Spirometric Measures Of Lung Function Research Articles

Risk factors for adult‐onset asthma: A 14‐year longitudinal study

Few longitudinal studies have examined the risk factors and natural history of adult-onset asthma. This study assessed the subject characteristics and lifestyle factors that predicted the new diagnosis of asthma in adulthood and how these factors changed over time in those who developed asthma compared with those who do not. The study enrolled 1554 adults from the Busselton Health Study seen in 1981 and again in 1994-1995 who initially reported never having had doctor-diagnosed asthma. Questionnaire measures were used to assess doctor-diagnosed asthma, respiratory history and tobacco smoking. Height, weight and spirometric measures of lung function were measured. Atopy was assessed by skin prick tests. Logistic regression analysis was used to identify risk factors for adult-onset asthma and changes over time. Reported wheeze, rhinitis, chronic cough, smoking and lower levels of lung function in 1981 each predicted asthma diagnosis by 1994-1995. Neither initial skin-prick reactivity nor newly positive skin-prick tests at follow up were associated with adult-onset asthma. Those diagnosed with asthma were more likely to have new wheeze, new rhinitis, new habitual snoring, weight gain and excess decline in lung function. Adult-onset asthma has risk factors that are distinct from those observed in childhood asthma. The presence of upper airway symptoms including rhinitis, as well as lifestyle factors, such as smoking, predicts those at greatest risk. However, neither pre-existing atopy nor new atopy as measured by skin prick tests was associated with adult-onset asthma.

Airway wall attenuation: a biomarker of airway disease in subjects with COPD

The computed tomographic (CT) densities of imaged structures are a function of the CT scanning protocol, the structure size, and the structure density. For objects that are of a dimension similar to the scanner point spread function, CT will underestimate true structure density. Prior investigation suggests that this process, termed contrast reduction, could be used to estimate the strength of thin structures, such as cortical bone. In this investigation, we endeavored to exploit this process to provide a CT-based measure of airway disease that can assess changes in airway wall thickening and density that may be associated with the mural remodeling process in subjects with chronic obstructive pulmonary disease (COPD). An initial computer-based study using a range of simulated airway wall sizes and densities suggested that CT measures of airway wall attenuation could detect changes in both wall thickness and structure density. A second phantom-based study was performed using a series of polycarbonate tubes of known density. The results of this again demonstrated the process of contrast reduction and further validated the computer-based simulation. Finally, measures of airway wall attenuation, wall thickness, and wall area (WA) divided by total cross-sectional area, WA percent (WA%), were performed in a cohort of 224 subjects with COPD and correlated with spirometric measures of lung function. The results of this analysis demonstrated that wall attenuation is comparable to WA% in predicting lung function on univariate correlation and remain as a statistically significant correlate to the percent forced expiratory volume in 1 s predicted when adjusted for measures of both emphysema and WA%. These latter findings suggest that the quantitative assessment of airway wall attenuation may offer complementary information to WA% in characterizing airway disease in subjects with COPD.

Paternal Asthma, Mold Exposure, and Increased Airway Responsiveness Among Children With Asthma in Costa Rica

Little is known about the determinants of airway hyperresponsiveness (AHR) among children with asthma in Hispanic America. We examined the relations among selected familial and environmental factors, markers of allergy, spirometric measures of lung function, and AHR in a cross-sectional study of 403 Costa Rican children with asthma between the ages of 6 and 14 years. Study participants completed a protocol that included questionnaires, spirometry, measurements of serum total and allergen-specific IgE, peripheral blood eosinophil count, and body mass index, and the assessment of airway responsiveness to methacholine (ie, a methacholine challenge test [MCT]). AHR to MCT was defined as the provocative dose of methacholine causing a 20% fall in FEV(1). Linear regression was used for the univariate and multivariate analyses. Of the 403 asthmatic children who underwent an MCT, 350 (86.8%) had AHR to methacholine. In a multivariate analysis, paternal asthma (p = 0.004), parental report of mold/mildew in the child's home (p = 0.04), FEV(1)/FVC ratio (p < 0.0001), and a positive IgE response to Der p 1 (p = 0.008) were significantly associated with AHR among Costa Rican children with asthma. Our results suggest that paternal asthma and environmental exposure to mold/mildew are strong determinants of AHR in Costa Rican children with asthma. FEV(1)/FVC ratio may be a useful measure of AHR (a marker of asthma severity) among Costa Ricans and other Hispanic Americans for whom reference values for FEV(1) are not currently available.

