International Comparative Research of Oral Health Inequality between Japan and England
Socioeconomic inequalities have been reported to have effects on oral health. Our aim is to examine the association between income and oral health among older adults in England and Japan.
METHODS:
We used the data from the Japan Gerontological Evaluation Study (JAGES) and from the English Longitudinal Study of Ageing (ELSA), both collected during 2010 and 2011. Information obtained from the old adults aged 65 years or over was used for this study. Quartile equivalised income was used as an indicator for social gradients. Outcomes are edentulousness (zero remaining teeth), which obtained from the reported numbers of remaining teeth, and self-reported oral health status (SROH). Log-binomial regression model were applied to determine the independent association between income and outcomes (SROH and edentulousness) after controlling for the effects from sex , age and educational attainment of the participants in each country.
RESULTS:
Of 19,726 Japanese participants and 4,876 English participants, 15.0% and 20.9% were edentulous and very few felt that their SROH was poor in either country (JAGES=5.5%; ELSA=3.5%). In both Japan and England, lower income was significantly and independently associated with both higher risk of edentulousness and poorer SROH. Income gradient was appeared to be steeper in England than in Japan in both edentulousness (ELSA: PR=1.69, 95%CI=1.38, 2.07; JAGES: PR=1.37, 95%CI=1.28, 1.48) and SROH (ELSA: PR=2.46, 95%CI=1.27, 4.76; JAGES: PR=1.81, 95%CI=1.50, 2.19).
CONCLUSIONS:
Oral health of old adults is likely to be determined by their income in both Japan and England and the gradient appeared to be steeper in England than in Japan. Future international comparative studies should examine social gradient of dental care access and preventive service, which would explain this country difference in social gradients in oral health.