Trends in differential breast cancer mortality, Belgium 1991-1995 – 2004-2005

Sylvie Gadeyne, Vrije Universiteit Brussel
Patrick Deboosere, Vrije Universiteit Brussel
Hadewijch Vandenheede, Vrije Universiteit Brussel

This study investigates trends in differential breast cancer mortality in Belgium and the role of reproductive factors herein. Several studies have shown that the association between breast cancer and educational level has changed during the last decades, moving from a positive association to a non-existent or a negative association. Reproductive factors have often been held responsible for the relationship and changing patterns, but their effects have seldom been quantified. The Belgian data show that in 1991-95, lower educated women have higher mortality rates for breast cancer, at least among postmenopausal women. The association can mainly be explained by reproductive factors, i.e. mean number of children and age at first birth. In 2004-05, the situation has changed, educational differences no longer being significant. Among premenopausal women there is even a tendency towards an inversion of the 1991-95 pattern, specifically after control for reproductive factors.