USC Researchers Present the Latest on Environmental Health in Santiago, Chile at 2024 International Society for Environment Epidemiology Conference

The 36th Annual Conference of the International Society for Environment Epidemiology was hosted in Santiago Chile, from August 25-28, 2024. This year’s theme was ‘Addressing challenges in environmental health, justice, and development.’ Researchers from the Division of Environment Health in the Department of Population and Public Health Sciences from the Keck School of Medicine presented their latest research to an international audience. Read below to learn more about our investigator’s participation at the conference.

Emily Beglarian

4th year PhD Student in Epidemiology

Title: Exposure to Perfluoroalkyl Substances is Associated with Longitudinal Changes in Adiposity in a Hispanic Adolescent Cohort

Description: Per- and polyfluoroalkyl substances (PFAS) have shown associations with levels of fat mass in humans. In our study, we found that four PFAS were associated with changes in fat mass in Hispanic adolescents followed over time, which may impact fat mass over the life span and increase risk of certain diseases.

Brittney Baumert

Postdoctoral Research Fellow

Title: PFHpA alters lipid metabolism and increases the risk of MASLD in youth

Description: We integrated human epidemiological data with in vitro experimental findings to evaluate the relationship of PFHpA concentration and MASLD. In our analysis of the Teen-LABS cohort, we observed that each doubling of PFHpA levels was linked to an 81% increase in MASLD risk. Integrative analysis revealed overlapping dysregulated pathways in both human and spheroid models, especially those related to innate immunity, inflammation, and lipid metabolism.

Liz Costello

Postdoctoral Research Associate

Title: Associations Between PFAS and Longitudinal Changes in Insulin Sensitivity in Adolescents

Description: In this analysis, we looked at whether or not certain replacement PFAS chemicals (PFHpA, PFHpS, and PFPeS) might affect adolescents’ blood sugar or insulin. We found that, in males during early puberty, higher blood levels of PFHpA may be linked to insulin resistance. Insulin resistance can increase the risk for type 2 diabetes.

Shohreh Farzan, PhD

Associate Professor of Population and Public Health Sciences

Oral Presentation

Title: Children’s Cardiovascular Health in a Changing Climate: Associations of Prenatal Heat Stress and Community Nature-Based Adaptation Features with Child Blood Pressure

Description: We found that exposure to prenatal heat stress was associated with greater child blood pressure at age 3 years. However, greater prenatal exposure to nature-based features, including tree canopy cover and park area, was related to lower child blood pressure. Our results begin to suggest that heat stress may be an underrecognized threat to child cardiovascular health, but that increasing nature-based features could help mitigate some of these climate-related health effects.

Erika Garcia, PhD, MPH

Assistant Professor of Population and Public Health Sciences

Oral Presentation

Title: Disparities of Electronic Vehicle Adoption in California and Urban Gentrification: A Community Dialogue Informed Approach

Description: Our larger study examines disparities in electric vehicle (EV) adoption across California and we heard concerns about gentrification from our community advisory board. As a result, in this analysis we looked at whether EV adoption trends were different by level of gentrification in the San Francisco and Los Angeles areas. We found that disadvantaged communities experienced inequity in EV adoption, and the biggest gap was in the more gentrified neighborhoods, which threatens equitable distribution of potential health co-benefits.

Jesse Goodrich, PhD

Assistant Professor of Population and Public Health Sciences

Oral Presentation

Title: “Beyond a single factor: Cutting-Edge Approaches in Environmental Mixtures and Omics Research”

Description: Recent advances in technology now allow scientists to measure hundreds of thousands of biologically relevant molecular factors that can provide information about how environmental factors can cause disease. However, analysis methods for incorporating environmental factors with this type of data are limited. This presentation laid out a new framework for analyzing this type of data, and used the framework to identify biological mechanisms such as inflammation that link exposure to mercury during pregnancy with risk of liver disease in children.

Hailey Hampson

Postdoctoral Scholar

Title: A Per- and Polyfluoroalkyl Substance Mixture Association with Human Gut Microbiota: Novel Bayesian Hierarchical Zero-Inflated Negative Binomial Regression with G-Computation

Description: Our research examined if blood levels of environmental chemicals called PFAS are associated with alterations in the gut microbiome in a multiethnic cohort of young adults at high risk of development metabolic diseases. We found that exposure to a mixture of PFAS chemicals was associated with changes in gut bacteria that have previously been linked to metabolic diseases.

Roxana Khalili

Postdoctoral Scholar

Oral Presentation

Title: Climate Vulnerability Modifies Fetal Growth with Heat Stress and Wildfire Smoke Exposure during Preconception and Pregnancy

Description: Climate-related wildfire smoke and heat stress exposures during preconception and pregnancy were associated with length of gestation and adverse birth outcomes including small-for-gestational age, low birthweight and Fenton growth z-scores in the MADRES cohort. This is one of the first studies to show that living in more climate vulnerable neighborhoods significantly increases risks associated with heat and wildfires, suggesting that increasing adaptation capacity of communities may strengthen climate change resilience.

