Review: the impacts of circulating 25-hydroxyvitamin D levels on cancer patient outcomes: a systematic review and meta-analysis.
BACKGROUND
Circulating levels of 25-hydroxyvitamin D [25(OH)D] may affect the prognosis of cancer patients; however, the epidemiological results are not consistent.


OBJECTIVE
To perform a meta-analysis of all published studies to assess the associations of circulating 25(OH)D levels measured at or near the time of diagnosis and outcomes for cancer patients.


METHODS
Searches of the PubMed and MEDLINE databases were performed and updated to December 2013.


METHODS
Studies reporting an association between circulating 25(OH)D levels at or near the time of diagnosis and outcomes for the patients were included.


METHODS
Data extraction was performed independently by two authors, and conflicts were resolved by a third investigator.


RESULTS
Included in the meta-analysis were 25 studies with 17 332 cases. Significant associations between circulating 25(OH)D levels at or near the time of diagnosis and the outcomes for cancer patients were found. The pooled hazard ratio for the highest vs the lowest quartile of circulating 25(OH)D levels was 0.55 (95% confidence interval [CI] = 0.33-0.91) for overall survival of colorectal cancer patients, 0.63 (95% CI = 0.51-0.77) for breast cancer patients, and 0.48 (95% CI = 0.36-0.64) for lymphoma patients. Higher 25(OH)D levels were significantly associated with reduced cancer-specific mortality for patients with colorectal cancer (P = .005) and lymphoma (P < .001) and improved disease-free survival for patients with breast cancer (P < .001) or lymphoma (P < .05). A 10-nmol/L increment in circulating 25(OH)D levels conferred a hazard ratio of 0.96 (95% CI = 0.95-0.97) for overall survival of the cancer patients.


CONCLUSIONS
The results indicate that cancer patients with higher circulating 25(OH)D levels at or near the time of diagnosis have better outcomes.
Key Laboratory of Food Safety Research (M.L., P.C., J.L., R.C., D.X., H.W.), Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai 200031, China; Key Laboratory of Food Safety Risk Assessment (D.X., H.W.), Ministry of Health, Beijing 100021, China; and School of Life Science and Technology (D.X., H.W.), Shanghai Tech University, Shanghai, 200031, China.
Mian
M
Li
Peizhan
P
Chen
Jingquan
J
Li
Ruiai
R
Chu
Dong
D
Xie
Hui
H
Wang
D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000401:mortality; D011379:Prognosis; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D014807:Vitamin D; C104450:25-hydroxyvitamin D