Background
An increase in the number of individuals who are overweight or obese is proving to be one of the most challenging public health problems of the modern era [
1]. Research suggests that there is a positive relationship between childhood obesity and obesity in adulthood [
2,
3]. Dental caries (decay) in children is consistently found to be one of the most common non-communicable diseases worldwide [
4,
5]. The Global Burden of Disease (GBD) 2010 Study found untreated dental caries in permanent teeth to be the most prevalent oral condition globally with around 35% of the population affected [
5]. The consumption of excess free sugar has been implicated in the development of a number of non-communicable and chronic conditions such as obesity, type 2 diabetes and dental caries [
6]. In simple terms, dental caries and body weight are linked via the shared risk factor of diet [
7]. If free sugars are a common risk factor for both dental caries and body weight, what then is the relationship between dental caries and body weight?
An association between these two conditions have been reported in a number of individual studies; however, the results and methodologies are mixed and provide contradictory evidence [
8‐
20]. The relationship between dental caries and body weight in children and adolescents has been looked at in three systematic reviews [
21‐
23]. These reviews suggested that a relationship could exist, but that it is far from simplistic. The Hooley et al. review also found evidence which suggests that a converse, dental caries and low body weight relationship may exist [
21]. In 2015, Public Health England released an evidence summary entitled “The relationship between dental caries and obesity in children” [
24]. This made use of published literature and routine public health monitoring data to review and summarise what is known about the relationship between dental caries and obesity in individuals and populations. The review also found that much of the available evidence was in relation to the obesity and caries relationship in childhood. The results of this evidence summary describe four systematic reviews, the three detailed previously [
21‐
23] and an additional paper by Kantovitz et al [
25]. Again, an equivocal relationship between dental caries and body weight was found. The authors made use of the recently available ROBIS tool which found several of the reviews to be at high risk of bias [
24,
26].
This wealth of varying quality and contradictory evidence suggests the need for an umbrella review to bring together the accessible evidence to permit an understanding of the relationship between dental caries and body weight in children in order to inform policy and potential healthcare intervention. It is expected that this work will be significant in defining the degree of adequacy in the methodological quality and reporting of systematic reviews of observational studies which look at the association between body weight and childhood caries experience.
Objectives
The aim of this umbrella review is to summarise what is already known about the relationship between body weight and childhood dental caries experience in order to make recommendations for policy and to inform healthcare interventions which adopt the Common Risk Factor Approach (CRFA) [
7].
Research question
What is the relationship between dental caries experience and body weight in children?
Inclusion criteria
Types of participants
Participants will be children defined as those under 18 years of age.
Phenomena of interest
The phenomena of interest in terms of the relationship with dental caries experience are body weight. Body weight as measured by weight, BMI, waist circumference or any other recognised methods will be included.
Outcomes
Outcomes for the primary, mixed and secondary dentition will be considered for inclusion. Any measure of dental caries including, but not limited to, DMFT (Decayed, Missing and Filled Teeth), DMFS (Decayed, Missing and Filled Surfaces), and caries incidence will be included.
Context
No limitations will be made in relation to cultural factors such as geographic location, specific racial or gender-based interests.
Types of studies
Studies will be systematic reviews or meta-analyses of observational studies in humans. Systematic reviews or meta-analyses which include cross-sectional, case series, case-control, cohort studies, or aetiology studies using data from an existing database will be included. All systematic reviews which look at the association between dental caries and body weight in children in the same individuals and populations will be considered.
A summary of the main study inclusion and exclusion criteria are provided in Table
1.
Table 1
Study inclusion and exclusion criteria
Types of study | Systematic reviews and meta-analyses | All other types of study |
Period of study | Any systematic review from 1990 to 2017 | Systematic review prior to 1990 |
Types of participants | Children as defined by < 18 years | Studies where children are not the population of interest |
Primary outcomes | Dental caries experience (as measured by any means) | Studies where dental caries is not the outcome of interest, i.e. other dental problems |
Exposure/risk factor phenomena of interest | Body weight as measured by BMI, or any means | Studies which do not look at body weight in relation to dental caries experience |
Language | Full articles in English | Relevant articles in languages other than English |
Review characteristics
Only full articles available in English will be reviewed. A list of possibly relevant titles in other languages will be provided as an appendix. As the availability and methodology of systematic reviews has increased since 1990 [
33], it has been decided a priori to limit the search to systematic reviews from 1990 onwards.
Discussion
This review protocol outlines the process to carry out an umbrella systematic review which will look at existing reviews on childhood dental caries and body weight in order to compare and contrast their findings. The overall aim is to synthesise the available evidence in order to provide an updated summary for policymakers and to better inform healthcare interventions which make use of the CRFA.
Acknowledgements
We thank Andy Jackson, Medical Librarian at the University of Dundee, for his advice in developing the search strategy.
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