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Biomedical subjects

J A Merchant

Publications and source records attributed to J A Merchant.

At least 37 records · Page 2Linked to original sources
PubMed1995

Determinants of longitudinal changes in spirometric function among swine confinement operators and farmers.

To assess whether working in a swine confinement facility causes an excess or accelerated decline in lung function, we conducted a population-based study to evaluate the determinants of longitudinal changes in airflow in a population of swine confinement operators. Spirometric measures of lung function were compared between swine confinement operators (N = 168) and neighborhood farmer control subjects (N = 127). Study subjects were randomly selected from a cohort of swine confinement operators in eastern Iowa. The control farming population was matched by geographic location, age, and sex to the swine confinement operators. On average, the follow-up time was approximately 2 yr, with a range of follow-up between 56 and 1,900 d. Although swine confinement operators and neighborhood farmers had similar demographic characteristics (age, gender, racial background, smoking history, and atopy status), swine confinement operators tended to have less farming experience and were more extensively followed (more measures of lung function and longer periods of observation) than the neighborhood farmer control group. Swine confinement operators were also exposed to higher environmental dust concentrations and other irritants than the farmer control subjects. Interestingly, the cross-sectional data indicated that swine confinement operators tended to have slightly lower measures of airflow and greater workshift declines in forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and mid-expiratory flow (FEF25-75) than the neighborhood farmer control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Peak flow as a measure of airway dysfunction in swine confinement operators.

To evaluate the usefulness of a portable peak flow meter in predicting airway dysfunction in symptomatic swine confinement workers, we conducted a study using an established cohort of swine workers in Iowa. Participants were randomly selected from a group of 207 swine confinement workers and a group of nonconfinement farmers who had been followed longitudinally. Swine confinement workers with work-related symptoms were identified, and two control groups (swine confinement workers and nonconfinement workers) without work-related symptoms were frequency matched by age, sex, and smoking status to the symptomatic swine confinement workers. Peak flow measures were obtained for 7 days using a mini-Wright peak flow meter and comparisons were made between the symptomatic swine confinement farmers (n = 24) and both groups of asymptomatic workers: swine confinement workers (n = 21) and neighborhood farmer controls (n = 25). Peak flow readings were recorded by subjects five times per day for 7 days, initially on awakening, then after chores, before lunch, before dinner, and before bedtime. The actual hour of day for each measurement of peak flow was similar between the three groups. Percent changes from initial AM peak flow did not significantly differ between subject groups. However, symptomatic swine confinement workers consistently exhibited significantly lower initial and subsequent mean peak flow values compared with asymptomatic swine confinement workers and neighborhood control farmers, controlling for age, height, gender, and smoking status. These differences occurred on most of the measures of peak flow throughout the work day. The persistence of these lower values throughout the work day is remarkably consistent during the study period and is suggestive of airway disease in the symptomatic swine confinement workers. Our findings suggest that peak flow meters are a useful indicator of potential airway injury and offer an additional portable, diagnostic tool in the assessment of symptomatic workers.

Adult↗
PubMed1994

High-resolution CT-derived measures of lung density are valid indexes of interstitial lung disease.

To assess the validity of computer-assisted methods in analyzing the lung parenchyma imaged with high-resolution computed tomography (HRCT), we compared computer-derived estimates of lung density to other, more traditional, measures of parenchymal injury in 24 subjects with idiopathic pulmonary fibrosis (IPF) and 60 subjects with extensive occupational exposure to asbestos. Gray scale density histograms were constructed from the HRCT images. The gray scale histogram of both study groups was of a skewed unimodal distribution. However, compared with the asbestos-exposed subjects, the patients with IPF had a gray scale distribution that was significantly shifted to the right (greater density) and flatter. In a multivariate analysis, after controlling for age and cigarette smoking, we found that the mean and median gray scale densities were independently associated with the presence of moderate-to-severe dyspnea, a higher International Labour Office chest X-ray category, a lower forced vital capacity, and a higher concentration of macrophages and eosinophils in the bronchoalveolar lavage fluid. These factors accounted for > 70% of the variance of the mean and median gray scale densities. Interestingly, no differences in gray scale density measures were noted between patients with IPF and patients with asbestosis when these other factors were taken into account. Our results suggest that computer-derived density analysis of the lung parenchyma on the HRCT scan is a valid, clinically meaningful, and objective measure of interstitial lung disease.

