Evidence suggests that excessive screen time in early childhood is related to children’s physical and mental health. This study aimed to review the relationships between screen media use and several health indicators in infants, toddlers, and preschoolers. A systematic search was conducted by two independent reviewers on PubMed, Web of Science, Embase, and Cochrane Library to identify the eligible studies, with an end date of 13 August 2019. Included studies (published in English) were peer-reviewed and met the determinate population (children aged 0–7 years with screen media exposure and related health outcomes). The AHRQ, NOS, and the Cochrane Handbook were used to evaluate the cross-sectional study, cohort study, and RCT, respectively. A meta-analysis and narrative syntheses were employed separately. Eighty studies (23 studies for meta-analysis) met the inclusion criteria for the systematic review. Strong evidence of the meta-analysis suggested that excessive screen time was associated with overweight/obesity and shorter sleep duration among toddlers and preschoolers. Excessive screen use was associated with various health indicators in physical, behavioral, and psychosocial aspects. Better-quality research on newer media devices, on various kinds of contents in young children, and on dose–response relationships between excessive screen use and health indicators are needed to update recommendations of screen use.

Substantial evidence indicates that the relationship between blood pressure (BP) measures and cognitive functioning is inconsistent, complex, and age-related. Pulse pressure (PP), which can not only reflect arterial stiffness and but also represent the chronic effects of hypertension other than BP itself, has been considered as a better predictor of cognitive impairment. However, evidence on the association of cognitive function with PP has not been investigated extensively. We examined this relationship in a longitudinal study based on the latent growth model (LGM). This study was based on a nationally representative sample of Chinese middle-aged and older participants from the China Health and Retirement Longitudinal Study (CHARLS), a prospective observational study conducted from 2011 to 2016. Cognitive performance was assessed on the basis of three measures of cognition. The PP was calculated as the difference of the average values of three systolic and diastolic BP readings. A series of potential confounders were collected in this research. The LGM was used to examine the effects of PP on cognitive performance at three time points. To test the independent effects of PP on the initial level and the subsequent development of cognition, unconditional and conditional models were compared sequentially. After excluding respondents with missing key variables, we ultimately included 9750 participants in the analysis. Cognitive performance scores and PP showed significant differences across time. After adjustment for the confounders, the standardized coefficients of PP in the LGM indicated negative effects on cognitive performance in elderly Chinese participants at wave 2 and wave 3 (P < 0.01). The initial level of PP in the unconditional model was negatively associated with the initial level (β = − 0.25) and the slope (β = − 0.16) of cognition, whereas these effects were attenuated and the association between intercept of PP and slope of cognition became nonsignificant after controlling for the confounders. The implications of these results demonstrate that a higher PP lowers the cognitive performance of middle-aged and elderly persons independent of a comprehensive set of covariates, but it is not a contributor to the rate of change in cognition.

Objectives A prospective study was performed to examine the relationship of childhood socioeconomic status (SES) with cognition and the rate of change in a nationally representative sample of community-dwelling middle-aged and older Chinese population. Methods This study mainly focused on 3 composite measures of cognitive function, including Telephone Interview of Cognitive Status, word recall, and drawing a figure successfully. Childhood SES was evaluated by parental occupation and education, childhood residence, and self-evaluated financial status. We designed an analysis strategy adding predictors incrementally in different models to examine the changes of effects of childhood SES on cognition by latent growth curve models. Results Finally, a total of 10 533 respondents were prospectively studied, including 5980 respondents aged 45-59 and 4553 aged 60-90. Cognition in younger cohort showed a curvilinear change, while cognition in older cohort showed a linear decline. After controlling for covariates, middle-aged respondents with higher self-evaluated financial status (β: -0.22, P < .001), better health status (β: -0.13, P < .001), higher parental education (β: 0.17 and 0.10, P < .001), who had lived in city/town before 16 years (β: 0.69, P < .001), and whose fathers engaged in nonfarming work (β: 0.43, P < .001) were associated with the better baseline cognition. Similar results were found in older cohort. Additionally, early-life SES was not associated with cognitive decline in both cohorts. Conclusions This study indicates that childhood SES is associated with mid-life and late-life baseline cognition, but it is not contributed to cognition decline. Interventions in early-life focused on improving childhood SES might have positive impacts on baseline cognition in later-life.

Few prospective birth cohort studies are available on the effects of prenatal and early-life exposures on food allergy and eczema among Chinese children. The aim of this study was to evaluate the influence of prenatal and early-life exposures on food allergy and eczema during the first year of life in a prospective birth cohort study. This study was based on a prospective, observational birth cohort of 976 mother-child pairs in three Streets in Changsha, China from January to December 2015. Data on prenatal, early-life exposures and allergic outcomes were obtained from questionnaires collected at birth, and 1, 3, 6, 8, and 12 months of age. Multivariate logistic regression models were performed to estimate the effects of prenatal and early-life exposures on food allergy and eczema. Common risk factors for food allergy and eczema in infancy were parental history of allergy, while moderate eggs consumption (3–4 times/week) during pregnancy was protective for both of them compared with low consumption (≤ 2 times/week). Factors only associated with food allergy were maternal aquatic products consumption during pregnancy, number of older siblings and age of solid food introduction, whereas factors only associated with eczema were maternal milk or milk products consumption during pregnancy, maternal antibiotic exposure during pregnancy, season of birth and antibiotic exposure through medication during the first year of life. Our study suggests that factors associated with food allergy and eczema are multifaceted, which involving hereditary, environmental and nutritional exposures. Furthermore, differential factors influence the development of food allergy and eczema in infants.

This study aimed to examine the associations between the duration of folic acid (FA) supplementation, gestational diabetes mellitus (GDM), and adverse birth outcomes. A total of 950 mother-offspring pairs participated in the cohort study during 2015 in Changsha, China. The data were collected through home visits and perfected by maternal and child healthcare handbooks. Generalized linear models and stratified analyses were used for statistical analyses. The incidence of GDM in our cohort was 10.2%. FA supplementation for ≥3 months before pregnancy was associated with an increased risk of GDM (adjusted relative risk (aRR): 1.72; 95% CI: 1.17–2.53) and decreased risk of small-for-gestational-age (SGA) birth (aRR: 0.40; 95% CI: 0.18–0.88). In the group of FA supplementation for ≥3 months during pregnancy, GDM was associated with an increased risk of cesarean delivery (aRR: 1.36; 95% CI: 1.06–1.75) and macrosomia (aRR: 2.11; 95% CI: 1.06, 4.20), but the aRRs were lower than the RR_MH 1.53 (95% CI: 1.01–2.34) and 2.43 (95% CI: 1.27–4.66). Our study suggested that the longer duration of FA supplementation before pregnancy might increase the risk of GDM, but decrease the risk of SGA birth. Longer duration of FA supplementation during pregnancy had beneficial effects on birth outcomes in women with GDM. Further studies should consider a larger sample size to confirm these findings.