BackgroundDental caries remains the most prevalent chronic condition in children and a major contributor to poor general health. There is ample evidence of a skewed distribution of oral health, with a small proportion of children in the population bearing the majority of the burden of the disease. This minority group is comprised disproportionately of socioeconomically disadvantaged children. An in-depth longitudinal study is needed to better understand the determinants of child oral health, in order to support effective evidence-based policies and interventions in improving child oral health. The aim of the Study of Mothers’ and Infants’ Life Events Affecting Oral Health (SMILE) project is to identify and evaluate the relative importance and timing of critical factors that shape the oral health of young children and then to seek to evaluate those factors in their inter-relationship with socioeconomic influences.Methods/DesignThis investigation will apply an observational prospective study design to a cohort of socioeconomically-diverse South Australian newborns and their mothers, intensively following these dyads as the children grow to toddler age. Mothers of newborn children will be invited to participate in the study in the early post-partum period. At enrolment, data will be collected on parental socioeconomic status, mothers’ general and dental health conditions, details of the pregnancy, infant feeding practice and parental health behaviours and practices. Data on diet and feeding practices, oral health behaviours and practices, and dental visiting patterns will be collected at 3, 6, 12 and 24 months of age. When children turn 24-30 months, the children and their mothers/primary care givers will be invited to an oral examination to record oral health status. Anthropometric assessment will also be conducted.DiscussionThis prospective cohort study will examine a wide range of determinants influencing child oral health and related general conditions such as overweight. It will lead to the evaluation of the inter-relationship among main influences and their relative effect on child oral health. The study findings will provide high level evidence of pathways through which socio-environmental factors impact child oral health. It will also provide an opportunity to examine the relationship between oral health and childhood overweight.

It is important that we monitor socio-economic inequality in health. Inequality in child oral health has been expected to widen because of widening socio-economic inequality. This study aimed to evaluate trends in income-related inequality in caries experience of Australian children. Cross-sectional studies in 1992/93 and 2002/03 collected data on deciduous caries experience of 5- to 10-year-olds and permanent caries experience of 6- to 12-year-olds. Household composition and income was used to calculate quartiles of equivalized income. Slope Index of Inequality (SII), Concentration Index (CI), and regression-based rate ratios were used to quantify income-related inequality and to evaluate trends. Income-related inequality in caries experience was evident regardless of time and dentition. The three indicators of inequality indicate a significant increase in income-related inequality in child deciduous caries experience during the decade. The income inequality in permanent caries experience did not change significantly. Income inequalities increased in deciduous teeth, but not in permanent teeth, among Australian children.

This study aimed to determine whether breastfeeding duration and the timing of solid food were independently associated with being overweight or obese in early childhood. Subjects were 953 children participating in the Study of Mothers and Infants Life Events Affecting Oral Health (SMILE) birth cohort study, based in Adelaide, Australia. Socio-demographic information and data on breastfeeding duration and age of introduction of solid food were collected at birth, 3, 4, 6, 12, and 24 months via mailed or online questionnaires completed by mothers. The weight and height of children were measured at a dental examination when children were aged between 24 and 36 months. Body mass index was calculated, and children were categorised into weight groups according to the World Health Organization growth standards. Multivariable logistic regression analysis was conducted, adjusting for maternal age at birth, education, socio-economic status, pre-pregnancy weight, smoking in pregnancy, method of delivery, and child’s birthweight. Risk of overweight/obesity was independently associated with maternal pre-pregnancy BMI, smoking in pregnancy, and birthweight. Children that were breastfed for 12 months or more had a significantly lower risk of being overweight/obese than those breastfed for less than 17 weeks (AOR 0.49; 95%CI 0.27, 0.90; p for trend =0.009). Age of introduction of solid food, however, was not associated with the risk of being overweight/obese at 24 to 36 months. This study provides further evidence of an inverse relationship between breastfeeding and risk of overweight/obesity, however, no association with the timing of solid food was detected.

Early feeding of free sugars to young children can increase the preference for sweetness and the risk of consuming a cariogenic diet high in free sugars later in life. This study aimed to investigate early life factors influencing early introduction of foods/drinks containing free sugars. Data from an ongoing population-based birth cohort study in Australia were used. Mothers of newborn children completed questionnaires at birth and subsequently at ages 3, 6, 12, and 24 months. The outcome was reported feeding (Yes/No) at age 6–9 months of common foods/drinks sources of free sugars (hereafter referred as foods/drinks with free sugars). Household income quartiles, mother’s sugar-sweetened beverage (SSB) consumption, and other maternal factors were exposure variables. Analysis was conducted progressively from bivariate to multivariable log-binomial regression with robust standard error estimation to calculate prevalence ratios (PR) of being fed foods/drinks with free sugars at an early age (by 6–9 months). Models for both complete cases and with multiple imputations (MI) for missing data were generated. Of 1479 mother/child dyads, 21% of children had been fed foods/drinks with free sugars. There was a strong income gradient and a significant positive association with maternal SSB consumption. In the complete-case model, income Q1 and Q2 had PRs of 1.9 (1.2–3.1) and 1.8 (1.2–2.6) against Q4, respectively. The PR for mothers ingesting SSB everyday was 1.6 (1.2–2.3). The PR for children who had been breastfed to at least three months was 0.6 (0.5–0.8). Similar findings were observed in the MI model. Household income at birth and maternal behaviours were significant determinants of early feeding of foods/drinks with free sugars.

Background Recent reviews have proposed a causal relationship between prolonged breastfeeding and early childhood caries (ECC), but the evidence to date is inconsistent, with few cohort studies and limited investigation of key confounders. Objective This study aimed to investigate the relationship between dietary practices and early childhood caries in a birth cohort of Australian preschoolers. Methods Participants underwent a standardized dental examination at 2–3 y of age to determine the prevalence of ECC (based on the presence of decayed, missing, or filled tooth surfaces). Breastfeeding practices were reported at 3, 6, 12, and 24 mo of age. Intakes of free sugars were assessed at 1 and 2 y of age. Multivariable regression models generated prevalence ratios (PR) for the association between ECC and breastfeeding duration, and between ECC and sleep feeding practices at 1 y, controlling for sociodemographic factors and free sugars intake. Results There was no independent association between breastfeeding beyond 1 y of age and ECC (PR 1.42, 95% CI: 0.85, 2.38), or between breastfeeding to sleep and ECC (PR 1.12, 95% CI: 0.67, 1.88), although the direction of effect was suggestive of an association. The only factors independently associated with ECC were high free sugars intakes (PR 1.97, 95% CI: 1.13, 3.44), and greater socioeconomic disadvantage (PR 2.15, 95% CI: 1.08, 4.28). Most participants who were breastfed at 1 y of age had ceased by 18 mo or 2 y. Conclusions Breastfeeding practices were not associated with ECC. Given the wide-ranging benefits of breastfeeding, and the low prevalence of sustained breastfeeding in this study and Australia in general, recommendations to limit breastfeeding are unwarranted, and breastfeeding should be promoted in line with global and national recommendations. To reduce the prevalence of early childhood caries, improved efforts are needed to limit foods high in free sugars.