Smoking Linked To Cognitive Decline
November 28, 2012

Researchers Find Smoking, Other Factors Linked To Cognitive Decline In People Over 50

Lawrence LeBlond for - Your Universe Online

There´s an overwhelming body of evidence that smoking contributes to cancer, lung disease, heart disease, low birth weight and other health issues. Now, new research from King´s College London is showing that picking up that cigarette is also associated with mental decline such as forgetfulness and slower thinking. And for those over 50, smoking can lead to accelerated decline in brain function.

Published today in the journal Age and Ageing, the study of 8,800 people over the age of 50 found that those who smoked performed more poorly on a range of cognitive tasks designed to test memory recall, verbal fluency, attention and other cognitive functions than those who never picked up the habit.

The study also showed, although to a lesser extent, that high blood pressure and being overweight also led to poorer brain function.

The researchers said those who smoke consistently were found to have a decline in mental function and ability in tests over four years, with many finding difficulty in remembering certain common words. Others had difficulty organizing daily tasks, or showed signs of becoming more forgetful. The same patients were tested again after another four years and were found to have accelerated mental decline due to smoking.

The study authors said future trials should focus on combinations of risk factors rather than individual cases of mental decline, being that study results showed that besides smoking and being overweight, heart attack and stroke were also “significantly associated with cognitive decline,” with those at the highest risk showing the greatest decline.

This was one of the few longitudinal investigations to explore the combined effect of multiple risk factors on cognitive decline in older adults. The researchers analyzed data on smoking, blood pressure, cholesterol levels and body mass index (BMI), as well as Framingham cardiovascular and stroke risk scores (used to determine probability of an individual developing heart disease or stroke within ten years).

“Cognitive decline becomes more common with ageing and for an increasing number of people interferes with daily functioning and well-being,” said study coauthor Dr. Alex Dregan of KCL. “We have identified a number of risk factors which could be associated with accelerated cognitive decline, all of which, could be modifiable.”

“We need to make people aware of the need to do some lifestyle changes because of the risk of cognitive decline,” he added.

At the four and eight-year follow-ups, participants underwent cognitive testing on performance, memory and functioning, which were combined into a third, overall “cognitive index” score. The memory tests included learning ten unrelated words before immediate and delayed recall was tested. For the assessment of executive functioning, participants were asked to name as many animals as possible in one minute, which examined verbal fluency, and to cross-through specified letters in a series, which measured attention, mental speed and visual scanning.

Through the testing, the researchers found that smoking had the most consistent impact, linked with lower performance in all three areas of the test after four years.

“We all know smoking, a high blood pressure, high cholesterol levels and a high BMI (body mass index) is bad for our heart,” Jessica Smith, from the Alzheimer's Society, told the Telegraph´s Hannah Furness. “This research adds to the huge amount of evidence that also suggests they can be bad for our head too.”

“One in three people over 65 will develop dementia but there are things people can do to reduce their risk,” Smith added. “Eating a balanced diet, maintaining a healthy weight, exercising regularly, getting your blood pressure and cholesterol checked and not smoking can all make a difference.”

Dr. Simon Ridley, from Alzheimer´s Research UK, said: “Cognitive decline as we age can develop into dementia, and unraveling the factors that are linked to this decline could be crucial for finding ways to prevent the condition“¦These results underline the importance of looking after your cardiovascular health from mid-life.”

“Our research suggests that the most promising approach to delaying or preventing early ageing of the brain is one that acknowledges the multi-causality of cognitive decline. Thus, current efforts to reduce cardiovascular risk may prove beneficial for cognitive decline,” noted Dregan in a statement.

“One such initiative is the NHS Health Check programme, aimed at preventing cardiovascular disease by inviting 40-74 years olds to five-yearly check-ups in order to assess their risk of developing stroke, diabetes, kidney disease or heart disease, and to offer advice and support to help them manage that risk,” Dregan concluded.