Elevated blood lead concentrations and vitamin D deficiency in winter and summer in young urban children

Toxic Metals and Non-Communicable Diseases in HIV Population: A Systematic Review

Background and Objectives: HIV has been a serious global health concern since its discovery, with about 37.9 million people living with HIV worldwide as of 2018. Sub-Saharan Africa (SSA) accounts for 68% of the infection and contributed 74% of the 1.5 million deaths in 2013 despite having only 12% of the total world population residing in the region. This systematic review has attempted to determine the association between heavy metal toxicity and the occurrence of non-communicable diseases in the HIV/AIDS population. Materials and Methods: Three databases were systematically searched: PubMed, Scopus, and Google Scholar for studies written in English and published between 1 April 2000 and 12 April 2020. Studies were excluded if the main outcomes were not measured or did not meet the inclusion criteria. Results: All the six included studies are cross-sectional in design, and therefore were evaluated using the STROBE checklist. The data extraction was done using an extraction table; the ratio of female to male participants included in the study was 1.09:1. Qualitative analysis was used due to the heterogeneity in the heavy metal biomarkers and the outcome measured by the included studies. Two studies compared the concentration of heavy metals in HIV-positive and HIV-negative participants while one compared the levels between HAART-naïve and HAART-treated participants, and three determined the association between heavy metal toxicity and non-communicable diseases (liver fibrosis, anaemia, and reproductive parameters, respectively) in HIV-positive patients. Conclusions: Blood lead, cadmium, and mercury levels were higher in HIV-seropositive than -seronegative subjects, whereas serum zinc level was lower in HIV-seropositive than -seronegative subjects, but the causal association between heavy metals and non-communicable diseases in HIV subjects is largely unknown. Interdisciplinary research between nutrition, toxicology, and human health is envisaged for primary and secondary prevention and treatment.

Lagged WQS regression for mixtures with many components

The developmental timing of exposures to toxic chemicals or combinations of chemicals may be as important as the dosage itself. This concept is called "critical windows of exposure." The time boundaries of such windows can be detected if exposure data are collected repeatedly in short time intervals. The development of tooth-matrix biomarkers which provide prenatal and postnatal exposure measures in repeated intervals can provide such data. Using teeth, we use reverse distributed lagged models (DLMs) to incorporate weekly prenatal and postnatal measures of exposures to estimate time-varying associations with developmental effects. The analysis of such data using lagged weighted quantile sum (WQS) regression as an extension to reverse DLMs for complex mixtures was first proposed by Bello et al. This prior algorithm was not operationally generalizable to large numbers of components (say, more than five or six). We propose a revised algorithm that may be useful for larger mixtures by combining time-specific WQS(t) indices in a reverse DLM. We demonstrate the new algorithm using tooth data in association with a neurodevelopmental score and in simulated data from 3 cases wherein different components of a mixture have time varying associations and in the case where none have associations. The new algorithm correctly detects the simulated associations when the number of samples within the time-specific analyses is moderate to large.

Blood Lead Levels in Females of Childbearing Age in Flint, Michigan, and the Water Crisis

OBJECTIVE

To compare blood lead levels in females of childbearing age, 12-50 years, living within and adjacent to Flint, Michigan, before, during, and after the Flint River water exposure and compare the levels to those that have been shown to cause fetal loss and preterm birth.

METHODS

The switch in the community water source to the Flint River occurred on April 25, 2014, and was reverted to the original source on October 15, 2015. Using a retrospective cross-sectional study design using geocoded blood lead levels obtained from all females of childbearing age available from a single hospital database, we compared blood lead levels for the following 18-month time periods: April 25, 2012-October 15, 2013 (PRE), April 25, 2014-October 15, 2015 (DURING), and April 25, 2016-October 15, 2017 (POST).

RESULTS

Results are reported as geometric mean (95% CI). Within Flint, PRE blood lead levels in females of childbearing age were 0.69 micrograms/dL (95% CI 0.63-0.75), DURING blood lead levels were 0.65 micrograms/dL (95% CI 0.60-0.71), and POST blood lead levels were 0.55 micrograms/dL (95% CI 0.54-0.56). DURING Flint River water exposure blood lead levels were not significantly different than the PRE Flint River water time period. POST Flint River water exposure blood lead levels were significantly lower than both PRE and DURING levels. Overall, lower blood lead levels were found outside the Flint boundary in all cohorts.

CONCLUSION

Blood lead levels in Flint females of childbearing age did not increase during the Flint River water exposure and subsequent 18-month time period. Mean blood lead levels during the Flint River water exposure are not consistent with the markedly higher blood lead levels reported in the literature to be associated with fetal loss, low birth weight, or preterm birth.

Lead seasonality in humans, animals, and the natural environment

Lead adversely impacts the health of humans, animals, and the natural environment. Higher lead burdens in warm weather occur in humans, domesticated and wild animals; land and water species; urban and rural, developed and pristine environments. The array of evidence suggests that lead seasonality is multifactorial within the natural world, including humans. Seasonally higher temperatures, solar radiation, humidity and anthropogenic pollution result in lower pH (acidification) in air, water and soil. Environmental acidification increases lead's bioavailability and mobility thus intensifying human, animal and plant exposures. In addition, lead seasonality in the biosphere is influenced by higher growth rates, slightly increased exposures, and more Vitamin D metabolism. Methodologically, we applied a One Health perspective to EPA's Integrated Science Assessments of Lead to review the published literature, supplemented with subsequent and related publications to assess data on the seasonality of lead exposure across species and through the earth's systems. Our integrated assessment suggests that: 1) 'Seasonality' is a multifactorial, terrestrial phenomenon affecting the natural world; human activities have exacerbated natural cyclicities that impact lead exposures across species. 2) To be sustainable, human lead remediation strategies must consider the total environment. 3) Global warming and climate change events may increase lead exposures and toxicity to all species throughout the natural environment.

