Oral contraceptives significantly reduce the risk of colorectal cancer, according to a meta-analysis published in the British Journal of Cancer.
Researchers from France, Italy, and Spain conducted a meta-analysis of published studies on the association between use of combined oral contraceptives and risk of colorectal cancer.
Articles considered were epidemiological studies published as full papers in English up to June 2000 that included quantitative information on oral contraceptive use. A total of 8 case-control studies and 4 cohort studies were analyzed.
The team found that the pooled relative risk (RR) of colorectal cancer, from the case-control studies, was 0.81 among women who had ever used oral contraceptives. The pooled estimate from the cohort studies was 0.84.
The investigators found that the pooled estimate from all studies combined was 0.82, without apparent heterogeneity.
|Women who have taken oral contraceptives are 18% less likely to develop colorectal cancer.
|British Journal of Cancer|
Duration of use was not associated with a decrease in risk. However, there was some indication that the apparent protection was stronger for women who had used oral contraceptives more recently (RR = 0.46).
Dr E. Fernandez and colleagues concluded, "A better understanding of this potential relation may help informed choice of contraception."