USC Environmental Health Centers

Current news, events and research projects of the Environmental Health Centers based at USC

January 27, 2022

RESEARCH ROUNDUP: Recent research from Environmental Health faculty

USC Environmental Health

Recent publications from Division of Environmental Health researchers from our associated Centers

Urinary metabolic biomarkers of diet quality in European children are associated with metabolic health

Published online January 25, 2022

“Urinary metabolic profiling is a promising, powerful tool for assessing food intake and can help us understand metabolic alterations in people in response to their diet quality,” explains Nikos Stratakis, who was a Postdoctoral Researcher at Keck School of Medicine of USC, Los Angeles, US, at the time the study was carried out, and is now a Postdoctoral Fellow at ISGlobal, Barcelona.

Read more about the research in this press release by eLife journal here.

Photo credits: Trang Doan, Magda Ehlers, Ruslan Khmelevsky, Becerra Govea

Abstract. Urinary metabolic profiling is a promising powerful tool to reflect dietary intake and can help understand metabolic alterations in response to diet quality. Here, we used 1H NMR spectroscopy in a multicountry study in European children (1147 children from 6 different cohorts) and identified a common panel of 4 urinary metabolites (hippurate, N-methylnicotinic acid, urea, and sucrose) that was predictive of Mediterranean diet adherence (KIDMED) and ultra-processed food consumption and also had higher capacity in discriminating children’s diet quality than that of established sociodemographic determinants. Further, we showed that the identified metabolite panel also reflected the associations of these diet quality indicators with C-peptide, a stable and accurate marker of insulin resistance and future risk of metabolic disease. This methodology enables objective assessment of dietary patterns in European child populations, complementary to traditional questionary methods, and can be used in future studies to evaluate diet quality. Moreover, this knowledge can provide mechanistic evidence of common biological pathways that characterize healthy and unhealthy dietary patterns, and diet-related molecular alterations that could associate to metabolic disease.

Citation. Strakakis et al., Urinary metabolic biomarkers of diet quality in European children are associated with metabolic health, eLife 2022;11:e71332 DOI: 10.7554/eLife.71332

Study authors from USC include: Leda Chatzi (senior author), Yinqi Zhao, and David Conti.

Ambient air pollution and COVID-19 incidence during four 2020–2021 case surges

Published online January 19, 2022

Photo credits: Atypeek Dgn, Maria Borisenko

Background. Air pollution exposure may make people more vulnerable to COVID-19 infection. However, previous studies in this area mostly focused on infection before May 2020 and long-term exposure.

Objective. To assess both long-term and short-term exposure to air pollution and COVID-19 incidence across four case surges from 03/1/2020 to 02/28/2021.

Methods. The cohort included 4.6 million members from a large integrated health care system in southern California with comprehensive electronic medical records (EMR). COVID-19 cases were identified from EMR. Incidence of COVID-19 was computed at the census tract-level among members. Prior 1-month and 1-year averaged air pollutant levels (PM2.5, NO2, and O3) at the census tract-level were estimated based on hourly and daily air quality data. Data analyses were conducted by each wave: 3/1/2020–5/31/2020, 6/1/202–9/30/2020, 10/1/2020–12/31/2020, and 1/1/2021–2/28/2021 and pooled across waves using meta-analysis. Generalized linear mixed effects models with Poisson distribution and spatial autocorrelation were used with adjustment for meteorological factors and census tract-level social and health characteristics. Results were expressed as relative risk (RR) per 1 standard deviation.

Results. The cohort included 446,440 COVID-19 cases covering 4609 census tracts. The pooled RRs (95% CI) of COVID-19 incidence associated with 1-year exposures to PM2.5, NO2, and O3 were 1.11 (1.04, 1.18) per 2.3 μg/m3,1.09 (1.02, 1.17) per 3.2 ppb, and 1.06 (1.00, 1.12) per 5.5 ppb respectively. The corresponding RRs (95% CI) associated with prior 1-month exposures were 1.11 (1.03, 1.20) per 5.2 μg/m3 for PM2.5, 1.09 (1.01, 1.17) per 6.0 ppb for NO2 and 0.96 (0.85, 1.08) per 12.0 ppb for O3.

Conclusion. Long-term PM2.5 and NO2 exposures were associated with increased risk of COVID-19 incidence across all case surges before February 2021. Short-term PM2.5 and NO2 exposures were also associated. Our findings suggest that air pollution may play a role in increasing the risk of COVID-19 infection.

Citation. Margo A. Sidell, Zhanghua Chen, Brian Z. Huang, Ting Chow, Sandrah P. Eckel, Mayra P. Martinez, Fred Lurmann, Duncan C. Thomas, Frank D. Gilliland, Anny H. Xiang, Ambient air pollution and COVID-19 incidence during four 2020–2021 case surges, Environmental Research, Volume 208, 2022, 112758, 

Funding. This study was supported by the National Institute of Environmental Health Sciences (3R01ES029963-01 to AHX and ZC) at the National Institutes of Health, and the Keck School of Medicine Department of Preventive Medicine COVID-19 Pandemic Research Center (CPRC) at the University of Southern California. The funding agencies had no role in the design or conduct of the study; in the analysis or interpretation of the data; or in the preparation, review, or approval of the manuscript.

Secondhand nicotine vaping at home and respiratory symptoms in young adults

Published online January 10, 2022

Photo credit: Ruslan Alekso

Rationale. Despite high prevalence of e-cigarette use (vaping), little is currently known regarding the health effects of secondhand nicotine vape exposure.