Blood Lead Levels in Occupationally Exposed Workers Involved in Battery Factories of Delhi-NCR Region: Effect on Vitamin D and Calcium Metabolism

Workers involved in battery manufacturing or recycling factories are occupationally exposed to high concentrations of lead. In humans, lead can cause a wide range of biological effects depending upon the level and duration of exposure. The purpose of this study was to find out the blood lead levels (BLL) in occupationally exposed workers involved in battery industry in Delhi NCR region and to study whether lead affected the vitamin D (vit D) and calcium metabolism. For this study 100 occupationally lead-exposed battery workers (LEBW) and 100 non-lead exposed controls (NLEC) were recruited. BLL were measured using inductively coupled plasma optical emission spectrometer (ICP-OES) technique while ELISA was performed to quantify the serum vit D levels in the study subjects. Routine biochemical parameters were measured by chemistry autoanalyzers. Statistical analysis was done using appropriate statistical tools. Results showed that BLL were significantly higher in LEBW as compared to NLEC (p < 0.0001). Serum vitamin D, calcium and phosphorus levels were significantly decreased in battery workers as compared to controls (p < 0.005). Spearman's rank correlation analysis showed significant negative correlation of BLL with serum Vitamin D and calcium levels. Significant positive correlation was observed between BLL and duration of lead exposure. Weak negative correlation was also observed between BLL and vit D even after adjusting for smoking status. In conclusion, this study demonstrated that higher BLL significantly alters the vit D and calcium metabolism.

Analysis of blood lead levels of young children in Flint, Michigan before and during the 18-month switch to Flint River water

Background: The toxicity of lead, like any xenobiotic, is directly linked to the duration of exposure and toxin concentration in the body. The elevation in blood lead levels (BLLs) in young Flint, Michigan children noted in time-periods before, and during the 18-month exposure to Flint River water (FRW) from 25 April 2014 to 15 October 2015 is well-known internationally. The length of time BLLs were elevated is unknown, yet key in understanding the potential health impact of the event. The objective of this study was to evaluate whether BLLs in Flint children were increased during the entire 18-month FRW exposure compared to similar earlier time periods. Methods: We conducted a retrospective study analyzing BLLs from Flint children aged 5 years and under. The geometric mean (GM) BLLs and percentages of BLLs ≥5.0 μg/dL in Period I: 25 April 2006 to 15 October 2007 (earliest timeframe available for study) and Period II: 25 April 2012 to 15 October 2013 (timeframe immediately before the water switch), were compared to Period III, 25 April 2014 to 15 October 2015 (FRW exposure). Results: There were 5663 BLLs available for study. GM ± SE BLLs decreased from 2.19 ± 0.03 μg/dL in Period I to 1.47 ± 0.02 μg/dL in Period II [95% CI, 0.64, 0.79]; p<.001 and decreased further to 1.32 ± 0.02 µg/dL during the FRW Period III [95% CI, 0.79, 0.95]; p<.001. The percentage of BLLs ≥5.0 μg/dL decreased from Period I (10.6%) to Period II (3.3%) [95% CI, 5.7, 8.8]; p<.001 and from Period I to Period III (3.9%) [95% CI, 5.0, 8.2]; p=.002. The 0.6% increase from Period II to Period III was not statistically significant [95% CI, -1.9, 0.57]; p=.30. Conclusion: Analyses of GM and percentages ≥5.0 μg/dL of BLLs do not support the occurrence of a global increase in BLLs in young children of Flint during the entire 18-month period of FRW exposure.

Blood Lead Levels of Children in Flint, Michigan: 2006-2016

OBJECTIVE

We evaluated the increases in blood lead levels (BLLs) observed in young children in Flint, Michigan, during their exposure to corrosive Flint River water during the years 2014 and 2015 and compared their BLLs to those of Flint children measured during the years 2006-2013 and 2016.

STUDY DESIGN

This was a retrospective study design using BLLs extracted from databases from 2006 to 2016. We analyzed a population sample of 15 817 BLLs from children aged ≤5 years with potential exposure to contaminated Flint River water. Percentages of BLLs ≥5.0 µg/dL and geometric mean (GM) BLLs were analyzed over time.

RESULTS

A significant decline in the percentages of BLLs ≥5.0 µg/dL from 11.8% in 2006 to 3.2% in 2016 was observed (P < .001). GM ± SE BLLs decreased from 2.33 ± 0.04 µg/dL in 2006 to 1.15 ± 0.02 µg/dL in 2016 (P < .001). GM BLLs increased twice: from 1.75 ± 0.03 µg/dL to 1.87 ± 0.03 µg/dL (2010-2011) and from 1.19 ± 0.02 µg/dL to 1.30 ± 0.02 µg/dL (2014-2015). Overall, from 2006 to 2016, there was a 72.9% decrease in the percentage of children with BLLs ≥5.0 µg/dL and a 50.6% decrease in GM BLLs.

CONCLUSION

These findings suggest that the 11 year trend of annual decreases in BLLs in children in Flint, Michigan, reversed to a degree consistent with random variation from 2010 to 2011, and again during the exposure to Flint River water in 2014-2015. Historically, public health efforts to reduce BLLs of young children in Flint have been effective over the 11-year period studied.

Prevalence of exposure of heavy metals and their impact on health consequences

Even in the current era of growing technology, the concentration of heavy metals present in drinking water is still not within the recommended limits as set by the regulatory authorities in different countries of the world. Drinking water contaminated with heavy metals namely; arsenic, cadmium, nickel, mercury, chromium, zinc, and lead is becoming a major health concern for public and health care professionals. Occupational exposure to heavy metals is known to occur by the utilization of these metals in various industrial processes and/or contents including color pigments and alloys. However, the predominant source resulting in measurable human exposure to heavy metals is the consumption of contaminated drinking water and the resulting health issues may include cardiovascular disorders, neuronal damage, renal injuries, and risk of cancer and diabetes. The general mechanism involved in heavy metal-induced toxicity is recognized to be the production of reactive oxygen species resulting oxidative damage and health related adverse effects. Thus utilization of heavy metal-contaminated water is resulting in high morbidity and mortality rates all over the world. Thereby, feeling the need to raise the concerns about contribution of different heavy metals in various health related issues, this article has discussed the global contamination of drinking water with heavy metals to assess the health hazards associated with consumption of heavy metal-contaminated water. A relationship between exposure limits and ultimate responses produced as well as the major organs affected have been reviewed. Acute and chronic poisoning symptoms and mechanisms responsible for such toxicities have also been discussed.

Blood Lead Concentrations of Children in the United States: A Comparison of States Using Two Very Large Databases

OBJECTIVES

To determine whether there are substantial differences by state between 2 large datasets in the proportion of children with elevated blood lead levels (BLLs); to identify states in which the percentage of elevated BLLs is high in either or both datasets; and to compare the percentage of elevated BLLs in individual states with those of children living in Flint, Michigan, during the months when these children were exposed to lead-contaminated drinking water.

STUDY DESIGN

Tables of BLLs for individual states from the Quest Diagnostics and the Centers for Disease Control and Prevention datasets for 2014-2015, containing more than 3 million BLLs of young children?<?6 years old, were constructed to compare the Quest Diagnostics and Centers for Disease Control and Prevention data with one another and with BLLs available for Flint children for 2014-2015.

