Heavy smoking during middle age can double the risk of Alzheimer's disease and dementia two decades later, researchers said on Monday.
Smoking already causes millions of deaths each year from cancer and heart disease.
"Our study suggests that heavy smoking in middle age increases the risk of both Alzheimer's disease and vascular dementia for men and women across different race groups," Rachel Whitmer, a research scientist with Kaiser Permanente in Oakland, California and colleagues wrote in the Archives of Internal Medicine.
They said smoking also causes cancer and heart disease. The new findings show it threatens public health in late life, when people are already more likely to develop dementia.
Whitmer's team analyzed data from 21,123 members of a health plan who took part in a survey when they were in their 50s and 60s.
About 25 percent of the group, 5,367 volunteers, were diagnosed with some form of dementia in the more than 20 years of follow up, including 1,136 people who were diagnosed with Alzheimer's disease.
http://www.msnbc.msn.com/id/39837972/ns/health-addictions/
