Objective: To investigate the prevalence of sleep problems and influencing factors among preschoolers, so as to provide a reference for healthy sleep behaviors among preschoolers. Methods: From December 2017 to June 2018, a questionnaires study was administered to parents of 8 456 preschoolers from kindergartens in Yangzhou, Zhenjiang and Xuzhou by using random cluster sampling method. Demographic characteristics, screen time, sleep patterns and the Children s Sleep Habits Questionnaire (CSHQ) were colleted. Results: The average night sleep duration was (9.91±0.64)h, the rate of sleep deprivation was 51.7%, which increased with age ( χ 2 trend =34.19, P <0.01). The total scores of CSHQ were (49.46±5.02), and the prevalence of sleep problems was 95.0%, with the prevalence of specific sleep problems ranged from 2.3% to 76.4%. Multivariate Logistic regression analysis showed that only child, mothers age, parental education, and household economic status was significantly associated the sleep problems ( P <0.05). Conclusion The prevalence of sleep problems among preschool children is more prominent, varies by only child, parental education and household economic status. Parents and society should raise awareness of sleep problems.

Objective: To explore the correlation between screen time, exposure time to different screens and psychology behaviors of preschool children. Methods: A total of 2 582 children from kindergartens in urban Xuzhou areas were recruited to perform the physical examination, a cluster sampling method being explored. Parent questionnaires were performed to understand the time of screens and children’s psychology behaviors. Multi-linear regression and Logistic regression models were also used to analyze the correlation between them in preschool children. Results: The prevalence of abnormal internalization behavior of preschool children in Xuzhou City was 3.8%, the detection rate of abnormal externalization behavior was 22.4%, and the detection rate of prosocial behavior abnormality was 20.9%. The time spent by the preschool boys on TV time, learning day screen time and one-week video time is significantly higher than the girls (P<0.05). After adjusting for age and gender, the results of multiple linear regression analysis showed that the longer the average screen time, the more serious the problem of internalizing and externalizing problems; and the longer the average screen time of the weekend and the week, the worse the prosocial behavior of children (P<0.05). After correcting multiple covariates, it was found that the average screen time was positively correlated with children’s internal and external behavioral problems (P<0.05). Logistic regression analysis showed that after adjusting for age and gender, the average screen time of study day, weekend and week was a risk factor for preschool children’s internal and external behavior problems, and the average weekly screen time was a protective factor for prosocial behavior (P<0.05). After adjusting for multiple covariates, the learning day and the average weekly screen time were risk factors for children’s internal and external behavior (P<0.05). In addition, the results of association analysis between different types of video time exposure and psychological behavior showed that after adjusting for age and gender, all types of video exposures affected the internal and external behaviors of patients (P<0.05); after correcting multiple covariates The association was still statistically significant (P<0.05). Logistic regression analysis showed that after adjusting for age and gender, the exposure time of each type of video screen was a risk factor for children’s internal and external behavior problems (P<0.05). After correcting multiple covariates, all types of video exposure were internalized behavior problems. The risk factors, and the video time of other electronic products were risk factors for externalization behavior problems (P<0.05). Conclusion Average screen time has a significant positive correlation with psychological behavior, and the exposure time of screens such as TV and mobile phone could increase the incidence of psychological behaviors in preschool children.

Objective: To clarify the distribution of asthma in preschool children aged 3-6 years old and the protective effect of breastfeeding on asthma in three provinces in the middle and lower reaches of the Yangtze river in China. Methods: The parents of 27 200 preschoolers chosen from kindergartens in 11 cities of Hubei, Jiangsu and Anhui Province were investigated with children’s asthma and breastfeeding during October to November in 2017. Results: The asthma detection rate for preschoolers was 4.0%,5.0% for boys and 2.9% for girls. The asthma detection rate for children aged 3,4,5,and 6 years old was 3.2%,3.7%,4.4%,and 4.9%. 3 448 (12.7%) and 7 630 (28.1%) preschoolers were never breastfed or mainly breastfed. The rate of exclusive breastfeeding was 50.0% for 1 to 5 months and only 10.2% over 6 months. Meanwhile,there was a significant protective effect on asthma (OR=0.88,95%CI=0.77-0.89) by exclusive breastfeeding for 1-5 months,which was still statistically significant after adjusting for confounding factors. After adjusting for confounding factors,exclusive breastfeeding over 6 month have significant effected on preschool children aged 4 years old without allergic conjunctivitis history (OR=0.63,95%CI=0.40-0.99). Furthermore,exclusive breastfeeding over 6 month had important effect on preschool children aged 4 years old with eczema history (OR=0.52,95%CI=0.27-0.99). Conclusion Exclusive breastfeeding has protective effect on asthma in preschool children. Exclusive breastfeeding over 6 months even has better protective effect on asthma for the 4-years-old children without the history of allergic conjunctivitis and eczema.

