Home ownership, income and oral health of children in Australia–a population-based study

Abstract

Objective: Income inequalities in children's oral health have been well described. It is plausible that the security of tenure reflected by the ownership status of children's housing dynamically interacts with household income to shape these inequalities. We examined whether housing tenure modifies the known association between household income and oral health. Methods: Data were analysed on 3344 10- to 11-year-old children from the Longitudinal Study of Australian Children. Multivariable regression models tested associations between household income and dental caries and tooth loss due to caries. Effect modification by home ownership (yes/no) was tested on the additive and multiplicative scales. Models were adjusted for sex, Indigenous status, main language spoken at home, area of residence, main carer education and family arrangement. Results: Children in households in the low income group had worse oral health than children in the high group for caries and tooth loss. Models only weakly supported an additive interaction for tooth loss; that is, the relative excess risk due to interaction (RERI) for low household income was -0.903 (-2.38; 0.571) for tooth loss and -0.076 (-0.42; 0.271) for dental decay, although we note that the low proportion of children from low-income homeowning households (6%) reduces the power to detect interactions. Notably, our models suggest renters in both high- and low-income categories had the highest risk of tooth loss compared to owners (PR for high-income renters: 2.19 (95% CI: 1.25, 3.85); PR for low-income renters: 2.11 (95% CI: 1.42, 3.16)). Conclusion: Our study confirms that children in low-income households have poorer oral health outcomes than their high-income counterparts. Our findings additionally suggest that children in rental households may fare the worst of all housing and income combinations considered. Improving the security of housing for families privately renting may have wider health benefits that currently acknowledged.