Blood lead levels and associated factors among children in Guiyu of China: a population-based study

Prevalence and risk factors of elevated blood lead levels in 0-6-year-old children: a national cross-sectional study in China

Aims

To evaluate the prevalence and risk factors of elevated blood lead levels (EBLL) among the pediatric population in China.

Methods

Questionnaire investigation about Lead exposure information, venous blood samples collection and BLL detection are conducted. A total of 32,543 subjects aged 0-6 years old (from 1 month old to under 7 years old) were recruited from May 2013 to March 2015 in 15 provinces of China.

Results

The overall weighted prevalence of EBLL which is defined as BLL ≥ 50 μg/L in this study is 4.1%, as for different geographical regions, with lowest prevalence in the western region of China, lowest prevalence in Shaanxi province and highest in Hebei province. In 0-3-Year-old children, female weighted prevalence of EBLL (4.0%) is higher than male (2.4%), while in 3-6-Year-old children, male (8.3%) is higher than female (6.3%). Bad hygienic habits, some kind of custom, using folk prescriptions, living on the ground floor, poor drinking water quality, indoor air pollution and passive smoking exposure remain risk factors of EBLL (BLL ≥ 50 μg/L) of 0-6-year-old (from 1 month old to under 7 years old) children in China, after adjustment of gender, age, geographical region, annual household income, educational background and occupation of the parents and caregivers.

Conclusion

This study reveals the prevalence and risk factors for EBLL (BLL ≥ 50 μg/L) in 0-6-Year-old Children of China. We hope this study will help public health education and inform policy for preventing and eradicating children's lead poisoning in China.

Health risk assessment of workers exposed to lead dust in informal e-waste recycling workshops

Informal recycling of electronic waste (e-waste) has attracted significant attention due to its economic benefits and rapid growth rate in many parts of the world. Unfortunately, unsafe conditions of recycling workshops possess chronic exposure to workers and lead to elevated blood lead concentrations (BLCs). Upon measuring the lead concentration in the dust of recycling workshops and the e-wastes in southwestern region of Iran, the related health risks were assessed in 30 exposed workers and 30 non-exposed habitants cases based on the determination of BLC. The average BLCs in exposed workers and non-exposed habitants cases were 24 μg/dL and 7 μg/dL, respectively. The geo-accumulation index (Igeo) revealed heavy contamination of dust in informal e-waste recycling workshops (IERWs) (5023 μg/kg) and significantly lower levels in unexposed areas (49 μg/kg). Health risk assessment indicated that lead exposure from IERWs appears to be a potential threat to workers and indirectly to their families.

Blood lead levels of children exposed to e-waste: a systematic review and meta-analysis

Blood lead levels (BLLs) have been decreasing worldwide for decades. However, systematic reviews and quantitative syntheses of BLLs in electronic waste (e-waste)-exposed children are lacking. To summarize temporal trend of BLLs among children in e-waste-recycling areas. Fifty-one studies met the inclusion criteria and included participants from six countries. Meta-analysis was performed using the random-effects model. Results showed that among e-waste-exposed children, the total geometric mean (GM) BLL was 7.54 μg/dL (95% CI: 6.77, 8.31). Children's BLLs displayed a decreasing temporal trend, from 11.77 μg/dL in phase I (2004-2006) to 4.63 μg/dL in phase V (2016-2018). Almost 95% of eligible studies found that children exposed to e-waste had significantly higher BLLs than reference groups. The difference of children's BLLs between the exposure group and the reference group was from 6.60 μg/dL (95% CI: 6.14, 7.05) in 2004 to 1.99 μg/dL (95% CI: 1.61, 2.36) in 2018. For subgroup analyses, except for Dhaka and Montevideo, the BLLs of children from Guiyu in the same survey year were higher than those of children from other regions. Our findings indicate that the gap between BLLs of children exposed to e-waste and those of reference group children is closing, and we appeal that the critical value for blood lead poisoning in children should be lowered in key e-waste-dismantling areas of developing countries, such as Guiyu.

