Blood lead level association with lower body weight in NHANES 1999-2006

BACKGROUND Lead exposure is associated with low birth-weight. The objective of this study is to determine whether lead exposure is associated with lower body weight in children, adolescents and adults. METHODS We analyzed data from NHANES 1999-2006 for participants aged ≥3 using multiple logistic and multivariate linear regression. Using age- and sex-standardized BMI Z-scores, overweight and obese children (ages 3-19) were classified by BMI ≥85 th and ≥95 th percentiles, respectively. The adult population (age ≥20) was classified as overweight and obese with BMI measures of 25-29.9 and ≥30, respectively. Blood lead level (BLL) was categorized by weighted quartiles. RESULTS Multivariate linear regressions revealed a lower BMI Z-score in children and adolescents when the highest lead quartile was compared to the lowest lead quartile (β (SE)=-0.33 (0.07), p<0.001), and a decreased BMI in adults (β (SE)=-2.58 (0.25), p<0.001). Multiple logistic analyses in children and adolescents found a negative association between BLL and the percentage of obese and overweight with BLL in the highest quartile compared to the lowest quartile (OR=0.42, 95% CI: 0.30-0.59; and OR=0.67, 95% CI: 0.52-0.88, respectively). Adults in the highest lead quartile were less likely to be obese (OR=0.42, 95% CI: 0.35-0.50) compared to those in the lowest lead quartile. Further analyses with blood lead as restricted cubic splines, confirmed the dose-relationship between blood lead and body weight outcomes. CONCLUSIONS BLLs are associated with lower body mass index and obesity in children, adolescents and adults.

A comparison between the chemical behaviour of lead-gold and lead-bismuth eutectics towards 316L stainless steel

Lead-gold eutectic (LGE) has been recently proposed as an alternative target material for high power spallation sources. In order to compare the corrosive properties of LGE to the better-studied eutectic of lead-bismuth (LBE), an isothermal twin-loop made of SS 316L was built and operated at the Institute of Physics of the University of Latvia. We have measured the concentration of steel alloying elements dissolved in both alloys at the end of two test campaigns via ICP-OES. In case of LGE, a pronounced concentration increase of Fe, Ni, Mn and Cr is found in the liquid metal, which is significantly higher compared to LBE. Similar results were obtained during complementary investigations on material samples exposed to both alloys in this twin-loop at 400 ◦C and 450 ◦C. These findings indicate that in contact with LGE, SS 316L steel suffers from substantial chemical attack. Detailed investigations using structure materials other than SS 316L have to be undertaken before qualifying LGE as a serious alternative to LBE.

An optimized lead system for long-term esophageal electrocardiography

Long-term electrocardiography (ECG) featuring adequate atrial and ventricular signal quality is highly desirable. Routinely used surface leads are limited in atrial signal sensitivity and recording capability impeding complete ECG delineation, i.e. in the presence of supraventricular arrhythmias. Long-term esophageal ECG might overcome these limitations but requires a dedicated lead system and recorder design. To this end, we analysed multiple-lead esophageal ECGs with respect to signal quality by describing the ECG waves as a function of the insertion level, interelectrode distance, electrode shape and amplifier's input range. The results derived from clinical data show that two bipolar esophageal leads, an atrial lead with short (15 mm) interelectrode distance and a ventricular lead with long (80 mm) interelectrode distance provide non-inferior ventricular signal strength and superior atrial signal strength compared to standard surface lead II. High atrial signal slope in particular is observed with the atrial esophageal lead. The proposed esophageal lead system in combination with an increased recorder input range of ±20 mV minimizes signal loss due to excessive electrode motion typically observed in esophageal ECGs. The design proposal might help to standardize long-term esophageal ECG registrations and facilitate novel ECG classification systems based on the independent detection of ventricular and atrial electrical activity.

Does ‘better’ discounting lead to ‘worse’ outcomes in long-run decisions? The dilemma of hyperbolic discounting

The shortcomings of conventional discounting, especially in the context of long-run environmental problems, have been extensively discussed in the literature. Recently, hyperbolic discounting, i. e. discounting at declining instead of constant discount rates, has attracted a lot of interest among both scientists and politicians. Although there are compelling arguments for employing hyperbolic discounting, there are also pitfalls, which have to be pointed out. In this paper I show that the problem of time-inconsistency, an inherent characteristics of hyperbolic discounting, leads to a potential clash between economic efficiency and intergenerational equity. As an example, I refer to the weak progress in the controlling of greenhouse gas emissions under the Kyoto protocol. As the problem of time-inconsistency cannot be solved on economic grounds alone, there is a need for an intergenerational moral commitment.

