Early Blood Lead Levels and Sleep Disturbance in Preadolescence

The Causal Association Between Blood Lead and Sleep Disorders: Evidence from National Health and Nutrition Examination Survey and Mendelian Randomization Analysis

BACKGROUND

Poor sleep quality is a global public health concern. This study aimed to identify the risk factors for sleep disorders and clarify their causal effects.

METHODS

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) and Mendelian randomization (MR)-Base databases. Baseline characteristics of individuals with and without sleep disorders were compared. A multivariate logistic regression analysis was performed to calculate the effects of each variable on sleep disorders. Causal effects of blood lead levels and hypertension on sleep disorders were assessed using MR analysis.

RESULTS

In total, 3660 individuals were enrolled in the study. The prevalence of self-reported sleep disorders was 26.21%. Serum lead level, serum mercury level, serum retinol level, prevalence of hypertension, and daily vigorous work duration were significantly higher for those in the sleep disorders group than the control group. After adjusting for various covariates, the effects of serum lead and hypertension on sleep disorders were stable from logistic regression models 1-4. MR analysis showed that blood lead levels were causally related to the risk of sleep disorders (odds ratio (OR) = 1.09, 95% confidence interval (CI) 1.01-1.17, P = 0.030). There was no causal link between elevated blood pressure and sleep disorders (OR = 0.99, 95% CI 0.94-1.04, P = 0.757). Goodness-of-fit tests and sensitivity analyses were used to verify the reliability of the results.

CONCLUSIONS

Blood lead is positively and causally associated with an increased risk of sleep disorders. These findings provide a novel perspective regarding sleep protection. Taking effective measures to reduce lead exposure may significantly improve sleep health.

Effects of Cadmium and Lead Co-exposure on Sleep Status in Rural Areas Northwestern China

In this study, we explored how cadmium and lead co-exposure affects sleep status among residents of a polluted area and nature reserve in rural northwestern China. Cadmium and lead levels were measured using blood samples, and sleep status was evaluated using sleep questionnaires, with the main sleep indicators including sleep duration, sleep quality, bedtime, and staying up. Furthermore, cadmium-lead co-exposure levels were divided into three groups: high exposure, medium exposure, and low exposure. Subjects in the contaminated area had significantly higher exposure levels (p < 0.001) and more negative sleep indicators (p < 0.01). Significant differences were found for all four sleep indicators in the high exposure group compared to the low exposure group (p < 0.01). Moreover, the overall evaluation of sleep status with high cadmium-lead co-exposure had a negative impact. Our data suggest that cadmium-lead co-exposure has a negative effect on sleep status and may have a synergistic effect on sleep.

Assessing Neurobehavioral Alterations Among E-waste Recycling Workers in Hong Kong

Background

E-waste workers in Hong Kong are handling an unprecedented amount of e-waste, which contains various neurotoxic chemicals. However, no study has been conducted to evaluate the neurological health status of e-waste workers in Hong Kong. This study aimed to evaluate the prevalence of neurobehavioral alterations and to identify the vulnerable groups among Hong Kong e-waste workers.

Methods

We recruited 109 Hong Kong e-waste workers from June 2021 to September 2022. Participants completed standard questionnaires and wore a GENEActiv accelerometer for seven days. Pittsburgh Sleep Quality Index and Questionnaire 16/18 (Q16/18) were used to assess subjective neurobehavioral alterations. The GENEActiv data generated objective sleep and circadian rhythm variables. Workers were grouped based on job designation and entity type according to the presumed hazardous level. Unconditional logistic regression models measured the associations of occupational characteristics with neurobehavioral alterations after adjusting for confounders.

Results

While dismantlers/repairers and the workers in entities not funded by the government were more likely to suffer from neurotoxic symptoms in Q18 (adjusted odds ratio: 3.18 [1.18-9.39] and 2.77 [1.10-7.46], respectively), the workers from self-sustained recycling facilities also have poor performances in circadian rhythm. Results also showed that the dismantlers/repairers working in entities not funded by the government had the highest risk of neurotoxic symptoms compared to the lowest-risk group (i.e., workers in government-funded companies with other job designations).

