Smokers More Likely to Develop Alzheimer's Disease and Dementia

In a recent press release, the American Academy of Neurology (AAN) announced a study that's published in their Sept. 4 issue of "Neurology" showing that people who smoke are more likely to develop Alzheimer's disease or dementia than nonsmokers or those who were former smokers.

The study, supported by Erasmus Medical Center and several governmental health organizations in the Netherlands, followed approximately 7,000 people age 55 and older for an average of seven years. During that time, 706 of the participants developed dementia. People who were smokers at the start and throughout the study were 50 percent more likely to develop dementia than people who had either never smoked or who had quit at some point prior to the start of the study. This follows the conclusions of a 2006 analysis of some 19 similar studies.

In March 2007, the American Journal of Epidemiology published the results of the 2006 analysis of 19 different studies of smokers and non-smokers and incidents of Alzheimer's disease. The analysis was authored by Drs. Kaarin J. Anstey, Chwee von Sanden, Agus Salim and Richard O'Kearney. They assessed the association of smoking with dementiaand cognitive decline as found in 19 studies involving 26,374 participants who were followed for dementia for 2 to 30 years, and 17,023 participants who were followed for 2 to 7 years. The mean age of the participants was 74 years. When all was said and done, the authors concluded that elderlysmokers clearly have increased risks of dementia and cognitive decline.

Dr. Monique Breteler, of Erasmus Medical Center and a member of the AAN, is the author of the study published in "Neurology." She said that "smoking increases the risk of cerebrovascular disease, which is also tied to dementia. Another mechanism could be through oxidative stress, which can damage cells in the blood vessels and lead to hardening of the arteries. Smokers experience greater oxidative stress than nonsmokers, and increased oxidative stress is also seen in Alzheimer's disease."

Oxidative stress happens when the body has too many free radicals (waste products produced by chemical reactions in the body). Dr. Breteler said that "antioxidants in the diet can eliminate free radicals, and studies have shown that smokers have fewer antioxidants in their diets than nonsmokers."

On Sept. 4, Dorian Martin posted on OurAlzheimer's.com her experiences in caring for her mother who was not only a heavy smoker, but was diagnosed in 2005 with Alzheimer's disease. Martin says her mother smoked her first cigarette at age 16, smoked "like a chimney" for more than 50 years - until age 74 - and quit in the late 1990s when diagnosed with COPD. In the meantime, she is said to have smoked as much as two packs of cigarettes a day "during her smoking prime." Martin says that "not only did Mom wreck her lungs, but she might have unwittingly contributed to the development of Alzheimer's disease."

When discussing with her father the new study just published in "Neurology," Martin's father talked about how Martin's mother "rationalized the quantity she smoked daily by noting that most of the cigarettes burned off in the ashtray." When encouraged to quit, she would remind them the brand she smoked was low in tar.

According to Martin, as her mother's lungs got worse, her "short-term memory problems were becoming evident. In 2005, she was diagnosed with Alzheimer's." Martin went on to say that after their mother's diagnosis, Martin and her brother "came to the same hypothesis, separately - we believe that Mom smoked like crazy so that she would avoid getting dementia. Having been the caregiver for her mother who had dementia, Mom was adamant: 'If I get like that, just take me out to the desert and let me walk away!' It's sad to think that Mom's plan to shorten her life so she wouldn't get dementia might have contributed to her getting the disease she most feared."

Sources:

Press release, Smokers Are More Likely to Develop Dementia; http://www.newswise.com/articles/view/532855/

American Journal of Epidemiology, Smoking as a Risk Factor for Dementia and Cognitive Decline: A Meta-Analysis of Prospective Studies; http://aje.oxfordjournals.org/cgi/content/abstract/166/4/367

OurAlzheimer's.com, Smokers More Likely to Get Dementia, Alzheimer's; http://www.healthcentral.com/alzheimers/c/42/12993/smokers-disease/