A paper published online on The British Medical Journal suggests that people who are exposed to second hand smoke are more likely to suffer from cognitive decline in later life.
Researchers looked at 4809 non-smoking adults aged 50 or over who were part of the 1998, 1999 and 2001 Health Survey for England who also participated in the 2002 English Longitudinal Study of Ageing.
Participants provided a salive sample for cotinine testing and were quizzed on smoking habits.
Researchers found that those people whose cotinine levels were highest, but who did not smoke or use nicotine products had the highest risk of cognitive impairment, compared with similar groups whose cotinine levels were lowest.
Cotinine levels are an indication of exposure to tobacco smoke.
Researchers now recommend further studies specifically looking at the risk of dementia.
