Perinatal exposures and breast cancer risk in the Western New York Exposures and Breast Cancer (WEB) Study.
BACKGROUND
There is increasing evidence that early life exposures, such as birth weight, infant feeding practices, birth rank and maternal age at delivery may play a role in breast carcinogenesis.


METHODS
We conducted a case-control study of women aged 35-80 in Western New York (Western New York Exposure and Breast Cancer Study, the WEB Study, 1996-2001). The study included 845 women diagnosed with primary, incident, histologically confirmed breast cancer, and 1538 controls frequency-matched to cases on age, race, and county of residence. We conducted extensive in-person interviews including self-reported birth weight, history of having been breastfed, birth rank, and maternal age at delivery.


RESULTS
Birth weight was significantly associated with pre- but not post-menopausal breast cancer risk. Compared to women whose birth weight was 5.5-7 pounds, we found an increased risk associated with a birth weight greater than 8.5 pounds (OR 1.84, 95%CI: 1.12-3.02). Risk was also increased for pre- but not post-menopausal women who had not been breastfed (OR 1.78, 95%CI: 1.21-2.60). Birth order and maternal age at delivery were not significantly associated with breast cancer risk.


CONCLUSIONS
Our findings are consistent with other studies showing breast cancer risk associated with birth weight for pre- but not post-menopausal breast cancer. As we found in an earlier study, having been breastfed was associated with decreased risk. These findings add to the accumulating evidence that early life events impact women's subsequent breast cancer risk.
Barba
Maddalena
M
Department of Social and Preventive Medicine, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA. barba@ifo.it
McCann
Susan E
SE
Nie
Jing
J
Vito
Domenica
D
Stranges
Saverio
S
Fuhrman
Barbara
B
Trevisan
Maurizio
M
Muti
Paola
P
Freudenheim
Jo L
JL
D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001722:Birth Order; D001724:Birth Weight; D001942:Breast Feeding; D001943:Breast Neoplasms / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D009518:New York; D017698:Postmenopause; D011247:Pregnancy; D017697:Premenopause; D012307:Risk Factors