Maternal Perchlorate Exposure and offspring Neurodevelopment

Taylor PN, Okosieme OE, Murphy R, Hales C, Chiusano E, Maina A, Joomun M, Bestwick JP, Smyth P, Paradice R, Channon S, Braverman LE, Dayan CM, Lazarus JH, Pearce EN Maternal perchlorate levels in women with borderline thyroid function during pregnancy and the cognitive development of their offspring: data from the controlled antenatal thyroid study. The Journal of Clinical Endocrinology and Metabolism 2014 Nov;99(11):4291-8. doi: 10.1210/jc.2014-1901

Thyroid dysfunction is associated with impaired cognitive development. Perchlorate decreases thyroidal iodine uptake, potentially reducing thyroid hormone production. It is unclear whether perchlorate exposure in early life affects neurodevelopment.

DESIGN: Historical cohort analysis.

PATIENTS: From 2002 to 2006, 21,846 women at gestational age <16 weeks recruited from antenatal clinics in Cardiff, UK and Turin, Italy were enrolled in the Controlled Antenatal Thyroid Screening Study (CATS). We undertook a retrospective analysis of 487 mother-child pairs in mothers who were hypothyroid/hypothyroxinemic during pregnancy and analyzed whether first trimester maternal perchlorate levels in the highest 10% of the study population were associated with increased odds of offspring IQ being in the lowest 10% at 3 years of age.

MAIN OUTCOME MEASURES: Maternal urinary perchlorate, offspring IQ.

RESULTS: Urine perchlorate was detectable in all women (median 2.58 μg/L); iodine levels were low (median 72 μg/L). Maternal perchlorate levels in the highest 10% of the population increased the odds of offspring IQ being in the lowest 10% OR = 3.14 (95% CI 1.38, 7.13) P = .006 with a greater negative impact observed on verbal OR = 3.14 (95% CI 1.42, 6.90) P = .005 than performance IQ. Maternal levothyroxine therapy did not reduce the negative impact of perchlorate on offspring IQ.

CONCLUSIONS: This is the first study using individual-level patient data to study maternal highlight perchlorate exposure and offspring neurodevelopment and suggests that high-end maternal perchlorate levels in hypothyroid/hypothyroxinemic pregnant women have an adverse effect on offspring cognitive development, not affected by maternal levothyroxine therapy. These results require replication in additional studies, including in the euthyroid population.

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Mr. Mitt Romney Gives False Hope, Unfit for Political Office

Regardless of whether one agrees or disagrees Mr. Romney shows once again that he does not have the judgement nor the understanding of the times to be a Presidential candidate. We do not need another “divider”in any political office.

“Former Massachusetts Governor and failed presidential candidate Mitt Romney believes Republicans should “swallow hard” and pass a permanent amnesty bill in the wake of President Barack Obama’s executive amnesty that even Romney conceded would encourage more illegal immigrants to enter the country.” click here

Effects of Environmental Perchlorate Exposure Remain Controversial

Leung AM, Pearce EN, Braverman LE. Environmental perchlorate exposure: potential adverse thyroid effects. Current Opinion in Endocrinology, Diabetes, and Obesity. 2014 Oct;21(5):372-6. doi: 10.1097/MED.0000000000000090

PURPOSE OF REVIEW: This review will present a general overview of the sources, human studies, and proposed regulatory action regarding environmental perchlorate exposure.

RECENT FINDINGS: Some recent studies have reported significant associations between urinary perchlorate concentrations, thyroid dysfunction, and decreased infant intelligence quotient in groups who would be particularly susceptible to perchlorate effects. An update regarding the recently proposed regulatory actions and potential costs surrounding amelioration of perchlorate contamination is provided.

SUMMARY: The potential adverse thyroidal effects of environmental perchlorate exposure remain controversial, and further research is needed to further define its relationship to human health among pregnant and lactating women and their infants.

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Perchlorate in the Great Lakes Predominantly Natural in Origin

Poghosyan A, Sturchio NC, Morrison CG, Beloso AD Jr, Guan Y, Eiler JM, Jackson WA, Hatzinger PB. Perchlorate in the Great Lakes: isotopic composition and origin. Environ Sci Technol. 2014 Oct 7;48(19):11146-53. doi: 10.1021/es502796d. Epub 2014 Sep 12.

Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ(18)O, Δ(17)O) and chlorine (δ(37)Cl) along with the abundance of the radioactive isotope (36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 μg per liter. δ(37)Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas δ(18)O values range from -4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ(17)O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∼+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The (36)Cl/Cl ratio of perchlorate varies widely from 7.4 × 10(-12) (Lake Ontario) to 6.7 × 10(-11) (Lake Superior). These (36)ClO4(-) abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high (36)ClO4(-) abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of (36)Cl-enriched perchlorate deposited during the period of elevated atmospheric (36)Cl activity following thermonuclear bomb tests in the Pacific Ocean.

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Benefits of Reducing Perchlorate in Drinking Water: Low, if Any

There is little benefit to reducing perchlorate in drinking water compared to the cost. The push for regulation is a political effort, not sound national regulatory policy.

