Results
In the cohort, 123 (5.9%) women developed breast cancer during the mean follow-up of 38.9 years. The mean age at diagnosis was 56.0 years (range 35-74). Background characteristics and index pregnancies are described by tertiles of pregnancy weight gain in Table 1 . Low pregnancy weight gain (<11 kg) was associated to slightly higher [...]
Methods
The Cohort
The study population was a historic cohort of women pregnant between 1954 and 1963 in Helsinki, Finland (n = 4,090). The cohort was a sample gathered for a study on hormone exposure, including 2,022 exposed, 2,062 controls and 6 women with unknown hormone exposure status. Information on the cohort was collected from the maternity [...]
Elevated pregnancy estrogen levels are associated with increased risk of developing breast cancer in mothers. We studied whether pregnancy weight gain that has been linked to high circulating estrogen levels, affects a mother’s breast cancer risk.