Lifecourse socioeconomic position indicators and tooth loss in Korean adults

The aim of this study was to assess the association between lifecourse socioeconomic position (SEP) indicators and tooth loss in a large representative sample of the Korean adult population.

Data from the Fourth and Fifth Korea National Health and Nutritional Examination Survey on 17,549 Korean adults aged 50 years or older were analyzed. The study design was cross-sectional. Tooth loss was defined as either edentulism (0 teeth) or severe tooth loss (<20 teeth). Parental education, own education, and income were used as indicators of early childhood SEP, adolescent SEP, and adulthood SEP, respectively. The association between the lifecourse SEPs and tooth loss was estimated with three different lifecourse models: the independent impact model for three different lifecourse SEPs, the cumulative impact model using the sum of the three SEP scores, and the social mobility model using the pathway information of the three SEPs. The covariates were demographic factors and health behaviors. The prevalence ratios (PRs), slope index of inequality (SII), and relative index of inequality (RII) for tooth loss were estimated with log-binomial regression analyses.

In the independent impact model, significant associations of each SEP with edentulism (SII=3.61%, 4.76%, 2.17% and RII=1.67, 1.52, 1.41 for parental education, own education, and income, respectively) and severe tooth loss (SII=8.03%, 17.73%, 12.73% and RII=1.26, 1.72, 1.42 for parental education, own education, and income, respectively) were found after adjusting for all covariates. For the cumulative impact model, stepwise patterns of PRs according to the summed SEP scores were found. In addition, in the social mobility model, the PR of tooth loss was greatest in the persistently low SEP group over the life course (PR=2.10 for edentulism and 2.33 for severe tooth loss). The other mobile groups in lifecourse SEPs also presented higher PRs of tooth loss than the persistently high SEP group.

Parental education was independently associated with edentulism in later life, and own education showed the strongest associations with tooth loss. The cumulative and social mobility models for the social impacts of life course on oral health should be considered in oral epidemiological studies.