BackgroundSeveral maternal health determinants during the first period of life of the child, as feeding practice, smoking habit and socio-economic level, are involved in early childhood health problems, as caries development. The potential associations among early childhood caries, feeding practices, maternal and environmental smoking exposure, Socio-Economic Status (SES) and several behavioral determinants were investigated.MethodsItalian toddlers (n = 2395) aged 24–30 months were recruited and information on feeding practices, sweet dietary habit, maternal smoking habit, SES, and fluoride supplementation in the first year of life was obtained throughout a questionnaire administered to mothers. Caries lesions in toddlers were identified in visual/tactile examinations and classified using the International Caries Detection and Assessment System (ICDAS). Associations between toddlers’ caries data and mothers’ questionnaire data were assessed using chi-squared test. Ordinal logistic regression was used to analyze associations among caries severity level (ICDAS score), behavioral factors and SES (using mean housing price per square meter as a proxy).ResultsCaries prevalence and severity levels were significantly lower in toddlers who were exclusively breastfed and those who received mixed feeding with a moderate–high breast milk component, compared with toddlers who received low mixed feeding and those exclusively fed with formula (p < 0.01). No moderate and high caries severity levels were observed in an exclusively breastfed children. High caries severity levels were significantly associated with sweet beverages (p < 0.04) and SES (p < 0.01). Toddlers whose mothers smoked five or more cigarettes/day during pregnancy showed a higher caries severity level (p < 0.01) respect to those whose mothers did not smoke. Environmental exposure to smoke during the first year of life was also significantly associated with caries severity (odds ratio =7.14, 95% confidence interval = 6.07-7.28). No association was observed between caries severity level and fluoride supplementation. More than 50% of toddlers belonging to families with a low SES, showed moderate or high severity caries levels (p < 0.01).ConclusionsHigher caries severity levels were observed in toddlers fed with infant formula and exposed to smoke during pregnancy living in area with a low mean housing price per square meter.