Understanding Environmental Pollutions of Informal E-Waste Clustering in Global South via Multi-Scalar Regulatory Frameworks: A Case Study of Guiyu Town, China

The recycling of e-waste by the informal sector has brought countries in the Global South raw materials (e.g. metals and plastics), second-hand electronic equipment and components, and economic opportunities in conjunction with appalling environmental pollutions and health problems. Despite the longstanding international and national legislation regulating transnational trade and domestic recycling, informal e-waste economies are still clustering in many Global South countries. This study offers historically and geographically specific explanations of this conundrum, by interrogating the multi-scalar regulatory frameworks in which the informal e-waste economies and their pollutions are embedded, by drawing on China, particularly the former global e-waste hub-Guiyu town, as the case study. We argue that the contested and problematic application of current international and national legislation in regulating e-waste is in part pertaining to the slippery definition of what counts as “e-waste” and its paradoxical nature as both resources and pollutants. At the global scale, trajectories of global e-waste flows are shaped by the multitude of loopholes, contradictions and ambiguous articles left by the Basel Convention and by different countries’ disparate attitudes towards the e-waste trade. At the national scale, the ambiguities and contradictions in the Basel Convention have been passed on to and shaped China’s national e-waste regulatory frameworks. China’s equivocal legislation, paradoxical attitude, and formal enterprises’ weak competence contribute to the rise of informal e-waste recycling in Guiyu. Yet, China’s e-waste regime has been greatly restructured within the past decade, with formal recycling enterprises playing an increasingly significant role.

The Social Cost of Informal Electronic Waste Processing in Southern China

Large amounts of e-waste are processed “informally” in lower income countries. Such processing releases dangerous pollutants, which increase mortality and reduce cognitive functioning. This paper estimates the social cost of informal e-waste processing in Southern China. This parameter may be “plugged-in” to cost-benefit analyses that evaluate the economic efficiency of policies to reduce informal e-waste processing in China or other lower income countries. It may also be used in the estimation of the social benefits (or costs) of new or proposed e-waste processing policies in higher income countries. We estimate that the social cost of informal e-waste processing in Guiyu is about $529 million. This amount is equivalent to about $423 per tonne (in 2018 US dollars) or $3528 per person, which is over half the gross income per capita of the residents of Guiyu. We also perform sensitivity analysis that varies the estimated mortality outcomes, the value of a statistical life and the amount of e-waste processed.

A Diagnostic Prediction Model of Acute Symptomatic Portal Vein Thrombosis

BACKGROUND

The aim of this study was to develop a diagnostic prediction model to improve identification of acute symptomatic portal vein thrombosis (PVT).

METHODS

We examined 47 patients with PVT and 94 controls without PVT in the Second Affiliated Hospital of Soochow University and Suqian People's Hospital of Nanjing, Gulou Hospital Group. We constructed a prediction model by using a support vector machine (SVM) classifier coupled with a least absolute shrinkage and selection operator (LASSO). We applied a 10-fold cross-validation to estimate the error rate for each model.

RESULTS

The present study indicated that acute symptomatic PVT was associated with 11 indicators, including liver cirrhosis, D-Dimer, splenomegaly, splenectomy, inherited thrombophilia, ascetic fluid, history of abdominal surgery, bloating, C-reactive protein (CRP), albumin, and abdominal tenderness. The LASSO-SVM model achieved a sensitivity of 91.5% and a specificity of 100.0%.

CONCLUSIONS

We developed a LASSO-SVM model to diagnose PVT. We demonstrated that the model achieved a sensitivity of 91.5% and a specificity of 100.0%.

Childhood lead poisoning in Gaza Strip, the Palestinian Authority

PURPOSE

To assess lead poisoning among a pediatric population in Gaza Strip, the Palestinian Authority.

METHODS

A total of 1705 questionnaires and blood samples were collected from children aged 2-6 years, by the finger stick capillary procedure, for the assessment of blood lead level (BLL), using the LeadCare kits. The samples were collected from children living close to lead processing units (hotspots) and far 100-500 m away (general population). Management of elevated BLL was achieved by gavage of chelating agent d-penicillamine at a dose of 30 mg kg^-1 body weight/day for two weeks for children having BLL above 20 μg/dl. Data were statistically analyzed using SPSS computer program version 22.

RESULTS

Distribution of children in Gaza Strip by sampling process illustrated those 326 children (19.1%) living in lead processing units (hot spots) and 1379 children (80.9%) from location far away 100-500 m from host spot (general population). The mean BLL was 10.4 μg/dl. A total of 440 children (25.8%) were found to be having BLL ≥ 10 μg/dl while 1265 children (74.2%) have BLL < 10 μg/dl. BLL < 10 μg/dl was taken as a cut point due to CDC standards. The prevalence of BLL in hotspot areas in children who were exposed to lead and have BLL ≥ 10 μg/dl was 95.7% while in general population it was 9.3%. The difference between the study population was statistically significant (p < 0.01). Statistical significant differences between the study populations were found among several independent variables of risk factors such as household location and exposure sources, and occupational exposure. Gavage of d-penicillamine significantly reduced BLL to the acceptable level (BLL < 10 μg/dl).

