Background Smartphone overuse has been cited as a potentially modifiable risk factor that can result in visual impairment. However, reported associations between smartphone overuse and visual impairment have been inconsistent. Objective The aim of this systematic review was to determine the association between smartphone overuse and visual impairment, including myopia, blurred vision, and poor vision, in children and young adults. Methods We conducted a systematic search in the Cochrane Library, PubMed, EMBASE, Web of Science Core Collection, and ScienceDirect databases since the beginning of the databases up to June 2020. Fourteen eligible studies (10 cross-sectional studies and 4 controlled trials) were identified, which included a total of 27,110 subjects with a mean age ranging from 9.5 to 26.0 years. We used a random-effects model for meta-analysis of the 10 cross-sectional studies (26,962 subjects) and a fixed-effects model for meta-analysis of the 4 controlled trials (148 subjects) to combine odds ratios (ORs) and effect sizes (ES). The I2 statistic was used to assess heterogeneity. Results A pooled OR of 1.05 (95% CI 0.98-1.13, P=.16) was obtained from the cross-sectional studies, suggesting that smartphone overuse is not significantly associated with myopia, poor vision, or blurred vision; however, these visual impairments together were more apparent in children (OR 1.06, 95% CI 0.99-1.14, P=.09) than in young adults (OR 0.91, 95% CI 0.57-1.46,P=.71). For the 4 controlled trials, the smartphone overuse groups showed worse visual function scores compared with the reduced-use groups. The pooled ES was 0.76 (95% CI 0.53-0.99), which was statistically significant (P<.001). Conclusions Longer smartphone use may increase the likelihood of ocular symptoms, including myopia, asthenopia, and ocular surface disease, especially in children. Thus, regulating use time and restricting the prolonged use of smartphones may prevent ocular and visual symptoms. Further research on the patterns of use, with longer follow up on the longitudinal associations, will help to inform detailed guidelines and recommendations for smartphone use in children and young adults.

Objective: To examine the mediating effects of maternal perception of child weight (weight perception) and concern about overweight (weight concern) on the paths between child weight and maternal feeding practices. Setting: Pudong District, Shanghai, China. Participants: A convenience sample of 1164 mothers who were primary caregivers of preschool children. Results: Sixty percent of the mothers perceived their overweight/obese children as normal weight or even underweight. The disagreement between actual child weight and maternal weight perception was statistically significant (Kappa = 0.212, P < 0.001). Structural equation modeling (SEM) indicated that weight perception fully mediated the relationship between child BMI Z-scores and pressure to eat. Weight concern fully mediated the relationships between child BMI Z-scores and the other three feeding practices. The serial mediating effects of weight perception and concern were statistically significant for the paths between child BMI Z-score and monitoring (β = 0.035, P < 0.001), restriction (β = 0.022, P < 0.001), and food as a reward (β = -0.017, P < 0.05). Conclusion: Child weight may influence maternal feeding practices through weight perception and concern. Thus, interventions are needed to increase the accuracy of weight perception, which may influence several maternal feeding practices and thereby contribute to child health.

Background: Parental non-responsive feeding practices and child eating behaviors both play significant roles in childhood obesity. However, their longitudinal relationships are less clear. This systematic review aimed to examine their bidirectional associations. Methods: A systematic search of five databases was conducted from inception to February 2022. Data synthesis was performed using a semi-quantitative and quantitative approach. Results: A total of 14 studies with 15348 respondents were included. A total of 94 longitudinal effects from 14 studies of parental non-responsive feeding practices on child eating behaviors were investigated, and 19 statistically significant effects were discovered. Seventy-seven longitudinal effects from nine studies of child eating behaviors on parental feeding practices were examined, with fifteen being statistically significant. The pooled results of meta-analysis showed five statistically significant associations: parental restrictive feeding positively predicted child enjoyment of food (β = 0.044; 95% CI: 0.004, 0.085); use of food as a reward positively predicted child emotional eating (β = 0.09; 95% CI: 0.04, 0.15); child food responsiveness positively predicted restrictive feeding (β = 0.04; 95% CI: 0.02, 0.06); use food as a reward (β = 0.06; 95% CI: 0.03, 0.10). In addition, the pooled effects showed that child satiety responsiveness negatively predicted restrictive feeding (β = −0.05; 95% CI: −0.08, −0.01). Conclusions: The bidirectional relationships between parental non-responsive feeding practices and child eating behaviors are inconsistent and a few showed statistical significance. Theory-driven longitudinal studies using validated instruments and controlling for potential confounders are needed to unveil their relationships and provide evidence for obesity prevention interventions.