Trends in Tooth Loss Prevalence by Income Level in the United States

Objectives: Income inequality has increased dramatically in the US over the past few decades. Considering the established association between income and health, this increasing income gap may provide insights into the dynamics of the oral disease burden in the US.
Methods: Cross-sectional analyses were performed using the National Health and Nutrition Examination Survey (NHANES) database from 1999 to 2018 containing information of 12481 people aged 60-80. Two survey-weighted logistic regression models were used to analyze unadjusted (model 1) and age, sex, race, education, obesity, and insurance adjusted (model 2) prevalence trend of tooth loss for participants between different income levels.
Results: The prevalence of tooth loss no significantly declined in the highest-resources group (the richest 20% of the population) during the study period (1999-2018): edentulous from 4.24% to 2.2% (P=0.43 for trend), severe tooth loss from 10.14% to 5.88% (P=0.36 for trend), and lack of function dentition from 28.07% to 16.76% (P=0.106 for trend). In the remainder of the population, the prevalence of edentulous significantly declined from 27.78% in 1999 to 14.79% in 2018 (P<0.001 for trend), as did severe tooth loss from 41.57% to 21.06% (P<0.001 for trend), and lack of function dentition from 64.29% to 40.57% (P<0.001 for trend). Adjusted for age, sex, race, education, obesity and insurance, tooth loss prevalence trend showed similar results.
Conclusions: This study found substantial and decreasing disparities in tooth loss prevalence between the richest and poorest participants in the NHANES from 1999 to 2018. The trend of tooth loss was stable with no significant reduction for the richest 20% of participants but decreased remarkably in the remainder of the population.