Child and Adolescent Manganese Biomarkers and Adolescent Postural Balance in Marietta CARES Cohort Participants

BACKGROUND

Manganese (Mn) plays a significant role in both human health and global industries. Epidemiological studies of exposed populations demonstrate a dose-dependent association between Mn and neuromotor effects ranging from subclinical effects to a clinically defined syndrome. However, little is known about the relationship between early life Mn biomarkers and adolescent postural balance.

OBJECTIVES

This study investigated the associations between childhood and adolescent Mn biomarkers and adolescent postural balance in participants from the longitudinal Marietta Communities Actively Researching Exposures Study (CARES) cohort.

METHODS

Participants were recruited into CARES when they were 7-9 y old, and reenrolled at 13-18 years of age. At both time points, participants provided samples of blood, hair, and toenails that were analyzed for blood Mn and lead (Pb), serum cotinine, hair Mn, and toenail Mn. In adolescence, participants completed a postural balance assessment. Greater sway indicates postural instability (harmful effect), whereas lesser sway indicates postural stability (beneficial effect). Multivariable linear regression models were conducted to investigate the associations between childhood and adolescent Mn biomarkers and adolescent postural balance adjusted for age, sex, height-weight ratio, parent/caregiver intelligence quotient, socioeconomic status, blood Pb, and serum cotinine.

RESULTS

CARES participants who completed the adolescent postural balance assessment (n = 123 ) were 98% White and 54% female and had a mean age of 16 y (range: 13-18 y). In both childhood and adolescence, higher Mn biomarker concentrations were significantly associated with greater adolescent sway measures. Supplemental analyses revealed sex-specific associations; higher childhood Mn biomarker concentrations were significantly associated with greater sway in females compared with males.

DISCUSSION

This study found childhood and adolescent Mn biomarkers were associated with subclinical neuromotor effects in adolescence. This study demonstrates postural balance as a sensitive measure to assess the association between Mn biomarkers and neuromotor function. https://doi.org/10.1289/EHP13381.

Perfluoroalkyl substances (PFAS) and lead (Pb) as "cardiovascular disruptors" in 9-11-year-old children living in Syracuse, New York, United States

OBJECTIVE

Per- and polyfluoro-alkyl substances (PFAS) and lead (Pb) are ubiquitous environmental toxicants with apparent impact on cardiovascular disease (CVD) risk. As one possible mechanism for this increased risk, we have previously demonstrated an association between Pb exposure and heightened cardiovascular reactivity to acute psychological stress, a CVD risk factor. The present study expands this approach and considers both PFAS and Pb exposures (and the possible interaction).

METHODS

We assessed 14 serum PFAS and whole blood Pb concentrations in a sample of 9-11 year-old children (N = 291; 43.2% White, 56.8% Black; 53.5% female). We measured cardiovascular functioning at rest and during psychological stress as well as multiple indicators of subclinical CVD including resting blood pressure (BP), carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT), and left ventricular mass (LVM). Data analysis included general linear modeling as well as a non-parametric approach to study metal mixtures, specifically Bayesian Kernel Machine Regression (BKMR).

RESULTS

Significant interactions between different PFAS and with Pb suggest the importance of considering toxicant mixtures when assessing potential disruption of the cardiovascular system. The pattern of findings suggests that greater "vascular reactivity" (elevated BP and vascular resistance during acute psychological stress) was associated with higher concentrations of perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS), and Pb, but only when perfluorooctanoic acid (PFOA) was concurrently elevated. With respect to subclinical outcomes, increasing perfluorodecanoic acid (PFDA) was associated with greater cIMT (β = 0.21, p = 0.010).

CONCLUSION

To our knowledge this is the first study to consider how PFAS exposures might affect cardiovascular functioning and subclinical disease. Although a complex pattern of associations emerged, it does appear that PFAS and Pb can be classified as "cardiovascular disruptors" in children. Further research is needed to replicate these novel findings and determine whether these disruptions produce future cardiovascular disease.

Exposure to Arsenic and Subclinical Cardiovascular Disease in 9- to 11-Year-Old Children, Syracuse, New York

Importance

Studies in adults have demonstrated associations between arsenic exposure and clinical and subclinical cardiovascular disease (CVD). No studies to date have considered potential associations in children.

Objective

To examine the association between total urinary arsenic levels in children and subclinical indicators of CVD.

Design, Setting, and Participants

This cross-sectional study considered 245 children, a subset from the Environmental Exposures and Child Health Outcomes (EECHO) cohort. Children from the Syracuse, New York, metropolitan area were recruited from August 1, 2013, until November 30, 2017, with enrollment throughout the year. Statistical analysis was performed from January 1, 2022, to February 28, 2023.

Exposures

Total urinary arsenic was measured using inductively coupled plasma mass spectrometry. Creatinine concentration was used to adjust for urinary dilution. In addition, potential exposure routes (eg, diet) were measured.

Main Outcomes and Measures

Three indicators of subclinical CVD were assessed: carotid-femoral pulse wave velocity, carotid intima media thickness, and echocardiographic measures of cardiac remodeling.

Results

The study sample included 245 children aged 9 to 11 years (mean [SD] age, 10.52 [0.93] years; 133 [54.3%] female). The geometric mean of the creatinine-adjusted total arsenic level in the population was 7.76 μg/g creatinine. After adjustment for covariates, elevated total arsenic levels were associated with significantly greater carotid intima media thickness (β = 0.21; 95% CI, 0.08-0.33; P = .001). In addition, echocardiography revealed that elevated total arsenic was significantly higher for children with concentric hypertrophy (indicated by greater left ventricular mass and greater relative wall thickness; geometric mean, 16.77 μg/g creatinine; 95% CI, 9.87-28.79 μg/g) relative to the reference group (geometric mean, 7.39 μg/g creatinine; 95% CI, 6.36-8.58 μg/g). With respect to exposure source, significant geographic clustering of total arsenic was found in 1 urban area of Syracuse, New York.

Conclusions and Relevance

These findings suggest a significant association between arsenic exposure and subclinical CVD in children. Elevated total arsenic levels were found in an area of Syracuse with known elevations of toxic metals from industrial waste, suggesting historical pollution as a possible source. Given the novelty and potential importance of this association, further research is needed to confirm our findings. Any potential effect of urinary arsenic exposure in childhood on actual clinical CVD outcomes in adulthood remains to be determined.

Airborne levels of cadmium are correlated with urinary cadmium concentrations among young children living in the New York state city of Syracuse, USA

Air pollution is a serious public health issue with early childhood exposure being of high concern because of the greater risk that children might experience negative health outcomes. Industrial sources in and near communities are one potential path of exposure that children might face with greater levels of air pollution correlating with higher levels of toxicants detected in children. We compare estimated ambient air concentrations of Cadmium (Cd) to a cohort (n = 281) of 9 to 11-year old children during their early childhood years (0-5 years of age) in a mid-size city in Upstate New York. Levels of Cd air pollution are compared to children's urine-Cd levels. Urine has been shown to be a superior biomarker to blood for Cd exposure particularly for longer-term exposures. We find that participants who reside in households that faced greater Cd air pollution during the child's early years have higher urine-Cd levels. This association is stable and stronger than previously presented associations for blood-Cd. Findings support expanded use of air modelling data for risk screening to reduce the potential health burden that industrial pollution can have.

The Inflammation Biomarker GlycA Reflects Plasma N-Glycan Branching

BACKGROUND

GlycA is a nuclear magnetic resonance (NMR) signal in plasma that correlates with inflammation and cardiovascular outcomes in large data sets. The signal is thought to originate from N-acetylglucosamine (GlcNAc) residues of branched plasma N-glycans, though direct experimental evidence is limited. Trace element concentrations affect plasma glycosylation patterns and may thereby also influence GlycA.

METHODS

NMR GlycA signal was measured in plasma samples from 87 individuals and correlated with MALDI-MS N-glycomics and trace element analysis. We further evaluated the genetic association with GlycA at rs13107325, a single nucleotide polymorphism resulting in a missense variant within SLC39A8, a manganese transporter that influences N-glycan branching, both in our samples and existing genome-wide association studies data from 22 835 participants in the Women's Health Study (WHS).

