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Effects on symptoms and lung function in humans experimentally exposed to diesel exhaust.

OBJECTIVES: Diesel exhaust is a common air pollutant made up of several gases, hydrocarbons, and particles. An experimental study was carried out which was designed to evaluate if a particle trap on the tail pipe of an idling diesel engine would reduce effects on symptoms and lung function caused by the diesel exhaust, compared with exposure to unfiltered exhaust. METHODS: Twelve healthy non-smoking volunteers (aged 20-37) were investigated in an exposure chamber for one hour during light work on a bicycle ergometer at 75 W. Each subject underwent three separate double blind exposures in a randomised sequence: to air and to diesel exhaust with the particle trap at the tail pipe and to unfiltered diesel exhaust. Symptoms were recorded according to the Borg scale before, every 10 minutes during, and 30 minutes after the exposure. Lung function was measured with a computerised whole body plethysmograph. RESULTS: The ceramic wall flow particle trap reduced the number of particles by 46%, whereas other compounds were relatively constant. It was shown that the most prominent symptoms during exposure to diesel exhaust were irritation of the eyes and nose and an unpleasant smell increasing during exposure. Both airway resistance (R(aw)) and specific airway resistance (SR(aw)) increased significantly during the exposures to diesel exhaust. Despite the 46% reduction in particle numbers by the trap effects on symptoms and lung function were not significantly attenuated. CONCLUSION: Exposure to diesel exhaust caused symptoms and bronchoconstriction which were not significantly reduced by a particle trap.

Adult↗

Lung function in older humans: the contribution of body composition, physical activity and smoking.

An allometric model was used to determine the important factors related to the decline in forced expiratory volume (FEV1.0) across ages 55-86 years in independently living men and women. Measurements were available from a randomized sample of 181 men and 203 women residing in London, Ontario, Canada. The effects of height, age, sex, adiposity, fat free mass (FFM), grip strength and physical activity (PA) on FEV1.0 were assessed using an allometric model to test the hypothesis that sex differences in lung function would be due in part to sex-related differences in the aforementioned variables and would therefore be eliminated by our analysis. The following model was linearized and parameters were identified using standard multiple regression: FEV1.0 = height(beta1) x FFM(beta2) x grip strength(beta3) x PA(beta4) x exp(beta0 + beta5age + beta6sex + beta7smoking + beta8%body fat) x epsilon. Results indicate that the amount of FFM and heavy intensity physical activity participated in by the elderly may be more important in influencing forced expiratory function than previously recognized. In addition, results from this study have confirmed the importance of age and height in the prediction of FEV1.0 and demonstrated a negative effect of smoking on lung function. Individuals with a greater FFM and physical activity level tended to be associated with an above average lung function performance. The cross-sectional rate of decline in FEV1.0 determined from our model was approximately 12% per decade.

Aged↗

Postnatal lung function after prenatal steroid treatment in sheep: effect of gender.

The effect of fetal gender on postnatal lung function and response to prenatal steroid exposure were examined retrospectively in a group of 115 preterm lambs. Fetuses received a single intramuscular injection of 0.5 mg/kg betamethasone alone or in conjunction with L-thyroxine 48 h before delivery at 128-d gestational age. Control animals received an equivalent volume of saline. After delivery, respiratory mechanics and blood gas parameters were recorded for 40 min. Deflation pressure volume curves were constructed in excised lungs. Right upper lobes from a randomly selected subgroup of control animals were examined morphometrically. Control (saline-treated) females were able to be ventilated at lower ventilatory pressures with equivalent tidal volumes and more efficient gas exchange. There were no gender differences in compliance, conductance, or excised lung volumes for saline-treated animals. More efficient gas exchange in females could not be explained by thinner alveolar septa or greater alveolar surface area. After hormone treatment, both males and females exhibited significant improvements in respiratory mechanics, gas exchange, and an increase in alveolar surfactant concentration. However, female exhibited a significantly greater improvement than males for compliance, conductance, excised lung volume, and arterial oxygen partial pressure. These data provide a comprehensive description of gender differences in postnatal lung function and response to steroid treatment in preterm animals, and support clinical findings of sexual dimorphism.

