Study protocol: Worldwide comparison of vitamin D status of immigrants from different ethnic origins and native-born populations-a systematic review and meta-analysis

Syst Rev. 2019 Aug 22;8(1):211. doi: 10.1186/s13643-019-1123-4.


Background: A growing body of literature indicates that, worldwide, immigrants experience health deterioration after their arrival into their adopted country, and moreover, they have lower vitamin D compared to the native-born population. We plan to review if the levels of vitamin D are comparable between different ethnic groups in different regions of the world with those of native-born populations and to identify the possible associations between vitamin D deficiency and disease status among immigrants.

Methods/design: A systematic review and meta-analysis will be conducted following the methods of the Cochrane handbook for systematic reviews. A literature search was performed to identify studies on immigrants and vitamin D. The primary outcome is vitamin D levels, and the secondary outcome is any vitamin D deficiency-related disease. Study design and participant characteristics will be extracted, including ethnicity, country of birth and/or origin, and the host country. Descriptive and meta-analytic summaries of the outcomes will be derived. Distiller-SR and RevMan will be used respectively for data management and meta-analysis.

Discussion: This systematic review may partially help clarify vitamin D-related health deterioration in migrants; moreover, to develop a global guideline that specifies sub-populations, in which the evidence and vitamin D-related recommendations might differ from the overall immigrant population.

Systematic review registration: PROSPERO CRD42018086729.

Keywords: Immigrants’ health deterioration; Meta-analysis; Systematic review; Vitamin D.

MeSH terms

  • Clinical Protocols
  • Emigrants and Immigrants*
  • Emigration and Immigration*
  • Global Health* / statistics & numerical data
  • Health Status
  • Health Status Disparities*
  • Humans
  • Meta-Analysis as Topic
  • Risk Factors
  • Systematic Reviews as Topic
  • Vitamin D Deficiency* / ethnology
  • Vitamin D Deficiency* / etiology