Meta-analysis: longitudinal studies of serum vitamin D and colorectal cancer risk

Aliment Pharmacol Ther. 2009 Jul 1;30(2):113-25. doi: 10.1111/j.1365-2036.2009.04022.x. Epub 2009 Apr 15.


Background: In 1980, Garland hypothesized that lower levels of vitamin D resulting from much weaker UV-B radiation at higher latitudes may account for the striking geographical pattern of cancer mortality. Further research has been conducted over the past 20 years.

Aim: To perform a systematic review and meta-analysis of longitudinal studies on the association between serum 25 hydroxyvitamin D (25(OH)D) and the risk of colorectal cancer (CRC).

Methods: Relevant studies published until September 2008 were identified by systematically searching Ovid Medline, EMBASE, and ISI Web of Knowledge databases and by cross-referencing. Due to the heterogeneity of studies in categorizing serum vitamin D levels, all results were recalculated for an increase of serum 25(OH)D by 20 ng/mL. Summary odds ratios (ORs) were calculated using meta-analysis methods.

Results: Overall, eight original articles reporting on the association between serum 25(OH) D and CRC risk were included. In meta-analyses, summary ORs (95% confidence intervals) for the incidence of CRC, colon cancer and rectal cancer associated with an increase of 25(OH)D by 20 ng/mL were 0.57 (0.43-0.76), 0.78 (0.54-1.13) and 0.41 (0.11-1.49). No indication for publication bias was found.

Conclusions: Our results support suggestions that serum 25(OH)D is inversely related to CRC risk.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Clinical Trials as Topic
  • Colorectal Neoplasms* / blood
  • Colorectal Neoplasms* / epidemiology
  • Colorectal Neoplasms* / mortality
  • Epidemiologic Methods
  • Female
  • Humans
  • Male
  • Risk Factors
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood*


  • Vitamin D
  • 25-hydroxyvitamin D