Researchers

The MIREC Research Platform has one of the most comprehensive datasets on prenatal and post-natal exposure to multiple environmental chemicals. The scope of the data and biological specimens in the Biobank makes this research platform a significant resource for examining potential adverse health effects of exposure to environmental chemicals during pregnancy and early life of the child.

Click these links to find out more about our completed or ongoing Biobank Projects and an overview of the procedures to request access to the Biobank.

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Biobank Projects Content

These are short descriptions of the Biobank projects that have been approved so far:

1) Environmental Chemicals and Maternal-Fetal Markers of Diabetes, Obesity and Metabolic Dysfunction

Diabetes and obesity are major threats to human health with alarming increases in their prevalence worldwide. Although environmental chemicals have been implicated in the risk of diabetes, little is known about the effects of prenatal exposures on development of diabetes, obesity, and metabolic dysfunction in pregnant women and children. The objective of this study was to determine whether prenatal exposure to environmental chemicals is associated with diabetes and early life markers of obesity and metabolic dysfunction within the MIREC cohort of 1,800 mother-infant pairs from 10 sites in 6 Canadian provinces. This study examined gestational diabetes, impaired glucose tolerance and excessive maternal weight gain, and using cord blood samples, determined fetal markers of metabolic disorders (levels of leptin and adiponectin) in relation to exposure to environmental chemicals.
Lead Investigator: Linda Dodds, Dalhousie University, Halifax
Co-Investigators: Adrienne Ettinger, William Fraser, Tye Arbuckle, Mandy Fisher, Erin Keely, Maryse Bouchard, Shayne Taback, Patricia Monnier, Renée Dallaire

2) Measuring Fetal Exposure to Alcohol by Fatty Acid Ethyl Esters (FAEE)

The National Task force for Fetal Alcohol Spectrum Disorder (FASD) screening includes national experts under the auspices of The Canadian Association of Paediatric Health Centres with support from the Public Health Agency of Canada. This group is working to develop a national screening tool kit for FASD. Meconium from the MIREC Biobank was used to further validate one component of the tool kit, the meconium screening test. This biomarker identifies objectively fetuses that were heavily exposed to ethanol in utero. The MIREC samples were used to calculate the national incidence of fetal exposure to maternal heavy drinking. This will provide the first ever such national estimate in Canada, or in any other country.
Lead Investigator: Shinya Ito, The Hospital for Sick Children, Toronto
Co-Investigator: Kaitlyn Delano, PhD candidate

3) Exposure to free and conjugated forms of Bisphenol A (BPA) and Triclosan (TCS) during Pregnancy within the MIREC Study

New sensitive methods to measure free and conjugated forms of bisphenol A and triclosan in maternal urine samples were developed. The aims of this research were to measure exposure to these chemicals within the MIREC cohort by analysing 1st trimester urine samples, and to compare body burdens of these chemicals with other pregnancy cohorts and national level surveys.This research was to provide direction to the US National Children’s Study on the selection of chemicals for biomonitoring, as well as evidence for risk assessment and management of these chemicals.
Lead Investigator: Tye Arbuckle, Population Studies Division, Health Canada
Co-investigators: William Fraser, Adrienne Ettinger, Mandy Fisher, Pierre Ayotte, Alain LeBlanc, Elaine Faustman, Eric Vigoren, Michael Dellarco

4) What is the impact of prenatal exposure to multiple environmental contaminants on newborn immune system development?

