The effect domains, measures, and methods reported in pediatric-specialized multidisciplinary outpatient rehabilitation programs: An integrated review.

OBJECTIVES: Specialized pain rehabilitation is recognized as the treatment of choice for youth with pain-related disability. Appropriate outcomes for program evaluation are critical. This study aimed to summarize the effect domains and methods used to evaluate pediatric-specialized outpatient pain rehabilition programs, map them to the PedIMMPACT statement, and highlight future directions. METHODS: An integrated review framework, incorporating stakeholders, was used. Academic Search Complete, CINAHL, ERIC, MEDLINE, PsycINFO, and Google Scholar were searched for studies published in 1999-2021 featuring the treatment effects of specialized outpatient pain rehabilitation on youth with pain-related disability and their parents. Selected studies were critically appraised using the Quality Assessment Tool for Studies of Diverse Design, organized by study characteristics, and analyzed using constant comparison. RESULTS: From the 1951 potentially relevant titles, 37 studies were selected. Twenty-five effects targeted youth and 24 focused on parents, with a maximum of 15 youth and 11 parent effect domains (median = 5 domains per study). Although most studies measured a combination of effect domains and were inclusive of some recommended in the PedIMMPACT statement, no effect was measured consistently across studies. Youth physical functioning and parent emotional functioning were measured most often. Eighty-five instruments were used to assess youth outcomes and 59 for parents, with self-report questionnaires dominating. DISCUSSION: A lack of standardization exists associated with the domains and methods used to evaluate the effects of pediatric-specialized outpatient pain rehabilitation programs, hindering comparisons. Future program evaluations should be founded on their theory, aim, and anticipated outcomes.

LAMP: A CDC Program to Ensure the Quality of Blood-Lead Laboratory Measurements.

CONTEXT: The Lead and Multielement Proficiency (LAMP) program is an external quality assurance program promoting high-quality blood-lead measurements. OBJECTIVES: To investigate the ability of US laboratories, participating in the Centers for Disease Control and Prevention (CDC) LAMP program to accurately measure blood-lead levels (BLL) 0.70 to 47.5 µg/dL using evaluation criteria of ±2 µg/dL or 10%, whichever is greater. METHODS: The CDC distributes bovine blood specimens to participating laboratories 4 times per year. We evaluated participant performance over 5 challenges on samples with BLL between 0.70 and 47.5 µg/dL. The CDC sent 15 pooled samples (3 samples shipped in 5 rounds) to US laboratories. The LAMP laboratories used 3 primary technologies to analyze lead in blood: inductively coupled plasma mass spectrometry, graphite furnace atomic absorption spectroscopy, and LeadCare technologies based on anodic stripping voltammetry. Laboratories reported their BLL analytical results to the CDC. The LAMP uses these results to provide performance feedback to the laboratories. SETTING: The CDC sent blood samples to approximately 50 US laboratories for lead analysis. PARTICIPANTS: Of the approximately 200 laboratories enrolled in LAMP, 38 to 46 US laboratories provided data used in this report (January 2017 to March 2018). RESULTS: Laboratory precision ranged from 0.26 µg/dL for inductively coupled plasma mass spectrometry to 1.50 µg/dL for LeadCare instruments. All participating US LAMP laboratories reported accurate BLL for 89% of challenge samples, using the ±2 µg/dL or 10% evaluation criteria. CONCLUSIONS: Laboratories participating in the CDC's LAMP program can accurately measure blood lead using the current Clinical Laboratory Improvement Amendments of 1988 guidance of ±4 µg/dL or ±10%, with a success rate of 96%. However, when we apply limits of ±2 µg/dL or ±10%, the success rate drops to 89%. When challenged with samples that have target values between 3 and 5 µg/dL, nearly 100% of reported results fall within ±4 µg/dL, while 5% of the results fall outside of the acceptability criteria used by the CDC's LAMP program. As public health focuses on lower blood lead levels, laboratories must evaluate their ability to successfully meet these analytical challenges surrounding successfully measuring blood lead. In addition proposed CLIA guidelines (±2 µg/dL or 10%) would be achievable performance by a majority of US laboratories participating in the LAMP program.

Determination of Iodine Content in Dairy Products by Inductively Coupled Plasma Mass Spectrometry.

