Health & Environmental Research Online (HERO)


Libby Amphibole Asbestos (Draft, 2011)


276 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Diffusing capacity and forced vital capacity in 5,003 asbestos-exposed workers: Relationships to interstitial fibrosis (ILO profusion score) and pleural thickening

Authors: Miller, A; Warshaw, R; Nezamis, J (2013) American Journal of Industrial Medicine 56:1383-1393. HERO ID: 2252658

[Less] BACKGROUND: Asbestosis is an interstitial lung disease whose radiographic severity . . . [More] BACKGROUND: Asbestosis is an interstitial lung disease whose radiographic severity has long been graded by the International Labour Office (ILO) profusion score. Its effect on pulmonary function is further impacted by asbestos related pleural thickening.

OBJECTIVES: This report aims to describe the relationships between radiographic grading of interstitial and pleural fibrosis and a key test of pulmonary function, the diffusing capacity, which measures gas exchange and has rarely been assessed in large groups, and to confirm the relationship to an independent test of pulmonary function, the vital capacity, which measures a mechanical property of the lungs.

METHODS: The data were derived from a survey during the period 1997-2004 of 5,003 workers (all white males) exposed to asbestos in various trades. Tests included chest radiographs read by a certified expert ("B") reader, forced vital capacity (FVC), and carbon monoxide diffusing capacity (DLco). Cigarette smoking was adjusted for in the predictive equation for DLCO . Workers were evaluated at a mobile facility at work sites in four southern states.

RESULTS: Both diffusing capacity and vital capacity were negatively correlated with profusion score over the full spectrum of radiographic severity. ILO profusion scores 0/1 (conventionally classified as normal) and 1/0 (conventionally classified as abnormal) were associated with similar diffusing capacity and vital capacity values. The highest profusion scores were associated with a greater proportionate decrease in diffusing capacity than in FVC. Both tests showed an effect of pleural fibrosis.

CONCLUSIONS: Both radiographic severity graded by the profusion score and pleural thickening are correlated with two independent measures of pulmonary function. FVC (which had been reported in smaller work forces) and DLCO (which has not been reported). Both measures show a decrease from normal to intermediate (0/1, 1/0) scores and a further decrease with greater scores, demonstrating the consistency of radiographic and functional assessments. Am. J. Ind. Med. 56:1383-1393, 2013. © 2013 Wiley Periodicals, Inc.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Functional exercise capacity and health-related quality of life in people with asbestos related pleural disease: an observational study

Authors: Dale, MT; Mckeough, Z; Munoz, PA; Corte, P; Bye, PTP; Alison, JA (2013) BMC Pulmonary Medicine 13. HERO ID: 2248438

[Less] BACKGROUND: Functional exercise capacity in people with asbestos related pleural disease . . . [More] BACKGROUND: Functional exercise capacity in people with asbestos related pleural disease (ARPD) is unknown and there are no data on health-related quality of life (HRQoL). The primary aims were to determine whether functional exercise capacity and HRQoL were reduced in people with ARPD. The secondary aim was to determine whether functional exercise capacity was related to peak exercise capacity, HRQoL, physical activity or respiratory function.

METHODS: In participants with ARPD, exercise capacity was measured by the six-minute walk test (6MWT) and incremental cycle test (ICT); HRQoL by the St George's Respiratory Questionnaire and physical activity by an activity monitor worn for one week. Participants also underwent lung function testing.

RESULTS: 25 males completed the study with a mean (SD) age of 71 (6) years, FVC 82 (19)% predicted, FEV1/FVC 66 (11)%, TLC 80 (19)% predicted and DLCO 59 (13)% predicted. Participants had reduced exercise capacity demonstrated by six-minute walk distance (6MWD) of 76 (11)% predicted and peak work rate of 71 (21)% predicted. HRQoL was also reduced. The 6MWD correlated with peak work rate (r=0.58, p=0.002), St George's Respiratory Questionnaire Total score (r=-0.57, p=0.003), metabolic equivalents from the activity monitor (r=0.45, p<0.05), and FVC % predicted (r=0.52, p<0.01).

