We studied the relationships between peak expiratory flow (PEF) variability and bronchial responsiveness to methacholine in 117 workers attending the annual compulsory examination (mean age, 38.7 yr +/- 9.5; men, 86.3%). Subjects recorded their highest PEF out of three, every 3 waking hours (i.e., five times a day) for 7 days, each using a newly purchased Vitalograph peak flow meter, and underwent methacholine challenge tests with a maximal cumulative dose of 1,200 micrograms. Those with a FEV1 fall of 15% or more were considered as reactors. The variability of PEF was expressed as the amplitude percent mean, calculated from daily amplitude (highest-lowest reading/mean reading of the day x 100), averaged over 6 days, from the second to the seventh. This index had a continuous distribution, skewed towards the greatest amplitudes, and correlated negatively with FEV1 (r = -0.25, p = 0.01). Subjects with asthma (n = 8) had greater variations. In the 109 nonasthmatics, greater variability was observed in subjects with wheeze apart from colds, breathlessness, or hay fever; the average amplitude was greater in reactors than in nonreactors to methacholine (16.9% versus 9.3%, p less than 0.001). The subjects with excessive PEF variability were all methacholine reactors, but they were only a subgroup of the reactors. These results provide evidence that excessive PEF variability is an indicator of bronchial hyperresponsiveness to methacholine in a population sample.

We assessed the relationship between exposure to silica dust and chronic airflow limitation in an epidemiological survey conducted among pottery workers and controls who were of the same socioeconomic status (average age: 35 y; 78% males). Data were collected by questionnaire for respiratory symptoms, allergy, respiratory history, smoking habits, and occupation. Lung function was measured with a computer-equipped Gauthier spirometer. We excluded subjects with silicosis or doubtful chest x-ray, and two exposure levels were defined. No differences were observed between exposed subjects and controls with respect to respiratory conditions. Mean pulmonary function values for men and women were significantly lower, after adjustment for age, height, and smoking habits, in even indirectly exposed pottery workers, compared with controls. These results suggest that exposure to silica dust is a risk factor for chronic airflow limitation and is independent of radiographic changes.

The aim of this paper was to study respiratory disorders in infancy and childhood as a risk factor for respiratory conditions in adulthood. During the first part of the survey 15,247 adolescents in the Bordeaux area (average age: 16.5 years, boys = 46.6%) filled in a self-administered questionnaire concerning their respiratory history during infancy and childhood, their present symptoms and their smoking habits. Each subject with chronic cough (n = 538) was then matched with two controls (n = 1094) and the parents of these subjects and of their controls were sent a complementary questionnaire. During the second part, 1807 adults (average age: 39.3 years; men = 49.7%) working at Bordeaux University filled in a self-administered questionnaire about their present respiratory symptoms, smoking habits and respiratory symptoms during adolescence. Spirometry was performed in 172 adolescents and 1665 adults. The results of the first part showed a very significant relationship in adolescents between respiratory history during infancy and childhood and current chronic cough even in non-smokers, non-wheezers and non-asthmatics. The second part showed a very significant relationship in adults between respiratory symptoms during adolescence and present respiratory symptoms on the one hand, and a lower pulmonary function on the other, taking wheezing, smoking and asthma into account. In common with many similar studies, we conclude that respiratory disorders in young children may predispose to later disease, and that consequently it might be important to determine appropriate measures to prevent respiratory illness in childhood.

A matched survey of 55 full-time workers probably exposed to asbestos in an electricity-generating power station (exposed group) and of 53 unexposed workers in an automobile plant has been conducted. The asbestos risk in the power station was confirmed by the presence of airborne fibers in the range 0.1--6000 X 10(-9) g/m3 in the air sampled during the survey period and by the presence of FB in the sputa of 32.7% of the workers. The following parameters were significantly related to asbestos exposure in the study group: FB in the sputa, localized rectitude of the diaphragm, pleural thickening, pleural calcification, and the chest pain. Moreover, for all persons studied, gastrointestinal symptoms and recent hoarsening of the voice were significantly related to the number of FB in the sputa.