Breastfeeding and the risk of epithelial ovarian cancer in an Italian population.
OBJECTIVE
Breastfeeding has been inversely related to the risk of ovarian cancer, but results from published studies are inconsistent. In order to provide further information, we analyzed data from a large case-control study conducted in four Italian areas.


METHODS
Cases were 1031 women with epithelial ovarian cancer. Controls were 2411 women admitted to the same network of hospitals for a wide spectrum of acute non-neoplastic conditions, unrelated to known risk factors for ovarian cancer.


RESULTS
There were inverse trends in risk with increasing duration of breastfeeding and number of children breastfed, but when parity and several other potential confounding factors were taken into account, no residual association was evident (odds ratio = 1.21 for 17 or more months of breastfeeding and 0.90 for those who had breastfed 4 or more children, as compared to women who had never breastfed).


CONCLUSIONS
This study showed an inverse relation between breastfeeding and ovarian cancer risk, which however was accounted for by parity. The analyses by histologic subtypes suggested that a role of breastfeeding would be larger for serous neoplasms in the absence, however, of significant heterogeneity.
Istituto di Ricerche Farmacologiche "Mario Negri", Via Eritrea, 62-20157 Milan, Italy. chiaffarino@marionegri.it
Francesca
F
Chiaffarino
Claudio
C
Pelucchi
Eva
E
Negri
Fabio
F
Parazzini
Silvia
S
Franceschi
Renato
R
Talamini
Maurizio
M
Montella
Valerio
V
Ramazzotti
Carlo
C
La Vecchia
D000328:Adult; D000368:Aged; D001942:Breast Feeding; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000453:epidemiology*; D010298:Parity; D012044:Regression Analysis; D012307:Risk Factors