A Systematic Analysis of Renal Effects from Chloroform Inhalation Exposure
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Background and Purpose The U.S. Environmental Protection Agency’s Integrated Risk Information System (IRIS) program is currently assessing the human health effects of inhaled chloroform. A systematic evidence map was developed for chloroform exposure via inhalation using Populations, Exposures, Comparators, and Outcomes (PECO) criteria to identify studies relevant to the evaluation of chloroform inhalation exposure.
Methods A comprehensive literature search and screening (title/abstract and full text) were conducted according to systematic review methods. Studies meeting the PECO criteria during screening in DistillerSR software were evaluated, and data from relevant studies were extracted using Health Assessment Workplace Collaborative (HAWC); visualizations of the data were developed using both HAWC and Tableau. Studies containing potentially relevant supplemental material were tracked and categorized as mechanistic and other supportive information. Study confidence ratings (high, medium, low, uninformative) were developed based on evaluation of several domains such as exposure measurement, chemical administration and characterization, confounding factors, observational bias, and sensitivity. Of all the health outcomes assessed, this presentation provides an illustrative example of the analysis of renal effects following inhalation exposure to chloroform from all evidence streams (human, animal, and in vitro).
Results Several animal studies of all durations, primarily in male and female rats and mice, were identified as having renal effects. These included endpoints, such as organ weight, histopathology, and clinical chemistry. A single epidemiological study evaluated blood urea nitrogen (BUN) to assess renal function in exposed workers. Mechanistic endpoints identified include metabolism, oxidative stress, and others.
Conclusions Overall, this systematic evidence map provides an overview of the available renal evidence and helps to inform the usability of these data in the hazard identification and dose-response analysis to be conducted in the forthcoming IRIS assessment of inhaled chloroform exposure.
Disclaimer: The views expressed in this abstract are those of the author(s) and do not necessarily represent the views or the policies of the U.S. Environmental Protection Agency.