A probing study to establish a reliable and robust method for determining the iodine concentration using the ELAN® DRC™ II ICP-MS was performed in combination with a sample digestion and filtration step. Dairy products from locally available sources were evaluated to help determine the possibility and need for further evaluations in relation to the U.S. population's iodine intake. Prior to analysis, the samples were aliquoted and digested for 3 hours at 90±3 °C. Dilution and filtration were performed, following the digestion. The sample extract was analyzed, and the results were confirmed with NIST SRM 1549a Whole Milk Powder. Further experimentation will need to be performed to optimize the method for projected sample concentration and throughput.

Trace Metals Screening Process of Devices Used for the Collection, Analysis, and Storage of Biological Specimens.

The Centers for Disease Control and Prevention's (CDC) Environmental Health Laboratory uses modified versions of inductively coupled plasma mass spectrometry (ICP-MS) analytical methods to quantify metals contamination present in items that will come into contact with patient samples during the pre-analytical, analytical, and post-analytical stages. This lot screening process allows us to reduce the likelihood of introducing contamination which can lead to falsely elevated results. This is particularly important when looking at biomonitoring levels in humans which tend to be near the limit of detection of many methods. The fundamental requirements for a lot screening program in terms of facilities and processes are presented along with a discussion of sample preparation techniques used for lot screening. The criteria used to evaluate the lot screening data to determine the acceptability of a particular manufacturing lot is presented as well. As a result of lot testing, unsuitable manufactured lots are identified and excluded from use.

Thyroid antagonists and thyroid indicators in U.S. pregnant women in the Vanguard Study of the National Children's Study.

The sodium iodide-symporter (NIS) mediates uptake of iodide into thyroid follicular cells. This key step in thyroid hormone synthesis is inhibited by perchlorate, thiocyanate (SCN) and nitrate (NO3) anions. When these exposures occur during pregnancy the resulting decreases in thyroid hormones may adversely affect neurodevelopment of the human fetus. Our objectives were to describe and examine the relationship of these anions to the serum thyroid indicators, thyroid stimulating hormone (TSH) and free thyroxine (FT4), in third trimester women from the initial Vanguard Study of the National Children's Study (NCS); and to compare urine perchlorate results with those in pregnant women from the National Health and Nutritional Examination Survey (NHANES). Urinary perchlorate, SCN, NO3, and iodine, serum TSH, FT4, and cotinine were measured and a food frequency questionnaire (FFQ) was administered to pregnant women enrolled in the initial Vanguard Study. We used multiple regression models of FT4 and TSH that included perchlorate equivalent concentration (PEC, which estimates combined inhibitory effects of the anions perchlorate, SCN, and NO3 on the NIS). We used multiple regression to model predictors of each urinary anion, using FFQ results, drinking water source, season of year, smoking status, and demographic characteristics. Descriptive statistics were calculated for pregnant women in NHANES 2001-2012. The geometric mean (GM) for urinary perchlorate was 4.04µg/L, for TSH 1.46mIU/L, and the arithmetic mean for FT4 1.11ng/dL in 359 NCS women. In 330 women with completed FFQs, consumption of leafy greens, winter season, and Hispanic ethnicity were significant predictors of higher urinary perchlorate, which differed significantly by study site and primary drinking water source, and bottled water was associated with higher urinary perchlorate compared to filtered tap water. Leafy greens consumption was associated with higher urinary NO3 and higher urinary SCN. There was no association between urinary perchlorate or PEC and TSH or FT4, even for women with urinary iodine <100µg/L. GM urinary perchlorate concentrations in the full sample (n=494) of third trimester NCS women (4.03µg/L) were similar to pregnant women in NHANES (3.58µg/L).

Biomarkers of nutrition for development--iodine review.

The objective of the Biomarkers of Nutrition for Development (BOND) project is to provide state-of-the-art information and service with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect. Specifically, the BOND project seeks to develop consensus on accurate assessment methodologies that are applicable to researchers (laboratory/clinical/surveillance), clinicians, programmers, and policy makers (data consumers). The BOND project is also intended to develop targeted research agendas to support the discovery and development of biomarkers through improved understanding of nutrient biology within relevant biologic systems. In phase I of the BOND project, 6 nutrients (iodine, vitamin A, iron, zinc, folate, and vitamin B-12) were selected for their high public health importance because they typify the challenges faced by users in the selection, use, and interpretation of biomarkers. For each nutrient, an expert panel was constituted and charged with the development of a comprehensive review covering the respective nutrient's biology, existing biomarkers, and specific issues of use with particular reference to the needs of the individual user groups. In addition to the publication of these reviews, materials from each will be extracted to support the BOND interactive Web site (http://www.nichd.nih.gov/global_nutrition/programs/bond/pages/index.aspx). This review represents the first in the series of reviews and covers all relevant aspects of iodine biology and biomarkers. The article is organized to provide the reader with a full appreciation of iodine's background history as a public health issue, its biology, and an overview of available biomarkers and specific considerations for the use and interpretation of iodine biomarkers across a range of clinical and population-based uses. The review also includes a detailed research agenda to address priority gaps in our understanding of iodine biology and assessment.

