Prolonged breastfeeding, sugar consumption and dental caries at 2 years of age: A birth cohort study

Previous cohort studies have found a positive association between prolonged breastfeeding (≥12 months) on dental caries, but few of them analysed the mediated effect of sugar consumption on this association. This study investigated whether prolonged breastfeeding is a risk factor for caries at 2-year follow-up assessment (21-27 months of age) and whether this effect is mediated by sugar consumption.

A birth cohort study was performed in the Brazilian Amazon (n = 800). Dental caries was assessed using the dmf-t index. Prolonged breastfeeding was the main exposure. Data on baseline covariables and sugar consumption at follow-up visits were analysed. We estimated the OR for total causal effect (TCE) and natural indirect effect (NIE) of prolonged breastfeeding on dental caries using the G-formula.

The prevalence of caries was 22.8% (95% CI: 19.8%-25.8%). Children who were breastfed for 12-23 months (TCE = 1.13, 95% CI: 1.05-1.20) and for ≥24 months (TCE = 1.27, 95% CI: 1.14-1.40) presented a higher risk of caries at age of 2 years than those breastfed <12 months. However, this risk was slightly mediated by a decreased frequency of sugar consumption at age of 2 years only for breastfeeding from 12 to 23 months (NIE; OR = 0.95, 95% CI: 0.91-0.97).

In this study, the effect of prolonged breastfeeding on the increased risk of dental caries was slightly mediated by sugar consumption. Early feeding practices for caries prevention and promoting breastfeeding while avoiding sugar consumption should be targeted in the first 2 years of life.