The Correlation of Plasma 25-Hydroxyvitamin D Deficiency With Risk of Breast Neoplasms: A Systematic Review

CONTEXT Breast cancer has been considered as one of the most common types of cancer among the women worldwide, and patients with breast neoplasms have been reported with high prevalence of low serum 25-hydroxyvitamin D levels. OBJECTIVES Our aim was to evaluate the correlation of plasma 25-hydroxyvitamin D deficiency with breast neoplasms risk among women. DATA SOURCES PubMed database was searched with MeSH (medical subject headings) keywords "vitamin D AND breast neoplasms" which was restricted by original articles written only in English and published from January 1, 2014. STUDY SELECTION To find the articles that met eligibility criteria, titles and abstracts were examined. DATA EXTRACTION This systematic review was conducted according to PRISMA (preferred reporting items for systematic reviews and meta-analyses) statement. Critical appraising of evidence was performed, using the study quality assessment tools of national institutes of health, national heart, lung and blood institute (NHLBI). RESULTS Overall, 76 potential articles were identified and after screening, 13 articles met eligible criteria for inclusion. Definition of low vitamin D levels varied greatly among studies, making comparisons difficult, but most of them have defined deficiency as 25(OH)D < 20 ng/mL. Evidence was mainly of fair quality. CONCLUSIONS This study has provided evidence that vitamin D deficiency has been very prevalent in patients with breast neoplasms, more than comparable matched control population, and risk of breast cancer has increased with low vitamin D levels, suggesting the need for high quality studies that assessed the health consequences attributable to vitamin D deficiency employing standard definitions.