Document Type : Original Article

Authors

1 Department of Surgery, Zanjan University of Medical Sciences, Zanjan, Iran

2 Department of Hematology-Oncology, School of Medicine, Zanjan, University of Medical Sciences, Zanjan, Iran

3 Department of Immunology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran

4 Social Determinants of Health Research Center, Zanjan University of Medical Sciences, Zanjan, Iran

5 Department of Epidemiology and Statistics, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran

10.30476/mejc.2021.85406.1279

Abstract

Background: The protective role of vitamin D in the occurrence of breast cancer is nowadays a controversial matter. Based on conflicting results of the studies in this field and also considering the prevalence of vitamin D deficiency in Iranian women, this work was conducted to evaluate the association between vitamin D and breast cancer.
Method: This matched case-control study was conducted on 70 newly diagnosed breast cancer patients and 70 controls with the same age, menopause status, and time of blood sampling in Zanjan. Information regarding demographic, reproductive, history of diseases, medication, use of dairy products, and sunlight exposure was collected using a questionnaire. The serum level of vitamin D was measured with ELISA method. The data were analyzed utilizing Chi-square test, Independent T-test, and Odds Ratios using Conditional logistic regression model.
Results: The mean level of vitamin D was 39.04 and 63.34 ng/ml in the cases and controls, respectively (P=0.046). The proportion of the cases in the highest quartile of vitamin D was significantly smaller than that in the controls compared to the lowest quartile (Ptrend=0.028). Using Conditional logistic regression model, an inverse and independent association was observed between vitamin D and breast cancer after controlling main confounders. The risk of breast cancer was independently associated with BMI and low income.
Conclusion: In this study, an inverse association was confirmed between vitamin D and breast cancer. Prospective intervention studies should be performed to explore its role in the prevention of breast cancer.

Keywords

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination, and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi:10.30476/mejc.2021.85406.1279