Early Childhood Caries in preschool children and its association with other health conditions: Systematic Review and Population-based Data Analysis in the Northern Region of New Zealand

Abstract

Early Childhood Caries (ECC) is a global public health problem. Oral health is integral to the general health of a child, and has the potential to interact with growth and other systemic diseases. Understanding these relationships may bring us an opportunity to identify children at risk of poor health and improve their oral health. Aim This study investigates the association between ECC and (1) Body Mass Index (BMI) distribution and (2) non-dental hospital admissions in preschool children. Methods This thesis has two parts. Part I is a systematic review of published epidemiological studies, which assessed the associations of interest and were published in the English language. Part II involves analyses of oral health data of 523,535 children aged 5 years and under from 2008 to 2015 from oral health datasets (known as Titanium system) of the Northern Region. First, annual ECC prevalence rates were calculated for the Auckland and Northland districts separately and for sub-populations defined by European, Māori, Pacific, Asian and Other ethnic groups. Using the National Health Index (NHI) number, the data on 27,333 children who had oral health assessments at 5 years of age in 2014-2015 were linked to the Before School Check (B4SC) dataset and prior hospital discharge records. Then, the associations of ECC with BMI and prior hospital admissions (categorised as Potentially Avoidable Hospitalisations, Non- Dental (PAHND), respiratory admissions and injury admissions) were examined using logistic regression models. Results Part I: We identified 681 articles, of which 50 studies, which assessed the association between ECC and BMI were included. The findings varied widely, but many studies suggested an association of ECC with unfavourable outcomes (underweight or overweight). We found no study examining the association between ECC and non-dental-related hospital admissions. Part II: In oral health data analysis, a higher prevalence of ECC was identified among children living in the Northland district and Māori and Pacific children. There was a significant association of ECC with higher BMI (≥91st percentile BMI-for-age) and prior hospital admissions for injury at the age of 5 years, but no significant association was observed with PAHND and respiratory admissions. The association with obesity (OR 1.19 (0.99, 1.44)) was not significant but still higher than the association with overweight (OR 1.16 (1.02, 1.32)). The former may just reflect a smaller sample size as the confidence interval is wider. Conclusion Evidence of the association between ECC and BMI is variable. There is a lack of evidence of the association between ECC and non-dental hospital admissions in the existing literature. In this exploratory analysis involving 5-year-old children from the Northern Region of New Zealand, being overweight or obese and having been admitted for an injury were associated with an increased risk of ECC. Future research is required to confirm the findings to better understand the complex associations between ECC and other health conditions, and to develop broader health interventions aiming to improve the well-being of New Zealand children more holistically.