Conclusion

This timely and valuable study emphasizes the importance of improving the working conditions for high-risk e-waste workers, especially the dismantlers or repairers working in facilities not funded by the government.

Childhood sleep: assessments, risk factors, and potential mechanisms

BACKGROUND

Sleep problem is a highly prevalent health issue among pediatric populations across the world. In this review, we aimed to identify risk factors contributing to sleep deficiency and poor sleep hygiene in children. Potential biological, psychosocial, and environmental mechanisms as well as research gaps in the literature are also discussed.

DATA SOURCES

A comprehensive search for relevant English language full-text, peer-reviewed publications was performed focusing on pediatric sleep studies from prenatal to childhood and adolescence in a variety of indexes in PubMed, SCOPUS, and Psych Info. Both relevant data based and systematic reviews are included.

RESULTS

This paper summarizes many risk factors for childhood sleep problems, including biological (e.g., genetics, gender, age and puberty, prenatal factors, postnatal factors); nutritional (e.g., macronutrients, micronutrients, omega-3 fatty acids, obesity); environmental (e.g., heavy metals, noise, light, air pollution); interpersonal (e.g., family, exposure to violence, screen media use, physical injury); and community/socioeconomic variables (e.g., racial/ethnicity and cultural factors, neighborhood conditions and socioeconomic status, school factors, public health disasters/emergencies), to better understand the development of sleep problems in children.

CONCLUSIONS

Poor childhood sleep is a multifactorial issue affected by a wide range of prenatal and early-life biological, environmental, and psychosocial risk factors and contributors. A better understanding of these risk factors and their mechanisms is an important first step to develop future research and prevention programs focusing on pediatric sleep problems.

Family- and neighborhood-level environmental associations with physical health conditions in 9- and 10-year-olds

OBJECTIVE

To determine how environmental factors are associated with physical health conditions in 9- to 10-year-old participants in the Adolescent Brain Cognitive Development (ABCD) Study, and how they are moderated by family-level socioeconomic status (SES).

METHOD

We performed cross-sectional analyses of 8,429 youth participants in the ABCD Study, in which nine physical health conditions (having underweight or overweight/obesity, not participating in sports activities, short sleep duration, high sleep disturbances, lack of vigorous and strengthening-related physical activity, miscellaneous medical problems, and traumatic brain injury) were regressed on three environmental factors [neighborhood disadvantage (area deprivation index [ADI]), risk of lead exposure, and concentrations of particulate matter 2.5 (PM2.5)] and their interaction with family-level SES (i.e., parent-reported annual household income). Environmental data were geocoded to participants' primary residential addresses at 9- to 10-year-olds.

RESULTS

Risk of lead exposure and ADI were positively associated with the odds of having overweight/obesity, not participating in sports activity, and short sleep durations. ADI was also positively associated with high sleep disturbances. PM2.5 was positively associated with the odds of having overweight/obesity and reduced vigorous physical activity. Family-level SES moderated relationships between ADI and both underweight and overweight/obesity, with high SES being associated with more pronounced changes given increased ADI.

CONCLUSIONS

Policymakers and public health officials must implement policies and remediation strategies to ensure children are free from exposure to neurotoxicant and environmental factors. Physical health conditions may be less of a product of an individual's choices and more related to environmental influences. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Is exposure to chemical pollutants associated with sleep outcomes? A systematic review

Environmental exposures may influence sleep; however, the contributions of environmental chemical pollutants to sleep health have not been systematically investigated. We conducted a systematic review to identify, evaluate, summarize, and synthesize the existing evidence between chemical pollutants (air pollution, exposures related to the Gulf War and other conflicts, endocrine disruptors, metals, pesticides, solvents) and dimensions of sleep health (architecture, duration, quality, timing) and disorders (sleeping pill use, insomnia, sleep-disordered breathing)). Of the 204 included studies, results were mixed; however, the synthesized evidence suggested associations between particulate matter, exposures related to the Gulf War, dioxin and dioxin-like compounds, and pesticide exposure with worse sleep quality; exposures related to the Gulf War, aluminum, and mercury with insomnia and impaired sleep maintenance; and associations between tobacco smoke exposure with insomnia and sleep-disordered breathing, particularly in pediatric populations. Possible mechanisms relate to cholinergic signaling, neurotransmission, and inflammation. Chemical pollutants are likely key determinants of sleep health and disorders. Future studies should aim to evaluate environmental exposures on sleep across the lifespan, with a particular focus on developmental windows and biological mechanisms, as well as in historically marginalized or excluded populations.

