Abstract: Objective To analyze the comorbidity of dental caries and overweight/obesity and its influencing factors among primary and secondary school students in key monitoring counties under the Henan Rural Compulsory Education Student Nutrition Improvement Plan in 2023, so as to provide a reference for promoting the healthy growth of students. Methods Using a stratified random cluster sampling method, primary and secondary school students in the third grade and above were selected as research subjects from four key monitoring counties implementing the "Rural Compulsory Education Student Nutrition Improvement Plan" in Henan Province in 2023. Examinations of their oral health status, height, and weight were conducted, along with a questionnaire survey. The χ² test was used for inter-group comparisons and univariate analysis, and logistic regression was employed for a multivariate analysis of the correlation between dental caries and the comorbidity of overweight/obesity. Results In 2023, a total of 4 291 primary and secondary school students of grade three and above were sampled from key monitoring counties under the Nutrition Improvement Plan in Henan Province, including 2 176 males and 2 115 females, with an average age of (11.96±2.04) years. The prevalence of dental caries was 42.30% (1 815 cases), the detection rate of overweight and obesity was 31.23% (1 340 cases), and the detection rate of the comorbidity of dental caries with overweight and obesity was 11.63% (499 cases). The detection rate of this comorbidity was higher in county towns (13.65%) than in rural areas (10.99%), higher in primary schools (14.91%) than in junior high schools (7.72%), and higher in non-boarding students (14.07%) than in boarding students (8.82%). The rate also increased with the educational level of both the father and mother (all P<0.05). Multivariate logistic regression results indicated that academic stage (junior high school OR=0.498, 95% CI: 0.406-0.609), picky eating behavior (non-picky eating OR=0.772, 95% CI: 0.636-0.935), maternal educational level (junior high school OR=1.649, 95% CI: 1.290-2.131; college and above OR=1.911, 95% CI: 1.288-2.807), and high-frequency consumption of fried foods (≥5 times/week OR=1.616, 95% CI: 1.023-2.462) were influencing factors for the comorbidity of dental caries and overweight/obesity (all P<0.05). Conclusion In 2023, the prevalence of dental caries, overweight/obesity, and their comorbidity were high among primary and secondary school students in the key monitoring counties of the Henan Rural Compulsory Education Student Nutrition Improvement Plan. The family dietary environment and children's eating habits are closely related to the detection of this comorbidity. It is recommended that health education be further strengthened to guide students in developing good living habits and to support the healthy growth of children.

Key words: Primary and secondary school students, Dental caries, Overweight and obesity, Comorbidity, Influencing factors