Lung Function Disorders Research Articles

A one-year follow-up study of patients survived after ALI / ARDS caused by influenza A / H1N1

Summary. The study analyzed long-term consequences of acute lung injury / acute respiratory distress syndrome (ALI / ARDS) caused by influenza A / H1N1 and effects of long-term treatment with N-acetylcysteine (NAC) on clinical and functional recovery of survived patients. This was an open, prospective, 12-month study involved 22 patients survived from ALI / ARDS caused by influenza A / H1N1. The patients' lung function, arterial blood gases, physical tolerance in 6-min walking test (6MWT) and computed tomography (CT) of the lungs were monitored in 3, 6, and 12 months after discharge. During the follow-up, all lung function parameters improved: FVC, TLC, and DLCO increased by 28.7 %, 17.5 % and 31.4 %, respectively (p < 0.05 for all). In a year after discharge, DLCO < 80 %pred. was found in 23 % of patients. At 12 months, the mean 6MWT distance increased from 454 Ѓ} 37 to 568 Ѓ} 47 m (р = 0.002). Significant improvement was noted in CT findings and 41% of patients had quite normal lung CT at 12 months. Therapy with NAC (n = 11) has led to more rapid improvement in DLCO (76.3 Ѓ} 11.8 %pred. vs 63.0 Ѓ} 10.6 %pred. in controls; р = 0.012) and 6MWT distance (533 Ѓ} 42 m vs 490 Ѓ} 46 m, respectively; р = 0.033) at 3 months. Therefore, patients survived from ALI / ARDS caused by influenza A / H1N1 demonstrated significant recovery of lung function, gas exchange, lung CT picture and physical tolerance but in some of them, persistent disorders of lung function (mainly in DLCO) and lung CT have been still found at 1 year after discharge. Treatment with NAC allowed more rapid improvement in DLCO and exercise tolerance.

Patients with gastroesophageal reflux disease and respiratory manifestations do not present lung function disorders during cardiopulmonary exercise test

Gastroesophageal reflux disease (GERD) has been associated with a variety of pulmonary manifestations, but it is unclear if gastroesophageal reflux causes any abnormality in pulmonary function. Cardiopulmonary exercise test (CPET) is a specialized method that is used to evaluate respiratory function during exercise. The aim of this study was to reveal any abnormality of pulmonary function in patients with GERD and respiratory symptoms. We evaluated 34 patients with GERD (24 men and 10 women, aged 21-63) and extraesophageal respiratory symptoms (wheezing and/or cough) before therapy and after a 12-week treatment with double dose of omeprazole. No patient presented abnormal spirometry. CPET was performed in all the patients at baseline and after completion of the 12-week treatment. CPET parameters including VO(2) rest, VO(2) max, VCO(2) rest, VCO(2) max, O(2)-puls rest, O(2)-puls max, HR (heart rate) rest, HRmax, PETCO(2) rest, PETCO(2) max, and VE/VCO(2) slope were recorded pretreatment and posttreatment. Twenty-four patients (70.6%) had esophagitis (grade A-D), 16 patients had hiatal hernia (47.1%), and 13 patients (38.2%) tested positive for Helicobacter pylori. All of the patients completed the CPET. No one presented shortness of breath or respiratory symptoms. CPET parameters were within normal limits in all of the patients. Twenty-eight patients were reevaluated. No improvement in any CPET parameter posttreatment was observed despite remission of esophageal and extraesophageal respiratory symptoms in all patients. No statistically significant difference was observed pretreatment and posttreatment between the patients older and younger than 40 years, smokers and nonsmokers, Hp(+) and Hp(-) patients, and those with and without hiatal hernia and esophagitis. The patients with GERD and respiratory manifestations and normal spirometry present no pulmonary dysfunction during CPET. No alterations in CPET values posttreatment or differences in CPET values according to age, smoking, Hp status, presence of esophagitis, or hiatal hernia were observed.