Animals↗

Academic examinations significantly impact immune responses, but not lung function, in healthy and well-managed asthmatic adolescents.

The influence of academic examinations on immunity and lung function was investigated in 64 adolescents to determine if stress-related changes would differ between healthy and asthmatic students. Blood samples were collected on three occasions: 1 month prior, during, and 2-3 weeks after exams. Leukocyte subsets were enumerated, and in vitro assays were conducted to assess lymphocyte proliferative and cytolytic responses and neutrophil production of superoxides. Examinations elicited significant changes in several lymphocyte subsets and marked alterations in the three functional measures in all students. However, the magnitude and pattern of change did not differ between healthy and asthmatic students. Similarly, neither mild nor more severe asthmatics showed an exam-related decrement in lung function, as reflected by peak expiratory flow rate. This research validated that examinations are a salient cause of altered immune responses, but indicates that there is not a concomitant aggravation of inflammatory disease in well-managed asthmatics.

Adolescent↗

Subtle immunodeficiency in severe asthma: IgA and IgG2 correlate with lung function and symptoms.

BACKGROUND: Atopy, increased serum IgE and eosinophilic airway inflammation are common in asthma and may indicate aberrant immune responses, but the cause(s) are unknown. It was hypothesized that differences in serum immunoglobulins, immunoglobulin free light chains (FLC) and secretory IgA (sIgA) would exist between subjects with asthma of varying severity and normal subjects, and the levels would correlate with lung function, symptoms and airway inflammation. METHODS: Serum IgG, IgA, IgE and IgM, IgG subclasses and FLC, and bronchoalveolar lavage sIgA were evaluated from 15 normal subjects, 9 mild and 22 severe asthmatics with similar atopic status. Asthma symptoms were obtained by questionnaire, and airway inflammation was assessed by immunostaining for five inflammatory cell types. RESULTS: Immunoglobulin levels in all groups were generally within the normal range. However, IgA and IgG were lower in severe asthmatics than normal subjects (overall p = 0.006 and 0.02, respectively). IgA, but not IgG, correlated with lung function and asthma symptoms (r-values >0.58; p-values <0.009). Although similar among the groups, higher sIgA and IgG(2) also positively correlated with lung function and negatively with asthma symptoms (r-values >0.63; p-values <0.009). IgA and IgG/IgG(1) positively correlated with tissue mast cells. CONCLUSIONS: Subtle alterations in IgA- and IgG(2)-mediated responses in asthma may be disease-related. As their levels are generally normal, it is possible that the quality/repertoire of immune protection provided by these isotypes, perhaps against carbohydrate epitopes, may be altered in asthma.

Adult↗

Lung function of Zimbabwean farm workers exposed to flue curing and stacking of tobacco leaves.

OBJECTIVES: To perform lung function tests on tobacco farm workers (TFWs) chronically exposed to flue curing and stacking of tobacco leaves and to compare them with vegetable farm workers (VFWs) who were not exposed to any known air pollutant (control). DESIGN: Comparative study. SETTING: Tobacco and vegetable farms. SUBJECTS: 20 TFWs and 30 VFWs. All subjects were male and the mean age, height and weight of the two groups were not significantly different. OUTCOME MEASURES: Lung function indices. RESULTS: Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and peak expiratory flow rate (PEFR) of the TFWs were 3.28 +/- 0.51 litres, 2.68 +/- 0.74 litres and 6.41 +/- 2.08 litres/second, respectively. These figures were significantly lower than 3.97 +/- 0.83 litres, 3.09 +/- 0.71 litres and 8.62 +/- 2.74 litres/second, respectively, for the control subjects (P < 0.01, 0.05 and 0.01, respectively). However, mean FEV1 as a percentage of the FVC (FEV1%) of the TFWs was not significantly different from that of the controls FVC of the TFWs declined with duration of service (r = 0.74; P < 0.01). CONCLUSION: The results are indicative of restrictive lung defect in the TFWs and may be attributed to long-term exposure to flue curing and stacking of tobacco leaves. The results also suggest the importance of the duration of exposure in the aetiology of lung impairment in this environment.

