M3.1 UTILITY OF PULMONARY FUNCTION AND EXERCISE TESTING FOR INTERSTITIAL LUNG DISEASE IN FIELD SETTINGS

M. B. Schenker, M. Stoecklin, R. Lupercio, H. Black, L. Beckett.Department of Public Health Sciences, University of California, Davis, CA, USA

Introduction: Previous studies have found no effect of chronic low level paraquat exposure on spirometry; however, paraquat is known to cause interstitial fibrosis with acute high dose exposure. In addition, chest x rays are insensitive for early interstitial lung disease.

Objective: To assess the utility of measures of restrictive lung disease in a field study of agricultural workers.

Methods: Paraquat exposure and respiratory health was assessed in 340 farm workers (mean (SD) age 37 (10.5) years). We measured single breath diffusion capacity (D_LCO), cardiopulmonary exercise testing (CPET), and spirometry. Data collection was done at farms by technicians following American Thoracic Society guidelines. CPET participants were screened for cardiovascular disease according to American Association of Sports Medicine criteria. Eligible participants were ⩽40 years of age. Results were graded for acceptability according to previously published criteria. Correlations and regression modeling assessed relationships between measures of interstitial lung disease.

Results: The percentage of unacceptable spirometry and D_LCO tests was low. The biggest limitation to CPET was the exclusion of 113 people (33.2%) because of age. The largest correlation was between percentage predicted FVC and alveolar volume (VA_SB). After dichotomising the scales into the lowest fifth percentile, 91% was normal for both measures of restriction and 2% was abnormal on both measures. Comparisons with VO₂ identified no subjects with abnormal …