Sherlock Li

Postdoctoral Scholar

Oral Presentation

Title: Coupling observational study with computational toxicology to elucidate the relationships and potential mechanisms of per-and polyfluoroalkyl substances and sleep

Description: We found that PFAS (forever chemicals) were associated with reduced sleep duration and worse quality of sleep in young adults. We identified several immune system-related proteins that could explain these associations.

Zhenjian Li

Postdoctoral Scholar

Oral Presentation

Title: Identifying metabolic mediators between concentration of p,p’-DDE in visceral adipose tissue and weight loss in adolescents undergoing bariatric surgery

Description: Metabolic changes could attenuate the efficacy of bariatric surgery in achieving sustained weight loss. Notably, plasma methylbutyroyl-carnitine was found to be a potential mediator of the association of DDE concentrations with BMI and waist circumference changes after bariatric surgery. The findings enhance our understanding of environmental obesogens and their impact on metabolic pathways.

Shudi Pan

4th year PhD Student in Epidemiology

Oral Presentation

Title: Metabolic signatures linking Lipophilic Persistent Organic Pollutant Mixtures to Blood Pressure Five Years after Bariatric Surgery among Adolescents

Description: We explored the relationship between POPs and high blood pressure in obese teenagers. For teenagers who opted for surgery to help them lose weight, we studied the effects of these chemicals on blood pressure changes in this population and used small molecules in our bodies called metabolites to understand the biological mechanisms. We want to help teenagers recognize potential risks so they can lead healthier and longer lives. Additionally, our research will provide valuable insights into the complex molecular pathways that drive high blood pressure in teenagers.

Anmol Pardeshi

4th year PhD Student in Epidemiology

Title: Environmental exposures and residential mobility among Hispanic and non-Hispanic White families in California

Description: here we tried to explore the disparities in pollution across different racial/ethnic categories which might help explain disease disparities in childhood leukemia. Both Hispanics and Non-Hispanic Whites children moved to homes within less polluted vicinity as they grew up. But the most significant finding was that this change in pollution, based on the move to cleaner area, was stronger for Non-Hispanic Whites than Hispanics – meaning Hispanics were still living in relatively more polluted areas and lesser green spaces, which might explain why incidence rates are higher in that group. Explained differently, Non-Hispanic Whites moved to non-polluted areas coupled with more green spaces.

Jaime Reyes Sanchez

4th year PhD Student in Epidemiology

Oral presentation

Title: Robustness of effect modification estimates from two-stage multi-location designs to unmeasured covariates: A simulation study

Description: We created hypothetical data on a variable (let’s call it fake air conditioning) that prevented heat-related mortality (also fake). Then we applied statistical methods that are commonly used to evaluate the protective effect of (real) air conditioning on (real) heat-related mortality. These methods were able to recover the protective effect we simulated, but not always. That is, we found these methods have some weaknesses, mainly related to whether researchers include additional relevant variables (such as income) in their statistical models.

Caleb Schimke

3^rd year PhD Student in Epidemiology

Title: Efficiency of case-crossover vs time series designs for extreme heat exposures

Description: We did a simulation study comparing two popular statistical methods to estimate how many people are expected to die on extremely hot days. We simulated mortality based on observed Los Angeles County data and defined extreme heat days as anywhere between the top 20% to the top 1% hottest days. When we fit the two models to the simulated data, we discovered that the time-stratified case-crossover method had worse statistical efficiency compared to Poisson time series, and this difference was exaggerated at rarer exposures.

Himal Suthar

3^rd year PhD Student in Epidemiology

Title: Exploring Serum Bioactive Lipids as Biomarkers of PFAS Exposure in Pregnant Women Across Three Environmental influences on Child Health Outcomes (ECHO) Cohorts

Description: We analyzed the associations between 12 types of PFAS, in pairs and as mixtures, and 50 bioactive lipids in blood plasma in pregnant participants across three ECHO Cohort Study Sites. When researchers looked at data from different study sites, they found that higher levels of PFAS in blood were often linked with higher levels of certain bioactive lipids. We also noticed differences in the distribution of bioactive lipid compounds between individual study sites, possibly driven by variations in the genetic makeup and sociodemographic characteristics of the populations or differences in environmental exposures due to diet. These findings encourage researchers to prioritize the study of PFAS and bioactive lipids pairs in future testing in addition to individually studying the effect of different types of PFAS. Additionally, this study highlights the importance of regulating the 12 types of PFAS observed.