RESULTS

GlycA signal was correlated with both N-glycan branching (r2 ranging from 0.125-0.265; all P < 0.001) and copper concentration (r2 = 0.348, P < 0.0001). In addition, GlycA levels were associated with rs13107325 genotype in the WHS (β [standard error of the mean] = -4.66 [1.2674], P = 0.0002).

CONCLUSIONS

These results provide the first direct experimental evidence linking the GlycA NMR signal to N-glycan branching commonly associated with acute phase reactive proteins involved in inflammation.

Environmental exposures to pesticides, phthalates, phenols and trace elements are associated with neurodevelopment in the CHARGE study

OBJECTIVE

To determine if higher exposures measured in early childhood to environmental phenols, phthalates, pesticides, and/or trace elements, are associated with increased odds of having a diagnosis of Autism Spectrum Disorder (ASD), Developmental Delay (DD), or Other Early Concerns (OEC) compared to typically developing children (TD).

METHODS

This study included 627 children between the ages of 2-5 who participated in the Childhood Autism Risks from Genetics and Environment (CHARGE) study. Urine samples were collected at the same study visit where diagnostic assessments to confirm diagnosis indicated during the recruitment process were performed. Adjusted multinomial regression models of each chemical with diagnosis as the outcome were conducted. Additionally, two methods were used to analyze mixtures: repeated holdout multinomial weighted quantile sum (WQS) regression for each chemical class; and a total urinary mixture effect was assessed with repeated holdout random subset WQS.

RESULTS

Many urinary chemicals were associated with increased odds of ASD, DD or OEC compared to TD; however, most did not remain significant after false discovery rate adjustment. Repeated holdout WQS indices provided evidence for associations of both a phenol/paraben mixture effect and a trace element mixture effect on DD independently. In analyses adjusted for confounders and other exposures, results suggested an association of a pesticide mixture effect with increased risk for ASD. Results also suggested associations of a total urinary mixture with greater odds of both ASD and DD separately.

CONCLUSION

Higher concentrations of urinary biomarkers were associated with ASD, DD, and OEC compared to TD, with consistency of the results comparing single chemical analyses and mixture analyses. Given that the biospecimens used for chemical analysis were generally collected many months after diagnoses were made, the direction of any causal association is unknown. Hence findings may reflect higher exposures among children with non-typical development than TD children due to differences in behaviors, metabolism, or toxicokinetics.

Biomonitoring of exposure to Great Lakes contaminants among licensed anglers and Burmese refugees in Western New York: Toxic metals and persistent organic pollutants, 2010-2015

Between 2010 and 2015, the New York State Department of Health (NYSDOH) conducted a biomonitoring program to gather exposure data on Great Lakes contaminants among licensed anglers and Burmese refugees living in western New York who ate locally caught fish. Four hundred and nine adult licensed anglers and 206 adult Burmese refugees participated in this program. Participants provided blood and urine samples and completed a detailed questionnaire. Herein, we present blood metal levels (cadmium, lead, and total mercury) and serum persistent organic pollutant concentrations [polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dichlorodiphenyldichloroethylene (DDE), and trans-nonachlor]. Multiple linear regression was applied to investigate the associations between analyte concentrations and indicators of fish consumption (locally caught fish meals, store-bought fish meals, and consuming fish/shellfish in the past week). Licensed anglers consumed a median of 16 locally caught fish meals and 22 store-bought fish meals while Burmese refugees consumed a median of 106 locally caught fish meals and 104 store-bought fish/shellfish meals in the past year. Compared to the general U.S. adult population, licensed anglers had higher blood lead and mercury levels; and Burmese refuges had higher blood cadmium, lead, and mercury, and higher serum DDE levels. Eating more locally caught fish was associated with higher blood lead, blood mercury, and serum ∑PCBs concentrations among licensed anglers. Licensed anglers and Burmese refugees who reported fish/shellfish consumption in the past week had elevated blood mercury levels compared with those who reported no consumption. Among licensed anglers, eating more store-bought fish meals was also associated with higher blood mercury levels. As part of the program, NYSDOH staff provided fish advisory outreach and education to all participants on ways to reduce their exposures, make healthier choices of fish to eat, and waters to fish from. Overall, our findings on exposure levels and fish consumption provide information to support the development and implementation of exposure reduction public health actions.

Co-exposure to manganese and lead and pediatric neurocognition in East Liverpool, Ohio

Exposure to metal mixtures may lead to health impacts greater than the effects associated with singular exposures. Two common childhood environmental exposures, manganese (Mn) and lead (Pb), are associated with similar adverse neurodevelopmental effects; however, the effects surrounding concurrent exposure to both metals remain unclear. We study the impact of joint exposure to Mn and Pb on cognitive performance in school-aged children participating in the Communities Actively Researching Exposure Study (CARES) based in East Liverpool, Ohio. Blood Pb levels were measured for each child (geometric mean (GM) = 1.13 μg/dL, range 0.30 μg/dL - 6.64 μg/dL). Mn was measured in participant blood, hair, and toenails with GMs of 10.1 μg/L, 360 ng/g, 0.974 μg/g, respectively. Trained team members administered the Wechsler Intelligence Scale for Children-IV (WISC-IV) to assess intelligence quotient (IQ). The WISC-IV provides scores for Full Scale IQ, Perceptual Reasoning, Processing Speed, Working Memory, and Verbal Comprehension. Interactions between blood Pb and all Mn biomarkers were tested in linear models adjusted for child sex, household income, and serum cotinine. Separate regression models were run for each of the Mn biomarkers. The cohort was comprised of 106 children with a mean age of 8.4 years. Interactions between blood Pb and hair Mn were significant (p < 0.05) for four out of the five IQ domains. The effect of blood Pb on IQ was more pronounced at higher levels of hair and toenail Mn. No significant associations were observed when characterizing the main effect of Mn using blood. Uncovering the health impacts associated with exposure mixtures is critical to understanding the impact of real-life conditions. Our findings suggest that joint exposure to Mn and Pb may produce heightened neurocognitive impacts even at blood Pb levels below the CDC reference concentration of 5 μg/dL.

Linking metal (Pb, Hg, Cd) industrial air pollution risk to blood metal levels and cardiovascular functioning and structure among children in Syracuse, NY

BACKGROUND

Exposure to air pollution has been linked to individual health effects in occupational environments and communities proximate to air pollution sources. Use of estimated chemical concentrations from the Risk Screening Environmental Indicators (RSEI) model, derived from the Toxics Release Inventory, can help approximate some contributions to individual lifetime exposure to risk from air pollution and holds potential for linkages with specific health outcome data.

OBJECTIVES

Our objectives were: (1) use regression modeling to test for associations between observed blood metal concentrations in children and RSEI total air concentrations of the same metals released from proximate manufacturing facilities; (2) determine the relative contribution of RSEI air pollution to blood metal concentrations; and (3) examine associations between chronic metal exposure and cardiovascular functioning and structure in study participants.

METHODS

Using data synthesis methods and regression modeling we linked individual blood-based levels of lead, mercury, and cadmium(Pb, Hg, Cd) and cardiovascular functioning and structure to proximate industrial releases of the same metals captured by the Environmental Protection Agency's (EPA) RSEI geographic microdata.

RESULTS

We found that RSEI-derived ground-level ambient air concentrations of Hg and Cd were a significant predictor of blood metal levels, when controlling for covariates and other exposure variables. In addition to associations with blood metal findings, RSEI concentrations also predicted cardiovascular dysfunction and risk including changes in left-ventricular mass, blood pressure, and heart rate.

DISCUSSION

Right-to-know data, such as EPA's RSEI, can be linked to objective health outcomes, rather than simply serving as a non-specific risk estimate. These data can serve as a proxy for hazard exposure and should be used more widely to understand the dynamics of environmental exposure. Furthermore, since these data are both a product of and contribute to regulatory decision making, they could serve as an important link between disease risk and translation-orientated national environmental health policy.

