common sense, and I know that common has the same goals that are really common. But if we drink to excess, it’s going to hard on our body. If we smoke, it’s going to be hard on our body. Science has proven that. So thinking that smoking cigarettes will help our brain function better seems to me that it doesn’t fall into the area of common sense no matter what the prevalent attitude is. It appears that exposing and factoring out tobacco industry influence clears the air and shows that when it comes to Alzheimer’s, there’s no silver lining to the clouds of tobacco smoke.

Advertisement
Advertisement
Advertisement