Asbestosis↗
PubMed1994

Longitudinal changes in lung function among asbestos-exposed workers.

To prospectively identify the determinants of persistent or accelerated loss of lung function among workers occupationally exposed to asbestos and assess the relative contribution of cigarette smoking, asbestos-induced pleural fibrosis, and specific findings from bronchoalveolar lavage and high resolution CT scans, we examined the determinants of lung function changes in 117 subjects occupationally exposed to asbestos for at least 1 yr in a high exposure setting. A minimum of 20 yr was required between the first exposure to asbestos and entry into the study. Baseline studies included an independent assessment of dyspnea, lung volumes, diffusing capacity of carbon monoxide (DLCO), a chest radiograph, a high resolution CT (HRCT) scan, and bronchoalveolar lavage (BAL). Subjects were observed for an average of 2 yr (range, 0.5 to 4.0 yr), and lung function was measured on at least two separate occasions (mean, 4.1 separate tests). During the period of observation, there was an average 1.5% decrease in the TLC and a 2.5% decrease in the DLCO. In this longitudinal data set, after controlling for age, height, pack-years of cigarette smoking, and follow-up time, persistently lower measures of TLC were independently related to moderate to severe dyspnea (p = 0.005), diffuse pleural thickening (p = 0.007), and higher concentrations of fibronectin in BAL fluid (p = 0.01). Interstitial lung disease either on the chest radiograph or HRCT scan was not independently associated with persistently lower measures of TLC during the period of observation. However, none of the clinical variables we examined were associated with an accelerated decline in TLC.(ABSTRACT TRUNCATED AT 250 WORDS)

Asbestos↗
PubMed1994

Asbestos-induced pleural fibrosis and impaired exercise physiology.

To further assess the clinical significance of asbestos-induced pleural fibrosis, we performed cardiopulmonary exercise testing in 90 subjects who were exposed to asbestos. Of the 82 subjects without an abnormal resperate exercise, 35 had normal pleura, 33 had circumscribed pleural plaques, and 14 had diffuse pleural thickening. Interstitial fibrosis (International Labor Organization [ILO]. > or = 1/10) was present in 14 of 35 subjects with normal pleura, 13 of 33 subjects with circumscribed pleural plaques, and 2 of 14 subjects with diffuse pleural thickening. Although pleural fibrosis did not appear to be related to impaired respiratory function with exercise in our entire cohort, this finding was confounded by a higher proportion of interstitial fibrosis in subjects with normal pleura. In fact, among study subjects without asbestosis, significant decreases in gas exchange (higher VD/VT and increased alveolar-arterial oxygen pressure difference) were observed at maximal exercise among subjects with pleural fibrosis. Interestingly, neither a higher respiratory rate nor a lower VT/FVC ratio was observed among those with pleural fibrosis, suggesting that the mechanical effects of pleural fibrosis on the chest wall do not explain the increased VD/VT. Using multivariate analyses to control for potential confounders, regression models showed that pleural plaques (p = 0.04) and diffuse pleural thickening (p = 0.03) were independently associated with significant increases in dead space ventilation (VD/VT) with maximal exercise. These findings indicate that asbestos-induced pleural fibrosis is independently associated with decrements in gas exchange with maximal exercise and suggest that interstitial lung disease, not detected on the routine chest x-ray film, may be responsible for this abnormal response to exercise.

Asbestos↗
PubMed1993

Inhaled aeroallergen and storage mite reactivity in a Wisconsin farmer nested case-control study.

A nested case-control study was undertaken to assess the role of antibody (Ab) to a panel of antigens associated with hypersensitivity pneumonitis in the development of lung disease among Wisconsin dairy farmers. Immunologic reactivity to a panel of inhaled allergens was assessed in the Ab+ cases and compared to the Ab+ control, Ab- control, and Ab- blue-collar control subjects by skin tests, RAST assays, and a modified American Thoracic Society questionnaire. The most prevalent allergens among the cases as determined by either skin test or RAST assays were the house dust mites (HDM) (21.6%), storage mites (11.2%), grain smuts (11.2%), Cladosporium (7.5%), Aspergillus (6.0%), and cattle (5.2%). No other allergens appeared to be different from in nonfarming populations. Of the storage mite reactors, IgE to Lepidoglyphus destructor (7 of 8) was the most frequently found, followed by Tyrophagus putrescentiae (6 of 8), Glycyphagus domesticus (5 of 8), Chortoglyphus arcuatus (5 of 8), and Acarus siro (2 of 8). L. destructor was also isolated from the farm of one of the cases. There was no difference in the total IgE levels among the groups. Reactions to HDM, storage mites, and grain smuts were significantly more frequent among the cases (p < 0.05). We conclude from this study that there is a significant increase in reactivity to certain inhaled allergens among those dairy farmers reporting barn-associated respiratory symptoms that is unrelated to past exposure to the causative agents of farmer's lung disease.