Measurement harmonization and traceability for trace element analyses across the Children's Health Exposure Analysis Resource laboratory network

Harmonization and traceability are related metrological principles that are indispensable to assuring measurement comparability across different biomonitoring studies. The Children's Health Exposure Analysis Resource (CHEAR) was established in 2015 with six laboratories providing environmental exposure measurements on biospecimens. To ensure harmonization across studies for trace elements, CHEAR used a multi-faceted approach that included: 1) an initial interlaboratory validation exercise based on the analysis of certified blood and urine reference materials; 2) frequent participation in an established interlaboratory proficiency program for trace elements; and 3) analysis of a common pool of well-characterized biological reference materials with each analytical batch. Method accuracy and precision were established for each laboratory via analysis of NIST SRM 955c Toxic Elements in Caprine Blood, SRM 2668 Toxic Elements in Frozen Human Urine and SRM 3668 Mercury, Perchlorate, and Iodide in Frozen Human Urine. The differences among the six laboratories for As, Cd, Hg, and Mn in urine and Cd, Hg, and Pb in whole blood were judged to be fit-for-purpose. Interlaboratory performance over a 5-year period demonstrated an improvement in performance, such that for 2018-2019, >99% of challenges for urine As, Cd, Hg, and Mn, and 95% for whole blood Cd, Hg, Pb, and Mn, were found to be satisfactory. The CHEAR common reference materials were analyzed by at least 5 laboratories for 22 elements in urine and 13-14 elements in whole blood, thus providing a rich source of data to assess intra- and inter-run performance. The suite of trace elements with assigned values in both blood and urine matrices are more comprehensive than similar reference materials from other sources, and is reflective of the concentrations necessary to support biomonitoring studies. While some areas for future improvement were identified, significant progress was made to improve harmonization of trace element measurements in biological matrices among the CHEAR network labs.

The schizophrenia risk locus in SLC39A8 alters brain metal transport and plasma glycosylation

A common missense variant in SLC39A8 is convincingly associated with schizophrenia and several additional phenotypes. Homozygous loss-of-function mutations in SLC39A8 result in undetectable serum manganese (Mn) and a Congenital Disorder of Glycosylation (CDG) due to the exquisite sensitivity of glycosyltransferases to Mn concentration. Here, we identified several Mn-related changes in human carriers of the common SLC39A8 missense allele. Analysis of structural brain MRI scans showed a dose-dependent change in the ratio of T2w to T1w signal in several regions. Comprehensive trace element analysis confirmed a specific reduction of only serum Mn, and plasma protein N-glycome profiling revealed reduced complexity and branching. N-glycome profiling from two individuals with SLC39A8-CDG showed similar but more severe alterations in branching that improved with Mn supplementation, suggesting that the common variant exists on a spectrum of hypofunction with potential for reversibility. Characterizing the functional impact of this variant will enhance our understanding of schizophrenia pathogenesis and identify novel therapeutic targets and biomarkers.

Dietary contributions to increased background lead, mercury, and cadmium in 9-11 Year old children: Accounting for racial differences

BACKGROUND

Initial interest in the adverse consequences of exposure to lead (Pb), mercury (Hg), and cadmium (Cd) focused on relatively high exposures through environmental or occupational sources; however, recent evidence suggests even low-level background exposure to non-essential metals might be detrimental, particularly for children's health and development. One potentially important source of increased background levels of non-essential toxic metals is diet.

OBJECTIVES

We considered whether differences in diet are associated with levels of non-essential metals in blood and whether racial differences in metals are mediated by dietary differences.

METHODS

We assessed blood levels of Pb, Hg, and Cd in a sample of 9-11 year-old children (N = 295) comprised of 42% European Americans (EAs), 58% African American (AAs), and 47% female. Diet was assessed using 24-h dietary recalls during phone interviews administered to parents on two consecutive days (Friday and Saturday). The Healthy Eating Index-2105 (HEI-2015) was calculated to assess diet quality.

RESULTS

The current study identified significant dietary sources of non-essential metal exposure - namely total fruit for Pb, total protein for Hg, and greens and beans for Cd. Moreover, AAs were found to have significantly higher blood levels of Pb and Hg than EAs and these racial differences were significantly mediated by these dietary differences.

DISCUSSION

This study is one of very few to consider total diet in children and exposure to the non-essential metals Pb, Hg, and Cd, and the first to demonstrate that racial differences in increased background blood levels of non-essential toxic metals can be accounted for by racial differences in diet. Given regional differences in food consumption patterns and specific farm and store sources for the foods, the generalizability of the current findings has yet to be determined; however, commonly consumed foods appear to be a significant source of low-level non-essential metals.

Evaluating associations between early pregnancy trace elements mixture and 2nd trimester gestational glucose levels: A comparison of three statistical approaches

OBJECTIVE

Studies have shown that individual trace element levels might be associated with abnormal glycemic status, with implications for diabetes. Few studies have considered these trace elements as a mixture and their impact on gestational glucose levels. Comparing three statistical approaches, we assessed the associations between essential trace elements mixture and gestational glucose levels.

METHODS

We used data from 1720 women enrolled in the Eunice Kennedy Shriver National Institute of Child Health and Human Development's Fetal Growth Study, for whom trace element concentrations (zinc, selenium, copper, molybdenum) were measured by inductively coupled plasma mass spectrometry (ICP-MS) using plasma collected during the 1st trimester. Non-fasting glucose levels were measured during the gestational diabetes mellitus (GDM) screening test in the 2nd trimester. We applied (1) Bayesian Kernel Machine Regression (BKMR); (2) adaptive Least Absolute Shrinkage and Selection Operator (LASSO) in a mutually adjusted linear regression model; and (3) generalized additive models (GAMs) to evaluate the joint associations between trace elements mixture and glucose levels adjusting for potential confounders.

RESULTS

Using BKMR, we observed a mean 2.7 mg/dL higher glucose level for each interquartile increase of plasma copper (95% credible interval: 0.9, 4.5). The positive association between plasma copper and glucose levels was more pronounced at higher quartiles of zinc. Similar associations were detected using adaptive LASSO and GAM. In addition, results from adaptive LASSO and GAM suggested a super-additive interaction between molybdenum and selenium (both p-values = 0.04).

CONCLUSION

Employing different statistical methods, we found consistent evidence of higher gestational glucose levels associated with higher copper and potential synergism between zinc and copper on glucose levels.

A comparison of blood and toenails as biomarkers of children's exposure to lead and their correlation with cognitive function

This study sought to compare lead (Pb) concentrations in toenails and blood and to investigate the association of each biomarker with children's cognitive function. Toenails and whole blood samples were collected from 224 twelve-year-old children, and their full-scale intelligence quotient (FSIQ) was assessed using the Wechsler Intelligence Scale for Children-4th edition. Inductively coupled plasma-mass spectrometry was used to determine blood (BPb) and toenail (TPb) Pb concentrations. Log BPb and Log TPb were significantly correlated (r² = 0.49, p < 0.001). In unadjusted analyses, both log-transformed BPb and TPb were significantly associated with decreased FSIQ, but BPb accounted for approximately quadruple the FSIQ scores' variability than log-transformed TPb (model R² = 0.12 and R² = 0.03, respectively). After adjusting for neighborhood deprivation, caregiver intelligence (assessed with the Wechsler Abbreviated Scale of Intelligence-2nd edition), and child BMI, BPb remained significantly associated with decreased FSIQ, while TPb did not (p = 0.16). These results suggest that while concentrations of Pb in blood and toenails are correlated, TPb does not predict cognitive outcomes at these exposure levels. With caution and in conjunction with BPb, TPb may be used as a population-based biomarker of Pb exposure.

Coal smoke, gestational cadmium exposure, and fetal growth

BACKGROUND

Gestational cadmium exposure may impair fetal growth. Coal smoke has largely been unexplored as a source of cadmium exposure. We investigated the relationship between gestational cadmium exposure and fetal growth, and assessed coal smoke as a potential source of airborne cadmium, among non-smoking pregnant women in Ulaanbaatar, Mongolia, where coal combustion in home heating stoves is a major source of outdoor and indoor air pollution.

METHODS

This observational study was nested within the Ulaanbaatar Gestation and Air Pollution Research (UGAAR) study, a randomized controlled trial of portable high efficiency particulate air (HEPA) filter air cleaner use during pregnancy, fetal growth, and early childhood development. We measured third trimester blood cadmium concentrations in 374 out of 465 participants who had a live birth. We used multiple linear and logistic regression to assess the relationships between log₂-transformed maternal blood cadmium concentrations and birth weight, length, head circumference, ponderal index, low birth weight, small for gestational age, and preterm birth in crude and adjusted models. We also evaluated the relationships between log₂-transformed blood cadmium concentrations and the density of coal-burning stoves within 5000 m of each participant's apartment as a proxy of coal smoke emissions from home heating stoves.

