Are overweight/obese children at risk of traumatic dental injuries? A meta-analysis of observational studies

Background/aim: Observational studies which investigated the association between overweight/obesity and traumatic dental injuries (TDI) reported contrasting results. Thus, this meta-analysis was designed to investigate such an association with the highest possible levels of internal and external validities.

Material and methods: A comprehensive literature search was performed through PubMed, ISI Web of Science, Cochrane Library, Scopus, Google scholar to ensure generalizability. Eligible studies reported clear case and control definitions, exposure assessment. Where possible, odds ratio (OR) adjusted for covariates was extracted. Study quality was assessed through Newcastle-Ottawa Scale (NOS). Only fair-to-good quality studies with NOS scores ≥4 were selected. The method to assess the pooled OR was based on the level of between-study heterogeneity, estimated through the Cochran's Q. Reliability of the pooled OR was improved by controlling for publication bias, sensitivity analysis to study inclusion, and subgroup analyses according to tooth type (permanent vs primary teeth) and country where the study was performed (Brazilian studies vs studies from other countries).

Results: Seventeen studies were selected from America, Asia, and Europe, their NOS scores ranged between 4 and 8. Overall, there were almost 28,000 patients, 7400 of them with TDI. The level of publication bias was minimal, and no adjustment was necessary. Between-study heterogeneity was high, and the random-effects method was used to assess the pooled OR, which resulted 1.30 (95% confidence interval, 1.11-1.53; P < 0.05). Sensitivity and subgroup analyses corroborated this estimate.

Conclusion: The choice to increase internal and external validity levels decreased the precision of the pooled OR (i.e., confidence intervals were relatively wide). The statistically significant overweight/obesity-TDI association, together with the so-called counterfactual condition (i.e., TDI prevalence was higher among overweight/obese children than among lean children), suggests that causal association between these two conditions is plausible.