Objective. To investigate whether exposure to secondhand nicotine vape exposure is associated with adverse respiratory health symptoms among young adults.

Method. We investigated the effect of secondhand nicotine vape exposure on annually reported wheeze, bronchitic symptoms and shortness of breath in the prospective Southern California Children Health Study cohort. Data were collected from study participants (n=2097) with repeated annual surveys from 2014 (average age: 17.3 years) to 2019 (average age: 21.9). We used mixed effect logistic regression to evaluate the association between secondhand nicotine vape and respiratory symptoms after controlling for relevant confounders.

Results. Prevalence of secondhand nicotine vape increased from 11.7% to 15.6% during the study period in this population. Prevalence of wheeze, bronchitic symptoms and shortness of breath ranged from 12.3% to 14.9%, 19.4% to 26.0% and 16.5% to 18.1%, respectively, during the study period. Associations of secondhand nicotine vape exposure with bronchitic symptoms (OR 1.40, 95% CI 1.06 to 1.84) and shortness of breath (OR 1.53, 95% CI 1.06 to 2.21) were observed after controlling for vaping, active and passive exposure to tobacco or cannabis, and demographic characteristics (age, gender, race/ethnicity and parental education). Stronger associations were observed when analysis was restricted to participants who were neither smokers nor vapers. There were no associations with wheezing after adjustment for confounders.

Conclusion. Secondhand nicotine vape exposure was associated with increased risk of bronchitic symptoms and shortness of breath among young adults.

Related editorial: Beware, vaping e-cigarettes around children is adversely impacting their lung health

Citation. Talat Islam, Jessica Braymiller, Sandrah P Eckel, Feifei Liu, Alayna P Tackett, Meghan E Rebuli, Jessica Barrington-Trimis, Rob McConnell. Secondhand nicotine vaping at home and respiratory symptoms in young adults.Thorax Published Online First: 10 January 2022. doi: 10.1136/thoraxjnl-2021-217041

Funding:  The study was supported by National Institutes of Health (grants U54CA180905, R21HD084812, P30ES007048 and 5P30CA014089).

Arsenic exposure from drinking water and endothelial dysfunction in Bangladeshi adolescents

Published online January 8, 2022\

Photo credit: Meir Roth

Abstract: Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, with ∼80% of CVD-related deaths occurring in low- and middle-income countries. Growing evidence suggests that chronic arsenic exposure may contribute to CVD through its effect on endothelial function in adults. However, few studies have examined the influence of arsenic exposure on cardiovascular health in children and adolescents. To examine arsenic's relation to preclinical markers of endothelial dysfunction, we enrolled 200 adolescent children (ages 15–19 years; median 17) of adult participants in the Health Effects of Arsenic Longitudinal Study (HEALS), in Araihazar, Bangladesh. Participants' arsenic exposure was determined by recall of lifetime well usage for drinking water. As part of HEALS, wells were color-coded to indicate arsenic level (<10 μg/L, 10–50 μg/L, >50 μg/L). Endothelial function was measured by recording fingertip arterial pulsatile volume change and reactive hyperemia index (RHI) score, an independent CVD risk factor, was calculated from these measurements. In linear regression models adjusted for participant's sex, age, education, maternal education, land ownership and body weight, individuals who reported always drinking water from wells with >50 μg/L arsenic had a 11.75% lower level of RHI (95% CI: −21.26, −1.09, p = 0.03), as compared to participants who drank exclusively from wells with ≤50 μg/L arsenic. Sex-stratified analyses suggest that these associations were stronger in female participants. As compared to individuals who drank exclusively from wells with ≤50 μg/L arsenic, the use of wells with >50 μg/L arsenic was associated with 14.36% lower RHI (95% CI: −25.69, −1.29, p = 0.03) in females, as compared to 5.35% lower RHI (95% CI: −22.28, 15.37, p = 0.58) in males for the same comparison. Our results suggest that chronic arsenic exposure may be related to endothelial dysfunction in adolescents, especially among females. Further work is needed to confirm these findings and examine whether these changes may increase risk of later adverse cardiovascular health events.

Citation: Shohreh F. Farzan, et al, Arsenic exposure from drinking water and endothelial dysfunction in Bangladeshi adolescents, Environmental Research, Volume 208, 2022, 112697,

Funding: This work was supported by the National Institutes of Health R00ES024144R24ES028532P30ES027792, and U2RTW010122.

Moving beyond medication: Assessment and interventions on environmental and social determinants are needed to reduce severe asthma

Published online December 13, 2021

Editorial by Erika Garcia and Frank Gilliland featured in the Journal of Allergy and Clinical Immunology

Asthma remains the most common chronic lung disease in children, significantly affecting children and their families and contributing to unacceptable mortality. The majority of children with asthma have mild or moderate disease and respond to treatment with medications and appropriate environmental interventions. Children with more severe disease that requires hospitalization or treatment with systemic corticosteroids and children who have uncontrolled asthma symptoms present a clinical and public health challenge as they are at increased risk for short-term and lifelong adverse health outcomes. The reasons for severe and uncontrolled asthma include lack of treatment, difficult-to-treat asthma, and refractory asthma.1 Severe asthma also includes asthma for which control is maintained only with the highest level of recommended treatment.1

Click here to read the full editorial

Citation: Erika Garcia, Frank Gilliland, Moving beyond medication: Assessment and interventions on environmental and social determinants are needed to reduce severe asthma, Journal of Allergy and Clinical Immunology, 2021,

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