# Heavy metal exposure, genetic predisposition, and auditory dysfunction: A cross-sectional study in a high-risk urban cohort

> **NIH NIH K01** · WAYNE STATE UNIVERSITY · 2020 · $131,174

## Abstract

ABSTRACT
 Exposures to environmental lead and cadmium can generate reactive oxygen species and have
been linked to hearing impairment in high-risk communities. Because sensory receptor cells in the inner
ear cannot regenerate, oxidative stress-induced damage to these cells is permanent, and consequent
hearing loss persists throughout life. Even low levels of toxicants—when they co-occur with other risk
factors, whether environmental or genetic—can cause significant impairment. However, the complex
interactions between exposure to environmental ototoxicants and genetic susceptibility to hearing
impairment are poorly understood. The long-term objective of my work is to understand gene-
environment interactions in hearing impairment in high-risk communities, potentially providing a scientific
basis for future environmental health policies. Firefighters are a high-risk population who are often co-
exposed to multiple environmental risk factors. The proposed study will investigate the independent and
interactive effects of environmental exposures and genetic risks on hearing impairment. Specifically, I
hypothesize that distinct polymorphisms of SOD2 enhances the risk of hearing impairment associated
with lead and cadmium exposure. The Specific Aims are to 1) determine the association between lead
and cadmium exposure and hearing impairment in firefighters and 2) evaluate the interaction among
SNPs of SOD2, lead and cadmium exposure, and hearing impairment. Audiograms will be used to
assess hearing impairment. Bone lead levels will be analyzed by K-X-ray fluorescence imaging and
urinary cadmium levels will be analyzed by ICP-mass spectrometry. Questionnaires and firefighter
service records will be used to determine prior exposures to risk factors that are known to contribute to
hearing impairment and that could confound the associations under study. Salivary DNA will be used to
determine the distribution of 2 SNPs of SOD2 that are known to be associated with acquired hearing
loss. Hearing impairment will be operationalized for analysis as a continuous measure representing the
hearing thresholds. By identifying the combined influence of genetic and environmental risk factors, this
study will facilitate the design of targeted hearing conservation programs that minimize co-exposure to
potentiating environmental toxicants, which in turn could significantly decrease the incidence of hearing
loss in high-risk communities. Further, the successful completion of the proposed research will enable
the principal investigator of this TIEHR-K01 award, Dr. Samson Jamesdaniel, to develop greater
competence 1) in designing and implementing research programs involving high-risk populations in
vulnerable communities, 2) as a collaborator in epidemiologic studies, and 3) in employing
multidisciplinary approaches to address important research questions. These efforts will help to establish
the PI as an independent investigator of environmental health issues affecting urban...

## Key facts

- **NIH application ID:** 9829573
- **Project number:** 5K01ES028750-03
- **Recipient organization:** WAYNE STATE UNIVERSITY
- **Principal Investigator:** SAMSON JAMESDANIEL
- **Activity code:** K01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $131,174
- **Award type:** 5
- **Project period:** 2017-12-01 → 2021-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9829573

## Citation

> US National Institutes of Health, RePORTER application 9829573, Heavy metal exposure, genetic predisposition, and auditory dysfunction: A cross-sectional study in a high-risk urban cohort (5K01ES028750-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9829573. Licensed CC0.

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