High prevalence of toothache among Great East Japan Earthquake survivors living in temporary housing.

Abstract

The Great East Japan Earthquake and subsequent tsunami cause large-scale destruction in the north-eastern coastal areas in Japan, and forced many survivors to relocate to prefabricated temporary housing, a typical emergency accommodation. Based on the hypothesis that higher toothache prevalence among the disaster survivors is associated with postdisaster distress, we determined the impact of temporary residential environment as potential stressor on the subjective toothache prevalence. A repeated cross-sectional health survey based on self-reported questionnaire was conducted in 2776 disaster survivors, of whom 1446 participants underwent dental examination by dentists. Housing type was categorized into three groups including the same housing as before the earthquake, temporary housing and rented/new housing. The association of housing type with subjective toothache prevalence was examined using multivariate logistic regression analysis in all subjects and subgroup analysis in dental examination applicants. Stratified analysis by survey wave was applied with inclusion of covariates such as the socio-demographic factors, and presence of insomnia and psychological distress. In subgroup analysis, presence of dental caries and gum problems in dental examination were included as factors of direct exposure to subjective toothache. In the first survey wave, the participants living in the temporary housing had significantly higher odds ratio (OR) for toothache prevalence compared to the participants living in the same housing (OR: 3.76, 95% confidence interval [CI]: 1.85-7.65, P<0.001); whereas in all other survey waves, there was no significant difference. Subgroup analysis of dental examination applicants confirmed the presence of significant association of subjective toothache prevalence in the temporary housing group alone (OR: 3.27, 95% CI: 1.38-7.76, P=0.004), but not in the rented/new housing group (OR: 1.50, 95% CI: 0.57-3.91, P=0.411), even after adjusting for covariates related to oral findings. Temporary housing may be a factor to increase the risk of subjective toothache among disaster survivors only at postdisaster acute phase.