( e at work the primary places for long-...)Indicators for risk of heart disease are higher in passive smokers

Researchers found the low- and high-cotinine groups had significantly higher levels of fibrinogen and homocysteine than the 'no detectable' group, with fibrinogen levels estimated at 9?0 milligrams per decilitre higher and homocysteine levels at 0.8 micromoles per litre higher.

Dr Venn said: "The increased levels of fibrinogen and homocysteine seen in relation to second-hand smoke exposure were equivalent to about 30 per cent to 45 per cent of those seen for active smoking."

The researchers also investigated elevated C-reactive protein, another inflammatory marker, and white blood cell count in participants with elevated cotinine levels. They found no significant association.

The effect levels seen for fibrinogen and homocysteine were about twice as high when measuring cotinine levels compared to previous studies based on self-reported exposure.

The association changed little even after researchers adjusted for participants' self-reported fruit and vegetable consumption ?one of the more influential aspects of diet on cardiovascular health ?and for lifestyle factors such as physical activity, social class and obesity. Restricting analysis to those 70 or younger with no history of heart attack, heart failure or stroke also made lifwttle difference in the association.

Dr Venn said: "Our study shows that very low levels of exposure to second-hand smoke may be associated with appreciable increases in cardiovascular risk. While the cotinine levels were on average only about 0.1 percent of those in active smokers, the apparent effects of passive smoking on the biomarkers were about one-third to one-half those for active smoking."

The associations with fibrinogen and homocysteine observed in the study translate into an increase in a disease risk of five per cent, although the combined effect due to other processes is likely to be closer to 30 percent,
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Source:University of Nottingham