FROM IMAGING TO DECISION: IMPROVING NONMALIGNANT ASBESTOS HEALTH SCREENING WITH EVIDENCE FROM A LIBBY, MONTANA SCREENING COHORT

Author

• Tracy Jane McNew

Year of Award

2026

Document Type

Dissertation

Degree Type

Doctor of Philosophy (PhD)

Degree Name

Public Health

Department or School/College

School of Public and Community Health Sciences

Committee Chair

Curtis Noonan

Commitee Members

Ethan Walker, Erin Landguth, Tony Ward, Jane Salois

Keywords

asbestos health screening, clinical decision support, high-resolution computed tomography (HRCT), Libby Amphibole asbestos, nonmalignant asbestos-related disease, pleural abnormalities

Abstract

Background: Libby amphibole asbestos (LA) exposure has produced a large screening population with predominantly nonoccupational exposure. Uncertainty persists regarding the clinical significance of early radiologic abnormalities, and guidance for asbestos health screening outside established programs remains limited. This dissertation examined clinical relevance of radiologic abnormalities, evaluated chest radiography (CXR) relative to high-resolution computed tomography (HRCT), and characterized pleural HRCT findings in Libby’s federally funded screening program.

Objectives: The objective was to improve understanding and screening approaches for nonmalignant asbestosrelated disease (ARD) using data from Libby’s amphibole exposed screening population. Aims were to determine whether radiologic abnormalities were clinically meaningful, whether CXR contributed useful information beyond routine clinical factors, and how LA disease presents on HRCT, including whether pleural burden is clinically important.

Methods: Using cross-sectional analyses of participants’ most recent visits from 2011 through 2024, this dissertation used blinded external imaging interpretations, spirometry, and respiratory quality of life measures. Aim 1 evaluated whether pleural and interstitial radiologic abnormalities were associated with worse clinical outcomes. Aim 2 assessed the value of CXR compared to HRCT and developed a consensus informed clinical decision support tool (CDST) for nonmalignant asbestos health screening. Aim 3 evaluated whether increased pleural burden on HRCT was associated with adverse clinical outcomes and characterized pleural HRCT features that define early LA disease.

Results: Across the aims, radiologic abnormalities were shown to be clinically meaningful. Early pleural abnormalities demonstrated modest but important associations with spirometry impairment and worse respiratory quality of life. CXR added little predictive value beyond routine clinical factors, supporting a riskbased screening approach. Expert feedback supported shared decision making in screening. Early HRCT abnormalities were predominantly pleural, and increased pleural burden was associated with abnormal spirometry. The strongest associations were observed for visceral pleural involvement and rounded atelectasis, although both were uncommon.

Conclusions: This dissertation supports the clinical relevance of early nonmalignant abnormalities and strengthens the case for risk-based screening strategies. It also refines the imaging definition of early LA disease and supports screening and clinical decision making for ARD. The findings also improve comparability of LA disease with other asbestos exposed populations.

Recommended Citation

McNew, Tracy Jane, "FROM IMAGING TO DECISION: IMPROVING NONMALIGNANT ASBESTOS HEALTH SCREENING WITH EVIDENCE FROM A LIBBY, MONTANA SCREENING COHORT" (2026). Graduate Student Theses, Dissertations, & Professional Papers. 12681.
https://scholarworks.umt.edu/etd/12681