The impact of different approaches to exposure assessment on understanding non-malignant respiratory disease risk in taconite miners

Nnaemeka U. Odo, Jeffrey H. Mandel, Bruce H Alexander, David M Perlman, Richard F Maclehose, Gurumurthy Ramachandran, Andrew Ryan, Yuan Shao

Research output: Contribution to journalArticle

Abstract

Introduction: We examined the association between cumulative silica exposures in taconite mining and non-malignant respiratory disease (NMRD) using a comprehensive assessment of current and historical exposure measurements in a cross-sectional study of Minnesota taconite mining workers. We also explored the impact of exposure measurement methods by comparing estimated exposure risk from two different exposure measurement modeling approaches. Methods: Miners were screened with an occupational and medical history questionnaire, spirometry testing and chest x-rays per ILO guidelines. Current and historical occupational exposure assessments were obtained, the former measuring about 679 personal samples over the period of the study for respirable dusts, including silica, in 28 major job functions. Cumulative silica exposure ((mg/m3) × years) was estimated as a cumulative product of time worked and year-specific silica job exposure concentrations. Chest x-ray abnormalities were based on B-reader agreement with a third B-reader for arbitration. Forced vital capacity (FVC) less than lower limits of normal for age, height, race and gender was used to determine spirometric restrictive ventilatory defect (RVD). Prevalence ratios (PR) of exposure-outcome associations, with 95% confidence intervals (CI), were estimated using multivariate Poisson regression. Results: Cumulative silica exposure was associated with RVD prevalence (PR = 1.41, 95% CI = 1.09–1.81) and prevalence of parenchymal abnormalities on chest x-ray (PR = 1.30, 95% CI = 1.00–1.69) using exposure estimates based primarily on current study measurements, and assuming unchanged historical exposure trend. Conversely, when exposures were defined incorporating available actual historical values, no associations were observed between silica exposure and either RVD (PR = 0.76, 95% CI = 0.41–1.40) or parenchymal (PR = 0.87, 95% CI = 0.45–1.70) outcomes. Conclusions: This study demonstrated that the estimated association between silica dust exposure and lung disease is highly sensitive to the approach used to estimate cumulative exposure. Cumulative values based on conservative estimates of past exposure, modeled from recently measured respirable silica, showed an association with restriction RVD on spirometry. Silica exposure was also significantly associated with increased parenchymal findings on chest x-ray using this approach. Conversely, these findings were absent when actual available historical data was used to estimate cumulative silica exposure. These differences highlight the challenges with estimating occupational dust exposure, the potential impact on calculated exposure risk and the need for long term quality exposure data gathering in industries prone to risk from inhaled respirable dusts.

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Silicon Dioxide
Dust
Confidence Intervals
Thorax
X-Rays
Spirometry
Occupational Exposure
taconite
Miners
Vital Capacity
Negotiating
Lung Diseases
Industry
Cross-Sectional Studies
Guidelines

Keywords

  • Exposure methodology
  • Non-malignant respiratory disease
  • Occupational epidemiology
  • Parenchymal abnormalities
  • Prevalence ratio
  • Restrictive ventilatory disease
  • Silica

