Background: Universal health care (UHC) may assist families whose children are most prone to early childhood caries (ECC) in accessing dental treatment and prevention. The purpose of this study was to determine the association between UHC, health expenditure and the global prevalence of ECC. Methods: Health expenditure as percentage of gross domestic product, UHC service coverage index, and the percentage of 3–5-year-old children with ECC were compared among countries with various income levels using one-way analysis of variance (ANOVA). Three linear regression models were developed, and each was adjusted for the country income level with the prevalence of ECC in 3–5-year-old children being the dependent variable. In model 1, UHC service coverage index was the independent variable whereas in model 2, the independent variable was the health expenditure as percentage of GDP. Model 3 included both independent variables together. Regression coefficients (B), 95% confidence intervals (CIs), P values, and partial eta squared (ƞ2) as measure of effect size were calculated. Results: Linear regression including both independent factors revealed that health expenditure as percentage of GDP (P < 0.0001) was significantly associated with the percentage of ECC in 3–5-year-old children while UHC service coverage index was not significantly associated with the prevalence of ECC (P = 0.05). Every 1% increase in GDP allocated to health expenditure was associated with a 3.7% lower percentage of children with ECC (B = − 3.71, 95% CI: − 5.51, − 1.91). UHC service coverage index was not associated with the percentage of children with ECC (B = 0.61, 95% CI: − 0.01, 1.23). The impact of health expenditure on the prevalence of ECC was stronger than that of UHC coverage on the prevalence of ECC (ƞ2 = 0.18 vs. 0.05). Conclusions: Higher expenditure on health care may be associated with lower prevalence of ECC and may be a more viable approach to reducing early childhood oral health disparities than UHC alone. The findings suggest that currently, UHC is weakly associated with lower global prevalence of ECC.
This was an ecological study based on data for UHC service coverage, health expenditure as percentage of gross domestic product (GDP), and the global prevalence of ECC in 3–5-year-old children. Additional file 1: Table S1 shows the values of the variables used for this study. These were: Data on ECC prevalence were extracted from the World Health Organization Country Oral Health Profile database and studies published and indexed in MEDLINE, Scopus, Web of Science and Google Scholar covering the period 2007 to 2017. No language filter was applied. The retrieved data were used to calculate the ECC prevalence for each country by dividing the number of children affected by ECC in each study by the number of children examined and multiplying by 100. In the present study, we used the prevalence of ECC for 3–5-year-old children. Further details were reported in our previous paper [16]. Universal health service coverage index data were obtained from the World Bank Data Bank [24]. The index reflects the extent to which people receive healthcare services they need. Data used to calculate the index were obtained from responses to international surveys such as the Demographic Health Survey and the Multiple Indicator Cluster Survey. It represents coverage for essential health services (based on tracer interventions that include reproductive, maternal, newborn and child health, infectious diseases, noncommunicable diseases and service capacity and access). It is presented on a scale of 0 to 100 with higher values indicating greater coverage. The data for 2017 were used for this study. It indicates health expenditure as percentage of GDP obtained from the World Bank Databank [25]. Estimates of the current health expenditures include healthcare goods and services consumed per year. This indicator does not include capital health expenditures such as buildings, machinery, information technology and stocks of vaccines for emergency or outbreaks. Data for 2017 were used to calculate this indicator. Country income level is associated with ECC [16], universal health coverage [26] and total health expenditure [27]. We adjusted for country income level based on the 2017 Gross National Income (GNI) per capita calculated using the World Bank Atlas method [28]. Countries were grouped as: low-income (LICs-GDP of $995 or less); lower-middle-income (LMICs—GDP of $996–3895); upper-middle-income (UMICs-GDP of $3896–12,055); and high-income (HICs—GDP of $12,056 or more). Total health expenditure, UHC service coverage index, and the percentage of 3- to 5-year-old children with ECC were compared among countries with various income levels using one-way analysis of variance (ANOVA). Scheffe test was then used for post-hoc pairwise comparison. Three linear regression models were developed, and each was adjusted for the confounder (country income level) with the prevalence of ECC in 3–5-year-old children being the dependent variable. To control for the confounder, country income level was forced into each one of the three models so that the estimates produced are adjusted for it in the resulting multivariable models. In model 1, UHC service coverage index was the independent variable whereas in model 2, the independent variable was the health expenditure as percentage of GDP. Model 3 include both independent variables together. Thus, no stepwise selection was used. Based on a conceptual model, all variables were included in the models regardless of their P value. Regression coefficients (B), 95% confidence intervals (CIs), P values, and partial eta squared (ƞ2) as measure of effect size were calculated. Statistical analysis was conducted by SPSS version 22 (IBM Corp., Armonk, N.Y., USA). Significance was set at P < 0.05.