Adult↗

Does splenectomy in cystic fibrosis related liver disease improve lung function and nutritional status? A case series.

AIMS: To review the effect of total splenectomy on lung function and nutrition in children with cystic fibrosis related liver disease (CFLD) and associated portal hypertension. The stated indications for surgery and the short and long term risks of the procedure were also documented. METHOD: Over a 25 year period from January 1980 to June 2005, approximately 650 patients with cystic fibrosis (CF) were treated at the Royal Children's Hospital, Melbourne, Australia. Nine patients with CFLD who underwent a splenectomy during that time were identified and their medical records were reviewed. RESULTS: FEV1% predicted dropped by -16+/-11% in the two years pre-splenectomy. This contrasts with the increase in FEV1% predicted of 2+/-16% in the two years post-splenectomy (p = 0.05). The cumulative gain in WAZ score (DeltaWAZ pre) over the two years prior to splenectomy of 0.045+/-0.69 was not significantly different from the cumulative gain in WAZ score (DeltaWAZ post) for the two years after splenectomy of 0.15+/-0.36 (p = 0.65). The average age at splenectomy was 14.8 years (SD = 3 years). The average weight of an excised spleen was 983 g (SD = 414 g). There were no deaths associated with splenectomy. The median length of follow up post-splenectomy was 6.0 years (range 0.7-15.8). There were no episodes of bacterial peritonitis or overwhelming sepsis. CONCLUSIONS: Splenectomy may have a beneficial effect on lung function although this may not manifest itself until the second year post-splenectomy. Splenectomy in patients with CFLD appears to be a safe procedure.

Adolescent↗

Cross-sectional study of uranium mine workers to develop predictive equations for lung functions with reference to chronic obstructive pulmonary disease.

As the first part of a prospective epidemiological study of the lung function and dust exposure of workers at the Rössing Uranium Mine in SWA/Namibia, various measurements of lung function of 1,407 workers were carried out. This was necessary in order to follow up any chronic obstructive pulmonary disease that might develop. The opportunity was used to test existing prediction formulae and to develop formulae for normal values for workers at the Rössing mine.

Adult↗

Respiratory symptoms, lung function, and sensitisation to flour in a British bakery.

A survey of dust exposure, respiratory symptoms, lung function, and response to skin prick tests was conducted in a modern British bakery. Of the 318 bakery employees, 279 (88%) took part. Jobs were ranked from 0 to 10 by perceived dustiness and this ranking correlated well with total dust concentration measured in 79 personal dust samples. Nine samples had concentrations greater than 10 mg/m3, the exposure limit for nuisance dust. All participants completed a self administered questionnaire on symptoms and their relation to work. FEV1 and FVC were measured by a dry wedge spirometer and bronchial reactivity to methacholine was estimated. Skin prick tests were performed with three common allergens and with 11 allergens likely to be found in bakery dust, including mites and moulds. Of the participants in the main exposure group, 35% reported chest symptoms which in 13% were work related. The corresponding figures for nasal symptoms were 38% and 19%. Symptoms, lung function, bronchial reactivity, and response to skin prick tests were related to current or past exposure to dust using logistic or linear regression analysis as appropriate. Exposure rank was significantly associated with most of the response variables studied. The study shows that respiratory symptoms and sensitisation are common, even in a modern bakery.

Adult↗

Distinct patterns of respiratory difficulty in young children with achondroplasia: a clinical, sleep, and lung function study.

