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Lactation and the risk of breast cancer in an Italian population
Author(s) -
Negri Eva,
Braga Claudia,
La Vecchia Carlo,
Levi Fabio,
Talamini Renato,
Franceschi Silvia
Publication year - 1996
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19960717)67:2<161::aid-ijc1>3.0.co;2-r
Subject(s) - medicine , breast cancer , odds ratio , obstetrics , parity (physics) , population , gynecology , breast feeding , lactation , breastfeeding , case control study , mammary gland , multivariate analysis , confounding , cancer , pregnancy , demography , pediatrics , biology , physics , environmental health , particle physics , genetics , sociology
The relation between breast feeding and breast cancer was investigated in a multicentric case‐control study conducted in Italy on 2,167 parous women with histologically confirmed breast cancer, diagnosed within 1 year, and 2,208 parous control women admitted to hospitals in the same catchment areas of cases for acute, non‐neoplastic, non‐gynecological non‐hormone‐related diseases. Compared with women who had never tried to lactate, those who had always failed had a multivariate odds ratio (OR; adjusted for parity, education and several other potential confounding factors) of 0.94, and those who had lactated had an OR of 1.17. The multivariate ORs of women who had breast fed 1, 2 and 3 or more children were, respectively, 1.14, 1.18 and 1.32, compared with women who had never lactated. None of these ORs was statistically significant. Compared with women who had never breast fed, the multivariate ORs were 1.19 for women reporting less than 6 months of breast feeding, 1.15 for 6–11 months, 1.34 for 12–17 months, 1.10 for 18–23 months and 0.86 for 24 months or more. No appreciable difference was evident across strata of age, menopausal status, parity and age at first birth, while there was a hint of interaction with education. Our study therefore excluded any appreciable protective role for lactation in breast cancer risk, with the patterns of lactation in this European population, aside from the protective role of parity on breast carcinogenesis. © 1996 Wiley‐Liss, Inc.