Analytical method for total chromium and nickel in urine using an inductively coupled plasma-universal cell technology-mass spectrometer (ICP-UCT-MS) in kinetic energy discrimination (KED) mode.

Biomonitoring and emergency response measurements are an important aspect of the Division of Laboratory Sciences of the National Center for Environmental Health, Centers for Disease Control and Prevention (CDC). The continuing advancement in instrumentation allows for enhancements to existing analytical methods. Prior to this work, chromium and nickel were analyzed on a sector field inductively coupled plasma-mass spectrometer (SF-ICP-MS). This type of instrumentation provides the necessary sensitivity, selectivity, accuracy, and precision but due to the higher complexity of instrumentation and operation, it is not preferred for routine high throughput biomonitoring needs. Instead a quadrupole based method has been developed on a PerkinElmer NexION™ 300D ICP-MS. The instrument is operated using 6.0 mL min-1 helium as the collision cell gas and in kinetic energy discrimination mode, interferences are successfully removed for the analysis of 52Cr (40Ar12C and 35Cl16O1H) and 60Ni (44Ca16O). The limits of detection are 0.162 µg L-1 Cr and 0.248 µg L-1 Ni. Method accuracy using NIST SRM 2668 level 1 (1.08 µg L-1 Cr and 2.31µg L-1 Ni) and level 2 (27.7 µg L-1 Cr and 115 µg L-1 Ni) was within the 95% confidence intervals reported in the NIST certificate. Among-run precision is less than 10% RSDs (N = 20) for in house quality control and NIST SRM urine samples. While the limits of detection (LOD) for the new quadrupole ICP-UCT-MS with KED method are similar to the SF-ICP-MS method, better measurement precision is observed for the quadrupole method. The new method presented provides fast, accurate, and more precise results on a less complex and more robust ICP-MS platform.

Measurement of mercury species in human blood using triple spike isotope dilution with SPME-GC-ICP-DRC-MS.

The measurement of different mercury compounds in human blood can provide valuable information about the type of mercury exposure. To this end, our laboratory developed a biomonitoring method for the quantification of inorganic (iHg), methyl (MeHg), and ethyl (EtHg) mercury in whole blood using a triple-spike isotope dilution (TSID) quantification method employing capillary gas chromatography (GC) and inductively coupled dynamic reaction cell mass spectrometry (ICP-DRC-MS). We used a robotic CombiPAL(®) sample handling station featuring twin fiber-based solid-phase microextraction (SPME) injector heads. The use of two SPME fibers significantly reduces sample analysis cycle times making this method very suitable for high sample throughput, which is a requirement for large public health biomonitoring studies. Our sample preparation procedure involved solubilization of blood samples with tetramethylammonium hydroxide (TMAH) followed by the derivatization with sodium tetra(n-propyl)borate (NaBPr(4)) to promote volatility of mercury species. We thoroughly investigated mercury species stability in the blood matrix during the course of sample treatment and analysis. The method accuracy for quantifying iHg, MeHg, and EtHg was validated using NIST standard reference materials (SRM 955c level 3) and the Centre de Toxicologie du Québec (CTQ) proficiency testing (PT) samples. The limit of detection (LOD) for iHg, MeHg, and EtHg in human blood was determined to be 0.27, 0.12, and 0.16 µg/L, respectively.

Total and methyl mercury in whole blood measured for the first time in the U.S. population: NHANES 2011-2012.

