Effect of body weight and behavioural factors on caries severity in Mexican rural and urban adolescents

Objectives: To investigate if, in Mexican adolescents, body weight and caries severity are associated, and if this association differs between rural and urban populations. Methods: Adolescents from the rural area of Tepancan and the city of Veracruz were enrolled. Caries was recorded using the International Caries Detection and Assessment System and the body mass index (BMI) was calculated. Oral habits (toothbrushing, flossing, dental check-ups) and dietary patterns (sweets intake) were assessed. A dummy variable between BMI and living area (BMI/Area) was generated. Data were analysed using STATA and a multinomial logistic regression model was run, using caries severity as the dependent variable. Results: Four-hundred and sixty-four subjects, 12-15 years of age, participated (rural = 240; urban = 224). The BMI and area of residence were significantly associated (χ2= 12.59, P < 0.01). Area was also associated with caries severity (χ2= 24.23, P < 0.01), with the highest number of caries in dentine recorded in participants from the rural area. The dummy variable BMI/Area was related to caries severity (χ2= 27.47, P < 0.01): overweight adolescents with caries in dentine were most frequently found in the rural area. A higher prevalence of caries in enamel and a lower prevalence of caries in dentine (P < 0.01) were recorded in adolescents from the urban area, where better oral habits, but higher sweets intake (P = 0.04), were encountered. According to the multinomial logistic regression model, BMI/Area was significantly associated with caries severity (P < 0.01). Conclusions: Overweight was not associated with caries severity in the overall population, but it became a statistically significant risk indicator in adolescents living in the rural area.