Objective: This study aimed to systematically review epidemiological evidence on associations between screen time exposure and myopia in children and adolescents, and to quantitatively evaluate summary effect estimates from existing literature. Method: There were three online databases including PubMed, Embase, and Web of Science, for epidemiological studies on screen time exposure and myopia published before June 1, 2023. The risk of bias was assessed by the Newcastle Ottawa Scale (NOS) checklist. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the correlation between screen time exposure and myopia using random or fixed-effect models by exposure type (categorical/continuous). We also performed subgroup analysis by screen device type, study quality, geographic region, and research period. Results: We searched 7,571 records from three databases and identified 19 eligible studies, including 14 high-quality studies and 5 moderate-quality studies. Meta-analyses suggested that there was a statistically significant correlation between screen time (high vs. low) and myopia. The pooled ORs with 95%CIs were respectively 2.24 (1.47–3.42) for cross-sectional studies, and 2.39 (2.07–2.76) for cohort studies. We also found a significant association between continuous exposure to screen time (per 1 h/d increase) and myopia in cohort studies. The pooled ORs with 95%CIs were 1.07 (1.01–1.13). In subgroup analysis stratified by screen device type in cross-sectional studies, screen time exposures from computers (categorical: OR = 8.19, 95%CI: 4.78–14.04; continuous: OR = 1.22, 95%CI: 1.10–1.35) and televisions (categorical: OR = 1.46, 95%CI: 1.02–2.10) were associated with myopia, while smartphones were not. Although publication bias was detected, the pooled results did not show significant changes after adjustment using the trim and fill method. Conclusion: Our findings support that screen time exposure was significantly associated with myopia in children and adolescents. Notably, screen time exposure from computers may have the most significant impact on myopia.

Myopia has become a significant global public health concern, and is highly prevalent worldwide especially in Asian countries. It is associated with genetic factors as well as socioeconomic status; however, the underlying cause for school myopia has not been established. This study evaluates the impact of living environment on school myopia in Chinese school-aged children. A large cross-sectional sample of area- and ethnicity-matched school children; a total of 43, 771 children from 12 cities participated in this study. The presence of myopia was self-reported and potential risk factors were determined by questionnaires. The self-reported prevalence of myopia in Chinese children was 31.8 % (n = 13, 928). In multiple logistic regression analysis, higer risk of myopia among school-aged children was significantly positively associated with both parental myopia (OR = 3.57; 95 % CI: 3.26–3.90), living in 1–3 floor (OR = 1.28; 95 % CI: 2.57–3.15), 4–6 floor (OR = 1.84; 95 % CI: 1.73–1.95) and 7 floor or more (OR = 2.02; 95 % CI: 1.88–2.16). Particularly, housing type was independently associated with myopia after stratified by parental myopia. An increasing prevalence of myopia was found with increasing floor of housing type in each outdoor time group. Housing type was independently associated with myopia, after stratified by parental myopia. Flat room, lower living floor and more outdoor time may be protective factors for myopia among school-aged children in mainland China.

Previous research has found a relationship between child abuse and non-suicidal self-injury (NSSI). However, few studies have examined the role of social support underlying this association. Moreover, the influence of the only child status on the mediating effect of social support has not been studied yet. The aim of this study was to investigate the mediating role of social support on the association between specific forms of child abuse and NSSI as well as the role of the only child status on the mediated pathways, among undergraduates. A total of 4799 participants were selected from two medical colleges in the Anhui province using stratified cluster sampling. Pearson's correlation analysis was used in analyzing the relationship. Bootstrapping procedures were applied to examine the mediating effects. After adjusting for confounders, the results showed that the mediating effect of social support on the association between childhood abuse and NSSI was not significant in the total sample. However, among only children, the mediating effects of social support between overall childhood abuse, physical abuse, emotional abuse, and NSSI were 9.65%, 14.82%, and 8.12%, respectively. Moreover, the mediating effect of social support from family and relatives was relatively higher than that from other sources. Social support had a mediating effect on the relationship between childhood abuse and NSSI among only-children. The enhancing of social support may contribute to the prevention and control of NSSI for those who were only-children in undergraduates, especially those who have experienced childhood abuse.

Background: Non-suicidal self-injury behavior (NSSI) is a common mental health threat among adolescents. Poor parent-child relationship (PCR) and problematic mobile phone use (PMPU) are risk factors for NSSI. We aimed to explore the impact of PCR quality, PMPU, and their interaction effects on NSSI among adolescents in China, as well as the sex difference. Method: A survey was conducted among school students in 4 provinces in China between 2017 and 2018. The study included 14,500 valid participants. The students’ general demographic characteristics was collected, and further data on PCR quality, PMPU, and NSSI were obtained through self-rated questionnaire. Chi-square test, binomial logistic regression models, and the Andersson Excel were used for data analysis. Results: The 12-month prevalence of NSSI was 27.3%. Lower PCR quality and PMPU were significantly associated with NSSI, respectively. The low PCR + yes PMPU group had the greatest association with NSSI, followed by the high PCR + yes PMPU group, low PCR + no PMPU group. Moreover, in low father-child relationship + yes PMPU group, females had a higher risk of NSSI than males; in high mother-child relationship + yes PMPU group, females had a higher risk of NSSI than males. Additive interaction analysis indicated that mother-child relationship quality and PMPU were associated with increased risks of NSSI, in the subgroup of males. Conclusions: The findings underline the importance of simultaneously studying the quality of PCR and PMPU for a comprehensive understanding of NSSI behavior, and especially highlights the significance of maternal relationship quality.