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@ARTICLE{Schttker:166805,
      author       = {B. Schöttker$^*$ and S. Kuznia$^*$ and H. Brenner$^*$},
      title        = {{E}fficacy of vitamin {D}3 supplementation on cancer
                      mortality in the general population and the prognosis of
                      patients with cancer: protocol of a systematic review and
                      individual patient data meta-analysis of randomised
                      controlled trials.},
      journal      = {BMJ open},
      volume       = {11},
      number       = {1},
      issn         = {2044-6055},
      address      = {London},
      publisher    = {BMJ Publishing Group},
      reportid     = {DKFZ-2021-00135},
      pages        = {e041607},
      year         = {2021},
      note         = {#EA:C070#LA:C070# / Protocol},
      abstract     = {Vitamin D insufficiency is much more common among patients
                      with cancer than the general population. Previous
                      meta-analyses of controlled trials showed an approximately
                      $15\%$ reduction of cancer mortality by vitamin D
                      supplementation compared with placebo or no treatment in the
                      general population.On top of updating the latest systematic
                      review on vitamin D supplementation and cancer mortality in
                      the general population, we aim to conduct the first
                      meta-analyses of trials on vitamin D3 supplementation and
                      cancer-specific and overall survival of patients with
                      cancer. Besides, we will conduct for the first time subgroup
                      analyses based on individual patient data collected from
                      randomised controlled trials.A systematic review and
                      individual patient data meta-analysis will be performed on
                      randomised placebo-controlled trials with a vitamin D3
                      intervention. All databases are searched from inception
                      without time restriction. The addressed outcomes are cancer
                      mortality in the general population as well as
                      cancer-specific and overall survival of patients with
                      cancer. The quality appraisal of the studies will be
                      evaluated by the Cochrane risk-of-bias tool for randomised
                      trials. Trial results will be reanalysed using adjusted and
                      unadjusted Cox proportional hazard regression models and
                      meta-analyses are planned. Cochran's Q-Test and the I2 index
                      will be used to statistically assess the level of
                      heterogeneity, while sensitivity and subgroup analyses serve
                      to identify potential causes of heterogeneity. Subgroup
                      analyses will be conducted for vitamin D3 dosing, follow-up
                      time, age, sex, obesity, vitamin D deficiency/insufficiency,
                      history of cancer and compliance. Publication bias will be
                      assessed by funnel plots and Egger's test.Ethical approval
                      is not required since no human beings are involved in this
                      systematic review. Results will be published in a
                      peer-reviewed journal with open access. They will be
                      presented at conferences and sent to patient advocacy groups
                      and German oncological rehabilitation
                      centres.CRD42020185566.},
      keywords     = {epidemiology (Other) / nutrition $\&$ dietetics (Other) /
                      nutritional support (Other) / oncology (Other) / protocols
                      $\&$ guidelines (Other) / public health (Other)},
      cin          = {HD01 / C070 / C120},
      ddc          = {610},
      cid          = {I:(DE-He78)HD01-20160331 / I:(DE-He78)C070-20160331 /
                      I:(DE-He78)C120-20160331},
      pnm          = {313 - Krebsrisikofaktoren und Prävention (POF4-313)},
      pid          = {G:(DE-HGF)POF4-313},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:33441357},
      doi          = {10.1136/bmjopen-2020-041607},
      url          = {https://inrepo02.dkfz.de/record/166805},
}