RESULTS

For some states, the percentages of BLLs ?5.0?µg/dL are similar in the 2 datasets, whereas for other states, the datasets differ substantially in the percentage of BLLs ?5.0?µg/dL. The percentage of BLLs ?5.0?µg/dL is greater in some states in both datasets than observed in Flint when children were exposed to contaminated water.

CONCLUSION

The data presented in this study can be a resource for pediatricians and public health professionals involved in the design of state programs to reduce lead exposure (primary prevention) and identify children with elevated BLLs (secondary prevention).

Vitamin D Insufficiency and Its Association with Biochemical and Anthropometric Variables of Young Children in Rural Southwestern China

BACKGROUND

With recognition of the important roles of Vitamin D (VitD) in various physiological processes, increasing attention has been drawn to the status of VitD in early life. However, the VitD status of young children and the related factors in rural areas of Southwestern China remain unclear. This study aimed to explore VitD status and its seasonal variation in 18-month-old children living in rural Southwestern China. The association of VitD with biochemical and anthropometric variables was also investigated.

METHODS

A total of 177 18-month-old children in a rural area of Yunnan Province, Southwestern China, were enrolled. Serum concentrations of 25-hydroxy Vitamin D (25(OH)D) were measured through high-performance liquid chromatogram-tandem mass spectrometry. Parathyroid hormone (PTH) levels were measured with a chemiluminescence assay. Serum concentrations of calcium, phosphorus, and alkaline phosphatase (ALP) were also measured. Anthropometric data and the outdoor activity time of each participant were collected.

RESULTS

The serum 25(OH)D concentration was 26.61 ± 7.26 ng/ml; concentrations lower than 30 ng/ml accounted for 70.6% of the participants and concentrations lower than 20 ng/ml accounted for 16.4%. The level of serum 25(OH)D was not significantly different among four seasons (P >0.05). A positive relationship was found between 25(OH)D concentration and the time of outdoor activities (r = 0.168, P < 0.05). Serum PTH concentration was negatively correlated with 25(OH)D concentration (r = -0.163, P < 0.05). A positive relationship was found between the serum concentrations of 25(OH)D and calcium (r = 0.154, P < 0.05). No significant association was observed between 25(OH)D and ALP, phosphorus, or anthropometric variables.

CONCLUSIONS

The prevalence of VitD insufficiency is high among young children in the rural Southwestern China regardless of the seasons. VitD supplementation is still essential to maintain VitD sufficiency for children living in rural area.

Evaluation and management of lead exposure

Lead, which is widely used in industry, is a common element found in low concentrations in the Earth's crust. Implementations to reduce environmental lead concentrations have resulted in a considerable reduction of lead levels in the environment (air) and a sustained reduction in the blood lead levels of the average citizen. However, people are still being exposed to lead through a variety of routes in everyday commodities. Lead causes health problems such as toxicity of the liver, kidneys, hematopoietic system, and nervous system. Having a carcinogenic risk as well, the IARC classifies inorganic lead compounds as probably carcinogenic to humans (Group 2A). Occupational lead poisonings have decreased due to the efforts to reduce the lead concentrations in the working environment. In contrast, health hazards associated with long-term environmental exposure to low concentrations of lead have been reported steadily. In particular, chronic exposure to low concentrations of lead has been reported to induce cognitive behavioral disturbances in children. It is almost impossible to remove lead completely from the human body, and it is not easy to treat health hazards due to lead exposure. Therefore, reduction and prevention of lead exposure are very important. We reviewed the toxicity and health hazards, monitoring and evaluation, and management of lead exposure.

Vitamin D, Essential Minerals, and Toxic Elements: Exploring Interactions between Nutrients and Toxicants in Clinical Medicine

In clinical medicine, increasing attention is being directed towards the important areas of nutritional biochemistry and toxicant bioaccumulation as they relate to human health and chronic disease. Optimal nutritional status, including healthy levels of vitamin D and essential minerals, is requisite for proper physiological function; conversely, accrual of toxic elements has the potential to impair normal physiology. It is evident that vitamin D intake can facilitate the absorption and assimilation of essential inorganic elements (such as calcium, magnesium, copper, zinc, iron, and selenium) but also the uptake of toxic elements (such as lead, arsenic, aluminum, cobalt, and strontium). Furthermore, sufficiency of essential minerals appears to resist the uptake of toxic metals. This paper explores the literature to determine a suitable clinical approach with regard to vitamin D and essential mineral intake to achieve optimal biological function and to avoid harm in order to prevent and overcome illness. It appears preferable to secure essential mineral status in conjunction with adequate vitamin D, as intake of vitamin D in the absence of mineral sufficiency may result in facilitation of toxic element absorption with potential adverse clinical outcomes.

Colder-to-warmer changes in children's blood lead concentrations are related to previous blood lead status: results from a systematic review of prospective studies

OBJECTIVE

To estimate the extent of changes in mean BLLs from colder to warmer months, in children aged 1-5 years with different status of lead in colder months.

METHODOLOGY

We performed a systematic review using an in-house algorithm developed in MEDLINE, EMBASE, Web of Science, and CINHAL. Search was performed between November 2012 and July 2013, and data evaluation and extraction were subsequently conducted. The mean BLLs observed in the warmer months was divided by the one observed in the colder months to obtain the warmer-to-colder ratio (WCR). Study-specific WCRs were pooled using the fixed-effects method of Mantel-Haenszel to estimate the combined WCR.

RESULTS

From 4040 papers initially identified, eight cohort studies were considered relevant for inclusion. The combined WCR was inversely related to the BLLs observed during colder months. The values were 1.25 (95% CI: 0.90-1.60), 1.06 (95% CI: 0.92-1.19), and 0.95 (95% CI: 0.51-1.39) for children showing baseline BLLs of <10μgdL(-1), 10-20μgdL(-1)and ≥20μgdL(-1), respectively. The combined WCR was influenced neither by children's age nor place/date of study.

CONCLUSION

The extent of the summer increase in BLLs depends on the BLLs in the colder months.

Association of arsenic and metals with concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D among adolescents in Torreón, Mexico

BACKGROUND

Limited data suggest that lead (Pb), cadmium (Cd), and uranium (U) may disrupt vitamin D metabolism and inhibit production of 1,25-dihydroxyvitamin D [1,25(OH)2D], the active vitamin D metabolite, from 25-hydroxyvitamin D [25(OH)D] in the kidney.

