Aug. 10, 2011 -- Women smokers run a 25% higher risk than male smokers of developing coronary heart disease, according to a recent study. The authors of the study suggest that this increased risk for women could be due to physiological differences between the sexes.
The study, by Rachel R. Huxley, DPhil, of the division of epidemiology at the University of Minnesota, and Mark Woodward, PhD, of Johns Hopkins University in Maryland, is published in the journal The Lancet.
The authors' findings are based on an analysis of 86 previous studies involving more than 4 million people. In 75 study groups, researchers had taken account of risk factors for heart and vascular disease other than CHD itself. Among the 2.4 million participants in these studies, they found that the risk of smoking compared with not smoking was 25% higher among women than men.
This increased relative risk among women was further increased by 2% for every additional year of follow-up, meaning that the longer a woman smokes, the higher her risk of developing heart disease becomes when compared with a man who has smoked for the same length of time.
The authors say: "Cigarette smoking is one of the main causes of coronaryheart disease worldwide and will remain so as populations that have so far been relatively unscathed by the smoking epidemic begin to smoke to a degree previously noted only in high-income countries. This expectation is especially true for young women in whom the popularity of smoking, particularly in some low-income and middle-income countries, might be on therise."
The actual relative risk may be even higher, say the authors. Women, on average, smoke fewer cigarettes per day than men, and in many countries the smoking epidemic in women has been much shorter in duration. Both these factors mean that the relative risk for women compared with men could actually be even higher.
Women May Take in More Carcinogens
According to the authors: "The finding that, among smokers, the excess risk of coronary heart disease in women compared with men increases by 2% for every extra year of study follow-up lends support to the idea of a pathophysiological [differing bodily responses] basis for the sex difference. For example, women might extract a greater quantity of carcinogens and other toxic agents from the samenumber of cigarettes than men. This occurrence could explain why women who smoke have double the risk of lung cancer compared with their male counterparts."
The authors conclude that doctors and health professionals should be encouraged to increasetheir efforts in promoting smoking cessation in all individuals. However, they say, "Present trends in female smoking, and this report, suggest that inclusion of a female perspective in tobacco-control policies is crucial."