The Effect of Lung Volume Reduction Surgery on Chronic Obstructive Pulmonary Disease Exacerbations

Lung volume reduction surgery (LVRS) has been demonstrated to provide a functional and mortality benefit to a select group of subjects with chronic obstructive pulmonary disease (COPD). The effect of LVRS on COPD exacerbations has not been as extensively studied, and whether improvement in postoperative lung function alters the risk of disease exacerbations is not known. To examine the effect, and mechanism of potential benefit, of LVRS on COPD exacerbations by comparing the medical and surgical cohorts of the National Emphysema Treatment Trial (NETT). A COPD exacerbation was defined using Centers for Medicare and Medicaid Services data and International Classification of Diseases, Ninth Revision, discharge diagnosis. There was no difference in exacerbation rate or time to first exacerbation between the medical and surgical cohorts during the year before study randomization (P = 0.58 and 0.85, respectively). Postrandomization, the surgical cohort experienced an approximate 30% reduction in exacerbation frequency (P = 0.0005). This effect was greatest in those subjects with the largest postoperative improvement in FEV(1) (P = 0.04) when controlling for changes in other spirometric measures of lung function, lung capacities, and room air arterial blood gas tensions. Finally, LVRS increased the time to first exacerbation in both those subjects with and those without a prior history of exacerbations (P = 0.0002 and P < 0.0001, respectively). LVRS reduces the frequency of COPD exacerbations and increases the time to first exacerbation. One explanation for this benefit may be the postoperative improvement in lung function.

Tests de marche : une avancée dans l'évaluation fonctionnelle cardiorespiratoire

Exercise testing provides information on physical capacity during exercise in addition to spirometric measures of lung function or assessment on treadmills or ergonomic cycle. The “gold standard” assessment of exercise tolerance is measured in the laboratory using treadmills or ergonomic cycle but the necessary equipment is expensive and may not be readily accessible; such tests require people used to work with children. Walking tests are field tests providing a valid and easily accessible method of measuring function-limited exercise tolerance in patients with respiratory or cardiac chronic diseases. These walking tests are non-threatening, inexpensive, easy to perform and to understand for children. Walking tests performed in daily practice are the following: “time-based” tests (2-, 6- or 12-min walking test), 3-min step test (on a step) and the shuttle walking test. It may be a useful measure to assess therapeutic intervention and provide information on the prognosis. They are simple and safe methods to evaluate quality of life in these patients.

Asthma in Hispanics

Hispanic individuals trace their ancestry to countries that were previously under Spanish rule, including Mexico, large parts of Central and South America, and some Caribbean islands. Most--but not all--Hispanics have variable proportions of European, Amerindian, and African ancestry. Hispanics are diverse with regard to many factors, including racial ancestry, country of origin, area of residence, socioeconomic status, education, and access to health care. Recent findings suggest that there is marked variation in the prevalence, morbidity, and mortality of asthma in Hispanics in the United States and in Hispanic America. The reasons for differences in asthma and asthma morbidity among and within Hispanic subgroups are poorly understood but are likely due to the interaction between yet-unidentified genetic variants and other factors, including environmental tobacco smoke exposure, obesity, allergen exposure, and availability of health care. Barriers to optimal management of asthma in Hispanics in the United States and in Hispanic America include inadequate access to health care, suboptimal use of antiinflammatory medications, and lack of reference values for spirometric measures of lung function in many subgroups (e.g., Puerto Ricans). Future studies of asthma in Hispanics should include large samples of subgroups that are well characterized with regard to self-reported ethnicity, country of origin, place of birth, area of residence, and indicators of socioeconomic status. Because Hispanics are disproportionately represented among the poor in the United States, implementation of adequate access to health care and social reforms (e.g., improving housing conditions) would likely have a major impact on reducing asthma morbidity in this population.

