Folic Acid May Reduce Risk of Autism Associated With Pesticide Exposure During Pregnancy

MedicalResearch.com Interview with:

Rebecca J. Schmidt, M.S., Ph.D.  Assistant Professor, Public Health Sciences UC Davis California

Dr. Schmidt

Rebecca J. Schmidt, M.S., Ph.D. 
Assistant Professor, Public Health Sciences
UC Davis California

MedicalResearch.com: What is the background for this study?

Response: Maternal folic acid taken near conception has been linked to reduced risk for autism in the child in previous studies.

Separate studies show that exposure to pesticides during pregnancy is associated with increased risk for autism.

Animal studies demonstrate that folic acid and other B-vitamins can attenuate effects of certain environmental contaminants, including pesticides.

This case-control study examined combined maternal folic acid and pesticide exposures in relation to autism in the child.

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Adverse Birth Outcomes and Agricultural Pesticide Use in the San Joaquin Valley of California

MedicalResearch.com Interview with:

Ashley Larsen, PhD Assistant professor Bren School of Environmental Science & Management University of California, Santa Barbara

Dr. Larsen

Ashley Larsen, PhD
Assistant professor
Bren School of Environmental Science & Management
University of California, Santa Barbara

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The relationship between pesticides and adverse birth outcomes has been recognized as an important question for quite some time, and there have been many good studies on the topic. Since randomly exposing people to different levels of pesticides is clearly unethical, researchers focused on the health consequences of non-occupational pesticide exposure often have to choose between detailed studies that follow a couple hundred or couple thousand individuals through pregnancy or larger scale studies that use easier to observe, but less accurate metrics of pesticide exposure (e.g. nearby crops or crop types). Here we tried to provide complementary insight by bridging the gap between detail and scale using detailed pesticide use data and individual birth certificate records for hundreds of thousands of births in an agriculturally dominated region of California. While we found negative effects of pesticide use on birth outcomes including low birth weight, preterm birth and birth abnormalities, these effects were generally in the magnitude of a 5-9% increase in probability of an adverse outcome, and only observed for individuals exposed to very high levels of pesticides.

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Arsenic Still Found In Infant Rice Products

MedicalResearch.com Interview with:

Dr. Antonio J. Signes-Pastor, PhD Institute for Global Food Security Queen’s University Belfast Belfast, Northern Ireland, United Kingdom, Department of Epidemiology, Geisel School of Medicine Dartmouth College Lebanon, NH

Dr. Signes-Pastor

Dr. Antonio J. Signes-Pastor, PhD
Institute for Global Food Security
Queen’s University Belfast
Belfast, Northern Ireland, United Kingdom,
Department of Epidemiology, Geisel School of Medicine
Dartmouth College Lebanon, NH

MedicalResearch.com: What is the background for this study?

Response: Inorganic arsenic is a human carcinogen, which has also been associated with several adverse health effects including neurological, cardiovascular, respiratory, and metabolic outcomes. Early life exposure is of particular concern since it may adversely impact on lifetime health outcomes. If low inorganic arsenic drinking water is available the main source of exposure is the diet, especially rice and rice-based products, which are widely used during weaning and to feed infants and young children. In order to reduce exposure, the EU has recently regulated (1st January 2016) the inorganic arsenic maximum level of 0.1 mg/kg for rice products addressed to infants and young children. This level is also under consideration by the US FDA.

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Excessive Rainfall May Be Linked To Autism Through Nitrous Oxide Exposure

MedicalResearch.com Interview with:
Keith Fluegge BS
Institute of Health and Environmental Research (IHER) Cleveland
Graduate School, The Ohio State University, Columbus
Ohio

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The research letter discusses the possible link between rainfall precipitation and risk of autism. Earlier research suggested a link, although there remained quite a bit of skepticism surrounding the findings at the time.

The purpose of the study was to briefly highlight the role of environmental exposure to the agricultural and combustion pollutant, nitrous oxide (N2O), as a possible etiological factor in neurodevelopmental disorders. We have published a series of epidemiological investigations, reviews, and correspondences discussing this possibility. In my continued research on this topic, I learned that rainfall and extreme weather-related events, like hurricanes, drive N2O emissions, especially from nitrogen amended soils. Exposure to this particular air pollutant may, therefore, plausibly undergird the relationship between rainfall precipitation and risk of autism.

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Exposure to BPA Substitute, BPS, Multiplies Breast Cancer Cells

Sumi Dinda

Dr. Sumi Dinda

MedicalResearch.com Interview with:
Sumi Dinda, PhD, NRP, IC.

Associate Professor
Biomedical Diagnostic and Therapeutic Sciences,
School of Health Sciences and
Adjunct Associate Professor
Department of Biological Sciences
School of Health Sciences
Oakland University
Rochester, MI 48309.


MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Bisphenol-S (BPS), a substitute for bisphenol-A (BPA), has been suggested to be an endocrine disrupting compound interfering with normal hormonal activity. This bisphenol analogue is found in plastic substitutes, paper currency, and most products marked “BPA free.” Endocrine disrupting compounds interfere with the normal hormonal activity in the body.

Bisphenols, specifically, disrupt the proper functioning of estrogen receptors, such as ERα causing interference with the normal activity of the hormone estrogen. Studies suggest BPS induces ERα pathways via its estrogen-mimicking properties in the body causing increased cell proliferation resulting in increased breast cancer risk. Despite the hope of a safer substitute, studies have shown that BPS exhibits similar estrogenic activity compared to its analogue BPA, due to their structural commonalities.

BRCA1 is a commonly mutated gene in breast cancer; therefore, it is also important to study the effects of BPS on the expression of this protein. The potency of the endocrine disrupting abilities of BPS compared to BPA could show whether BPS is a suitable alternative to BPA in many everyday products.

The results of this study may contribute to the understanding of the relationship between ERα, BRCA1 expression and Bisphenol-S in breast cancer treatment and prevention.

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Pyrethroid Pesticides Linked To Earlier Puberty in Boys

MedicalResearch.com Interview with:

Jing Liu, Ph.D. Associate Professor College of Environmental & Resource Sciences Zhejiang University Hangzhou, China

Dr. Jing Liu

Jing Liu, Ph.D.
Associate Professor
College of Environmental & Resource Sciences
Zhejiang University
Hangzhou, China

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: In addition to consistent observations of earlier pubertal onset in female since late 19th century, acceleration in male pubertal development also has been reported in more recent studies. Improved nutrition, health and living conditions may contribute to the secular trend towards an earlier pubertal onset. However, the potential role of environmental agents, specifically endocrine-disrupting chemicals (EDCs), also has been emphasized.

Pyrethroids are among the currently used pesticide classes placed on the list of the US Environmental Protection Agency (EPA) as potential EDCs. Pyrethroids are one of the top 10 classes of pesticides and account for greater than 30% of global insecticide usage. Increased human exposure to pyrethroids is thought to occur mainly via residues in diets and indoor residential use. The metabolites of pyrethroids have been widely identified in urine samples of adults, children and adolescents worldwide and the detection rate is usually more than 60% in human populations.

Here, we recognize pyrethroids as a new environmental contributor to the observed secular trend toward earlier male sexual maturity. For the first time to our knowledge, this work reveal a significant and positive association between pyrethroids exposure and gonadotropins levels in 463 Chinese boys, in which a 10% increase in 3-PBA (a common urinary metabolite of pyrethroids) is associated with more than 2% increase in both LH and FSH. Boys with increased urinary levels of 3-PBA have a significantly increased risk of earlier pubertal development, in which the odds of being in an advanced testicular volume and genitalia stage are increase by 113% and 268%, respectively.

Because it is difficult to test the direct causality of environmental risk factors in humans, we further sought to identify in animals how pyrethroids alter the timing of puberty. Postnatal exposure to a widely used pyrethroid pesticide, cypermethrin, can accelerate pubertal timing and induce circulating levels of gonadotropins and testosterone in male mice. Our findings reveal the activation of voltage-gated calcium channels pathway in pituitary gonadotropes and testicular Leydig cells as a newly discovered mechanism of pyrethroid-induced early pubertal development in the male.

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Environmental Pyrethroids May Be Associated With Behavioral Problems in Children

MedicalResearch.com Interview with:
Professor Jean-Francois Viel
Department of Epidemiology and Public Health
University Hospital
Rennes, France

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The use of pyrethroid insecticides has increased substantially throughout the world over the past several decades, replacing organophosphate and carbamate insecticides, because of their chemical potency against many pests, their relatively low mammalian toxicity and their favorable environmental profiles. However, despite the neurotoxicity of these insecticides at high doses, the potential impact of environmental exposure to pyrethroid insecticides on child neurodevelopment has only just started to receive attention.

Using a longitudinal design (PELAGIE mother-child cohort), we were able to assess pyrethroid exposure (trough urine concentrations) both prenatally and during childhood (at 6 years of age). We showed that increased prenatal concentrations of one pyrethroid metabolite (cis-DCCA, a metabolite of permethrin, cypermethrin and cyfluthrin) were associated with internalising difficulties (children showing behaviours that are inhibited and over-controlled).

Moreover, for childhood 3-PBA (a common metabolite of up to 20 synthetic pyrethroid insecticides) concentrations, a positive association was observed with externalising difficulties (children showing behaviours that are under-controlled and having generally a more challenging temperament).

