Social inequities in general health and oral health among Australian adults over time

Social inequality in health is a persistent and growing concern worldwide. The study aimed to describe and analyse social disparities in general and oral health among Australian adults over time. This study utilised two population-based cross-sectional survey data: the National Survey of Adult Oral Health (NSAOH) conducted in 2004-06 (NSAOH-1, n = 14,123) and 2017-18 (NSAOH-2, n = 15,731) in Australia. Representative samples of adults aged 15 years and over were recruited from metropolitan and regional areas in each state and territory using a three-stage, stratified sampling design. Outcome variables were self-rated general and oral health conditions. Explanatory variables included socioeconomic status- assessed using equivalised household income and divided into roughly equal quartile groups from lowest to highest- along with sociodemographic characteristics, culturally and linguistically diverse status, and oral health-related behaviours. Both unadjusted and adjusted absolute prevalence differences (PDs) of fair/poor general and oral health with 95% confidence intervals were calculated to assess income-related inequality. Adjustments were made for age and sex to the average covariate distribution of the four household income groups combined. The prevalence of fair/poor general and oral health increased from 10.6% to 15.0% and from 16.4% to 23.9%, respectively, over the 14-year survey period. Across all household income quartiles, the prevalence of fair/poor general and oral health was higher in NSAOH-2 than in NSAOH-1. The adjusted model showed that the prevalence increase was most marked for the second lowest household income group (Q2), from 18.7% to 26.7% (PD = 8.0%) for oral health and the second highest household income group (Q3), from 6.4% to 10.8% (PD = 4.4%) for general health. Our study revealed social inequalities in general and oral health among Australian adults over 14 years, with age, sex, place of residence, irregular dental visits, and dental insurance being significant factors contributing to these inequities.