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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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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Adding Predator Cues To Biopesticides Increases Mosquito Mortality

MedicalResearch.com Interview with:

Lin Op De Beeck, PhD Laboratory of Aquatic Ecology, Evolution and Conservation University of Leuven Leuven, Belgium

Lin Op De Beeck

Lin Op De Beeck, PhD student
Laboratory of Aquatic Ecology, Evolution and Conservation
University of Leuven
Leuven, Belgium

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

Response: Mosquitoes transmit quite a few deadly diseases, including West Nile Virus. Around the world, therefore, the fight against these insects is high on the agenda. Existing strategies for mosquito control often involve the use of chemical pesticides that harm the environment. These pesticides are increasingly less effective as well, as insects can become resistant to existing products relatively quickly. Biopesticides are a possible alternative. The most commonly used biological pesticide is the Bacillus thuringiensis israelensis (Bti) bacteria. Unfortunately, mosquitoes are already developing resistance to this pesticide as well. This means we have to keep increasing the dose of Bti to kill mosquitoes, so that this biological substance, too, is beginning to harm the environment.

Therefore we set out to find a new strategy in the fight against mosquitoes. We already knew that chemical substances emitted by the backswimmer – a natural enemy of mosquito larvae in the water – trigger a stress response in mosquitoes. This stress response, in turn, suppresses the mosquito’s immune system. What makes the use of these predator cues even more interesting for mosquito control is that scientists recently found a way to produce a synthetic version of these chemical substances. We discovered that this synthetic version triggers a stress response in the mosquitoes and impairs their immune system, just like the natural predator cues. This gave us the idea to combine these synthetic predator cues with the biological pesticide Bti.

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Acute Occupational Pesticide-Related Illness Highest in Agricultural Workers

MedicalResearch.com Interview with:
Geoffrey M. Calvert MD

Division of Surveillance, Hazard Evaluations, and Field Studies
National Institute for Occupational Safety and Health
CDC Cincinnati, Ohio

Medical Research: What is the background for this study?

Dr. Calvert: Since 1987, acute occupational pesticide-related illness and injury has been one of the conditions under surveillance by NIOSH. NIOSH supports these surveillance activities by providing cooperative agreement funding and technical support to state health departments. The SENSOR-Pesticides program is also partially funded by EPA. A total of 12 states currently participate in the SENSOR-Pesticides program.

With the 2015 publication of the Summary of Notifiable Non-Infectious Conditions and Disease Outbreaks – United States, official statistics for the occurrence of acute occupational pesticide-related illness and injury were published for the first time in the same volume of the MMWR with information on nationally notifiable infectious diseases.

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Pesticides In Fruits and Vegetables May Lower Sperm Count In Men

Jorge E. Chavarro, M.D., Sc.D. Assistant Professor of Nutrition and Epidemiology Harvard T.H. Chan School of Public Health Assistant Professor of Medicine Harvard Medical School Boston, MA 02113MedicalResearch.com Interview with:
Jorge E. Chavarro, M.D., Sc.D.
Assistant Professor of Nutrition and Epidemiology
Harvard T.H. Chan School of Public Health
Assistant Professor of Medicine
Harvard Medical School Boston, MA 02113

Medical Research: What is the background for this study?

Dr. Chavarro: Previous studies have shown that occupational exposure to pesticides is harmful to sperm production. However, whether the same is true for pesticide residues in our food, the most important source of exposure to pesticides for most people, is unclear.

Medical Research: What are the main findings?

Dr. Chavarro: Bottom line, men who consumed the greatest amounts of fruits and vegetables with large amounts of pesticide residues had significantly lower sperm counts and fewer morphologically normal sperm.

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Pesticide Exposure May Impact Development Of ADHD

MedicalResearch.com Interview with:
Jason R. Richardson MS,PhD DABT Associate Professor
Department of Environmental and Occupational Medicine
Robert Wood Johnson Medical School and
Resident Member
Environmental and Occupational Health Sciences Institute
Piscataway, NJ

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

Dr. Richardson:  Although ADHD is often though of as a genetic disorder, no single gene can explain more than a fraction of the cases. This suggests that environmental factors are likely to interact with genetic susceptibility to increase risk for ADHD. Our study reports that exposure of pregnant mice to relatively low levels of a commonly used pesticide reproduces the behavioral effects of ADHD in their offspring. Because the study was in animals, we wanted to see if there was any association in humans. Using data from the Centers for Disease Control and Prevention we found that children and adolescents with elevated levels of metabolites of these pesticides in their urine, which indicates exposure, were more than twice as likely to be diagnosed with ADHD.

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Parkinson’s disease and exposure to Pesticides

MedicalResearch.com eInterview with Dr. Emanuele Cereda

Nutrition and Dietetics Service, Fondazione IRCCS Policlinico San Matteo
Viale Golgi 19, 27100 Pavia, Italy

MedicalResearch.com: What are the main findings of the study?

Dr. Cereda: A large analysis of more than 100 studies shows that exposure to pesticides, or bug and weed killers, and solvents is likely associated with a higher risk of developing Parkinson’s disease.

MedicalResearch.com: Were any of the findings unexpected?

Dr. Cereda: In first instance I can say no as in every day clinical practice we frequently see patients reporting such exposure. Accordingly, it appears quite obvious to look at these exposures as risk factors. Unfortunately, from an epidemiologic point of view this is not enough! That’s why we did this study. Amazing rather than surprising was the fact that commonly the sources of funding in the studies we retrieved and included in meta-analysis were health or health-related institutions, private foundations (mainly Parkinosn’s disease foundations), or government or para-government companies. No study acknowledged the involvement of any chemicals manufacturer!
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