Involvement of A1adenosine receptors in altered vascular responses and inflammation in an allergic mouse model of asthma

Poor lung function and respiratory disorders like asthma have a positive correlation with the development of adverse cardiovascular events. Increased adenosine levels are associated with lung inflammation that could lead to altered vascular responses and systemic inflammation. We hypothesized that asthmatic lung inflammation has systemic effects through A(1) adenosine receptors (A(1)AR) and investigated the effects of aerosolized adenosine on vascular reactivity and inflammation, using A(1)AR knockout (A(1)KO) and corresponding wild-type (A(1)WT) mice that were divided into three experimental groups each: control (CON), allergen sensitized and challenged (SEN), and SEN + aerosolized adenosine (SEN + AD). Animals were sensitized with ragweed (200 microg ip; days 1 and 6), followed by 1% ragweed aerosol challenges (days 11 to 13). On day 14, the SEN + AD groups received one adenosine aerosol challenge (6 mg/ml) for 2 min, and aortae were collected on day 15. 5'-N-ethylcarboxamidoadenosine (NECA; nonselective adenosine analog) induced concentration-dependent aortic relaxation in the A(1)WT CON group, which was impaired in the A(1)WT SEN and SEN + AD groups. All groups of A(1)KO mice showed similar (no significant difference) concentration-dependent relaxation to NECA. The A(1)WT SEN and SEN + AD groups had a significantly higher contraction to selective A(1) agonist 2-chloro-N(6)-cyclopentyladenosine (CCPA) compared with the CON group. Western blot data showed that aortic A(1)AR expression was significantly increased in WT SEN and SEN + AD mice compared with CON mice. Gene expression of ICAM-1 and IL-5 was significantly increased in allergic A(1)WT aorta and were undetected in the A(1)KO groups. A(1)WT allergic mice had significantly higher airway hyperresponsiveness (enhanced pause) to NECA, with adenosine aerosol further enhancing it. In conclusion, allergic A(1)WT mice showed altered vascular reactivity, increased airway hyperresponsiveness, and systemic inflammation. These data suggest that A(1)AR is proinflammatory systemically in this model of allergic asthma.

Conservative treatment in patients with severe congenital scoliosis: a presentation of three cases

BACKGROUND: In view of the very limited data about conservative treatment of patients with congenital scoliosis (CS) available, early surgery is suggested already in mild cases with formation failures in the first three years of life. It is common sense that patients with failures of segmentation will not benefit from conservative treatment at all and the same applies to failures of formation with curves of > 50 degrees in infancy. MATERIALS AND METHODS: Two patients with rib synostosis denied surgery before entering the pubertal growth spurt. These patients have been treated conservatively with braces and Scoliosis In-Patient Rehabilitation (SIR) and now are beyond the pubertal growth spurt. One patient with a formation failure and a curve of > 50 degrees lumbar has been treated with the help of braces and physiotherapy from 1.6 years on and is still under treatment now at the age of 15 years. RESULTS: Severe decompensation was prevented in the two patients with failure of segmentation, however a severe thoracic deformity is evident with underdeveloped lung function and severe restrictive ventilation disorder. The patient with failure of formation is well developed now without cosmetic or physical complaints although his curve progressed at the end of the growth spurt due to mal-compliance. CONCLUSIONS: Failures of segmentation should be advised to have surgery before entering the pubertal growth spurt. In case they deny, conservative treatment can at least in part be beneficial. For patients with failures of formation conservative treatment should be suggested in the first place because long-term outcomes of early surgery beyond pubertal growth spurt are not yet revealed.

Work conditions and development of respiratory pathology in meat processing factory workers

To study a rate and a character of respiratory and allergic pathology in subjects engaged in industrial production of sausages and other meat foods, this prospective longitudinal trial was performed in workers of one of the leading meat processing factories at Moscow. The trial involved 110 subjects (53 females and 57 males) aged 20 to 73 yrs with mean length of service of 11.7 yrs. There were 56 current smokers (50.9 %) with smoking history of 21.5 pack-yrs in average. The authors used the specialized SWORD questionnaire, clinical and ENT examination, spirometry and bronchodilating test with Ventolin, peak flowmetry to detect specific bronchial hyperreactivity, measured serum cytokine levels (TNF-α, IL-4, IL-6). According to the questionnaire results, 38 workers (34.5 %) had respiratory symptoms (cough, sputum production, breathlessness, asthma attacks) and 17 workers (15.5 %) had allergic symptoms (skin itch, urticaria, tearing, eyelid itch and hyperemia, rhinorrea, nasal congestion). Clinical respiratory signs were found only in 13 (11.8 %) of the workers. Lung function disorders were found in 40 (36.4 %) of the workers. The degree of FEV 1 and PEF decrease significantly correlated with the length of service ( r = –0.26 and r = –0.29, respectively). Av inverse correlation was found between FEV 1 and cytokine levels ( r = –0.3; r = –0.31 and r = –0.26 for IL-4, IL-6, and TNF-α, respectively). Therefore, the results show the actuality of healthcare problems in subjects involved in meat processing.

