Friday, Mar. 04, 1966
The Smoking Woman
Throughout the 15-year wrangle over the effects of smoking on health, women smokers have offered a medical conundrum. Although they puff at cigarettes with the same freedom as men, they do not suffer as much lung cancer. Why?
The answer, Statistician E. Cuyler Ham mond of the American Cancer Society reported last week, is devastatingly sim ple: for all their freedom, modern wom en do not smoke as much as men. On the average, they do not start smoking as young, do not inhale as deeply, and have not smoked for as many years. Hammond's statistics also show, however, that the closer women's smoking practices approach men's, the closer are their disease and death rates.
In a detailed comparison of the smoking and health histories of 441,000 men and 563,000 women, Dr. Hammond's crew of epidemiologists followed the medical history of their volunteers since the winter of 1959-60. The first result of their work was the world's most exhaustive survey of the relationship between men's smoking and disease (TIME, Dec. 13, 1963), a study that was a major factor in persuading the U.S. Public Health Service to condemn smoking. By now, the Cancer Society researchers have followed both the men and the women for four years, and have tracked down the cause in 97% of the 43,000 deaths among the subjects. The delay in reporting the data on women reflects the fact that female death rates from virtually all causes are lower than the death rates among males; the Hammond staff had to wait for enough women to die to give them a valid statistical sample.
Three Factors. More men than women smoke cigarettes (47% of men aged 35 and up, as against 27% of women), and the disparity in smoking habits is notably greater in the older age groups. In the 35-44 age group (the youngest for which data on smoking and health are meaningful), women who limit themselves to less than half a pack a day outnumber men 3 to 1; those who stop at a pack a day outnumber men 2 to 1. Deep inhaling is half as common among the 35-44 women as among men, and only one-third as common in the 55-64 age bracket.
The sampling of current smokers shows that as recently as the 1930s, only one-third as many girls as boys started smoking before they were 15; this is significant because disease and death rates, notably for lung cancer, are related to duration of smoking. All three factors --age of starting, inhalation habits and number of cigarettes smoked--said Dr. Hammond, tend to go together: a boy or a girl who starts smoking before age 15 is more likely to become a heavy smoker and deep inhaler.
Women smokers in the 45-54 age group, Hammond's statistics show, have a death rate 1.31 times higher than that of nonsmokers. And the rate goes up with the number of cigarettes smoked: it is 1.54 times the rate for nonsmokers among women in the one-to-two-packs-a-day range, and 1.96 times as high for those using more than two packs a day. The mortality rates follow practically the same patterns when computed in relation to depth of inhaling and age at which smoking began.
Innate Advantage. Comparison of lung cancers in men and women is complicated by the fact that the disease is not the same in the two sexes--wom en are more liable to some uncommon forms, which all researchers agree are unrelated to smoking. In the Hammond study, lung cancer caused 1,159 deaths, or 4.5% of the total, among men, but only 210 deaths, or 1.3%, among women. In cases where the cancer type could be determined, two-thirds of the men had the form associated with long-continued smoking; so did half of the women. The researchers concluded that women who have smoked at any time in their lives run a 2.2 times greater risk of dying from lung cancer than nonsmokers, with a peak at 2.82 times in the 40-54 age range.
Despite the fact that his statistics show that heavy-smoking women have higher disease and early-death rates, Dr. Hammond finds that most of them still do not fare as badly as men. Their increased risk of heart-artery disease (almost twice as much as nonsmokers') and of lung cancer is only about half as great as the smoking man's increased risk. The truth is, women seem to have an inherent biological superiority and survival capacity over men. The difference in overall number of deaths among the Cancer Society volunteers is striking: there were more than half as many again among the men, although there were many fewer men in the study. Even if enough women smoked heavily enough and long enough to incur the same added risk of early death as male smokers, says Dr. Hammond, the actual death rates among women would still be lower because of that innate superiority.
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