A process evaluation of the childhood lead poisoning prevention program in Houston, Texas, 1992--1995

A process evaluation of the Houston Childhood Lead Poisoning Prevention Program, 1992-1995, was conducted. The Program's goal is to reduce lead poisoning prevalence. The study proposed to determine to what extent the Program was implemented as planned by measuring how well Program services were actually: (1) received by the intended target population; (2) delivered to children with elevated blood lead levels; (3) delivered in compliance with the Centers for Disease Control and Prevention and Program guidelines and timetables; and (4) able to reduce lead poisoning prevalence among those rescreened. Utilizing a program monitoring design, the Program's pre-collected computer records were reviewed. The study sample consisted of 820 children whose blood lead levels were above 15 micrograms per deciLiter, representing approximately 2.9% of the 28,406 screened over this period. Three blood lead levels from each participant were examined: the initial elevated result; the confirmatory result; and the next rescreen result, after the elevated confirmatory level. Results showed that the Program screened approximately 18% (28,406 of 161,569) of Houston's children under age 6 years for lead poisoning. Based on Chi-square tests of significance, results also showed that lead-poisoned participants were more likely to be younger than 3 years, male and Hispanic, compared to those not lead poisoned. The age, gender and ethnic differences observed were statistically significant (p =.01, p =.00, p =.00). Four of the six Program services: medical evaluations, rescreening, environmental inspections and confirmation, had satisfactory delivery completion rates of 71%-98%. Delivery timetable compliance rates for three of the six services examined: outreach contacts, home visits and environmental inspections were below 32%. However, dangerously elevated blood lead levels fell and lead poisoning prevalence dropped from 3.3% at initial screening to 1.2% among those rescreened, after intervention. From a public health perspective, reductions in lead poisoning prevalence are very meaningful. Based on these findings, the following are recommendations for future research: (1) integrate Program database files by utilizing a computer database management program; (2) target services at Hispanic male children under age 3 years living in the highest risk neighborhoods; (3) increase resources to: improve tracking and documentation of service delivery and provide more non-medical case management and environmental services; and (4) share the evaluation methodology/findings with the Centers for Disease Control and Prevention administrators; the implications may be relevant to other program managers conducting such assessments. ^

Ice Core Record of Rising Lead Pollution in the North Pacific Atmosphere

A high-resolution, 8000 year-long ice core record from the Mt. Logan summit plateau (5300 m asl) reveals the initiation of trans-Pacific lead (Pb) pollution by ca. 1730, and a > 10-fold increase in Pb concentration (1981-1998 mean = 68.9 ng/l) above natural background (5.6 ng/l) attributed to rising anthropogenic Pb emissions from Asia. The largest rise in North Pacific Pb pollution from 1970-1998 (end of record) is contemporaneous with a decrease in Eurasian and North American Pb pollution as documented in ice core records from Greenland, Devon Island, and the European Alps. The distinct Pb pollution history in the North Pacific is interpreted to result from the later industrialization and less stringent abatement measures in Asia compared to North America and Eurasia. The Mt. Logan record shows evidence for both a rising Pb emissions signal from Asia and a trans-Pacific transport efficiency signal related to the strength of the Aleutian Low.

Efficacy of lead-in silibinin and subsequent triple therapy in difficult-to-treat HIV/hepatitis C virus-coinfected patients

OBJECTIVES: The efficacy of current hepatitis C virus (HCV) triple therapy, including a protease inhibitor, is limited in HIV/HCV-coinfected patients with advanced liver fibrosis and nonresponse to previous peginterferon-ribavirin. These patients have a low chance (only 30%) of achieving a sustained virological response (SVR) during triple therapy and cannot wait for next-generation anti-HCV drugs. In a pilot study, we investigated the efficacy of a lead-in therapy with silibinin before triple therapy in difficult-to-treat patients. METHODS: Inclusion criteria were HIV/HCV coinfection with advanced liver fibrosis and documented failure of previous peginterferon-ribavirin treatment. Intervention was lead-in therapy with intravenous silibinin 20 mg/kg/day for 14 days. Subsequently, peginterferon-ribavirin combined with telaprevir was initiated for 12 weeks, followed by peginterferon-ribavirin dual therapy until week 48 after initiation of triple therapy. The outcome measurements were HCV RNA after silibinin lead-in, at weeks 2, 4 and 12 of triple therapy, and SVR at week 24 after the end of treatment. RESULTS: We examined six HIV/HCV-coinfected patients (four infected with genotype 1a). All had fibrosis grade METAVIR ≥F3 and were on fully suppressive antiretroviral therapy. Mean HCV RNA decline after silibinin therapy was 2.6 log10 IU/mL (range 2-3 log10 IU/mL). Five of the six patients were virologically suppressed at weeks 2 and 4, and all six at week 12 of triple therapy. One experienced a viral breakthrough thereafter. Four of five patients (80%) showed an SVR 24. One patient had an SVR 12 but has not yet reached week 24. CONCLUSIONS: A lead-in with silibinin before triple therapy is highly effective and increases the probability of HCV treatment success in difficult-to-treat HIV/HCV-coinfected patients with advanced liver fibrosis and previous failure of peginterferon-ribavirin.

