Research Projects- Occupational & Environmental Epidemiology 

The Undergraduate Research Education Program (Undergirding Potential Program: UP Program) in Environmental Health Sciences (EHS) is a collaboration among the University of Michigan (Michigan), Hampton University (Hampton), and Fisk University (Fisk) with the goal of increasing diversity in the EHS research workforce and accelerating improvements in environmental quality and public health. Faculty from Michigan’s EHS Department (School of Public Health) with robust research programs on NIEHS priority areas will mentor four undergraduate students per summer. Hampton and Fisk Universities are historically black colleges and universities (HBCUs) with developing research interests in EHS among both faculty and students. Students will be co-selected by Fisk, Hampton and Michigan UP Program leaders (Drs O’Neill, Charles, Heyliger and Martin) and matched with faculty mentors. These faculty will also explore future research and training collaborations in EHS across the institutions. Selected students must have completed two years in an EHS-relevant baccalaureate degree program, in biology, chemistry, environmental sciences, physics, engineering, or mathematics. Trainees will have summer research experiences at Michigan with continued communications throughout the year. Topics for research projects include epigenetic and genomic impacts of exposures, and human health aspects of environmental exposures (including cancer and other outcomes associated with pesticides, heavy metals, components of plastics, air pollutants, and climate-related exposures). The partnership between Michigan and the HBCUs will increase the HBCU student’s interest in EHS as a career and achieve the long-term goal of diversifying the EHS workforce by providing `early pipeline’ opportunities to underrepresented students in EHS. Students will receive both hands-on research experiences, education, and skills needed to pursue graduate school and careers in EHS. Participants will receive up to two summers of training and education, including a full-time summer mentored research experience in EHS at Michigan, training in responsible conduct of research, educational activities, lectures, and group collaboration. They will benefit from coordination with several existing undergraduate internship programs at Michigan, and the EHS Environmental Toxicology and Epidemiology Program (ETEP) T32 training grant for pre- and post- doctoral students, now in its 33rd year of NIEHS support. Trainees will have access to graduate students, including those from under-represented backgrounds, with first-hand knowledge of the process and career options. The Michigan-Hampton-Fisk UP Program R25 is structured to specifically meet the goals of: (1) diversifying the EHS workforce and (2) advancing the NIEHS mission, and (3) enriching EHS scholarship and training at all three universities.

The Michigan Farmworker Project conducted by Michigan Public Health researchers found that farmworkers (migrant, seasonal, and H-2A)—considered “essential workers” – face challenging working and living conditions that are critical to address during the COVID-19 pandemic. Efforts to limit COVID-19 risks in this population require an evidence-based, multifactorial approach that involves workers, employees, and stake-holders. In a policy brief, the researchers recommend that enforcement actions be taken to ensure compliance with COVID-19 protection and mitigation guidelines instead of reliance on self-compliance.

Introduction Toxic exposure, combined with poor working conditions, poor nutrition, poverty, maternal stress, and other key social and economic factors, contributes to the loss of developmental potential in young children. Although fungicide use is growing exponentially in the United States and globally, a significant gap exists in scientific knowledge about the neuro developmental toxicity of fungicides, and their interaction with critical social and structural determinants of health. Ethylenebisdithiocarbamates are commonly-used fungicides in floriculture and horticulture, which metabolizes ethylenethiourea (ETU). Research indicates that prenatal ETU exposure may cause maternal and neonatal thyroid dysfunction, potentially leading to adverse pregnancy outcomes and impaired neurodevelopment. This presentation will describe the SEMILLA study, a community-engaged cohort study, building on years of previous work, which assesses environmental and occupational toxic exposures among women workers in a major flower-growing region of Ecuador.

Methods SEMILLA follows pregnant workers and their infants up to 18 months of age, incorporating prenatal measures of ETU exposure. Methods include obtaining monthly prenatal urine samples and maternal and neonatal blood samples to assess thyroid hormone levels. At each visit throughout the study, we collect detailed data on key social and structural factors including working conditions, environmental exposures in home and work environments, stress, social support, maternal health and lifestyle, socio-economic and demographic factors. We will administer highly sensitive tests to assess neurodevelopment and visual function as well as growth and nutritional status in enrolled infants.

Results and Discussion SEMILLA will contribute key data to inform our understanding of how toxic exposure, combined with key social and structural factors, impact child development; data which is critical for developing and initiating appropriate and sustainable interventions in affected communities that promote optimal child health and development, reduce environmentally-associated community exposures, and improve worker health policies. We will discuss important strengths and challenges in the implementation of SEMILLA.

Project Summary An estimated 1 in 6 children in the U.S. and over 200 million children in the developing world are not reaching their full developmental potential. Although fungicide use is growing exponentially in the United States and globally, a significant gap exists in scientific knowledge about the neurodevelopmental toxicity of fungicides. Ethylenebisdithiocarbamates, or EBDCs, are commonly-used fungicides in agricultural production as well as in floriculture and horticulture. EBDCs are metabolized into a more toxic carcinogenic and teratogenic compound, ethylenethiourea (ETU), which has been associated with decreased serum thyroxine levels, increased thyroid stimulation hormone levels, and thyroid gland disorders. Although research indicates that prenatal ETU exposure may cause maternal and neonatal thyroid dysfunction, potentially leading to adverse outcomes including pregnancy loss, preterm delivery, intrauterine growth restriction, disruptions in fetal central nervous system and brain development and impaired cognitive and motor function, no epidemiological studies to date has evaluated the effects of prenatal exposure to ETU on newborn thyroid function or the subsequent neurobehavioral development of infants. This study proposes to follow pregnant women and their infants, incorporating prenatal urinary biomarkers of ETU exposure, survey data of environmental ETU exposure and key social and economic factors, and sensitive growth and neurobehavioral developmental measures. We hypothesize that higher maternal urinary ETU levels during pregnancy will be associated with delayed growth measures and lower cognitive, visual, and psychomotor developmental assessment scores at birth, 6, 12, and 18 months of age and that this association will be mediated through an impact on newborn thyroid function. The proposed research takes advantage of a unique opportunity to investigate this question in a highly exposed population in Ecuador. We will enroll 420 pregnant women at 10-12 weeks gestation and follow them through pregnancy up to 18 months post-partum. We will obtain monthly prenatal urine samples. We will obtain neonatal blood samples to assess thyroid hormone levels at birth. We will administer highly sensitive tests (BSID-III, Teller cards) that will assess cognitive, motor, language, and social-behavioral development, and visual function in infants. Infants will also be measured for growth and nutritional status. At each visit throughout the study, data will be collected on working conditions, stress, environmental exposures in home and work environments, social support, maternal health and lifestyle factors, socio-economic and demographic factors. We will quantify levels of prenatal ETU exposure and will analyze levels by trimester. We will assess associations between prenatal urinary ETU metabolite levels and infant developmental outcomes and will run a multivariate path analysis to test for a mediating effect of newborn thyroid dysfunction on this association. This study will further scientific understanding of the developmental consequences of exposure to fungicides, which have become the most commonly used pesticides in agricultural industry in the U.S. and globally.