Bidirectional association between dental caries and body mass index in socially vulnerable adolescents: a group-based...

To examine bidirectional associations between dental caries and body mass index (BMI) among adolescents living in vulnerable communities in Brazil.

In a cohort study involving adolescents (n = 323), BMI, number of decayed teeth and odontogenic infections (PUFA/pufa index) were recorded at three time points between 12 and 15 years of age. Trajectories of dental caries, odontogenic infections, and BMI were developed using group-based trajectory modelling. Associations between dental caries and odontogenic infections trajectories with changes in BMI z-scores, and between BMI trajectories and dental caries and odontogenic infections incidence were adjusted for sugar intake and socioeconomic conditions using multiple Poisson regression.

Three distinct trajectories of dental caries (stable low, moderate increasing, and high increase), odontogenic infections (stable low, stable moderate, and stable high), and BMI z-scores (stable low, stable moderate, and stable high) were identified. Compared with the stable moderate BMI z-score trajectory, the stable low was associated with increased risk of dental caries incidence (IRR 1.48, 95%CI 1.05-2.09). The high increase dental caries trajectory (IRR 1.38, 95%CI 1.02-1.88) and high stable odontogenic infections trajectory (IRR 1.50, 95%CI 1.12-2.00) were associated with positive changes in BMI z-scores.

Adolescents living in deprived communities with persistently low BMI were at higher risk of dental caries. Those with increasing dental caries and consistently high levels of odontogenic infections were at higher risk of BMI z-scores increases. Effective individual and public health strategies to reduce dental caries and malnutrition in adolescents should be aligned.

Dental caries and body mass index are interrelated in underprivileged adolescents.