The Yanque prospect (Peru): from polymetallic Zn-Pb mineralization to a nonsulfide deposit

The Yanque nonsulfide Pb-Zn deposit (inferred resources 12.5 Mt @ 3.7% Pb and @ 3.5% Zn) is located in the Andahuaylas-Yauri ore province (Cuzco, southern Peru). The deposit occurs within a base metal mineralized district, centered on the medium-sized Dolores porphyry copper. A thorough geological, mineralogical and geochemical study has carried out in order to define: the relationships between the Dolores Cu-porphyry ore and the Yanque Zn-Pb polymetallic mineralization, and the characteristics of the economic nonsulfide concentrations. Both sedimentary and igneous rocks constitute the backbone of the Yanque-Dolores area. The sedimentary lithologies belong to the Soraya, Mara and Ferrobamba Fms. (upper Jurassic-middle Cretaceous). The Yanque orebody is hosted by the Mara Fm., which prevailingly consists of a siliciclastic sedimentary breccia. The original sulfide mineralization consisted of galena, pyrite and sphalerite. The host rock has been affected by a strong hydrothermal alteration, characterized by prevailing sericite/illite, as in the typical porphyry-related phyllic-argillic alteration stage, and by minor kaolinite, dolomite and quartz. Minor element geochemistry, characterized by Sb, As, Mn, Ag and locally also by Cu, points to magmatic-hydrothermal related mineralizing fluids. The Pb isotopic compositions from Dolores and Yanque sulfides are similar, and are typical of the Tertiary magmatically-derived ores in this part of Peru. The hydrothermally altered rocks at Yanque have the same Pb isotopic compositions as the sulfides, thus confirming the hypothesis that the Yanque primary Zn-Pb mineralization may have been produced by hydrothermal circulation related to the emplacement of the Dolores Cu-porphyry, as it is the case of other porphyry Cu systems associated with polymetallic mineralization elsewhere. However, no simple genetic model for the mineralization involving just one fluid circulation episode is able to explain the data. The Yanque economic nonsulfide ore association consists of sauconite, hemimorphite, smithsonite and cerussite, which result from the weathering and alteration of the original sulfide mineralization. Zinc is allocated mainly in sauconite (Zn-smectite), rather than in carbonates: a factor strictly related to the prevailing siliciclastic character of the host rock. Distinctive features of the Yanque orebody are the comparable ore grades for both Pb and Zn (3.5% Zn and 3.7% Pb), and the inverse supergene chemical zoning. In fact, contrary to other supergene ores of this type, zinc prevails in the top zone of the Yanque deposit, whereas lead content increases with depth. Considering the different mobility of the two metals in solution, it may be assumed that most of the primary zinc that was the source for the Yanque nonsulfides was originally located far from the position occupied by the galena mineralization, whose remnants have been observed on site. Zinc sulfides may have been originally contained in the eroded rock volumes that surrounded the actual deposit: the zinc-rich solutions have possibly migrated through the siliciclastic Mara Fm. and precipitated the nonsulfide minerals by porosity filling and replacement processes. In this sense, the Yanque secondary Zn-Pb deposit could be considered as a special type of “Exotic” mineralization.

Elemental and Lead Isotopic Data of Copper Finds from the Singen Cemetery, Germany – a Methodological Approach to Investigate Early Bronze Age Trade Networks

We report a trace element - Pb isotope analytical (LIA) database on the "Singen Copper", a peculiar type of copper found in the North Alpine realm, from its type locality, the Early Bronze Age Singen Cemetery (Germany). What distinguishes “Singen Copper” from other coeval copper types? (i) is it a discrete metal lot with a uniform provenance (if so, can its provenance be constrained)? (ii) was it manufactured by a special, unique metallurgical process that can be discriminated from others? Trace element concentrations can give clues on the ore types that were mined, but they can be modified (more or less intentionally) by metallurgical operations. A more robust indicator are the ratios of chemically similar elements (e.g. Co/Ni, Bi/Sb, etc.), since they should remain nearly constant during metallurgical operations, and are expected to behave homogeneously in each mineral of a given mining area, but their partition amongst the different mineral species is known to cause strong inter-element fractionations. We tested the trace element ratio pattern predicted by geochemical arguments on the Brixlegg mining area. Brixlegg itself is not compatible with the Singen Copper objects, and we only report it because it is a rare instance of a mining area for which sufficient trace element analyses are available in the literature. We observe that As/Sb in fahlerz varies by a factor 1.8 above/below median; As/Sb in enargite varies by a factor of 2.5 with a 10 times higher median. Most of the 102 analyzed metal objects from Singen are Sb-Ni-rich, corresponding to “antimony-nickel copper” of the literature. Other trace element concentrations vary by > 100 times, ratios by factors > 50. Pb isotopic compositions are all significantly different from each other. They do not form a single linear array and require > 3 ore batches that certainly do not derive from one single mining area. Our data suggest a heterogeneous provenance of “Singen copper”. Archaeological information limits the scope to Central European sources. LIA requires a diverse supply network from many mining localities, including possibly Brittany. Trace element ratios show more heterogeneity than LIA; this can be explained either by deliberate selection of one particular ore mineral (from very many sources) or by processing of assorted ore minerals from a smaller number of sources, with the unintentional effect that the quality of the copper would not be constant, as the metallurgical properties of alloys would vary with trace element concentrations.