Epidemiologic Research on Malformations Associated with Cleft Lip and Cleft Palate in Japan

To investigate malformations associated with cleft lip and cleft palate, we conducted surveys at neonatal intensive care units (NICUs) and other non-NICU facilities and to determine whether there are differences among facilities. The regional survey investigated NICU facilities located in Oita Prefecture, including 92 patients with cleft lip and palate (CLP) or cleft palate (CP) that occurred between 2004 and 2013, and the national survey investigated oral surgery, plastic surgery, and obstetrics and gynecology facilities located in Japan, including 16,452 patients with cleft lip (CL), CLP, or CP that occurred since 2000. The incidence per 10,000 births was 4.2, 6.2, and 2.8 for CL, CLP, and CP, respectively, according to the national survey, and 6.3 and 2.9 for CLP and CP, respectively according to the regional survey. These results indicated comparable incidences between the two surveys. In contrast, when the survey results on malformations associated with CLP and CP according to the ICD-10 classification were compared between the national survey conducted at oral surgery or plastic surgery facilities and the regional survey conducted at NICU facilities, the occurrence of associated malformations was 19.8% vs. 41.3% for any types of associated malformation, 6.8% vs. 21.7% for congenital heart disease, and 0.5% vs. 16.3% for chromosomal abnormalities. These results indicated that the incidences of all of these associated malformations were significantly greater in the survey conducted at NICU facilities and similar to the findings from international epidemiological surveys. When comparing the survey conducted at obstetrics facilities vs. NICU facilities, the occurrence of associated malformations was similar results as above. The incidence of CLP and CP was not different between surveys conducted at NICU facilities vs. non-NICU facilities; however, when conducting surveys on associated malformations, it is possible to obtain accurate epidemiological data by investigating NICU facilities where detailed examinations are thoroughly performed.