Interactions between heavy metals and sleep duration among pre-and postmenopausal women: A current approach to molecular mechanisms involved

The effects of heavy metals (cadmium, lead, and mercury) and their mixtures on sleep duration in pre-and postmenopausal women, particularly the molecular mechanisms, remain unknown. Here, we assessed the interaction between heavy metals and sleep duration among pre-and postmenopausal women (n = 1134). Furthermore, molecular mechanisms related to sleep disorders induced by studied heavy metals were further analyzed to support the previous findings. We found that serum lead levels were positively related to weekend and weekday sleep duration in premenopausal women. There were interactions between serum lead and mercury and menopausal status for sleep duration. Serum lead and mercury levels were shown to be inversely related to sleep duration in postmenopausal women. Despite the lack of statistically significant associations between mixed heavy metals and sleep duration, there were increasing trends in premenopausal women's sleeping patterns and decreasing trends in postmenopausal women's sleeping patterns. In silico analysis, IL1B, hsa-21-5p, hsa-887-3p, hsa-877-3p, and NR4A1 were identified as the most relevant genes, miRNAs, and transcription factors linked with sleep disorders induced by combined heavy metals (cadmium, lead, and mercury). Furthermore, "type 1 melanocortin receptor binding," "endocrine hormone secretion," "interleukin-1 receptor antagonist activity," "altered melanocortin system," and "sleep wake disorders" were identified as the predominant molecular mechanisms involved in the pathophysiology of sleep disorders induced by the studied heavy metals. Cut off point values and miRNA sponge templates for heavy metal exposure levels relevant to sleep disorders in pre- and postmenopausal women were reported. Future research is needed to verify our findings and provide insight into the molecular processes of long-term mixed heavy metal exposure in various populations, such as children and the elderly.

Longitudinal association of early childhood lead exposure and adolescent heart rate variability: influence of parental education

Lead exposure has been shown to dysregulate physiological stress responses. However, few studies have investigated the effect of lead exposure on later heart rate variability (HRV), an indicator of a stress response, in large samples of children. Furthermore, the interaction between social environmental factors and lead exposure in childhood, which commonly co-occur, remains understudied. This study examined relationships between childhood lead exposure and early adolescent physiological stress responses at different levels of parental education. Participants were 406 children from Jintan, China. Blood lead levels (BLLs) and parental education data were collected at 3-5 years of age, and HRV outcomes assessed at 12 years via frequency domain measures (LF/HF ratio) collected during an induced stress test. Results show a significant interaction between parental education and BLLs at 3-5 years. This relationship was found to be most consistent for the interaction between BLLs and mother's years of education for both the planning (β = 0.12, p = 0.046) and speaking (β = 0.11, p = 0.043) phase of the stress task, suggesting that increasing years of mother's education may enhance the deleterious influence of lead exposure on the HRV frequency measure, LF/HF ratio. This research highlights the complexity in lead exposure induced outcomes.

