Large Scale Study Suggests Passive Smoking Link to Dementia

Researchers have published the results of the first large-scale study to indicate that second-hand smoke exposure could lead to dementia and other neurological problems.

Research has already identified possible links between active smoking and cognitive impairment, and previous findings have suggested exposure to second-hand smoke is linked to poor cognitive performance in children and adolescents.

However, this is the first study of its kind to link second-hand smoke exposure to cognitive impairment in adult non-smokers.
The research team examined saliva samples from almost 5000 non-smoking adults over the age of 50, using data from the 1998, 1999 and 2001 waves of the Health Survey and England. The participants subsequently took part in the English Longitudinal Study of Ageing.

The saliva samples were tested for cotinine, a product of nicotine that remains in the saliva for about 25 hours after exposure to second-hand smoke. Those who took part in the study also provided a detailed smoking history, and those who had never smoked, or who were previous smokers, were assessed separately.

Established neuropsychological tests were used to assess brain function and cognitive impairment. These focused on memory function, numeracy and verbal fluency. The test results were added together to provide a global score for cognitive function. Those whose scores were in the lowest 10 per cent were identified as suffering from cognitive impairment.

The researchers believe that the link between second-hand smoke and cognitive impairment could be explained by the fact that heart disease increases the risk of developing dementia, and that exposure to second-hand smoke is known to cause heart disease.

Dr. Iain Lang from the Peninsula Medical School, who worked on the study, commented: "This is the first time that anyone has used biological measures of exposure to second-hand smoke to show that passive smoking is bad for the human brain. While the ban on smoking in public places has gone some way to mitigate this problem, there is still a risk from smoking at home. We hope that our findings will encourage smokers to change their behavior in order to reduce the risk to others."

He added, "These findings are of enormous public health importance for two reasons. First, a lot of people smoke cigarettes and it's important that they are fully aware of the harm they do to themselves, and others, by smoking. Second, the rapidly growing numbers of older people in the population, and the escalating cost of caring for people with dementia and related problems, mean that it's crucial to identify and take action on factors that can reduce the risk of developing cognitive problems. Encouraging people to quit smoking, or not to take it up in the first place, may be one way to achieve this."

Related Articles

Dietary Patterns Associated With Reduced Alzheimer's Disease Risk

Individuals whose diet includes more salad dressing, nuts, fish, poultry and certain fruits and vegetables and fewer high-fat dairy products, red meats, organ meats and butter appear less likely

Alzheimer's Brain Changes Observed in Older Persons Without Dementia

Researchers have uncovered an early disruption in the process of memory formation in older humans who exhibit some early brain changes associated with Alzheimer's

Computer Program Developed for Early Diagnosis of Alzheimer's Disease

Researchers of the University of Granada have developed a new computer program that allows early diagnosis of Alzheimer's disease through processed images. This new system has enhanced

The Effects of Fish Oil, Caffeine and Copper in Alzheimer’s

Alzheimer's currently afflicts an estimated 5.1 million Americans. By 2050, the number of individuals age 65 and over with Alzheimer's could range from 11 million

Study Indicates Alzheimer's Disease Begins Quietly and Undetected

The emergence of multiple new brain imaging technologies and the combined application of these new approaches is helping to create new insights into aging and

References:
1. Iain Lang , et al. The Peninsula College of Medicine and Dentistry.
2. Image by Nufkin.