Responsivity and Reproducibility of Sputum Inflammatory Biomarkers During COPD Exacerbation and Stable Phases - A Pilot Study

Introduction

There is a great interest to identify airway biomarkers to evaluate the potential and efficacy of anti-inflammatory therapeutic interventions. In this pilot study, we compared cytokine mRNA and protein levels of IL-6, IL-8, CCL2, CCL4, and TNF-α, as well as LTB-4 expression regarding their reproducibility and responsivity in induced sputum in COPD patients.

Methods

We recruited a cohort of 17 patients with a moderate COPD exacerbation, necessitating antibiotics and/or oral corticosteroids. Patients were followed for two consecutive stable phase visits. Cytokine mRNA and protein levels were measured in induced sputum samples.

Results

IL-6 and CCL4 protein levels decreased from exacerbation to stable phase, whereas their mRNA expression showed the same trend (not statistically significant). Coefficients of variation were overall lower (ie, more favorable for responsiveness) at protein levels compared to mRNA levels. No significant differences were observed in the reproducibility between cytokine mRNA expression and protein measurements. IL-6, IL-8, CCL2, and TNF-α gene expression levels yielded moderate to high intraclass correlation coefficients and/or Spearman correlation coefficients between both stable phase samples in contrast to their protein levels.

Conclusion

Our findings suggest that several protein levels yield better responsivity with lower noise-to-signal ratios compared to their respective mRNA levels. In contrast, cytokine mRNA expression was more reproducible as it varied less in a stable state than proteins. Future studies are needed with a larger sample size to further evaluate the differences of responsivity and reproducibility between cytokine mRNA and protein measurements, not only during exacerbations.

Colistin dry powder inhalation with the Twincer™: An effective and more patient friendly alternative to nebulization

Background

Nebulization of antimicrobial drugs such as tobramycin and colistin is a cornerstone in the treatment of patients with cystic fibrosis (CF) infected with Pseudomonas aeruginosa. However, nebulization has a high treatment burden. The Twincer^™ is a dry powder inhaler specifically developed for the inhalation of antibiotics such as colistin. The aim of this study was to compare patient outcomes and experience with colistin dry powder by the Twincer with nebulization of colistin or tobramycin in adult CF patients in a real-life setting.

Methods

This was a retrospective study from 01-01-2015 until 01-07-2018. Effectiveness was evaluated by comparing FEV₁ decline and exacerbation rate during a mean of 4.1 years of nebulization therapy prior to the initiation of the Twincer against the same values during a mean of 1.7 years of treatment with the Twincer.

Results

Twenty-one patients were evaluated, of whom twelve could be included in the effectiveness analysis, with a total of twenty patient years. Of all patients 71.4% preferred therapy with the Twincer over nebulization. Twincer use resulted in high treatment adherence with an average adherence rate of 92.5%. There was no significant difference in annual decline in FEV₁%pred prior to and after start changing from nebulization to the use of the Twincer powder inhaler (median decline -1.56 [-5.57–5.31] and 1.35 [-8.45–6.36]) respectively, p = 0.45 (linear mixed effect model)). No significant difference was found in the number of intravenous or combined total intravenous and oral antibiotic courses during Twincer therapy compared to when using nebulization (1.68 and 2.49 courses during Twincer therapy versus 1.51 and 2.94 courses during nebulization, p = 0.88 and p = 0.63).

Conclusion

Colistin dry powder inhalation with the Twincer is a more patient friendly alternative to nebulization, and we did not observe significant differences in the clinical outcome, regarding lung function and exacerbation rates.

