Original paper

Cancer Causes & Control

, 22:1383

First online:

Retinol, vitamins A, C, and E and breast cancer risk: a meta-analysis and meta-regression

  • Hu FulanAffiliated withDepartment of Epidemiology, Public Health College, Harbin Medical University
  • , Jiang ChangxingAffiliated withCenter for Endemic Disease Control, Harbin Medical University
  • , Wang Yi BainaAffiliated withDepartment of Epidemiology, Public Health College, Harbin Medical University
  • , Zhang WencuiAffiliated withDepartment of Epidemiology, Public Health College, Harbin Medical University
  • , Lin ChunqingAffiliated withDepartment of Epidemiology, Public Health College, Harbin Medical University
  • , Wang FanAffiliated withDepartment of Epidemiology, Public Health College, Harbin Medical University
  • , Li DandanAffiliated withDepartment of Epidemiology, Public Health College, Harbin Medical University
  • , Sun DianjunAffiliated withCenter for Endemic Disease Control, Harbin Medical University
  • , Wang TongAffiliated withCenter for Endemic Disease Control, Harbin Medical University
    • , Pang DaAffiliated withDepartment of Breast Surgery, Third Affiliated Clinical Hospital of Harbin Medical University Email author 
    • , Zhao YashuangAffiliated withDepartment of Epidemiology, Public Health College, Harbin Medical University Email author 

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Abstract

Objective

To comprehensively summarize the associations between retinol, vitamins A, C, and E and breast cancer, and quantitatively estimate their dose–response relationships.

Methods

We searched PubMed, Embase, and Cochrane databases (from January 1982 to 15 March 2011) and the references of the relevant articles in English with sufficient information to estimate relative risk or odds ratio and the 95% confidence intervals, and comparable categories of vitamins. Two reviewers independently extracted data using a standardized form, with any discrepancy adjudicated by the third reviewer.

Results

Overall, 51 studies met the inclusion criteria. Comparing the highest with the lowest intake, total vitamin A intake reduced the breast cancer risk by 17% (pooled OR = 0.83, 95% CI: 0.78–0.88). Further subgroup analysis based on study design did not change the significant reduction. Although the dietary vitamin A, dietary vitamin E, and total vitamin E intake all reduced breast cancer risk significantly when data from all studies were pooled, the results became nonsignificant when data from cohort studies were pooled. The significant association between total retinol intake and breast cancer in all studies became nonsignificant in case–control studies but remain significant in cohort studies. No significant dose–response relationship was observed in the higher intake of these vitamins with reduced breast cancer risk.

Conclusions

Our results indicate that both the total intake of vitamin A and retinol could reduce breast cancer risk. However, associations between other vitamins and breast cancer seem to be limited.

Keywords

Retinol Vitamin A Vitamin C Vitamin E Breast cancer Meta-analysis