Chonghuai Yan

Sleep and Obesity in Preschool Children

OBJECTIVE To examine the relationship between sleep and obesity in children 3 to 4 years old in Shanghai, China. STUDY DESIGN A total of 1311 Chinese children from 10 kindergarten classes in Shanghai, aged 3 to 4 years, who were participating in the kindergarten entrance health examination in 2000, were included in the study. Body weight and height were measured, and a questionnaire was given to the childrens parents about sleep and physical and social characteristics of the children and their family. The main outcome measure was obesity, defined as body mass index (kg/m2) > or = 95th percentile for the children. RESULTS Compared with children reporting > or = 11 hours of sleep per night, the odds ratio for childhood obesity was 4.76 (95% CI, 1.28-17.69) for children with <9 hours of sleep, and 3.42 (95% CI, 1.12-10.46) for children with 9.0 to 9.4 hours of sleep, after adjustment for age, sex, and other risk factors. Children with caregivers who slept less, who had mothers with higher education, or who co-slept with caregivers had less nighttime sleep than other children. CONCLUSION Short sleep duration is positively associated with obesity in preschool children, and short nighttime sleep duration is significantly related to bedtime and co-sleeping with caregivers.

Sleep, school performance, and a school-based intervention among school-aged children: a sleep series study in China.

Background Sufficient sleep during childhood is essential to ensure a transition into a healthy adulthood. However, chronic sleep loss continues to increase worldwide. In this context, it is imperative to make sleep a high-priority and take action to promote sleep health among children. The present series of studies aimed to shed light on sleep patterns, on the longitudinal association of sleep with school performance, and on practical intervention strategy for Chinese school-aged children. Methods and Findings A serial sleep researches, including a national cross-sectional survey, a prospective cohort study, and a school-based sleep intervention, were conducted in China from November 2005 through December 2009. The national cross-sectional survey was conducted in 8 cities and a random sample of 20,778 children aged 9.0±1.61 years participated in the survey. The five-year prospective cohort study included 612 children aged 6.8±0.31 years. The comparative cross-sectional study (baseline: n = 525, aged 10.80±0.41; post-intervention follow-up: n = 553, aged 10.81±0.33) was undertaken in 6 primary schools in Shanghai. A battery of parent and teacher reported questionnaires were used to collect information on children’s sleep behaviors, school performance, and sociodemographic characteristics. The mean sleep duration was 9.35±0.77 hours. The prevalence of daytime sleepiness was 64.4% (sometimes: 37.50%; frequently: 26.94%). Daytime sleepiness was significantly associated with impaired attention, learning motivation, and particularly, academic achievement. By contrast, short sleep duration only related to impaired academic achievement. After delaying school start time 30 minutes and 60 minutes, respectively, sleep duration correspondingly increased by 15.6 minutes and 22.8 minutes, respectively. Moreover, intervention significantly improved the sleep duration and daytime sleepiness. Conclusions Insufficient sleep and daytime sleepiness commonly existed and positively associated with the impairment of school performance, especially academic achievement, among Chinese school-aged children. The effectiveness of delaying school staring time emphasized the benefits of optimal school schedule regulation to children’s sleep health.

Prevalence and risk factors of childhood allergic diseases in eight metropolitan cities in China: a multicenter study.

BackgroundSeveral studies conducted during the past two decades suggested increasing trend of childhood allergic diseases in China. However, few studies have provided detailed description of geographic variation and explored risk factors of these diseases. This study investigated the pattern and risk factors of asthma, allergic rhinitis and eczema in eight metropolitan cities in China.MethodsWe conducted a cross-sectional survey during November-December 2005 in eight metropolitan cities in China. A total of 23791 children aged 6-13 years participated in this survey. Questions from the standard questionnaire of the International Study of Asthma and Allergies in Children (ISAAC) were used to examine the pattern of current asthma, allergic rhinitis and eczema. Logistic regression analyses were performed to assess the risk factors for childhood allergies.ResultsThe average prevalence of childhood asthma, allergic rhinitis and eczema across the eight cities was 3∙3% (95% Confidence interval (CI): 3∙1%, 3∙6%), 9∙8% (95% CI: 9∙4%, 10∙2%) and 5∙5% (95% CI: 5∙2%, 5∙8%), respectively. Factors related to lifestyle, mental health and socio-economic status were found to be associated with the prevalence of childhood allergies. These risk factors were unevenly distributed across cities and disproportionately affected the local prevalence.ConclusionsThere was apparent geographic variation of childhood allergies in China. Socio-environmental factors had strong impacts on the prevalence of childhood allergies; but these impacts differed across regions. Thus public health policies should specifically target at the local risk factors for each individual area.