RESULTS

The median (25th,75th percentile) blood cadmium concentration was 0.20 (0.15, 0.29) μg/L. A doubling of blood cadmium was associated with a 95 g (95% CI: 34, 155 g) reduction in birth weight in adjusted models. An interquartile range increase in coal stove density (from 3.4 to 4.9 gers/hectare) surrounding participants' apartments was associated with a 12.2% (95% CI: 0.3, 25.6%) increase in blood cadmium concentrations.

CONCLUSIONS

Gestational cadmium exposure was associated with reduced birth weight. In settings where coal is a widely used fuel, cadmium may play a role in the putative association between air pollution and impaired fetal growth.

Biomonitoring of populations in Western New York at risk for exposure to Great Lakes contaminants

The New York State Department of Health conducted the Healthy Fishing Communities Program in collaboration with the Agency for Toxic Substances and Disease Registry to assess human exposure to contaminants common to Lake Ontario, Lake Erie and surrounding rivers and waterways among populations in western New York State who eat locally caught fish. The program enrolled licensed anglers and Burmese refugees and immigrants, living near four designated Great Lakes Areas of Concern: Buffalo River, Niagara River, Eighteenmile Creek, and the Rochester Embayment. These target populations were sampled and enrolled independently into the program between February and October of 2013. A core set of contaminants were measured in blood and urine of 409 licensed anglers and 206 Burmese refugees and immigrants which included lead, cadmium, mercury, PCBs, PBDEs, organochlorine pesticides (hexachlorobenzene, mirex, DDT, DDE, and chlordane and its metabolites oxychlordane and trans-Nonachlor), and PFOS and PFOA. Biomonitoring results showed that both groups had higher geometric means for blood lead, total blood mercury, and serum PFOS compared to the 2013-2014 NHANES reference levels. The Burmese refugee group also showed higher geometric means for creatinine-adjusted urine mercury and lipid-adjusted serum DDE compared to national levels. Licensed angler participants reported eating a median of 16 locally caught fish meals in the past year. Burmese participants consumed local fish throughout the year, and most frequently in the summer (median 39 fish meals or 3 times a week). The study results provide valuable information on populations at high risk of exposure to contaminants in the Great Lakes Basin of western New York. The results provide the foundation for developing and implementing public health actions to reduce potential exposures to Great Lakes pollutants.

A Prospective Study of Early Pregnancy Essential Metal(loid)s and Glucose Levels Late in the Second Trimester

CONTEXT

Studies suggest many essential trace metal(loid)s are involved in glucose metabolism, but the associations among pregnant women are unclear.

OBJECTIVE

To assess associations between early pregnancy plasma zinc, selenium, copper, and molybdenum levels and blood glucose levels later in the second trimester.

DESIGN

The Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies‒Singleton Cohort is a prospective cohort study conducted between July 2009 and January 2013.

SETTING

Twelve academic research hospitals in the United States.

PATIENTS

A total of 1857 multiracial, nonobese, healthy women.

MAIN OUTCOME MEASURE

Blood glucose levels from 1-hour 50-g gestational load test (GLT) at 24 to 28 weeks of gestation.

RESULTS

Higher concentrations of first-trimester copper were associated with higher glucose levels from the GLT (i.e., every 50% increase in copper concentration was related to 4.9 mg/dL higher glucose level; 95% CI: 2.2, 7.5 mg/dL) adjusted for maternal sociodemographic characteristics and reproductive history. In contrast, every 50% increase in molybdenum concentration was associated with 1.2 mg/dL lower mean glucose level (95% CI: -2.3, -0.1 mg/dL). The magnitude of these associations was greater at the upper tails of glucose level distribution based on quantile regressions of the 10th, 50th, and 90th percentiles.

CONCLUSIONS

Higher copper and lower molybdenum concentrations could increase the risk of glucose dysregulation during pregnancy, with women at higher risk of gestational diabetes mellitus potentially affected to a greater extent. Further work is needed to understand the mechanisms involved with early pregnancy essential metal(loid)s to inform clinical diagnosis and prevention of glucose intolerance during pregnancy.

Variability in the spatial density of vacant properties contributes to background lead (Pb) exposure in children

BACKGROUND

Heightened blood lead levels (BLL) are associated with cognitive deficiencies and adverse behavioral outcomes. Lead-contaminated house dust is the primary source of exposure in U.S. children, and evidence suggests that even background (low-level) exposure has negative consequences. Identifying sources of background exposure is of great public health significance because of the larger number of children that can be affected.

METHODS

Blood lead was assessed in a bi-racial sample of children from Syracuse, NY, aged 9-11, using established biomonitoring methods. The spatial density of vacant properties was modelled from publicly available georeferenced datasets. Further, regression models were used to measure the impact of this spatial density variable on children's BLL.

RESULTS

In a sample of 221 children, with a mean BLL of 1.06 µg/dL (SD = 0.68), results showed increases in spatial density of vacant properties predict increases in median blood-PB levels, b = 0.14 (0.06-0.21), p < .001. This association held true even after accounting for demographic covariates, and age of individual housing. Further analysis showed spatial autocorrelation of the residuals changed from a clustered pattern to a random pattern once the spatial density variable was introduced to the model.

DISCUSSION

This study is the first to identify a background-lead exposure source using spatial density modelling. As vacant properties deteriorate, lead-contaminated dust likely disperses into the surrounding environment. High-density areas have an accumulation of lead hazards in environmental media, namely soil and dust, putting more children at risk of exposure.

Tracking Declines in Mercury Exposure in the New York City Adult Population, 2004-2014

Mercury is a toxic metal that can be measured in human blood and urine. Population-based biomonitoring from 2004 guided New York City (NYC) Department of Health and Mental Hygiene (DOHMH) efforts to reduce exposures by educating the public about risks and benefits of fish consumption-a predominant source of exposure in the general population-and removing mercury-containing skin-lightening creams and other consumer products from the marketplace. We describe changes in exposures over the past decade in relation to these local public health actions and in the context of national changes by comparing mercury concentrations measured in blood (1201 specimens) and urine (1408 specimens) from the NYC Health and Nutrition Examination Survey (NYC HANES) 2013-2014 with measurements from NYC HANES 2004 and National Health and Nutrition Examination Surveys (NHANES) 2003-2004 and 2013-2014. We found that NYC adult blood and urine geometric mean mercury concentrations decreased 46% and 45%, respectively. Adult New Yorkers with blood mercury concentration ≥ 5 μg/L (the New York State reportable level) declined from 24.8% (95% CL = 22.2%, 27.7%) to 12.0% (95% CL = 10.1%, 14.3%). The decline in blood mercury in NYC was greater than the national decline, while the decline in urine mercury was similar. As in 2004, Asian New Yorkers had higher blood mercury concentrations than other racial/ethnic groups. Foreign-born adults of East or Southeast Asian origin had the highest prevalence of reportable levels (29.7%; 95% CL = 21.0%, 40.1%) across sociodemographic groups, and Asians generally were the most frequent fish consumers, eating on average 11 fish meals in the past month compared with 7 among other groups (p < 0.001). Fish consumption patterns were similar over time, and fish continues to be consumed more frequently in NYC than nationwide (24.7% of NYC adults ate fish ten or more times in the past 30 days vs. 14.7% nationally, p < 0.001). The findings are consistent with the hypothesis that blood mercury levels have declined in part because of local and national efforts to promote consumption of lower mercury fish. Local NYC efforts may have accelerated the reduction in exposure. Having "silver-colored fillings" on five or more teeth was associated with the highest 95th percentile for urine mercury (4.06 μg/L; 95% CL = 3.1, 5.9). An estimated 5.5% of the adult population (95% CL = 4.3%, 7.0%) reported using a skin-lightening cream in the past 30 days, but there was little evidence that use was associated with elevated urine mercury in 2013-14.

Declines in adult blood lead levels in New York City compared with the United States, 2004-2014

OBJECTIVES

To assess changes in lead exposure in the New York City (NYC) adult population over a 10-year period and to contrast changes with national estimates, overall, and by socio-demographics and smoking status.

