Gender differences in trace element exposures with cognitive abilities of school-aged children: a cohort study in Wujiang city, China

Effects of Blood Lead Levels <10 µg/dL in School-Age Children and Adolescents: A Scoping Review

CONTEXT

Lead exposures among school-age children are a major public health issue. Although the harmful effects of lead exposure during the first years of life are well known, there is not as much understanding of the effects of low levels of lead exposure during later childhood.

OBJECTIVES

To review the effects of blood lead levels (BLLs) <10 µg/dL in school-age children and adolescents.

DATA SOURCES

We searched Medline, Embase, Global health, CINAHL, Scopus, and Environmental Science Collection databases between January 1, 2000, and May 11, 2023.

STUDY SELECTION

We included peer-reviewed English-language articles that presented data on the effects of BLLs <10 µg/dL in individuals ages 5 through 18 years.

DATA EXTRACTION

Data on country, population, analytic design, sample size, age, BLLs, outcomes, covariates, and results were extracted.

RESULTS

Overall, 115 of 3180 screened articles met the inclusion criteria. The reported mean or median BLL was <5 µg/dL in 98 articles (85%). Of the included articles, 89 (77%) presented some evidence of an association between BLLs <10 µg/dL during school age and detrimental outcomes in a wide range of categories. The strongest evidence of an association was for the outcomes of intelligence quotient and attention-deficit/hyperactivity disorder diagnoses or behaviors.

LIMITATIONS

Few articles controlled for BLLs at age <5 years, limiting conclusions about the relation between later BLLs and outcomes.

CONCLUSIONS

BLLs <10 µg/dL in school-age children and adolescents may be associated with negative outcomes. This review highlights areas that could benefit from additional investigation.

High ambient temperature may increase the risk of anemia in pregnancy: Identifying susceptible exposure windows

Anemia in pregnancy (AIP) is associated with multiple severe maternal and perinatal adverse outcomes. However, there is a lack of evidence on the association between environmental factors and AIP. Aim to explore the association between ambient temperature and the risk of AIP, and identify susceptible exposure windows, we conducted a matched case-control study from 2013 to 2016 in Xi'an, China, which included 710 women with AIP and 1420 women without AIP. The conditional logistic regression model was used to evaluate the association between ambient temperature and AIP at different gestational weeks and gestational months. The association between extreme temperature and AIP was evaluated using the distributed lag nonlinear model (DLNM). We conducted stratified analyses of age, parity, and season of conception, and estimated the interaction between ambient temperature and air pollutants on AIP. Ambient temperature was significantly positively associated with the risk of AIP, and the susceptible exposure windows were 2-25 gestational weeks and 1-6 gestational months, respectively. The strongest effect was observed in the week 8 and month 2, for each 1 °C increase in weekly and monthly mean temperature, the odds ratio (OR) for AIP was 1.038 (95 % confidence interval (CI): 1.022, 1.055) and 1.040 (95 % CI: 1.020, 1.060), respectively. Extreme heat may increase the risk of AIP. Stratified analyses showed that there was no significant difference among different age, parity, and season of conception groups. No significant interaction effect of ambient temperature with air pollution on AIP was found. In summary, high ambient temperature may increase the risk of AIP, and the first and second trimesters may be susceptible exposure windows. Understanding the effect of temperature on pregnant women will be beneficial to reduce the occurrence of AIP.

Update of the risk assessment of inorganic arsenic in food

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 μg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

Evaluation of School-Age Children's Intelligence Quotient and Their Chronic Exposure to Trace Elements in Ambient Air

Background Children's exposure to different trace elements in their air, water, and food or even present in paints or toys can affect their intelligence quotient (IQ) score. However, this correlation needs to be analyzed and evaluated in different contexts. This study aimed to investigate the associations between airborne concentrations of lead (Pb), manganese (Mn), cadmium (Cd), chromium (Cr), and arsenic (As) and intellectual function in school-age children in Makkah, Kingdom of Saudi Arabia. Methodology Our cohort study aimed to explore the link between exposure to various trace elements in the surrounding air and the IQ scores of children residing in the vicinity of Makkah. We included 430 children in the study and collected information about demographic and lifestyle factors using a structured questionnaire. We employed a mini volume sampler (MiniVol, AirMetrics, Springfield, OR, USA) to collect 24-hour PM10 samples from five locations in Makkah, representing various residential areas with small-to-medium industrial activities and traffic load. We analyzed the samples for Pb, Mn, Cd, Cr, and As concentrations using inductively coupled plasma-mass spectrometry with Perkin Elmer 7300 (Perkin Elmer, Waltham, MA, USA). The combined impact of heavy metals on continuous outcomes was assessed using the Bayesian kernel machine regression model. Results The mean atmospheric concentrations of Pb, Mn, Cd, Cr, and As in summer were 0.093, 0.006, 0.36, 0.15, and 0.017 µg/m³, respectively, while in winter, they were 0.004, 0.003, 0.12, 0.006, and 0.01 µg/m³, respectively. The findings of our study revealed that children's IQ scores were independently associated with co-exposure to the five metals, namely, Pb, Mn, Cd, Cr, and As. Conclusions This study demonstrates a link between combined exposure to five heavy metals (Pb, Mn, Cd, Cr, and As) and children's IQ scores. Regularly evaluating trace elements in children's biological samples is crucial to comprehend their effects on cognitive growth. To explore the possible future health risks of multimetal exposures and their interaction effects, it is imperative to conduct additional studies that involve repeated biological measurements of metal concentrations.

Selenium Status in Paediatric Patients with Neurodevelopmental Diseases

Neurodevelopmental diseases are often associated with other comorbidities, especially inflammatory processes. The disease may affect the trace element (TE) status, which in turn may affect disease severity and progression. Selenium (Se) is an essential TE required for the biosynthesis of selenoproteins including the transporter selenoprotein P (SELENOP) and extracellular glutathione peroxidase (GPX3). SELENOP deficiency in transgenic mice resulted in a Se status-dependent phenotype characterized by impaired growth and disturbed neuronal development, with epileptic seizures on a Se-deficient diet. Therefore, we hypothesized that Se and SELENOP deficiencies may be prevalent in paediatric patients with a neurodevelopmental disease. In an exploratory cross-sectional study, serum samples from children with neurodevelopmental diseases (n = 147) were analysed for total serum Se, copper (Cu), and zinc (Zn) concentrations as well as for the TE biomarkers SELENOP, ceruloplasmin (CP), and GPX3 activity. Children with epilepsy displayed elevated Cu and Zn concentrations but no dysregulation of serum Se status. Significantly reduced SELENOP concentrations were found in association with intellectual disability (mean ± SD (standard deviation); 3.9 ± 0.9 mg/L vs. 4.4 ± 1.2 mg/L, p = 0.015). A particularly low GPX3 activity (mean ± SD; 172.4 ± 36.5 vs. 192.6 ± 46.8 U/L, p = 0.012) was observed in phacomatoses. Autoantibodies to SELENOP, known to impair Se transport, were not detected in any of the children. In conclusion, there was no general association between Se deficiency and epilepsy in this observational analysis, which does not exclude its relevance to individual cases. Sufficiently high SELENOP concentrations seem to be of relevance to the support of normal mental development. Decreased GPX3 activity in phacomatoses may be relevant to the characteristic skin lesions and merits further analysis. Longitudinal studies are needed to determine whether the observed differences are relevant to disease progression and whether correcting a diagnosed TE deficiency may confer health benefits to affected children.