Racial Differences in T-Lymphocyte Response to Glucocorticoids

Asthma morbidity and mortality is increased in blacks. The primary objective of this cross-sectional study was to determine if blacks, asthmatic or nonasthmatic, displayed diminished T-lymphocyte response to glucocorticoids in vitro compared to their white counterparts. If differences were noted, this would suggest a racial predisposition to decreased glucocorticoid responsiveness among blacks. Asthmatic (n = 395, 27% blacks) and control (n = 202, 52% blacks) subjects recruited from National Jewish Medical and Research Center and from the surrounding community participated in the study. In vitro glucocorticoid responsiveness was determined by assessing the log-transformed concentration of dexamethasone required to suppress phytohemagglutinin-induced T-lymphocyte proliferation by 50% (log(10) IC(50)). Asthma medication history, atopic status, and spirometric lung function measures corrected for race were collected. Black and white asthmatic subjects had similar FEV(1) percentage of predicted values and inhaled and oral glucocorticoid requirements. Black asthmatic subjects displayed significantly diminished glucocorticoid responsiveness compared to white asthmatic subjects, as follows: median (first, third quartile) log(10) IC(50) values of 1.00 nmol (0.48, 1.83) vs 0.78 nmol (0.29, 1.45) [p = 0.028]. Similar results were found between black and white control subjects, as follows: median, 1.26 nmol (0.70, 2.14) vs 0.95 nmol (0.55, 1.48) [p = 0.01]. Age, race, and basal T-lymphocyte activity were significantly positively correlated to the log(10) IC(50) values. Our observation that black asthmatic subjects and non-asthmatic control subjects require greater concentrations of glucocorticoid in vitro to suppress T-lymphocyte activation suggests that blacks have a racial predisposition to diminished glucocorticoid responsiveness, which may contribute to their heightened asthma morbidity.

Racial differences in T lymphocyte response to glucocorticoids

Rationale The primary objective of this study was to determine if blacks, asthmatic or non-asthmatic, displayed diminished T lymphocyte response to glucocorticoid (GC) in vitro compared to their white counterparts. If differences were noted, this would suggest a racial predisposition to decreased GC responsiveness among blacks. Methods Asthmatic (n=395, 27% blacks) and control (n=202, 52% blacks) subjects recruited from National Jewish and from the surrounding community participated in the study. In vitro GC responsiveness of peripheral blood T lymphocytes was determined using log 10 IC 50 values (i.e. dexamethasone concentration required to suppress phytohemagglutinin-stimulated T lymphocytes by 50%). Asthma medication history, atopic status, and spirometric lung function measures corrected for race were collected. Results Black and white asthmatics had similar FEV 1 % predicted and inhaled and oral GC requirements. Black asthmatics displayed significantly diminished GC responsiveness compared to whites (log 10 IC 50 values of 1.20 ± 1.06 vs. 0.92 ± 1.05, P<0.02). Qualitatively similar results were found between black and white controls (1.59 ± 1.18 vs 1.18 ± 1.04, P<0.01). Age, ethnicity, and basal T lymphocyte activity were significantly correlated to the log 10 IC 50 values. Conclusion Our observation that black asthmatics and non-asthmatic controls require greater concentrations of GC in vitro to suppress T lymphocyte activation suggests blacks to have a racial predisposition to diminished GC responsiveness which may contribute to their heightened asthma morbidity.

Basic pulmonary function tests in pig farmers

Many epidemiological and clinical studies have demonstrated an increased risk for the symptoms of respiratory disorders consistent with chronic bronchitis and asthma and alterations of pulmonary function tests in pig farmers. The aim of this study was to determine basic pulmonary function values in workers in swine confinement buildings and to compare them with the same values in the control group of unexposed persons. The next aim was to examine the association between these values with duration of professional exposure, cigarette smoking, age, and sex of the examined persons. We randomly selected for examination 145 workers of both sex who had worked for at least 2 previous years in pig farms and spent at least 3 hours per day, 6 days per week in a swine confinement building. The farmers worked at 6 different farms with 12,383 pigs on average on each farms. The subject was eligible for the study if he had had no history of atopic disease nor any serious chronic disease, and no acute respiratory infection within 3 previous months. As control group we examined 156 subjects who had lived and/or worked in the same areas and had had no history of exposure to farming environment or any other known occupational air pollutants. In both groups the study comprised cigarette smokers and persons who had never smoked. Pulmonary function data were collected according to the standard protocol with a Micro Spirometer, (Micro Medical Ltd, England, UK). The registered parameters were FEV1 and FVC. At least three satisfactory forced maximal expirations were performed by each subject and the best value was accepted for analyses. The results were also expressed as a percentage of predicted values and FEV1/FVC x 100 was calculated. There were no differences in the main demographic characteristics between two examined groups (Table 1). Mean duration of work in pig farming was 11.6 years (SD=8.5; range 2-40). The average values of examined pulmonary function tests are shown in table 2. The values of FEV1 and FVC in each groups were between 92% and 97% of predicted values, and FEV1/FVC x 100 was not lower than 82%. There were no differences in the average values of FEV1 (p=0.574) and FEV1 % predicted (p=0.653) between pig farmers and control subjects. Pearson coefficient of correlation and Spearman nonparametric correlation test revealed a high level of correlation of FEV1 values with sex and age and no correlation of pig farming exposure with cigarette smoking as predictor variables (Table 3). The analysis by linear regression method showed that all examined predictor variables had the effect on the value of FEV1 (Table 4). After the elimination of the two least significant predictor variables it was possible to make the equation for prediction of FEV1 values. In the present study there are no significant alterations in the values of the basic pulmonary function tests in pig farmers. In the majority of previous similar studies the differences in the average values of FEV1 and FVC between pig farmers and control subjects were also not found. However, in some studies the alterations in several more specific lung function parameters were registered. The decreased values of FEV1 during workshift were also found and they are probably connected to the bronchial hyperreactivity registered in many studies in pig farmers. Longer exposure to swine confinement environment caused more decline in FEV1 and FVC and accelerated mean age-related annual decline in FEV1 was observed reaching to 44 ml/yrs more than expected. The correlations between values of FEV1 with pig farming exposure and cigarette smoking in this study were not found. However, the analysis by linear regression method showed that all examined predictor variables had the effect on the value of FEV1. In a few previous bronchoscopic, BAL and sputum studies some signs of inflammation and morphological changes of the respiratory tract were observed. The absence of important alterations in the basic spirometric measures in this and the majority of the previous studies suggests that early airway injuries may not be readily apparent using spirometric measures of lung function. In contrast to other world studies, our study comprised an important number of women farmers, but alterations associated to sex were not found. To assess the lung function in these pig farmers after several years may be of great importance.

Photodynamic Therapy

Photodynamic Therapy

Pulmonary function, inflammation, exercise capacity and quality of life in cystic fibrosis.

The aim of the study was to determine the extent to which treatment induced changes in exercise capacity and quality of life (QoL) are related to spirometric measures of lung function and other measures of disease impairment. Twenty patients admitted to hospital with an exacerbation of pulmonary disease were recruited. Measures of disease impairment, disability and QoL were obtained at the beginning and end of an intravenous course of antibiotic therapy. Intravenous antibiotic treatment resulted in a significant improvement in all measures of disease impairment, disability and handicap. The only significant predictor of treatment induced change in exercise capacity was C-reactive protein (CRP) and this explained 28% of the variance in change in exercise capacity. In the case of QoL, two predictors (change in exercise capacity and sputum output) contributed significantly to the change in QoL and collectively explained 54% of the variance in QoL. Lung function provides a limited index of treatment outcome. Exercise capacity and quality of life assessment have the potential to make a significant contribution to the decision making process regarding treatment choices in cystic fibrosis and should be measured directly if a comprehensive evaluation of the effect of treatment is required.

Reliability, Repeatability, and Sensitivity of the Modified Shuttle Test in Adult Cystic Fibrosis

The purpose of this study was to investigate the test-retest reliability, repeatability, and sensitivity of the modified shuttle test (MST) in adult patients with cystic fibrosis (CF). : Prospective study. Adult CF Unit, Belfast City Hospital. : Adult patients with CF. Test-retest reliability-none; sensitivity-inpatient IV antibiotic therapy for an acute exacerbation of respiratory disease. The test-retest reliability and repeatability of the MST was assessed by comparing performance on two consecutive MSTs performed in 12 patients with CF and stable disease. The sensitivity of the MST was assessed by measuring the change in MST performance after 2 weeks of IV antibiotic therapy in 24 patients admitted to hospital with acute exacerbations of their respiratory disease. In the assessment of test-retest reliability and repeatability (n = 12), there was a significant and strong correlation between trials for distance completed (Pearson's r = 0. 99; p < 0.01), peak heart rate (Pearson's r = 0.99; p < 0.01), peak arterial oxygen saturation (SaO(2); Pearson's r = 0.99; p < 0.01), and peak Borg rating of perceived breathlessness (Pearson's r = 0. 99; p < 0.01). The coefficients of repeatability for these variables were small (coefficient of repeatability: distance completed, 4 shuttles; peak heart rate, 6 beats/min; peak SaO(2), 4%; and peak Borg rating of perceived breathlessness, 0.9). In the assessment of sensitivity (n = 24), the standardized response mean (SRM) for distance completed on MST (SRM = 1.18) was the SRMs for spirometric measures of lung function (FEV(1), SRM = 0.96; FEV(1) percent predicted, SRM = 0.88). This study demonstrates that the MST is a reliable, repeatable, and sensitive measure of exercise capacity in adult CF. The MST may be of value in determining prognosis, evaluation for lung transplantation, exercise prescription, and establishing the impact of new treatments on the disability associated with CF.

Testing patients' lungs: spirometry as part of the physical examination

Spirometric measurements of lung function are vital signs that unfortunately are not as widely used as blood pressure or cholesterol testing. Spirometry is an uncomplicated procedure that can easily be incorporated by primary care physicians into routine physical examinations, especially now that simple handheld spirometers suitable for all offices are available. Abnormal spirometric patterns can alert physicians to patients' additional risk of developing chronic lung disease and to the need for interventions that prevent or forestall morbidity and mortality. Spirometry also is an important tool for monitoring patients' response to therapy in a number of disorders (eg, asthma). Spirometric testing in adults should begin at age 40 for smokers and patients with unexplained dyspnea, cough, wheezing, or excessive mucus. Children with asthma and cystic fibrosis should be identified and followed with Spirometry.

The adaptations of a quality of life questionnaire for routine use in clinical practice: the Chronic Respiratory Disease Questionnaire in cystic fibrosis.

The assessment of quality of life (QoL) is necessary to monitor the course of disease and to assess the effect of new and existing interventions in clinical practice. This will only be achieved if QoL can be measured accurately and routinely. The aim of this study was to demonstrate the methodology involved in the adaptation and shortening of the Chronic Respiratory Disease Questionnaire (CRDQ) in a population of adults with cystic fibrosis (CF). A single interviewer administered the CRDQ to a sample of 45 adult patients (32 males) with CF prior to assessment of spirometric measures of lung function. Those patients whose lung function was stable at the time of study and who could attend for a retest within 14 days were asked to complete the questionnaire at a subsequent visit (n = 10). The mean interval between visits was 7 days (range 5-14 days). Correlations between spirometry and CRDQ dimensions ranged from -0.003 to 0.426. The fatigue, emotion and mastery dimensions showed high internal consistency and adequate construct validity. In the small number of patients suitable for retest, the results indicated that the dimensions exhibited adequate test-retest reliability. In contrast, low internal consistency was demonstrated for the dyspnoea dimension. The fatigue, emotion and mastery dimensions could be reduced, in terms of their number of items, without a substantial loss in explanatory power. This study suggests that QoL measurement can be made convenient and, thus, more easily accessible for routine clinical assessment.

Longitudinal study of respiratory health in dairy farmers: influence of artificial barn fodder drying.

Factors influencing respiratory consequences of dairy farming have not been extensively investigated to date. To evaluate the effects of barn fodder drying on respiratory symptoms and lung function, a 5 yr follow-up study was performed in the Doubs (France). A cohort of male dairy farmers was analysed in 1990. The initial cross-sectional results suggested that barn-drying fodder may protect dairy farmers from lung function impairment. In 1995, 113 barn-drying farmers (92%) and 231 traditional-drying farmers (84%) were re-analysed. Barn and traditional fodder-drying farmers were compared for prevalence of symptoms and spirometric measures of lung function. After controlling for age, smoking status, altitude and cumulative exposure, barn-drying farmers compared to traditional-drying farmers had a lower prevalence of chronic bronchitis (4 versus 10%; p<0.05) and slightly higher values of forced expiratory volume in one second (FEV1) (p=0.06) and FEV1/vital capacity (VC) (p<0.01). Nevertheless, decline of the respiratory function parameters was not significantly different between the two groups. Variables positively and significantly associated to longitudinal decline of lung function parameters were: age (FEV1, FEV1/VC); altitude (VC, FEV1) and chronic bronchitis and dyspnoea at the initial survey (FEV1/VC). Persistence and emergence of chronic bronchitis, dyspnoea and symptoms at exposure were also significantly associated to an acceleration in the annual decline of the respiratory function. In conclusion, the mode of fodder drying does not seem to significantly influence the decline in lung function. Nevertheless, this study confirms the results of the initial cross-sectional analysis and supports the hypothesis that barn drying fodder may have a protective effect on respiratory health in dairy farming.

Effect of an NK1 receptor antagonist (CP-99,994) on hypertonic saline-induced bronchoconstriction and cough in male asthmatic subjects.

To investigate the role of NK1 receptors in the pathogenesis of bronchoconstriction and cough in asthma, we performed a randomized, double-blind, crossover study on the effects of a selective non-peptide tachykinin NK1 receptor antagonist (CP-99,994) on baseline measures of lung function and on hypertonic saline-induced bronchoconstriction and cough in 14 male subjects with mild asthma. CP-99,994 (250 micrograms/2 hours) and placebo were administered intravenously in 2-h infusions during consecutive visits 5 to 7 d apart. Specific airway resistance (SRaw) was measured and spirometry was performed at baseline and at 35 and 60 min. Next, hypertonic saline challenge was performed by delivering 10 breaths of saline of increasing concentration (0.9 to 7% in 1% increments at 5-min intervals) via an ultrasonic nebulizer until SRaw increased from baseline by 200% or 20 units, whichever was greater. Throughout the challenge cough was counted from a taped record made from two microphones placed close to the subject's larynx. We found that CP-99,994 did not significantly affect SRaw or spirometric measures of lung function during the first hour of infusion. Although CP-99,994 infusion markedly attenuated the bronchoconstrictor response to the saline challenge in two subjects, it did not significantly decrease the area under curves obtained for SRaw and cough during saline challenge for the group as a whole (p = 0.9 for SRaw;p = 0.8 for cough). We conclude that administration of 250 micrograms/kg of CP-99,994 over 2 h does not significantly inhibit hypertonic saline-induced bronchoconstriction or cough in subjects with mild asthma and does not have acute bronchodilator activity in these subjects.

Determinants of longitudinal changes in spirometric function among swine confinement operators and farmers.

To assess whether working in a swine confinement facility causes an excess or accelerated decline in lung function, we conducted a population-based study to evaluate the determinants of longitudinal changes in airflow in a population of swine confinement operators. Spirometric measures of lung function were compared between swine confinement operators (N = 168) and neighborhood farmer control subjects (N = 127). Study subjects were randomly selected from a cohort of swine confinement operators in eastern Iowa. The control farming population was matched by geographic location, age, and sex to the swine confinement operators. On average, the follow-up time was approximately 2 yr, with a range of follow-up between 56 and 1,900 d. Although swine confinement operators and neighborhood farmers had similar demographic characteristics (age, gender, racial background, smoking history, and atopy status), swine confinement operators tended to have less farming experience and were more extensively followed (more measures of lung function and longer periods of observation) than the neighborhood farmer control group. Swine confinement operators were also exposed to higher environmental dust concentrations and other irritants than the farmer control subjects. Interestingly, the cross-sectional data indicated that swine confinement operators tended to have slightly lower measures of airflow and greater workshift declines in forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and mid-expiratory flow (FEF25-75) than the neighborhood farmer control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Dust- and endotoxin-related respiratory effects in the animal feed industry.

A cross-sectional study of 315 animal feed workers was undertaken in 14 animal feed mills in the Netherlands. Primary aims were to explore relationships between exposure to organic dust and respiratory symptoms and chronic lung function changes. The study comprised monitoring dust and endotoxin exposure, spirometric lung function measurements (FVC, FEV1, mean midexpiratory flow, and flow-volume parameters) and a questionnaire for respiratory symptoms. The exposure was measured in two periods, during spring and autumn. The average 8-h personal inspirable dust exposure was 9 mg/m3 grain dust (range, 0.2 to 150 mg/m3) and 25 ng/m3 endotoxin (range, 0.2 to 470 ng/m3) based on 530 personal dust measurements. On the basis of these measurements and the occupational history of the workers, the number of years "worked in dust" and an estimate of the cumulative dust and endotoxin exposure were calculated. The prevalence of most chronic respiratory symptoms tended to decrease with increasing years of exposure. The "healthy worker effect" is probably responsible for this finding. In general, a strong negative association between most of the exposure variables and lung function was found. The endotoxin exposure was more strongly related to decreases in lung function than the dust exposure. The estimated effects of an average (cumulative) endotoxin exposure on lung function were greater, with a higher statistical significance, than for an exposure to dust. These results suggest that endotoxin exposure is an important factor in the development of respiratory impairment. The lung function changes occur at endotoxin levels ranging from 0.2 to 470 ng/m3.

LONG-TERM EFFECTS OF SOLDERING FUMES UPON RESPIRATORY SYMPTOMS AND PULMONARY FUNCTION

To evaluate the long-term effect of soldering gases and fumes, and of cigarette smoke on lung function, and the prevalence of respiratory symptoms, a comparative study of spirometric measurements in 57 solderers engaged in acetylene gas soldering of brassware joints in the brass industry (mean exposure: 12.4 +/- 1.1 years) and in 131 controls was performed. The two groups were similar in age, height, smoking habits and social class. The prevalence of respiratory symptoms in the solderers did not differ significantly from that in the unexposed controls (59.6 vs 56.4%). However, solderers who smoked showed higher prevalence of respiratory symptoms than those who did not smoke; a similar trend was observed in the controls. The study failed to demonstrate any association between the respiratory symptoms and length of exposure. The respiratory status of the solderers was unaffected as the results of spirometric measurements of lung function did not show any significant differences between the exposed and the control groups, indicating the absence of an additive effect of cigarette smoking and exposure to soldering fumes.

Lung function of welders of zinc-coated mild steel: cross-sectional analysis and changes over five consecutive work shifts.

Spirometric lung-function measurements were conducted 5 days before and after the work shift of 11 welders of zinc-coated steel, ten nonwelders who were indirectly exposed to welding fumes, and 17 controls. The exposure to dust and zinc of all participants was monitored personally using PAS-6 samplers. Geometric mean concentrations for welders were 0.91 mg/m3 (dust) and 34.0 micrograms/m3 (zinc). Cross-sectional analysis of Monday morning values showed no differences in lung-function parameters between groups. However, the number of years the participants were engaged in welding was of borderline statistical significance and correlated negatively with values of FEV1 and FEV1/FVC. Changes in lung function over a work shift or a working week were not related to the exposure level.