Soft drink consumption and moderating risk factors for dental caries

Background: Because many soft drinks are high in simple carbohydrates they have long been regarded as potentially cariogenic. However, there is still relatively little information available on the nature of the association between soft drink consumption and dental caries. Aims: The current study looked at demographic and socioeconomic differences in soft drink consumption, the association between past and present soft drink consumption and caries experience, as well as factors which might affect the association between current soft drink consumption and caries experience. Methods: A cross-sectional study employing a stratified, clustered sampling design obtained information on 16,526 5–17-year-old children enrolled in school dental services from four Australian states in 2003-2005. Caries experience (dmft and DMFT) was recorded by dentists and dental therapists and parents completed a questionnaire that asked about their child's residential history, sources of water for drinking, toothbrushing frequency, socioeconomic status and soft-drink consumption. The fluoride content of drinking water in Australian localities was used together with children's residential history to calculate lifetime exposure to fluoridated water (LEFW). Analyses used weighted data with corrections for complex survey methodology. Results: Soft drink consumption varied significantly by child age, parental income, state of residence, residential remoteness and by differences in fluoridated water consumption and toothbrushing frequency. Both deciduous and permanent caries experience had a statistically significant association with current soft drink use. Past soft drink consumption at ages 1, 2 or 3 significantly predicted dmft but not DMFT. Finally, the association between soft drink consumption and higher dmft and DMFT was significantly stronger for children with reduced LEFW while parental income was also significantly associated with DMFT. Conclusion: Greater soft drink consumption is related to higher deciduous and permanent caries experience in Australian children but this association is reduced considerably for children who are consuming higher percentages of fluoridated water.