Pregnancy duration and breast cancer risk
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Pregnancy duration and breast cancer risk. / Husby, Anders; Wohlfahrt, Jan; Øyen, Nina; Melbye, Mads.
In: Nature Communications, Vol. 9, No. 1, 4255, 2018, p. 1-7.Research output: Contribution to journal › Journal article › peer-review
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TY - JOUR
T1 - Pregnancy duration and breast cancer risk
AU - Husby, Anders
AU - Wohlfahrt, Jan
AU - Øyen, Nina
AU - Melbye, Mads
PY - 2018
Y1 - 2018
N2 - Full-term pregnancies reduce a woman’s long-term breast cancer risk, while abortions have been shown to have no effect. The precise minimal duration of pregnancy necessary to lower a woman’s breast cancer risk is, however, unknown. Here we provide evidence which point to the protective effect of pregnancy on breast cancer risk arising precisely at the 34th pregnancy week. Using a cohort of 2.3 million Danish women, we found the reduction in breast cancer risk was not observed for pregnancies lasting 33 weeks or less, but restricted to those pregnancies lasting 34 weeks or longer. We further found that parity, socioeconomic status, and vital status of the child at birth did not explain the association, and also replicated our finding in data from 1.6 million women in Norway. We suggest that a distinct biological effect introduced around week 34 of pregnancy holds the key to understand pregnancy-associated breast cancer protection.
AB - Full-term pregnancies reduce a woman’s long-term breast cancer risk, while abortions have been shown to have no effect. The precise minimal duration of pregnancy necessary to lower a woman’s breast cancer risk is, however, unknown. Here we provide evidence which point to the protective effect of pregnancy on breast cancer risk arising precisely at the 34th pregnancy week. Using a cohort of 2.3 million Danish women, we found the reduction in breast cancer risk was not observed for pregnancies lasting 33 weeks or less, but restricted to those pregnancies lasting 34 weeks or longer. We further found that parity, socioeconomic status, and vital status of the child at birth did not explain the association, and also replicated our finding in data from 1.6 million women in Norway. We suggest that a distinct biological effect introduced around week 34 of pregnancy holds the key to understand pregnancy-associated breast cancer protection.
U2 - 10.1038/s41467-018-06748-3
DO - 10.1038/s41467-018-06748-3
M3 - Journal article
C2 - 30353005
AN - SCOPUS:85055461099
VL - 9
SP - 1
EP - 7
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 4255
ER -
ID: 215510408