Determinants of SARS-CoV-2 receptor gene expression in upper and lower airways

The recent outbreak of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has led to a worldwide pandemic. One week after initial symptoms develop, a subset of patients progresses to severe disease, with high mortality and limited treatment options. To design novel interventions aimed at preventing spread of the virus and reducing progression to severe disease, detailed knowledge of the cell types and regulating factors driving cellular entry is urgently needed. Here we assess the expression patterns in genes required for COVID-19 entry into cells and replication, and their regulation by genetic, epigenetic and environmental factors, throughout the respiratory tract using samples collected from the upper (nasal) and lower airways (bronchi). Matched samples from the upper and lower airways show a clear increased expression of these genes in the nose compared to the bronchi and parenchyma. Cellular deconvolution indicates a clear association of these genes with the proportion of secretory epithelial cells. Smoking status was found to increase the majority of COVID-19 related genes including ACE2 and TMPRSS2 but only in the lower airways, which was associated with a significant increase in the predicted proportion of goblet cells in bronchial samples of current smokers. Both acute and second hand smoke were found to increase ACE2 expression in the bronchus. Inhaled corticosteroids decrease ACE2 expression in the lower airways. No significant effect of genetics on ACE2 expression was observed, but a strong association of DNA- methylation with ACE2 and TMPRSS2- mRNA expression was identified in the bronchus.

Novel genes and insights in complete asthma remission: A genome-wide association study on clinical and complete asthma remission

BACKGROUND

Asthma is a chronic respiratory disease without a cure, although there exists spontaneous remission. Genome-wide association (GWA) studies have pinpointed genes associated with asthma development, but did not investigate asthma remission.

OBJECTIVE

We performed a GWA study to develop insights in asthma remission.

METHODS

Clinical remission (ClinR) was defined by the absence of asthma treatment and wheezing in the last year and asthma attacks in the last 3 years and complete remission (ComR) similarly but additionally with normal lung function and absence of bronchial hyperresponsiveness (BHR). A GWA study on both ClinR and ComR was performed in 790 asthmatics with initial doctor diagnosis of asthma and BHR and long-term follow-up. We assessed replication of the 25 top single nucleotide polymorphisms (SNPs) in 2 independent cohorts (total n = 456), followed by expression quantitative loci (eQTL) analyses of the 4 replicated SNPs in lung tissue and epithelium.

RESULTS

Of the 790 asthmatics, 178 (23%) had ClinR and 55 ComR (7%) after median follow-up of 15.5 (range 3.3-47.8) years. In ClinR, 1 of the 25 SNPs, rs2740102, replicated in a meta-analysis of the replication cohorts, which was an eQTL for POLI in lung tissue. In ComR, 3 SNPs replicated in a meta-analysis of the replication cohorts. The top-hit, rs6581895, almost reached genome-wide significance (P-value 4.68 × 10^-7 ) and was an eQTL for FRS2 and CCT in lung tissue. Rs1420101 was a cis-eQTL in lung tissue for IL1RL1 and IL18R1 and a trans-eQTL for IL13.

CONCLUSIONS AND CLINICAL RELEVANCE

By defining a strict remission phenotype, we identified 3 SNPs to be associated with complete asthma remission, where 2 SNPs have plausible biological relevance in FRS2, CCT, IL1RL1, IL18R1 and IL13.

Genes and pathways underlying susceptibility to impaired lung function in the context of environmental tobacco smoke exposure

Background

Studies aiming to assess genetic susceptibility for impaired lung function levels upon exposure to environmental tobacco smoke (ETS) have thus far focused on candidate-genes selected based on a-priori knowledge of potentially relevant biological pathways, such as glutathione S-transferases and ADAM33. By using a hypothesis-free approach, we aimed to identify novel susceptibility loci, and additionally explored biological pathways potentially underlying this susceptibility to impaired lung function in the context of ETS exposure.

Methods

Genome-wide interactions of single nucleotide polymorphism (SNP) by ETS exposure (0 versus ≥1 h/day) in relation to the level of forced expiratory volume in one second (FEV₁) were investigated in 10,817 subjects from the Dutch LifeLines cohort study, and verified in subjects from the Swiss SAPALDIA study (n = 1276) and the Dutch Rotterdam Study (n = 1156). SNP-by-ETS exposure p-values obtained from the identification analysis were used to perform a pathway analysis.

Results

Fourty Five SNP-by-ETS exposure interactions with p-values <10⁻⁴ were identified in the LifeLines study, two being replicated with nominally significant p-values (<0.05) in at least one of the replication cohorts. Three pathways were enriched in the pathway-level analysis performed in the identification cohort LifeLines, i.E. the apoptosis, p38 MAPK and TNF pathways.