CONCLUSIONS: People with ARPD have reduced exercise capacity and HRQoL. The 6MWT may be a useful surrogate measure of peak exercise capacity and physical activity levels in the absence of cardiopulmonary exercise testing and activity monitors.

TRIAL REGISTRATION: ANZCTR12608000147381.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Association of genes of protease-antiprotease balance pathway to lung function and emphysema subtypes

Authors: Kukkonen, MK; Tiili, E; Vehmas, T; Oksa, P; Piirila, P; Hirvonen, Ari (2013) BMC Pulmonary Medicine 13. HERO ID: 2248435

[Less] Background: The imbalance between proteases and antiproteases has been proposed to participate to the . . . [More] Background: The imbalance between proteases and antiproteases has been proposed to participate to the pathogenesis of chronic obstructive pulmonary disease (COPD) and emphysema. Gene level variation in different metalloproteinases, metalloproteinase inhibitors, and cytokines affecting them may contribute to this imbalance and destruction of the lung parenchyma. We investigated whether polymorphisms in selected protease-antiprotease balance pathway genes predispose to different emphysema subtypes (centrilobular, paraseptal, panlobular, and bullae) and airflow limitation among Finnish construction workers.

Methods: Eleven single nucleotide polymorphisms (SNPs) from seven genes (GC: rs7041 and rs4588; MMP1: rs1799750; MMP9: rs3918242; MMP12: rs652438; TIMP2: rs2277698; TNF: rs1799724 and rs1800629; TGFB1: rs1800469, rs1800470, and rs2241718) were analyzed from 951 clinically and radiologically characterized construction workers. The genotype and haplotype data was compared to different emphysematous signs confirmed with high resolution computed tomography (HRCT), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and maximal expiratory flow at 50% of FVC (MEF50) by using linear and logistic regression analyses, adjusted for potential confounders.

Results: The TIMP2 rs2277698 SNP was associated with overall (p = 0.022) and paraseptal (p = 0.010) emphysema, as well as with FEV1/FVC ratio (p = 0.035) and MEF50 (p = 0.008). The TGFB1 rs2241718 and MMP9 rs3918242 SNPs were associated with centrilobular emphysema (p = 0.022 and p = 0.008), and the TNF rs1800629 SNP with paraseptal emphysema (p = 0.017). In stratified analysis, individuals with at least one TIMP2 rs2277698 or TNF rs1800629 variant allele were found to be at around two-fold risk for pathological paraseptal changes (OR 1.94, 95% CI 1.14-3.30; OR 2.10, 95% CI 1.24-3.56). On the contrary, the risk for pathological centrilobular changes was halved for individuals with at least one MMP9 rs3918242 (OR 0.51, 95% CI 0.30-0.86) or TGFB1 rs2241718 (OR 0.53, 95% CI 0.30-0.90) variant allele, or TGFB1 rs1800469-rs1800470 AT-haplotype (OR 0.55, 95% CI 0.33-0.93). MEF50, in turn, was significantly reduced among individuals with at least one TIMP2 rs2277698 variant allele (p = 0.011).

Conclusion: Our findings strengthen the hypothesis of the importance of protease-antiprotease balance in pathogenesis of emphysema and shed light on the aetiology of different emphysema subtypes by associating MMP9 and TGFB1 to centrilobular emphysema, and TIMP2 and TNF to paraseptal emphysema and/or airflow obstruction.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Longitudinal decline in lung function in former asbestos exposed workers

Authors: Algranti, E; Mendonça, EM; Hnizdo, E; De Capitani, EM; Freitas, JB; Raile, V; Bussacos, MA (2013) Occupational and Environmental Medicine 70:15-21. HERO ID: 2078956

[Less] BACKGROUND: This study was designed to assess the effect of asbestos exposure on longitudinal . . . [More] BACKGROUND: This study was designed to assess the effect of asbestos exposure on longitudinal lung function decline.

METHODS: A group of 502 former asbestos-cement workers with at least two spirometry tests 4 years apart. Repeated evaluations included respiratory symptoms questionnaire, spirometry and chest imaging. Asbestos exposure was ascertained as years of exposure, an index of cumulative exposure and latency time. The mixed effects model was used to evaluate the effect of exposure on the level and rate of change in forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC).

