title: Impact of vitamin D supplementation on the outcome of tuberculosis treatment: a systematic review and meta-analysis of randomized controlled trials.
abstract: BACKGROUND
  Vitamin D supplementation is believed to be beneficial in the treatment of patients with tuberculosis (TB), however, results from clinical trials have been inconclusive.
  
  
  METHODS
  We performed a systematic literature search across MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Springer, EBSCO, ProQuest, HighWire Press, and Web of Science, published as of December 2013. We individually inspected citations and extracted data independently. We estimated pooled risk ratios (RR) and 95% confidence intervals (CI) using random-effect models. We also assessed risk of bias using the Jadad scale and the quality of the evidence using GRADE. We included all randomized controlled trials comparing vitamin D with or without standard TB therapy or placebo.
  
  
  RESULTS
  A total of five studies were analyzed in our meta analysis covering 841 newly-diagnosed TB cases. Patients receiving vitamin D supplementation had a 39% reduced risk of sputum smear or culture positive after six weeks of anti-TB treatment than those in the control group, although this is not statistically significant (pooled RR 0.61, 95% CI 0.24 to 1.56, P = 0.30). Apart from an increased serum vitamin D level in the supplement group after eight weeks of treatment there was no evidence of any additional adverse effects related to vitamin D.
  
  
  CONCLUSIONS
  The meta analysis results indicate that vitamin D supplementation does not seem to have any beneficial effect in the treatment of TB. Future rigorous randomized controlled trials are needed to explore whether the supplementation of vitamin D could shorten treatment duration and to confirm whether the polymorphisms of vitamin D receptor have any potentially beneficial effect.
authors.affiliation: Department of Radiation Oncology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China.
authors.forename: Jingyan
authors.initials: J
authors.lastname: Xia
authors.affiliation: Division of Immunology, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China.
authors.forename: Liyun
authors.initials: L
authors.lastname: Shi
authors.affiliation: Department of Infectious Diseases, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China.
authors.forename: Lifang
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Infectious Diseases, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China. Email: xufeng99@yahoo.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
mesh_terms: D019587:Dietary Supplements; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D014376:Tuberculosis / Q000097:blood / Q000188:drug therapy*; D014807:Vitamin D / Q000097:blood / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D