Habitual Snoring in school-aged children: environmental and biological predictors

BackgroundHabitual snoring, a prominent symptom of sleep-disordered breathing, is an important indicator for a number of health problems in children. Compared to adults, large epidemiological studies on childhood habitual snoring and associated predisposing factors are extremely scarce. The present study aimed to assess the prevalence and associated factors of habitual snoring among Chinese school-aged children.MethodsA random sample of 20,152 children aged 5.08 to 11.99 years old participated in a cross-sectional survey, which was conducted in eight cities of China. Parent-administrated questionnaires were used to collect information on childrens snoring frequency and the possible correlates.ResultsThe prevalence of habitual snoring was 12.0% (14.5% for boys vs. 9.5% for girls) in our sampled children. Following factors were associated with an increased risk for habitual snoring: lower family income (adjusted odds ratio [OR] = 1.46), lower fathers education (OR = 1.38 and 1.14 for middle school or under and high school of educational level, respectively), breastfeeding duration < 6 months (OR = 1.17), pregnancy maternal smoking (OR = 1.51), obesity (OR = 1.50), overweight (OR = 1.35), several respiratory problems associated with atopy and infection, such as chronic/allergic rhinitis (OR = 1.94), asthma (OR = 1.43), adenotonsillar hypertrophy (OR = 2.17), and chronic otitis media (OR = 1.31), and family history of habitual snoring (OR = 1.70).ConclusionThe prevalence of habitual snoring in Chinese children was similar to that observed in other countries. The potential predisposing factors covered socioeconomic characteristics, environmental exposures, chronic health problems, and family susceptibility. Compared to socioeconomic status and family susceptibility, environmental exposures and chronic health problems had greater impact, indicating childhood habitual snoring could be partly prevented by health promotion and environmental intervention.

Personal characteristics related to the risk of adolescent internet addiction: a survey in Shanghai, China

BackgroundParalleling the rapid growth in computers and internet connections, adolescent internet addiction (AIA) is becoming an increasingly serious problem, especially in developing countries. This study aims to explore the prevalence of AIA and associated symptoms in a large population-based sample in Shanghai and identify potential predictors related to personal characteristics.MethodsIn 2007, 5,122 adolescents were randomly chosen from 16 high schools of different school types (junior, senior key, senior ordinary and senior vocational) in Shanghai with stratified-random sampling. Each student completed a self-administered and anonymous questionnaire that included DRM 52 Scale of Internet-use. The DRM 52 Scale was adapted for use in Shanghai from Young’s Internet Addiction Scale and contained 7 subscales related to psychological symptoms of AIA. Multiple linear regression and logistic regression were both used to analyze the data.ResultsOf the 5,122 students, 449 (8.8%) were identified as internet addicts. Although adolescents who had bad (vs. good) academic achievement had lower levels of internet-use (p < 0.0001), they were more likely to develop AIA (odds ratio 4.79, 95% CI: 2.51-9.73, p < 0.0001) and have psychological symptoms in 6 of the 7 subscales (not in Time-consuming subscale). The likelihood of AIA was higher among those adolescents who were male, senior high school students, or had monthly spending >100 RMB (all p-values <0.05). Adolescents tended to develop AIA and show symptoms in all subscales when they spent more hours online weekly (however, more internet addicts overused internet on weekends than on weekdays, p < 0.0001) or when they used the internet mainly for playing games or real-time chatting.ConclusionsThis study provides evidence that adolescent personal factors play key roles in inducing AIA. Adolescents having aforementioned personal characteristics and online behaviors are at high-risk of developing AIA that may compound different psychological symptoms associated with AIA. Spending excessive time online is not in itself a defining symptom of AIA. More attention is needed on adolescent excessive weekend internet-use in prevention of potential internet addicts.

Case-only study of interactions between DNA repair genes (hMLH1, APEX1, MGMT, XRCC1 and XPD) and low-frequency electromagnetic fields in childhood acute leukemia

A case-only study was conducted in 123 patients with sporadic acute leukemia (AL). The locations of electric transformers and power lines were noted in each area, and their distances from the houses of the study patients were measured. The intensities of magnetic fields (B) were measured in 66 cases. Unconditional logistic regression analysis was performed adjusting for age, gender, parental education and occupation, indoor and outdoor pesticides use, presence of television sets, refrigerators and microwave ovens in childrens rooms and the presence of chemical factories or telecommunication transmitters within 500 m of the houses. The results of the gene–environment analyses revealed that an interaction existed between the XRCC1 Ex9 + 16 A allele and the presence of electric transformers and power lines within 100 m (Mean B = 0.14 μTeslas, μT) of the houses (interaction odds ratio, COR = 4.31, 95%CI: 1.54–12.08). The COR for the interaction of XRCC1 Ex9 + 16A and the presence of these installations within 50 m (Mean B = 0.18 μT) of the houses was 4.39 (95%CI: 1.42–13.54). Our results suggest a possible association between electric transformers and power lines and the XRCC1 Ex9 + 16A allele in patients with childhood AL.

