Dr Tom Heffernan and Dr Terence O'Neil, both researchers at the Collaboration for Drug and Alcohol Research Group at Northumbria University, compared a group of smokers with two groups of non-smokers – those who were regularly exposed to second-hand smoke and those who were not.
Those exposed to second-hand smoke either lived with smokers or spent time with smokers, for example in a designated smoking area, and reported being exposed to second-hand smoke for an average of 25 hours a week for an average of four and a half years.
The three groups were tested on time-based memory (remembering to carry out an activity after some time) and event-based memory (which refers to memory for future intentions and activities).
Researchers found that the non-smokers who had been exposed to second-hand smoke forgot almost 20% more in the memory tests than those non-smokers not exposed. However, both groups out-performed the current smokers who forgot 30% more than those who were not exposed to second-hand smoking.
Dr Heffernan said: "Our findings suggest that the deficits associated with second-hand smoke exposure extend to everyday cognitive function."
