Alzheimer's and smoking linked by Dutch study

William Atkins
Wednesday, 12 September 2007 18:46

Science - Health

Dutch scientists found that people who smoked were 50% more likely to suffer Alzheimer’s disease or dementia that nonsmokers or smokers who had quit.                       

In the study, almost 7,000 people 55 years old or older were studied over an average of seven years. Of those people, 706 eventually developed dementia, which is a condition that causes a decrease in the functioning of a person’s cognitive abilities such as memory, attention, and problem solving. Alzheimer’s disease is a neurodegenerative disease that is a major type of dementia, primarily affecting people over the age of 65 years.

The author of the study, Dutch researcher Monique Breteler, published the result, along with fellow colleagues, in the September 4, 2007 issue of the journal Neurology. Professor Breteler is associated with the Department of Epidemiology and Biostatistics, Erasmus Medical Center, in Rotterdam, the Netherlands.

She found that smokers were 50% more likely to develop cerebrovascular disease, which is associated with dementia and Alzheimer’s disease, than nonsmokers or previous smokers who had quit. For people who had the gene (apolipoprotein E4, or APOEa4) that increases the risk of Alzheimer’s, smoking did not change the risk of developing Alzheimer’s. However, smokers who did not have the APOEa4 gene were 70% more likely to develop Alzheimer’s than nonsmokers.

Breteler explain the reason: "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 is a process caused by an excess of free radicals in the body. Free radicals are waste products that are produced by chemical reactions within the body. Free radicals attack the body’s proteins, fats, and carbohydrates and, thus, can cause serious damage. The damage caused by free radicals is done by a chemical reaction called oxidation. When free radicals attack healthy atoms, molecules, or tissues of the body, the degrading process of oxidative stress occurs by damaging a person’s DNA. Deoxyribonucleic acid, or DNA, is a nucleic acid that contains the genetic information used for all development and functions within all living things.

Breteler goes on to say, "antioxidants in the diet can eliminate free radicals, and studies have shown that smokers have fewer antioxidants in their diets than nonsmokers."