RESULTS: Mean age at entry was 51 (SD 9.9) years, mean latency time 25.6 (SD 10.0) years, mean follow-up time 9.1 (SD 2.8) years and mean number of spirometry tests 3.5. The FEV(1) level was significantly related to pack-years of smoking at entry and during the follow-up, the index of cumulative asbestos exposure at entry, and the presence of asbestosis at follow-up. The FVC level was significantly related to pack-years of smoking during the follow-up, cumulative asbestos exposure at entry, asbestosis and pleural thickening at follow-up, and body mass index at entry. Asbestos exposure was not associated with increasing rates of FEV(1) and FVC decline. However, FEV(1) regression slopes with age, estimated by terciles of cumulative exposure, showed significant differences. Combined effects of smoking and exposure conferred further acceleration in lung function decline.

CONCLUSIONS: Occupational exposure in asbestos-cement industry was a risk factor for increased lung function decline. The effect seems to be mostly concentrated during the working period. Smoking and exposure had synergic effects.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Associations between radiographic findings and spirometry in a community exposed to Libby amphibole

Authors: Larson, TC; Lewin, M; Gottschall, EB; Antao, VC; Kapil, V; Rose, CS (2012) Occupational and Environmental Medicine 69:361-366. HERO ID: 1257852

[Less] BACKGROUND: Among asbestos-exposed individuals, abnormal spirometry is usually associated . . . [More] BACKGROUND: Among asbestos-exposed individuals, abnormal spirometry is usually associated with parenchymal abnormalities or diffuse pleural thickening. Localised pleural thickening (LPT), the most common abnormality associated with asbestos exposure, is typically thought to be a marker of exposure with little clinical consequence. Our objective was to determine if abnormal spirometry is associated with LPT independent of other abnormalities, using data from community-based screening conducted in Libby, Montana.

METHODS: Subjects were a subset of screening participants comprising persons with interpretable spirometry and chest radiograph results (n=6475). Chest radiographs were independently evaluated by two or three B readers, and participants were classified by mutually exclusive categories of spirometry outcome: normal, restriction, obstruction or mixed defect.

RESULTS: Restrictive spirometry was strongly associated with parenchymal abnormalities (OR 2.9; 95% CI 1.4 to 6.0) and diffuse pleural thickening (OR 4.1; 95% CI 2.1 to 7.8). Controlling for the presence of these abnormalities as well as age, smoking status and other covariates, restrictive spirometry was also associated with LPT (OR 1.4; 95% CI 1.1 to 1.8). The risk of restrictive spirometric findings correlated with the severity of LPT.

CONCLUSIONS: In this large community-based screening cohort, restrictive spirometry is significantly associated with LPT, indicating that this abnormality may result in lung function impairment. Physicians treating patients exposed to Libby amphibole should be aware that LPT may have functional consequences.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

CT scan screening for lung cancer: risk factors for nodules and malignancy in a high-risk urban cohort

Authors: Greenberg, AK; Lu, F; Goldberg, JD; Eylers, E; Tsay, JC; Yie, TA; Naidich, D; Mcguinness, G; Pass, H; Tchou-Wong, KM; Addrizzo-Harris, D; Chachoua, A; Crawford, B; Rom, WN (2012) PLoS ONE 7:e39403. HERO ID: 2247960

[Less] BACKGROUND: Low-dose computed tomography (CT) for lung cancer screening can reduce . . . [More] BACKGROUND: Low-dose computed tomography (CT) for lung cancer screening can reduce lung cancer mortality. The National Lung Screening Trial reported a 20% reduction in lung cancer mortality in high-risk smokers. However, CT scanning is extremely sensitive and detects non-calcified nodules (NCNs) in 24-50% of subjects, suggesting an unacceptably high false-positive rate. We hypothesized that by reviewing demographic, clinical and nodule characteristics, we could identify risk factors associated with the presence of nodules on screening CT, and with the probability that a NCN was malignant.

METHODS: We performed a longitudinal lung cancer biomarker discovery trial (NYU LCBC) that included low-dose CT-screening of high-risk individuals over 50 years of age, with more than 20 pack-year smoking histories, living in an urban setting, and with a potential for asbestos exposure. We used case-control studies to identify risk factors associated with the presence of nodules (n=625) versus no nodules (n=557), and lung cancer patients (n=30) versus benign nodules (n=128).

