Are women more sensitive to smoking than men? Findings from the Renfrew and Paisley study

Background Prescott et al. found that the relative risks associated with sm oking for respiratory and vascular deaths were higher for women who inhale than for inhaling men, and found no gender differences in relative risks of smoking-related cancers. The purpose of the present study was to assess wh ether these findings are reproducible, using data from the Renfrew and Pais ley study. Methods Age-standardized mortality rate differences and age-adjusted mortal ity rate ratios (using Cox's proportional hazard model) were calculated for male and female smokers by amount smoked compared with never smokers. Thes e analyses were repeated after excluding non-inhalers. Results The all-cause mortality rate ratio was higher for men than for wome n in all categories of amount smoked, although this difference was only sta tistically significant in the light smokers (1.83 [95 % CI: 1.61-2.07] for men and 1.41 [95 % CI: 1.28-1.56] for women, P=0.001). The cause-specific m ortality rate ratios tended to be higher for men than for women, and this d ifference was most substantial for neoplasms (2.57 [95% CI: 2.01-3.29] for male light smokers and 1.35 [95% CI: 1.14-1.61] for female light smokers, P <0.001) and, in particular, for lung cancer (11.10 [95% CI: 5.89-20.92] for male light smokers and 4.73 [95% CI: 2.99-7.50] for female light smokers, P=0.03). Furthermore, looking at the rate differences the effects of smokin g were uniformly greater in men than in women. These results were virtually unchanged after excluding non-inhalers. Conclusion We found similar results to Prescott et al. when all smokers wer e considered, but could not reproduce their findings when non-inhalers were excluded. Given the fact that we showed greater rate differences in men th an in women, we think that it is too early to conclude that women may be mo re sensitive than men to some of the deleterious effects of smoking.