Agricultural Workers' Diseases↗
PubMed1993

Clinical relevance of cellular mediators of inflammation in workers exposed to asbestos.

To identify the clinical relevance of cellular mediators of inflammation in workers exposed to asbestos, we investigated the relationship between inflammatory products primarily released by alveolar macrophages and the clinical expression of asbestos-induced interstitial fibrosis. Our study population consisted of 93 white men who had been occupationally exposed to asbestos and were on average 60 yr of age. Pulmonary function tests, chest radiographs, high-resolution CT scans, and bronchoalveolar lavage (BAL) were performed on almost all study subjects; 11 (11.8%) had restrictive lung function, 22 (23.7%) had abnormal gas exchange, 30 (32.3%) had interstitial fibrosis on chest x-ray, and 24 (25.8%) had interstitial changes on high-resolution CT scan. The cellular markers of parenchymal inflammation that we examined included fibronectin in BAL fluid and alveolar macrophage release of prostaglandin E2 (PGE2), interleukin-1 beta (IL-1 beta), and tumor necrosis factor (TNF-alpha) under unstimulated and endotoxin (LPS)-stimulated culture conditions. Significantly higher concentrations of fibronectin in BAL fluid were observed among those with restrictive lung function. In addition, higher concentrations of PGE2, released from cultured but otherwise unstimulated alveolar macrophages, were associated with restrictive lung function. However, the inverse relationship with PGE2 was observed among subjects with abnormal gas exchange. Interestingly, no consistent changes in these inflammatory mediators were observed in those with interstitial changes identified on either the chest radiograph or the high-resolution CT scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Restrictive lung function and asbestos-induced pleural fibrosis. A quantitative approach.

To assess further the clinical significance of asbestos-induced pleural fibrosis, we used a computer algorithm to reconstruct images three dimensionally from the high-resolution computerized tomography (HRCT) scan of the chest in 60 asbestos-exposed subjects. Pulmonary function tests, chest radiographs, and HRCT scans were performed on all study subjects. The volume of asbestos-induced pleural fibrosis was computed from the three-dimensional reconstruction of the HRCT scan. Among those with pleural fibrosis identified on the HRCT scan (n = 29), the volume of the pleural lesion varied from 0.01% (0.5 ml) and 7.11% (260.4 ml) of the total chest cavity. To investigate the relationship between asbestos-induced pleural fibrosis and restrictive lung function, we compared the computer-derived estimate of pleural fibrosis to the total lung capacity and found that these measures were inversely related (r = -0.40; P = 0.002). After controlling for age, height, pack-years of cigarette smoking, and the presence of interstitial fibrosis on the chest radiograph, the volume of pleural fibrosis identified on the three-dimensional reconstructed image from the HRCT scan was inversely associated with the total lung capacity (P = 0.03) and independently accounted for 9.5% of the variance of this measure of lung volume. These findings further extend the scientific data supporting an independent association between pleural fibrosis and restrictive lung function.

Aged↗
PubMed1993

The relationship between HLA-A, B, DQ, and DR antigens and asbestos-induced lung disease.

