Two-Pack-A-Day Smokers at Double the Risk for Dementia
What is bad for the heart and lungs is also bad for the brain. People who are heavy smokers are at more than double the risk of developing Alzheimer’s disease and other forms of dementia, finds a study from researchers at the University of Eastern Finland.
Regular Smoking Contributes to Inflammation, Vascular Injury, and Neurodegenerative Disease
Lead researcher Rachel A. Whitmer, a research scientist in Kaiser Permanente's Division of Research in Oakland CA, and team analyzed data from over 21,000 participants who took part in a survey between 1978 and 1985 when they were between the ages of 50 and 60. Diagnoses of Alzheimer’s and other dementias were tracked between 1994 and 2008.
An average of 23 years after the initial survey, 25.4% of the participants were diagnosed with dementia. People who smoked more than two packs of cigarettes a day had greater than a 100% increase in the risk of developing dementia over nonsmokers, former smokers, and those who smoked less than a half a pack per day. The association did not change after adjusting for race, gender, or comorbid conditions such as high blood pressure, high cholesterol, or weight.
Smoking contributes to dementia risk in several ways. First, smoking causes oxidative stress and inflammation, known to play a role in the development of Alzheimer’s disease. Second, smoking causes damage to the arteries in the brain, a risk factor for vascular dementia, the second most common form of dementia after Alzheimer’s. Prior studies have linked regular smoking to an increased risk of neurodegenerative conditions, such as Parkinson’s disease.
The researchers are planning a follow-up study to find out if less intense smoking habits or quitting smoking is protective against the development of dementias.
Rusanen M, et al "Heavy smoking in midlife and long-term risk of Alzheimer disease and vascular dementia" Arch Intern Med 2010; DOI:10.1001/archinternmed.2010.393.