The Birth Prevalence of Cleft Lip and/or Cleft Palate After the 2011 Tōhoku Earthquake and Tsunami.

OBJECTIVE

This study examined whether the 2011 Tōhoku earthquake and tsunami affected the birth prevalence of cleft lip and/or cleft palate (CL/P) in Miyagi Prefecture, where the earthquake and tsunami caused severe damage.

DESIGN

This was a retrospective cohort study.

SETTING

The study was conducted at university and children's hospitals in Miyagi Prefecture.

PARTICIPANTS

The annual and monthly numbers of infants born with CL/P were obtained from medical records. The affected period of birth was defined as 1 year from December 1, 2011, to November 30, 2012. The control period was 5 years from January 1, 2006, to December 31, 2010. The annual and monthly numbers of births in Miyagi Prefecture were obtained using e-Stat, which is a portal for Japanese government statistics.

MAIN OUTCOME MEASURES: Main outcome measures were birth prevalence of CL/P during the control and affected periods.

RESULTS

There were no significant differences between the control and affected periods in the prevalence (per 10 000 live births) of cleft lip with or without palate (13.8 vs 16.7; P = .342), isolated cleft palate (5.2 vs 3.2; P = .267), or overall CL/P (19.0 vs 19.9; P = .799).

CONCLUSIONS

We did not observe that the 2011 Tōhoku earthquake and tsunami affected the birth prevalence of CL/P in Miyagi Prefecture, even though it severely impacted human health in the area.