Am. J. Respir. Crit. Care Med., Vol 150, No. 5, 11 1994, 1243-1249.
Longitudinal changes in lung function among asbestos-exposed workers
DA Schwartz, CS Davis, JA Merchant, WB Bunn, JR Galvin, DS Van Fossen, CS Dayton and GW Hunninghake
Department of Internal Medicine, Department of Veterans Administration Medical Center, Iowa City, Iowa.
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)