RESULTS: The NYU LCBC followed 1182 study subjects prospectively over a 10-year period. We found 52% to have NCNs >4 mm on their baseline screen. Most of the nodules were stable, and 9.7% of solid and 26.2% of sub-solid nodules resolved. We diagnosed 30 lung cancers, 26 stage I. Three patients had synchronous primary lung cancers or multifocal disease. Thus, there were 33 lung cancers: 10 incident, and 23 prevalent. A sub-group of the prevalent group were stable for a prolonged period prior to diagnosis. These were all stage I at diagnosis and 12/13 were adenocarcinomas.

CONCLUSIONS: NCNs are common among CT-screened high-risk subjects and can often be managed conservatively. Risk factors for malignancy included increasing age, size and number of nodules, reduced FEV1 and FVC, and increased pack-years smoking. A sub-group of screen-detected cancers are slow-growing and may contribute to over-diagnosis and lead-time biases.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Continued progression of asbestos-related respiratory disease after more than 15 years of non-exposure

Authors: Bar-Shai, A; Tiran, B; Topilsky, M; Greif, J; Fomin, I; Schwarz, Y (2012) IMAJ 14:560-565. [Abstract] HERO ID: 2078962

[Less] BACKGROUND: Most studies on asbestos-related diseases describe the associations between . . . [More] BACKGROUND: Most studies on asbestos-related diseases describe the associations between exposure and disease and the factors influencing that association. It is recognized that there is a long latency period between exposure and disease, but the health status of affected individuals after long-term non-exposure is uncertain.

OBJECTIVES: To describe the changes in pulmonary function tests (PFTs) and computed tomographic imaging of the thorax over a 15 year period after cessation of exposure to asbestos in a cohort of Israeli power plant workers.

METHODS: Israeli power plant workers whose PFTs and thoracic CT imaging between 1993 and 1998 revealed asbestos-related disease underwent a second clinical, functional and imaging evaluation up to 15 years later. The two sets of results were compared.

RESULTS: Of the original cohort of 59 males, 35 were still alive and 18 of them agreed to take part in the current study. The mean length of their exposure was 30 +/- 10.06 years (range 7-43 years). Comparison of the initial and follow-up examination findings revealed a significant increase in calcification of the pleural plaques (from 37% to 66%, P = 0.008) and a deterioration in PFT results (P= 0.04). Of the 24 men who died, malignant disease was the cause of death in 53%, mostly in sites other than the respiratory system.

CONCLUSIONS: PFTs declined and CT findings worsened in subjects who were formerly exposed to asbestos and had not been exposed to it for over a decade. Continued monitoring of individuals exposed to asbestos, even decades after the cessation of exposure, is recommended.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Biopersistence of Refractory Ceramic Fiber in Human Lung Tissue and a 20-Year Follow-Up of Radiographic Pleural Changes in Workers

Authors: Lockey, JE; Roggli, VL; Hitbert, TJ; Rice, CH; Levin, LS; Borton, EK; Biddinger, PW; Lemasters, GK (2012) Journal of Occupational and Environmental Medicine 54:781-788. HERO ID: 2248440

[Less] OBJECTIVE: The biopersistence of refractory ceramic fiber (RCF) in human lung tissue . . . [More] OBJECTIVE: The biopersistence of refractory ceramic fiber (RCF) in human lung tissue is unknown and may contribute to an association between cumulative fiber exposure and radiographic changes.

METHODS: Lung tissue fiber was analyzed for a case series of 10 RCF workers and a 20-year longitudinal chest radiograph study of 1323 workers was conducted.

RESULTS: Within lung tissue, RCF comprised 14% to 100% of fibers 5 μm or more in length and was identified up to 20 years after RCF employment. Among workers with no reported asbestos exposure, cumulative exposure of more than 63 to 110 and more than 110 fiber-months/cm was associated with radiographic pleural changes of 8.5% (odds ratio, 7.2; 95% confidence interval, 1.4 to 36.8) and 11.6% (odds ratio, 10.3; 95% confidence interval, 2.1 to 49.9), respectively.