Objective: To examine the relationship of nighttime sleep duration and bedtime with preschool children's obesity, and to explore possible early life risk factors for childhood obesity. Methods: A total of 14 946 valid children from 16 439 pre-school children aged 3-6 years in 91 kindergartens in Ma'anshan city participated in the study. The body mass index cut-offs for overweight and obesity in Chinese children and adolescents aged 2-18 years was used as the criterion for judging overweight and obesity, and pathological and secondary causes of obesity were excluded. The associations of nighttime sleep duration and bedtime with preschool children's obesity was analyzed by using non-conditional multivariate binary logistic regression model. Results: Among the preschool children, 22.4% (n=3 345) had shorter sleep duration. 9.5% (n=1 415) had bedtimes after 22:00 on weekdays and 21.8% (n=3 260) had bedtimes after 22:00 on weekends. The prevalence of overweight and obesity were 16.5% (n=2 466) and 10.5% (n=1 562), respectively. After the adjustent of age, gender, whether or not only child, residence in the last six months, parents' body mass index parents' educational level, diet preference, outdoor activities, TV viewing duration, sleep duration, bedtime on weekdays and weekends, only the shorter sleep duration (OR=1.25, 95%CI: 1.03-1.51) was still positively associated with the prevalence of obesity in preschool children. Conclusion Shorter sleep duration was positively associated with the prevalence of obesity among preschool children.

Objective: To analyze the detection rate of sleep problems such as sleep delay and deficiency in preschool children in the middle and lower reaches of the Yangtze River in China,and to provide the reference for the standard of sleeping mode among preschool students. Methods: From October to November 2017, a questionnaire survey was conducted among 27 200 preschool children in 11 cities in Hubei, Anhui and Jiangsu provinces in the middle and lower reaches of the Yangtze River in China. Epidemiology of sleep delays, deficiencies and sleep patterns in preschool children was described. Results: The detection rate of sleep problems in preschool children in the middle and lower reaches of the Yangtze River was 15.3%. Taking the length of sleep and bedtime as the main analysis points, it was found that the average sleeping time point of each age group was 21:31, and the detection rate of bedtime delay was 86.5%. The average length of sleep was (10.60±1.12) hours. The detection rate of sleep deprivation in preschool children was 15.7%. Sleep delay was positively correlated with girls, age increase and parents’ higher educational level (P<0.05), and negatively correlated with living in the city, non-only child and bedroom without TV (P<0.01) .The detection rate of sleep deprivation was positively correlated with children of high age group (4yearold group：OR=1.32，95%CI=1.19-1.46；5-year-old group：OR=2.10，95%CI=1.91-2.32；6-year-old group：OR=2.47，95%CI=2.20-2.77)(P<0.01), and negatively correlated with no TV in bedroom (OR=0.91，95%CI=0.84-0.98) and no light in sleep (OR=0.87，95%CI=0.78-0.97)(P<0.05). Conclusion Preschool children sleep delay and sleep deprivation and other sleep problems are more prominent, affected by family environment and other factors.

Early life is a critical window period that determines the growth and development of children, but this delicate and complex period is highly susceptible to the disturbance of various exogenous chemicals, which in consequence may lead to short-term or long-term adverse health effects in human beings. The massive use of antibiotics has contributed to widespread exposure in early life, along with the potentially adverse effects on child health, and has caused great concern in public health. This review summarized recent epidemiological studies on the population with early-life antibiotic exposure and associated health outcomes such as growth and development, allergies, and psycho-behavioral problems in children, as well as potential biological mechanisms underlying these associations. Current findings suggested that antibiotic exposure early in life, including pregnancy and infancy, is strongly associated with childhood allergic diseases (e.g., atopic dermatitis and asthma), growth and development (e.g., obesity and birth length), and childhood psycho-behavioral problems (e.g., autism and anxiety). It also suggested that antibiotic exposure may affect individual health through gut microbiota, thyroid function, inflammation factors, mitochondrial function, and epigenetic mechanisms. In the future, more large prospective birth cohorts should be established to determine the levels of internal exposure to different types of antibiotics at multiple time points in early life and to explore their associations with child health outcomes, as well as to further validate relevant mechanisms, aiming to provide high-quality scientific evidence for research on child health associated with environmental exposure in early life.

Objective: To evaluate the positive correlation between excessive screen-watching time, combined effect of screen-watching and outdoor time and the emotional problems in preschool children. Methods: A total of 27 200 preschool children aged 3-6 years in 109 kindergartens in 11 cities in Jiangsu, Hubei, Anhui participated in the study. Information on both screen-watching and outdoor time and social-demographic characteristics was collected through the Questionnaire on the healthy Development of Preschool Children. Emotional problems of these children were accessed by using the Strengths and Difficulties Questionnaire (SDQ). Correlation intensity between excessive screen time and emotional problems (suspicious or abnormal) in preschool children, and the combined effects of screen-watching and outdoor time were analyzed by binary logistic regression model. Results: The overall detected rate of emotional symptoms in preschool children was 17.9% (4 868/27 200). Rates showed in preschool children would include: with screen-watching time>1 h/d as 62.4% (16 983/27 200) and with outdoor time<2 h/d as 65.7% (17 873/27 200). After adjusting for confounding factors as gender, age, place of residence, family economic status, BMI, parents’ age and education level, data showed that the screen-watching time was positive correlated with emotional symptoms (OR=1.15, 95%CI: 1.08-1.24) while the outdoor time was positive correlated with emotional symptoms (OR=1.08, 95%CI: 1.01-1.16). Strong correlation between the combination of screen-watching and outdoor time and the existing emotional problems among preschool children was seen. Conclusions Excessive screen-watching time was prevalent among preschool children. Screen-watching time was positively associated with the existing emotional problems while the combined effect of screen-watching time and outdoor time was stronger.