Lungenfunktion nach Bestrahlung bei pädiatrisch-onkologischen Patienten

Lung function tests were performed in 22 children and juveniles who had received radiotherapy to the lungs, an average of 9.5 years previously, for tumour (14 with Hodgkin's disease [aged 7-22 years], 4 with malignant non-Hodgkin lymphoma [aged 6-14 years], 3 with Wilms tumour [4-6 years], and one with Ewing's sarcoma [aged 16 years]). All three patients who, as young children, had had radiotherapy to both lungs because of a Wilms tumour with multiple lung metastases had restrictive disorders of lung function. Four of 12 after treatment of Hodgkin's disease and one of two after malignant non-Hodgkin lymphoma and extensive thoracic irradiation developed a restrictive disorder of pulmonary function. But all four patients who had irradiation restricted to the mediastinum had normal lung functions.

An experimentally inducedChlamydiasuis infection in pigs results in severe lung function disorders and pulmonary inflammation

This study was aimed at evaluating the pathophysiology of pulmonary dysfunctions and inflammatory consequences of an acute respiratory chlamydial infection induced experimentally in conventionally raised pigs (aged 39-44 days). Eight animals were exposed to Chlamydia suis (C. suis) and four non-infected animals served as controls. The total observation period was from seven days before challenge to seven days post exposure. While non-infected control pigs did not exhibit any clinical symptoms, animals exposed to C. suis developed fever and were severely respiratory distressed within the first week after exposure. After C. suis infection, pulmonary dysfunctions were characterised by a significant decrease in the diffusion capacity of the lung (i.e. transfer factor of the lung for carbon monoxide; TL CO), a significant increase in the functional residual capacity (FRC), and significant changes in the pattern of ventilation (respiratory rate increased while the tidal volume decreased). In exhaled breath condensate (EBC), leukotriene B(4) (LTB(4)) and interleukin 6 (IL-6) showed a tendency to increase after infection. In the broncho-alveolar lavage fluid (BALF) of C. suis infected pigs, the activity of matrix metalloprotease 9 (MMP-9) was found to be increased compared to controls. BALF cytology was characterised by increased numbers of granulocytes and activated lymphocytes. Pulmonary inflammation in infected pigs was confirmed by post mortem histology. A prominent dissemination of chlamydial bodies in the lung was accompanied by an influx of macrophages, granulocytes and activated T-cells. Data obtained in this study provide new insight into the pathogenesis of acute respiratory chlamydial infections in pigs.

Dose–response relationships between occupational exposure to potash, diesel exhaust and nitrogen oxides and lung function: cross-sectional and longitudinal study in two salt mines

Several studies have shown that underground salt miners may have an increased incidence of chest symptoms and sometimes decreased lung function. Miners of two salt mines were investigated to evaluate relationships between the lung function and the workplace exposure. The effect of nitrogen monoxide (NO) and nitrogen dioxide (NO(2)) was investigated in view of the recent debate on European occupational exposure limits. A total of 410/463 miners (mine A/mine B) were examined cross-sectional and 75/64% of the first cohort were examined after a 5-year period. Exposure was measured by personal sampling. Personal lifetime exposure doses of salt dust, diesel exhaust, NO(2) and NO were calculated for all miners. Dose-response relationships were calculated by multiple regression analysis. Each exposure component acted as an indicator for the complex exposure. Exposure response relationships were shown in the cross-sectional and longitudinal investigations in both mines. In the 5-year period, the adjusted (age, smoking, etc.) effect of the exposure indicators resulted in a mean decrease of FEV(1) between -18 ml/year (mine A) and -10 ml/year (mine B). The personal concentrations related to this effect were 12.6/7.1 mg/m(3) inhalable dust, 2.4/0.8 mg/m(3) respirable dust, 0.09/0.09 mg/m(3) diesel exhaust, 0.4/0.5 ppm NO(2) and 1.7/1.4 ppm NO (mine A/B). Exposure was related to symptoms of chronic bronchitis only in mine B. The effects found in both mines indicate that the mixed exposure can cause lung function disorders in salt miners exposed over a long time. Because of the high correlation of the concentrations it was not possible to determine the effects of a single exposure component separately or to recommend a specific occupational exposure limit. However, possible maximum effects associated with the mixed exposure can be evaluated in the ranges of concentrations of the individual substances in the mines.

