Family income modifies the association between frequent sugar intake and dental caries.

The aim of the present cross-sectional study was to investigate whether family income modifies associations between dental caries and sex, age, mother's education, type of preschool, sugar intake and tooth brushing. A randomly selected sample of 308 Brazilian preschool children aged one to three years underwent a clinical oral examination for the assessment of moderate/extensive dental caries using codes 3 to 6 of the International Caries Detection and Assessment System. Mothers were asked to fill out a form addressing the child's demographic and socioeconomic characteristics as well as the frequency of sugar intake. Statistical analysis involved descriptive statistics, the chi-squared test and Poisson regression models. The prevalence of moderate/extensive dental caries was 42.5%. The adjusted model revealed that within low-income families (<2 times the monthly minimum wage), the prevalence of dental caries was higher among children with a high frequency of sugar intake (≥ twice per day) than in those with a low frequency of sugar intake (< twice a day) (RR=1.79; CI: 1.38-2.33). However, in families with higher income (≥2 times the monthly wage), no significant association between sugar intake and dental caries was found. In conclusion, monthly family income can modify the association between the high frequency of sugar intake and dental caries.