Disrupted Sleep Homeostasis and Altered Expressions of Clock Genes in Rats with Chronic Lead Exposure

Sleep disturbance is one of the neurobehavioral complications of lead neurotoxicity. The present study evaluated the impacts of chronic lead exposure on alteration of the sleep–wake cycle in association with changes of clock gene expression in the hypothalamus. Sprague–Dawley rats with chronic lead exposure consumed drinking water that contained 250 ppm of lead acetate for five weeks. Electroencephalography and electromyography were recorded for scoring the architecture of the sleep–wake cycle in animals. At six Zeitgeber time (ZT) points (ZT2, ZT6, ZT10, ZT14, ZT18, and ZT22), three clock genes, including rPer1, rPer2, and rBmal1b, were analyzed. The rats with chronic lead exposure showed decreased slow wave sleep and increased wakefulness in the whole light period (ZT1 to ZT12) and the early dark period (ZT13 to ZT15) that was followed with a rebound of rapid-eye-movement sleep at the end of the dark period (ZT22 to ZT24). The disturbance of the sleep–wake cycle was associated with changes in clock gene expression that was characterized by the upregulation of rPer1 and rPer2 and the feedback repression of rBmal1b. We concluded that chronic lead exposure has a negative impact on the sleep–wake cycle in rats that predominantly disrupts sleep homeostasis. The disruption of sleep homeostasis was associated with a toxic effect of lead on the clock gene expression in the hypothalamus.

Chronic lead exposure alters photic entrainment of locomotor activity rhythm and neuronal photoactivation in the suprachiasmatic nucleus of the adult rat

Chronic lead (Pb) exposure affects the circadian physiological processes regulated by suprachiasmatic nucleus (SCN), which is synchronized (entrainment) by light. Disorders in the entrainment capacity of an organism alter its performance to interact with the environment, thus affecting its health status. The objectives of the present study were to evaluate whether chronic early Pb exposure affects the entrainment of the circadian rhythm of locomotor activity by light and to explore the possible mechanisms involved. Adult male Wistar rats, control and chronically exposed to Pb (320 ppm) in drinking water from gestation to adult age, were used. Assessment of the metal level showed a significant increase of Pb in the blood, hypothalamus and prefrontal cortex of the experimental rats. Continuous registrations of locomotor activity (12 h:12 h light-dark cycle) depicted that Pb induces important delay of this activity when the light was turned off. The Pb exposed animals entrained faster with a photoperiod delay of 6 h, (lights on at 13:00 h), and maintained the significant delay in the onset of activity at lights out. In continuous darkness, the animals were exposed to a light pulse at circadian time 23. This resulted in a significant decrease of photo-stimulated neurons (immunoreactivity to c-Fos) in the SCN of the metal-exposed animals. These results show that chronic early Pb exposure alters the photic entrainment of the rhythm of locomotor activity, which is evidenced by a significant decrease in both the number of photo-stimulated neurons and neuronal population (Nissl stain) of the SCN.

Environmental exposures and sleep outcomes: A review of evidence, potential mechanisms, and implications

Environmental exposures and poor sleep outcomes are known to have consequential effects on human health. This integrative review first seeks to present and synthesize existing literature investigating the relationship between exposure to various environmental factors and sleep health. We then present potential mechanisms of action as well as implications for policy and future research for each environmental exposure. Broadly, although studies are still emerging, empirical evidence has begun to show a positive association between adverse effects of heavy metal, noise pollution, light pollution, second-hand smoke, and air pollution exposures and various sleep problems. Specifically, these negative sleep outcomes range from subjective sleep manifestations, such as general sleep quality, sleep duration, daytime dysfunction, and daytime sleepiness, as well as objective sleep measures, including difficulties with sleep onset and maintenance, sleep stage or circadian rhythm interference, sleep arousal, REM activity, and sleep disordered breathing. However, the association between light exposure and sleep is less clear. Potential toxicological mechanisms are thought to include the direct effect of various environmental toxicants on the nervous, respiratory, and cardiovascular systems, oxidative stress, and inflammation. Nevertheless, future research is required to tease out the exact pathways of action to explain the associations between each environmental factor and sleep, to inform possible therapies to negate the detrimental effects, and to increase efforts in decreasing exposure to these harmful environmental factors to improve health.