Lung involvement in systemic connective tissue diseases

Systemic connective tissue diseases (SCTD) are chronic inflammatory autoimmune disorders of unknown cause that can involve different organs and systems. Their course and prognosis are different. All of them can, more or less, involve the respiratory sistem. The aim of this study was to find out the frequency of respiratory simptoms, lung function disorders, radiography and high-resolution computerized tomography (HRCT) abnormalities, and their correlation with the duration of the disease and the applied treatment. In 47 non-randomised consecutive patients standard chest radiography, HRCT, and lung function tests were done. Hypoxemia was present in nine of the patients with respiratory simptoms (20%). In all of them chest radiography was normal. In five of these patients lung fibrosis was established using HRCT. Half of all the patients with SCTD had simptoms of lung involment. Lung function tests disorders of various degrees were found in 40% of the patients. The outcome and the degree of lung functin disorders were neither in correlation with the duration of SCTD nor with therapy used (p > 0.05 Spearmans Ro). Pulmonary fibrosis occures in about 10% of the patients with SCTD, and possibly not due to the applied treatment regimens. Hypoxemia could be a sing of existing pulmonary fibrosis in the absence of disorders on standard chest radiography.

Congenital scoliosis - presentation of three severe cases treated conservatively.

UNLABELLED In view of the very limited data about conservative treatment of patients with congenital scoliosis (CS) available, early surgery is suggested already in mild cases with formation failures in the first three years of life. It is common sense that patients with failures of segmentation will not benefit from conservative treatment at all and the same applies to failures of formation with curves of >50 degrees in infancy. MATERIALS AND METHODS Two patients with rib synostosis denied surgery before entering the pubertal growth spurt. These patients have been treated conservatively with braces and Scoliosis In-Patient Rehabilitation (SIR) and now are beyond the pubertal growth spurt. One patient with a formation failure and a curve of >50 degrees lumbar has been treated with the help of braces and physiotherapy from 1.6 years on and is still under treatment now at the age of 15 years. RESULTS Severe decompensation was prevented in the two patients with failure of segmentation, however a severe thoracic deformity is evident with underdeveloped lung function and severe restrictive ventilation disorder. The patient with failure of formation is well developed, now without cosmetic or physical complaints although his curve progressed at the end of the growth spurt due to final mal-compliance. CONCLUSIONS Failures of segmentation should be advised to have surgery before entering the pubertal growth spurt. In case they deny, conservative treatment can at least in part be beneficial. For patients with failures of formation conservative treatment should be suggested in the first place because long-term outcomes of early surgery beyond pubertal growth spurt are not yet revealed.

Role of lung inflammatory mediators as a cause of training-induced lung function changes in runners

Objective This study was designed to assess whether one year endurance training affects lung inflammatory mediators release and airway cells composition, and the possible relationship with lung function disorders in healthy runners. Materials and Methods In 10 healthy endurance runners, sputum samples were obtained at rest and 2 h after an exercise session at 80% of athlete's maximal aerobic speed. Inflammatory cells and metabolites were assessed and respiratory function was analysed either after exercise, or at rest through spirometry. The tests were conducted on 3 different occasions: during basic endurance training, pre-competitive and competitive periods. Results At rest, sputum showed prevalence of macrophages over neutrophils; after exercise, increased neutrophil counts were found in the two last periods of the sport season ( P < 0.05). A significant increase in macrophage counts was observed during the pre-competitive period. Sputum supernatant revealed significant increase in histamine, IL-8, LTB 4, and LTE 4 concentrations during the competitive period. Conclusion This study does not provide significant evidence that one year endurance training may be detrimental for respiratory health in runners. Indeed, in spite of significant changes in airway cells and markers of lung inflammation, no symptoms or changes in lung function were found.

