Differential effect of social mobility on tooth loss by race in adulthood: 1982 Pelotas Birth Cohort Study

To examine the association between social mobility and tooth loss in adults from the 1982 Pelotas Birth Cohort Study and whether race modifies this association.

The Oral Health Study used data from 541 individuals who were followed up to 31 years of age. Social mobility, composed of the participants' socioeconomic position (SEP) at birth and at age 30, was categorized as never poor, upwardly mobile, downwardly mobile and always poor. The outcome was the prevalence of at least one tooth lost due to dental caries when the participants were examined at 31 years of age. The effect modifier was race (Black/Brown versus white people). Log-binomial regression models were used to estimate crude and sex-adjusted prevalence ratios (PR) and to determine whether the association varied with race. Statistical interactions were tested using an additive scale.

The prevalence of any tooth loss was 50.8% (n = 274). In social mobility groups, the prevalence of at least one tooth lost in the never-poor group was about 31% points higher for Black/Brown (68.2%) than for white people (37.4%). Antagonistic findings were found for the interaction between race and social mobility (Sinergy Index = 0.48; 95% CI 0.24, 0.99; and relative excess of risk due to the interaction = -1.38; 95% CI -2.34, -0.42), suggesting that the observed joint effect of race and social mobility on tooth loss was lower than the expected sum of these factors. The estimates for Black/Brown people were smaller for those who were always poor during their lives, relative to their white counterparts.

The findings suggest a higher prevalence of at least one tooth lost among people in the downward mobile SEP group and Black/Brown people. Greater racial inequity was found among Black/Brown people who had never experienced episodes of poverty, with Black/Brown people having a greater prevalence of at least one tooth lost than their white counterparts.