Affluent Neighborhoods Protect Tooth Retention among Adults with Low Income

Objectives: To determine if the degree of inequality in tooth retention associated with individuals' socioeconomic position is modified by the affluence of the neighborhood in which people live. We tested the hypothesis that, in affluent neighborhoods, the gradient between individual income and tooth retention would be attenuated compared the gradient observed in poor neighborhoods.

Methods: In 2003, the cross-sectional Adelaide Small Area Dental Study collected sociodemographic and tooth retention information with a self-administered questionnaire mailed to 2,860 middle-aged adults (level 1) nested in 60 neighborhoods (level 2). The socioeconomic position of individuals was evaluated using educational attainment and level of household income. Neighborhood socioeconomic position was evaluated using a census-based composite measure of area disadvantage. Covariates were sex and age, centred at its mean value. Using multilevel modelling we fitted a series of two-level random intercept variance components models with parameters estimated from the iterative generalized least squares method in MLwiN version 2.0.

Results: Findings revealed significant main effects for level 1 and level 2 predictors and a statistically significant cross-level interaction (P=0.005), between individual-level and neighborhood-level socioeconomic position. In poor neighborhoods, people in lowest income households had retained an adjusted mean of 21.7 teeth per person compared with 26.0 teeth for people in highest income households – a difference of 4.3 teeth per person that was statistically significant.

Conclusion: Individuals' socioeconomic position had a negligible influence on tooth retention in affluent neighborhoods but a substantial influence in poor neighborhoods. Low-income adults appeared to benefit from affluent areas, suggesting that community resources, and not just individual behaviours, are important determinants of oral health. . The National Health and Medical Research Council (NHMRC) funded this study and Dr Sanders is supported by a NHMRC Sidney Sax Public Health Fellowship.