Lung diseases in called-up aged patients

A problem of lung pathology in called up aged men notwithstanding its great significance has not been studied completely. Four hundred outpatients of the Saratov Pulmonary Center were recruited to this investigation. Of them, 243, or 60.7 %, patients of called up age and younger were admitted by military registration offices. Sixty patients (15 %) more of the same age were admitted to the clinic by city outpatient departments for treatment. Asthma prevailed at the nosology structure of lung diseases in the called up aged patients (90.1 %); chronic obstructive bronchitis (COB) (4.5 %) and chronic non obstructive bronchitis (CNOB) (2.9 %) were rarer. Most of the patients (91.4 %) were in stable condition. Of the patients admitted by the outpatient departments, asthma and COB also predominated but 63.4 % of them had acute exacerbations. Such situation apparently reflects different motivations of admission to a hospital in these patient groups (expert evaluation or conventional diagnosis and treatment). Preliminary diagnosis of the military registration offices was mostly confirmed. The diagnosis was changed in 10 % of the cases demonstrating under estimation or overestimation of asthma and COB, 30 % of the patients needed the diagnosis to be verified. The collective "portrait" of a called up aged man is the following: a student of 17 years old with stable intermittent or mild persistent asthma, rarer mild COB, with no lung function disorders, low blood eosinophil number, regular pollinosis, not requiring therapy.

Особенности функциональных нарушений бронхолегочной системы у рабочих угольной промышленности

Особенности функциональных нарушений бронхолегочной системы у рабочих угольной промышленности

Pulmonary function impairment in children following hematopoietic stem cell transplantation

Deterioration of pulmonary function after hematopoietic stem cell transplantation (SCT) is a well-known late effect of this treatment, but the course of pulmonary function over time is less clear. The aim of our study was to establish both the prevalence and course of pulmonary function abnormalities in children following SCT. Thirty-nine of 106 patients, who visited a post-SCT late effects clinic and who underwent a pulmonary function test (PFT) both before and at least twice after SCT were included in this study. Forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), total lung capacity (TLC), and total lung diffusion capacity (TLCO) were determined and recorded as percentage predicted for age, sex, and length matched controls. Values of less than 80% of predicted were considered abnormal. Change in PFT parameters over time was determined by comparing the mean PFT parameter in our group at three different time points: pre-SCT, < or =1 year post-SCT (SCTpost1) and >1 year post-SCT (SCTpost2). After SCT restrictive and/or diffusion abnormalities are most prevalent (45% and 76% at SCTpost1, respectively). A significant decrease of TLC (-9.7%) and TLCO (-20.3%) was observed during the first year after SCT, with improvement over time, but no normalization. Obstructive lung disease was less common (6% at SCTpost1). Clinical signs of lung function impairment were rare. Restrictive and diffusion lung function disorders are common after SCT. They improve over time but do not normalize. As only a few patients with pulmonary function abnormalities had clinical signs of lung function impairment, the clinical relevance of performing long-term follow-up of PFT is questionable.

Further evidence for the role of genes on chromosome 2 and chromosome 5 in the inheritance of pulmonary function.

The spirometric measurements FEV1, FVC, and the ratio FEV1/FVC are used in the diagnosis of lung function disorders. Therefore, understanding the genetics underlying these spirometric measurements will increase our knowledge of the genetics of pulmonary function. FEV1 and FVC were measured on 264 members of 26 Utah Genetic Reference pedigrees, originally collected for the Centre d'Etude du Polymorphisme Humain genetic mapping project. Using segregation analysis, we inferred major locus inheritance of the FEV1/FVC ratio, although we could not distinguish between a dominant or recessive mode of inheritance. No evidence of major locus inheritance was found for either FEV1 or FVC. Suggestive evidence of linkage for the ratio FEV1/FVC was found on chromosome 2 (heterogeneity lod = 2.36, dominant model) and chromosome 5 (heterogeneity lod = 2.23, recessive model), replicating linkages from other studies. In addition, nonparametric variance component linkage analysis showed linkage of FEV1/FVC in both of these regions, providing further support to the results. No nonparametric lod scores over 1.5 were obtained for either FEV1 or FVC.

Late sequaela of primary post-traumatic ARDS

Post-traumatic lung injuries with consecutive ALI and ARDS are frequent injuries in trauma populations. There is only a small body of literature dealing with late sequaela of ALI and ARDS. To evaluate the long-term disability and disorders of lung function in these patients, we initiated a prospective, nonrandomised study.

Veterinary practice and occupational health

Summary The prevalence of allergy, lung function disorders, and bronchial hyperreactivity was studied in 102 Dutch veterinarians, subdivided into five professional groups (predominantly working with either swine, cattle, poultry, companion animals, or as a non‐practitioner). The mean age of the participants was 43 years; 6 participants were females. Twenty‐two per cent of the participants were overweight, and relatively more non‐practitioners than practitioners were overweight. Approximately 23% of the vets reported complaints of prolonged fatigue. The data suggest a relationship between complaints of prolonged fatigue and a more than average number of daily working hours. Only a small proportion of vets were sensitized against several allergens. There were no significant differences in prevalence of distinct lung function disorders or bronchial hyperreactivity between professional groups. It is hypothesized that the respiratory complaints (chronic coughing, chronic phlegm production, stuffed nose, sneezi...