To evaluate the relationship between human leukocyte antigen (HLA) and both asbestos-induced pulmonary fibrosis and pleural fibrosis, we obtained HLA-A, B, C, DQ, and DR phenotypes in 42 long-term asbestos-exposed workers. Among these exposed workers, 15 had asbestosis (ILO > or = 1/0) on the chest radiograph and 18 had asbestos-induced pleural fibrosis. We found that there was an increased percentage of HLA-A29, HLA-B44, and HLA-Bw4 in the subjects with asbestosis. In addition, we observed a marginally positive relationship between HLA-A29 and the severity of pulmonary fibrosis. Similarly, there was a higher prevalence of HLA-DRw53 and DQ2 in the subjects with asbestos-induced pleural fibrosis. The presence of HLA-DQ2 was significantly related to the extent and type of asbestos-induced pleural fibrosis while HLA-DRw53 was not consistently related to the type or extent of pleural disease. Importantly, we observed that HLA-A29, HLA-B44, HLA-Bw4, HLA-DRw53, and HLA-DQ2 do not have a significantly shorter duration or latency of asbestos exposure. Moreover, none of the HLA haplotypes (A29, B44, Bw4, DRw53, and DQ2) that we found to be associated with radiographic manifestations of asbestos-induced lung disease were associated with the physiologic abnormalities that have been traditionally associated with asbestos-induced lung disease. The only exception was an isolated decrease in the residual volume associated with the presence of HLA-A29. These results suggest that the HLA-A29 phenotype may be associated with the development of asbestosis and the HLA-DQ2 phenotype may be associated with the development of asbestos-induced pleural fibrosis. However, these associations are not particularly strong, physiologic correlation is lacking, and previous studies do not support our findings.

Asbestosis↗
PubMed1992

Airway injury in swine confinement workers.

OBJECTIVE: To determine whether work-related respiratory symptoms are indicative of underlying lung disease among swine confinement workers and, if so, to identify whether respiratory changes were more indicative of airway or of interstitial lung injury. DESIGN: Nested case-control study within a population-based longitudinal study. SETTING: University hospital. PARTICIPANTS: Study participants were randomly selected from a group of 207 swine confinement workers followed longitudinally. Of these, 43 workers with respiratory symptoms were identified, and 31 were randomly selected for inclusion in this study. Three control groups (swine confinement workers, neighbor farmers, and blue collar workers) without work-related respiratory symptoms were frequency-matched by age, sex, and smoking status to the symptomatic swine confinement workers. MEASUREMENTS: Spirometry and lung volumes, diffusing capacity of carbon monoxide, chest radiograph, methacholine airway challenge, and bronchoalveolar lavage were done. An endobronchial biopsy was done in the last 27 participants evaluated. RESULTS: Although spirometric measures of airflow were similar between the symptomatic swine confinement workers and the three control groups, swine confinement cases were found to have significant elevations in residual volume (126.5 +/- 28.2 L) when compared to swine confinement controls (115.4 +/- 38.4 L; P less than or equal to 0.05), neighborhood farmer controls (101.1 +/- 29.4 L; P less than or equal to 0.005), and blue collar controls (106.4 +/- 30.4 L; P less than or equal to 0.05). Swine confinement cases also had an enhanced airway response to inhaled methacholine and had thickening of the epithelial basement membrane of the lobar bronchi. No parenchymal injury was observed in the swine confinement cases. CONCLUSIONS: Our findings suggest that swine confinement workers who have work-related respiratory symptoms are at risk for airway, but not parenchymal, lung injury, and that spirometry may not accurately reflect the extent of airway injury.

Adult↗
PubMed1992

Influence of cigarette smoking on bronchoalveolar lavage cellularity in asbestos-induced lung disease.

To investigate the influence of cigarette smoking on bronchoalveolar lavage (BAL) cellularity in asbestos-induced lung disease, we compared BAL cells in asbestos-exposed, nondiseased subjects (n = 20) with those with either asbestosis (n = 25) or asbestos-induced pleural fibrosis (n = 28). Patients with asbestosis (ILO greater than or equal to 1/0) had higher concentrations of BAL macrophages (p = 0.04), neutrophils (p = 0.003), and eosinophils (p = 0.01), while patients with asbestos-induced pleural fibrosis (circumscribed plaques and diffuse pleural thickening) had higher concentrations of BAL lymphocytes (p = 0.02). Within our study population, however, cigarette smoking (smoking status or pack-years of smoking) was strongly associated with BAL macrophages, neutrophils, and eosinophils but was not associated with the concentration of BAL lymphocytes. Using multivariate analysis, we found that although asbestosis remained associated with higher concentrations of BAL macrophages, neutrophils, and eosinophils, cigarette smoking had a far greater contribution to the concentrations of BAL macrophages and eosinophils than did asbestosis. Although cigarette smoking accounted for 17 to 18% of the variance of BAL macrophages and eosinophils, asbestosis was associated with approximately 6% of the variance associated with these cells. In contrast, the concentration of BAL neutrophils remained associated with asbestosis and was not influenced by smoking behavior. We conclude that cigarette smoking strongly influences BAL cellularity (macrophages and eosinophils) in our patients with asbestosis but does not appear to affect the type or concentration of BAL cells in patients with asbestos-induced pleural fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Asbestosis↗
PubMed1992

Pleural determinants of restrictive lung function and respiratory symptoms in an asbestos-exposed population.

