Department of Epidemiology

Our Work

Faculty, fellows, students, and staff affiliated with Center for Children’s Environmental Health lead research across a wide spectrum of topics related to environmental health.

Breadcrumb

Our Work

Faculty, fellows, students, and staff affiliated with Center for Children’s Environmental Health lead research across a wide spectrum of topics related to environmental health.

Interventions to Reduce Chemical Exposures

We are developing effective, sustainable, and scalable interventions that reduce exposure to multiple chemicals.

We and others have shown that dietary and residential interventions can reduce exposure to pesticides, phthalates, and bisphenol A (BPA). Our team found that residential interventions reduce exposure to lead and phthalates. However, it is unclear if multimodal interventions could simultaneously reduce exposure to multiple chemicals.

Modifiable Determinants of Environmental Exposures

We study the sources and determinants of chemical exposures in pregnant women, infants, children, and adolescents.

We are enumerating the sources and determinants of environmental pollutant exposures so that individuals can modify their behavior to reduce exposure and policy makers can identify modifiable exposure sources that are amenable to regulatory interventions.

Dozens, if not hundreds of potentially toxic compounds are found in food, drinking water, breast milk, formula, consumer/personal care products, and residential dust. These include metals, phthalates, phenols, perfluoroalkyl substances (PFAS), and flame retardants. Just as infants and children are not exposed to one chemical at a time, the determinants of exposure do not occur in isolation. Infancy and early childhood are dynamic periods characterized by changes in diet, activity patterns, anatomy, physiology, and behavior. These factors influence the magnitude and opportunity for chemical exposures over the lifespan.

We are expanding our work in this area by examining infancy and early childhood exposure to the “chemical exposome” in the Hassenfeld Child Health Innovation Institute cohorts.

Molecular Epidemiology of Environmental Exposures

We study the mechanisms that environmental chemicals affect human health.

Members and affiliates of our center are using a variety of molecular technologies to study the biological pathways affected by environmental exposures. By doing this, we hope to improve causal inference, identify at-risk populations, and potentially discover pre-clinical markers of disease related to chemical exposures.

We have undertaken targeted studies to show how chemicals affect a single biological pathway and whether that biological pathway affects child health. More recently, we have begun using untargeted ‘-omics’ technologies, like DNA methylation and metabolomics, to understand the relations of a larger number of biological pathways to environmental exposures and human health. 

Health Effects of Environmental Exposures

We study if and when exposure to environmental chemicals affects childhood health.

Members of our center asks if and when environmental exposures affect the risk of disease and well-being across the lifespan.

The sperm/ova, fetus, infant, child, and adolescent may be susceptible to the effect of environmental exposures. The interplay of nutritional deficiencies, psychosocial stress, and chemical exposures during this period are risk factors for adverse early childhood growth and neurodevelopment. Much of our knowledge regarding the effect of chemical exposures on childhood health has been focused solely on the prenatal period. However, we know far less about the determinants and health effects of chemical exposures before conception and after birth.

We do our work using several prospective birth cohort studies in the US and Canada, including the HOME Study, MIREC Study, PEACE Study, and Hassenfeld Child Health Innovation Institute Studies.

Our group is enumerating the sources and determinants of chemical exposures in pregnant women and children so that individuals can modify their behavior to reduce exposure or so that policy makers can identify exposure sources that are amenable to regulatory interventions. In addition, our work has helped to quantify the role of exposure measurement error in studies of non-persistent environmental chemical exposures.

  • Braun JM, Kalkbrenner AE, Calafat AM, et al.  Variability and Predictors of Urinary Bisphenol A Concentrations During Pregnancy.  Environmental Health Perspectives. 2011;119(1):131-7.
  • Stacy SL, Eliot M, Calafat AM, Chen A, Lanphear B, Hauser R, Papandonatos GD, Sathyanarayana S, Ye X, Yolton K, Braun J. Patterns, Variability, and Predictors of Urinary Bisphenol A Concentrations during Childhood. Environmental Science & Technology. 2016.

We have conducted numerous studies quantifying the role of environmental chemicals in the etiology of birth weight, body composition, early childhood growth, breastfeeding duration, and childhood obesity, all known risk factor for cardiometabolic dysfunction. We use sophisticated statistical methods to identify potential periods of heightened susceptibility to chemical exposures.

  • Braun JM, Romano ME, Webster G, Calafat AM, Chen A, Yolton K, and Lanphear BP. Prenatal Perfluoroalkyl Substance Exposure and Child Adiposity at 8 Years of Age: The HOME Study. Obesity. 2016; 24: 231-7.
  • Shoaff J, Papandonatos GD, Calafat AM, Ye X, Chen A, Lanphear BP, Yolton K, Braun JM. Early-Life Phthalate Exposure and Adiposity at 8 Years of Age. Environmental Health Perspectives. 2017;125(9):097008. doi: 10.1289/EHP1022.

Our team has been identifying chemical risk factors for several childhood neurodevelopmental disorders, including attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and learning disabilities. We examine a wide range of potential neurotoxicants, including lead, triclosan, phthalates, and bisphenol A.

  • Braun JM, Kahn RS, Froehlich T, et al. Exposures to environmental toxicants and attention deficit hyperactivity disorder in U.S. children. Environmental Health Perspectives 2006;114:1904-9.
  • Braun JM, Kalkbrenner AE, Just AC, et al. Gestational exposure to endocrine-disrupting chemicals and reciprocal social, repetitive, and stereotypic behaviors in 4- and 5-year-old children: the HOME study. Environmental Health Perspectives 2014;122:513-20.

Humans are exposed to hundreds of environmental chemicals as a mixture across the lifespan and we have limited understanding of their effects on human health. We developed a framework to characterize questions that epidemiological studies can address regarding chemical mixtures and implemented several different methods to assess the individual and cumulative effect of chemical mixtures on children’s health.

  • Braun JM, Gennings C, Hauser R, Webster TF. What Can Epidemiological Studies Tell Us about the Impact of Chemical Mixtures on Human Health? Environmental Health Perspectives. 2016;124(1):A6-9.
  • Romano ME, Eliot MN, Zoeller RT, Hoofnagle AN, Calafat AM, Karagas MR, Yolton K, Chen A, Lanphear BP, Braun JM. Maternal urinary phthalate metabolites during pregnancy and thyroid hormone concentrations in maternal and cord sera: The HOME Study. International Journal of Hygiene and Environmental Health. 2018.

We use molecular epidemiology approaches to probe specific biological pathways or identify novel biological pathways that chemical exposures act upon. This includes endocrine pathways like thyroid and adrenal function, as well as DNA methylation and metabolomics. Our group was the first to examine the relation between prenatal perfluoroalkyl substance exposure and leukocyte DNA methylation at >450,000 CpG loci.

  • Braun JM, Chen A, Hoofnagle A, Papandonatos GD, Jackson-Browne M, Hauser R, Romano ME, Karagas MR, Yolton K, Thomas Zoeller R, Lanphear BP. Associations of early life urinary triclosan concentrations with maternal, neonatal, and child thyroid hormone levels. Hormones and Behavior. 2017.
  • Kingsley SL, Kelsey KT, Butler R, Chen A, Eliot MN, Romano ME, Houseman A, Koestler DC, Lanphear BP, Yolton K, Braun JM. Maternal serum PFOA concentration and DNA methylation in cord blood: A pilot study. Environmental Research. 2017;158:174-8.
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Joseph Braun on GoLocal

 

Braun was named one of twenty pioneers under 40 in Environmental Public health