Behavioural risk factors for cervical cancer from a prospective study in Khon Kaen, Northeast Thailand.

Fifty seven cases of cancer of the cervix were identified within a cohort of 16,648 women enrolled in a cohort study of lifestyle and cancer in a rural population of Northeast Thailand. They were compared with 228 matched controls from the same cohort, with respect to demographic, behavioural and reproductive factors potentially associated with risk of the disease. Number of pregnancies and age at having first child were associated with the risk of cervical cancer, but in contrast to studies elsewhere, age at having first sexual intercourse, number of sexual partners and sexually-transmitted infections were not associated with risk. The lack of effect may be simply due to the small size of the study. But it is also likely that these aspects of female sexual behaviour are not very relevant in a relatively conservative rural population. These aspects may be investigated further in future, as new incident cancers are accrued into the cohort.