Summary Children are especially vulnerable to lead toxicity, and exposure to lead has been linked to poor school performance and delinquency in children and adolescents. Even low-level lead exposure (blood lead level [BLL] lower than 10 µg/dL) can cause intelligence deficit. In China, BLLs in children decreased slightly after the phase-out of lead in gasoline, but few studies have examined the socio-demographic factors associated with BLL above 10 µg/dL. In thus study, we sought to examine the hypothesis that socio-demographic factors predict BLLs. We measured BLLs of 1,344 preschool children (3–5 years old) from the China Jintan Child Cohort Study. Children’s socio-demographics and health statuses, as well as parental socio-demographics, were collected through questionnaire. Multiple regression models were used to explore the association between socio-demographic factors and log-transformed BLLs as well as the relationship between socio-demographic factors and the risk of BLL above 10 µg/dL. We found the median BLL to be 6.2 µg/dL (range: 1.8–32.0 µg/dL), and 8% of children had BLLs above 10 µg/dL. Boys had a higher median BLL (6.4 µg/dL) than girls and were more likely to have BLL above 10 µg/dL (OR=1.77, 95% CI 1.14 –2.74). BLLs increased as children aged, with a median BLL of 6.6 µg/dL among 5-year old children. Children with sibling(s) had higher average BLL and prevalence of BLL above 10 µg/dL than those without sibling(s). Living in a crowded neighborhood was also associated with increased BLLs. Mother’s lower education, father’s occupation (as professional worker), and parental smoking at home were associated with increased BLLs. This study shows that children in this area still have relatively high BLLs after the phase-out of leaded gasoline. Both children’s and parental factors and community condition are associated with increased BLLs. Future efforts are needed to identify other exposure sources and develop targeted prevention strategies.

Objective To examine sleep problems and fatigue and their associations with cognitive performance in Chinese kindergarten children. Study design A cross-sectional analysis of baseline data from Jintan Child Cohort Study was conducted, which includes a cohort of 1,656 kindergarten children in Jintan City, Jiangsu Province, China. The sample used in the current study consisted of 1,385 children (44.8% girls, mean age 5.72 (SD=0.42) years) for whom data on sleep problems or cognitive performance were available. Child Behavior Checklist was used to measure child sleep problems and fatigue, and Wechsler Preschool and Primary Scale of Intelligence – Revised was used to assess child intelligence quotient (IQ). Results Sleep problems were prevalent, ranging from 8.9% for difficulty maintaining sleep (DMS) to 70.5% for unwilling to sleep alone. Other reported sleep problems were difficulty initiating sleep (39.4%), nightmares (31.6%), sleep talking (28%), sleeping less (24.7%), and sleep resistance (23.4%). Fatigue was also prevalent, with 29.6% of children reported to be overtired and 12.6% lack of energy. Children with DMS, sleep talking, sleep resistance, or nightmares scored 2-3 points lower in full IQ than children without sleep problems. Children reported to have fatigue scored 3-6 points lower in full IQ than those children without fatigue. Conclusions Sleep problems and fatigue are prevalent in Chinese kindergarten children. Furthermore, sleep problems and fatigue are associated with poor cognitive performance.

Background Although the prevalence of malnutrition has decreased, micronutrient deficiency still exists among children. While iron level has been studied, limited information on serum levels of zinc in Chinese children is available. This study aims to describe the status of micronutrients and its association with sociodemographic factors, and to assess associated risk factors. Methods A cross-sectional study was performed on 1375 Chinese preschool children. Venous blood samples were collected and analyzed for zinc and iron by atomic absorption spectrophotometry. Sociodemographic information was obtained from self-administered questionnaires given to the parents. Results The high prevalence of low serum zinc (38.2%) and iron (24.3%) was found. Children from rural preschools had the lowest zinc levels, whereas those from urban preschools had the lowest iron levels. Children living in small houses had the highest prevalence of low serum zinc (47.1%), and children from small families (≤3 persons) had a higher prevalence of low serum zinc than those from large families (41.8% vs. 34.1%). Conclusions Our findings in the recent socioeconomic development of China suggest the need for continuous monitoring of nutritional factors and highlight the importance of public health implication in preschool children even in developed regions.

