Oral health-related quality of life and related factors among residents in a disaster area of the Great East Japan Earthquake and giant tsunami

Background: Oral health is one of the most important issues for disaster survivors. The aim of this study was to determine post-disaster distribution of oral health-related quality of life (OHRQoL) and related factors in survivors of the Great East Japan Earthquake and Tsunami. Methods: Questionnaires to assess OHRQoL, psychological distress, disaster-related experiences, and current systemic-health and economic conditions were sent to survivors over 18 years of age living in Otsuchi, one of the most severely damaged municipalities. OHRQoL and psychological distress were assessed using the General Oral Health Assessment Index (GOHAI) and the Kessler Psychological Distress Scale (K6), Japanese version, respectively. Among 11,411 residents, 1,987 returned the questionnaire (response rate, 17.4 %) and received an oral examination to determine number of present teeth, dental caries status, and tooth-mobility grade, and to assess periodontal health using the Community Periodontal Index. Relationships between GOHAI and related factors were examined by nonparametric bivariate and multinomial logistic regression analyses using GOHAI cutoff points at the 25th and 50th national standard percentiles. Results: GOHAI scores were significantly lower in the 50-69-age group compared with other age groups in this study and compared with the national standard score. In bivariate analyses, all factors assessed in this study (i.e., sex, age, evacuation from home, interruption of dental treatment, lost or fractured dentures, self-rated systemic health, serious psychological distress (SPD), economic status, number of teeth, having decayed teeth, CPI code, and tooth mobility) were significantly associated with OHRQoL. Subsequent multinomial logistic regression analyses revealed that participants of upper-middle age, who had received dental treatment before the disaster, who had lost or fractured dentures, and who had clinical oral health problems were likely to show low levels of OHRQoL. In addition, perceived systemic health and SPD were also related with OHRQoL. Conclusions: OHRQoL of disaster survivors was associated with oral problems stemming from the disaster in addition to factors related to OHRQoL in ordinary times such as clinical oral status and perceived systemic health. Furthermore, SPD was also associated with OHRQoL, which suggests the disaster's great negative impact on both oral and mental health conditions.