Breaking News! |
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One of our papers recently received an honorable mention for Best Environmental Epidemiology Paper of the Year by the International Society for Environmental Epidemiology (ISEE). The paper suggests that prenatal exposure to insecticides used for indoor residual spraying may be associated with altered child neurodevelopment. The award was presented to Drs. Chevrier, Eskenazi and Bornman at the ISEE conference held August 25-28, 2019 in Utrecht, The Netherlands.
Citation: Eskenazi B, An S, Rauch SA, Coker ES, Maphula A, Obida M, Crause M, Kogut KR, Bornman R, Chevrier J. Prenatal exposure to DDT and pyrethroids for malaria control and child neurodevelopment: The VHEMBE cohort, South Africa. Environ Health Perspect, 2018; 126(4): 047004. |
We have openings for full-time Research Assistant, Research Associate and Postdoc positions to work on some of the research described below.
We just received an R01 grant from the U.S. National Institute of Environmental Health Sciences to study the environmental determinants of the obesity epidemic and premature pubertal onset in South Africa.
Research
Human populations around the world are exposed to a wide range of pollutants, some recently emerging, while others have been banned for decades but still linger in the environment. The burden of disease associated with exposure to these chemicals is substantial. Globally, the World Health Organization estimates that exposure to environmental pollutants is responsible for a larger disease burden than all cancers combined. In Canada, exposure to environmental contaminants generates annual health care costs ranging between $3.4 and $9.1 billion and recent studies estimate societal costs are $175 billion annually in Europe. These estimates consider only a fraction of the more than 23,000 substances that are used on a commercial scale, most of which have not been evaluated for human health effects. Of particular concern is the impact of environmental chemicals on developing children, which are at greater risk of permanent adverse health effects than adults.
Research conducted by Dr. Chevrier's group addresses these concerns and aims to identify, understand and reduce risks associated with exposure to environmental chemicals in children and other vulnerable populations locally and globally.
To this end, Dr. Chevrier collaborates with multiple groups on research taking place in North America, Asia and Africa, including:
Inquiries from prospective students or potential collaborators may be made by contacting Dr. Chevrier by email or through the contact form on this website.
Research conducted by Dr. Chevrier's group addresses these concerns and aims to identify, understand and reduce risks associated with exposure to environmental chemicals in children and other vulnerable populations locally and globally.
To this end, Dr. Chevrier collaborates with multiple groups on research taking place in North America, Asia and Africa, including:
- The VHEMBE Program
- The Responsible Replacement Study
- The BFR Study
- The CHAMACOS Study
- The Cookstove Intervention Trial
- Causal Inference and Epidemiological Methods
Inquiries from prospective students or potential collaborators may be made by contacting Dr. Chevrier by email or through the contact form on this website.
The VHEMBE Program
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The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a research, teaching and advisory program that aims to identify, understand and manage environmental determinants of maternal and child health in rural South Africa. The VHEMBE Project comprises a collection of studies based on a birth cohort of 752 South African women-child pairs. At this time, our work focuses primarily on the effects of environmental contaminants such as public health insecticides used for Indoor Residual Spraying and air pollution on:
The VHEMBE Program also aims to identify the main sources of exposure to environmental contaminants as well as interventions that could minimize exposure. Studies comprising the Program are funded by the Canadian Institutes of Health Research and the U.S. National Institute of Environmental Health Sciences.
- Perinatal outcomes (premature birth, low birth weight, intrauterine growth retardation)
- Child growth, endocrine function, immune function, respiratory health, obesity, neurobehaviour, and pubertal development
- Maternal health and female fertility
The VHEMBE Program also aims to identify the main sources of exposure to environmental contaminants as well as interventions that could minimize exposure. Studies comprising the Program are funded by the Canadian Institutes of Health Research and the U.S. National Institute of Environmental Health Sciences.
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"The Program is located in the Vhembe district of Limpopo Province, South Africa, a rural area situated close to the Zimbabwe and Mozambique borders. It is the very first cohort study to investigate impacts of exposure to IRS insecticides and air pollution on child health in Africa." Dr. Chevrier is the Principal Investigator of the VHEMBE Program. Brenda Eskenazi, from the University of California, Berkeley, was Principal Investigator of the first phase of the cohort (follow up from birth to age 2). Dr. Riana Bornman, from the University of Pretoria, is the local Principal Investigator. |
The Responsible Replacement Study
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As part of our everyday lives, we are exposed to a wide variety of chemicals, several of which may interfere with the endocrine system. As chemicals are banned or withdrawn from the market due to their potential to affect human health, they are often replaced by new compounds with similar properties and unknown health effects. The responsible replacement study aims to determine to what extent populations in different stages of economic development are exposed to these new chemicals, what their health effects may be and how current national and international regulations and policies may be modified to ensure that safe alternatives are selected.
