Parity as a risk factor for cervical cancer

Area of Science:

• Epidemiology
• Oncology
• Reproductive Health

Background:

• Invasive cervical cancer (ICC) remains a significant global health concern.
• Reproductive history, including parity, has been implicated as a risk factor for ICC.
• The specific mechanisms linking parity to ICC risk require further elucidation.

Purpose of the Study:

• To investigate the association between the number of pregnancies and invasive cervical cancer risk.
• To examine the role of live births versus pregnancy losses in this association.
• To explore potential modifying factors such as menopausal status and oral contraceptive use.

Main Methods:

• A case-control study was conducted with 759 ICC patients and 1,430 controls across four Latin American countries (1986-1987).
• Data were collected on reproductive history, sexual behaviors, socioeconomic status, and oral contraceptive use.
• Human papillomavirus (HPV) types 16 and 18 infections were assessed using filter in situ hybridization.

Main Results:

• A consistent association between the number of pregnancies and ICC risk was observed, persisting after adjustments.
• Risk increased with higher parity, reaching 5.1-fold for women with 14 or more pregnancies.
• The association was stronger with live births and more pronounced in premenopausal women and oral contraceptive users.
• HPV 16/18 did not explain the observed parity-risk relationship.

Conclusions:

• Multiparity is a significant risk factor for invasive cervical cancer, independent of sexual and socioeconomic factors.
• Reproductive factors, particularly the number of live births, warrant further investigation in cervical cancer etiology.
• Potential mechanisms, including hormonal influences and cervical trauma, should be explored to understand the parity-ICC link.