Conclusion

This unique, first genome-wide gene-by-ETS interaction study on the level of FEV₁ showed that pathways previously implicated in chronic obstructive pulmonary disease (COPD), a disease characterized by airflow obstruction, may also underlie susceptibility to impaired lung function in the context of ETS exposure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0625-7) contains supplementary material, which is available to authorized users.

PTTG1IP and MAML3, novel genomewide association study genes for severity of hyperresponsiveness in adult asthma

BACKGROUND

The severity of bronchial hyperresponsiveness (BHR) is a fundamental feature of asthma. The severity of BHR varies between asthmatics and is associated with lack of asthma control. The mechanisms underlying this trait are still unclear. This study aimed to identify genes associated with BHR severity, using a genomewide association study (GWAS) on the slope of BHR in adult asthmatics.

METHODS

We performed a GWAS on BHR severity in adult asthmatics from the Dutch Asthma GWAS cohort (n = 650), adjusting for smoking and inhaled corticosteroid use, and verified results in three other cohorts. Furthermore, we performed eQTL and co-expression analyses in lung tissue.

RESULTS

In the discovery cohort, one genomewide significant hit located in phosphodiesterase 4D, cAMP-specif (PDE4D) and 26 SNPs with P-values < 1*10^-5 were found. None of our findings replicated in adult and childhood replication cohorts jointly. In adult cohorts separately, rs1344110 in pituitary tumour-transforming 1 interacting protein (PTTG1IP) and rs345983 in Mastermind-like 3 (MAML3) replicated nominally; minor alleles of rs345983 and rs1344110 were associated with less severe BHR and higher lung tissue gene expression. PTTG1IP showed significant co-expression with pituitary tumour-transforming 1, the binding factor of PTTG1lP, and with vimentin and E-cadherin1. MAML3 co-expressed significantly with Mastermind-like 2 (MAML2), both involved in Notch signalling.

CONCLUSIONS

PTTG1IP and MAML3 are associated with BHR severity in adult asthma. The relevance of these genes is supported by the eQTL analyses and co-expression of PTTG1lP with vimentin and E-cadherin1, and MAML3 with MAML2.

Combining genomewide association study and lung eQTL analysis provides evidence for novel genes associated with asthma

BACKGROUND

Genomewide association studies (GWASs) of asthma have identified single-nucleotide polymorphisms (SNPs) that modestly increase the risk for asthma. This could be due to phenotypic heterogeneity of asthma. Bronchial hyperresponsiveness (BHR) is a phenotypic hallmark of asthma. We aim to identify susceptibility genes for asthma combined with BHR and analyse the presence of cis-eQTLs among replicated SNPs. Secondly, we compare the genetic association of SNPs previously associated with (doctor's diagnosed) asthma to our GWAS of asthma with BHR.

METHODS

A GWAS was performed in 920 asthmatics with BHR and 980 controls. Top SNPs of our GWAS were analysed in four replication cohorts, and lung cis-eQTL analysis was performed on replicated SNPs. We investigated association of SNPs previously associated with asthma in our data.

RESULTS

A total of 368 SNPs were followed up for replication. Six SNPs in genes encoding ABI3BP, NAF1, MICA and the 17q21 locus replicated in one or more cohorts, with one locus (17q21) achieving genomewide significance after meta-analysis. Five of 6 replicated SNPs regulated 35 gene transcripts in whole lung. Eight of 20 asthma-associated SNPs from previous GWAS were significantly associated with asthma and BHR. Three SNPs, in IL-33 and GSDMB, showed larger effect sizes in our data compared to published literature.

CONCLUSIONS

Combining GWAS with subsequent lung eQTL analysis revealed disease-associated SNPs regulating lung mRNA expression levels of potential new asthma genes. Adding BHR to the asthma definition does not lead to an overall larger genetic effect size than analysing (doctor's diagnosed) asthma.

Patterns of Growth and Decline in Lung Function in Persistent Childhood Asthma

BACKGROUND

Tracking longitudinal measurements of growth and decline in lung function in patients with persistent childhood asthma may reveal links between asthma and subsequent chronic airflow obstruction.

METHODS

We classified children with asthma according to four characteristic patterns of lung-function growth and decline on the basis of graphs showing forced expiratory volume in 1 second (FEV1), representing spirometric measurements performed from childhood into adulthood. Risk factors associated with abnormal patterns were also examined. To define normal values, we used FEV1 values from participants in the National Health and Nutrition Examination Survey who did not have asthma.