To further define the relationship between asbestos-induced pleural fibrosis and restrictive lung function, we investigated the pleural determinants of respiratory symptoms and restrictive physiology in 1,211 sheet metal workers. We evaluated the relationship between specific components of pleural fibrosis (costophrenic angle involvement, diaphragmatic plaques, width and length of pleural fibrosis, pleural calcification, and the type of fibrosis-circumscribed plaque or diffuse pleural thickening) and both forced vital capacity and respiratory symptoms. We found that costophrenic angle involvement, the width and length of pleural fibrosis, and the presence of either circumscribed plaque or diffuse pleural thickening were each significantly associated with a lower FVC. No consistent relationship was observed between FVC and either diaphragmatic plaques or pleural calcification. However, since the pleural abnormalities were highly collinear, none of these abnormalities alone or in combination predicted the reduction in FVC significantly better than a model that included circumscribed plaques and diffuse pleural thickening. We also investigated the relationship of each component of pleural fibrosis with cough, dyspnea, and chest pain. After controlling for appropriate confounders, a trend toward significance was observed between increased width and length of fibrosis and dyspnea with exertion. Otherwise, these pleural abnormalities were not consistently related to any of the three respiratory symptoms. Our results indicate that although pleural plaques and diffuse pleural thickening and their components are independently associated with a lower FVC, these components of pleural fibrosis do not substantially improve the previously defined relationship between FVC and both circumscribed plaques and diffuse pleural thickening. In addition, a trend toward significance was observed between the width and length of the pleural abnormality and dyspnea while hurrying.

Asbestosis↗
PubMed1991

The clinical utility and reliability of asbestos bodies in bronchoalveolar fluid.

Although asbestos bodies are easily identified in bronchoalveolar lavage (BAL) fluid and are thought to be strongly associated with the asbestos body burden in the lung parenchyma, the clinical utility and reliability of this biologic measure of exposure has not been sufficiently studied. To assess the clinical relevance of BAL asbestos bodies we compared this bioassay of exposure to other measures of exposure and also indices of lung disease in asbestos-exposed workers (n = 71). The median concentration of asbestos bodies was 0.8 bodies per ml of BAL fluid (range 0 to 34.3). Seven workers or 9.9% had zero asbestos bodies identified in the BAL fluid. The concentration of BAL asbestos bodies was not associated with the duration of exposure (r = -0.02), the time from first exposure to asbestos (r = 0.12), or the time since last exposure to asbestos (r = 0.05). Moreover, radiographic and physiologic measures of asbestos-induced lung disease were not found to be associated with the concentration of BAL asbestos bodies. In fact, of the seven study subjects with zero BAL asbestos bodies, the mean duration of exposure was 32 yr, and six of these subjects had radiographic evidence of asbestos-induced lung disease. To assess the reliability of measuring BAL asbestos bodies, we performed a second bronchoscopy on 54 subjects and directly compared the concentration of BAL asbestos bodies from both the first and second BAL samples. Within these 54 subjects, the concentration of BAL asbestos bodies was found to be a very reliable measure (r = 0.76; p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Asbestos↗
PubMed1990

1983 occupational injury hospital admissions in Iowa: a comparison of the agricultural and non-agricultural sectors.

An occupational injury surveillance project was conducted in 15 of Iowa's 99 counties. Trained abstractors reviewed the medical records of persons admitted for trauma to hospitals during 1983. Based on these chart reviews, subsequent mail-out questionnaires and phone contacts were made, and rate estimates for occupational injury hospitalization for farmers and non-farmers were generated. The 1980 U.S. census data for occupation and market area data for the sample hospitals were used for the rate calculations. Approximately 14.7% of hospitalizations for trauma in the sample area were for work-related injuries. Farmers were hospitalized for occupational injuries at a rate of 1,521/100,000 compared to non-farmers at a rate of 497/100,000. There were no significant differences in the mean number of days per hospitalization for farmers versus non-farmers, (7.4 days for farmers and 6.7 days for non-farmers). Based on the questionnaire data, farmers were much less likely to receive any form of remuneration for injury, (odds ratio = 0.26, p less than 5 x 10(-6]. Farmers also reported less time off from work, with a mean of 79 days compared to non-farmers with a mean of 289 days.