Blood lead and mercury levels are associated with low resting heart rate in community adolescent boys

While the neurotoxic effects of heavy metals at even low levels have been well-studied, few studies have examined the cardiovascular effects of heavy metals on resting heart rate and these have focused on adult populations. The present study aimed to examine the association between low-level environmental lead and mercury exposure and resting heart rate in community adolescents. As part of the China Jintan Cohort Study, 532 adolescents aged 12 years (SD = 0.6) were tested for blood levels of lead (BLL) and mercury (BML) and resting heart rate (RHR). Generalized linear models were conducted to test the relationship between BLL and BML and RHR, controlling for children's sex, age, and socioeconomic status. Analyses were clustered at the preschool level when the children were recruited to adjust for standard error. The mean (SD) BLL and BML were 3.14 (SD = 1.19) μg/dL and 1.26 (SD = 0.68) μg/L at age 12 years, respectively. After adjusting for confounders, we found a significant interaction between BML and BLL in predicting RHR in boys (B = -1.27, SE = 0.49, p < 0.01, n = 289). We created BLL and BML groups in boys based on median cut-offs. Boys in the High BLL/High BML group had significantly lower RHR (mean = 84.22 beats per minute [bpm], SD = 8.77, n = 61) than boys in the Low BLL/Low BML group (mean = 89.03 bpm, SD = 10.75, n = 69; p < 0.05). BML and BLL did not interact to predict RHR in girls (B = -0.18, SE = 0.88, p > 0.05, n = 242). Combined high BLL and BML were associated with low RHR in community adolescent boys. Low RHR is an indication of chronic under-arousal and has been implicated in psychopathology, particularly for externalizing behavior. Our findings may stimulate further communication and research in this area.

Developmental exposure to Pb2+ induces transgenerational changes to zebrafish brain transcriptome

Lead (Pb2+) is a major public health hazard for urban children, with profound and well-characterized developmental and behavioral implications across the lifespan. The ability of early Pb2+ exposure to induce epigenetic changes is well-established, suggesting that Pb2+-induced neurobehavioral deficits may be heritable across generations. Understanding the long-term and multigenerational repercussions of lead exposure is crucial for clarifying both the genotypic alterations behind these behavioral outcomes and the potential mechanism of heritability. To study this, zebrafish (Danio rerio) embryos (<2 h post fertilization; EK strain) were exposed for 24 h to waterborne Pb2+ at a concentration of 10 μM. This exposed F0 generation was raised to adulthood and spawned to produce the F1 generation, which was subsequently spawned to produce the F2 generation. Previous avoidance conditioning studies determined that a 10 μM Pb2+ dose resulted in learning impairments persisting through the F2 generation. RNA was extracted from control- and 10 μM Pb2+-lineage F2 brains, (n = 10 for each group), sequenced, and transcript expression was quantified utilizing Quant-Seq. 648 genes were differentially expressed in the brains of F2 lead-lineage fish versus F2 control-lineage fish. Pathway analysis revealed altered genes in processes including synaptic function and plasticity, neurogenesis, endocrine homeostasis, and epigenetic modification, all of which are implicated in lead-induced neurobehavioral deficits and/or their inheritance. These data will inform future investigations to elucidate the mechanism of adult-onset and transgenerational health effects of developmental lead exposure.

Blood lead levels in children in urban and rural areas: Using multilevel modeling to investigate impacts of gender, race, poverty, and the environment

Many studies of children's exposure to lead (Pb) are carried out in urban and industrialized environments. This study analyzed blood lead level (BLL) data collected from 2011 to 2016 from approximately 140,000 children ages <1 to 6 years across South Carolina (SC), including urban and rural areas. Individual-level characteristics included children's age, and race/ethnicity. Block group variables examined included population by race and ethnicity, households below the poverty level, median year homes built, urban/rural classification, and percent road coverage. BLL were higher in urban compared to rural children but increased to a greater extent in rural children from age < 1 year to 2 years. Road coverage was strongly associated with higher BLL in urban areas, and with home age more weakly, but neither road coverage nor home age was associated with BLL in rural areas. Young urban children may receive greater exposure to Pb from house dust and outdoor legacy Pb contamination, and young rural children through diet and drinking water. Black children had higher BLL in urban areas than white children, and the converse was true in rural areas. Population data indicated that rural areas had more poverty than urban areas, but strong associations between increased children's BLL and either ethnicity or socio-economic status (SES) at the block group level was not observed, likely due to distinct characteristics of poverty and geographic distribution by ethnicity in urban as compared to rural areas of SC. Individual demographics and environmental characteristics may be more closely associated with BLL than geographically aggregated SES and race/ethnicity characteristics. Interventions to reduce children's exposure to Pb should occur at as early an age as possible, and differences between rural and urban areas should be considered as interventions are developed to reduce children's BLL.

