NEW YORK — Women who smoke are at a 25% higher risk of developing coronary heart disease than the men who share that smoke break with them, according to a meta-analysis published Wednesday on The Lancet website.
This increased risk for women could be due to physiological differences between the sexes, with cigarette smoke toxins possibly having a more potent effect on women, suggested Rachel Huxley, study co-author at the Division of Epidemiology, University of Minnesota.
The authors' meta-analysis included around 4 million individuals and 67,000 coronary heart disease events from 86 studies. They found that in 75 cohorts (representing a total of 2.4 million participants) that adjusted for cardiovascular risk factors other than coronary heart disease, the pooled adjusted female-to-male relative risk ratio of smoking, compared with not smoking for coronary heart disease, was 25% higher for women. This relative risk ratio 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 compared with a man who has smoked the same length of time.
"Cigarette smoking is one of the main causes of coronary heart 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," Huxley noted. "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 the rise."
The actual risk could be even higher, Huxley added. Women, on average, smoke fewer cigarettes per day than men, for example. "Women might extract a greater quantity of carcinogens and other toxic agents from the same number of cigarettes than men," Huxley wrote. "This occurrence could explain why women who smoke have double the risk of lung cancer compared with their male counterparts."