BACKGROUND: Despite the public health and toxicologic interest in methyl mercury (MeHg) and ethyl mercury (EHg), these mercury species have been technically difficult to measure in large population studies. METHODS: Using NHANES 2011-2012 data, we calculated reference ranges and examined demographic factors associated with specific mercury species concentrations and the ratio of MeHg to THg. We conducted several multiple regression analyses to examine factors associated with MeHg concentrations and also with the ratio of MeHg to THg. RESULTS: Asians had the highest geometric mean concentrations for MeHg, 1.58 µg/L (95% CI 1.29, 1.93) and THg, 1.86 µg/L (1.58, 2.19), followed by non-Hispanic blacks with MeHg, 0.52 µg/L (0.39, 0.68) and THg, 0.68 µg/L (0.54, 0.85). Greater education attainment in adults and male sex were associated with higher MeHg and THg concentrations. Race/ethnicity, age, and sex were significant predictors of MeHg concentrations, which increased with age and were highest in Asians in all age categories, followed by non-Hispanic blacks. Mexican Americans had the lowest adjusted MeHg concentrations. The ratio of MeHg to THg was highest in Asians, varied by racial/ethnic group, and increased with age in a non-linear fashion. The amount of increase in the MeHg to THg ratio with age depended on the initial ratio, with a greater increase as age increased. Of the overall population, 3.05% (95% CI 1.77, 4.87) had MeHg concentrations >5.8 µg/L (a value that corresponds to the U.S. EPA reference dose). The prevalence was highest in Asians at 15.85% (95% CI 11.85, 20.56), increased with age, reaching a maximum of 9.26% (3.03, 20.42) at ages 60-69 years. Females 16-44 years old had a 1.76% (0.82-3.28) prevalence of MeHg concentrations >5.8 µg/L. CONCLUSIONS: Asians, males, older individuals, and adults with greater educational attainment had higher MeHg concentrations. The ratio of MeHg to THg varied with racial/ethnic group, increased with age, and was nonlinear. U.S. population reference values for MeHg and the ratio of MeHg to THg can assist in more precise assessment of public health risk from MeHg consumed in seafood.

Analysis of a novel field dilution method for testing samples that exceed the analytic range of point-of-care blood lead analyzers.

Investigators developed and evaluated a dilution method for the LeadCare II analyzer (LCII) for blood lead levels >65 µg/dL, the analyzer's maximum reporting value. Venous blood samples from lead-poisoned children were initially analyzed in the field using the dilution method. Split samples were analyzed at the US Centers for Disease Control and Prevention (CDC) laboratory using both the dilution method and inductively coupled plasma-mass spectrometry (ICP-MS). The concordance correlation coefficient of CDC LCII vs. ICP-MS values (N = 211) was 0.976 (95 % confidence interval (CI) 0.970-0.981); of Field LCII vs. ICP-MS (N = 68) was 0.910 (95% CI 0.861-0.942), and CDC LCII vs. Field LCII (N = 53) was 0.721 (95% CI 0.565-0.827). Sixty percent of CDC and 54% of Field LCII values were within ±10% of the ICP-MS value. Results from the dilution method approximated ICP-MS values and were useful for field-based decision-making. Specific recommendations for additional evaluation are provided.

The impact of succimer chelation on blood cadmium in children with background exposures: a randomized trial.

Succimer lowers blood lead concentrations in children, and the structure of succimer chelates of lead and cadmium are similar. Using blood samples from a randomized trial of succimer for lead poisoning, however, we found that succimer did not lower blood cadmium in children with background exposure.

Race-ethnicity is related to biomarkers of iron and iodine status after adjusting for sociodemographic and lifestyle variables in NHANES 2003-2006.

The NHANES 2003-2006 has assessed iron and iodine status, 2 trace element nutrients of continued public health interest, in the U.S. population. We investigated associations of sociodemographic (age, sex, race-ethnicity, education, income) and lifestyle (smoking, alcohol consumption, BMI, physical activity, dietary supplement use) variables with the iron status indicators serum ferritin, soluble transferrin receptor (sTfR), and body iron in women aged 20-49 y (n = 2539, 2513, and 2509, respectively) and with urine iodine, a biomarker of iodine intake, in adults aged ≥ 20 y (n = 3066). Significant correlations between the study variables and biomarkers were weak (|r| ≤ 0.24). Urine creatinine (uCr) was moderately significantly correlated with urine iodine (r = 0.52). The individual variables explained ≤ 5% of the variability in biomarker concentrations in bivariate analysis. In multiple regression models, sociodemographic and lifestyle variables together explained 4-13% of the variability in iron indicators and 41% of the variability in urine iodine (uCr in the model). The adjusted estimated body iron was ≈ 1 unit (mg/kg) lower in non-Hispanic black vs. non-Hispanic white women and ≈ 1 unit higher in women who smoked vs. those who did not and in women consuming 1 vs. 0 alcoholic drinks/d. The adjusted estimated urine iodine concentration (uCr in the model) was 34% lower in non-Hispanic blacks vs. non-Hispanic whites, 22% higher in supplement users vs. nonusers, and 11% higher with every 10-y increase in age. In summary, after adjusting for sociodemographic and lifestyle variables (and uCr in the iodine model), race-ethnicity retained a strong association with sTfR, body iron, and urine iodine; smoking and alcohol consumption with iron biomarkers; and supplement use and age with urine iodine.