RESULTS

Of the 684 study participants, 170 (25%) had a normal pattern of lung-function growth without early decline, and 514 (75%) had abnormal patterns: 176 (26%) had reduced growth and an early decline, 160 (23%) had reduced growth only, and 178 (26%) had normal growth and an early decline. Lower baseline values for FEV1, smaller bronchodilator response, airway hyperresponsiveness at baseline, and male sex were associated with reduced growth (P<0.001 for all comparisons). At the last spirometric measurement (mean [±SD] age, 26.0±1.8 years), 73 participants (11%) met Global Initiative for Chronic Obstructive Lung Disease spirometric criteria for lung-function impairment that was consistent with chronic obstructive pulmonary disease (COPD); these participants were more likely to have a reduced pattern of growth than a normal pattern (18% vs. 3%, P<0.001).

CONCLUSIONS

Childhood impairment of lung function and male sex were the most significant predictors of abnormal longitudinal patterns of lung-function growth and decline. Children with persistent asthma and reduced growth of lung function are at increased risk for fixed airflow obstruction and possibly COPD in early adulthood. (Funded by the Parker B. Francis Foundation and others; ClinicalTrials.gov number, NCT00000575.).

Long-term exposure to circulating platinum is associated with late effects of treatment in testicular cancer survivors

Cisplatin is an essential part of testicular cancer treatment. We investigated whether long-term exposure to circulating platinum (Pt) plays a role in the development of late effects in survivors. We assessed Pt decay in samples collected 1–13 years after chemotherapy. Renal function is a strong determinant of exposure to Pt. Higher exposure to Pt is associated with an increased prevalence of adverse effects hypogonadism and hypertension.

Background

The success of cisplatin-based (Platinol, Bristol-Myers Squibb Company, New York, NY, USA) chemotherapy for testicular cancer comes at the price of long-term and late effects related to healthy tissue damage. We assessed and modelled serum platinum (Pt) decay after chemotherapy and determined relationships between long-term circulating Pt levels and known late effects.

Patients and methods

In 99 testicular cancer survivors, treated with cisplatin-based chemotherapy, serum and 24-h urine samples were collected during follow-up (1–13 years after treatment). To build a population pharmacokinetic model, measured Pt data were simultaneously analysed, together with cisplatin dose, age, weight and height using the NONMEM software. Based on this model, area under the curve between 1 and 3 years after treatment (Pt AUC_{1–3 years}) was calculated for each patient. Predicted long-term Pt exposure was related to renal function and to late effects of treatment assessed median 9 (3–15) years after chemotherapy.

Results

Decay of Pt was best described by a two-compartment model. Mean terminal T_1/2 was 3.7 (range 2.5–5.2) years. Pt AUC_{1–3 years} correlated with cumulative cisplatin dose, and creatinine clearance before and 1 year after treatment. Patients with paraesthesia had higher Pt AUC_{1–3 years} (30.9 versus 27.0 µg/l month) compared with those without paraesthesia (P = 0.021). Patients with hypogonadism, elevated LDL-cholesterol levels or hypertension also had higher Pt AUC_{1–3 years}.

Conclusions

Renal function before and after cisplatin treatment is an important determinant of long-term Pt exposure. Known long-term effects of testicular cancer treatment, such as paraesthesia, hypogonadism, hypercholesterolaemia and hypertension, are associated with long-term circulating Pt exposure.

VEGFA variants are associated with pre-school lung function, but not neonatal lung function

BACKGROUND

Vascular endothelial growth factor (VEGF) is implicated in airway remodelling and asthma development. We studied VEGFA gene variants and plasma levels and the development of lung function, bronchial hyperresponsiveness and asthma in childhood.

METHODS

We analysed 13 SNPs in the VEGFA gene in 411 children from the COPSAC2000 high-risk birth cohort. Asthma was diagnosed prospectively, and lung function measurements were obtained at birth and 6 years of age. Plasma VEGF levels were measured at 18 months of age. We used a Bonferroni adjusted significance level. Findings were replicated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort at age 8.

