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. 2023 Jul;66(7):573-586.
doi: 10.1002/ajim.23485. Epub 2023 Apr 23.

An algorithm for quantitatively estimating occupational endotoxin exposure in the biomarkers of exposure and effect in agriculture study: II. Application to the study population

Melissa C Friesen  1 , Laura E Beane Freeman  1 , Sarah J Locke  1 , Pabitra R Josse  1 , Shuai Xie  1 , Susan Marie Viet  2 , Jean-François Sauvé  3 , Gabriella Andreotti  1 , Peter S Thorne  4 , Jonathan N Hofmann  1
Affiliations

An algorithm for quantitatively estimating occupational endotoxin exposure in the biomarkers of exposure and effect in agriculture study: II. Application to the study population

Melissa C Friesen et al. Am J Ind Med. 2023 Jul.

Abstract

Background: We developed an algorithm to quantitatively estimate endotoxin exposure for farmers in the Biomarkers of Exposure and Effect in Agriculture (BEEA) Study.

Methods: The algorithm combined task intensity estimates derived from published data with questionnaire responses on activity duration to estimate task-specific cumulative endotoxin exposures for 13 tasks during four time windows, ranging from "past 12 months" to "yesterday/today." We applied the algorithm to 1681 participants in Iowa and North Carolina. We examined correlations in endotoxin metrics within- and between-task. We also compared these metrics to prior day full-shift inhalable endotoxin concentrations from 32 farmers.

Results: The highest median task-specific cumulative exposures were observed for swine confinement, poultry confinement, and grind feed. Inter-quartile ranges showed substantial between-subject variability for most tasks. Time window-specific metrics of the same task were moderately-highly correlated. Between-task correlation was variable, with moderately-high correlations observed for similar tasks (e.g., between animal-related tasks). Prior day endotoxin concentration increased with the total metric and with task metrics for swine confinement, clean other animal facilities, and clean grain bins.

Significance: This study provides insight into the variability and sources of endotoxin exposure among farmers in the BEEA study and summarizes exposure estimates for future investigations in this population.

Keywords: bioaersosol exposures; endotoxin exposures; farming activities; occupational questionnaires.

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Figures

Figure 1
Figure 1
Proportion of participants who completed the version 2014 questionnaire reporting performing endotoxin-exposed tasks in the ‘past 30 days’ prior to interview (circles) and the median (dark line in box) and inter-quartile range (upper and lower limits of box) of the duration of the task when performed. Tasks sorted from least to most frequently reported.
Figure 2
Figure 2
Median (dark line) and interquartile range (lower and upper limits of boxes) for the task-specific and total endotoxin metrics for the ‘past 30 day’ metrics for all participants based on first interview.
See this image and copyright information in PMC

References

    1. Douwes J, Thorne P, Pearce N, et al. Bioaerosol health effects and exposure assessment: progress and prospects. Ann Occup Hyg 2003;47:187–200. - PubMed
    1. Thorne PS, Mendy A, Metwali, N, et al. Endotoxin Exposure: Predictors and Prevalence of Associated Asthma Outcomes in the United States. Am J Respir Crit Care Med 2015;192:1287–1297. - PMC - PubMed
    1. Thorne PS, Duchaine C, Blais Le Cours P. Airborne Bacteria, Archaea, and Endotoxin. In Yates M, Nakatsu C, Miller R, Pillai S, editors. Manual of Environmental Microbiology, 4th Edition. ASM Press; 2016.
    1. Eduard W, Douwes J, Omenaas E, et al. Do farming exposures cause or prevent asthma? Results from a study of adult Norwegian farmers. Thora 2004;59:381–386 - PMC - PubMed
    1. Basinas I, Elholm G, Wouters IM. Endotoxins, glucans and other microbial cell wall agents. In Viegas C, Viegas S, Gomes A, Täubel M, Sabino R, editors. Exposure to Microbiological Agents in Indoor and Occupational Environments Springer Berlin Heidelberg; 2017.

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