Smoking harms women's hearts more than men's
If you are a woman who smokes, you increase your chances for heart disease by a whopping 25 percent. You also have double the risk of lung cancer compared with your male counterparts. That’s the conclusion reached by a study published online Thursday in The Lancet.
The study is a large meta-analysis of past studies on smoking, spanning almost five decades. Researchers reviewed data on smoking and health from 86 previous studies published between 1966 and 2011. In addition to showing that female smokers' heart disease risk is 25 percent higher, the pooled data showed that a woman's extra risk increases 2 percent for each additional year she smokes.
The greater risk for women is attributable to both physiological differences between the sexes and the fact that women smoke differently from men. The net effect is that women might extract a greater quantity of carcinogens and other toxic agents from the same number of cigarettes than men, study authors Dr. Rachel Huxley of the University of Minnesota and Dr. Mark Woodward of Johns Hopkins University, concluded.
Women carry a proportionately higher percentage of body fat than men, and since fat is known as a storehouse, it has been demonstrated to retain various compounds, including toxic substances. In fact, one of the side benefits of losing body fat is the detoxifying effect the loss produces. It makes sense, then, that women will more readily store the noxious by-products of smoking, many of which are known carcinogens or free radicals which damage healthy tissue.
In addition to heart disease and lung cancer, smoking is known to raise the risk for emphysema, stroke, infertility, sudden infant death syndrome, reduced bone density, and various other forms of cancer, including malignancies of the bladder, esophagus, kidney, stomach, and uterus.
"What makes the realization that women are at increased risk worrisome is that the tobacco industry views women as its growth market," wrote Matthew A. Steliga, MD, and Carolyn M. Dresler, MD, from the University of Arkansas in Little Rock, in an accompanying commentary.
Smoking among men has been steadily declining over the past few decades, while women’s rates of smoking have only leveled out in the past decade. This translates into substantial, preventable future rates of coronary heart disease morbidity and mortality that will outstrip those of men’s.
Researchers also examined the risk in relation to various age groups, from 30 to 80 years or older. Except for those between 30 and 44 years, women in all other age groups had a greater risk of coronary heart disease than men. The difference became significant in those between 60 and 69 years.
Even men who quit smoking fared better than women who did so.
The study, published in the Lancet, is limited by its lack of standardization for dose and duration of smoking, inability to adjust for oral contraceptive use, and the various definitions of "non-smokers" used in the studies.
In the U.S., tobacco use is responsible for about one in five deaths, or about 443,000 deaths a year. On average, smokers die 13 to 14 years earlier than nonsmokers. Twenty-one percent of American adults smoke.