PubMed: MeSH publication types

  • Journal Article

Cite this

@article{410322004d1f41579e45914f85040bb6,
title = "The impact of different approaches to exposure assessment on understanding non-malignant respiratory disease risk in taconite miners",
abstract = "Introduction: We examined the association between cumulative silica exposures in taconite mining and non-malignant respiratory disease (NMRD) using a comprehensive assessment of current and historical exposure measurements in a cross-sectional study of Minnesota taconite mining workers. We also explored the impact of exposure measurement methods by comparing estimated exposure risk from two different exposure measurement modeling approaches. Methods: Miners were screened with an occupational and medical history questionnaire, spirometry testing and chest x-rays per ILO guidelines. Current and historical occupational exposure assessments were obtained, the former measuring about 679 personal samples over the period of the study for respirable dusts, including silica, in 28 major job functions. Cumulative silica exposure ((mg/m3) × years) was estimated as a cumulative product of time worked and year-specific silica job exposure concentrations. Chest x-ray abnormalities were based on B-reader agreement with a third B-reader for arbitration. Forced vital capacity (FVC) less than lower limits of normal for age, height, race and gender was used to determine spirometric restrictive ventilatory defect (RVD). Prevalence ratios (PR) of exposure-outcome associations, with 95{\%} confidence intervals (CI), were estimated using multivariate Poisson regression. Results: Cumulative silica exposure was associated with RVD prevalence (PR = 1.41, 95{\%} CI = 1.09–1.81) and prevalence of parenchymal abnormalities on chest x-ray (PR = 1.30, 95{\%} CI = 1.00–1.69) using exposure estimates based primarily on current study measurements, and assuming unchanged historical exposure trend. Conversely, when exposures were defined incorporating available actual historical values, no associations were observed between silica exposure and either RVD (PR = 0.76, 95{\%} CI = 0.41–1.40) or parenchymal (PR = 0.87, 95{\%} CI = 0.45–1.70) outcomes. Conclusions: This study demonstrated that the estimated association between silica dust exposure and lung disease is highly sensitive to the approach used to estimate cumulative exposure. Cumulative values based on conservative estimates of past exposure, modeled from recently measured respirable silica, showed an association with restriction RVD on spirometry. Silica exposure was also significantly associated with increased parenchymal findings on chest x-ray using this approach. Conversely, these findings were absent when actual available historical data was used to estimate cumulative silica exposure. These differences highlight the challenges with estimating occupational dust exposure, the potential impact on calculated exposure risk and the need for long term quality exposure data gathering in industries prone to risk from inhaled respirable dusts.",
keywords = "Exposure methodology, Non-malignant respiratory disease, Occupational epidemiology, Parenchymal abnormalities, Prevalence ratio, Restrictive ventilatory disease, Silica",
author = "Odo, {Nnaemeka U.} and Mandel, {Jeffrey H.} and Alexander, {Bruce H} and Perlman, {David M} and Maclehose, {Richard F} and Gurumurthy Ramachandran and Andrew Ryan and Yuan Shao",
year = "2019",
month = "1",
day = "1",
doi = "10.1007/s00420-019-01465-w",
language = "English (US)",
journal = "International Archives of Occupational and Environmental Health",
issn = "0340-0131",
publisher = "Springer Verlag",

}

TY - JOUR

T1 - The impact of different approaches to exposure assessment on understanding non-malignant respiratory disease risk in taconite miners

AU - Odo, Nnaemeka U.

AU - Mandel, Jeffrey H.

AU - Alexander, Bruce H

AU - Perlman, David M

AU - Maclehose, Richard F

AU - Ramachandran, Gurumurthy

AU - Ryan, Andrew

AU - Shao, Yuan

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Introduction: We examined the association between cumulative silica exposures in taconite mining and non-malignant respiratory disease (NMRD) using a comprehensive assessment of current and historical exposure measurements in a cross-sectional study of Minnesota taconite mining workers. We also explored the impact of exposure measurement methods by comparing estimated exposure risk from two different exposure measurement modeling approaches. Methods: Miners were screened with an occupational and medical history questionnaire, spirometry testing and chest x-rays per ILO guidelines. Current and historical occupational exposure assessments were obtained, the former measuring about 679 personal samples over the period of the study for respirable dusts, including silica, in 28 major job functions. Cumulative silica exposure ((mg/m3) × years) was estimated as a cumulative product of time worked and year-specific silica job exposure concentrations. Chest x-ray abnormalities were based on B-reader agreement with a third B-reader for arbitration. Forced vital capacity (FVC) less than lower limits of normal for age, height, race and gender was used to determine spirometric restrictive ventilatory defect (RVD). Prevalence ratios (PR) of exposure-outcome associations, with 95% confidence intervals (CI), were estimated using multivariate Poisson regression. Results: Cumulative silica exposure was associated with RVD prevalence (PR = 1.41, 95% CI = 1.09–1.81) and prevalence of parenchymal abnormalities on chest x-ray (PR = 1.30, 95% CI = 1.00–1.69) using exposure estimates based primarily on current study measurements, and assuming unchanged historical exposure trend. Conversely, when exposures were defined incorporating available actual historical values, no associations were observed between silica exposure and either RVD (PR = 0.76, 95% CI = 0.41–1.40) or parenchymal (PR = 0.87, 95% CI = 0.45–1.70) outcomes. Conclusions: This study demonstrated that the estimated association between silica dust exposure and lung disease is highly sensitive to the approach used to estimate cumulative exposure. Cumulative values based on conservative estimates of past exposure, modeled from recently measured respirable silica, showed an association with restriction RVD on spirometry. Silica exposure was also significantly associated with increased parenchymal findings on chest x-ray using this approach. Conversely, these findings were absent when actual available historical data was used to estimate cumulative silica exposure. These differences highlight the challenges with estimating occupational dust exposure, the potential impact on calculated exposure risk and the need for long term quality exposure data gathering in industries prone to risk from inhaled respirable dusts.