Chemicals of interest include:
As part of the human component of the study, we will determine the concentration of these chemicals in food, water and breast milk from 600 women living in Canada (Montreal) and South Africa (Pretoria and Vhembe) and evaluate associations with fetal and early childhood development. Dr. Chevrier is co-Principal Investigator of the study; Dr. Barbara Hales is Principal Investigator. Investigators of this Canadian Institutes of Health Research-funded study also include Drs. Cindy Goodyer, Bernard Robaire
and Riana Bornman. |
"The Responsible Replacement study is an international consortium that includes collaborators from academia, government and civil society in Canada, Europe, the United States and South Africa."
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The Brominated Flame Retardants (BFR) Study
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Brominated Flame Retardants (BFRs) are persistent organic chemicals used in a variety of products including furniture, electronics and construction materials to slow down their burning rates in fires. Because BFRs are not chemically bound to products, they easily leach out and, as a result, the vast majority of Canadians have detectable levels of these chemicals in their tissues. BFRs are very stable and accumulate in the human body. Studies suggest that BFRs may adversely affect the reproductive system.
The human component of the BFR study aims to determine whether exposure to polybrominated diphenyl ethers (PBDEs), a type of BFR, is related to:
The human component of the BFR study aims to determine whether exposure to polybrominated diphenyl ethers (PBDEs), a type of BFR, is related to:
- Increased risks of infertility in men and women
- Abnormalities in boy's reproductive system (cryptorchidism/undescended testes)
- Regulatory and policy implications related to BFR exposure and impacts on reproduction
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"The BFR study is situated at the Research Institute of the McGill University Health Centre (RI-MUHC) in Montreal, Canada." Dr. Cindy Goodyer is the study's Principal Investigator for human health effects. Dr. Chevrier is a co-investigator and acts as environmental health expert and epidemiologist/biostatistician. The study, funded by the Canadian Institutes of Health Research, also includes in vitro and animal components led by Drs. Barbara Hales and Bernard Robaire |
The CHAMACOS Study |
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The Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) is a birth cohort study of 601 mother-child pairs which has been investigating environmental exposures and child development since 1999. Exposures of interest have included pesticides, metals (manganese), plastic components and metal food container liners (bisphenol A), flame retardants (PBDEs) and other persistent organic chemicals. Health impacts studied include:
The study also aims to investigate toxicological mechanisms of actions by conducting epigenetic and functional genomic studies, and to identify determinants and sources of exposure to environmental chemicals to inform the development of strategies to reduce exposure.
"The CHAMACOS study is located in California's Salinas Valley, a heavily farmed area where large amounts of pesticides are used each year."
The Principal Investigator of the CHAMACOS study is Dr. Brenda Eskenazi from the University of California, Berkeley. Dr. Chevrier is co-investigator on this study and acts as consultant in epidemiological methods and biostatistics. The study is funded by the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences
- Birth and perinatal outcomes
- Endocrine function (thyroid hormone, estrogen, testosterone, leptin, adiponectin)
- Growth
- Neurodevelopment
- Puberty onset
The study also aims to investigate toxicological mechanisms of actions by conducting epigenetic and functional genomic studies, and to identify determinants and sources of exposure to environmental chemicals to inform the development of strategies to reduce exposure.
"The CHAMACOS study is located in California's Salinas Valley, a heavily farmed area where large amounts of pesticides are used each year."
The Principal Investigator of the CHAMACOS study is Dr. Brenda Eskenazi from the University of California, Berkeley. Dr. Chevrier is co-investigator on this study and acts as consultant in epidemiological methods and biostatistics. The study is funded by the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences
The Cookstove Intervention Trial |
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Billions of people cook and heat their homes by using highly polluting solid fuel stoves that adversely impact human health and the environment. This project aims to evaluate the effect of using low polluting stoves on cardiovascular outcomes in 200 women residing in the Tibetan plateau in China. Since people using solid fuel stoves generally reside in rural agricultural areas, they are often subjected to high exposure to pesticides. This study is the first to evaluate the combined effect of exposure to household air pollution and pesticides on cardiovascular health.
"This project is located in the Sichuan province in the Southwestern area of China, where most people use solid fuel stoves indoors." The principal investigator of the cookstove intervention trial is Dr. Jill Baumgartner at McGill. Dr. Chevrier is co-investigator on the pesticide component of the study together with Dr. Mark Goldberg. |
Causal Inference and Epidemiological Methods
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Under some circumstances, traditional statistical methods will generate biased estimates when investigating relations between exposure and health outcomes. These include situations of time-varying confounding affected by prior exposure, selection bias and competing risks (i.e. death by a cause other than the one under study), to name a few. Other challenges include the difficulty posed by the fact that human populations are exposed to multiple chemicals which may be correlated and interact, hampering our ability to determine their individual health effects.
Dr. Chevrier applies and adapts causal inference methods, such a the g-estimation of accelerated failure-time models, the parametric g-formula and marginal structural models with inverse probability weighting in an attempt to address these and other methodological challenges. Recently, his research has focused on the healthy worker survivor effect, a pervasive bias in occupational epidemiology.
Dr. Chevrier applies and adapts causal inference methods, such a the g-estimation of accelerated failure-time models, the parametric g-formula and marginal structural models with inverse probability weighting in an attempt to address these and other methodological challenges. Recently, his research has focused on the healthy worker survivor effect, a pervasive bias in occupational epidemiology.