THE risks of passive smoking may have been substantially underestimated.
Previous studies have relied on indirect measures of exposure to smoke, such as looking at the partners of smokers. The latest study, however, is based on blood tests for cotinine, a breakdown product of nicotine that remains in the blood for around two days.
Between 1978 and 1980, more than 2000 men in the UK aged between 40 and 59 years underwent cotinine tests, and their health was monitored over the next 20 years. Researchers at St George鈥檚 Medical School and the Royal Free & University College Medical School in London found that high levels of cotinine among the non-smokers were associated with up to a 60 per cent greater risk of coronary heart disease (British Medical Journal, DOI: 10.1136/bmj.38146.427188.55). Studies of smokers鈥� partners had suggested the increased risk was under 30 per cent. In the latest study, non-smokers with high cotinine levels did not have a higher risk of strokes, however.
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鈥淲e advocate restricting passive smoking wherever possible, including in public places,鈥� says team member Peter Whincup. He supports the 4500 doctors who this week called on the British government to follow the example of places such as California and Ireland and ban smoking in public places.