Indicators for risk of heart disease are higher in passive smokersFebruary 13, 2007Exposure to second-hand smoke at work, home or elsewhere results in a disproportionate rise in markers that increase the risk of cardiovascular disease, University of Nottingham researchers have found. A new study published in Circulation, a journal of the American Heart Association, measured the level of cotinine in participants' blood, rather than relying on participants' self-reporting of exposure to second-hand smoke. Cotinine is the major metabolite of nicotine that indicates levels of nicotine intake. Since nicotine is highly specific for tobacco smoke, blood serum cotinine levels track exposure to tobacco smoke and its toxic components. Dr Andrea Venn, lead author of the study and associate professor in the Division of Epidemiology and Public Health at The University of Nottingham, said: "Our study provides further evidence to suggest low level exposure to second-hand smoke has a clinically important effect on susceptibility to cardiovascular disease. "This is the first epidemiological study to relate the levels of these markers to an objective measure of second-hand smoke exposure, rather than self-reported exposure, which can be biased." Dr Venn and co-author Professor John Britton checked to see if people exposed to second-hand smoke had increased levels of fibrinogen, homocysteine and C-reactive protein — all markers of cardiovascular disease. Researchers examined data from the third National Health and Nutrition Examination Survey (NHANES III, 1988-94), which included 7,599 adults who had never smoked. Sixty-eight percent of the participants were women, with participants' median age being 38. Eighteen percent of participants had no detectable levels of cotinine; the rest were classified as having either low or high cotinine. Eighteen percent of participants with low levels of cotinine and 56 percent of subjects with high levels of cotinine reported living with a smoker at home or being exposed to tobacco smoke at work, the primary places for long-term exposure. 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 9-10 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, Dr Venn said. "Even when participants weren't exposed to smoke at the workplace or at home, many had low or high levels of cotinine in their blood," Dr Venn said. "These people may be exposed in bars or restaurants or perhaps in other people's homes such as those of relatives or friends. This suggests that even people exposed to low levels of second-hand smoke may be at increased risk. "This study supports existing evidence that exposure to second-hand smoke is an important avoidable cause of cardiovascular disease. It also highlights the importance of implementing measures to protect the public from second-hand smoke such as banning smoking in enclosed public places and workplaces," Dr Venn added. A smoking ban applying to all UK public spaces comes into force on July 1, 2007. University of Nottingham |
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| Related Second-hand Smoke Current Events and Second-hand Smoke News Articles A consistent decline in heart attack rates following the implementation of smoking bans Strongly enforced legislation to restrict smoking produces rapid and substantial reductions in community rates of heart attack, according to a meta-analysis published today in Circulation, the journal of the American Heart Association. Guide on lung cancer in 'never-smokers': A different disease and different treatments A committee of scientists led by Johns Hopkins investigators has published a new guide to the biology, diagnosis and treatment of lung cancer in never-smokers, fortifying measures for what physicians have long known is a very different disease than in smokers. Second-hand smoking results in liver disease, study finds A team of scientists at the University of California, Riverside has found that even second-hand tobacco smoke exposure can result in nonalcoholic fatty liver disease (NAFLD), a common disease and rising cause of chronic liver injury in which fat accumulates in the liver of people who drink little or no alcohol. A child's IQ can be affected by mother's exposure to urban air pollutants A mother's exposure to urban air pollutants known as polycyclic aromatic hydrocarbons (PAHs) can adversely affect a child's intelligence quotient or IQ, a study reports. Children's IQ can be affected by mother's exposure to urban air pollutants Prenatal exposure to environmental pollutants known as polycyclic aromatic hydrocarbons (PAHs) can adversely affect a child's intelligence quotient or IQ, according to new research by the the Columbia Center for Children's Environmental Health (CCCEH) at the Mailman School of Public Health. Blood tests reveal tobacco smoke residues in non-smoking New Yorkers More than half of non-smoking New Yorkers have elevated levels of cotinine in their blood - meaning that they were recently exposed to toxic second-hand smoke in concentrations high enough to leave residues in the body. Passive smoking link to dementia Researchers from the Peninsula Medical School, the University of Cambridge and the University of Michigan have published the results of the first large-scale study to indicate that second-hand smoke exposure could lead to dementia and other neurological problems. Tobacco Smoke and Alcohol Harm Liver Worse as Combo Exposure to second-hand smoke and alcohol significantly raises the risk of liver disease, according to researchers at the University of Alabama at Birmingham (UAB). Third-hand smoke: Another reason to quit smoking Need another reason to add "Quit Smoking" to your New Year's resolutions list? How about the fact that even if you choose to smoke outside of your home or only smoke in your home when your children are not there - thinking that you're keeping them away from second-hand smoke - you're still exposing them to toxins? Smokers see decline in ability to smell, rise in laryngitis, and upper airway issues As Americans prepare for a day without cigarettes and tobacco products as part of the American Cancer Society Great American Smokeout (R) (November 20), new research gives them more reasons to extend that break to a lifetime. More Second-hand Smoke Current Events and Second-hand Smoke News Articles |
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