The prevalence of vitamin D deficiency among dark-skinned populations according to their stage of migration and region of birth : a meta-analysis

Objectives: The prevalence of vitamin D deficiency (VDD) varies among migrants from different geographic regions. The aim of this study was to estimate the pooled prevalence of VDD among dark-skinned migrants. Method: A meta-analysis using meta-regression was undertaken to determine the prevalence of VDD in dark-skinned migrant populations. Prevalence also was determined by study characteristics including study methodology, age of populations examined, and length of time in migrated country. Results: Thirty-six studies were identified in nonpregnant populations. Of 13 974 individuals in the studies, 9562 were vitamin D deficient. Pooled prevalence in dark-skinned migrants, adjusted for latitude of study country was estimated at 77% (95% confidence interval [CI], 70%-84%). Examination of studies in which migrants from both Sub-Saharan Africa and the extended Middle East were examined (N = 7) showed immigrants from the extended Middle East had a higher prevalence of VDD (65%; 95% CI, 45%-94%) compared with those from Sub-Saharan Africa (56%; 95% CI, 34%-77%). Seven studies were identified in pregnant dark-skinned migrant women. This group tended to have much higher prevalence of VDD compared with native-born pregnant women. Conclusion: Immigrants with dark skin, and in particular those from the extended Middle East region, have high prevalence of VDD. Migrants who are at high risk for VDD should be educated, screened, and monitored for VDD.