Prognostic value of acetylcholine challenge test: a prospective study.

Abstract

Cedex, and Lormines, 57703 Hayange, France ABSTRACr Eleven hundred and nine iron mine workers aged 35 to 55 with normal chest radiographs were submitted to a pulmonary examination consisting of a questionnaire, a clinical examination, and pulmonary function testing including an acetylcholine challenge test. A positive response (decrease of FEV, of more than 10%) was observed in 210 subjects (Ace+). The remaining 899 had a negative response (Ace-). Bronchitis, asthma, dyspnoea, and obstructive syndrome were more frequent in the Ace+ group. Five years later, 820 subjects were reexamined: occasional cough and sputum and chronic bronchitis appeared more frequently among subjects without symptoms at the first examination but with a positive acetylcholine challenge test. The obstructive syndrome was more often observed and regressed more rarely in the Ace+ group. The results confirm the use of a test of bronchial hyperreactivity as a means of identifying subjects at risk from chronic obstructive lung disease.The concept that bronchial hyperreactivity was important in the evolution of chronic obstructive lung disease (COLD) was introduced by Dutch investigators.' 2 Pharmacodynamic tests using acetylcholine, metacholine, or histamine may be used to evaluate the degree of hyperreactivity.36 Initial work by Tiffeneau et a13-6 on the ventilatory effect of acetylcholine concerned asthmatic subjects during remission. It is now known, however, that bronchial hyperreactivity may occur not only in asthma but also in other conditions as a response to inhaled irritants and infections. The mechanism of this hyperreactivity is complex and not yet fully understood; nevertheless, it remains a criterion to be taken into account when evaluating the diagnosis and prognosis of COLD, the decrease in forced expiratory volume in one second (FEV,) being correlated with the degree of methacholine reactivity as was pointed out by Barter and Campbell7 and Minette8 in their longitudinal studies of bronchitic patients.In 1973 a recommendation was made by the working group on "functional respiratory tests in

Iron miners ? A ten year follow-up

“…We find, again, in this ten year follow-up study, a high rate of mortality due to lung cancer (SMR = 3.7), confirming the results discussed in our previous papers (23,27). Neither silica levels nor ionizing radiation levels, which were low in these mines (less than 2.1% and 0.07 working levels, respectively), can satisfactorily explain this excess.…”

Standardized challenge testing with pharmacological, physical and sensitizing stimuli in adults

“…Although there is some controversy on this in longitudin~ epidemiological studies [29,30], airway responsiven 's app9~s to be of prognostic significance in prospective clinic~) studies in children [31] as well as in adults [32]. If these fmdings can be confmned in other studies, the prognostic value might become one of the major indications of challenge tests in research and clinical practice.…”

Measurement of bronchial responsiveness by forced oscillation technique in occupational epidemiology

“…The results from the methacholine challenge test for spirometric data were examined using two types of index: 1) Percentage decline in FEV 1 as a qualitative measure of BHR, which is usually defined by a 20% decline in FEV 1 [18]; nevertheless, some authors have suggested that a lower level of change could indicate the presence of BHR [7,19,20]; in the present study, three threshold values were considered: 20, 15 and 10% fall in FEV 1 where ∆FEV 1 % was defined by the following relation: 2) Dose-response slopes were established for each parameter by dividing the previous forced oscillation indices by the cumulative dose of methacholine.…”

“…A decline in respiratory function has been observed among subjects with BHR, suggesting that the latter might be a predisposing factor of bronchopulmonary obstructive disease [5,6]. In a longitudinal study of iron mine workers, PHAM et al [7] observed that the incidence of chronic bronchitis was higher and the decrease in forced expiratory volume in one second/forced vital capacity ratio (FEV 1 /FVC) more marked among hyperreactive subjects. These studies suggest the importance of early detection of BHR in groups exposed to respiratory pollutants.…”