OBJECTIVES

We evaluated the association between blood lead (BPb) and urine arsenic (As), Cd, molybdenum (Mo), thallium (Tl), and U with markers of vitamin D metabolism [25(OH)D and 1,25(OH)2D].

METHODS

We conducted a cross-sectional study of 512 adolescents in Torreón, a town in Mexico with a Pb smelter near residential areas. BPb was measured using atomic absorption spectrometry. Urine As, Cd, Mo, Tl, and U were measured using inductively coupled plasma mass spectrometry. Serum 25(OH)D and 1,25(OH)2D were measured using a chemiluminescent immunoassay and a radioimmunoassay, respectively. Multivariable linear models with vitamin D markers as the outcome were used to estimate associations of BPb and creatinine-corrected urine As and metal concentrations with serum vitamin D concentrations, controlling for age, sex, adiposity, smoking, socioeconomic status, and time outdoors.

RESULTS

Serum 25(OH)D was positively associated with urine Mo and Tl [1.5 (95% CI: 0.4, 2.6) and 1.2 (95% CI: 0.3, 2.1) ng/mL higher with a doubling of exposure, respectively]. Serum 1,25(OH)2D was positively associated with urine As and U [3.4 (95% CI: 0.9, 5.9) and 2.2 (95% CI: 0.7, 3.7) pg/mL higher, respectively], with little change in associations after additional adjustment for serum 25(OH)D. Pb and Cd were not associated with 25(OH)D or 1,25(OH)2D concentrations.

CONCLUSIONS

Overall, our findings did not support a negative effect of As or metal exposures on serum 1,25(OH)2D concentrations. Additional research is needed to confirm positive associations between serum 1,25(OH)2D and urine U and As concentrations and to clarify potential underlying mechanisms.

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.

Association of 25-hydroxyvitamin D with Hb and lead in children: a Chinese population-based study

OBJECTIVE

To evaluate the prevalence of vitamin D deficiency and insufficiency, as well as their association with Hb and elevated blood lead levels (BLL) in children in China.

DESIGN

A cross-sectional and 1-year retrospective study.

SETTING

Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, China.

SUBJECTS

Children aged from 6 months to 14 years living in south-west China who were taken to physical examinations (January-December 2011).

RESULTS

Of 1218 children included in the study, 25-hydroxyvitamin D (25(OH)D) concentration (mean 33.18 (sd 16.48) ng/ml) was deficient in 21.6% and insufficient in 27.4%, which were higher than the prevalence of both anaemia at 8.5% and elevated BLL (Pb ≥ 10 μg/dl) at 1.8%, but lower than mildly elevated BLL prevalence (5 μg/dl ≤ Pb < 10 μg/dl) at 56.9%. There was a negative correlation between 25(OH)D concentration and BLL (r = -0.216, P < 0.001) while no significant relationship was found between 25(OH)D concentration and Hb (r = -0.012, P > 0.05). After multivariable adjustment, the significant predictors of 25(OH)D deficiency and insufficiency were increasing child age especially between 8 and 14 years (OR = 18.29; 95% CI 10.14, 32.99; P < 0.001) and BLL (OR = 1.01; 95% CI 1.00, 1.02; P = 0.045).

CONCLUSIONS

The prevalence of 25(OH)D deficiency and insufficiency was much higher than that of anaemia or elevated BLL in south-west China, and associated with increasing age and BLL.

Newborns and low to moderate prenatal environmental lead exposure: might fathers be the key?

This study is part of the BioMadrid Project, a bio-monitoring study designed to assess pollutants in the environment surrounding children born in the Madrid region. Our aim in this report is to evaluate the association between prenatal lead exposure and fetal development using three biological samples (maternal and paternal blood lead at around 34 weeks of gestation as well as cord blood lead levels), three biomarkers of effect in cord blood peripheral lymphocytes (micronucleus in binucleated cells, nucleoplasmic bridges, and nuclear buds), and different anthropometrical characteristics at birth. Maternal and cord blood lead were not associated with newborn measurements or genotoxicity biomarkers. In contrast, increases in father blood lead were coupled with lower weight (mean difference (MD), -110.8 g; 95% confidence intervals (95%CI), -235.6 to 6.00; p < 0.10) and shorter abdominal (MD, -0.81 cm; 95%CI, -1.64 to 0.00; p < 0.05) and cephalic (MD, -0.32 cm; 95%CI, -0.65 to 0.00; p < 0.05) circumferences at birth as well as with the presence of nucleoplasmic bridges (odds ratio, 1.03; 95%CI, 1.00 to 1.06; p < 0.05) and nuclear buds (odds ratio, 1.02; 95%CI, 0.99 to 1.04; p < 0.10). These associations were mainly confined to female babies, in whom paternal lead was also inversely associated with length. Our results support the hypothesis that paternal lead exposure may be affecting the development of newborns.

Racial disparities in children's blood lead levels: possible implication of divalent metal transporter 1

Adverse effects of lead exposure at low-dose (<10 μg/dL) in children showed a growing interest over the last decades. Black ethnicity is usually associated with elevated blood lead levels (BLLs), independently of age and socioeconomic conditions. The gastrointestinal uptake of lead represents a key step in the process of lead kinetic and toxicity. The involvement of divalent metal transporter 1 (DMT1) in the lead absorption has been previously presumed and reported. I postulate that inter-ethnic differences in DMT1 expression may explain a large part of the racial disparity in children's BLLs, and suggest a few analyses to test this hypothesis. The hypothesis rests on some observations from previous researches. The inverse association between BLLs and iron intake has been reported in both cross-sectional and follow-up studies. It appears that no study specifically addressed the modifying effect of ethnicity in this association. Previous reports suggest that DMT1 is the primary mechanism for gastrointestinal iron absorption. There are four forms of DMT1 expressed in the enterocytes, which did not respond similarly to iron changes. It is not excluded that some children be more likely to uptake ingested lead depending on DMT1 isoform expressed. I hypothesize that the expression of the more active DMT1 isoform (+1A/+IRE) is more common in Non-Hispanic Black compared with Non-Hispanic White children, and I suggest how to test this hypothesis. If the hypothesis is confirmed, this would suggest that the prevention of iron-deficiency must be included in the primary programs for preventing increase of BLLs in Non-Hispanic Black children, rather than as part of secondary prevention. Moreover, thorough studies would be useful to characterize the interaction between environmental lead levels and DMT1 expression in relation to BLLs in young children.