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Thyroid Hormone Disruptors Found In Household Cats and Dust

MedicalResearch.com Interview with:

Jana Weiss PhD Department of Environmental Science and Analytical Chemistry Stockholm University

Dr. Jana Weiss

Jana Weiss PhD
Department of Environmental Science and Analytical Chemistry
Stockholm University

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: In an earlier publication, we could see an association between elevated concentrations of brominated flame retardants (BFR) in the blood of cats with developed Feline hyperthyroidism, compared to healthy cats (Norrgran et al 2015, ES&T 49:5107-5014). To establish the exposure pathway we now took paired samples from healthy cats and dust from their households. We also analysed the cats food to include another major exposure pathway. In total 17 families participated. They lived in houses in the countryside or in apartments in the city. All families had kids under 12 years of age living at home, thus representing a household with typical child products. The dust was sampled from the living room, the child’s room and from the adult’s bedrooms. We could not see any difference in the composition of compounds between the rooms, but we saw that levels were in general higher in the living room compared to the other two rooms. This was expected as many products being treated with BFRs can be found in the living room.

We could see that higher levels of some  brominated flame retardants in the dust were correlated to elevated levels in the cat’s blood. Therefore, this hypothesized exposure pathways is now statistically established. We could also confirm cat food to be the major exposure pathway for naturally brominated compounds coming from the marine food web, such as6-OH-BDE47, a known thyroid hormone disruptor. Continue reading

Smokers Who Switch Completely To E-Cigs Reduce Their Exposure to Toxins

MedicalResearch.com Interview with:
Dr Lion Shahab
MA (Oxon) MSc MSc PhD CPsychol AFBPsS PGCLTHE
Senior Lecturer in Health Psychology
Department of Behavioural Science and Health
University College London
London 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: To date most studies on e-cigs have either looked at the product itself, i.e. analysed vapour/aerosol or e-liquid, or investigated its effects on animal and cell models. Only very few studies have looked at actual body-level exposure in users of e-cigarettes to evaluate their safety, and this study is the first to explore this in long-term real-life users of e-cigs.

We find that compared with people who continue to smoke conventional cigarettes, those who switch over completely to using e-cigarettes long-term (1.5 years) dramatically reduce their exposure to cancer-causing chemicals to levels observed in users of nicotine replacement products like nicotine patch or gum (which are known to be safe when used long-term).

Our results also suggest that while e-cigarettes are not only safer, the amount of nicotine they provide is not noticeably different to conventional cigarettes. This can help people to stop smoking altogether by dealing with their cravings in a safer way.

MedicalResearch.com: What should readers take away from your report?

Response: The public has been receiving very mixed signals about the safety of e-cigarettes, with some reports claiming to show that they are as harmful as smoking. These reports have been based on studies that bear little relationship to exposure of e-cigarette users in the real world.

We report the first study that has actually measured the intake of potentially harmful chemicals in e-cigarette users, and compared this with people using licensed nicotine products (e.g. nicotine patches), and cigarettes. This study should reassure smokers who are thinking of switching to an e-cigarette that if they manage to cut out cigarettes altogether, they should see a large benefit in terms of their health.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: The next step would be would be to follow smokers over a longer period of time who switch over to using e-cigarettes and measure potential harm and risks not only in relation to cancer but also lung function and cardiovascular health.

MedicalResearch.com: Is there anything else you would like to add?

Response: None of the other authors have received funding from an e-cigarette company or any organisation acting for one.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

Citation:

Shahab L, Goniewicz ML, Blount BC, Brown J, McNeill A, Alwis KU, et al. Nicotine, Carcinogen, and Toxin Exposure in Long-Term E-Cigarette and Nicotine Replacement Therapy Users: A Cross-sectional Study. Ann Intern Med. [Epub ahead of print 7 February 2017] doi: 10.7326/M16-1107

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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By Interacting with Melatonin, Insecticides Could Disrupt Circadian Rhythm

MedicalResearch.com Interview with:

Rajendram Rajnarayanan PhD Department of Pharmacology and Toxicology Assistant Professor Jacobs School of Medicine and Biomedical Sciences University of Buffalo

Dr. Rajendram Rajnarayanan

Rajendram Rajnarayanan PhD
Department of Pharmacology and Toxicology
Assistant Professor
Jacobs School of Medicine and Biomedical Sciences
University of Buffalo

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Human exposure to environmental chemicals i.e., insecticides and pesticides increases the risk of various diseases by directly interacting with proteins or signaling pathways in the endocrine or neuroendocrine system. In this study, our teamscience effort integrating big-data computation with receptor pharmacology, report for the first time that carbamate insecticides found in household and agricultural products interact with human melatonin receptors.

At UB we have generated a database, we call it Chem2Risk, which contains about four million chemicals reported to have some level of toxicity. From those, after grouping the chemicals in clusters according to their similarity, we found several with potential to mimic melatonin. Wet-lab experiments confirmed that these chemicals indeed interact with melatonin receptors and have the potential to alter melatonin signaling. Continue reading