CONCLUSIONS

Childhood lead poisoning accounts for a substantial burden in Gaza Strip. Hotspots of lead-related industries are the high risk areas that contributing to high BLLs in children. d-Penicillamine was effective in the treatment of lead poisoning among children. Health education and treatment campaigns should be designed to minimize or prevent childhood lead poisoning in Gaza Strip.

Differential DNA methylation in newborns with maternal exposure to heavy metals from an e-waste recycling area

This study explored the effects of maternal exposure to e-waste environmental heavy metals on neonatal DNA methylation patterns. Neonatal umbilical cord blood (UCB) samples were collected from participants that resided in an e-waste recycling area, Guiyu and a nearby non-e-waste area, Haojiang in China. The concentrations of UCB lead (Pb), cadmium (Cd), manganese (Mn) and chromium (Cr) were measured by graphite furnace atomic absorption spectrometry. Epigenome-wide DNA methylation at 473, 844 CpG sites (CpGs) were assessed by Illumina 450 K BeadChip. The differential methylation of CpG sites from the microarray were further validated by bisulfite pyrosequencing. Bioinformatics analysis showed that 125 CpGs mapped to 79 genes were differential methylation in the e-waste exposed group with higher concentrations of heavy metals in neonatal UCB. These genes mainly involve in multiple biological processes including calcium ion binding, cell adhesion, embryonic morphogenesis, as well as in signaling pathways related to NFkB activation, adherens junction, TGF beta and apoptosis. Among them, BAI1 and CTNNA2 (involving in neuron differentiation and development) were further verified to be hyper- and hypo-methylated, respectively, which were associated with maternal Pb exposure. These results suggest that maternal exposure to e-waste environmental heavy metals (particularly lead) during pregnancy are associated with peripheral blood differential DNA methylation in newborns, specifically the genes involving in brain neuron development.

Protective Effects of Dietary Supplements Containing Probiotics, Micronutrients, and Plant Extracts Against Lead Toxicity in Mice

Lead (Pb) intoxication is a serious food safety issue, and the development of relevant dietary strategies is an area of ongoing research. In this study, two different dietary supplements were designed and evaluated for their effects against Pb toxicity in mice. Dietary supplement A contained grape seed extract, tea polyphenols and Lactobacillus plantarum CCFM8661, and dietary supplement B contained vitamin C, calcium carbonate, zinc acetate, and L. plantarum CCFM8661. The results showed that both dietary supplements could effectively decrease Pb levels, protect aminolevulinic acid dehydratase, superoxide dismutase and catalase activities and recover glutathione, zinc protoporphyrin and malondialdehyde levels in tissues and blood of mice. A step-through passive avoidance task confirmed that the dietary supplements could recover the learning and memory capacities of Pb-exposed mice. The protective effects of both dietary supplements to alleviate oxidative stress and cognitive impairments were superior to the chelator treatment. Administration of the dietary supplements during Pb exposure offered more significant protection than administration after Pb exposure. Animal safety evaluation also indicated that these dietary supplements barely induced side effects in the mice. This study provides evidence that dietary supplements containing probiotics, micronutrients, and plant extracts can be considered a new dietary strategy against Pb toxicity.

Prevention-intervention strategies to reduce exposure to e-waste

As one of the largest waste streams, electronic waste (e-waste) production continues to grow in response to global demand for consumer electronics. This waste is often shipped to developing countries where it is disassembled and recycled. In many cases, e-waste recycling activities are conducted in informal settings with very few controls or protections in place for workers. These activities involve exposure to hazardous substances such as cadmium, lead, and brominated flame retardants and are frequently performed by women and children. Although recycling practices and exposures vary by scale and geographic region, we present case studies of e-waste recycling scenarios and intervention approaches to reduce or prevent exposures to the hazardous substances in e-waste that may be broadly applicable to diverse situations. Drawing on parallels identified in these cases, we discuss the future prevention and intervention strategies that recognize the difficult economic realities of informal e-waste recycling.

