Department of Public Health Sciences

Pulmonary function and exercise-associated changes with chronic low-level paraquat exposure

Schenker, Marc B, Maria Stoecklin, Kiyoung Lee, Rafael Lupercio, R Jorge Zeballos, Paul Enright, Tamara Hennessy and Laurel A Beckett

Am J Respir Crit Care Med. 2004. 170(7):773-9.

The present study was undertaken to test the hypothesis that chronic, low-level paraquat exposure causes restrictive lung function with gas transfer impairment. Three hundred thirty-eight Costa Rican farm workers from banana, coffee, and palm oil farms completed a questionnaire, spirometry, and a test of single-breath carbon monoxide diffusing capacity. Subjects 40 years of age or older, without other medical risk factors, completed maximal cardiopulmonary exercise tests. Most (66.6%) were paraquat handlers; 24.8% of handlers and 27.3% of nonhandlers reported current cigarette smoking. In linear regression models, cumulative paraquat exposure was not an independent predictor of VA, carbon monoxide diffusing capacity, peak oxygen uptake, FVC, or oxygen pulse peak. However, the ventilatory equivalent for CO(2), although within normal range, was significantly higher with increased cumulative paraquat exposure. Oxygen desaturation greater than 5% from rest to peak exercise had an odds ratio of 1.7 (95% confidence interval = 0.9-3.0) with the cumulative paraquat exposure index in models adjusted for age, weight, and smoking status. The association of paraquat exposure with ventilatory equivalent and oxygen desaturation suggests that paraquat may be associated with subclinical gas exchange abnormalities, but overall these findings are consistent with no clinically significant increases in interstitial thickening or restrictive lung disease among this population.

Keywords: Adolescent; Adult; Agricultural Workers' Diseases/*chemically induced/diagnosis/physiopathology; Agrochemicals/poisoning; Chronic Disease; Coffee; Costa Rica; Cross-Sectional Studies; Exercise Test; Herbicides/*poisoning; Humans; Linear Models; Logistic Models; Middle Aged; Musa; Occupational Exposure/adverse effects/analysis; Paraquat/*poisoning; Plant Oils; Predictive Value of Tests; Pulmonary Fibrosis/*chemically induced/diagnosis/physiopathology; Questionnaires; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.; Respiratory Function Tests



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