Effect of BMI on Caries Assessed by Structural Equation Modelling in an Adult Brazilian Population

Compare different behavioural, environmental and socioeconomic factors for caries with transversal data to decompose the direct and indirect effects of body mass index (BMI) in relation to coronal and root caries.

This cross-sectional study used a representative sample of 1002 individuals aged ≥ 35 years living in Porto Alegre. Questionnaires recorded age, sex, educational level, tooth brushing frequency and access to dental services. Oral examination assessed gingival bleeding and recession, coronal and root caries. Height and weight were collected to calculate the BMI. The structural equation modelling approach was used, and standardised coefficients (SC) to direct, indirect and total effects were calculated.

The prevalence of excessive body weight was 71.17%, of which 40.09% were overweight and 31.07% were obese. The overall prevalence of coronal and root caries was 99.83 and 36.95, respectively. No direct link between BMI and coronal or root caries was observed. For coronal caries, positive SC was found for age (0.56; p < 0.01) and sex (female) (0.14; p < 0.01). For root caries, positive SC was detected for age (0.34; p < 0.01), smoking exposure (0.17; p < 0.01) and gingivitis (0.08; p < 0.01).

Overweight and obese adults should not be regarded at higher risk for dental caries.