There are many good reasons not to smoke. You could get emphysema or cancer. You could catch cold standing with all the other smokers in front of your building in the winter time.
And, it turns out, you could be at a higher risk of developing dementia.
According to researchers writing in the current issue of Neurology, people who smoke are more likely to develop Alzheimers disease or dementia than nonsmokers or those who smoked in the past. Their study followed nearly 7,000 people age 55 and older for an average of seven years.
Over that time, 706 of the participants developed dementia. People who were current smokers at the time of the study were 50 percent more likely to develop dementia than people who had never smoked or past smokers.
Smoking could affect the risk of dementia through several mechanisms, according to study author Monique Breteler, MD, PhD, of Erasmus Medical Center in Rotterdam, the Netherlands, and member of the American Academy of Neurology.
Smoking increases the risk of cerebrovascular disease, which is also tied to dementia, Breteler said. 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 Alzheimers disease.
Oxidative stress occurs when the body has too many free radicals, which are waste products produced by chemical reactions in the body.
Antioxidants in the diet can eliminate free radicals, and studies have shown that smokers have fewer antioxidants in their diets than nonsmokers, Breteler said.
The researchers also looked into how smoking affects the risk of developing Alzheimers disease for people who have the gene that increases the risk of Alzheimers, called apolipoprotein E4, or APOE-4.
They found that smoking did not increase the risk of Alzheimers for those with the APOE-4 gene. But for those without the APOE-4 gene, smoking increased the risk of Alzheimers. Current smokers without the Alzheimers gene were nearly 70 percent more likely to develop Alzheimers than nonsmokers or past smokers without the Alzheimers gene.
The study was supported by Erasmus Medical Center and several governmental health organizations in the Netherlands.