Lutter R. An upper-bound assessment of the benefits of reducing perchlorate in drinking water. Risk analysis 2014 Oct;34(10):1944-56. doi: 10.1111/risa.12261. Epub 2014 Sep 5.

The Environmental Protection Agency plans to issue new federal regulations to limit drinking water concentrations of perchlorate, which occurs naturally and results from the combustion of rocket fuel. This article presents an upper-bound estimate of the potential benefits of alternative maximum contaminant levels for perchlorate in drinking water. The results suggest that the economic benefits of reducing perchlorate concentrations in drinking water are likely to be low, i.e., under $2.9 million per year nationally, for several reasons. First, the prevalence of detectable perchlorate in public drinking water systems is low. Second, the population especially sensitive to effects of perchlorate, pregnant women who are moderately iodide deficient, represents a minority of all pregnant women. Third, and perhaps most importantly, reducing exposure to perchlorate in drinking water is a relatively ineffective way of increasing iodide uptake, a crucial step linking perchlorate to health effects of concern.

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Urinary Thiocyanate Associated with Adult Cancer, Lung Problems

Shiue I. Urinary thiocyanate concentrations are associated with adult cancer and lung problems: US NHANES, 2009-2012. Environ Sci Pollut Res Int. 2014 Nov 5. 

Links between environmental chemicals and human health have emerged but the effects from perchlorate, nitrate and thiocyanate were unclear. Therefore, it was aimed to study the relationships of urinary perchlorate, nitrate and thiocyanate concentrations and adult health conditions in a national and population-based study. Data was retrieved from US National Health and Nutrition Examination Surveys, 2009-2012, including demographics, blood pressure readings, self-reported health conditions and urinary perchlorate, nitrate and thiocyanate concentrations. Analyses included chi-square test, t test survey-weighted logistic regression models and population attributable risk estimation. There were no clear associations between urinary perchlorate concentrations and adult health conditions, although people with hearing loss and diabetes could be at the borderline risk. Urinary thiocyanate concentrations were significantly associated with emphysema (odds ratio (OR) 2.70 95% confidence intervals (CI) 1.91-3.82, P < 0.001), cancer (OR 1.21 95%CI 1.06-1.39, P = 0.008), chronic bronchitis (OR 1.23 95%CI 1.10-1.52, P = 0.003), wheezing (OR 1.24 95%CI 1.05-1.46, P = 0.011), coughing (OR 1.19 95%CI 1.03-1.37, P = 0.018) and sleep complaints (OR 1.14 95%CI 1.02-1.26, P = 0.019). The population attributable risks accounted for 3.3 % (1.8-5.3 %), 1.9 % (0.6-3.5 %), 1.2 % (0.5-2.6 %), 2.2 % (0.5-4.1 %), 1.8 % (0.3-6.2 %) and 1.3 % (0.2-2.4 %) for emphysema, cancer, chronic bronchitis, wheezing, coughing and sleep complaints, respectively. In addition, there was an inverse association observed between urinary nitrate level and heart failure. This is for the first time observing significant risk effects of urinary thiocyanate concentrations on adult cancer and lung problems, although the causality cannot be established. Elimination of such environmental chemical in humans should be included in future health policy and intervention programs.

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Chronic Fluorosis Associated with Learning Deficits, Memory Loss?

Dong YT, Wang Y, Wei N, Zhang QF, Guan ZZ. Deficit in learning and memory of rats with chronic fluorosis correlates with the decreased expressions of M1 and M3 muscarinic acetylcholine receptors. Archives of Toxicology 2014 Nov 23.

To reveal the molecular mechanism of deficit in learning and memory induced by chronic fluorosis, the expression of muscarinic acetylcholine receptors (mAChRs) and oxidative stress were investigated. Sixty Sprague-Dawley (SD) rats were divided randomly into two groups (30 cases in each), i.e., the control group (<0.5 ppm fluoride in drinking water) and the fluoride group (50 ppm fluoride) for 10 months of treatment. The pups born from SD mothers with or without chronic fluorosis were selected at postnatal days 1, 7, 14, 21 and 28 for experiments (10 for each age). Spatial learning and memory were evaluated by Morris water maze test. The expressions of M1 and M3 mAChRs at the protein and mRNA levels were determined by Western blotting and real-time PCR, respectively. In addition, the contents of ·OH, H2O2, O2 ·- and malondialdehyde (MDA), and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in brains were quantitated by biochemical methods. Our results showed that as compared to controls, the abilities of learning and memory were declined in the adult rats and the offspring rats of postnatal day 28 in the fluoride groups; the expressions of both M1 and M3 mAChRs were significantly reduced at protein and mRNA levels; and the levels of ·OH, H2O2, O2 ·- and MDA were significantly increased, while the activities of SOD and GSH-Px decreased. Interestingly, the decreased protein levels of M1 and M3 mAChRs were significantly correlated with the deficits of learning and memory and high level of oxidative stress induced by chronic fluorosis. Our results suggest that the mechanism for the deficits in learning and memory of rats with chronic fluorosis may be associated with the decreased expressions of M1 and M3 in mAChRs, in which the changes in the receptors might be the result of the high level of oxidative stress occurring in the disease.