Prevalence and risk factors of molar incisor hypomineralization in the Middle East: A systematic review and meta-analysis

Objectives: Molar incisor hypomineralization (MIH) is a growing global concern. Herein, we conducted a sys-tematic review and meta-analysis of the prevalence and associated factors/risk factors of MIH in the Middle East (ME).Methods: This systematic review and meta-analysis included studies on children with at least one first per-manent molar affected by MIH, aged 5-18 years, without syndromes or congenital anomalies, and residing in the ME and included cross-sectional, case-control, and cohort studies. Keywords related to MIH and ME countries were systematically searched until January 10, 2021 in four databases, PubMed, Google Scholar, Science Direct, and the Cochrane Library, following the specified eligibility criteria. The Joanna Briggs Institute quality assessment tool was used to evaluate all included studies. Meta-analyses were conducted to assess the effect of risk factors. The study protocol was registered on the PROSPERO International Prospective Register of Sys-tematic Reviews (Registration No. 247391).Results: After screening 4,373 documents, 29 eligible studies with a total of 32,636 children aged 7-12 years were included from 11 countries. The frequency of MIH reported in the ME ranged from 2.3% to 40.7%, with a mean prevalence of 15.05%. Pregnancy and early child-hood illnesses (odds ratio [OR]: 2.26, 95% confidence interval [CI]: 1.91-2.68; P < 0.001) and factors related to delivery (OR: 2.4, 95% CI: 1.55-3.72; P < 0.001) were statically significantly associated with MIH.Conclusion: The mean prevalence of MIH in ME aligns with the global MIH prevalence rate. Illnesses and de-livery complications are risk factors that could be controlled to prevent MIH. As included studies showed high heterogeneity in the meta-analyses, further evidence from the ME is needed to assess the prevalence and other associated environmental risk factors for MIH.