AB - Introduction: We examined the association between cumulative silica exposures in taconite mining and non-malignant respiratory disease (NMRD) using a comprehensive assessment of current and historical exposure measurements in a cross-sectional study of Minnesota taconite mining workers. We also explored the impact of exposure measurement methods by comparing estimated exposure risk from two different exposure measurement modeling approaches. Methods: Miners were screened with an occupational and medical history questionnaire, spirometry testing and chest x-rays per ILO guidelines. Current and historical occupational exposure assessments were obtained, the former measuring about 679 personal samples over the period of the study for respirable dusts, including silica, in 28 major job functions. Cumulative silica exposure ((mg/m3) × years) was estimated as a cumulative product of time worked and year-specific silica job exposure concentrations. Chest x-ray abnormalities were based on B-reader agreement with a third B-reader for arbitration. Forced vital capacity (FVC) less than lower limits of normal for age, height, race and gender was used to determine spirometric restrictive ventilatory defect (RVD). Prevalence ratios (PR) of exposure-outcome associations, with 95% confidence intervals (CI), were estimated using multivariate Poisson regression. Results: Cumulative silica exposure was associated with RVD prevalence (PR = 1.41, 95% CI = 1.09–1.81) and prevalence of parenchymal abnormalities on chest x-ray (PR = 1.30, 95% CI = 1.00–1.69) using exposure estimates based primarily on current study measurements, and assuming unchanged historical exposure trend. Conversely, when exposures were defined incorporating available actual historical values, no associations were observed between silica exposure and either RVD (PR = 0.76, 95% CI = 0.41–1.40) or parenchymal (PR = 0.87, 95% CI = 0.45–1.70) outcomes. Conclusions: This study demonstrated that the estimated association between silica dust exposure and lung disease is highly sensitive to the approach used to estimate cumulative exposure. Cumulative values based on conservative estimates of past exposure, modeled from recently measured respirable silica, showed an association with restriction RVD on spirometry. Silica exposure was also significantly associated with increased parenchymal findings on chest x-ray using this approach. Conversely, these findings were absent when actual available historical data was used to estimate cumulative silica exposure. These differences highlight the challenges with estimating occupational dust exposure, the potential impact on calculated exposure risk and the need for long term quality exposure data gathering in industries prone to risk from inhaled respirable dusts.

KW - Exposure methodology

KW - Non-malignant respiratory disease

KW - Occupational epidemiology

KW - Parenchymal abnormalities

KW - Prevalence ratio

KW - Restrictive ventilatory disease

KW - Silica

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U2 - 10.1007/s00420-019-01465-w

DO - 10.1007/s00420-019-01465-w

M3 - Article

C2 - 31372718

AN - SCOPUS:85070109142

JO - International Archives of Occupational and Environmental Health

JF - International Archives of Occupational and Environmental Health

SN - 0340-0131

ER -