Oral health inequities over time among older adults of different racial/ethnic backgrounds: a comparative decomposition analysis across Australia and the United States.

Background: Although the prevalence of poor oral health among older populations in Australia and the United States is higher, the contribution of ethnicity status is unknown. We aimed to estimate the contribution of social inequalities in oral health among older populations in Australia and the United States.

Methods: Cross-sectional study design using data from Australia's National Survey of Adult Oral Health (NSAOH 2004-06 and 2017-18) and the United States' National Health and Nutrition Examination Survey (NHANES 2003-04 and 2011-16). Participants included in the analysis were aged 65 + years. Oaxaca-Blinder type decomposition analysis was used to assess the contribution of demographic (age, sex), socioeconomic position (educational attainment, household income) and dental behaviors (last dental visit) to changes in prevalence of edentulism and non-functional dentition, and mean number of missing teeth by ethnicity status over time in Australia and the United States.

Results: The number of participants aged 65 + years who provided clinical and sociodemographic/dental behaviour data was 1043 and 1269 in NSAOH 2004-06 and 2017-18, and 1372 and 1328 in NHANES 2003-04 and 2011-16 respectively. The prevalence of edentulism was from 13 percent (NHANES 2011-16) to 28 percent (NSAOH 2004-06), while the prevalence of non-functional dentition was from 41 percent (NSAOH 2017-18 and NHANES 2011-16) to 61 percent (NHANES 2003-04). The mean number of missing teeth was from 11 (NSAOH 2017-18) to 18 (NHANES 2003-04). The prevalence of edentulism and non-functional dentition, and the mean number of missing teeth were higher among older Australians identifying as White and the opposite results were observed among older Americans identifying as Non-White. For older adults in Australia, risk factors with the greatest impact on oral health outcomes by ethnicity status were educational attainment and household income. For older adults in the United States, the most dominant risk factor for non-optimal oral health outcomes by ethnicity status was last dental visit.

Conclusions: There are important policy translation implications from our findings, as they indicate that social and structural systems in Australia and the United States operate differently in the context of oral health over time among culturally diverse older citizens. This information will help inform initiatives that both target effective oral health promotion for older, culturally-diverse populations and provide evidence for the distribution of resources in the public dental health setting for this age group and cultural demographic.