Male smokers lose brain function faster as they age

Men who smoke suffer a more rapid decline in brain function as they age than their non-smoking counterparts, with their cognitive decline as rapid as someone 10 years older but who shuns tobacco, scientists said on Monday.

In a large, long-term study, British researchers found that while there seems to be no link between cognitive decline and smoking in women, in men, the habit is linked to swifter decline, with early dementia-like cognitive difficulties showing up as early as the age of 45.

The research adds to an already large body of evidence about the long-term dangers of smoking - a habit the World Health Organisation refers to as "one of the biggest public health threats the world has ever faced."

Smoking causes lung cancer, which is often fatal, and other chronic respiratory diseases. It is also a major risk factor for cardiovascular diseases, the world's number one killers.

"While we were aware that smoking is a risk factor for respiratory disease, cancer, and cardiovascular disease, this study shows it also has a detrimental effect on cognitive ageing and this is evident as early as 45 years," said Severine Sabia of University College London, who led the study and published it in the Archives of General Psychiatry journal.

A male regular smoker has a higher risk of rapid cognitive decline, compared to his counterparts who do not smoke, researchers from University College London, England, reported in Archives of General Psychiatry. The authors add that the evidence has been mounting regarding the link between smoking and dementia in elderly individuals - smoking has been found to push up the total number of patients with dementia around the world.

Séverine Sabia, Ph.D., and team set out to determine what impact smoking might have on men during their transition from middle age to old age. They gathered data from the Whitehall II cohort study, which was based on people who worked in the British Civil Service. They analyzed data on 2,137 females and 5,099 males whose average age at their first cognitive assessment was 56 years.

They specifically looked at six assessments of individuals' smoking status over a 25-year-period, as well as three cognitive assessments which took place over a decade.

In an interview she said one explanation for the gender difference found in this study might be the larger amount of tobacco smoked by men, or the fact that there was a significantly lower proportion of women than men among those involved in the research.

Sabia's team looked for possible links between smoking history and cognitive decline in the transition from midlife to old age using data from 5,099 men and 2,137 women who are involved in a large research project called the Whitehall II study, which is based on employees of the British Civil Service.

The researchers found that: