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Lung function reference values in Chinese children and adolescents in Hong Kong. II. Prediction equations for plethysmographic lung volumes.

As part of a comprehensive evaluation of lung function in Hong Kong Chinese children and adolescents, over a thousand healthy subjects aged 7-19 yr from seven schools were recruited for lung function testing that included spirometry and, in many cases, lung subdivision measurements. Lung function tests were performed using SensorMedics Automated Body Plethysmograph according to published standards. Of these, 551 subjects (219 males), aged 8-19 yr, had satisfactory lung subdivision indices recorded. Analysis for the values of lung subdivisions including total lung capacity (TLC), residual volume (RV), and functional residual capacity (FRC) demonstrated that standing height and sitting height were the best predictors of lung volumes. After allowing for standing height or sitting height in the regression models for lung volumes, age at examination was the second best parameter, although its inclusion into the equations contributed to less than 1% of explained variance for boys and 3% for girls. These are the first reported data in international literature on reference values for lung subdivisions in Chinese children and adolescents.

Adolescent↗

[Prospective lung function determination using an electronic miniature spirometer for detection of acute obstructive respiratory changes in diving students during occupational diving training].

BACKGROUND: Changes in lung function have been shown in experienced divers. The purpose of this study was to measure the pulmonary function of diving trainees who were not exposed to a hyperbaric environment before. METHODS: We measured the lung function in a sample of fifteen randomized selected young healthy non-smoking diving trainees parallel to fourteen open water dives. Five subjects used common compressed air diving apparatuses (breathing gas: 21% O2/78% N2) and ten subjects used closed circuit diving apparatuses (breathing gas compositions depended to the diving depths; 24 m: 60% O2/40% N2, 42 m: 40% O2/60% N2, 54 m: 32.5% O2/67.5% N2). The values (FVC, FEV1, PEF, MEF 25, MEF 50, MEF 75) were obtained by an electronic miniature-spirometer directly before descent, upon surfacing, and after one hour and four hours. RESULTS: The lung function values of the subjects who used compressed air showed no relevant impairment of lung function after the diving exposures. Significant (p < 0.05) post dive lung function reductions (FVC, FEV1, PEF, MEF 25, MEF 50, MEF 75), were evident in subjects using closed circuit diving apparatuses, after deep dives and shallow water dives. CONCLUSIONS: The decreased lung function of the used diving apparatuses. The impaired lung functions in subjects using closed circuit diving apparatuses may be induced by a subclinical lung edema generated by pressure differences between breathing gas and thorax tissues as well as the influences of soda-lime dust. Compared to compressed air diving the significantly increased oxygen partial pressures (p < 0.001) in closed circuit diving apparatuses may be an additional reason for the reversible airway obstructions.

Adult↗

Influences of asthma and household environment on lung function in children and adolescents: the third national health and nutrition examination survey.

The authors examined influences of asthma and household environment (passive smoking, use of a gas stove, and having a dog or cat) on five measures of spirometric lung function among 8- to 16-year-old subjects, as measured cross-sectionally in the Third National Health and Nutrition Examination Survey (NHANES III) (1988-1994). In regression models, independent variables included asthma status, household environmental factors, age, and anthropometric measurements. Regression analyses were weighted by the NHANES III examination sample weighting factor, and results were adjusted for clustering in the sampling design. There were distinct sex differences in the results. In girls, lung function was lowest among active asthmatics taking prescription respiratory medicine, whereas lung function in other active and inactive asthmatics did not differ greatly from that in nonasthmatics. In boys, however, all groups of asthmatics had substantially lower lung function than nonasthmatics. Differences in lung function between active asthmatics and nonasthmatics were stable with increasing age. However, the lung function of inactive asthmatic girls and boys returned to and diverged from nonasthmatics' levels, respectively. In asthmatic girls, passive smoking was associated with reduced lung function; having a dog or cat was associated with increased lung function; and gas stove use was associated with reduced lung function among subjects not taking prescription respiratory medicine.

Adolescent↗

[Lung function and normal values].

Interindividual derived predicted values of lung function are not suitable for detection of early changes of lung function. Intraindividual values show variability, which should be considered. Many of the very common obstructive lung diseases start with small variations of the individual values of lung function, long time before clinical manifestation takes place. Followup of the most useful measurements (FEV1, MEF 50%, Rt und IGV%) show reliable early changes, important for preventive therapeutic intervention. Strong variability of the individual values argue for hyperreagibility of the airways, even as a risk factor for manifestation of obstructive airway diseases.

Adult↗

[Correlation of roentgen picture and lung function testing within the scope of silicosis evaluation].

The chest roentgenograms codified according to the 1980 ILO classification and the lung function tests of 100 persons with silicosis have been compared with each other. The results show that, with a higher degree of dissemination and a growing size of nodes, there is a statistically significant tendency to increasing gravity of pathological results of resistance and the arterial blood gas analysis. A correlation between the degree of dissemination and the size of nodes to other lung function parameters (vital capacity, intrathoracic gas volume) cannot be finally established. Furthermore, neither coding as category B nor the employment of the symbols em (emphysema) and tb (tuberculosis) allow conclusions to be drawn about the results of lung function tests. The poor correlation is caused on one hand by the insufficient description of the morphological parameters important for function, due to the restricted classification. On the other hand there is little correlation between chest roentgenogram and lung function, as lung function in anthracosis is essentially influenced by obstructive bronchitis, which has only a loose connection with silicosis.--Lung function must be the central point in the process of forming an opinion. Chest roentgenograms are important for clarifying the causes of pathological changes and allow a simple observation of progress.

Airway Resistance↗

A multivariate study of some lung function tests at different age groups in healthy Indian males.

Considerable attempts have been made to study the changes in lung function in man in different age groups using univariate statistical techniques in which the lung function tests were assumed to be independent of each other. Actually the lung function tests are well correlated with each other and, thus, the inferences drawn on the basis of univariate statistical analysis may be misleading due to the violation of the assumption of independence. On the other hand, simultaneous changes in lung function in man in different age groups cannot be tested using univariate statistical techniques. Keeping in view such shortcomings of the univariate statistical techniques, an attempt has been made in the present investigation to study simultaneous changes in some lung function tests [viz. vital capacity (VC), forced vital capacity (FVC), forced expiratory volume for one second (FEV1), expiratory reserve volume (ERV), inspiratory capacity (IC) and maximum voluntary ventilation (MVV)] at different age groups (viz. 21-25, 26-30, 31-35, 36-40, 41-45, 46-50, 51-55, 56-60 and 61-70 years) in healthy Indian males using multivariate statistical techniques (viz. Wilks' statistic (A) and Mahalanobis' D2 statistic) for drawing valid statistical inferences. It is concluded that remarkable significant changes take place in lung function after the age of forty years.

Adult↗

Assessment of reliability of lung function screening programs or longitudinal studies.

The aim was to determine reliability of lung function measurements performed according to recommendations of the American Thoracic Society (ATS) at a screening program in a large South African gold mine and to determine the usefulness of the reliability coefficient G for monitoring the reliability of lung function measurements in a mass screening program. The reliability coefficient G estimates the amount of random error of measurement, relative to the total variation in a measurement. The coefficient G was calculated as a correlation coefficient between two consecutive lung function tests performed within 6 mo, over a period of 43 mo on 3,378 miners. There was significant temporal variability in the reliability. For FEV(1), the coefficient G showed increased variability over the first 5 mo and stabilized at a value of 0.93 for the next 23 mo, after which it systematically declined over the next 15 mo. We estimated that in a large screening program, an optimal sample size of around 900 miners, examined randomly throughout the year, on a yearly basis, would provide a sufficient sample to examine monthly or quarterly fluctuation in the reliability. The value of the reliability coefficient G did not change when the time between two consecutive tests increased up to 15 mo. In conclusion, monitoring of lung function reliability in a screening program by the reliability coefficient G should improve data quality, and provide a measure on which the confidence in a decision-making process could be based when examining temporal changes in lung function for individual subjects.

Adult↗

Lung function reference values in Singaporean children aged 6-18 years.

BACKGROUND: A study was undertaken to produce reference values of lung function in Chinese children and a means of calculating adjusted standard deviation scores of lung function for Malay and Indian ethnic groups. METHODS: A cross sectional study of lung function (forced expiratory volume in one second and forced vital capacity) measured with a Jaeger spirometer was performed in a representative sample of Singaporean children made up of 1403 Chinese, 335 Malays, and 206 Indians. RESULTS: The relation between natural logarithms of lung function and height was approximately linear until 150 cm in boys and 140 cm in girls. At these heights there were abrupt changes in the gradients of both lines. Separate regression lines were derived for heights above and below these inflection points. Significant differences in lung function were seen in Chinese compared with Malay and Indian children. In particular, values were considerably lower among Indian boys. CONCLUSIONS: The relation between lung function and height in Chinese children is best described by two regression equations over separate height ranges. Information is provided for the calculation of reference values and standard deviation scores, together with the correction factors that need to be applied to derive these values in Malay and Indian children.

Adolescent↗

Impaired lung function in patients with IgA deficiency and low levels of IgG2 or IgG3.

We examined the relation between serum levels of IgG subclasses and lung function, as determined by spirometry, lung volumes, the single-breath nitrogen test, and static recoil pressures, in 29 patients with IgA deficiency and repeated upper or lower respiratory tract infections. Four of the patients had decreased levels of IgG2, and two had decreased levels of IgG3. Two or more lung-function values were abnormal in each of these six patients and also in three others with normal levels of IgG subclasses. Low levels of IgG2 and IgG3 were significantly related to abnormal lung function (P less than 0.01). The 20 patients with normal lung function all had IgG-subclass levels above the lower range. There may be a causal relation between low levels of IgG subclasses and deterioration in lung function, suggesting that patients with combined IgA and IgG-subclass deficiencies may benefit from immunoglobulin prophylaxis.

Adolescent↗

Lung function in Gypsies in Greece.

The relationship between lung function and smoking and dietary habits was examined in 121 Gypsies (62 males, 59 females) who were 14-70 y of age and who lived in Greece. All were examined clinically, after which they all participated in spirometry tests. Half of the study group had abnormal (< 80% of predicted) forced vital capacity, 36.4% had abnormal (< 80% of predicted) forced expiratory volume in 1 sec, and 5% had serious lung function disturbances (forced vital capacity < 50% of predicted). Approximately 70% of subjects were smokers, and their diets were rich in alcohol and meat; they ate very few salads and oranges. Consequently, decreased lung function might be a major health problem in Gypsies in Greece. Organization of preventive health strategies should improve the overall health of this study group.

Adolescent↗

Alterations in bronchoalveolar lavage fluid but not in lung function and bronchial responsiveness in swine confinement workers.

Testing of lung function and bronchial reactivity, bronchoalveolar lavage (BAL), and a skin prick test with a standard panel and six "swine" extracts obtained from swine and swine environment were performed in 20 randomly selected nonsmoking swine confinement workers. In addition, blood samples for detection of antibodies by the diffusion in gel-enzyme-linked immunosorbent assay (DIG-ELISA) technique and precipitating antibodies were drawn. Air samples for measurement of dust and endotoxin levels were collected. All the farmers regarded themselves as healthy. The results were compared with reference groups consisting of urban nonsmoking subjects who had not been exposed to pig farming environment. The pig farmers had normal lung function and the bronchial reactivity was not different from the reference group. In the BAL fluid of the farmers, the concentration of total cells and granulocytes was increased while the concentrations of lymphocytes and macrophages were normal. The BAL fluid concentrations of albumin, fibronectin, and hyaluronan were elevated in the farmers. Skin prick tests with swine extracts were negative in all farmers. Antibodies (assessed by DIG-ELISA) against swine dander, swine dust, and pig feed were increased and precipitating antibodies against swine dander were found in 14, against pig food in five, and against swine confinement dust in three of the 20 pig farmers. The concentration of airborne total dust was 7.4 mg/cu mm and the endotoxin concentration was 37 (22 to 60) ng/cu mm during tending the pigs and increased, during feeding, to 13.8 mg/cu mm and 315 (194 to 716) ng/cu mm, respectively. There was no correlation between exposure and lung function or lavage findings. In conclusion, randomly selected pig farmers had signs of airway inflammatory reaction and activation of the immune system without alteration in lung function and bronchial reactivity.

Adult↗

Regional and total lung function studies in patients with hemidiaphragmatic paralysis.

Global and regional lung function were studied in 17 subjects with hemidiaphragmatic paralysis. Global lung function (VC, MVV, and FEV1) in the sitting postion was reduced by an average of about 25%. Regional lung function data in the same position showed a considerable decrease in perfusion (19%), ventilation (20%), and lung volume (7%) of the diseased side as compared to reference values obtained in healthy volunteers. Compared to the partition of function in the supine, the perfusion of the affected lung increased when it was lowermost in the lateral decubitus postion, while regional FRC decreased and ventilation changed little. When uppermost, perfusion and ventilation of the affected lung decreased while FRCr increased somewhat. The arterial oxygen tension was significantly below normal in the supine position but in the normal range in the sitting position. It increased further during exercise. Bronchography showed compression of the basal lung segments on the affected side in the erect, and kinking and obliteration of lower lobe bronchi in the supine position and still more when the lung was lowermost in the lateral decubitus position.

Activities of Daily Living↗

Childhood asthma and lung function in mid-adult life.

The longitudinal lung function data in 286 subjects from a 28 year follow-up of childhood asthma is reported. Airway obstruction in mid-adult life was present mainly in those with moderately severe asthma. Subjects who had been wheeze free for at least 3 years, even if asthma had been persistent in childhood, had normal lung function and no increased bronchial reactivity. Only two subjects, both with persistent asthma from childhood, failed to show an improvement in FEV1 of greater than 10% following inhalation of a beta-adrenergic agonist. Subjects with relatively mild asthma who had not taken inhaled steroids did not appear to be disadvantaged with respect to lung function.

Adult↗

Evaluation of the suitability of weekly peak expiratory flow rate measurements in monitoring annual decline in lung function among patients with asthma and chronic bronchitis.

BACKGROUND: Early detection and treatment of patients with asthma or chronic bronchitis who have a rapid annual decline in lung function is essential in order to improve their long-term prognosis. This annual rate of decline can be assessed accurately by monitoring the forced expiratory volume in one second (FEV1) which is a routine procedure in hospital respiratory laboratories but not in general practice. General practitioners usually measure patients' peak expiratory flow rate (peak flow) to evaluate lung function. If annual decline in lung function can be assessed by monitoring peak flow, this method could be used in general practice for detecting patients at an early stage who have a rapid decline. AIM: A study aimed to investigate the long-term correlation between FEV1 and peak flow among a group of patients in Nijmegen, the Netherlands. METHOD: FEV1 and peak flow were monitored in 53 patients with moderate asthma and 78 patients with moderate chronic bronchitis over four years. FEV1 was measured in a laboratory once every six months and peak flow was measured by patients once a week. The correlation between the two sets of measurements was studied for each patient. RESULTS: Four-year data for 83 of the 131 patients were analysed; the other 48 patients received inhaled steroids during the second half of the study period so their data were not considered for all the analyses. Of the 83 patients, 35 (42%) showed a decrease in both FEV1 and peak flow. Thirty six patients (43%) showed a decrease in FEV1 and an increase in peak flow. Four patients (5%) showed an increase in FEV1 and a decrease in peak flow and eight patients (10%) showed an increase in both rates. Approximately similar results were seen in a separate analysis of all 131 patients during the first two years of the study. CONCLUSION: No long-term correlation was found between FEV1 and peak flow. Peak flow is not capable of detecting annual decline in lung function. Therefore it cannot be used to detect patients with asthma or chronic bronchitis who have a rapid annual decline in lung function. Spirometers, which measure peak flow and FEV1, could be used in general practice. These would allow general practitioners to continue measuring peak flow in order to assess short-term changes in lung function while providing an important means for monitoring FEV1 to assess long-term changes in lung function.

Adult↗

[Lung function reference values for students 6 to 16 years of age].

The diagnosis of lung function impairments in childhood is based on a variety of reference values. The assessment of "normal" function and growth of lung and airways in pediatric and environmental investigations is biased. The detection of small airway disease at an early stage is based on flow volume measurements, however, reference values in Europe relied on small and highly selected groups of children. We examined 18,106 children and adolescents aged 6 to 16 years at their schools by standardized methods. After exclusion of children with poor cooperation, respiratory signs or symptoms and active smokers, regression analysis was applied for FVC, FEV1, PEF, MEF75, MEF50, MEF25, and MMEF predicted from standing height, sex, age and weight. Means and standard deviations (SD) of lung function parameters of healthy Austrian school children are presented as a basis for reference. Individual lung function can thus be evaluated in SD-scores. Flow measures representing small airway functions were found higher in adolescent girls. MEF25 showed the highest variability unexplained by anthropometric characteristics. The new reference values improve available tools for early detection of respiratory diseases and dysfunctions in children and adolescents and they should help to evaluate environmental and other factors influencing function and growth of lung and airways.

Adolescent↗

Passive smoking and lung function in alpha(1)-antitrypsin heterozygote schoolchildren.

BACKGROUND: A study was performed to determine whether Pi heterozygotes exposed to smoking have a higher risk of reduced lung function than Pi M homozygotes. METHODS: The effect of passive smoking on lung function was investigated in a cross sectional study of 997 primary and secondary schoolchildren aged 11-13 years categorised by Pi phenotype as either PiM homozygotes or Pi heterozygotes. Data on respiratory health and risk factors were collected by questionnaire, lung function was measured by spirometric tests, bronchial hyperresponsiveness was evaluated by methacholine test, atopic status was evaluated by skin prick testing, and a blood sample was collected to determine Pi phenotype. Urinary cotinine and creatinine concentrations were determined and assessment of exposure was made from questionnaire data and urinary cotinine concentrations. The results were analysed by multiple regression analysis. RESULTS: Sixty one subjects (6.1%) were found to be Pi heterozygotes. Lung function did not differ between homozygotes and heterozygotes. There was a reduction in lung function in subjects exposed to parental smoking in the overall sample: FEV(1)/FVC ratio (-0.78%), FEF(25-75) (-0.11 litres), and FEF(75) (-0.13 litres). Interaction terms between parental smoking and Pi status were significant with regard to FEV(1)/FVC ratio (p=0.035) and FEF(50) (p=0.023). In subjects exposed to parental smoking the decrement in lung function in Pi heterozygotes tended to be greater (FEV(1)/FVC ratio = -2.57, FEF(25-75) = -0.30, FEF(50) = -0.43, and FEF(75) = -0.29) than in PiM homozygotes. These results did not change significantly when the urinary cotinine concentration was used as an exposure variable. CONCLUSIONS: The detrimental effect of environmental tobacco smoke on lung function in schoolchildren is confirmed. This harmful effect is greater in Pi heterozygotes than in PiM homozygotes.

Adolescent↗

Lung function in workers using cadmium containing solders.

The lung function of 57 male workers previously exposed to cadmium in connection with the use of cadmium containing solders was examined by spirometry (FVC, FEV1, FEV%, and MMF) and single breath nitrogen washout (CV, CV%, and phase III). A reference group (n = 31) from a nearby industry was examined at the same time. Despite the fact that the exposure in previous years had been relatively high, in the order of 0.05-0.5 mg Cd/m3, and that 24 (42%) of the workers had cadmium induced renal damage in the form of beta 2-microglobulinuria there was no evidence of pulmonary damage. There were no significant differences in lung function data from the exposed and reference group and there was no dose-response relation within the exposed group. It thus appears that signs of kidney toxicity in the form of low molecular weight proteinuria precede those that may be identified in the lung with commonly used lung function tests.

Cadmium↗

Lung function and bronchial reactivity in aluminum potroom workers.

Lung function and bronchial reactivity were measured in 38 aluminum potroom workers with no airway symptoms and in 20 healthy referents (office workers). All of the participants were non-smokers. The magnitude of exposure to airborne dust (alumina) and fluorides was determined. The aluminum potroom workers had obstructive lung function impairment with a significant decrease in expiratory flow and an increase in residual volume. Diffusing capacity was found to be lower than in the referents. No bronchial hyperreactivity was found in the aluminum potroom workers. The exposure to inhaled alumina and particulate and gaseous fluorides in the plant was low, 15-20% of the Swedish exposure limits. The finding of only modest lung function alterations with no bronchial hyperreactivity in the aluminum potroom workers is not consistent with the results of other authors. This discrepancy can probably be explained by the fact that the exposure to inhaled contaminants in the investigated aluminum plant was low.

Adult↗