Uterine cervical cancer risk in cigarette smokers: a meta-analytic study

We conducted a meta-analytic study to measure the risk of uterine cervical cancer in former and current smokers. A literature search from 1966 to 1988 identified 139 MEDLINE citations. Of these, five studies reported appropriate and complete data for meta-analysis. A recent study conducted by the authors was also included. The graphical and variance-based methods of meta-analysis consistently demonstrated a significantly excessive risk of cervical cancer in current smokers, but not in former smokers. The powers of the analyses involving former smokers were between 0.72 and 0.99, depending on the degree of confounding attributed to unmeasured variables. Thus, it was unlikely that sample size accounted for the null association observed in former smokers. These findings have important medical implications for women in light of the prevalence of cigarette smoking. During regular gynecologic screening examinations, health care professionals may have considerable impact by counseling women about the risk of cervical cancer in smokers. Antismoking messages should be strongly directed toward women in the lower educational and socioeconomic levels to have the greatest impact on the incidence of cervical cancer.