JMIR Publications

ABSTRACT

Background:

Miners are essential rural workers who may work in close proximity with inadequate ventilation conditions, and who are unable to telecommute or work flexible hours, rendering them vulnerable to SARS-CoV-2 transmission. Limited data indicate that particulate air pollution exposure is associated with and increased risk of SARS-CoV-2 infection and mortality. Chronic exposure to particulate matter causes overexpression of the alveolar angiotensin-converting enzyme 2 (ACE2) receptor, which facilitates the entry of SARS-CoV-2 into lung epithelial cells.

Objective:

We tested the hypothesis that coal miners with higher levels of self-reported particulate exposure (separately from exposure to occupational dust, smoke from residential wood burning and shared transportation) have a greater risk of SARS-CoV-2 infection than miners with lower exposure.

Methods:

We conducted a longitudinal analysis of data obtained from a study conducted from February 2021 to March 2022. For this study 169 surface coal miners in New Mexico and 61 in Wyoming were enrolled. Seropositivity was determined by measuring IgG antibodies to the nucleocapsid protein of SARS-CoV-2, performed by qualitative chemiluminescent immunoassay on plasma samples at baseline, 3, 6, and 12 months after study enrollment. The predictor variables were the self-reported levels of exposure to occupational dust, smoke from wood burning and participation in shared transportation, separately. The primary study outcome was the cumulative seroprevalence at 12 months. Logistic regression analyses were used.

Results:

The study included 44% Hispanic and 13% American Indian, mostly male (88%), miners. Mining dust exposure was associated with a lower cumulative seropositivity of SARS-CoV-2 infection (adjusted OR 0.84, p=0.05). Similar results were noted for baseline and incident seropositivity. However, self-reported exposure to smoke from residential wood burning “very often” was associated with greater baseline infection in the adjusted model (adjusted OR 3.35, 95% Cl: 1.33-8.47, p=.04), whereas a higher frequency of participation in shared transportation was not associated with increased SARS-CoV-2 infection.

Conclusions:

We demonstrate that occupational dust exposure is associated with lower, not higher, odds of cumulative seropositivity in miners. This unexpected finding may be explained by the “healthy worker effect” as well as possibly greater workplace use of masks in dustier jobs for respiratory protection. The study's strengths include a robust enrollment of rural and racial/ethnic minority workers. Our results highlight the need for additional research on how environmental exposures interact with infectious disease dynamics, which may aid in the development of targeted interventions for essential rural workforces. Clinical Trial: NA