The relationship between nutrition, diet, and early childhood caries: A cross-sectional study using 2009 to 2014 NHANES data

Early childhood caries (ECC) is a major public health issue influenced by nutritional, behavioral, and sociodemographic factors. However, the independent effects and dose-response patterns of key risk factors remain unclear. This study aimed to analyze the associations between nutritional and dietary factors and ECC using nationally representative data, and to explore the nonlinear relationship between calcium intake and ECC. Data from 2564 children aged 2 to 6 years were obtained from the National Health and Nutrition Examination Survey 2009 to 2014. Weighted chi-square tests compared baseline characteristics between ECC and non-ECC groups. Multivariate logistic regression assessed the effects of age, calcium, fat, vitamin D, and other factors on ECC. Restricted cubic spline regression explored the nonlinear association between calcium intake and ECC. Forest plots and correlation analyses evaluated the strength of these associations. Significant differences were observed between groups in ethnicity, breastfeeding history, age, calcium and fat intake. Caries prevalence was higher in Mexican Americans (29.1%), breastfed children (61.4%), and 6-year-olds (29.4%). Children with ECC had lower calcium intake (838 vs 893 mg) and higher fat intake. Regression analysis showed that ECC risk increased with age (odds ratio = 6.319, P < .001). Restricted cubic spline analysis revealed a significant nonlinear relationship between calcium intake and ECC ( P = .011), with an inflection point at 1000 mg/day. Below this threshold, increased calcium intake was associated with reduced ECC risk; above it, the effect plateaued. Vitamin D was not significantly associated with ECC. This study identifies 1000 mg/day as a potential threshold for calcium intake in reducing ECC risk. Increasing age and insufficient calcium intake are independent risk factors for ECC. These findings support the development of targeted interventions focusing on dietary optimization, oral microbiota regulation, and feeding behavior adjustment in high-risk pediatric populations.