METHODS

We used measurements of blood lead levels (BLLs) from NYC resident adults who participated in the NYC Health and Nutrition Examination Surveys (HANES) in 2004 and 2013-2014. We compared estimates of geometric means (GM), 95th percentiles, and prevalence of BLL ≥ 5 µg/dL overall and by subgroups over time, with adults who participated in the National HANES (NHANES) 2001-2004 and 2011-2014.

RESULTS

The GM BLLs among NYC adults declined from 1.79 µg/dL in 2004 to 1.13 µg/dL in 2013-2014 (P < .0001). The declines over this period ranged from 30.1% to 43.2% across socio-demographic groups and smoking status (P < .0001 for all comparisons), and were slightly greater than declines observed nationally. The drop in prevalence of elevated BLLs (≥ 5 µg/dL) was also greater in NYC (4.8-0.5%), compared with NHANES (3.8-2.0%). By 2013-2014, NYC adults with lower annual family income (< $20,000) no longer had higher GM BLLs relative to those with higher incomes (≥ $75,000), a disparity improvement not observed nationally. Likewise, GM BLLs and 95th percentiles for non-Hispanic black adults in NYC were lower than GM BLLs for non-Hispanic white adults. Non-Hispanic Asian adults had the highest GM BLLs compared with other racial/ethnic groups, both in NYC in 2013-14 and nationally in 2011-2014 (1.37 µg/dL, P = .1048 and 1.22 µg/dL, P = .0004, respectively).

CONCLUSION

The lessening of disparity in lead exposure across income groups and decreasing exposure at the high end of the distribution among non-Hispanic black and Asian adults in NYC suggest that regulatory and outreach efforts have effectively targeted these higher exposure risk groups. However, Asian adults still had the highest average BLL, suggesting a need for enhanced outreach to this group. Local surveillance remains an important tool to monitor BLLs of local populations and to inform initiatives to reduce exposures in those at highest risk.

The effect of portable HEPA filter air cleaners on indoor PM2.5 concentrations and second hand tobacco smoke exposure among pregnant women in Ulaanbaatar, Mongolia: The UGAAR randomized controlled trial

BACKGROUND

Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM_2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM_2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia.

METHODS

We randomized 540 participants to an intervention group receiving 1 or 2 HEPA filter air cleaners or a control group receiving no air cleaners. We followed 259 intervention and 253 control participants to the end of pregnancy. We measured one-week indoor residential PM_2.5 concentrations in early (~11weeks gestation) and late (~31weeks gestation) pregnancy and collected outdoor PM_2.5 data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness.

RESULTS

The overall geometric mean (GM) one-week outdoor PM_2.5 concentration was 47.9μg/m³ (95% CI: 44.6, 51.6μg/m³), with highest concentrations in winter (118.0μg/m³; 110.4, 126.2μg/m³). One-week indoor and outdoor PM_2.5 concentrations were correlated (r=0.69). Indoor PM_2.5 concentrations were 29% (21, 37%) lower in intervention versus control apartments, with GMs of 17.3μg/m³ (15.8, 18.8μg/m³) and 24.5μg/m³ (22.2, 27.0μg/m³), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure.

CONCLUSIONS

Portable HEPA filter air cleaners can lower indoor PM_2.5 concentrations and SHS exposures in highly polluted settings.

Background lead and mercury exposures: Psychological and behavioral problems in children

BACKGROUND

The potential harm from exposure to nonessential metals, particularly mercury (Hg) and lead (Pb), has been the focus of research for years. Initial interest focused on relatively high exposures; however, recent evidence suggests that even background exposures might have adverse consequences for child development. Identifying the extent of these consequences is now a priority.

METHODS

We assessed blood Pb and Hg levels in a biracial sample of 9-11 year-old children (N = 203). Neurodevelopment and psychological functioning assessments included hostility, disruptive behaviors, emotion regulation, and autism spectrum disorder behaviors. Parasympathetic (vagal) responses to acute stress were indexed by heart rate variability (HRV) at rest and during stress.

RESULTS

With increasing Pb levels, children exhibit higher levels of hostile distrust and oppositional defiant behaviors, were more dissatisfied and uncertain about their emotions, and had difficulties with communication. These significant associations were found within a range of blood Pb levels from 0.19 to 3.25μg/dL, well below the "reference value" for children of >5μg/dL. Vagal reactivity interacted with Hg such that increasing Hg was associated with increasing autism spectrum behaviors for those children with sustained vagal tone during acute stress.

CONCLUSIONS

This study is the first to demonstrate an association between very low-level Pb exposure and fundamental psychological mechanisms that might explain prior associations with more complex outcomes such as delinquency. Analyses of vagal reactivity yielded entirely novel associations suggesting that Hg may increase autism spectrum behaviors in children with sustained vagal tone during acute stress. The novelty of these later findings requires additional research for confirmation and the cross-sectional nature of the data caution against assumptions of causality without further research.

Community Engagement and Data Disclosure in Environmental Health Research

Federal funding agencies increasingly support stakeholder participation in environmental health studies, and yet there is very little published research on engagement of community members in the development of data disclosure (DD) strategies. The Ohio Environmental Protection Agency reported airborne manganese (Mn) concentrations in East Liverpool, Ohio, 30 times higher than the reference concentration, which led to an academic–community research partnership to address community concern about Mn exposure, particularly among children. Children and their families were recruited to participate in a pilot study. Samples of blood and hair were collected from the children and analyzed for metals. DD mechanisms were developed using an iterative approach between community and academic partners. Individual DD letters were mailed to each participating family, and a community meeting was held. A post-meeting survey was administered to gauge community perception of the DD strategies. The purpose of this article is to demonstrate the effectiveness of engaging community partners in the conduct of environmental health research and in the development of DD strategies for individuals and the community at large. Scientists should include community partners in the development of DD strategies to enhance translation of the research findings and support the right of study participants to know their individual results.

Changes in low levels of lead over the course of pregnancy and the association with birth outcomes

Data are lacking on the effect of low level prenatal lead exposure. We examined the change in blood lead from the second trimester until delivery and the association between maternal and cord blood lead and birth outcomes in 98 participants of the CANDLE birth cohort study. Mixed effects models were constructed to assess blood lead change over pregnancy and regression models were used to explore the relationship with cord blood lead, characteristics effecting maternal lead, birth weight and gestational age. Overall, the geometric mean maternal blood level was 0.43 μg/dL. Maternal blood lead at each time point was predictive of cord blood lead level. A 0.1 μg/dL increase in second trimester lead was associated with lower birth weight and pre-term birth. Maternal blood lead below 1 μg/dL behaves in a manner similar to lead at higher levels and is associated with a small decrease in birth weight and gestational age.

Low-level mercury in children: associations with sleep duration and cytokines TNF-α and IL-6

There is a sizeable literature suggesting that mercury (Hg) exposure affects cytokine levels in humans. In addition to their signaling role in the immune system, some cytokines are also integrally associated with sleep behavior. In this cross-sectional study of 9-11 year old children (N=100), we measured total blood Hg in whole blood, serum levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), and objectively measured sleep and activity using actigraphy. Increasing blood Hg was associated with significantly shorter sleep duration and lower levels of TNF-α. IL-6 was not associated with sleep or blood Hg. This study is the first to document an association between total blood Hg and sleep (albeit a small effect), and the first to consider the associations of total blood Hg with cytokines TNF-α and IL-6 in a pediatric sample. Further research using alternative designs (e.g., time-series) is necessary to determine if there is a causal pathway linking low-level Hg exposure to sleep restriction and reduced cytokines.

