Supplementary Material for: Socio-environmental typologies and incidence of dental caries from childhood to adolescence among youth in Montreal: The QUALITY Cohort

Introduction: Leveraging data from a cohort study of Quebec youth with a family history of obesity, this study aimed to (i) identify neighbourhood socio-environmental typologies in childhood and (ii) estimate their associations with the incidence of dental caries in adolescence. Methods: We used baseline (2005-2008) and second follow-up (2012-2015) data from the ongoing QUALITY Cohort study in Montreal, Canada, which included 512 children aged 8-10 years with ≥1 biological parent with obesity at baseline. Based on prior literature and data availability, we selected three key neighbourhood-level indicators–social disorder, social deprivation, and material deprivation–measured in both school and residential settings. Latent class analysis was used to derive the socio-environmental typologies by combining social disorder, social deprivation, and material deprivation of the social environment in school and residential neighbourhoods. The outcome was dental caries incidence, assessed as the change in the Decayed, Missing, Filled-Surface index. Negative binomial regression was performed to estimate incidence ratios (IRs) and corresponding 95% confidence intervals (CIs). Results: Only three neighbourhood socioenvironmental typologies were identified. Type 1 neighbourhoods: high social disorder, high social deprivation, and low material deprivation; Type 2 neighbourhoods: median social disorder, median social deprivation, and median material deprivation; Type 3 neighbourhoods: low social disorder, low social deprivation, and high material deprivation. Compared to Type 1, the IRs (95% CIs) were 0.9 (0.6-1.2) for Type 2 and 0.8 (0.6-1.1) for Type 3. Conclusion: Neighbourhoods with lower social disorder and social deprivation may offer a protective effect against dental caries in youth.