Intakes of dairy products and dietary supplements are positively associated with iodine status among U.S. children.

Although pregnant women and some groups of reproductive-age women in the US may be at risk of iodine deficiency, data also suggest that iodine intake among many U.S. children may be above requirements. Our objective was to describe the association of iodine sources with iodine status among children. We analyzed 2007-2010 NHANES data of urine iodine concentration (UIC) spot tests for children aged 6-12 y (n = 1553) and used WHO criteria for iodine status (median UIC: 100-199 µg/L = adequate; 200-299 µg/L = above requirements; ≥300 µg/L = excess). The overall median UIC was above requirements for children aged 6-12 y [211 µg/L (95% CI: 194, 228 µg/L)]. Median UIC increased by quartile of previous day dairy intake, ranging from adequate in the lowest quartile [157 µg/L (95% CI: 141, 170 µg/L)] to above requirements in the highest quartile [278 µg/L (95% CI: 252, 336 µg/L)]. Median UIC was 303 µg/L (95% CI: 238, 345 µg/L) among the 17% of children who had taken a dietary supplement containing iodine the previous day, compared with 198 µg/L (95% CI: 182, 214 µg/L) among those who had not. In adjusted regression analyses, recent dairy intake and recent supplement use were significantly positively associated with UIC levels, whereas recent grain intake was negatively associated. Adding salt to food at the table was not associated with UIC. Iodine-containing supplements are likely not needed by most schoolchildren in the US because dietary iodine intake is adequate in this age group.

Urinary excretion of sodium, potassium, and chloride, but not iodine, varies by timing of collection in a 24-hour calibration study.

Because of the logistic complexity, excessive respondent burden, and high cost of conducting 24-h urine collections in a national survey, alternative strategies to monitor sodium intake at the population level need to be evaluated. We conducted a calibration study to assess the ability to characterize sodium intake from timed-spot urine samples calibrated to a 24-h urine collection. In this report, we described the overall design and basic results of the study. Adults aged 18-39 y were recruited to collect urine for a 24-h period, placing each void in a separate container. Four timed-spot specimens (morning, afternoon, evening, and overnight) and the 24-h collection were analyzed for sodium, potassium, chloride, creatinine, and iodine. Of 481 eligible persons, 407 (54% female, 48% black) completed a 24-h urine collection. A subsample (n = 133) collected a second 24-h urine 4-11 d later. Mean sodium excretion was 3.54 ± 1.51 g/d for males and 3.09 ± 1.26 g/d for females. Sensitivity analysis excluding those who did not meet the expected creatinine excretion criterion showed the same results. Day-to-day variability for sodium, potassium, chloride, and iodine was observed among those collecting two 24-h urine samples (CV = 16-29% for 24-h urine samples and 21-41% for timed-spot specimens). Among all race-gender groups, overnight specimens had larger volumes (P < 0.01) and lower sodium (P < 0.01 to P = 0.26), potassium (P < 0.01), and chloride (P < 0.01) concentrations compared with other timed-spot urine samples, although the differences were not always significant. Urine creatinine and iodine concentrations did not differ by the timing of collection. The observed day-to-day and diurnal variations in sodium excretion illustrate the importance of accounting for these factors when developing calibration equations from this study.

Changes in the concentrations of biochemical indicators of diet and nutritional status of pregnant women across pregnancy trimesters in Trujillo, Peru, 2004-2005.

