The prevalence, risk of premature births, mortality and causes of death of cleft lip with or without palate in South Korea: a nationwide population-based cohort study

Background: Very few recent nationwide studies have assessed the epidemiology of cleft lip with or without palate (CL/P). The purpose of this study was to identify the prevalence, risk of premature births, mortality and cause of death of CL/P. Methods: This nationwide population-based cohort study evaluated all 5 747 830 live births in South Korea, including CL/P infants, from 2006 to 2018. The prevalence with trend analysis, risk of premature births, mortality and cause of death of CL/P with or without associated syndromes (non-syndromic, syndromic CL/P) and subgroups (cleft lip only, cleft palate only, cleft lip with palate) were evaluated. Results: Among 5 747 830 live births, 11 284 children were identified as having CL/P during the study period. The annual prevalence was 1.96 per 1000 births. The prevalence ratio, which shows the trend during the period, was 1.021. Both non-syndromic and syndromic CL/P children had higher risk of premature births compared with children without CL/P (odds ratio: non-syndromic 1.43, syndromic 5.29). The mortality rates per 1000 person-years were 0.39 for children without CL/P, 0.98 for non-syndromic CL/P children and 12.20 for syndromic CL/P children. The causes of deaths were not different for children without CL/P in non-syndromic CL/P, but the most common cause of deaths was cardiovascular anomalies in syndromic CL/P. Conclusion: The reported prevalence of 1.96 per 1000 births is one of the highest prevalences worldwide. CL/P children had high risks of premature births and risk of mortality. The most common cause of deaths was cardiovascular anomalies.