AIM: Achondroplasia can result in respiratory difficulty in early infancy. The aim of this study was to document lung growth during infancy, together with the cause of any cardiorespiratory and sleep dysfunction. PATIENTS AND METHODS: Seventeen prospectively ascertained infants (14 boys and three girls) with respiratory symptoms starting before 1 year of age underwent clinical, sleep, and lung function studies. RESULTS: Three distinct groups were identified. Group 1 (n = 6) were the least symptomatic and only had obstructive sleep apnoea. Group 2 (n = 6) had obstructive sleep apnoea of muscular aetiology and, neurologically, hydrocephalus and a small foramen magnum were common. Group 3 (n = 5), the most severely affected group, all developed cor pulmonale, with three deaths occurring as a result of terminal cardiorespiratory failure. All five had obstructive sleep apnoea with a muscular aetiology (a small foramen magnum predominated) with severe or moderately severe gastro-oesophageal reflux. Initially, lung function studies found no evidence of restriction or reduced lung volumes standardised according to weight. However, with growth these infants had worsening function, with raised airway resistance and severe reductions in respiratory compliance. CONCLUSIONS: These groups appear to be distinct phenotypes with distinct anatomical aetiologies: "relative" adenotonsillar hypertrophy, resulting from a degree of midfacial hypoplasia (group 1); muscular upper airway obstruction along with progressive hydrocephalus, resulting from jugular foramen stenosis (group 2); and muscular upper airway obstruction, but without hydrocephalus, resulting from hypoglossal canal stenosis with or without foramen magnum compression and no jugular foramen stenosis (group 3). The aetiology of these abnormalities is consistent with localised alteration of chondrocranial development: rostral, intermediary and caudal in groups 1, 2, and 3, respectively.

Achondroplasia↗

[Problems of lung function testing in the laboratory].

Spirometry is indispensable for the screening test of general respiratory function, and measurements of lung volume and diffusing capacity play an important role in the assessment of disease severity, functional disability, disease activity and response to treatment. Pulmonary function testing requires cooperation between the subjects and the examiner, and the results obtained depend on technical as well as personal factors. In order to diminish the variability of results and improve measurement accuracy, the Japan Respiratory Society published the first guidelines on the standardization of spirometry and diffusing capacity for both technical and clinical staff in 2004. It is therefore essential to distribute the guidelines to both laboratory personnel and general physicians. Furthermore, training workshops are mandatory to improve their understanding of the basics of lung function testing. Recently, there has been increasing interest in noninvasive methods of lung function testing without requiring the patient's cooperation during spontaneous breathing. Three alternative techniques, i.e. the negative expiratory pressure (NEP) method to detect expiratory flow limitation, impulse oscillation system (IOS) to measure respiratory system resistance (Rrs) and reactance (Xrs), and interruption resistance (Rint) to measure respiratory resistance have been introduced. Further study is required to determine the advantage of these methods.

Airway Resistance↗

Racial differences in the association between maternal smoking during pregnancy and lung function in children.

We recently reported that suburban white schoolchildren whose mothers smoked during pregnancy have significantly reduced lung function. Because inner-city and minority children may be at greater risk for respiratory morbidity, we evaluated the relationship between maternal smoking during pregnancy and lung function in 493 white and 383 black schoolchildren 9 to 11 yr of age in three areas of Philadelphia. The child's passive smoking history was determined from reports by the mother. Spirometry was performed at school. After adjusting for height, weight, age, sex, area of city, race, socioeconomic status, and current exposure to environmental tobacco smoke at home, maternal smoking during pregnancy was associated with significant deficits in FEF25-75 (-8.1%) and FEV1/FVC (-2.0%). The observed deficits were larger for black children than for white children, and they were larger for boys than for girls. These results provide additional evidence of an association between maternal smoking during pregnancy and reduced pulmonary function in children, and they suggest that the association may be modified by race and/or sex.

Black People↗

Lung function response to cold air challenge in asthmatic and healthy children of 2-5 years of age.

