Sex, smoking, and cancer: a reappraisal.

Several studies (1–4) have reported that the relative risk of cancer in smokers, compared with nonsmokers, is greater in women than in men. These results have led to speculations about the biologic mechanisms underlying this difference, such as a molecular interaction between sex hormones and tobacco carcinogens. The news media have echoed widely such results, perhaps because anything suggesting that women and men are inherently different strikes a chord among the public. In this commentary, I suggest that the evidence from these studies is interpreted incorrectly, because of misunderstandings about the meanings of relative risk versus absolute risk and the meanings of statistical interaction versus biologic interaction.