Surface display of PbrR on Escherichia coli and evaluation of the bioavailability of lead associated with engineered cells in mice

Human exposure to lead mainly occurs by ingestion of contaminated food, water and soil. Blocking lead uptake in the gastrointestinal tract is a novel prevention strategy. Whole-cell biosorbent for lead was constructed with PbrR genetically engineered on the cell surface of Escherichia coli (E. coli), a predominant strain among intestinal microflora, using lipoprotein (Lpp)-OmpA as the anchoring protein. In vitro, the PbrR displayed cells had an enhanced ability for immobilizing toxic lead(II) ions from the external media at both acidic and neutral pH, and exhibited a higher specific adsorption for lead compared to other physiological two valence metal ions. In vivo, the persistence of recombinant E. coli in the murine intestinal tract and the integrity of surface displayed PbrR were confirmed. In addition, oral administration of surface-engineered E. coli was safe in mice, in which the concentrations of physiological metal ions in blood were not affected. More importantly, lead associated with PbrR-displayed E. coli was demonstrated to be less bioavailable in the experimental mouse model with exposure to oral lead. This is reflected by significantly lower blood and femur lead concentrations in PbrR-displayed E. coli groups compared to the control. These results open up the possibility for the removal of toxic metal ions in vivo using engineered microorganisms as adsorbents.

Blood Lead Level in Children with Neurological Disorders

OBJECTIVE

We aimed to investigate the blood lead level (BLL) in children with neurologic disorders of unknown causes and compare with normal children.

MATERIALS & METHODS

In this prospective case-control study, 68 patients aged 1 to 18 yr with neurologic disorders of unknown causes, were referred to pediatric neurology clinics and wards, Shiraz, Iran selected during a 12 months period from Sep 2013. They were compared with 1:1 ratio, age, and sex-matched healthy children. BLL was checked from all participants using 3 cc heparinized venous blood sample. Level of ≥5 mcg/dl was considered toxic dose.

RESULTS

Totally, 136 children (68 cases and 68 controls) with mean ages of 5.20±4.12 and 4.18±3.86 yr, respectively, were enrolled. Mean BLL was higher in case group than in controls but the difference was not significant (P=0.84), though they were less than toxic levels in both. In addition, the difference in mean BLLs was not significant in terms of living place, sex, and age. Totally, 17.7% of the study sample had BLL ≥5 mcg/dl. The frequency of BLL ≥5 mcg/dl was significantly higher in case group (P=0.024) with an odds ratio 2.9 times higher (95% CI: 1.066-7.60).

CONCLUSION

Strategies in public health must focus on practicing primary and secondary preventions of lead exposure in children.

Elevated lead levels from e-waste exposure are linked to decreased olfactory memory in children

Lead (Pb) is a developmental neurotoxicant and can cause abnormal development of the nervous system in children. Hence, the aim of this study was to investigate the effect of Pb exposure on child olfactory memory by correlating the blood Pb levels of children in Guiyu with olfactory memory tests. We recruited 61 preschool children, 4- to 7-years of age, from Guiyu and 57 children from Haojiang. The mean blood Pb level of Guiyu children was 9.40 μg/dL, significantly higher than the 5.04 μg/dL mean blood Pb level of Haojiang children. In addition, approximately 23% of Guiyu children had blood Pb levels exceeding 10.00 μg/dL. The correlation analysis showed that blood Pb levels in children highly correlated with e-waste contact (r_s = 0.393). Moreover, the mean concentration of serum BDNF in Guiyu children (35.91 ng/ml) was higher than for Haojiang (28.10 ng/ml) and was positively correlated with blood Pb levels. Both item and source olfactory memory tests at 15 min, 5 h and 24 h after odor exposure showed that scores were lower in Guiyu children indicative of reduced olfactory memory in Guiyu children. Olfactory memory tests scores negatively correlated with blood Pb and serum BDNF levels, but were positively associated with parental education levels. At the same time, scores of both tests on children in the high blood Pb level group (blood Pb levels > 5.00 μg/dL) were lower than those in the low blood Pb level group (blood Pb levels ≤ 5.00 μg/dL), implying that Pb exposure decreases olfactory memory in children. Our findings suggest that Pb exposure in e-waste recycling and dismantling areas could result in an increase in serum BDNF level and a decrease in child olfactory memory, in addition, BDNF might be involved in olfactory memory impairment.

