NEW YORK (Reuters Health) – Women seem to be more susceptible to the harmful effects of smoking than their male counterparts, according to findings from a case-control study of subjects with chronic obstructive pulmonary disease (COPD), presented Monday at the international conference of the American Thoracic Society in San Diego.

The current study is not the first to suggest that smoking-related damage is worse in women than in men, lead researcher Dr. Inga-Cecilie Soerheim, from the University of Bergen, Norway, told Reuters Health. “The novel aspect of our study is that we specifically examined subgroups of COPD subjects with either early-onset of disease or low smoking exposure.”

Dr. Soerheim said that her team hypothesized that “if women are more susceptible to smoking-related lung damage, they will likely experience reduced lung function at an earlier age or after less smoking exposure than men.”

To look into that, the researchers studied 954 subjects with moderate or severe COPD and 955 controls. All of the subjects were either current or former smokers.

The researchers found that women had worse lung function and more severe disease than men in subgroups with early-onset COPD (<60 years of age) and low smoking exposure COPD (<20 cigarettes/day for <20 years). "In the low exposure group in this study, half of the women actually had severe COPD," Dr. Soerheim noted in a press release. Dr. Soerheim commented that she and her colleagues were somewhat surprised by how many female smokers had severe COPD with relatively modest smoking histories. These findings have an important public health message, Dr. Soerheim emphasized. “Many people believe that their own smoking is too limited to be harmful — that a few cigarettes a day represent a minimal risk. But there is no such thing as a safe amount of cigarette smoking. Our data suggest that this is particularly true for female smokers.” In addition, she said that the results, “together with other studies demonstrating similar findings, should definitely urge all physicians to be aware of COPD development in female smokers.”