Background Despite the body of literature that links anemia with poorer cognition in children and the evidence that the severity of the effects of anemia on children’s cognition vary in different populations, few studies have investigated the effects of anemia on the cognitive development of Chinese children. Study Design This longitudinal cohort includes 171 children from a developing region of China. Hemoglobin and iron levels were taken when the children were 4 years old. At age 6, the children’s cognition was tested with Chinese WPPSI. Psychosocial information was also used in analyses. Results Results showed that the children who had low Hb levels had significantly lower scores in PIQ, but not VIQ. Although blood Fe levels were not shown to moderate the link between hemoglobin levels and IQ, we found children who performed the best on IQ tests exhibited low iron levels concurrent with high hemoglobin levels, whereas the group who performed the worst exhibited high iron but low hemoglobin levels. We also found that psychosocial adversity did not differ significantly between children who had normal or low hemoglobin levels, although the effect of hemoglobin on PIQ became only suggestive after controlling for psychosocial adversity, therefore the relationship is not causal but only a suggestive association. Conclusion Our findings are in agreement with literature on the negative effects of anemia on children’s cognition and point to the possibility that the portions of the brain associated with PIQ components are particularly affected by low Hb during crucial periods of development.

Background While the impact of active maternal smoking during pregnancy on child health has been well investigated, the association between maternal passive smoking, or environmental tobacco smoke (ETS), or second-hand smoke, and behavioral development of offspring is less clear. This study examines the association between maternal ETS exposure during pregnancy and child behavior problems. Methods Cross-sectional data of 646 mother–child pairs from the Jintan China Cohort Study were used in the analyses. Mother’s exposure to tobacco smoking at home, the workplace, and other places during pregnancy (for the determination of maternal ETS exposure) and children’s behaviors (via Child Behavior Checklist) were assessed when the children were 5–6 years old. Logistic regression models were constructed to examine associations between maternal exposure to ETS during pregnancy and internalizing and externalizing behavior problems, adjusting for potential cofounders including child sex and parental characteristics. Results 37% of mothers reported ETS during pregnancy. Children of mothers exposed to ETS during pregnancy had higher scores for externalizing and total behavior problems, with 25% of children whose mothers were exposed to ETS compared to 16% of children of unexposed mothers. After adjusting for potential confounders, ETS exposure was associated with a higher risk of externalizing behavior problems in offspring of exposed mothers (OR = 2.08, 95% confidence interval [CI] 1.27–3.43). Analysis after multiple imputations and sensitivity analysis further verified the association, but no dose–response relationship was found. ETS exposure, however, was not associated with internalizing or total behavior problems. Conclusion This study suggests that maternal ETS exposure during pregnancy may impact child behavioral development, particularly externalizing behaviors.

The China Jintan Child Cohort study began in 2004 with 1656 pre-school participants and a research focus on studying the impact of environmental exposures, such as lead, on children's neurobehavioural outcomes. This population cohort now includes around 1000 of the original participants, who have been assessed three times over a period of 10 years. Since the original IJE cohort profile publication in 2010, participants have experienced a critical developmental transition from pre-school to school age and then adolescence. The study has also witnessed an increase in breadth and depth of data collection from the original aim of risk assessment. This cohort has added new directions to investigate the mechanisms and protective factors for the relationship between early health factors and child physical and mental health outcomes, with an emphasis on neurobehavioural consequences. The study now encompasses 11 domains, composed of repeated measures of the original variables and new domains of biomarkers, sleep, psychophysiology, neurocognition, personality, peer relationship, mindfulness and family dynamics. Depth of evaluation has increased from parent/teacher report to self/peer report and intergenerational family report. Consequently, the cohort has additional directions to include: (i) classmates of the original cohort participants for peer relationship assessment; and (ii) parental and grandparental measures to assess personality and dynamics within families. We welcome interest in our study and ask investigators to contact the corresponding author for additional information on data acquisition.

Background: Still considered one of the most prevalent nutritional problems in the world, anemia has been shown in many studies to have deleterious effects on neurobehavioral development. While most research efforts have focused on investigating the effects of anemia on social and emotional development of infants by using a cross-sectional design, research is still needed to investigate whether early childhood anemia, beyond infantile years, is linked with behavioral problems. Objective: This study assessed whether (1) hemoglobin (Hb) levels in early childhood are associated with externalizing behavior; and (2) this relationship is confounded by social adversity. Methods: Hemoglobin levels were taken from children (N = 98) of the China Jintan Cohort Study at age 4 years, and externalizing behaviors (attention and aggression) were assessed with the Child Behavior Checklist (ASEBA-CBCL) at age 6 years (mean age 5.77 ± 0.39 years old). Results: Compared with other children in the sample, children with relatively lower Hb levels at age 4 had more behavioral problems in both attention and aggression at age 6, independent of social adversity. For boys, this association was significant for attention problems, which did not interact with social adversity. For girls, the association was significant for aggression, which interacted with social adversity. While girls on average exhibited higher social adversity than boys, the main effect of Hb was only significant in girls with low social adversity. Conclusions: These results indicate that there is an inverse association between hemoglobin levels and later behavioral problems. Findings of this study suggest that regular monitoring of children’s hemoglobin levels and appropriate intervention may help with early identification of behavioral problems.