Blood lead concentration is not altered by high-dose vitamin D supplementation in children and young adults with HIV

OBJECTIVES

Optimal vitamin D status is known to have beneficial health effects and vitamin D supplements are commonly used. It has been suggested that vitamin D supplementation may increase blood lead in children and adults with previous lead exposure. The objective was to determine the safety regarding lead toxicity during 12 weeks of high-dose vitamin D3 supplementation in children and young adults with human immunodeficiency virus (HIV).

METHODS

Subjects with HIV (8-24 years) were randomized to vitamin D3 supplementation of 4000 or 7000 IU/day and followed at 6 and 12 weeks for changes in serum 25-hydroxy vitamin D (25D) and whole-blood lead concentration. This was a secondary analysis of a larger study of vitamin D3 supplementation in children and adolescents with HIV.

RESULTS

In 44 subjects (75% African American), the baseline mean ± standard deviation serum 25D was 48.3±18.6 nmol/L. Fifty percent of subjects had baseline serum 25D <50.0 nmol/L. Serum 25D increased significantly with D3 supplementation during the 12 weeks. No subject had a whole-blood lead >5.0 μg/dL at baseline or during subsequent visits. Whole-blood lead and 25D were not correlated at baseline, and were negatively correlated after 12 weeks of supplementation (P=0.014). Whole-blood lead did not differ between those receiving 4000 and 7000 IU of vitamin D3.

CONCLUSIONS

High-dose vitamin D3 supplementation and the concomitant increased serum 25D did not result in increased whole-blood lead concentration in this sample of children and young adults living in a northeastern urban city.

Chronic effects of lead (Pb) on bone properties in red deer and wild boar: relationship with vitamins A and D3

Here we study the occurrence of abnormalities on bone tissue composition and turnover mechanisms through the Pb-mediated disruption of vitamins A and D in wild ungulates living in a lead (Pb)-polluted mining area. Red deer (Cervus elaphus) and wild boar (Sus scrofa) from the mining area had significantly higher liver and bone Pb levels than controls, which were associated with the depletion of liver retinyl esters and the corresponding increase of free retinol levels both in deer and boar from the mining area. Pb-exposed adult deer had lower carbonate content in bone mineral than controls, which was associated with the increased free retinol percentage. In wild boar, the degree of bone mineralization was also positively associated with higher burdens of retinyl esters. These results suggest that Pb-associated changes in bone composition and mineralization is likely influenced by the depletion of vitamin A in wildlife exposed to environmental Pb pollution.

Serum 25-hydroxyvitamin D concentration does not correlate with atopic dermatitis severity

BACKGROUND

An inverse correlation between serum 25-hydroxyvitamin D concentration and atopic dermatitis (AD) severity has been suggested.

OBJECTIVE

To determine if a statistically significant relationship exists between serum 25-hydroxyvitamin D concentration and AD severity.

METHODS

A cross-sectional study was conducted of patients with AD who were 1 to 18 years of age. An objective Severity Scoring of Atopic Dermatitis (SCORAD) and a serum 25-hydroxyvitamin D concentration were measured for each subject. Statistical analysis was performed using appropriate univariate tests and multivariable models.

RESULTS

Ninety-four of 97 enrolled subjects were included in the analysis. Vitamin D deficiency (25-hydroxyvitamin D <20 ng/mL) was present in 37 subjects (39%), insufficiency (25-hydroxyvitamin D 21-29 ng/mL) in 33 (35%), and sufficiency (25-hydroxyvitamin D ≥30 ng/mL) in 24 (26%). The correlation between 25-hydroxyvitamin D concentration and SCORAD was not significant (r = -0.001; P = .99). A multivariate model showed that a lower serum 25-hydroxyvitamin D concentration was significantly associated with age 3 years or older (P < .0001), black race (P < .0001), and winter season (P = .0084).

LIMITATIONS

Limitations of this study include the inability to control for natural sunlight exposure, vitamin D intake, and AD treatment; in addition, only a single time point was captured.

CONCLUSIONS

Serum 25-hydroxyvitamin D concentration is not significantly correlated with AD severity in our pediatric population.

Urinary cadmium in the 1999-2008 U.S. National Health and Nutrition Examination Survey (NHANES)

Chronic low-level cadmium (Cd) exposure is linked to kidney and cardiovascular disease, fractures, and cancer. Diet and smoking are primary sources of exposure in the general population. We analyzed urinary Cd in NHANES 1999-2008 to determine whether levels declined significantly over the decade for U.S. children, teens, and adults (nonsmokers and smokers) and, if so, factors influencing the decline(s). For each subpopulation, we modeled log urinary Cd using variable-threshold censored multiple regression. Models included individual-level covariates (age, gender, BMI, income, race/ethnicity/country of origin, education, survey period), smoking, housing (home age, water source, filter use), and diet (supplement use; 24-h calorie, fat, protein, micronutrient, and Cd-containing food intakes), creatinine, and survey year variables. Geometric mean urinary Cd (ng/mL) declined 20-25% in these subpopulations, and the regressions showed statistically significant declines in later years for teens and adults. While certain covariates were significantly associated with Cd by subpopulation (creatinine; age; BMI; race/ethnicity/origin; education; smokers in the home; serum cotinine; 24-h fat, Mg, Fe intakes; use of dietary supplements), they did not help explain the declines. Instead, unidentified time-related factors appeared responsible. Despite the declines, millions of Americans remain potentially at risk of adverse outcomes associated with low-level Cd exposure.

Demographic, dietary, and biochemical determinants of vitamin D status in inner-city children

BACKGROUND

Reports of clinical rickets are particularly evident in minority infants and children, but only limited analyses of vitamin D are available in this demographic group.

OBJECTIVE

We sought to characterize circulating 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], and their determinants, including circulating parathyroid hormone (PTH), total alkaline phosphatase activity (ALP), calcium, and phosphorus, in minority infants and children.

DESIGN

We obtained demographic information and blood samples for measurement of PTH, ALP, 25(OH)D, and 1,25(OH)(2)D in >750 6-mo- to 3-y-old children. Dietary intake data were obtained and analyzed.

RESULTS

The mean (±SD) 25(OH)D concentration was 66 ± 22 nmol/L (26.3 ± 8.7 ng/dL). A total of 15% of children had 25(OH)D concentrations less than the recommended target threshold of 50 nmol/L. Combined elevations of PTH and ALP occurred in only 2.5% of children. Determinants of 25(OH)D included vitamin D intake, age (decreasing with age), skin type (greater concentrations in lighter-skinned children than in darker-skinned children), formula use (higher intakes), season (greater concentrations in the summer and fall than in the winter and spring), and, inversely, PTH. The mean 1,25(OH)(2)D concentration was 158 ± 58 pmol/L (60.6 ± 22.5 pg/mL), which was consistent with a reference range of 41-274 pmol/L or 15.7-105.5 pg/mL. Determinants for 1,25(OH)(2)D were age (decreasing with age), sex (greater concentrations in girls than in boys), skin type (greater concentrations in lighter-skinned children than in darker-skinned children), and, inversely, serum calcium and phosphorus.

