Women smokers are far more likely to be killed by their habit today than they were in the 1960s, a major study has found.
The increased risk greatly outweighs improvements in medicine that have cut death rates among the majority of the population in the past 50 years.
In the 1960s, smoking raised a woman's chances of dying from lung cancer by 2.7 times. By the period 2000 to 2010 this had surged to a 25.7-times' higher level of risk.
Paradoxically, there could be a link between higher death rates and the rise in popularity of milder, "light" cigarettes, according to study leader Dr Michael Thun, from the American Cancer Society.
He said: "The steep increase in risk among female smokers has continued for decades after the serious health risks from smoking were well established, and despite the fact that women predominantly smoked cigarette brands marketed as lower in tar and nicotine.
"So not only did the use of cigarette brands marketed as 'light' and 'mild' fail to prevent a large increase in risk in women, it also may have exacerbated the increase in deaths from chronic obstructive lung disease in male smokers, since the diluted smoke from these cigarettes is inhaled more deeply into the lungs of smokers to maintain the accustomed absorption of nicotine."
Women smokers today start their habit earlier than they did generations ago, and until recently smoked more cigarettes per day. Tobacco use among women peaked in the 1980s, having an impact that was felt years later.
The study involved more than 2.2 million men and women aged 55 and older and included data from 1959 to 2010.
The findings strongly confirm the claim that "if women smoke like men, they will die like men", say the researchers.
Quitting smoking at any age dramatically reduces death rates from all major diseases caused by smoking, the study found.