Reverse Aging & Mental Health | Jon Barron's Blog

The Smoking-Dementia Connection

Cigarettes, Smoking, Dementia, Alzheimer's

“The public health authorities never mention the main reason many Americans have for smoking heavily, which is that smoking is a fairly sure, fairly honorable form of suicide.”  ~ Kurt Vonnegut

As if there is not enough proof already that smoking is bad for you, new research has established a link between smoking and the development of dementia in later years. Compared to nonsmokers, those who smoke two packs of cigarettes a day during middle age face a 157% increased chance of developing Alzheimer’s disease and a 172% greater risk of developing vascular dementia.

The study, executed jointly by researchers at Kaiser Permanente in Oakland, California, and at the University of Eastern Finland in Kuopio, analyzed the histories of 21,123 middle-aged men and women and followed up with them for more than 20 years. Most were at least 50 years old when the surveys commenced between 1978 and 1985. The subsequent tracking took place when the participants were an average of 71.6 years old, from 1994 through 2008.

The sample size of the study was large enough to prove that the effects of smoking on causing dementia are the same across the board despite gender or ethnicity. Those subjects who smoked earlier in their lives and quit or smoked less than half a pack a day did not seem to have an increased risk factor for developing dementia.

Two decades from the start of the research, 25% of the volunteers — 5,367 people — were diagnosed with dementia. Nearly a quarter of this group (1,136 people) were found to have Alzheimer’s disease. The most common form of dementia, Alzheimer’s typically strikes those 65 and older and is the cause of 50 to 70% of dementia cases. A possible reason that smoking may precipitate dementia has to do with increased inflammation caused by smoking. Previous research has suggested links between inflammation of neuropathways in the brain and Alzheimer’s disease.

Vascular dementia, a cognitive impairment defined by damage to, or blockages of, the blood vessels in the brain, is the second most common form of the disease. In the study, it was responsible for several hundred more of the diagnoses. Since smoking is a major risk factor for stroke, it’s possible that smoking contributes to vascular dementia in the same way by narrowing blood vessels and depriving brain cells of oxygen.

This is the first study to focus on the long-term consequences of smoking in relation to dementia, but not the first to establish links between them. Research at the University of California, San Francisco that took place earlier this year found that smoking is a substantial risk factor for the disease. The researchers reviewed 43 studies that were published between 1984 and 2007 and discovered, amazingly, that those studies affiliated in some way with the tobacco industry suggested that smoking can protect you from Alzheimer’s disease. Protect?!?

Much less surprisingly, all of the independent studies they examined (i.e., those with no tobacco industry ties) showed the exact opposite findings over and over again — that smoking does indeed increase your risk of developing Alzheimer’s disease. Approximately one-quarter of the studies were tobacco-industry related and the other three-quarters were independent.

We already know that nearly 9 million Americans have chronic ailments such as emphysema, heart disease, and chronic bronchitis that are all smoking-related. Smoking is responsible for 87% of lung cancer fatalities as well as 30% of total cancer deaths. In addition, 5.3 million Americans have been stricken with Alzheimer’s disease and that number will be swiftly rising as the baby boomers become senior citizens. It is expected that the number of people diagnosed will be three times its current tally by the year 2050. And, according to the Alzheimer’s Association, dementia triples health care costs for those it afflicts.

All of this should be particularly disturbing in China, considering that 75% of all adult males over age 30 currently smoke heavily in that country. The medical costs associated with the millions and millions of inevitable Alzheimer cases on the horizon, will be back breaking. And worldwide, we’re talking about over a billion smokers. Truly, we have seen only the tip of the Alzheimer’s iceberg headed our way.