Prediction of sleep side effects following methylphenidate treatment in ADHD youth

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Sleep problems after stimulant use in ADHD were predicted using machine learning.

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Step-wise combination of multi-level features enhanced prediction performance.

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Fronto-striatal connectivity and DAT1, ADRA2A, SLC6A2 SNPs were key features.

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An accuracy of 95.5% was achieved by Logistic Ridge Regression in the training data.

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An accuracy of 86.1% was achieved by J48 in the independent validation analysis.

Objective

Sleep problems is the most common side effect of methylphenidate (MPH) treatment in ADHD youth and carry potential to negatively impact long-term self-regulatory functioning. This study aimed to examine whether applying machine learning approaches to pre-treatment demographic, clinical questionnaire, environmental, neuropsychological, genetic, and neuroimaging features can predict sleep side effects following MPH administration.

Method

The present study included 83 ADHD subjects as a training dataset. The participants were enrolled in an 8-week, open-label trial of MPH. The Barkley Stimulant Side Effects Rating Scale was used to determine the presence/absence of sleep problems at the 2nd week of treatment. Prediction of sleep side effects were performed with step-wise addition of variables measured at baseline: demographics (age, gender, IQ, height/weight) and clinical variables (ADHD Rating Scale-IV (ADHD-RS) and Disruptive Behavior Disorder rating scale) at stage 1, neuropsychological test (continuous performance test (CPT), Stroop color word test) and genetic/environmental variables (dopamine and norepinephrine receptor gene (DAT1, DRD4, ADRA2A, and SLC6A2) polymorphisms, blood lead, and urine cotinine level) at stage 2, and structural connectivities of frontostriatal circuits at stage 3. Three different machine learning algorithms ((Logistic Ridge Regression (LR), support vector machine (SVM), J48) were used for data analysis. Robustness of classifier model was validated in the independent dataset of 36 ADHD subjects.

Results

Classification accuracy of LR was 95.5% (area under receiver operating characteristic curve (AUC) 0.99), followed by SVM (91.0%, AUC 0.85) and J48 (90.0%, AUC 0.87) at stage 3 for predicting sleep problems. The inattention symptoms of ADHD-RS, CPT response time variability, the DAT1, ADRA2A DraI, and SLC6A2 A-3081T polymorphisms, and the structural connectivities between frontal and striatal brain regions were identified as the most differentiating subset of features. Validation analysis achieved accuracy of 86.1% (AUC 0.92) at stage 3 with J48.

Conclusions

Our results provide preliminary support to the combination of multimodal classifier, in particular, neuroimaging features, as an informative method that can assist in predicting MPH side effects in ADHD.

Cumulative Childhood Lead Levels in Relation to Sleep During Adolescence

STUDY OBJECTIVES

Lead exposure has been linked to adverse cognitive outcomes among children, and sleep disturbances could potentially mediate these relationships. As a first step, whether childhood lead levels are linked to sleep disturbances must be ascertained. Prior studies of lead and sleep are scarce and rely on parent-reported sleep data.

METHODS

The study population included 395 participants from the Early Life Exposure in Mexico to Environmental Toxicants project, a group of sequentially enrolled birth cohorts from Mexico City. Blood lead levels measured from ages 1 to 4 years were used to calculate a cumulative measure of early childhood lead levels. Average sleep duration, sleep fragmentation, and movement index were assessed once between the ages of 9 and 18 years with wrist actigraphs worn for a continuous 7-day interval. Linear regression models were fit with average sleep duration, fragmentation, or movement as the outcome and cumulative lead levels divided into quartiles as the exposure, adjusted for age, sex, and maternal education.