Veterinary practice and occupational health. An epidemiological study of several professional groups of Dutch veterinarians. I. General physical examination and prevalence of allergy, lung function disorders, and bronchial hyperreactivity.

The prevalence of allergy, lung function disorders, and bronchial hyperreactivity was studied in 102 Dutch veterinarians, subdivided into five professional groups (predominantly working with either swine, cattle, poultry, companion animals, or as a non-practitioner). The mean age of the participants was 43 years; 6 participants were females. Twenty-two per cent of the participants were overweight, and relatively more non-practitioners than practitioners were overweight. Approximately 23% of the vets reported complaints of prolonged fatigue. The data suggest a relationship between complaints of prolonged fatigue and a more than average number of daily working hours. Only a small proportion of vets were sensitized against several allergens. There were no significant differences in prevalence of distinct lung function disorders or bronchial hyperreactivity between professional groups. It is hypothesized that the respiratory complaints (chronic coughing, chronic phlegm production, stuffed nose, sneezing) reported by the vets predominantly working in swine and/or poultry practice could be caused by irritation and/or inflammation of the first part of the trachea-bronchial tree that has no measurable and permanent consequences for changes in lung function or increased bronchial hyperreactivity. The results of a skin test against allergens and determination of allergen-specific IgE in blood indicated that the respiratory complaints were probably not related to allergy against the panel of allergens tested.

A follow-up study on the relationship between thorium lung burden and health effects on miners (1982-91)

The results of an investigation (1982-91) on the natural thorium lung burden and its health effects on miners in the Baiyan Obo mine are reported. An electrostatic collection system was used to measure the exhaled thoron activity. Measurements of exhaled thoron activity were carried out on 588 miners (985 measurements) who had inhaled thorium-containing dusts. Exhaled thoron activity was also determined on 124 persons (124 measurements), who had not inhaled thorium-containing dusts. The average thorium lung burdens of the 588 miners and the 124 controls were 0.85 Bq and 0.15 Bq, respectively. Of the 588 miners, 7 had a thorium lung burden higher than 3.7 Bq, 5 had a thorium lung burden higher than 4.44 Bq and 1 miner had the highest thorium lung burden of 5.56 Bq. In about 20% of these miners the thorium lung burden was 0.74 Bq. There was no definite increase in the incidence of lung cancers in more than 2000 miners who had inhaled thorium dusts and thoron daughters in the period 1958-90. Of the miners who had inhaled thorium dusts, there was a significant increase in the incidence of respiratory symptoms, lung function disorders and pneumoconiosis stage 0+ and stage 1. Based on the results of animal experiments and the low percentage of thorium in the dust, the authors suggest that disorders of the respiratory tract were due mainly to other chemical components in the dust, such as SiO2 and other chemical elements. The role of thorium is negligible. The average air thorium dust concentrations in the main workshops and the average thorium lung burden of the thorium dust-inhaling miners were lower by a factor of 20 and 3 respectively in 1991 compared with 1983.

Interfering factors to sensitivity and specificity of bronchial reactivity in children

Bronchial reactivity to carbachol, estimated by the PD65, the provocation dose of inhaled carbachol inducing a 65% increase of baseline respiratory resistance, was measured in 355 asthmatic children (age 8.7 +/- 2.6 years) and 149 healthy children (age 11.8 +/- 2.3 years). The frequency distribution of PD65 showed apart from 2 minima at 480 micrograms and 960 micrograms 2 significant peaks at 240 micrograms (p = 0.003) and 1200 micrograms (p = 0.01) to carbachol, reflecting a hyperreactive class (PD65 < 480 micrograms), an intermediate class (481 micrograms < PD65 < 960 micrograms) and a normo-reactive class (PD65 > 961 micrograms). The intermediate class is characterised by a considerable overlap between "health" and "disease". However, taking into account the degree of air pollution in which healthy children are living (best related factor to specificity) and the type of initial lung function disorder in asthmatic children, (the MEF50 to be the best related factor for specificity), weighed specificity and sensitivity improved from 64 to 88%. Evaluating bronchial responsiveness in children, such interfering factors should be strongly considered.