Induced abortion and breast cancer

摘要

Sir The study by Braiiner et al. in the June 2013 issue (1) is to be welcomed as throwing some light on breast cancer incidence among women who have had induced abortions, when linking of such records tends to be difficult. In Denmark there are national registry data available. This was accessed to retrieve records of breast cancer and immigration, but not for abortion. Linking to national records for abortion would also remove much of potential underreporting of abortions among the women in the study who did not report induced abortions. Braiiner et al. conclude (in their Abstract) that "Our study did not show evidence of an association between induced abortion and breast cancer risk." But the findings are not very conclusive: the 95% confidence intervals for all the hazard ratios for all the subgroups and the whole study group straddle 1.0. Underreporting of abortions in the study could further widen the confidence intervals.