To explore the intra-class transmission pattern of acute hemorrhagic conjunctivitis (AHC) among students, so as to provide a basis for formulating precise prevention and control strategies.

The data of AHC students in 2023 was obtained from the teacher-student health information module of the "Xiamen i-Education" platform. Taking the onset date from January 1st to December 31st, 2023 as the search criteria, the epidemiological data of confirmed AHC cases among students in the whole city in 2023 was collected. And the Knox test method was employed to quantify cluster risk at the class level. Subgroup comparisons were conducted to examine differences in cluster risk between academic stages and gender combinations. Cross-analysis was performed to investigate the interactive effects of two characteristics on cluster risk.

In 2023, 708 cases of AHC students were reported in Xiamen, among which 54 class-clustered outbreaks were identified. These outbreaks accounted for 40.54% of total cases. Among them, the incidence of class-clustered outbreaks with male first-onset cases was higher than that with female first-onset cases (χ²=4.55, P < 0.05). The class cluster risk was at a relatively high level within the incubation period (0-2 d) after AHC onset (RR=4.61-6.43, P < 0.05). Subgroup analysis revealed that female-female case pairs had a higher class cluster risk (RR=4.81-10.29) compared to other gender combinations (P < 0.05). Primary school case pairs showed a higher risk (RR=4.60-6.77) than middle school case pairs (RR=3.85-4.57) (both P < 0.05). Cross-analysis indicated that primary school and female-female combinations had a higher risk (RR=4.70-11.24) than other combinations, while middle school and male-female combinations showed a positive interaction (RR=3.68-6.68)(both P < 0.05).

AHC infection among students is primarily transmitted within classes. Gender and educational stage are key demographic factors influencing class cluster transmission risks. Transmission risks should be assessed by analyzing population characteristics and contact patterns, and targeted interventions should be implemented.

To investigate the interactive effects of prenatal and postnatal factors on overweight and obesity in preschool children, so as to provide evidence for subsequent planning of prevention strategies and intervention measures.

Between October 2020 and June 2021, a convenience cluster sample of 918 preschool children from four kindergartens in Xuzhou urban area underwent questionnaire surveys and physical examinations. The Chi-square test was used to compare intergroup differences in overweight and obesity prevalence. Multivariate Logistic regression analysis was employed to investigate the effects of prenatal and postnatal factors, as well as their interactions, on overweight and obesity in preschool children.

The prevalence of overweight and obesity among preschool children was 30.8%, with boys exhibiting a higher rate (37.0%) than girls (24.8%). Statistically significant differences in overweight and obesity prevalence were observed across age groups, genders, paternal pre-pregnancy body mass index (BMI), paternal educational level, delivery mode, antibiotic use within the six months after birth, and rapid weight gain during infancy (χ²=5.08-17.67, all P < 0.05). After adjusting for confounding factors such as age, gender, the only child, parental educational level and parental average monthly income, interaction analysis revealed that when the father was overweight or obese before conception, children delivered by caesarean section had an increased risk of overweight or obesity (OR=2.05, 95%CI=1.02-3.39), and children with rapid weight gain during infancy also had an increased risk (OR=2.05, 95%CI=1.08-3.88) (both P < 0.05). Gender-stratified analysis revealed that the interaction between paternal pre-pregnancy BMI and mode of delivery on overweight and obesity was more pronounced among girls (OR=4.00, 95%CI=1.51-10.58, P < 0.05). While the interaction between the father's pre-pregnancy BMI and rapid weight gain during infancy was more pronounced in boys (OR=2.85, 95%CI=1.14-7.08, P < 0.05). No significant interactions between prenatal and postnatal factors on overweight and obesity in preschool children were observed (all P>0.05).

Multiple prenatal and postnatal factors influence overweight and obesity in preschool children. Attention should be paid to mode of delivery and infant weight gain, particularly when the father is overweight or obese, to reduce the risk of overweight and obesity in preschool children.

To understand the dose-response relationship between urinary fluoride and dental fluorosis among children from drinking water-borne endemic fluorosis areas in Tianjin, so as to provide a scientific basis for assessing fluoride exposure risk among children from endemic areas and establishing reference values for urinary fluoride.

From January to December 2024, 83 endemic villages were selected in Tianjin. A total of 2 382 children aged 8-12 years from these villages underwent dental fluorosis examination, along with water fluoride and urinary fluoride testing. Additionally, data from areas where the drinking water fluorosis control target was achieved for more than 12 years (10 villages, 50 people per village) were included as controls. A restricted cubic spline model was used to analyze the relationship between urinary fluoride levels and dental fluorosis prevalence, and benchmark dose (BMD) and benchmark dose lower bound (BMDL), as well as reference dose (RfD), were calculated using the benchmark dose method.

The prevalence rates of dental fluorosis among children in drinking water-borne endemic fluorosis areas and areas of normal fluoride content in water in Tianjin were 10.58%, 7.60%, with a geometric mean urinary fluoride level of 0.72 and 0.60 mg/L, respectively. There were statistically significant differences in both dental fluorosis prevalence and geometric mean urinary fluoride levels between the drinking water-borne endemic fluorosis areas group and the areas of normal fluoride content in water (χ²/Z=4.05, -7.31, both P < 0.05). Across different periods of water source improvement, there were statistically significant differences in overall population, male, and female dental fluorosis prevalence rates and geometric mean urinary fluoride levels (χ²/H=44.95, 23.96, 21.05; 168.39, 63.93, 107.50, all P < 0.01). Significant differences were also observed across age groups among children from drinking water-borne endemic fluorosis areas in terms of dental fluorosis prevalence and geometric mean urinary fluoride levels (χ²/H=32.14, 79.73, both P < 0.01). The results of the restricted cubic spline model showed that the risk of dental fluorosis in different sex, age and overall children in the drinking water-borne endemic fluorosis areas increased significantly with rising urinary fluoride concentration(all P_{general trend} < 0.05). The BMD value for the drinking water-borne endemic fluorosis areas was 1.72 mg/L, the BMDL was 1.31 mg/L, and the RfD was 1.31 mg/L.