The aim of the study was to assess feasibility, sensitivity, specificity, predictive value, and repeatability of cold, dry air challenge (CACh) as a diagnostic test for asthma in young children 2 to 5 yr of age. Response to a 4-min single-step isocapnic CACh was measured in 38 asthmatics and 29 control subjects. Specific airway resistance (sRaw) by whole body plethysmography was the primary outcome. In addition, lung function was measured as respiratory resistance by the interrupter technique (Rint) and respiratory resistance and reactance at 5 Hz (Rrs5, Xrs5) by the impulse oscillation technique. At baseline, lung function measures differed significantly between asthmatics and healthy control subjects. CACh was readily performed in young children. Response was expressed as change from baseline in numbers of within-subject standard deviation (SDw). Hyperresponsiveness defined as change in lung function of more than 3 SDw was detected by sRaw in 26 of 38 asthmatics versus 2 of 29 control subjects, by Rint in 12 of 38 asthmatics versus 1 of 29 control subjects, by Xrs5 in 9 of 38 asthmatics versus zero of 29 control subjects and by Rrs5 in 7 of 38 asthmatics versus 1 of 29 control subjects. Thus sRaw had the highest sensitivity (68%). Specificity ranged from 93 to 100%. The correlation coefficient between sRaw responses to CACh repeated within 8 wk was 96%. In conclusion, CACh is feasible in young children age 2 to 5 yr. Whole body plethysmography (sRaw) was superior in separating asthmatics from healthy control subjects. Change in sRaw in response to CACh may be used as a diagnostic test for asthma in young children.

Asthma↗

Do the medical history and physical examination predict low lung function?

BACKGROUND: We sought to determine whether an abnormal respiratory history or chest physical examination could be used to identify men with low lung function. METHODS: We analyzed pulmonary function, physical examination, and questionnaire data from 4461 middle-aged male Vietnam-era army veterans. MAIN RESULTS: The study sample consisted of 1161 never smokers, 1292 former smokers, and 2008 current smokers. Clinical indicators of respiratory disease (respiratory symptoms, respiratory signs, or a history of respiratory disease), were present in 26.1% of the never smokers, 31.7% of the former smokers, and 47.2% of the current smokers. We defined low forced expiratory volume in 1 second as a value less than 81.2% of the predicted value. Seven percent of the never smokers, 8% of the former smokers, and 17.3% of the current smokers demonstrated low forced expiratory volume in 1 second. Among those with a clinical indicator for spirometry only 11% of the never smokers, 13% of the former smokers, and 21% of the current smokers actually had a low forced expiratory volume in 1 second. Among those without a clinical indicator 6% of the never smokers, 6% of the former smokers, and 14% of the current smokers actually had a low forced expiratory volume in 1 second. CONCLUSIONS: The use of clinical indicators as a basis for obtaining pulmonary function tests in middle-aged men misses many with low lung function, especially current smokers.

Adult↗

Methodologic issues in the analysis of lung function data.

The forced expiratory volume in one second (FEV1) is routinely used in epidemiologic studies of lung function to assess the presence and severity of obstructive airways disease. Normative prediction equations developed using data from healthy, asymptomatic individuals may then be used both in a clinical setting and to adjust comparisons among risk subgroups for known demographic differences. Unfortunately no concensus has yet developed as to how best to model lung function data. This paper addresses this issue in a systematic manner using data derived from two cohorts followed over a period of 9-11 years. We compare a variety of cross-sectional and longitudinal models for FEV1, show how they may be expressed as members of a larger class of general linear models, and discuss goodness-of-fit procedures for comparing them. We found little objective evidence for discriminating among these models; only those fit to FEV1/ht3 performed poorly. We argue on subjective grounds for the use of models based on FEV1 as a function of age, height and their interactions.

Adult↗

The effects of environmental tobacco smoke exposure on lung function in a longitudinal study of British adults.

