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A cross-sectional study of the respiratory symptoms and pulmonary function of 524 workers who produce man-made mineral fibres was conducted in two fibrous-glass plants in France. An environmental survey was performed in conjunction with epidemiological investigations. The protocol included a questionnaire on smoking habits, occupational history, respiratory symptoms, irritative complaints of eyes, skin, upper airways, a physical examination of the chest, a chest radiograph, and lung function tests (forced expiration, single-breath and steady-state diffusion capacity, single-breath nitrogen washout).The respirable fibre concentration was always below 0.3 fibre/cm3. Exposed workers had slightly more chronic bronchitis, dyspnoea, laryngeal irritation, and nasal congestion, but the excess was not significant. Chest radiograph and lung function abnormalities were not related to the duration of exposure to fibres or resins. An obvious influence of tobacco consumption was found for respiratory symptoms and lung function performance. Lung function in a subgroup of 11 oven workers deviated from predicted values, but this was not statistically significant. [ABSTRACT FROM PUBLISHER]

The main aspects and consequences of tobacco use resulting from a series of field surveys in Romania are reviewed. The proportion of smokers in middle-aged adults is about 10 per cent for women and 40 to 50 per cent for men. Cigarettes are practically the only form of tobacco consumed—cigars are very rarely smoked and pipe-smoking accounts for less than 1 per cent of tobacco use. Less than 10 per cent of smokers use more than 25 cigarettes a day. Age at starting to smoke is low, with a quarter of smokers taking up the habit by the age of 15. Ninety per cent of the smokers admit to inhaling, and about half the men and nearly all the women smoke filter cigarettes. [ABSTRACT FROM PUBLISHER]

In 11 patients with bronchial asthma, lung volumes, FEV, PaO, and lung diffusing capacity (single breath CO method) were measured in status asthmaticus and after recovery. Ventilatory capacity improved following therapy. The improvement was associated with a rise in vital capacity and a fall in residual volume, but the total lung capacity might either decrease, increase or remain unchanged. A decreased value of PaO was found in all patients in status asthmaticus. After treatment PaO increased in all patients. In two of them PaO increased despite the unchanged values of the other parameters of pulmonary function. The improvement of PaO after treatment is considered to be the result of adjustment of perfusion to ventilation. The lung diffusing capacity was below normal values in three patients before treatment. After treatment the diffusing capacity increased in six patients. The diffusion constant, although within the normal range in status asthmaticus, increased after treatment in one and decreased in three other patients. The decreased diffusing capacity in status asthmaticus is the consequence of a reduced effective alveolar volume due to uneven distribution of ventilation. The changes observed in the diffusion constant following corticotherapy are ascribed to a dependence of this constant on the different level of the alveolar volume at which the single breath test is performed. [ABSTRACT FROM PUBLISHER]

In 17 subjects with bronchial asthma and chronic bronchitis measurements of the uneven ventilation using the single breath oxygen test, F.E.V. and V.C. were performed before and after acetylcholine or allergen nebulization. An increase of the alveolar slope was noticed in five out of the seven patients with induced bronchospasm and a decrease in the remaining two. In two other subjects moderate dyspnoea not reflected by spirographic tests was accompanied by a definite increase of the N gradient. One patient experienced a severe asthmatic attack after acetylcholine without significant increase of the N gradient. In the last seven subjects the spirographic tests were not impaired but the N gradient rose to a significant level in three. The various implications of these results are discussed. In one subject the alveolar nitrogen concentration decreased after acetylcholine with a concomitant increase in the residual volume. This finding was assumed to be the result of either a failure of inspired oxygen to mix with alveolar nitrogen or a decreased available lung space. [ABSTRACT FROM PUBLISHER]

Abstract Background Currently, there is much interest in measuring fractional exhaled nitric oxide (FENO) in populations. We evaluated the reproducibility of FENO in healthy subjects and determined the number of subjects necessary to carry out a longitudinal survey of FENO in a population containing smokers and non-smokers, based on the assessed reproducibility. Methods The reproducibility of FENO was examined in 18 healthy smokers and 21 non-smokers. FENO was assessed once at 9 AM on five consecutive days; in the last day this measurement was repeated at 2 PM. Respiratory symptoms and medical history were assessed by questionnaire. The within- and between-session repeatability of FENO and log-transformed FENO was described. The power of a longitudinal study based on a relative increase in FENO was estimated using a bilateral t-test of the log-transformed FENO using the between-session variance of the assay. Results FENO measurements were highly reproducible throughout the study. FENO was significantly higher in males than females regardless of smoking status. FENO was positively associated with height (p < 0.001), gender (p < 0.034), smoking (p < 0.0001) and percent FEV1/FVC (p < 0.001) but not with age (p = 0.987). The between-session standard deviation was roughly constant on the log scale. Assuming the between-session standard deviation is equal to its longitudinal equivalent, either 111 or 29 subjects would be necessary to achieve an 80% power in detecting a 3% or a 10% increase in FENO respectively. Conclusion The good reproducibility of FENO is not influenced by gender or smoking habits. In a well controlled, longitudinal study it should allow detecting even small increases in FENO with a reasonable population size.

Background: Currently, there is much interest in measuring fractional exhaled nitric oxide (FENO) in populations. We evaluated the reproducibility of FENO in healthy subjects and determined the number of subjects necessary to carry out a longitudinal survey of FENO in a population containing smokers and non-smokers, based on the assessed reproducibility.Methods: The reproducibility of FENO was examined in 18 healthy smokers and 21 non-smokers. FENO was assessed once at 9 AM on five consecutive days; in the last day this measurement was repeated at 2 PM. Respiratory symptoms and medical history were assessed by questionnaire. The within- and between-session repeatability of FENO and log-transformed FENO was described. The power of a longitudinal study based on a relative increase in FENO was estimated using a bilateral t-test of the log-transformed FENO using the between-session variance of the assay.Results: FENO measurements were highly reproducible throughout the study. FENO was significantly higher in males than females regardless of smoking status. FENO was positively associated with height (p < 0.001), gender (p < 0.034), smoking (p < 0.0001) and percent FEV1/FVC (p < 0.001) but not with age (p = 0.987). The between-session standard deviation was roughly constant on the log scale. Assuming the between-session standard deviation is equal to its longitudinal equivalent, either 111 or 29 subjects would be necessary to achieve an 80% power in detecting a 3% or a 10% increase in FENO respectively.Conclusion: The good reproducibility of FENO is not influenced by gender or smoking habits. In a well controlled, longitudinal study it should allow detecting even small increases in FENO with a reasonable population size. [ABSTRACT FROM AUTHOR]