Risk of developing Alzheimer's disease and vascular dementia is up to 80 percent higher among elderly smokers compared to people the same age who don't smoke, Australian researchers report.

The Australian National University researchers analyzed 19 studies on smoking among older adults (mean age: 74) to reach their conclusions. They found that while current smokers had a much higher risk of dementia, the same was not true of former smokers, although ex-smokers did have an increased risk of cognitive decline compared to those who never smoked.

"When compared with people who have never smoked, current smokers have an increased risk of dementia and cognitive decline ranging from 40 percent to 80 percent, depending on the type of dementia or cognitive outcome examined," said Anstey. "Based on this research, public-health information should be updated for smokers to include a warning that smoking may increase the risk of dementia."

The research, led by Kaarin Anstey of the school's Center for Mental Health Research, was published in the June 14, 2007 issue of the American Journal of Epidemiology.