Small effects of environmental tobacco smoke exposure on lung function have been demonstrated in many studies of children, but fewer studies have examined adults in this respect. We examined these relations in a 7-year longitudinal study of 1,623 British adults, age 18-73 years, who were nonsmokers throughout. Outcome was measured by forced expiratory volume in 1 second (FEV1) adjusted for sex, age, and height. Exposure was assessed by asking subjects whether they lived with a smoker (at both the initial and the follow-up studies) and by salivary cotinine measurements (follow-up study only). Cross-sectionally, subjects exposed at home showed tiny FEV1 deficits at both studies of -4 ml [95% confidence limits (CL) = -31, 23] and -5 ml (95% CL = -32, 22), respectively. Cotinine adjusted for potential confounders showed a stronger association with FEV1, with the highest quintile showing a -105-ml deficit (95% CL = -174, -37) in comparison with the lowest. Longitudinally, no clear relation was apparent between change in FEV1 and average exposure or change in exposure. These results indicate that environmental tobacco smoke is associated with small deficits in adult lung function, consistent with our meta-analysis estimate of a 2.7% deficit in exposed nonsmoking adults. The relations seen with cotinine but not with household exposure may reflect the importance of exposure outside the home.

Adolescent↗

Effect of spironolactone-hydrochlorothiazide on lung function in infants with chronic bronchopulmonary dysplasia.

To test the hypothesis that spironolactone-hydrochlorothiazide (Aldactazide) will improve urine output and lung function in infants with bronchopulmonary dysplasia, we studied 21 hospitalized, spontaneously breathing, oxygen-dependent infants with chronic bronchopulmonary dysplasia. Infants were randomly assigned to receive either a 1:1 mixture of spironolactone and hydrochlorothiazide orally (n = 12) (3 mg/kg/day of both compounds) or no treatment (n = 9) for 6 to 8 days each. Dynamic lung compliance, total pulmonary resistance, and hemoglobin oxygen saturation were measured on the first and last days of each study period. Fluid intake and urine output were measured each day. Although the treatment significantly increased urine output, neither lung mechanics nor oxygenation were improved by the drug. The magnitude of the diuresis achieved with spironolactone-hydrochlorothiazide treatment was comparable to the diuresis achieved in a previous study of furosemide treatment (J Pediatr 1986:109;1034-9). Statistical analysis indicated that a type II error was an unlikely explanation for our failure to detect a beneficial effect. In three patients, doubling the oral dose did not improve lung mechanics or oxygenation. We speculate that diuresis per se is not responsible for lung function improvement during treatment with other drugs with diuretic properties.

Bronchopulmonary Dysplasia↗

Lung function and bronchial challenges in infants: repeatability of histamine and comparison with methacholine challenges.

UNLABELLED: Limited information exists regarding the repeatability of lung function and bronchial challenge tests using the rapid thoracic compression technique (RTC) in infants. AIMS: To determine the repeatability of lung function and histamine challenge test results using the RTC technique and to compare the results obtained for bronchial challenges using histamine (H) and methacholine (M). METHODS: Twelve infants [7 healthy, 5 with cystic fibrosis (CF) had pairs of H challenges 1 week apart. Eleven infants (7 healthy, 4 CF) had one H and one M challenge a week apart. The provocative concentration of H or M to cause a 40% fall in maximum flow at functional residual capacity (PC40) was determined using the RTC technique. Twenty-three comparisons were possible between maximal expiratory flow at functional residual capacity (VmaxFRC) measurements made 1 week apart. RESULTS: The mean difference between pairs of VmaxFRC measurements was 6.4% of baseline, and the coefficient of repeatability was 31.1% of baseline. The mean difference between PC40(H) measurements was 0.163 doubling concentrations, with a coefficient of repeatability of 1.66 doubling concentrations. The mean difference between PC40(H) and PC40(M) was 0.75 doubling concentrations, with 95% of PC40(H) between -0.18 to 1.69 doubling concentrations of the PC40(M). CONCLUSIONS: Although the repeatability of VmaxFRC using the RTC technique is less than for voluntary forced expiratory flow parameters in older children, similar results were obtained for infants as observed in older subjects for repeatability of H challenges and agreement between measures of bronchial responsiveness using H or M.

Bronchial Provocation Tests↗