The main established reproductive risk factors for breast cancer
are nulliparity, late age at first birth, early age at menarche and late
age at menopause;while prolonged breastfeeding reduces
risk.Our results are not in close accord with these observations,
but are not sufficiently robust to suggest that having children is
irrelevant to the risk of developing breast cancer in this population.
However, breast cancer risk may be elevated in the years immediately
following a pregnancy, so a protective effect may not be
apparent in this younger group of women.