Adults who smoke heavily develop poorer memories in middle age, according to a new British study .
It suggests smokers who survive the biggest dangers – lung cancer and heart disease – may be at risk from dementia in old age.
Researchers at University College London studied 2,000 adults as part of a broader tracking of the health of thousands of people born in Britain in 1946.
Some of the participants took memory, concentration and visual speed tests aged 43 and again at 53.
Heavy smoking – more than 20 cigarettes a day – was associated with faster declines in verbal memory and visual speed, although the declines were small.
The scientists will continue tracking the participants to see how their brains fare as get older.
The UCL study was published in the American Journal of Public Health today.
Other research has already identified smoking as a possible contributor to dementia.
One cause of dementia is restricted blood flow in the brain, and smoking is linked to narrowed arteries and silent mini-strokes that choke that blood supply.