Association of Modifiable Risk Factors With Dental Caries Among Indigenous and Nonindigenous Children in Australia

IMPORTANCE: Although the prevalence of untreated dental caries among Indigenous Australian children greatly exceeds the prevalence observed among non-Indigenous children, the associations of dental caries with risk factors is considered to be the same. OBJECTIVE: To estimate the association of modifiable risk factors with area-based inequalities in untreated dental caries among Indigenous and non-Indigenous Australian children using decomposition analysis. DESIGN, SETTING, PARTICIPANTS: Cross-sectional study using data from Australia’s National Child Oral Health Study 2012-2014, a nationally representative sample of both Indigenous and non-Indigenous children aged 5 to 14 years. Data analyses were completed in November 2018. MAIN OUTCOMES AND MEASURES: Outcomes were the mean number of decayed tooth surfaces in the primary dentition for children aged 5 to 10 years and mean number of decayed tooth surfaces in the permanent dentition for children aged 8 to 14 years. The area-based measure was the school-based Index of Community Socio-Educational Advantage, with individual-level variables including sex, equivalized household income, tooth-brushing frequency, sugar-sweetened beverage (SSB) consumption, time from last dental visit, and residing in an area with water fluoridation. RESULTS: There were 720 Indigenous children aged 5 to 10 years, 14 769 non-Indigenous children aged 5 to 10 years, 738 Indigenous children aged 8 to 14 years, and 15 631 non-Indigenous children aged 8 to 14 years. For area-based inequalities in primary dentition among Indigenous children, two-thirds of the contribution was associated with SSB consumption (65.9%; 95% CI, 65.5%-66.3%), followed by irregular tooth brushing (15.0%; 95% CI, 14.6%-15.5%) and low household income (14.5%; 95% CI, 14.1%-14.8%). Among non-Indigenous children, almost half the contribution was associated with low household income (47.6%; 95% CI, 47.6%-47.7%), followed by SSB consumption (31.0%; 95% CI, 30.9%-31.0%) and residing in an area with nonfluoridated water (9.5%; 95% CI, 9.5%-9.6%). For area-based inequalities in permanent dentition among Indigenous children, 40.0% (95% CI, 39.9%-40.1%) of the contribution was associated with residing in an area with nonfluoridated water, followed by low household income (20.0%; 95% CI, 19.7%-20.0%) and consumption of SSBs (20.0%; 95% CI, 19.9%-20.1%). Among non-Indigenous children, the contribution associated with low household income, SSB consumption, and last dental visit more than a year ago were each 28.6%. CONCLUSIONS AND RELEVANCE: The association of modifiable risk factors with area-based inequalities in untreated dental caries among Indigenous and non-Indigenous Australian children differed substantially. Targets to reduce SSB consumption may reduce oral health inequalities for both groups; however, Indigenous children require additional focus on oral hygiene.