CONCLUSIONS

Although 15% of subjects were vitamin D insufficient, only 2.5% of subjects had elevations of both PTH and ALP. The greater 25(OH)D concentrations observed with formula use confirm that dietary vitamin D fortification is effective in this demographic group. Circulating 1,25(OH)(2)D is higher in infants than in older children and adults and, in contrast to 25(OH)D, is not directly correlated with nutrient intakes.

Vitamin D-fortified milk achieves the targeted serum 25-hydroxyvitamin D concentration without affecting that of parathyroid hormone in New Zealand toddlers

For young children, the level of vitamin D required to ensure that most achieve targeted serum 25-hydroxyvitamin D [25(OH)D] ≥50 nmol/L has not been studied. We aimed to investigate the effect of vitamin D-fortified milk on serum 25(OH)D and parathyroid hormone (PTH) concentrations and to examine the dose-response relationship between vitamin D intake from study milks and serum 25(OH)D concentrations in healthy toddlers aged 12-20 mo living in Dunedin, New Zealand (latitude 46°S). Data from a 20-wk, partially blinded, randomized trial that investigated the effect of providing red meat or fortified toddler milk on the iron, zinc, iodine, and vitamin D status in young New Zealand children (n = 181; mean age 17 mo) were used. Adherence to the intervention was assessed by 7-d weighed diaries at wk 2, 7, 11, 15, and 19. Serum 25(OH)D concentration was measured at baseline and wk 20. Mean vitamin D intake provided by fortified milk was 3.7 μg/d (range, 0-10.4 μg/d). After 20 wk, serum 25(OH)D concentrations but not PTH were significantly different in the milk groups. The prevalence of having a serum 25(OH)D <50 nmol/L remained relatively unchanged at 43% in the meat group, whereas it significantly decreased to between 11 and 15% in those consuming fortified study milk. In New Zealand, vitamin D intake in young children is minimal. Our findings indicate that habitual consumption of vitamin D-fortified milk providing a mean intake of nearly 4 μg/d was effective in achieving adequate year-round serum 25(OH)D for most children.

Proton magnetic resonance spectroscopy in adults with childhood lead exposure

BACKGROUND

Childhood lead exposure adversely affects neurodevelopment. However, few studies have examined changes in human brain metabolism that may underlie known adverse cognitive and behavioral outcomes.

OBJECTIVE

We examined the association between mean childhood blood lead levels and in vivo brain metabolite concentrations as adults, determined by proton magnetic resonance spectroscopy (MRS) in a birth cohort with documented low-to-moderate lead exposure.

METHODS

Adult participants from the Cincinnati Lead Study [n = 159; mean age (± SD), 20.8 ± 0.9 years] completed a quantitative, short-echo proton MRS protocol evaluating seven regions to determine brain concentrations of N-acetyl aspartate (NAA), creatine and phosphocreatine (Cr), cholines (Cho), myo-inositol, and a composite of glutamate and glutamine (GLX). Correlation and multiple linear regression analyses were conducted.

RESULTS

Mean childhood blood lead levels were associated with regionally specific brain metabolite concentrations adjusted for age at imaging and Full-Scale intelligence quotient. Adjusted analyses estimated for a unit (micrograms per deciliter) increase in mean childhood blood lead concentrations, a decrease of NAA and Cr concentration levels in the basal ganglia, a decrease of NAA and a decrease of Cho concentration levels in the cerebellar hemisphere, a decrease of GLX concentration levels in vermis, a decrease of Cho and a decrease of GLX concentration levels in parietal white matter, and a decrease of Cho concentration levels in frontal white matter.

CONCLUSIONS

Gray-matter NAA reductions associated with increasing childhood blood lead levels suggest that sustained childhood lead exposure produces an irreversible pattern of neuronal dysfunction, whereas associated white-matter choline declines indicate a permanent alteration to myelin architecture.

Interactions of lifetime lead exposure and stress: behavioral, neurochemical and HPA axis effects

Lead (Pb) and stress co-occur as risk factors, share biological substrates and produce common adverse effects. We previously found that prenatal restraint stress (PS) or offspring stress (OS) could enhance maternal Pb-induced behavioral, brain neurotransmitter level and HPA axis changes. The current study examined how lifetime Pb exposure, consistent with human environmental exposure, interacts with stress. Dams were exposed to Pb beginning 2 mos prior to breeding (0, 50 or 150ppm in drinking water), PS on gestational days 16 and 17, or the combination. Offspring continued on the same Pb exposure as the dam. A subset of Pb+PS offspring also received 3 additional stress challenges (OS), yielding 9 exposure groups/gender: 0-NS, 0-PS, 0-OS, 50-NS, 50-PS, 50-OS, 150-NS, 150-PS and 150-OS. As with maternal Pb (Virgolini et al., 2008a), lifetime Pb and stress influenced Fixed Interval (FI) behavior primarily in females. Relative to 0-NS control, reductions in postreinforcement pause (PRP) times were seen only with combined Pb+PS (50-PS, 50-OS, 150-PS). Stress increased FI response rates when Pb alone was without effect (150-PS, 150-OS), but gradually mitigated rate increases produced by Pb alone (50-PS, 50-OS), effects that appear to be due primarily to PS, as they were of comparable magnitude in PS and OS groups. Individual subject data suggest that enhanced Pb and PS effects reflect increasing numbers of subjects shifting to the high end of the normal range of FI performance values, consistent with a dose-response type of Pb+stress additivity. Consistent with reports of cortico-striatal mediation of both interval timing (PRP) and FI rates, principal component analyses suggested potential mediation via altered frontal cortex norepinephrine, reduced nucleus accumbens dopaminergic control and enhanced striatal monoamine control. Altered FI performance, whether occurring through changes in response rate, PRP, or both, represent behavioral inefficiency and potentially sub-optimal or even dysfunctional resource/energy use.

