Smoking more than doubles the risk of Alzheimer’s and vascular dementia.
A Kaiser Permanente studyæreported that an analysis of more than 20,000 men and women, studied since 1978, found a 157 percent heightened risk of Alzheimer’sæfor people who smoked two packs or more a day. For vascular dementia, which is the second most common dementia, there was a 172 percent risk increase. For smokers who smoke less than two packs a day, the risk is less than their heavier smoking counterparts, but much greater than non-smokers. Half a pack to one pack a day smokers had a 37 percent greater chance of dementia, while one to two pack a day smokers had a 44 percent increase.
Some believe the numbers may still be an underestimation. Kenneth Hepburn, an associate dean for research at the Emory University School of Nursing, told CNN that many smokers may die before they develop dementia, and therefore not show up in data collected.
Researchers are unsure of why the association between smoking and dementia is so strong. Rachel Whitmer, the study’s co-author said that smoking may play a role in the damage of blood vessels, as well as brain cells.
The people studied were all middle-aged at the time the research. None smoked less than a half pack a day. So far, there is no evidence to support smoking less than a half pack a day, or smoking while young but then stopping before mid-life, increases dementia risk compared to non-smokers.