The national trend of blood lead levels among Chinese children aged 0-18 years old, 1990-2012.

We analyzed the epidemiological data during 1990-2012 that investigated the blood lead level (BLL) in the population aged 0-18 years old in China mainland and provided evidence of the benefits of implementing policies to prevent lead pollution based on the dynamic changes of BLL. Data were collected through databases including China Knowledge Resource Integrated Database (CNKI), CBM disc, Wanfang Data, Pubmed and Medline. The inclusion criteria were: 1. Epidemiological study in healthy population not included studies limited to specific patient; 2. Study subject was not the specific lead exposure population; 3. Sample size should be no less than 100 (for neonatal, no less than 50); 4. BLL detection was under strict quality control; and 5. Results should be presented as BLL (arithmetic mean level or geometric mean level). 62 articles were included in this study. All the surveys in these articles contained 189,352 subjects in 19 provinces, autonomous regions and municipalities. Linear regression analysis showed a significant decrease between 1990 and 2012 with an estimated regression coefficient of 3.05/year (SE=0.01, p<0.001). BLL gradually declined since early 21st century. Median levels of BLL among the three economic zones were 51.4 μg/L in the eastern zone, 52.72 μg/L in the central zone and 46.2 μg/L in the western zone respectively. Median BLLs in male and female population aged 0-18 years old of China were 48.8 μg/L and 46.1μg/L. Median levels of BLL among the different age ranges were 74.9 μg/L in newborn, 46.4 μg/L in 0 to 3 years old, 57.6 μg/L in 3 to 7 years old and 55.6 μg/L in above 7 years old respectively. In conclusion, the BLL in the Chinese population of 0-18 years old has gradually dropped in the past 10 years. The decline in temporal trend still remains under potential impacts of several factors such as economical level, gender and age difference. Although, China has made significant achievements in the control prevention of lead pollution, concerted efforts are still warranted to reduce children lead poisoning.

Childhood lead poisoning in China: challenges and opportunities.

It is well known that children < 7 years of age are uniquely susceptible to lead poisoning because of their constant hand-to-mouth behaviors, their immature central nervous systems, and their rapidly developing bodies (Gavaghan 2002; Lanphear et al. 2005; Shen 1996; Tong et al. 1996, 1998). Although exposure to lead has decreased in many countries, significant concerns remain about continued exposure of children to lead. From the end of the 1990s through 2009, China’s average blood lead levels in urban children 0–6 years of age decreased from 7–10 µg/dL to 2.5–6 µg/dL (Peng et al. 2011; Qi et al. 2002). The prevalence of children with higher blood lead levels (≥ 10 µg/dL) decreased from 30–50% to 1.5–15% (Luo et al. 2011; Xiong et al. 2011). The decline in blood lead levels appears to be associated with national efforts to decrease lead pollution, including the phaseout of leaded gasoline; a transition from coal fuel to diesel, natural gas, and other clean energy alternatives; and closing or merging heavily polluted enterprises. In addition, many lead-polluting industries have migrated from large cities to middle-size and small cities and to rural areas, often from eastern China to western China. However, there has also been a rapid development of automobile and information industries and an increased demand for lead-acid batteries in China during the last decade. China has also experienced a significant expansion in galena mining, lead smelting, battery production and recycling, e-waste disassembly and recycling, metal processing, production of lead-containing chemicals, cable manufacturing, and production of wire rope. In addition, there has been a substantial increase in the number of small family businesses that use lead-containing products. Although an overall decline in children’s blood lead levels has been observed over in years, children’s exposure to lead is still common in many Chinese cities. Industrial pollution is clearly one of the most important causes of lead poisoning among children in China. However, other significant sources of exposure may cause lead poisoning in children. For example, young children may ingest or swallow toys or other items or prescribed medicines containing lead. Some lead compounds, including lead tetraoxide (red lead), lead monoxide (yellow lead), and basic lead carbonate are used in folk remedies for convulsions and carbuncles and as astringents. Many cases of clinical lead poisoning are caused by topical or oral administration of lead-containing compounds in the treatment of vitiligo, eczema, epilepsy, diarrhea, cough, asthma, oral diseases, and intestinal parasites. In some areas of China, newborns or infants are still treated with red or yellow lead powder for skin care, either with lead powder alone or powder mixed with commercially available talcum powder. Lead poisoning in children can also be caused by using lead powder to treat mouth ulcers. Sometimes cooking wine or water stored in lead-containing pots is used to prepare food or reconstitute milk power, which can result in significant exposure to lead. At the present time, blood lead screening is the only effective way to identify lead-poisoned children. Every year, tens of thousands children are screened in China, and a considerable number of children with elevated blood lead and lead poisoning are identified. However, screening for blood lead level occurs typically in response to requests from parents and not as part of an overall examination. Thus, a large number of children may have lead poisoning that is undetected, and therefore they do not receive timely diagnosis and treatment. Unfortunately, pediatricians can misdiagnose or overlook cases of lead poisoning because they lack training in the prevention and treatment of childhood lead poisoning. At the present time, a number of policies and measures could be implemented to promote the prevention and control of childhood lead poisoning in China. Regulatory policies need to be put in place to reduce lead emissions from numerous lead-related industries. There is a need to develop new and renewable energy sources, including wind, solar, water, and nuclear power; reduce coal consumption; and attenuate air pollution from the thermo-power–generation process. There is a need to improve quality control systems for blood lead screening and blood lead testing; promote nationwide implementation of unified blood lead testing techniques and methods; and increase the overall implementation of blood lead testing in primary health care settings. Every child ≤ 6 years of age should have the opportunity to receive blood lead testing. For children living in lead-contaminated areas, special screening programs should also be developed. Finally, the public and pediatricians in China need to be educated about the prevention and treatment of childhood lead poisoning. The experience of China, the United States, and other countries supports the idea that childhood lead poisoning is preventable. Although significant improvement has occurred in China over the last 20 years, many challenges remain. Coordinated and sustained efforts will be required to lessen the impact of exposure to lead on Chinese children now and in the future.