Childhood asthma and allergies have been on the rise in recent decades, globally and within Canada. Although there is no clear explanation for this trend, exposure to environmental chemicals found in cookware, plastics, personal care products and some foods has been suggested as a contributing factor. This research addressed the knowledge gap in how prenatal exposure to environmental chemicals affects the fetal immune system and later risk for asthma and allergies. MIREC data were used to assess umbilical cord blood levels of immune system biomarkers and prenatal exposure to environmental chemicals. MIREC questionnaire data also were used in statistical models to control for any lifestyle or medical factors that may influence the association between prenatal exposure and immune system development.
Lead Investigator: Jillian Ashley Martin, PhD student, Dalhousie University
Supervisor: Linda Dodds, Dalhousie University
Co-investigators: Tye Arbuckle, Adrian Levy, Jean Marshall

5) Assessing time-dependent vulnerability to air pollution and multi-pollutant sector impacts on fetal development in the MIREC study cohort

Data from the MIREC Biobank were used to explore two critical issues in air pollution epidemiology: identifying periods of fetal vulnerability during which time exposure may have lifelong health impacts, and estimating exposure and health effects associated with multi-pollutant mixtures. Exposure was estimated by linking data from air pollution monitoring stations currently in place in MIREC cities to health outcomes, such as preterm birth and low birth weight, observed in the MIREC cohort. The study will address critical knowledge gaps identified by the Government of Canada to reduce air pollutant emissions in order to improve the environment and health of Canadians.
Lead Investigator: Markey Johnson, Air Health Science Division, Health Canada
Co-investigators: Hwashin Shin, Tye Arbuckle, William Fraser, Nina Dobbin, Eric Roberts, Paul English, Liu Sun, Prem Kumarathasan, Mandy Fisher, Renaud Vincent, Vanessa Beaulac

6) Seroprevalence of anti-rubella and anti-pertussis IgG antibodies in Canadian pregnant women

Antibodies are proteins produced by white blood cells to fight an infection. Red blood-cells produce different antibodies following contact with different microbes, e.g., if one gets in contact with a microbe (bacteria or virus), they will produce antibodies that fight only that microbe. When someone is vaccinated against a microbe, he/she produces the same antibodies as if he/she was infected; this is how vaccines protect against diseases. In this study, we will measure antibodies against the rubella virus and against the bacterium causing whooping cough, in pregnant women to determine their level of protection and that of their unborn babies against these diseases.
Lead Investigator: Nicolas Gilbert, Public Health Agency of Canada
Co-investigators: Brian Ward

7) Impact of maternal weight and the early life nutritional and chemical environments on infant cognitive outcomes in the MIREC pregnancy cohort

The preschool years of a child’s life are a fundamental period for brain development and maturation. During these early years, biological and environmental factors interact to modify brain development and this can impact brain function in the short and long term. Poor health of the mother during pregnancy and after birth is one factor that can impact the development of the child throughout its entire life. In particular, suboptimal maternal weight before pregnancy and inappropriate weight gain during pregnancy has been linked with impaired brain development and function throughout infancy and childhood. Additionally, fetal exposure to environmental toxicants may impact the health of the pregnancy. In particular, prenatal and early postnatal exposure to various levels of heavy metal toxicants may influence cognitive development. Further, the type and amount of feeding provided to the infant can influence its growth and development, especially the brain. Mothers who are underweight, overweight or obese may have altered breastfeeding practices and different composition of breast milk than mothers who are normal weight. Recent evidence also demonstrates that heavy metals may be transferred to the infant through breast milk, interfering with normal development. Therefore, it is important to understand how maternal health, early life nutrition, and exposure to environmental toxicants, influence child cognitive development to ensure that all children have a healthy start to life. Our study will investigate the links between maternal weight before and during pregnancy and heavy metal exposure on infant cognitive outcomes in the MIREC cohort, and determine whether early life nutrition modifies these relationships.
Lead Investigator: Kristin Connor, Carleton University
Co-investigators: Paul Villeneuve, Tye Arbuckle

8) Neurodevelopmental outcomes in young children living in areas with fluoridated versus non-fluoridated public water

