Annals of Oncology Advance Access originally published online on August 18, 2008
Annals of Oncology 2009 20(2):374-378; doi:10.1093/annonc/mdn550
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epidemiology |
Vitamin D intake and breast cancer risk: a case–control study in Italy
1 Department of Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
2 Department of Epidemiology, International Epidemiology Institute, Rockville, USA
3 Department of Hygiene and Epidemiology, University of Athens Medical School, Athens, Greece
4 Department of Epidemiology, Centro di Riferimento Oncologico, Aviano, Italy
5 Department of Medicine, Vanderbilt University Medical Center and Vanderbilt—Ingram Cancer Center, Nashville, USA
6 Department of Epidemiology, Policlinico di Monza, Monza
7 Department of Epidemiology, Fondazione Pascale, Naples, Italy
8 Department of Epidemiology and Biology, International Agency for Research on Cancer, Lyon Cedex, France
9 Department of Epidemiology, Istituto di Statistica Medica e Biometria G. A. Maccacaro, Università degli Studi di Milano, Milan, Italy
* Correspondence to: Dr M. Rossi, Department of Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri, Via G. La Masa 19, 20156 Milan, Italy. Tel: +39-0239014541; Fax: +39-0233200231; E-mail: mrossi{at}marionegri.it
Background: Vitamin D has been suggested to play a protective role against several cancers, including breast cancer.
Patients and methods: We used data from a case–control study conducted in Italy from 1991 to 1994 to study the relation between dietary intake of vitamin D and breast cancer risk. Subjects were 2569 women with incident, histologically confirmed breast cancer and 2588 hospital controls. Odds ratios (ORs) and 95% confidence intervals (CIs) according to deciles of vitamin D intake were estimated by multiple logistic regression models.
Results: After allowance for major risk factors for breast cancer and dietary covariates including calcium and energy intake, there was no association with vitamin D up to the seventh decile. Thereafter, the OR declined, so that the overall trend was statistically significantly inverse. The OR for subjects in the three highest deciles of consumption compared with those in the lowest ones combined was 0.79 (95% CI 0.70–0.90). Intake of vitamin D >3.57 µg or 143 IU appeared to have a protective effect against breast cancer. The inverse association was consistent across strata of menopausal status.
Conclusions: This study adds to the existing evidence that vitamin D intake in inversely associated with breast cancer risk.
Key words: breast cancer, case–control study, risk factors, vitamin D
Received for publication October 30, 2007. Revision received May 5, 2008. Accepted for publication July 9, 2008.