BACKGROUND: In developing countries, deficiencies in essential micronutrients are common, particularly in pregnant women. Although, biochemical indicators of diet and nutrition are useful to assess nutritional status, few studies have examined such indicators throughout pregnancy in women in developing countries. METHODS: The primary objective of this study was to assess the nutritional status of 78 Peruvian women throughout pregnancy for 16 different nutritional indicators including fat-soluble vitamins and carotenoids, iron-status indicators, and selenium. Venous blood samples from which serum was prepared were collected during trimesters one (n = 78), two (n = 65), three (n = 62), and at term via the umbilical cord (n = 52). Questionnaires were completed to determine the demographic characteristics of subjects. Linear mixed effects models were used to study the associations between each maternal indicator and the demographic characteristics. RESULTS: None of the women were vitamin A and E deficient at any stage of pregnancy and only 1/62 women (1.6%) was selenium deficient during the third trimester. However, 6.4%, 44% and 64% of women had ferritin levels indicative of iron deficiency during the first, second and third trimester, respectively. Statistically significant changes (p ≤ 0.05) throughout pregnancy were noted for 15/16 nutritional indicators for this Peruvian cohort, with little-to-no association with demographic characteristics. Three carotenoids (beta-carotene, beta-cryptoxanthin and trans-lycopene) were significantly associated with education status, while trans-lycopene was associated with age and beta-cryptoxanthin with SES (p < 0.05). Concentrations of retinol, tocopherol, beta-cryptoxanthin, lutein + zeaxanthin and selenium were lower in cord serum compared with maternal serum (p < 0.05). Conversely, levels of iron status indicators (ferritin, transferrin saturation and iron) were higher in cord serum (p < 0.05). CONCLUSION: The increasing prevalence of iron deficiency throughout pregnancy in these Peruvian women was expected. It was surprising though not to find deficiencies in other nutrients. The results highlight the importance of continual monitoring of women throughout pregnancy for iron deficiency which could be caused by increasing fetal needs and/or inadequate iron intake as pregnancy progresses.

Summary of an NIH workshop to identify research needs to improve the monitoring of iodine status in the United States and to inform the DRI.

The Office of Dietary Supplements (ODS) at the NIH sponsored a workshop on May 12-13, 2011, to bring together representatives from various NIH institutes and centers as a first step in developing an NIH iodine research initiative. The workshop also provided an opportunity to identify research needs that would inform the dietary reference intakes for iodine, which were last revised in 2001. Iodine is required throughout the life cycle, but pregnant women and infants are the populations most at risk of deficiency, because iodine is required for normal brain development and growth. The CDC monitors iodine status of the population on a regular basis, but the status of the most vulnerable populations remains uncertain. The NIH funds very little investigator-initiated research relevant to iodine and human nutrition, but the ODS has worked for several years with a number of other U.S. government agencies to develop many of the resources needed to conduct iodine research of high quality (e.g., validated analytical methods and reference materials for multiple types of samples). Iodine experts, scientists from several U.S. government agencies, and NIH representatives met for 2 d to identify iodine research needs appropriate to the NIH mission.

Efficacy of succimer chelation of mercury at background exposures in toddlers: a randomized trial.

OBJECTIVE: To examine whether succimer, a mercaptan compound known to reduce blood lead concentration in children, reduces blood mercury concentration. STUDY DESIGN: We used samples from a randomized clinical trial of succimer chelation for lead-exposed children. We measured mercury levels in pre-treatment samples from 767 children. We also measured mercury levels in blood samples drawn 1 week after treatment began (n = 768) and in a 20% random sample of the children who received the maximum 3 courses of treatment (n = 67). A bootstrap-based isotonic regression method was used to compare the trend with time in the difference between the adjusted mean mercury concentrations in the succimer group and that in the placebo group. RESULTS: The adjusted mean organic mercury concentration in the succimer group relative to the placebo group fell from 99% at baseline to 82% after 3 courses of treatment (P for trend = .048), but this resulted from the prevention of the age-related increase in the succimer group. CONCLUSION: Succimer chelation for low level organic mercury exposure in children has limited efficacy.

Body burdens of mercury, lead, selenium and copper among Baltimore newborns.

