Smoking and excess weight shrinks the brain

The effects may lead to impaired thinking up to a decade later, say US scientists.

Smoking and high blood pressure also led to increases in "white matter hyperintensities", small lesions or areas of brain damage.

"Our findings provide evidence that identifying these risk factors early in people of middle age could be useful in screening people for at-risk dementia and encouraging people to make changes to their lifestyle before it's too late," said study author Charles DeCarli, from the University of California at Davis.

The study involved 1,352 dementia-free individuals with an average age of 54 who were given magnetic resonance imaging (MRI) brain scans over a 10-year period.
People with high blood pressure were found to develop white matter hyperintensities faster than those with normal pressure readings.

They also had a more rapid worsening of scores on tests of planning and decision-making.

Those with diabetes in middle age lost brain volume in the hippocampus, a brain region vital to memory, at a faster rate than those without diabetes.

Smokers lost brain volume overall and were also likely to suffer a rapid increase in vascular brain lesions.

Obese participants were more likely to be in the top 25 per cent of people with a faster rate of decline in scores for tests of planning and decision making.