Risk factors for adenocarcinoma of the cervix: a case-control study

Abstract

To assess risk factors for cervical adenocarcinoma data were collected in a case-control study of 39 cases and 409 controls conducted in the greater Milan area. Questions were asked about personal characteristics and habits, gynaecologic and obstetric data, history of lifetime use of oral contraceptives and other female hormones, and general indicators of sexual habits (age at first intercourse and total number of sexual partners). The relative risk of cervical adenocarcinoma increased with number of births and abortions, early age at first birth and early age at first intercourse. These estimates did not materially change after adjustment for the potential reciprocal confounding effect. Further, there was a positive association with overweight, but an apparent association with lower education was not significant. No relationship emerged with oral contraceptive use. Thus, despite the similarities with the epidemiology of squamous cell cancer, reproductive patterns and other factors related to the risk of endometrial cancer (i.e., overweight) seem to play an important role in the risk of adenocarcinoma of cervix uteri.

PIP: A case control study of 39 cases of cervical neoplasia and 409 controls was conducted in the greater Milan area to assess risk factors for cervical adenocarcinoma. The relative risks of adenocarcinoma of the cervix were computed together with their 95% approximate confidence intervals (CI) from data stratified for quinquennia of age by the Mantel-Haenszel procedure. When a factor could be classified in more than 2 levels, the significance of the linear trend was assessed by the Mantel test. In the computation of relative risks, the potential reciprocal confounding effects of the major known or potential risk factors for adenocarcinoma of the cervix were controlled for using stratification and the Mantel-Haenszel procedure. The risk of cervical adenocarcinoma increased with number of births, the point estimates being 1.2 for women with 1 or 2 and 3.6 for those with 3 or more births. Among parous women, the risk decreased with increasing age at 1st birth. This negative association, like the positive relation with parity, was independent of major indicators of sexual habits. Increased frequencies of spontaneous and induced abortions throughout the period of reproductive life were observed in women with adenocarcinoma of the cervix. These positive associations were independent of parity. There was no relation between cervical adenocarcinoma and age at menarche, menopausal status, age at menopause, and lifelong menstrual pattern. Risk estimates decreased with increasing age at 1st intercourse being, compared to women aged 17 years or less at 1st intercourse, 0.3 and 0.2 respectively for women aged 18-20 and over 21 or no intercourse. The number of sexual partners was associated with risk of cervical adenocarcinoma. Compared to women with only 1 (or no) partner, women with 2 or more sexual partners had a relative risk of 1.7. Adjustment of the sexually-related risk estimates for the major reproductive variables failed to modify any of the results, confirming that these 2 groups of factors have an independent effect on the risk of cervical adenocarcinoma. There also was no appreciable interaction between age at 1st birth and parity on the risk of adenocarcinoma.