'Away' is a place: The impact of electronic waste recycling on blood lead levels in Ghana

E-waste recycling remains a major source of livelihood for many urban poor in developing countries, but this economic activity is fraught with significant environmental health risk. Yet, human exposure to the toxic elements associated with e-waste activities remains understudied and not evidently understood. This study investigates the impact of informal e-waste processing on the blood lead levels (BLLs) of e-waste workers and non-e-waste workers (mainly females working in activities that serve the Agbogbloshie e-waste site), and relates their lead exposure to socio-demographic and occupational characteristics. A total of 128 blood samples were analysed for lead levels. Surprisingly, the mean BLL (3.54μg/dL) of non-e-waste workers was slightly higher than that of e-waste workers (3.49μg/dL), although higher BLLs ranges were found among e-waste workers (0.50-18.80μg/dL) than non-e-waste workers (0.30-8.20μg/dL). Workers who engaged in e-waste burning tended to have the highest BLLs. In general, the BLLs are within the ABLES/US CDC reference level of 5μg/dL, although 12.3% of the workers have elevated BLLs, i.e. BLL ≥5μg/dL. The study concludes that the impact of e-waste recycling is not limited to workers alone. Traders and residents within the Agbogbloshie enclave are equally at risk through a range of environmental vectors. This calls for increased public awareness about the effects of human exposure to lead and other toxic elements from e-waste recycling. A key contribution is that government and stakeholder projects for safe e-waste infrastructure should disaggregate the e-waste value chain, recognize differential risk and resist one-size-fits-all strategies.

Alteration of the number and percentage of innate immune cells in preschool children from an e-waste recycling area

Heavy metal lead (Pb) and cadmium (Cd) are widespread environmental contaminants and exert detrimental effects on the immune system. We evaluated the association between Pb/Cd exposures and innate immune cells in children from an electronic waste (e-waste) recycling area. A total number of 294 preschool children were recruited, including 153 children from Guiyu (e-waste exposed group), and 141 from Haojiang (reference group). Pb and Cd levels in peripheral blood were measured by graphite furnace atomic absorption spectrophotometer, NK cell percentages were detected by flow cytometer, and other innate immune cells including monocytes, eosinophils, neutrophils and basophils were immediately measured by automated hematology analyzer. Results showed children in Guiyu had significantly higher Pb and Cd levels than in reference group. Absolute counts of monocytes, eosinophils, neutrophils and basophils, as well as percentages of eosinophils and neutrophils were significantly higher in the Guiyu group. In contrast, NK cell percentages were significantly lower in Guiyu group. Pb elicited significant escalation in counts of monocytes, eosinophils and basophils, as well as percentages of monocytes, but decline in percentages of neutrophils in different quintiles with respect to the first quintile of Pb concentrations. Cd induced significant increase in counts and percentages of neutrophils in the highest quintile compared with the first quintile of Cd concentrations. We concluded alteration of the number and percentage of innate immune cells are linked to higher levels of Pb and Cd, which indicates Pb and Cd exposures might affect the innate and adaptive immune response in Guiyu children.

Elevated lead levels and changes in blood morphology and erythrocyte CR1 in preschool children from an e-waste area

Improper dismantling and combustion of electronic waste (e-waste) may release persistent organic pollutants and heavy metals that possess potential risk for human health. Lead (Pb) is carried through the circulatory system by erythrocytes and is known to alter the functions of hematopoietic and immune systems. The aim of the study was to investigate the effect of Pb exposure on blood morphology and erythrocyte complement receptor 1 (CR1) levels as related to immunologic function in preschool children. We recruited 484 preschool children, 2- to 6-years of age, among whom 332 children were from Guiyu, a typical and primitive e-waste processing area, and 152 children from Haojiang (reference area). Results showed that the blood Pb level (BPb) and erythrocyte Pb level (EPb) of exposed children were significantly higher, but, the mean corpuscular hemoglobin concentration (MCHC) and erythrocyte CR1 levels were significantly lower than reference children. Elevated EPb and BPb was related to disadvantageous changes in hematocrit (HCT), mean corpuscular volume (MCV), hemoglobin (HGB), mean corpuscular hemoglobin (MCH), and MCHC, respectively, in children from the e-waste recycling area. Furthermore, in the high Pb-exposed group, the Pb toxicity of erythrocytes was more significant compared to the low Pb-exposed group in e-waste-exposed children. Combine with the BPb and EPb would be better to evaluating the Pb toxicity of erythrocytes. Compared to low Pb exposure, high BPb and EPb were associated with lower erythrocyte CR1 expression in all children. Our data suggests that elevated Pb levels result in adverse changes in blood morphology, hemoglobin synthesis and CR1 expression, which might be a non-negligible threat to erythrocyte immunity development in local preschool children. It is therefore imperative for any intervention to control the Pb exposure of children and actively educate adults to raise their environmental awareness of potential e-waste pollution during the recycling process.