Maternal mercury exposure, season of conception and adverse birth outcomes in an urban immigrant community in Brooklyn, New York, U.S.A

Adverse birth outcomes including preterm birth (PTB: <37 weeks gestation) and low birth weight (LBW: <2500 g) can result in severe infant morbidity and mortality. In the United States, there are racial and ethnic differences in the prevalence of PTB and LBW. We investigated the association between PTB and LBW with prenatal mercury (Hg) exposure and season of conception in an urban immigrant community in Brooklyn, New York. We recruited 191 pregnant women aged 18-45 in a Brooklyn Prenatal Clinic and followed them until delivery. Urine specimens were collected from the participants during the 6th to 9th month of pregnancy. Cord blood specimens and neonate anthropometric data were collected at birth. We used multivariate logistic regression models to investigate the odds of LBW or PTB with either maternal urinary mercury or neonate cord blood mercury. We used linear regression models to investigate the association between continuous anthropometric outcomes and maternal urinary mercury or neonate cord blood mercury. We also examined the association between LBW and PTB and the season that pregnancy began. Results showed higher rates of PTB and LBW in this cohort of women compared to other studies. Pregnancies beginning in winter (December, January, February) were at increased odds of LBW births compared with births from pregnancies that began in all other months (OR7.52 [95% CI 1.65, 34.29]). We observed no association between maternal exposure to Hg, and either LBW or PTB. The apparent lack of association is consistent with other studies. Further examination of seasonal association with LBW is warranted.

Increased urinary cobalt and whole blood concentrations of cadmium and lead in women with uterine leiomyomata: Findings from the ENDO Study

Multiple trace elements have estrogen receptor activity, but the association of these elements with uterine leiomyoma has not been defined. A cohort of 473 women aged 18-44 undergoing surgery for benign gynecologic indications provided whole blood and urine specimens for trace element analysis, which was performed by inductively coupled plasma mass spectrometry. Twenty elements were analyzed in blood and 3 in urine. The surgeon documented whether fibroids were present. Geometric mean concentrations were compared between women with and without fibroids, and logistic regression models were generated to assess the impact of the concentration of each trace element on the odds of fibroids. In multivariate regressions, odds of a fibroid diagnosis were higher with increased whole blood cadmium (AOR 1.44, 95% CI 1.02, 2.04) and lead (AOR 1.31 95% CI 1.02, 1.69), and urine cobalt (AOR 1.31, 95% CI 1.02, 1.70). Urinary cadmium and lead were not related to fibroid diagnosis. Increased exposure to trace elements may contribute to fibroid growth, and fibroids may serve as a reservoir for these elements. Differences between urinary and whole blood findings merit further investigation, as urinary cadmium has been considered a superior marker of exposure.

Childhood exposure to manganese and postural instability in children living near a ferromanganese refinery in Southeastern Ohio

Airborne manganese (Mn) exposure can result in neurotoxicity and postural instability in occupationally exposed workers, yet few studies have explored the association ambient exposure to Mn in children and postural stability. The goal of this study was to determine the association between Mn and lead (Pb) exposure, as measured by blood Pb, blood and hair Mn and time weighted distance (TWD) from a ferromanganese refinery, and postural stability in children. A subset of children ages 7-9 years enrolled in the Marietta Community Actively Researching Exposure Study (CARES) were invited to participate. Postural balance was conducted on 55 children residing in Marietta, Ohio and the surrounding area. Samples of blood were collected and analyzed for Mn and Pb, and samples of hair were analyzed for Mn. Neuromotor performance was assessed using postural balance testing with a computer force platform system. Pearson correlations were calculated to identify key covariates. Associations between postural balance testing conditions and Mn and Pb exposure were estimated with linear regression analyses adjusting for gender, age, parent IQ, and parent age. Mean blood Mn was 10 μg/L (SEM=0.36), mean blood Pb was 0.85 μg/dL (SEM=0.05), and mean hair Mn was 0.76 μg/g (SEM=0.16). Mean residential distance from the refinery was 11.5 km (SEM=0.46). All three measures of Mn exposure were significantly associated with poor postural balance. In addition, low-level blood Pb was also negatively associated with balance outcomes. We conclude that Mn exposure and low-level blood Pb are significantly associated with poor postural balance.

Trace elements and endometriosis: the ENDO study

There has been limited study of trace elements and endometriosis. Using a matched cohort design, 473 women aged 18-44 years were recruited into an operative cohort, along with 131 similarly aged women recruited into a population cohort. Endometriosis was defined as surgically visualized disease in the operative cohort, and magnetic resonance imaging diagnosed disease in the population cohort. Twenty trace elements in urine and three in blood were quantified using inductively coupled plasma mass spectrometry. Logistic regression estimated the adjusted odds (aOR) of endometriosis diagnosis for each element by cohort. No association was observed between any element and endometriosis in the population cohort. In the operative cohort, blood cadmium was associated with a reduced odds of diagnosis (aOR=0.55; 95% CI: 0.31, 0.98), while urinary chromium and copper reflected an increased odds (aOR=1.97; 95% CI: 1.21, 3.19; aOR=2.66; 95% CI: 1.26, 5.64, respectively). The varied associations underscore the need for continued research.

Assessment of prenatal mercury exposure in a predominately Caribbean immigrant community in Brooklyn, NY

Prenatal mercury exposure and its fetotoxic effects may be of particular concern in urban immigrant communities as a result of possible contributing cultural factors. The most common source of exposure in these communities is ingestion of fish and shellfish contaminated with methylmercury. Other sources of exposure may occur in ritualistic practices associated with Hispanic and Caribbean-based religions. This study 1) assessed total mercury levels in both random urine specimens from pregnant women, and in cord blood; and 2) examined environmental sources of exposure from a convenience sample in a predominantly Caribbean immigrant population in Brooklyn, New York. A questionnaire designed in collaboration with health professionals from the Caribbean community assessed the frequency of fish consumption, ritualistic practices, occupational exposures, and use of dental amalgams and mercury-containing skin and household products. The geometric mean for total mercury in cord blood was 2.14 μg L(-1) (95%CI: 1.76-2.60) (n = 78), and 0.45 μg L(-1) (95%CI: 0.37-0.55) (n = 183) in maternal urine corrected for creatinine (μg g(-1)). Sixteen percent of cord blood mercury levels exceeded the estimated equivalent of U.S. Environmental Protection Agency's Reference Dose (5.8 μg L(-1) blood). Predictors of cord blood mercury included maternal fish consumption and foreign birth of the mother. Predictors of urine mercury included foreign birth of the mother, number of dental amalgams, and special product use. There were no reports of mercury use in ritualistic practices or in cosmetics; however some women reported use of religious medals and charms. This study characterized risk factors for mercury exposure in a sample of urban, predominantly Caribbean-born blacks. Findings may help target interventions in this population, which might include appropriate fish selection and consumption frequency during pregnancy, and safe handling of mercury-containing products in the home.

Fish consumption, low-level mercury, lipids, and inflammatory markers in children

There is considerable evidence that consuming fish has numerous health benefits, including a reduced risk of cardiovascular disease. However, fish is also the primary source of human exposure to mercury (Hg). In a cross-sectional study of 9-11 year old children (N=100), we measured fish consumption, blood lipids, total blood Hg, diurnal salivary cortisol (4 samples collected throughout the day), and performed a proteomic analysis of serum proteins using spectral count shotgun proteomics. Children who consumed fish had a significantly more atheroprotective lipid profile but higher levels of blood Hg relative to children that did not consume fish. Although the levels of blood Hg were very low in these children (M=0.77 μg/L; all but 1 participant had levels below 3.27 μg/L), increasing blood Hg was significantly associated with blunted diurnal cortisol levels. Blood Hg was also significantly associated with acute-phase proteins suggesting systemic inflammation, and several of these proteins were found to significantly reduce the association between Hg and diminished cortisol when included in the model. This study of a pediatric population is the first to document an association between blood Hg, systemic inflammation, and endocrine disruption in humans. Without a better understanding of the long-term consequences of an atheroprotective lipid profile relative to blunted diurnal cortisol and systemic inflammation, a determination of the risk-benefit ratio for fish consumption by children is not possible.

Erratum: "A Biomonitoring Study of Lead, Cadmium, and Mercury in the Blood of New York City Adults"

[This corrects the article DOI: 10.1289/ehp.10056.].

Effects of lead and mercury on the blood proteome of children

Heavy metal exposure in children has been associated with a variety of physiological and neurological problems. The goal of this study was to utilize proteomics to enhance the understanding of biochemical interactions responsible for the health problems related to lead and mercury exposure at concentrations well below CDC guidelines. Blood plasma and serum samples from 34 children were depleted of their most abundant proteins using antibody-based affinity columns and analyzed using two different methods, LC-MS/MS and 2-D electrophoresis coupled with MALDI-TOF/MS and tandem mass spectrometry. Apolipoprotein E demonstrated an inverse significant association with lead concentrations (average being one microgram/deciliter) as deduced from LC-MS/MS and 2-D electrophoresis and confirmed by Western blot analysis. This coincides with prior findings that Apolipoprotein E genotype moderates neurobehavioral effects in individuals exposed to lead. Fifteen other proteins were identified by LC-MS/MS as proteins of interest exhibiting expressional differences in the presence of environmental lead and mercury.

