Socioeconomic inequalities in the association between secondhand smoke exposure and tooth loss in Brazil

ObjectiveTo determine if (a) secondhand smoke (SHS) exposure is associated with tooth loss and (b) such a relationship is modified by socioeconomic position (SEP).MethodsData were from the 2019 Brazilian National Health Survey. Zero-inflated negative binomial regression and binary logistic regression were employed to examine the association between monthly exposure to SHS at home or at work with extent of teeth lost and lack of functional dentition (FD), respectively. Effect Measure Modification (EMM) analyses and the simple slope test explored whether the association varied with levels of education, wealth, and income.ResultsThe sample comprised 53,295 never smoker adults. Those exposed to SHS had 4% (95% CI: 1.01; 1.07) more lost teeth, were 19% (95% CI: 0.72; 0.92) more likely to have lost teeth, and were 25% (95% CI: 1.06; 1.47) more likely to lack a FD. A super-additive association was found when comparing participants exposed to SHS with incomplete elementary school and those unexposed to SHS with complete higher education (relative excess risk due to interaction of 0.97 [95% CI: 0.45; 1.49]). Such an EMM was less noticeable when examining other SEP measures.ConclusionSHS exposure was consistently associated with tooth loss; however, there appear to be key differences according to education levels.