RESULTS

Mean (standard deviation) age at follow-up was 13.8 (1.9) years, and 48% of participants were boys. Median (interquartile range) cumulative childhood lead level was 13.7 (10.8, 18.0) μg/dL. Patients in the highest quartile of the cumulative childhood lead group had on average 23 minutes less sleep than those in the first quartile in adolescence (95% confidence interval [7, 39]; P, trend = .02). Higher cumulative lead level was associated with higher sleep fragmentation in younger adolescents (younger than 14 years) only (P, interaction = .02).

CONCLUSIONS

Shorter sleep duration may represent an as-yet unrecognized adverse consequence of lead exposure in youth.

Childhood lead poisoning from domestic products in China: A case study with implications for practice, education, and policy

OBJECTIVE

This study aimed to report three representative childhood lead poisoning cases in China from domestic products exposure and to highlight their critical implications for practice, education, and policy in prevention and treatment of childhood lead poisoning by health care providers, especially public health nurses.

DESIGN AND SAMPLE

Three representative childhood lead poisoning cases occurring in 2017 were collected and analyzed.

RESULTS

The lead exposure sources of three cases were evaluated by experts in the field and determined to be tin pots, home factories for tinfoil, and contamination of folk medicine, respectively. These cases demonstrated that the lack of lead exposure risk assessment, insufficient knowledge of potential lead exposure sources, underdeveloped policy, and regulations were areas for improvement.

CONCLUSIONS

The best strategies for preventing lead poisoning include an appropriate risk assessment of lead exposure, implementation of comprehensive parental health education, conduction of further research by public health providers, and the application of policy strategies by the government. It was determined that public health nurses are at the frontline of prevention of lead poisoning in children.

Agreement between parent-reports and child self-reports of sleep problems in Chinese children

Sleep problems are major concerns for parents, health professionals, and children and youths themselves. For assessing sleep problems, both parent and child reports are important, with each having its unique features. However, little is known about the correlates of the agreement between parent and child self-reports. This study evaluated the agreement between the youth self-report sleep questionnaire (YSRSQ) and the parent-reported children's sleep habits questionnaire (CSHQ) and assessed the associated sociodemographic factors, as well as the underlying discrepancies. The participants included 3143 pairs of Chinese preadolescents (mean age = 11.03, SD = 0.98) and parents. Sleep-disordered breathing (SDB), daytime sleepiness, and parasomnia were assessed by both the YSRSQ and CSHQ. Significant but low correlations were present between parent report and preadolescent self-report items on SDB problems, daytime sleepiness, and parasomnias. Although the agreement between SDB symptoms and parasomnias was stronger for girls than for boys, the degree of concordance between SDB symptoms and parasomnia increased with preadolescent age, with the highest agreement achieved among preadolescents aged 12 years or older for SDB problems and 11 years or older for parasomnias. Findings underscore the importance of utilizing both parental and preadolescent self-reports in accurately assessing and diagnosing sleep impairment in pediatric samples.

Association between Erythrocyte Membrane Phospholipid Fatty Acids and Sleep Disturbance in Chinese Children and Adolescents

The relationship between circulating fatty acid (FA) composition and childhood sleep disturbance remains largely unclear. We aimed to investigate the association of erythrocyte membrane FA composition with prevalence of sleep disturbance in Chinese children and adolescents. A cross-sectional survey was conducted among 2337 school-aged children and adolescents who completed a clinical assessment in Beijing, China. Presence of sleep disturbance was self-reported or parent-reported by questionnaires. Erythrocyte FAs were measured by gas chromatography, and desaturase activities were estimated by FA ratios. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for sleep disturbance across FA quartiles were calculated by a logistical regression model. We found higher proportions of erythrocyte phospholipid 24:0, 24:1n-9, and lower proportions of total n-3 polyunsaturated FA (PUFA), 22:5n-3 and 22:6n-3 in participants with sleep disturbance compared with those without. In the logistical regression models, significant inverse associations were found for total n-3 PUFA, 22:5n-3 and 22:6n-3, the highest versus lowest quartile ORs and 95% CIs were 0.57 (0.40, 0.82), 0.67 (0.47, 0.97) and 0.69 (0.49, 0.96), respectively. For per 1 SD difference of proportion, OR and 95% CI of prevalence of sleep disturbance was 0.91 (0.86, 0.97) for total n-3 PUFA, 0.90 (0.82, 0.98) for 22:5n-3, and 0.92 (0.86, 0.99) for 22:6n-3, respectively. No significant association was found for saturated fatty acids, monounsaturated fatty acids, n-6 polyunsaturated fatty acids or FA ratios. The present study suggested that erythrocyte n-3 PUFAs, especially 22:5n-3 and 22:6n-3, are inversely associated with prevalence of sleep disturbance in Chinese children and adolescents.