Control of Alzheimer's amyloid beta toxicity by the high molecular weight immunophilin FKBP52 and copper homeostasis in Drosophila

FK506 binding proteins (FKBPs), also called immunophilins, are prolyl-isomerases (PPIases) that participate in a wide variety of cellular functions including hormone signaling and protein folding. Recent studies indicate that proteins that contain PPIase activity can also alter the processing of Alzheimer's Amyloid Precursor Protein (APP). Originally identified in hematopoietic cells, FKBP52 is much more abundantly expressed in neurons, including the hippocampus, frontal cortex, and basal ganglia. Given the fact that the high molecular weight immunophilin FKBP52 is highly expressed in CNS regions susceptible to Alzheimer's, we investigated its role in Aβ toxicity. Towards this goal, we generated Aβ transgenic Drosophila that harbor gain of function or loss of function mutations of FKBP52. FKBP52 overexpression reduced the toxicity of Aβ and increased lifespan in Aβ flies, whereas loss of function of FKBP52 exacerbated these Aβ phenotypes. Interestingly, the Aβ pathology was enhanced by mutations in the copper transporters Atox1, which interacts with FKBP52, and Ctr1A and was suppressed in FKBP52 mutant flies raised on a copper chelator diet. Using mammalian cultures, we show that FKBP52 (−/−) cells have increased intracellular copper and higher levels of Aβ. This effect is reversed by reconstitution of FKBP52. Finally, we also found that FKBP52 formed stable complexes with APP through its FK506 interacting domain. Taken together, these studies identify a novel role for FKBP52 in modulating toxicity of Aβ peptides.

Vitamin D production after UVB exposure depends on baseline vitamin D and total cholesterol but not on skin pigmentation

UVB radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) (25(OH)D), but the influence of skin pigmentation, baseline 25(OH)D level, and total cholesterol has not been well characterized. To determine the importance of skin pigmentation, baseline 25(OH)D level, and total cholesterol on 25(OH)D production after UVB exposure, 182 persons were screened for 25(OH)D level. A total of 50 participants with a wide range in baseline 25(OH)D levels were selected to define the importance of baseline 25(OH)D level. Of these, 28 non-sun worshippers with limited past sun exposure were used to investigate the influence of skin pigmentation and baseline total cholesterol. The participants had 24% of their skin exposed to UVB (3 standard erythema doses) four times every second or third day. Skin pigmentation and 25(OH)D levels were measured before and after the irradiations. Total cholesterol was measured at baseline. The increase in 25(OH)D level after UVB exposure was negatively correlated with baseline 25(OH)D level (P<0.001) and positively correlated with baseline total cholesterol level (P=0.005), but no significant correlations were found with constitutive or facultative skin pigmentation. In addition, we paired a dark-skinned group with a fair-skinned group according to baseline 25(OH)D levels and found no differences in 25(OH)D increase after identical UVB exposure.

Prenatal lead exposure enhances methamphetamine sensitization in rats

Adult female rats were exposed to lead-free sodium acetate via gavage [0 mg (vehicle control)] or to 16 mg lead as lead acetate for 30 days prior to breeding. Following confirmation of breeding, the female animals continued to be exposed to their respective doses throughout gestation and lactation. When weaned, 16 control and 16 lead-exposed offspring were placed on regular water and food (lead-exposure was discontinued) until postnatal day (PND) 70. At this time, one-half of the control animals and one-half of the lead-treatment animals received intraperitoneal (i.p.) injections of the vehicle (saline) for 10 successive days and the remaining animals in each exposure conditions received daily injections of 1.0 mg/kg (+)-methamphetamine (METH) for 10 days (N=8/group). Locomotion in automated chambers was monitored daily for 45 min post-injection. Subsequently, during dose-effect testing, all animals received consecutive daily i.p. injections of 0, 1.0, 2.0, and then 4.0 mg/kg METH. The results of the experiment showed that both control and lead-exposed animals exhibited heightened locomotor activity (i.e. behavioral sensitization) to the repeated administration of 1.0 mg/kg METH. More importantly, animals developmentally (perinatally) exposed to lead showed more rapid sensitization than did their control counterparts. These data indicate that early lead exposure increases sensitivity to the locomotor-stimulating effects of METH. In contrast, identically exposed lead animals exhibit diminished METH dose-effect responding when tested in an intravenous (i.v.) self-administration paradigm [Rocha A., Valles R., Bratton G.R., Nation J.R. Developmental lead exposure alters methamphetamine self-administration in the male rat: acquisition and reinstatement. Drug Alcohol Depend 2008a;95:23-29, Rocha A., Valles R., Hart N., Bratton G.R., Nation J.R. Developmental lead exposure attenuates methamphetamine dose-effect self-administration performance and progressive ratio responding in the male rat. Pharmacol Biochem Behav 2008b;89:508-514].

Plasma 25-hydroxyvitamin D levels in young children undergoing placement of tympanostomy tubes

OBJECTIVES

We report the plasma 25-hydroxyvitamin D [25(OH)D] levels of 16 young children who were undergoing ambulatory surgery for placement of tympanostomy tubes.

METHODS

We previously obtained blood samples from young children who were undergoing ambulatory surgery and reported that they had lower blood levels than adults of eicosapentaenoic acid (an omega-3 fatty acid), vitamin A, and selenium. Plasma frozen continuously at -80 degrees C was available from 16 subjects who were undergoing placement of tympanostomy tubes.

RESULTS

The mean (+/- SD) age of the patients was 3.7 +/- 1.6 years (median, 2.9 years; range, 1.9 to 7.4 years). Sixty-two percent were male; half were white, and half were Hispanic. Sixty-two percent were private patients; the parents reported that half were taking vitamin supplements. None had a history of rickets. None had 25(OH)D levels less than 10 ng/mL; 50% had 25(OH)D levels less than 20 ng/mL (deficient in adults); another 31% had levels from 21 to 29 ng/mL (insufficient in adults).

CONCLUSIONS

Vitamin D is essential for the production of endogenous antimicrobial peptides, and has been linked to seasonal, epidemic influenza A. However, the level of 25(OH)D needed to prevent infection with various human pathogens has not been defined. In view of increasing bacterial resistance and emerging new pathogens, further research on the relationship of infection to 25(OH)D and other nutritional factors is warranted.

Lead exposures in U.S. Children, 2008: implications for prevention

OBJECTIVE

We reviewed the sources of lead in the environments of U.S. children, contributions to children's blood lead levels, source elimination and control efforts, and existing federal authorities. Our context is the U.S. public health goal to eliminate pediatric elevated blood lead levels (EBLs) by 2010.

DATA SOURCES

National, state, and local exposure assessments over the past half century have identified risk factors for EBLs among U.S. children, including age, race, income, age and location of housing, parental occupation, and season.

