December 2017

Objectives: Socioeconomic position (SEP) is inversely associated with most oral health outcomes, but the patterns of association may vary depending on the specific outcome. We estimated associations between SEP and two oral health outcomes, dental caries and traumatic dental injuries (TDI), in Quebec children. Methods: We used data from the baseline visit of the QUALITY (QUebec Adipose and Lifestyle Investigation in Youth) Cohort, an ongoing study in Montreal and Quebec, Canada. The analytical sample included 590 children aged 8-10 years. Data on parents’ SEP (household income, education) and children’s health behaviours and involvement in sports were obtained through questionnaires and interviews. Oral health outcomes (dental caries and TDI in permanent teeth) were assessed by clinical oral exam. Negative binomial regression was used to model dental caries (DMFS index) and number of teeth with TDI adjusting for selected covariates. Results: The mean (SD) DMFS and number of TDI were 0.61 (1.43) and 0.12 (0.43), respectively. Compared to the upper quartile of income, children in the lower quartile had a DMFS approximately 3 times higher (PRR=2.68, 95% CI: 1.43, 5.04). Adjusting for oral health and nutritional behaviours had no effect. Conversely, children in the highest income quartile had a 3 times higher number of teeth with TDI compared to the lowest quartile (PRR=3.14, 95% CI: 1.22, 8.08). Physical activity did not explain this relationship. Parents’ education was not associated with dental caries or TDI. Conclusion: SEP seems to play a different role in the cause of dental caries and TDI. Key words: Dental caries; traumatic dental injury; inequality; child; epidemiology; socioeconomic factors, Canada