Accidents, Occupational↗
PubMed1990

Preventing respiratory disease in swine confinement workers: intervention through applied epidemiology, education, and consultation.

A combined epidemiological and intervention study was conducted on 207 swine confinement farmers with matched comparison subjects. The objectives of the study were to define, in detail, the nature and disease determinants in this exposed group and to explore methods of disease prevention. This 5 year prospective study included three annual medical assessments of workers and complementary work environment assessments. Between the first and second assessment periods, an in-depth educational intervention was conducted. An industrial hygiene consultation intervention was conducted between the second and third measurement periods. Outcome measurements included changes in knowledge, attitudes, and behavior following educational intervention. Additionally, the outcomes measured included changes in medical and environmental assessment over the 3 year assessment periods. Results of the baseline respiratory symptoms assessment are reported here. Nearly 20% of swine confinement workers reported chronic cough, and 25% reported phlegm (American Thoracic Society questionnaire). Both symptoms were significantly more prevalent in the confinement workers compared to a blue collar comparison group, but only phlegm production was more prevalent compared to nonconfinement farmers. Work-related symptoms were reported much more frequently than chronic symptoms (e.g., 87% of confinement workers reported work-related cough). Bronchitis as well as airways reactivity were all significantly more prevalent in confinement workers compared to nonconfinement workers. Smoking seemed to have an additive effect with confinement exposure. Bronchitis and chest tightness symptoms were reported to be more severe upon return to work after an absence of 7 days or more. Finally, 34% of workers reported episodes of organic dust toxic syndrome.

Adult↗
PubMed1990

Cohort studies of immunologic lung disease among Wisconsin dairy farmers.

Traditionally, hypersensitivity pneumonitis (HP) or farmer's lung disease (FLD) was thought to be the major occupational respiratory problem of farmers. In recent years, other acute conditions, particularly organic dust toxic syndrome (ODTS), have been recognized as significant features of the agricultural respiratory disease picture. The differences between HP and ODTS are discussed in this article. A cohort of workers on 90 dairy farms has been under study since 1975. Prevalence of FLD was calculated at 4.2/1,000. Extensive immunologic testing of this group was conducted. Serum antibody reactivity to farmer's lung antigens was related to chronic symptoms of bronchitis and occupational asthma, but not FLD. Serology may be thought of as a measure of exposure, but not FLD.

Agricultural Workers' Diseases↗
PubMed1990

Determinants of restrictive lung function in asbestos-induced pleural fibrosis.

We evaluated whether restrictive lung function among asbestos-exposed individuals with pleural fibrosis was caused by radiographically inapparent parenchymal inflammation and/or parenchymal fibrosis. All 24 study participants were sheet metal workers who were nonsmokers with normal parenchyma on posteroanterior chest radiograph. These subjects had either normal pleura (n = 7), circumscribed plaques (n = 9), or diffuse pleural thickening (n = 8). After controlling for age, years in the trade, and pack-years of smoking, we found that sheet metal workers with diffuse pleural thickening had a lower forced vital capacity (P less than 0.001), total lung capacity (P less than 0.01), and CO-diffusing capacity of the lung (P less than 0.05) than those with normal pleura. Similarly, sheet metal workers with circumscribed plaques were found to have a reduced forced vital capacity; however, because of the small number of study subjects, this difference (regression coefficient = -11.0) was only marginally significant (P = 0.06). Although circumscribed plaque and diffuse pleural thickening were both associated with a lymphocytic alveolitis and a higher prevalence of parenchymal fibrosis on high-resolution computerized tomography (HRCT) scan, neither a lymphocytic alveolitis nor the finding of parenchymal fibrosis on HRCT scan influenced the relationship between pleural fibrosis and restrictive lung function. We conclude that pleural fibrosis is associated with restrictive lung function and abnormally low diffusion that appears to be independent of our measures of parenchymal injury (chest X-ray, bronchoalveolar lavage, and HRCT scan).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