Objective: To explore the role of outdoor activity in the relationship between infancy responsive caregiving trajectories and early childhood development, so as to provide a theoretical basis for the promotion of early child development. Methods: The study participants were drawn from the Shanghai Maternal-Child Pairs Cohort and 4 723 mother-child pairs who completed responsive caregiving questionnaires at 2, 6 and 12 months old were included. Questionnaires were used to assess children s responsive caregiving and average daily hours of outdoor activity at 2 years of age. The Age-Stage Questionnaire, Third Edition (ASQ-3) was used to evaluate children s development problems at 2-5 years old. Group based trajectory model was applied to fit infancy responsive caregiving trajectory. Modified Poisson regression was used to analyze associations between different responsive caregiving trajectory groups and child development, and moderating effects were tested for hours of outdoor activity. Results: Infancy responsive caregiving trajectories were categorized into general group ( n =3 871), declining group( n =160), and fluctuating group( n =646). After adjusting for confounding factors, such as parents educational level, annual household income, maternal progestation body mass index,maternal tobacco exposure during pregnancy,maternal anxiety and depression during pregnancy, maternal age at delivery,maternal gestational age,maternal mode of delivery, children s gender,children s birth weight, and duration of breastfeeding, the results of modified Poission regression analysis showed that compared with the general group, children at the age of 2 in declining and fluctuating group had increased risks of suspected developmental delays in communication, gross motor, fine motor, problem solving, and personal-social scales ( OR =1.41,1.31,1.35,1.23,1.21；1.07,1.08,1.08,1.09,1.06);but children only had increased risk of suspected developmental delays in communication of declining group ( OR =1.08), personal-social scales of fluctuating group ( OR =1.06) at 3-5 years of age ( P <0.05). At lower levels of outdoor activity, children in fluctuating group had reduced scores in communication ( β =-1.41), fine motor ( β =-2.34), problem solving ( β =-1.11) and personal-social scales ( β =-1.99) as compared to general group; and children in declining group had reduced scores in gross motor ( β =-4.78)( P <0.05). While at higher levels of outdoor activity, no differences were found between children in fluctuating, declining groups and those in general group in scores of different scales ( P >0.05). Conclusion Prolonged outdoor activity attenuates the adverse effects of declining and fluctuating trajectories of infancy responsive caregiving on early childhood development.

Objective:To investigate the influence of prenatal stressful life event (SLE) exposure on child emotional and behavioral problem at age 2-6 years and identify the most risk exposure period.Methods:A total of 2 524 mother-child pairs were selected from Shanghai Maternal-Child Pairs Cohort based on pregnant women form 2016 to 2018 in Shanghai. Prenatal SLE exposure was assessed by Life Events Scale for Pregnant Women Questionnaire during the first and third trimester of pregnancy. Child emotional and behavioral problem was evaluated by Strengths and Difficulties Questionnaire at age 2-6 years. Multivariate binary logistic regression model and generalized estimating equation were conducted to quantify the association between prenatal SLE exposure and child emotional and behavioral problem at age 2-6 years, and identify the pregnancy period with strongest adverse effect.Results:The 2 524 mother-child pairs were divided into 4 groups: group with consistent low exposure to SLE (61.8%), group with high exposure to SLE in the first trimester (13.2%), group with high exposure to SLE in the third trimester (13.2%) and group with consistent high exposure to SLE (11.8%). The detection rates of emotional problem, hyperactivity, peer interaction problem and total difficulty score in children aged 3-6 years were highest in the group with consistent high exposure to SLE. Generalized estimating equation analysis showed that after controlling the confounding factors, compared with the consistent low exposure group, the children in the group with high exposure to SLE in the first trimester had significant increased risk for conduct problem at age 2-6 years (a OR=1.41, 95% CI:1.07-1.87). The children in the group with consistent high exposure to SLE were at increased risk for emotional problem, peer interaction problem, and high total difficulty score with the a OR of 1.41 (95% CI: 1.09-1.83), 1.46 (95% CI: 1.15-1.86) and 1.51(95% CI: 1.17-1.93). Conclusion:These findings indicated that prenatal exposure to SLE have adverse effect on child emotional and behavioral problem at age 2-6 years, especially the exposure in the first trimester.

Objective: To understand 24 h physical activity levels of children aged 8-9 years in Pudong New Area and to explore its association with metabolic syndrome, so as to provide scientific basis for children s participation in physical activities and reducing the risk of metabolic syndrome. Methods: A stratified cluster random sampling method was adopted to select 13 schools in Pudong New Area, Shanghai. A total of 2 013 primary school students aged 8-9 years old were included as the research subjects. During September 2021 to December 2022, Actigraph GT3X accelerometer, height measuring gauge, electronic sphygmomanometer and waist circumference tape was used to measure physical activity, height, blood pressure and waist circumference, respectively. A total of 5 mL of venous blood was collected from students, and the levels of triglycerides (TG), highdensity lipoprotein cholesterol (HDL-C) and fasting plasma glucose (FPG) were detected, and online questionnaires were conducted. The ttest and oneway ANOVA were employed to compare the differences in 24 h physical activity levels among children with different characteristics. Multivariate Logistic regression was used to analyze the association between the 24 h physical activity levels and metabolic syndrome as well as its components. Results: Among primary school students, the average daily time of moderate to vigorous physical activity (MVPA) was (34.25±13.49)min, the attainment rate was 1.59%. The average daily sleep (SLP) time was (538.27±28.53) min, attainment rate was 1.89%. The detection rates of metabolic syndrome, abdominal obesity (AO), elevated blood pressure (BP), elevated TG, low HDL-C, and elevated FPG were 2.48%, 34.53%, 10.38%, 10.73%, 1.24% and 0.70%, respectively. Multivariate Logistic regression analysis showed that, for every 10minute increase in sedentary behavior (SB) time, the risks of AO, elevated BP, and elevated TG increased by 2% ( OR=1.02, 95%CI =1.01-1.04), 5% ( OR=1.05, 95%CI =1.01-1.08), and 6% ( OR= 1.06, 95%CI =1.02-1.11), respectively ( P <0.05). For every 10minute increase in MVPA time, the risk of metabolic syndrome decreased by 27% ( OR=0.73, 95%CI=0.57-0.93, P <0.05). For every 10 minute increase in SLP time, the risks of AO, elevated BP, and metabolic syndrome decreased by 16% ( OR=0.84, 95%CI =0.80-0.88), 9% ( OR=0.91, 95%CI =0.82- 0.99 ), and 15% ( OR=0.85, 95%CI =0.77-0.94), respectively （P <0.05). Conclusions The time of MVPA and SLP are seriously insufficient among children aged 8-9 years in Pudong New Area. There is an association between physical activity levels and metabolic syndrome as well as its components. Increasing the time of MVPA and SLP is of great significance for maintaining a relatively low risk of metabolic syndrome in children.