Secular trends of dental caries and association with nutritional status: a retrospective analysis of 16,199 Chinese students from three successive national surveys from 2010 to 2019.

Introduction: The prevalence of dental caries (DC) among students in developing countries has increased at an alarming rate, and nutritional status has been shown to be associated with DC in children and adolescents with inconsistent conclusions. We aimed to understand the trends of DC prevalence in students aged 7, 9, 12, and 14 years and to explore the relationship between DC prevalence and nutritional status. Methods: We recruited 16,199 students aged 7, 9, 12, and 14 years in China by multi-stage, stratified, random sampling methods from 2010 to 2019. Permanent caries were measured using the Decay, Loss, and Filling (DMF) index and prevalence rate. Deciduous caries were measured using the decay, loss, and filling (dmf) index and prevalence rate. Nutritional status was assessed using body mass index (BMI) and hemoglobin levels. Logistic regression analysis was used to assess the association between nutritional status and the DC prevalence in children and adolescents, incorporating information concerning family-related factors. Results: The results indicated that DC prevalence increased from 39.75% in 2010 to 53.21% in 2019 in Henan province, with deciduous teeth and permanent teeth being 45.96 and 27.18%, respectively, in 2019. The total caries rate decreased with age (p < 0.05), and the caries rate of girls was higher than that of boys in 2019 (55.75% vs. 50.67%) (p < 0.001). The prevalence of dental caries among primary and secondary school students in areas with medium economic aggregate was the highest, followed by cities with the best economic development level, and cities with low economic levels have a lower prevalence of dental caries. The dental caries prevalence was negatively correlated with body mass index. In the fully adjusted model, underweight children had a higher caries prevalence (OR = 1.10, 95%CI: 0.86-1.41). Children with anemia had a higher prevalence of dental caries (OR = 1.18, 95%CI: 0.98-1.42). Conclusion: The DC prevalence of students in Henan Province was high, with a tendency to increase. Females, young individuals, and those with a higher economic level showed a positive correlation with the prevalence of caries. In the process of economic development, particular attention should be paid to early childhood caries prevention. Nutritional status should be taken seriously among children and adolescents, and the oral health system should be improved to keep pace with economic development.

Analysis of a cohort study on myopia among primary and secondary school students in Henan Province, 2019-2020 / 中国学校卫生

Objective@#To track and investigate the changes in visual acuity of primary and secondary school students in Henan Province during the COVID-19 pandemic home confinement, so as to provide theoretical basis for the prevention and control of myopia.@*Methods@#A cohort study design was employed for this research. In September 2019, visual acuity tests were conducted among 2 222 primary and secondary school students by Multi stage random cluster sampling method from four cities in Henan Province, including Zhengzhou, Xinxiang, Zhoukou, and Pingdingshan. A follow up study was conducted in June 2020, with on site visual acuity tests and questionnaire surveys. Wilcoxon rank sum test, Kruskal Wallis rank sum test, Chi square test, one way analysis of variance, and multiple linear regression model were used to analyze the changes in visual acuity of primary and secondary school students and the influencing factors from 2019 to 2020.@*Results@#Compared with 2019, the overall myopia rate of students increased in 2020, and the difference was statistically significant (55.7%, 64.9%, χ 2=1 035.91, P <0.01), and the difference between mild, moderate and severe myopia rates occurred at 2 years (2019:32.4%, 18.8%, 4.4%, 2020:36.7%, 22.5%, 5.7%, χ 2= 8.43, 9.23, 3.94, P <0.05). The myopia incidence rate of primary and secondary school students in 2020 was 28.3%. As presented in multiple linear regression analysis, middle school, grade 4th-6th and grade 1st-3rd of primary school, low economic level, using television for online classes, the study desk being not bright on sunny days, without looking far away during breaks, the brightness of the study desk and desktop which was average on sunny days, and using roof lamp only when studying at night were associated with myopia progression among students ( B=-0.16, -0.18, -0.20, -0.06, -0.21, -0.13, -0.11, -0.40, P <0.05).@*Conclusions@#During 2019-2020, primary and secondary school students in Henan Province experience a progression towards myopia, which is comprehensively influenced by education stage, economic level, the habit of using eyes, and visual environment. Myopia prevention and control should be actively intervened and strengthened to improve the eye environment for primary and secondary school students, in order to slow down the development of myopia.