Monitoring seasonal influenza epidemics by using internet search data with an ensemble penalized regression model

Seasonal influenza epidemics cause serious public health problems in China. Search queries-based surveillance was recently proposed to complement traditional monitoring approaches of influenza epidemics. However, developing robust techniques of search query selection and enhancing predictability for influenza epidemics remains a challenge. This study aimed to develop a novel ensemble framework to improve penalized regression models for detecting influenza epidemics by using Baidu search engine query data from China. The ensemble framework applied a combination of bootstrap aggregating (bagging) and rank aggregation method to optimize penalized regression models. Different algorithms including lasso, ridge, elastic net and the algorithms in the proposed ensemble framework were compared by using Baidu search engine queries. Most of the selected search terms captured the peaks and troughs of the time series curves of influenza cases. The predictability of the conventional penalized regression models were improved by the proposed ensemble framework. The elastic net regression model outperformed the compared models, with the minimum prediction errors. We established a Baidu search engine queries-based surveillance model for monitoring influenza epidemics, and the proposed model provides a useful tool to support the public health response to influenza and other infectious diseases.

Pilot study on the internal exposure to heavy metals of informal-level electronic waste workers in Agbogbloshie, Accra, Ghana

Informal-level electronic waste (e-waste)-processing activities are performed at hotspots in developing countries such as India, China, and Ghana. These activities increase the ambient burden of heavy metals and contribute to the toxic exposure of the general population. However, few data exist on the internal exposure of populations involved in these informal activities and in close contact with fumes from the direct combustion of electronic waste products in these countries. Therefore, in a cross-sectional study design, we analyzed blood, urine, and hair samples from 75 e-waste workers residing in and/or working on a large e-waste recycling site in Agbogbloshie, Accra, Ghana, and compared the results against those of 40 individuals living in a suburb of Accra without direct exposure to e-waste recycling activities. A comparative analysis using the Mann-Whitney U test showed significantly higher median concentrations of blood lead (88.5 vs. 41.0 μg/l, p < 0.001), cadmium (0.12 vs. 0.10 μg/g_crea, p = 0.023), chromium (0.34 vs. 0.23 μg/g_crea, p < 0.001), and nickel (3.18 vs. 2.03 μg/g_crea, p < 0.001) in the urine of e-waste workers than those of controls. There was no difference in blood cadmium concentrations between the groups (0.51 vs. 0.57 μg/l, p = 0.215) or in urine mercury levels (0.18 vs. 0.18 μg/g_crea, p = 0.820). Hair mercury levels were higher in the controls than in the e-waste workers (0.43 vs. 0.72, p < 0.001). We compared our data with those from European populations, specifically using the German reference values, and found that the internal concentrations of the participants exceeded the German reference values in 59.3 vs. 3.1% (e-waste workers vs. controls) for blood lead, 56.9 vs. 52.5% for urine nickel, 22.2 vs. 20.0% for urine chromium, and 17.8 vs. 62.2% for hair mercury. In particular, the high blood lead levels of up to several hundred micrograms per liter are a cause for concern because many of the workers in Agbogbloshie are children or adolescents who are in developmental stages and are at a particular risk for negative health effects. We conclude that exposure to some of the heavy metals tended to be a citywide phenomenon, but populations directly exposed to e-waste recycling are experiencing higher exposure levels and have concentration levels much higher than those of the general population and much higher than those found in European populations. To achieve environmental sustainability and to minimize the impact of e-waste-processing activities in developing countries, national authorities must formalize the rapidly growing informal-level e-waste management sector in these countries by deploying cleaner and easy-to-operate e-waste processing technologies.