DATA EXTRACTION AND SYNTHESIS

Recent national policies have greatly reduced lead exposure among U.S. children, but even very low exposure levels compromise children's later intellectual development and lifetime achievement. No threshold for these effects has been demonstrated. Although lead paint and dust may still account for up to 70% of EBLs in U.S. children, the U.S. Centers for Disease Control and Prevention estimates that >or=30% of current EBLs do not have an immediate lead paint source, and numerous studies indicate that lead exposures result from multiple sources. EBLs and even deaths have been associated with inadequately controlled sources including ethnic remedies and goods, consumer products, and food-related items such as ceramics. Lead in public drinking water and in older urban centers remain exposure sources in many areas.

CONCLUSIONS

Achieving the 2010 goal requires maintaining current efforts, especially programs addressing lead paint, while developing interventions that prevent exposure before children are poisoned. It also requires active collaboration across all levels of government to identify and control all potential sources of lead exposure, as well as primary prevention.

Developmental lead exposure alters methamphetamine self-administration in the male rat: acquisition and reinstatement

The rate of acquisition of drug self-administration and the return to drug seeking are important elements of the overall drug profile, and are essential factors in understanding risks associated with drug abuse. Experiment 1 examined the effects of perinatal (gestation/lactation) lead exposure on adult rates of acquisition of intravenous (i.v.) methamphetamine self-administration. Experiment 2 investigated the effects of perinatal lead exposure on drug-maintained responding in a reinstatement (relapse) paradigm. In Experiment 1, female rats were gavaged daily with 0 or 16 mg lead for 30 days prior to breeding with nonexposed males. Lead exposure continued through gestation and lactation and was discontinued at weaning (postnatal day [PND] 21). Male rats born to control or lead-exposed dams were tested daily as adults in an acquisition paradigm that incorporated both Pavlovian and operant components. An initial 3-h autoshaping period preceded a 3-h self-administration period. For 35 daily training sessions i.v. methamphetamine infusions [inf] (0.02 mg/kg) were paired with the extension and retraction of a lever (autoshaping), while inf occurred during self-administration only when a lever press was executed (FR-1). In Experiment 2 animals developmentally exposed to lead were trained on an FR-2 to self-administer methamphetamine (0.04 mg/kg/inf) and then placed on an extinction schedule prior to receiving intraperitoneal (i.p.) priming injections of saline, 0.50, 1.00, or 1.50 mg/kg methamphetamine. The findings from Experiment 1 showed that acquisition was delayed in rats born to lead-exposed dams gavaged daily with 16 mg lead throughout gestation and lactation when a 0.02-mg/kg/inf of methamphetamine served as the reinforcement outcome. Additional data from Experiment 2 indicated priming cues (injections of methamphetamine [i.p.]) administered after extinction were less likely to occasion a return to drug seeking (relapse) in the 16-mg group relative to the 0-mg control group. These results suggest perinatal lead exposure alters patterns of methamphetamine self-administration during the adult cycle.

Developmental lead exposure attenuates methamphetamine dose-effect self-administration performance and progressive ratio responding in the male rat

Perinatal (gestation/lactation) lead exposure modifies the reinforcement efficacy of various psychoactive drugs (e.g., cocaine, opiates) across the phases of initial selection, use, and abuse [Nation J.R., Cardon A.L., Heard H.M., Valles R., Bratton G.R. Perinatal lead exposure and relapse to drug-seeking behavior in the rat: a cocaine reinstatement study. Psychopharmacol 2003;168: 236-243.; Nation J.R., Smith K.R., Bratton G.R. Early developmental lead exposure increases sensitivity to cocaine in a self-administration paradigm. Pharmacol Biochem Behave 2004; 77: 127-13; Rocha A., Valles R., Cardon A.L., Bratton G.R., Nation J.R. Enhanced acquisition of cocaine self-administration in rats developmentally exposed to lead. Neuropsychopharmacol 2005; 30: 2058-2064.]. However, changes in sensitivity to methamphetamine across the phases of drug abuse have not been examined in animals perinatally exposed to lead. Because the mainstream popularity of methamphetamine in the United States is increasing and lead exposure continues to be widespread, an examination of this drug and how it may be modified by perinatal exposure to lead is warranted. The studies reported here examined the effects of perinatal lead exposure on adult self-administration of intravenous (i.v.) methamphetamine across the maintenance phase of drug addiction. Experiment 1 examined dose-effect patterns in control and lead-exposed animals. Experiment 2 evaluated control and lead-exposed animals in a progressive ratio task. Female rats were administered a 16-mg lead or a control solution for 30 days prior to breeding with non-exposed males. Exposure continued through pregnancy and lactation and was discontinued at weaning (postnatal day [PND] 21). Animals born to control or lead-exposed dams received indwelling jugular catheters as adults (PND 70) and subsequently were randomly assigned to one of the two studies, using only one male rat per litter for each study. The data showed a general attenuation of the reinforcement efficacy of methamphetamine in animals perinatally exposed to lead, as compared to control animals.

Nonlinear association between soil lead and blood lead of children in metropolitan New Orleans, Louisiana: 2000-2005

Metropolitan New Orleans is unique because it has a universal blood lead (BL) screening dataset (n=55,551) from 2000-2005 spatially coupled with a soil lead (SL) dataset (n=5467) completed in 2000. We evaluated empirical associations between measurements of SL and BL exposure responses of children in New Orleans by stratifying the databases by Census Tracts and statistically analyzing them with permutation methods. A consistent curvilinear association occurred annually between SL and BL with robust significance (P-values<10(-23)). The mathematical model of the pooled BL datasets for 2000-2005 is: BL=2.038+0.172 x (SL)(0.5) (agreement (R) of 0.534, an r(2) of 0.528, and a P-value of 1.0 x 10(-211)) indicating that chance alone cannot explain the association. Below 100 mg/kg SL children's BL exposure response is steep (1.4 microg/dL per 100 mg/kg), while above 300 mg/kg SL the BL exposure response is gradual (0.32 microg/dL per 100 mg/kg). In 1995, the BL prevalence was 37%>or=10 microg/dL for the most vulnerable poor and predominantly African-American children. In the era of universal screening the prevalence of elevated BL is 11.8%>or=10 microg/dL for the general population of children. The SL map describes community variations of potential BL exposure. If health effects occur at BL>or=2 microg/dL, then 93.5% of the children in New Orleans are at risk. These results reinforce the proposal that prevention of childhood Pb exposure must include SL remediation as demonstrated by a New Orleans pilot project and a proactive Norwegian government program.