Are gastrointestinal and sleep problems associated with behavioral symptoms of autism spectrum disorder?

Many children with autism spectrum disorder (ASD) suffer from concurrent medical symptoms, including gastrointestinal (GI) and sleeping problems. However, there is limited information on the correlation between co-morbidities and autistic behavioral symptoms. In this study, we estimated the prevalence of GI and sleep problems in Chinese ASD children, examined the impacts of GI and sleep problems on autistic behavioral symptoms, and investigated the factors associated with GI and sleep problems. The survey included 169 ASD and 172 healthy children. Data regarding demographic characteristics, GI symptoms, sleep disturbances and behavioral symptoms were collected through questionnaires. GI and sleep problems were prevalent in Chinese ASD children. Moreover, ASD children with GI symptoms reported more severe ASD core symptoms than others. Autistic children's GI symptoms were associated with maternal sleep problems during pregnancy, child's 0-6 month food sources and picky eating. ASD children with sleep disturbances had lower performance in daily living skills, social cognition, social communication and intellectual development than ASD children without sleep disturbances. Sleep disturbances were associated with extra nutrient supply during lactation and feeding, and child's picky eating. Autistic children with GI or/and sleep problems may represent clinically relevant subtypes of ASD, for which targeted treatments may be needed.

The mediating role of sleep in the fish consumption - cognitive functioning relationship: a cohort study

Greater fish consumption is associated with improved cognition among children, but the mediating pathways have not been well delineated. Improved sleep could be a candidate mediator of the fish-cognition relationship. This study assesses whether 1) more frequent fish consumption is associated with less sleep disturbances and higher IQ scores in schoolchildren, 2) such relationships are not accounted for by social and economic confounds, and 3) sleep quality mediates the fish-IQ relationship. In this cohort study of 541 Chinese schoolchildren, fish consumption and sleep quality were assessed at age 9-11 years, while IQ was assessed at age 12. Frequent fish consumption was related to both fewer sleep problems and higher IQ scores. A dose-response relationship indicated higher IQ scores in children who always (4.80 points) or sometimes (3.31 points) consumed fish, compared to those who rarely ate fish (all p < 0.05). Sleep quality partially mediated the relationship between fish consumption and verbal, but not performance, IQ. Findings were robust after controlling for multiple sociodemographic covariates. To our knowledge, this is the first study to indicate that frequent fish consumption may help reduce sleep problems (better sleep quality), which may in turn benefit long-term cognitive functioning in children.

Poorer Subjective Sleep Quality Is Related to Higher Fantasy-Induced Sexual Arousal in Women of Reproductive Age

Lack of sleep enhances erections and lubrication the next day. This raises the possibility that poorer subjective sleep quality is related to sexual arousal. To test this hypothesis, sexual arousal was elicited in 70 Portuguese women of reproductive age by means of fantasy. The level of salivary testosterone before and shortly after fantasy was determined by luminescence immunoassays. Participants completed the Pittsburgh Sleep Quality Index (PSQI), reported their sexual arousal before and during fantasy, and how anxious they were after the fantasy. The hypothesis was confirmed. Anxiety did not explain the association, but testosterone response (poststimulus minus baseline) had a slight explanatory effect.

Cohort Profile Update: The China Jintan Child Cohort Study

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.