Umbilical cord blood or serum concentrations of mercury, lead, selenium and copper were measured with inductively coupled plasma mass spectrometry in a population of 300 infants born in Baltimore, Maryland. Geometric mean values were 1.37 µg/L (95% confidence interval: 1.27, 1.48) for mercury; 0.66 µg/dL (95% CI: 0.61, 0.71) for lead; and 38.62 µg/dL (95% CI: 36.73, 40.61) for copper. Mean selenium was 70.10 µg/L (95% CI: 68.69, 70.52). Mercury, selenium and copper levels were within exposure ranges reported among similar populations, whereas the distribution of lead levels was lower than prior reports; only one infant had a cord blood lead above 10 µg/dL. Levels of selenium were significantly correlated with concentrations of lead (Spearman's ρ=0.20) and copper (Spearman's ρ=0.51). Multivariable analyses identified a number of factors associated with one of more of these exposures. These included: increase in maternal age (increased lead); Asian mothers (increased mercury and lead, decreased selenium and copper); higher umbilical cord serum n-3 fatty acids (increased mercury, selenium and copper), mothers using Medicaid (increased lead); increasing gestational age (increased copper); increasing birthweight (increased selenium); older neighborhood housing stock (increased lead and selenium); and maternal smoking (increased lead). This work provides additional information about contemporary prenatal element exposures and can help identify groups at risk of atypical exposures.

Whole blood lead levels are associated with biomarkers of joint tissue metabolism in African American and white men and women: the Johnston County Osteoarthritis Project.

PURPOSE: To examine associations between biomarkers of joint tissue metabolism and whole blood lead (Pb), separately for men and women in an African American and Caucasian population, which may reflect an underlying pathology. METHODS: Participants in the Johnston County Osteoarthritis Project Metals Exposure Sub-Study (329 men and 342 women) underwent assessment of whole blood Pb and biochemical biomarkers of joint tissue metabolism. Urinary cross-linked N telopeptide of type I collagen (uNTX-I) and C-telopeptide fragments of type II collagen (uCTX-II), serum cleavage neoepitope of type II collagen (C2C), serum type II procollagen synthesis C-propeptide (CPII), and serum hyaluronic acid (HA) were measured using commercially available kits; the ratio of [C2C:CPII] was calculated. Serum cartilage oligomeric matrix protein (COMP) was measured by an in-house assay. Multiple linear regression models were used to examine associations between continuous blood Pb and biomarker outcomes, adjusted for age, race, current smoking status, and body mass index. Results are reported as estimated change in biomarker level for a 5-unit change in Pb level. RESULTS: The median Pb level among men and women was 2.2 and 1.9µg/dL, respectively. Correlations were noted between Pb levels and the biomarkers uNTX-I, uCTX-II, and COMP in women, and between Pb and uCTX-II, COMP, CPII, and the ratio [C2C:CPII] in men. In adjusted models among women, a 5-unit increase in blood Pb level was associated with a 28% increase in uCTX-II and a 45% increase in uNTX-I levels (uCTX-II: 1.28 [95% CI: 1.04-1.58], uNTX-I: 1.45 [95% CI:1.21-1.74]). Among men, levels of Pb and COMP showed a borderline positive association (8% increase in COMP for a 5-unit change in Pb: 1.08 [95% CI: 1.00-1.18]); no other associations were significant after adjustment. CONCLUSIONS: Based upon known biomarker origins, the novel associations between blood Pb and biomarkers appear to be primarily reflective of relationships to bone and calcified cartilage turnover among women and cartilage metabolism among men, suggesting a potential gender-specific effect of Pb on joint tissue metabolism that may be relevant to osteoarthritis.

Determination of seven arsenic compounds in urine by HPLC-ICP-DRC-MS: a CDC population biomonitoring method.

A robust analytical method has been developed and validated by use of high-performance liquid chromatography inductively coupled plasma mass spectrometry with Dynamic Reaction Cell (DRC) technology that separates seven arsenic (As) species in human urine: arsenobetaine (AB), arsenocholine, trimethylarsine oxide (TMAO), arsenate (As(V)), arsenite (As(III)), monomethylarsonate, and dimethylarsinate. A polymeric anion-exchange (Hamilton PRP X-100) column was used for separation of the species that were detected at m/z 75 by ICP-DRC-MS (PerkinElmer SCIEX ELAN DRCII) using 10% hydrogen-90% argon as the DRC gas. The internal standard (As) is added postcolumn via an external injector with a sample loop. All analyte peaks were baseline-separated except AB and TMAO. Analytical method limits of detection for the various species ranged from 0.4 to 1.7 microg L(-1) as elemental As. As(III) conversion to As(V) was avoided by adjusting the urine sample to