RESULTS

At age six, three SNPs from the same linkage block were associated with FEV1 (rs699947, P = 1.31E-05), independent of asthma, and there were suggestive associations between FEV1/FVC ratio and rs833052 and maximal mid-expiratory flow and rs6900017. Replication in the PIAMA cohort showed borderline association between FEV1 and rs699947 and significant meta-analysis result. SNPs upstream and nearby rs699947 were nominally associated with VEGF plasma levels. VEGF levels were not associated with asthmatic symptoms or lung function measures.

CONCLUSIONS AND CLINICAL RELEVANCE

VEGF gene variants are associated with lung function at school age, but not at birth, suggesting a role of VEGF in post-natal lung function development.

Nocturnal non-invasive ventilation in COPD patients with prolonged hypercapnia after ventilatory support for acute respiratory failure: a randomised, controlled, parallel-group study

INTRODUCTION

The effectiveness of non-invasive positive pressure ventilation (NIV) in COPD patients with prolonged hypercapnia after ventilatory support for acute respiratory failure (ARF) remains unclear. We investigated if nocturnal NIV in these patients prolongs the time to readmission for respiratory causes or death (primary endpoint) in the following 12 months.

METHODS

201 COPD patients admitted to hospital with ARF and prolonged hypercapnia >48 h after termination of ventilatory support were randomised to NIV or standard treatment. Secondary outcomes were daytime arterial blood gasses, transcutaneous PCO2 during the night, lung function, health-related quality-of-life (HRQL), mood state, daily activities and dyspnoea.

RESULTS

1 year after discharge, 65% versus 64% of patients (NIV vs standard treatment) were readmitted to hospital for respiratory causes or had died; time to event was not different (p=0.85). Daytime PaCO2 was significantly improved in NIV versus standard treatment (PaCO2 0.5 kPa (95% CI 0.04 to 0.90, p=0.03)) as was transcutaneous PCO2 during the night. HRQL showed a trend (p=0.054, Severe Respiratory Insufficiency questionnaire) in favour of NIV. Number of exacerbations, lung function, mood state, daily activity levels or dyspnoea was not significantly different.

DISCUSSIONS

We could not demonstrate an improvement in time to readmission or death by adding NIV for 1 year in patients with prolonged hypercapnia after an episode of NIV for ARF. There is no reason to believe the NIV was not effective since daytime PaCO2 and night-time PCO2 improved. The trend for improvement in HRQL favouring NIV we believe nevertheless should be explored further.

TRIAL REGISTRATION NUMBER

NTR1100.

E-cadherin gene polymorphisms in asthma patients using inhaled corticosteroids

E-cadherins form intercellular junctions that maintain epithelial integrity. Epithelial integrity is impaired in asthma and can be restored by inhaled corticosteroids (ICSs). Our aim was to investigate the association of CDH1 gene polymorphisms (single-nucleotide polymorphisms (SNPs)) with airway remodelling, inflammation and forced expiratory volume in 1 s (FEV₁) decline in asthma patients and assess whether ICSs modulate these effects. Bronchial biopsies of 138 asthmatics were available (population 1). Associations of 17 haplotype-tagging SNPs with epithelial E-cadherin expression, biopsy parameters and FEV₁/vital capacity (VC) ratio were tested. FEV₁ and VC data were collected in 281 asthmatics with 30-yr follow-up (population 2). Linear mixed-effect models were used to assess associations of SNPs with FEV₁ decline. Seven out of the 17 SNPs were associated with airway remodelling, three with CD8+ T-cell counts, two with eosinophil counts and seven with FEV₁ decline. All associations occurred only in patients using ICS. In general, alleles associated with less remodelling correlated with less FEV₁ decline and higher FEV₁/VC. Decreased epithelial E-cadherin expression was associated with five SNPs in non-ICS users. In conclusion, our data show that CDH1 polymorphisms are associated with epithelial E-cadherin expression and suggest that epithelial adhesion is an important contributor to airway remodelling and lung function in asthma. These effects are modified by the use of inhaled corticosteroids.