The prevalence of dental fluorosis among children in the drinking water-borne endemic fluorosis areas in Tianjin has been effectively controlled, but it is still higher than that in the areas of normal fluoride content in water. Moreover, urinary fluoride levels and dental fluorosis prevalence among children from drinking water-borne endemic fluorosis areas show a clear dose-response relationship.

To explore the independent and interactive effects of school green space exposure and outdoor activity duration on screening myopia among primary and secondary school students, so as to provide theoretical support for the prevention and control of screening myopia in children and adolescents.

From September to November 2023, 117 487 primary and secondary school students from 497 schools were selected using a cluster random sampling method, covering 98 counties (cities, districts) in Jiangsu Province. Data on the students' screening myopia status and associated health-influencing factors were collected and analyzed. School green space exposure was quantified using the normalized difference vegetation index (NDVI), which was extracted with ArcGIS Pro software; meanwhile, information on students' outdoor activity duration was gathered through self-reported questionnaires. Multivariate Logistic regression was applied to assess the independent and interactive effects of green space exposure and outdoor activity duration on screening myopia among primary and secondary school students.

Univariate analysis showed that there were statistically significant differences in screening myopia detection rates among primary and secondary school students of different genders, NDVI groups, every outdoor activity duration, monitoring points, school stages, parents' educational level, and whether they lived on campus or had parents with screening myopia (χ²=88.91-1 950.08, all P < 0.05); as the school age and sedentary time increased, the detection rate of screening myopia in primary and secondary school students also increased (χ_trend²=8 410.15, 2 028.91, both P < 0.05). Independent effects showed that compared to the low NDVI group, the medium and high NDVI groups had lower risks of screening myopia (OR=0.93, 0.95, both P < 0.05). Compared to those with outdoor activity duration < 2 h/d, students with outdoor activity duration≥2 h/d had a lower risk of screening myopia (OR=0.96, P < 0.05). When stratified by school level, compared to the low NDVI group, the medium NDVI group had lower risks of screening myopia in primary and junior high schools (primary school: OR=0.91; junior high school: OR=0.88, both P < 0.05). Compared to those with outdoor activity duration < 2 h/d, junior high school students with outdoor activity duration≥2 h/d had a lower risk of screening myopia (OR=0.90, P < 0.05). When stratified by monitoring site, urban primary and secondary school students in the medium and high NDVI groups and those with outdoor activity duration≥2 h/d had lower risks of screening myopia (OR=0.92, 0.92, 0.93, all P < 0.05). Interactive effects showed that when medium or high NDVI was combined with outdoor activity duration≥2 h/d, the risks of screening myopia among primary and secondary school students were lower (medium NDVI×≥2 h/d: OR=0.89; high NDVI×≥2 h/d: OR=0.89, both P < 0.05), and the combined effect was superior to that of a single factor.

Green space exposure and outdoor activity duration have negative correlations with screening myopia among primary and secondary students, and the combined effect is better than that of a single factor.

To investigate the latent classes, transition patterns and influencing factors of bullying victimization among rural junior high school students in Guangxi, so as to provide a theoretical basis for prevention and intervention strategies of school bulling.

In May 2024 (T1), 1 667 students from three rural junior high schools in Guigang and Qinzhou of Guangxi were selected by using convenience cluster sampling to complete the Delaware Bullying Victimization Scale-Student (DBVS-S), Childhood Trauma Questionnaire, School Connectedness Scale and Brief Resilience Scale. In May 2025 (T2), the DBVS-S was readministered. Latent transition analysis was employed to identify the best latent class model of bullying victimization at two time points and to examine the stability and transition characteristics of victimization types. Multinomial Logistic regression was further applied to examine the predictive effects of childhood trauma, psychological resilience, and school connectedness on transitions between bullying victimization categories.

Two distinct patterns of bullying victimization among rural junior high school students were identified at both time points: a low victimization group (91.8% at T1, 93.5% at T2) and a traditional victimization group(high scores in the dimensions of verbal, physical and relational bullying)(8.2% at T1, 6.5% at T2). The low victimization group showed a stability probability of 95.7%, while 59.1% of the traditional victimization group transitioned to the low victimization group. Using the subjects remaining in the original group as a reference, factors associated with increased likelihood of transitioning to or remaining in the traditional victimization group included being male (OR=2.05), emotional abuse (OR=1.21), and physical neglect (OR=1.11)(all P < 0.05). In contrast, psychological resilience and school connectedness were associated with reduced probability of the transition victimization group (OR=0.88, 0.94)(both P < 0.05). Additionally, emotional abuse decreased the probability of transitioning back to low victimization (OR=0.88), whereas psychological resilience increased the probability of students transitioning to the low bulling victim group (OR=1.09) (both P < 0.05).

Group heterageneity is evident in the school bullying victimization among rural junior high school students in Guangxi, and childhood trauma, psychological resilience and school connectedness are important predictors of the transformation of school bullying victim categories.