Oral Contraceptives and Cervical Cancer. Analysis of the Strength of the Association

Abstract

The power of the association between oral contraceptives and cervical cancer was analysed in all the papers published up to date. Fifty-three publications (from 48 studies) wer collected and graded as to quality using meta-analytical methods. Power achieved a figure of >0.8 in a 24% of the associations studied. It showed a significant relationship with the existence of a significant relative risk of the oral contraceptives for cervical cancer, with the quotient between sample sizes of referente and index groups, and with the sample size of a study, although the relationship was not linear to these two latter variables. Power did not show any significant relationship to other variables related to the design of a study, or to the biases detected. Logistic regression analysis included as predictors of a power >0,80 the existence of a significant relative risk and the use of adjusted relative risk.