Critical role of microglial CD40 in the maintenance of mechanical hypersensitivity in a murine model of neuropathic pain

We recently demonstrated a contributing role of spinal cord infiltrating CD4+ T lymphocytes in the maintenance of mechanical hypersensitivity in a rodent model of neuropathic pain, spinal nerve L5 transection (L5Tx). It has been demonstrated that microglia play a role in the etiology of pain states. We hypothesized that infiltrating CD4+ T lymphocytes communicate with microglia via a CD40-CD154 interaction. Here, we investigated the role of CD40 in the development of mechanical hypersensitivity post-L5Tx. CD40 KO mice displayed significantly decreased mechanical sensitivity compared with WT mice starting from day 5 post-L5Tx. Using bone marrow chimeric mice, we further identified a pro-nociceptive role of CNS microglial CD40 rather than the peripheral leukocytic CD40. Flow cytometric analysis determined a significant increase of CD40+ microglia in the ipsilateral side of lumbar spinal cord post-L5Tx. Further, spinal cord proinflammatory cytokine (IL-1beta, IL-6, IL-12, and TNF-alpha) profiling demonstrated an induction of IL-6 in both WT and CD40 KO mice post-L5Tx prior to the increase of microglial CD40 expression, indicating a CD40-independent induction of IL-6 following L5Tx. These data establish a novel role of microglial CD40 in the maintenance of nerve injury-induced behavioral hypersensitivity, a behavioral sign of neuropathic pain.

Suppression of tumour necrosis factor production from mononuclear cells by a novel synthetic compound, CLX-090717

OBJECTIVES

To evaluate the clinical efficacy of a novel synthetic peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonist, CLX-090717, in several in vitro cell culture systems and murine CIA, an experimental model of RA.

METHODS

Peripheral blood monocytes purified by elutriation, and rheumatoid synovial cells isolated from clinical tissue were cultured with CLX-090717 and TNF-alpha release was measured. Molecular mechanism of action was analysed by western blotting and electrophoretic mobility shift assay. Thioglycollate-elicited murine peritoneal macrophages were cultured with CLX-090717 and lipopolysaccharide (LPS)-induced TNF-alpha release was assayed. Therapeutic studies were done in mice with established arthritis by evaluating clinical parameters and histology. In addition, type II collagen response of lymphocytes from mice with CIA was examined.

RESULTS

CLX-090717 significantly inhibited spontaneous TNF-alpha release by RA synovial membrane cells, as well as LPS-induced TNF-alpha release from human and murine monocytic cells. Inhibition of TNF-alpha in monocytes was mediated partially through a nuclear factor-kappaB (NF-kappaB)-dependent pathway, as judged by sustained levels of IkappaBalpha in cytosolic extracts and a reduced level of LPS-induced NF-kappaB activity in nuclear extracts. CLX-090717 reduced clinical signs of arthritis and damage to joint architecture when administered therapeutically to arthritic mice. Mechanisms of action in CIA involved the reduction in proliferation of arthritic lymphocytes to antigen in vitro as well as reduced TNF-alpha release.

CONCLUSIONS

Our data suggest that the synthetic compound CLX-090717 has potential as a small molecular weight anti-inflammatory therapeutic for chronic inflammatory conditions.

A biomonitoring study of lead, cadmium, and mercury in the blood of New York city adults

OBJECTIVES

We assessed the extent of exposure to lead, cadmium, and mercury in the New York City (NYC) adult population.

METHODS

We measured blood metal concentrations in a representative sample of 1,811 NYC residents as part of the NYC Health and Nutrition Examination Survey, 2004.

RESULTS

The geometric mean blood mercury concentration was 2.73 microg/L [95% confidence interval (CI), 2.58-2.89]; blood lead concentration was 1.79 microg/dL (95% CI, 1.73-1.86); and blood cadmium concentration was 0.77 microg/L (95% CI, 0.75-0.80). Mercury levels were more than three times that of national levels. An estimated 24.8% (95% CI, 22.2-27.7%) of the NYC adult population had blood mercury concentration at or above the 5 microg/L New York State reportable level. Across racial/ethnic groups, the NYC Asian population, and the foreign-born Chinese in particular, had the highest concentrations of all three metals. Mercury levels were elevated 39% in the highest relative to the lowest income group (95% CI, 21-58%). Blood mercury concentrations in adults who reported consuming fish or shellfish 20 times or more in the last 30 days were 3.7 times the levels in those who reported no consumption (95% CI, 3.0-4.6); frequency of consumption explained some of the elevation in Asians and other subgroups.

CONCLUSIONS

Higher than national blood mercury exposure in NYC adults indicates a need to educate New Yorkers about how to choose fish and seafood to maximize health benefits while minimizing potential risks from exposure to mercury. Local biomonitoring can provide valuable information about environmental exposures.

Urban legend versus rural reality: patients' experience of attendance at accident and emergency departments in west Wales

OBJECTIVES

To investigate why and how patients decide to attend accident and emergency (A&E) departments, and to assess their satisfaction with the experience, in a predominantly rural west Wales population.

METHODS

This was a semi-structured follow up telephone interview of patients who walked in to A&E in one of four general hospitals in west Wales and were triaged as Manchester Triage score 4 or 5. Patients were recruited by nurses during the period July-November 2002. The study sample consisted of 176 male and 145 female patients, mean (SD) age 36.6 (20.0) years. The main outcome measure was a quantitative and qualitative description of the recalled experiences of A&E attenders, the circumstances of their attendance, and their satisfaction with the experience.

RESULTS

Of the study sample, 78% attended with injury or illnesses of recent origin, and 50% with actual or presumed musculoskeletal injury, 73% of which were sustained within 10 miles of home. Travel to hospital was by private transport for 86%, average distance 7.4 miles. The majority (90%) were registered with a local GP, but 32% felt A&E was the obvious choice, and a further 44% considered their GP inaccessible to their needs. Patients' reasons for seeking health care at A&E were similar to those described in an English urban study. Waiting times were rarely excessive; 80% left within 2 hours, and patient satisfaction was generally high. Among the 87 patients (27%) who reported a less satisfactory experience, 48 (55%) of these complained of dismissive attitudes of doctors.

CONCLUSIONS

Anecdotal accounts of abuse of A&E services and unreasonable patient expectations gain the status of "urban legends" within the medical profession. Among the predominantly settled rural population in west Wales, there is little evidence of unreasonable patient expectations, and most patients report high satisfaction levels. Patients' bad experiences most frequently arise from a dismissive attitude on the part of medical staff. These attitudes are often consequent on an A&E culture that views some patients' attendances as less appropriate than others.

Running economy is impaired following a single bout of resistance exercise

The purpose of this study was to determine whether a low-volume high-intensity resistance training session influenced running economy during a subsequent aerobic treadmill run. Nine well trained distance runners (mean +/- SD; VO2max, 66.6 +/- 10.2 ml x kg(-1) x min(-1); weight, 65.8 +/- 10.2 kg; height, 173.4 +/- 7.8 cm; age 20 +/- 1.1 years) with resistance training experience performed treadmill running at two different speeds (0.56 m x sec(-1) and 0.20 m x sec(-1) below speed corresponding to lactate equilibrium) either rested or 1, 8 or 24 hours after a 50-minute whole body resistance training session. Running economy was assessed using open circuit spirometry while heart rate was recorded telemetrically. The contractile properties of the quadriceps femoris were also determined following each resistance training session and prior to each treadmill run using percutaneous electrical stimulation. Submaximal oxygen consumption was significantly increased one hour (2.6 +/- 2.3%, p= 0.007), and eight hours (1.6 +/- 2.5%, p= 0.032), but not 24 hours after resistance training. No significant differences were found in exercising heart rate, ventilation, respiratory exchange ratio, ratings of perceived exertion, or running mechanics. Peak twitch torque, time to peak torque, and half relaxation time of the quadriceps femoris were significantly reduced immediately following resistance training while peak twitch torque was also lower one hour following resistance training. Running economy following a resistance training session is impaired for up to 8 hours. This change was not paralleled by a concomitant change in exercising heart rate. The mechanism responsible for increased oxygen consumption following resistance training may be related to impairment of the force generating capacity of skeletal muscle, as there was a significant decrement in the contractile properties of the quadriceps femoris following resistance training.

