Second-hand smokers risk dementia

People exposed to second-hand smoke are more at risk of developing dementia, according to scientists.

Previous research found that smoking increases the risk of dementia by damaging the way the brain works, but now a study from the University of Cambridge has shown that people exposed to high levels of second-hand smoke are 44% more likely to suffer cognitive impairment - affecting things like memory and ability to perform calculations.

Researchers, writing in the British Medical Journal, split 4,800 non-smoking adults in England based on their levels of cotinine - a marker of nicotine exposure.