Maternal smoking during pregnancy was associated with higher odds of childhood caries in the Europe subgroup.
The cross-sectional association remained statistically significant after excluding Julihn et al. 2018.
Maternal smoking during pregnancy was associated with higher odds of childhood caries in the Asia subgroup.
Nocturnal breastfeeding was associated with a significantly increased risk of early childhood caries (RR 2.35, 95% CI 1.42-3.89; substantial heterogeneity; ungraded).
Breastfeeding for <12 vs ≥12 months was associated with significantly fewer caries (RR 0.65, 95% CI 0.50-0.86), indicating breastfeeding beyond 12 months increases ECC risk (substantial heterogeneity; ungraded).
In case-control studies, any breastfeeding versus no breastfeeding was not significantly associated with early childhood caries (OR 1.04, 95% CI 0.78-1.38; ungraded).
Breastfeeding for <24 vs ≥24 months was not significantly associated with early childhood caries in the main analysis (RR 0.59, 95% CI 0.33-1.05; substantial heterogeneity; ungraded).
Breastfeeding for <18 vs ≥18 months was associated with significantly fewer caries (RR 0.41, 95% CI 0.18-0.92; substantial heterogeneity; ungraded).
Breastfeeding for <4 vs ≥4 months was not significantly associated with early childhood caries (RR 0.95, 95% CI 0.80-1.13; ungraded).
In cohort studies, breastfeeding for <6 vs ≥6 months was not significantly associated with early childhood caries (RR 0.97, 95% CI 0.88-1.06; ungraded).