Identification of Residues Critical for Enzymatic Activity in the Domain Encoded by Exons 8 and 9 of the Human Inducible Nitric Oxide Synthase

Overproduction of nitric oxide (NO) by inducible NO synthase (iNOS) has been implicated in the pathogenesis of several diseases including airway inflammation of asthma. iNOS is active only as a homodimer. We previously demonstrated that the region encoded by exons 8 and 9 is critical for dimerization. In this study, alanine-scanning mutagenesis was used to identify critical amino acids in that region by expression of mutant proteins in human embryonic kidney 293 cells. All iNOS mutants yielded iNOS protein as detected by Western analysis. Four iNOS mutants with alanine replacing Trp260, Asn261, Tyr267, or Asp280 did not generate NO. Dimer formation was tested by sodium dodecyl sulfate polyacrylamide gel electrophoresis at 4 degrees C, followed by immunoblotting. Wild-type iNOS migrated both as monomers and dimers. iNOS mutants with alanine replacing Trp260, Asn261, or Tyr267, however, migrated only as monomers, suggesting that their inability to produce NO is related to a defect in dimer formation. Interestingly, the Asp280 mutant retained the ability to dimerize, indicating that it represents an inactive form of an iNOS dimer. These data identify four amino acids in exons 8 and 9 critical for iNOS activity, three of which also influence dimerization. These residues are strictly conserved among all NOS isforms and across species. Thus all NOS isoforms share general structural similarities, including specific amino acids critical for dimerization and catalytic activity. These data increase our understanding of the structural elements critical for NO synthesis and lay the groundwork for future studies aimed at downregulation of iNOS activity.

Use of diclofenac in children with asthma

This study investigated the effect of diclofenac on the lung function of 70 children aged 6-15 years with a diagnosis of asthma, recruited from a hospital respiratory clinic. Peak flow and a forced expiratory flow-volume loop were measured and the patients were then given 1-1.5 mg.kg-1 effervescent diclofenac orally. Spirometry was repeated at 10, 20 and 30 min, a 15% decrease in results being considered a significant reduction in lung function. No patient demonstrated a consistent reduction in lung function of > 15% during the study and there were no reports of wheezing or increased bronchodilator use after completion of the spirometry. In conclusion, we studied a group of genuine asthmatics and found no clinically significant incidence of bronchospasm with the use of a single therapeutic dose of diclofenac.

Anaesthetic management of a child with Burkitt's lymphoma of the larynx

An eight-year-old boy with a Burkitt's lymphoma of the upper airway is described. The use of sevoflurane for induction of anaesthesia in patients with airway obstruction is discussed. The logistical problems of upper airway surgery and anaesthesia in this type of patient are considered.

Cloning and characterization of human inducible nitric oxide synthase splice variants: a domain, encoded by exons 8 and 9, is critical for dimerization

The inducible nitric oxide synthase (iNOS) contains an amino-terminal oxygenase domain, a carboxy-terminal reductase domain, and an intervening calmodulin-binding region. For the synthesis of nitric oxide (NO), iNOS is active as a homodimer. The human iNOS mRNA is subject to alternative splicing, including deletion of exons 8 and 9 that encode amino acids 242-335 of the oxygenase domain. In this study, iNOS8(-)9(-) and full-length iNOS (iNOSFL) were cloned from bronchial epithelial cells. Expression of iNOS8(-)9(-) in 293 cell line resulted in generation of iNOS8(-)9(-) mRNA and protein but did not lead to NO production. In contrast to iNOSFL, iNOS8(-)9(-) did not form dimers. Similar to iNOSFL, iNOS8(-)9(-) exhibited NADPH-diaphorase activity and contained tightly bound calmodulin, indicating that the reductase and calmodulin-binding domains were functional. To identify sequences in exons 8 and 9 that are critical for dimerization, iNOSFL was used to construct 12 mutants, each with deletion of eight residues in the region encoded by exons 8 and 9. In addition, two "control" iNOS deletion mutants were synthesized, lacking either residues 45-52 of the oxygenase domain or residues 1131-1138 of the reductase domain. Whereas both control deletion mutants generated NO and formed dimers, none of the 12 other mutants formed dimers or generated NO. The region encoded by exons 8 and 9 is critical for iNOS dimer formation and NO production but not for reductase activity. This region could be a potential target for therapeutic interventions aimed at inhibiting iNOS dimerization and hence NO synthesis.

Reduced activity of tryptophan 2,3-dioxygenase in the liver of rats treated with chlorinated dibenzo-p-dioxins (CDDs): dose-responses and structure-activity relationship

The activity of tryptophan 2,3-dioxygenase (TdO) was measured in the livers of male Sprague-Dawley rats after acutely toxic doses (LD20-LD80) of chlorinated dibenzo-p-dioxins (CDDs) with 4 of the up to 7 chlorine substituents occupying the 2,3,7,8-positions. Treatment with toxic doses of CDDs results in voluntary feed refusal of rats. A corresponding involuntary reduction of feed intake in naive animals (pair-feeding) causes elevated levels of TdO activity. In the CDD treated rats, however, TdO activities were dose-dependently reduced. An LD80 reduced TdO activity to about 50% of the level found in the corresponding pair-fed animals. This decrease of TdO activity explains the dose-dependent increase of serum tryptophan, which in turn is the likely cause of voluntary feed refusal observed in CDD-treated rats. The activity of another enzyme which is regulated in a fashion very similar to that of TdO, viz., tyrosine aminotransferase (TAT), was consistently, but not dose-dependently, affected by treatment with CDDs.

Processes affecting the remediation of chromium-contaminated sites

The remediation of chromium-contaminated sites requires knowledge of the processes that control the migration and transformation of chromium. Advection, dispersion, and diffusion are physical processes affecting the rate at which contaminants can migrate in the subsurface. Heterogeneity is an important factor that affects the contribution of each of these mechanisms to the migration of chromium-laden waters. Redox reactions, chemical speciation, adsorption/desorption phenomena, and precipitation/dissolution reactions control the transformation and mobility of chromium. The reduction of CrVI to CrIII can occur in the presence of ferrous iron in solution or in mineral phases, reduced sulfur compounds, or soil organic matter. At neutral to alkaline pH, the CrIII precipitates as amorphous hydroxides or forms complexes with organic matter. CrIII is oxidized by manganese dioxide, a common mineral found in many soils. Solid-phase precipitates of hexavalent chromium such as barium chromate can serve either as sources or sinks for CrVI. Adsorption of CrVI in soils increases with decreasing chromium concentration, making it more difficult to remove the chromium as the concentration decreases during pump-and-treat remediation. Knowledge of these chemical and physical processes is important in developing and selecting effective, cost-efficient remediation designs for chromium-contaminated sites.

Sleep latency and lifestyle in Oxfordshire villages

Sleep latency, the usual delay in falling asleep, was estimated in 689 male and 757 female residents of a group of Oxfordshire villages by means of a sleep questionnaire. Sleep latency is analysed in relation to 59 descriptive elements of lifestyle and reported feelings. The pattern of association is broadly similar in the two sexes, and multivariate analysis identifies boredom and insufficient to do, mild morbidity, and use of sleeping tablets and tranquillizers as important correlates of long sleep latency in both sexes. These data are compared with a similar analysis of the correlates of sleep duration and sleep quality. It is concluded that sleep latency represents an important measure of well-being.

Urinary hormone levels: a population study of associations between steroid and catecholamine excretion rates

Urinary levels of steroid metabolites (17-hydroxycorticosteroids and 17-oxosteroids) were measured in 408 males at two times during the normal working day. Hormone levels are expressed both as rates of excretion and as creatinine ratios and are compared with the values for adrenaline and noradrenaline previously measured in the same samples. Strong associations are found between catecholamines and steroids. Generally the greatest correlation is with hormones of the same biochemical class, although the 17-hydroxycorticosteroid level is more strongly correlated with the adrenaline level than is the level of noradrenaline.