CONCLUSIONS: Refractory ceramic fiber can persist in human lung tissue for up to 20 years and may contribute to the significant association between cumulative fiber exposure and radiographic pleural changes.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Adipokine adipsin is associated with the degree of lung fibrosis in asbestos-exposed workers

Authors: Leivo-Korpela, S; Lehtimaki, L; Nieminen, R; Oksa, P; Vierikko, T; Jarvenpaa, R; Uitti, J; Moilanen, E (2012) Respiratory Medicine 106:1435-1440. HERO ID: 1553764

[Less] OBJECTIVES: Asbestos-exposure causes an inflammatory response driven by alveolar macrophages . . . [More] OBJECTIVES: Asbestos-exposure causes an inflammatory response driven by alveolar macrophages that can lead to pulmonary fibrosis. In addition to classical inflammatory cytokines, macrophages produce adipokines which regulate the inflammatory response. We studied if adipokines are related to the degree of parenchymal fibrosis, impaired lung function and inflammation in asbestos-exposed subjects.

METHODS: Eighty-five males with moderate to heavy occupational exposure to asbestos and unexposed controls were studied. We measured plasma levels of adipokines adiponectin, adipsin, leptin and resistin, IL-6, IL-8, erythrocyte sedimentation rate (ERS), spirometry and D(L,CO). Degree of interstitial lung fibrosis (septal thickening, subpleural lines, parenchymal bands or honeycombing) was scored in classes 0-5 according to a validated scoring system. The subjects were divided into three groups: normal parenchymal finding (fibrosis class 0), borderline changes (classes 0.5-1.5) and fibrosis (i.e. asbestosis; classes 2-5).

RESULTS: Adipsin correlated positively with parenchymal fibrosis (rho=0.412, p<0.001) and there was a linear increasing trend of mean plasma adipsin levels among the three groups of asbestos-exposed subjects (from normal parenchymal finding to borderline changes and to fibrosis) (p<0.0001). Accordingly, plasma adipsin levels correlated positively with the extent of pleural plaques (r=0.245, p=0.043), and negatively with D(L,CO) (r=-0.246, p=0.023). Also, a positive correlation was found between adipsin and inflammatory markers ESR (r=0.315, p=0.008) and IL-6 (r=0.256, p=0.018).

CONCLUSIONS: Adipsin was associated with the degree of parenchymal fibrosis, impairment of pulmonary diffusing capacity and with inflammatory activity in asbestos-exposed subjects suggesting that adipsin may have a role in the pathogenesis or as a biomarker in asbestos-induced lung disease.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Localized pleural thickening: smoking and exposure to Libby vermiculite

Authors: Christensen, KY; Kopylev, L (2012) Journal of Exposure Science and Environmental Epidemiology 22:320-323. HERO ID: 1257859

[Less] There is limited research on the combined effects of smoking and asbestos exposure on risk of localized . . . [More] There is limited research on the combined effects of smoking and asbestos exposure on risk of localized pleural thickening (LPT). This analysis uses data from the Marysville cohort of workers occupationally exposed to Libby amphibole asbestos (LAA). Workers were interviewed to obtain work and health history, including ever/never smoking and chest X-rays. Cumulative exposure estimates were developed on the basis of fiber measurements from the plant and work history. Benchmark concentration (BMC) methodology was used to evaluate the exposure-response relationship for exposure to LAA and a 10% increased risk of LPT, considering potential confounders and statistical model forms. There were 12 LPT cases among 118 workers in the selected study population. The mean exposure was 0.42 (SD=0.77) fibers/cc-year, and the prevalence of smoking history was 75.0% among cases and 51.9% among non-cases. When controlling for LAA exposure, smoking history was of borderline statistical significance (P-value=0.099), and its inclusion improved model fit, as measured by Akaike's Information Criterion. A comparison of BMC estimates was made to gauge the potential effect of smoking status. The BMC was 0.36 fibers/cc-year, overall. The BMC for non-smokers was approximately three times as high (1.02 fibers/cc-year) as that for the full cohort, whereas the BMC for smokers was about 1/2 that of the full cohort (0.17 fibers/cc-year).