Determinants of urinary 8-hydroxy-2'-deoxyguanosine in Chinese children with acute leukemia.

The 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG), an oxidized nucleoside of DNA, not only is a widely used biomarker for the measurement of endogenous oxidative DNA damage, but might also be a risk factor for many diseases including cancer. Elevated level of urinary 8‐OHdG has been detected in patients with various malignancies. In the present study, the level of urinary 8‐OHdG was examined in 116 Chinese children with acute leukemia (94 acute lymphoid leukemia, ALL, 22 acute myeloid leukemia, AML), and its correlation with urinary metal elements was investigated. Our result showed that the level of urinary 8‐OHdG in children with acute leukemia before treatment was significantly elevated compared with that in normal controls (11.92 ± 15.42 vs. 4.03 ± 4.70 ng/mg creatinine, P < 0.05). In particular, urinary 8‐OHdG was higher in children with acute leukemia aged under 3 years (20.86 ± 21.75 ng/mg creatinine) than in those aged 3–15 years (8.09 ± 9.65 ng/mg creatinine), whereas no differences were shown in terms of gender, parental smoking and education, household income, place of residence, and use of paracetamol. In addition, urinary 8‐OHdG levels were similar among different subtypes of acute lymphoid leukemia (ALL) patients. Furthermore, linear regression analysis revealed a significant correlation between urinary 8‐OHdG and urinary Cr, but not Fe or As, in group aged <3 years compared with group aged 3–15 years (P = 0.041), indicating that the metal elements may be involved in increasing urinary 8‐OHdG level in younger children with acute leukemia. Our results suggest that children with acute leukemia undergo an increased risk of oxidative DNA damage, which may be correlated with high level of Cr exposure in Chinese children with acute leukemia.

Effects of duration and timing of prenatal stress on hippocampal myelination and synaptophysin expression.

The relationship between prenatal stress (PS) exposure and neurodevelopmental deficits remains inconclusive, especially when assessing the role of PS duration and timing and sex-dependent effects. This study explored a sex-specific association between the duration and timing of exposure and the outcomes of PS-induced neurotoxicity in hippocampal microstructure, synaptophysin expression, and neurobehavioral performance in rats. Pregnant rats were randomly assigned to control, PS-ML (exposed to prenatal restraint stress in the mid-to-late period of pregnancy), or PS-L (exposed in the late period of pregnancy) groups, and offspring in each group were divided into two subgroups by sex. Surface-righting reflex test, cliff avoidance test and Morris water maze test showed that neurodevelopmental levels were reduced in PS-treated pups but without significant sex differences. On postnatal day 22, hippocampal microstructure was examined by electron microscopy, and the expression of hippocampal synaptophysin was assessed by western blot. Abnormal ultrastructural appearance of hippocampal neurons and myelin sheaths, more degenerating neurons and higher G-ratios were found in young PS-ML and PS-L rats as well as reduced expression of hippocampal synaptophysin, although PS-ML pups were more greatly affected than PS-L, with males showing slightly greater impairments than females. These findings suggest that hippocampal hypo-myelination and decreased synaptophysin expression in neurodevelopment may be a duration and time-dependent effect of prenatal stress exposure, modified slightly by sex.