Considerable decrease of antibody titers against measles, mumps, and rubella in preschool children from an e-waste recycling area

Data on vaccination effects in children chronically exposed to heavy metals are extremely scarce. This study aims to investigate the immune responsiveness to measles, mumps, and rubella (MMR) vaccination in children from an e-waste recycling area. 378 healthy children from Guiyu (exposed group) and Haojiang (reference group) were surveyed. Blood lead (Pb) levels were measured by graphite furnace atomic absorption. Titers of antibodies against MMR were quantified by ELISA. Blood Pb levels of children from the exposed group were significantly higher than those from the reference group (5.61μg/dL vs. 3.57μg/dL, p<0.001). In contrast, the antibody titers against MMR of the children from the exposed group were significantly lower than those from the reference group. The median titer of the anti-measles antibody of the exposed group was 669.64mIU/mL, with an interquartile range of 372.88-1068.42mIU/mL; this was decreased by nearly 40% compared to that of the reference group (median 1046.79mIU/mL, interquartile range 603.29-1733.10mIU/mL). For antibody titers against mumps, there was an about 45% decrease in the exposed group (median 272.24U/mL, interquartile range 95.19-590.16U/mL), compared to the reference group (median 491.78U/mL, interquartile range 183.38-945.96U/mL). In the case of rubella, the median titer of the antibody was also significantly lower in the exposed group (median 37.08IU/mL, interquartile range 17.67-66.66IU/mL) compared to the reference group (median 66.50IU/mL, interquartile range 25.32-105.59IU/mL); the decrease in this case was nearly 44%. The proportion of children whose antibody titers against MMR were below protective level in the exposed group was higher than it was in the reference group. The present study demonstrates that the immune responsiveness to routine vaccination was suppressed in children chronically exposed to lead. Thus, the vaccination strategies for these children living in an e-waste recycling area should be modified.

Sleep duration, daytime napping, markers of obstructive sleep apnea and stroke in a population of southern China

Sleep habits are associated with stroke in western populations, but this relation has been rarely investigated in China. Moreover, the differences among stroke subtypes remain unclear. This study aimed to explore the associations of total stroke, including ischemic and hemorrhagic type, with sleep habits of a population in southern China. We performed a case-control study in patients admitted to the hospital with first stroke and community control subjects. A total of 333 patients (n = 223, 67.0%, with ischemic stroke; n = 110, 23.0%, with hemorrhagic stroke) and 547 controls were enrolled in the study. Participants completed a structured questionnaire to identify sleep habits and other stroke risk factors. Least absolute shrinkage and selection operator (Lasso) and multiple logistic regression were performed to identify risk factors of disease. Incidence of stroke, and its subtypes, was significantly associated with snorting/gasping, snoring, sleep duration, and daytime napping. Snorting/gasping was identified as an important risk factor in the Lasso logistic regression model (Lasso' β = 0.84), and the result was proven to be robust. This study showed the association between stroke and sleep habits in the southern Chinese population and might help in better detecting important sleep-related factors for stroke risk.

The Risk Factors of Child Lead Poisoning in China: A Meta-Analysis

BACKGROUND

To investigate the risk factors of child lead poisoning in China.

METHODS

A document retrieval was performed using MeSH (Medical subject heading terms) and key words. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the studies, and the pooled odd ratios with a 95% confidence interval were used to identify the risk factors. We employed Review Manager 5.2 and Stata 10.0 to analyze the data. Heterogeneity was assessed by both the Chi-square and I² tests, and publication bias was evaluated using a funnel plot and Egger's test.

RESULTS

Thirty-four articles reporting 13,587 lead-poisoned children met the inclusion criteria. Unhealthy lifestyle and behaviors, environmental pollution around the home and potential for parents' occupational exposure to lead were risk factors of child lead poisoning in the pooled analyses. Our assessments yielded no severe publication biases.

CONCLUSIONS

Seventeen risk factors are associated with child lead poisoning, which can be used to identify high-risk children. Health education and promotion campaigns should be designed in order to minimize or prevent child lead poisoning in China.

Heavy metals in PM2.5 and in blood, and children's respiratory symptoms and asthma from an e-waste recycling area

This study was to investigate the levels of heavy metals in PM2.5 and in blood, the prevalence of respiratory symptoms and asthma, and the related factors to them. Lead and cadmium in both PM2.5 and blood were significant higher in Guiyu (exposed area) than Haojiang (reference area) (p < 0.05), however, no significant difference was found for chromium and manganese in PM2.5 and in blood. The prevalence of cough, phlegm, dyspnea, and wheeze of children was higher in Guiyu compared to Haojiang (p < 0.05). No significant difference was found for the prevalence of asthma in children between Guiyu and Haojiang. Living in Guiyu was positively associated with blood lead (B = 0.196, p < 0.001), blood cadmium (B = 0.148, p < 0.05) and cough (OR, 2.37; 95% CI, 1.30-4.32; p < 0.01). Blood lead>5 μg/dL was significantly associated with asthma (OR, 9.50; 95% CI, 1.16-77.49). Higher blood chromium and blood manganese were associated with more cough and wheeze, respectively. Our data suggest that living in e-waste exposed area may lead to increased levels of heavy metals, and accelerated prevalence of respiratory symptoms and asthma.

