Socioeconomic and racial disparities in edentulism among US adults: Age, period & cohort models

OBJECTIVE: To study temporal trends and the changing social conditions contributing to socioeconomic and racial disparities in edentulism for adults over time. METHODS: A social demography Age-Period-Cohort (APC) approach was employed to analyze edentulism trends for Blacks and Whites using data from 1982-2010 from the National Health Interview Survey (NHIS) and from the National Health and Nutrition Examination Survey (NHANES III (1988-1994) through 2007-2008). Cross-classified random effects models were specified to directly model age, nesting individuals into their appropriate interview year (period) and birth year (cohort). A baseline, age-only model was explored first. Age, period, cohort, demographic (education, marital status, employment, income, household size, region) and health behavior (smoking, drinking) variables were included in the adjusted model. Period and cohort trends were estimated, by race and gender. RESULTS: Preliminary NHIS results from adjusted models indicated flat period trends, with white women having the highest predicted probabilities for edentulism, and black men the lowest. The baseline cohort model showed edentulism declining steadily across cohorts. Black women had higher probabilities of edentulism across all cohorts through the 1950 cohort. White women and men had lower trends across cohorts, converging with black women around 1950. In the adjusted model, black men's probabilities were reduced somewhat across cohorts. In contrast, trends for white men became similar to those of black women, even among earlier cohorts; most dramatically white women had the highest probabilities across all cohorts. Similar trends were found in NHANES. CONCLUSION: Edentulism declines happened across cohorts, net of aging and period effects.