Water fluoridation is a population health intervention used to control tooth decay. Recent studies suggest that exposure to fluoride in drinking water may alter thyroid function, increase blood lead levels, lower IQ, and increase the risk of developing ADHD. Still, many of the human studies include groups exposed to high levels of fluoride and they often lack a comparison group or serial fluoride biomarkers. Scientific advisory groups, including the US National Research Council, recommend additional research on fluoride toxicity, with a particular focus on children who bear a greater environmental burden. In an ongoing, NIH-funded study, we are using data from a national pregnancy cohort: Maternal Infant Research on Environmental Contaminants (MIREC), to test whether prenatal fluoride exposure is associated with child IQ and behavioural function as assessed by parent ratings for children aged 3 to 4 years. Approximately half of the children (n=275) who underwent IQ testing live in cities that add fluoride to municipal water; the other half (N=335) live in cities that do not fluoridate water. This new proposal will allow us to incorporate postnatal urinary fluoride measures from this cohort to permit assessment of potential windows of vulnerability. This would be the first adequately powered investigation utilizing both prenatal and postnatal biomarkers of fluoride exposure to examine behavioural outcomes at levels of exposure relevant to the U.S. and Canada. Results of this study will inform current controversies about the safety of water fluoridation and assist decision makers to formulate public health policies, minimize health inequities, and reduce health care costs.
Lead Investigator: Christine Till, York University
Co-investigators: Bruce Lanphear, Gina Muckle, Pierre Ayotte, E. Angeles Martinez-Mier

9) Exposure to Phenols, Phthalates and Pyrethroids in Young Children

Canadians can be exposed to phthalates, phenols such as bisphenol A and triclosan, and pyrethroid pesticides in their daily lives from diet, and/or use of personal care or consumer products. In order to assess potential health risks from these chemicals it is important that government agencies such as Health Canada have data on the exposure of the general population and especially various susceptible sub-populations such as young children. While the Canadian Health Measures Survey has provided critical biomonitoring data on urinary concentrations of these chemicals in most age groups, it does not survey children less than 3 years of age. This particular sub-population can have additional exposures due to child-specific behaviours, including mouthing, hand-to- mouth activity and crawling. This study analyzed stored urine samples collected from all children between the ages of 23 months and 3 years of age in the MIREC-CD Plus Study. Percentile distributions, arithmetic, and geometric mean urinary concentrations for each metabolite or parent compound of these chemicals were calculated and characteristics of the child and the urine collection were examined to describe the population groups with significantly different urinary concentrations. These data will make a significant contribution to Health Canada’s screening risk assessment of these chemicals.
Lead Investigator: Angelika Zidek, Health Canada
Co-investigators: Tye Arbuckle, Karelyn Davis, Mandy Fisher, Monique D’Amour

10) MIREC-ENDO (Maternal-Infant Research on Environmental Chemicals – Pubertal Timing, Endocrine and Metabolic Function) Phase 1 (a) Maternal Biomonitoring

Although about 800 chemicals are known or suspected to be capable of interfering with hormone systems, only a small fraction of these endocrine disrupting chemicals have been investigated to test for endocrine effects such as metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood. It is well recognized that the prenatal period is critical for the development of healthy children and adults. Therefore, it is especially important to have data on exposure of pregnant women to potential endocrine disrupting chemicals. In MIREC, approximately 80 chemicals were measured in 1st trimester maternal biospecimens. Since MIREC’s inception in 2008, new scientific knowledge has suggested additional chemicals should be considered for biomonitoring in our population of pregnant women, taking advantage of the stored maternal urines in the MIREC Biobank. Included among these are chemicals that have introduced to replace bisphenol A (BPA) and PBDE flame retardants, as well as chemicals used in plastics and consumer products (phthalates), and a commonly used herbicide in agriculture (glyphosate). This project will measure these new emerging chemicals in maternal urine from the 1st trimester stored in the MIREC Biobank and add to the list of chemicals that can be studied for potential health effects on the pregnancy and infant and child health within the MIREC Research Platform.
Lead Investigator: Tye Arbuckle, Health Canada
Co-investigators: Mandy Fisher, Bruce Lanphear, Susan MacPherson

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