Decreased blood hepatitis B surface antibody levels linked to e-waste lead exposure in preschool children

Lead (Pb) is a widespread environmental contaminant that can profoundly affect the immune system in vaccinated children. To explore the association between blood Pb and HBsAb levels in children chronically exposed to Pb, we measured hepatitis B surface antibody (HBsAb) titers, to reflect the immune response in the children of Guiyu, an electronic and electrical waste (e-waste) recycling area well known for environmental Pb contamination. We performed secondary exploratory analyses of blood Pb levels and plasma HBsAb titers in samples, taken in two phases between 2011 and 2012, from 590 children from Guiyu (exposed group) and Haojiang (reference group). Children living in the exposed area had higher blood Pb levels and lower HBsAb titers compared with children from the reference area. At each phase, generalized linear mixed models (GLMMs) showed that HBsAb titers were significantly negatively associated with child blood Pb levels. This work shows that a decreased immune response to hepatitis B vaccine and immune system might have potential harm to children with chronic Pb exposure. Importantly, nearly 50% of chronically exposed children failed to develop sufficient immunity to hepatitis in response to vaccination. Thus different vaccination strategies are needed for children living under conditions of chronic Pb exposure.

Improved Variable Selection Algorithm Using a LASSO-Type Penalty, with an Application to Assessing Hepatitis B Infection Relevant Factors in Community Residents

OBJECTIVES

In epidemiological studies, it is important to identify independent associations between collective exposures and a health outcome. The current stepwise selection technique ignores stochastic errors and suffers from a lack of stability. The alternative LASSO-penalized regression model can be applied to detect significant predictors from a pool of candidate variables. However, this technique is prone to false positives and tends to create excessive biases. It remains challenging to develop robust variable selection methods and enhance predictability.

MATERIAL AND METHODS

Two improved algorithms denoted the two-stage hybrid and bootstrap ranking procedures, both using a LASSO-type penalty, were developed for epidemiological association analysis. The performance of the proposed procedures and other methods including conventional LASSO, Bolasso, stepwise and stability selection models were evaluated using intensive simulation. In addition, methods were compared by using an empirical analysis based on large-scale survey data of hepatitis B infection-relevant factors among Guangdong residents.

RESULTS

The proposed procedures produced comparable or less biased selection results when compared to conventional variable selection models. In total, the two newly proposed procedures were stable with respect to various scenarios of simulation, demonstrating a higher power and a lower false positive rate during variable selection than the compared methods. In empirical analysis, the proposed procedures yielding a sparse set of hepatitis B infection-relevant factors gave the best predictive performance and showed that the procedures were able to select a more stringent set of factors. The individual history of hepatitis B vaccination, family and individual history of hepatitis B infection were associated with hepatitis B infection in the studied residents according to the proposed procedures.

CONCLUSIONS

The newly proposed procedures improve the identification of significant variables and enable us to derive a new insight into epidemiological association analysis.

Associations of cadmium, bisphenol A and polychlorinated biphenyl co-exposure in utero with placental gene expression and neonatal outcomes

In utero co-exposure to endocrine disrupting compounds can perturb fetal development. However, the effect of co-exposure on pivotal regulatory genes has seldom been investigated. We explored the effects of in utero co-exposure to cadmium (Cd), bisphenol A (BPA) and polychlorinated biphenyls (PCBs) on master regulator genes. We recruited 284 healthy pregnant women, of whom 262 provided both cord blood and placenta samples, and 200 had all measurements taken. Placental Cd, cord blood BPA and total PCBs in the exposed group were higher than a reference group. KISS1 expression level in placental tissue was threefold higher in the exposed group than in the reference, and was positively associated with all toxicants. Leptin and leptin receptor expression were also significantly higher, but were only associated with BPA. From our findings, we conclude that lower birth weight is correlated with Cd and PCBs, and may result from the increased KISS1 mRNA expression.