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Attributable risks for breast cancer in Italy: Education, family history and reproductive and hormonal factors
Author(s) -
Tavani Alessandra,
Braga Claudia,
La Vecchia Carlo,
Negri Eva,
Russo Antonio,
Franceschi Silvia
Publication year - 1997
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(19970117)70:2<159::aid-ijc4>3.0.co;2-w
Subject(s) - breast cancer , family history , hormone , gynecology , medicine , physiology , cancer , oncology
The percent population attributable risk (AR) for breast cancer was estimated in relation to education, family history of the disease and some reproductive and hormonal factors, using data from a case‐control study conducted between June 1991 and February 1994 in 6 Italian centres on 2,569 histologically confirmed incident breast cancer cases and 2,588 controls, admitted to hospital for a wide range of acute, non‐neoplastic, non‐hormone‐related diseases. On the basis of multivariate odds ratios, a high level of education accounted for 20% of cases, elevated age at first birth and nulliparity for 38% and a family history of breast cancer in first‐degree relatives for 7%. Education and nulliparity and age at first birth together explained 47% of all breast cancer cases, and the combination of these 2 factors plus a family history of the disease explained 50% of cases. In pre‐menopausal women a high level of education accounted for 31% of all breast cancer cases, older age at first birth for 44% and the combination of the 2 factors for 49%. In post‐menopausal women the corresponding values were 13%, 31% and 42%; further addition of risk associated with family history of the disease explained 52% of pre‐menopausal cases. In post‐menopausal women older age at menopause and the use of hormone replacement therapy accounted for 15% and 2% of breast cancer cases, respectively. The combination of risks associated with a high level of education, old age at first birth and nulliparity and older age at menopause accounted for 51% of cases; further inclusion of risk associated with use of hormone replacement therapy explained 52%, and the AR resulting from these 4 risk factors combined plus a family history of breast cancer was 56%. Thus, a few selected and well‐identified risk factors explain about one‐half the breast cancer cases in this Italian population. Int. J. Cancer, 70:159–163, 1997. © 1997 Wiley‐Liss, Inc.