SERPINE1 -675 4G/5G polymorphism is associated with asthma severity and inhaled corticosteroid response

Asthma is characterised by chronic airway inflammation and remodelling, which can be (partially) suppressed by inhaled corticosteroids (ICSs). Plasminogen activator inhibitor-1, encoded by the SERPINE1 gene, is the key inhibitor of the plasminogen activator system, which affects tissue repair and remodelling. We studied associations between a functional SERPINE1 -675 4G/5G promoter polymorphism and asthma development, severity and response to ICSs. Longitudinal cohorts of 281 asthmatics and their nonasthmatic spouses, and the general population (n=1,390) were studied. No significant associations were found with asthma development and immunoglobulin (Ig)E levels, or with forced expiratory volume in 1 s (FEV₁) in nonasthmatic controls. Asthmatic subjects carrying the SERPINE1 5G allele had higher IgE and lower lung function levels at follow-up, lower maximally attained lung function levels, and faster lung function decline compared with individuals with the 4G/4G genotype. ICS treatment showed an immediate improvement in FEV₁ in asthmatics carrying the 5G allele. However, these asthmatics still had the fastest rate of FEV₁ decline after initiating ICS treatment. Finally, the 5G allele was associated with a lower prevalence of complete asthma remission at follow-up. These findings suggest that SERPINE1 is not an asthma susceptibility gene, but rather affects the severity, progression and long-term ICS response in asthma.

Particle size matters: diagnostics and treatment of small airways involvement in asthma

Small airways are an important site of inflammation and obstruction in asthma, which contributes to the severity of airway hyperresponsiveness (AHR) that is usually measured by nebulisation of large-particle stimuli. We investigated whether small and large particle sizes of aerosolised adenosine monophospate (AMP) provoke similar severity of AHR. Additionally, effects of the small-particle inhaled corticosteroid (ICS) ciclesonide and large-particle ICS fluticasone on AHR to large- and small-particle size AMP were assessed. After a 4-week run-in period using open-label fluticasone (100 μg b.i.d.), 37 mild-to-moderate asthmatics underwent provocations with standard-size (3.7 μm), large-particle (9.9 μm) and small-particle (1.06 μm) AMP. Subjects received 4-week ciclesonide (160 μg s.i.d.) or fluticasone (100 μg b.i.d.) treatment (double-blind and double-dummy) followed by large- and small-particle AMP provocation. Small-particle AMP induced a 20% decrease in forced expiratory volume in 1 s (FEV(1)) at a significantly higher dose than large-particle AMP. Ciclesonide and fluticasone had comparable effects on AMP provocations. Not all subjects reached the provocative concentration causing a 20% fall in FEV(1) (PC(20)) at the highest AMP dose. In those who did, ciclesonide improved small-particle AMP PC(20) by 1.74 doubling doses (DD) (p = 0.03), whereas fluticasone did not. Conversely, fluticasone improved large-particle AMP PC(20) significantly (1.32 DD; p = 0.03), whereas ciclesonide did not. Small-particle AMP provocation appears to be a promising tool to assess changes in small airway inflammation. Future adjustments are necessary taking into account the very small particle size used, with large exhaled fractions. In asthmatics reaching a PC(20) with small- and large-particle AMP provocations, ciclesonide improves hyperresponsiveness to small particle size AMP, and fluticasone to large particle size. This warrants further research to target provocations and treatment to specific airway sizes.

Ciclesonide improves measures of small airway involvement in asthma

Ciclesonide is delivered as a small-particle inhaled corticosteroid and improves lung function and airway hyperresponsiveness. The objective of the present study was to assess whether ciclesonide can specifically improve small airway function in asthma. A total of 16 mild-to-moderate asthma patients (seven males; median (range) age 39 (19-56) yrs and forced expiratory volume in one second (FEV(1)) 89 (62-120)% predicted) were randomised to 5 weeks' treatment with placebo or 320 mug ciclesonide once daily. The following small airway parameters were assessed: mean forced expiratory flow between 25 and 75% of forced vital capacity (FVC), percentage fall in FVC at provocative dose of adenosine-5'-monophosphate and of methacholine (MCh) causing a 20% fall in FEV(1), expiratory lung volume on computed tomography (CT) scan after MCh challenge, single-breath nitrogen closing volume and alveolar exhaled nitric oxide (eNO). Seven subjects received placebo and nine received ciclesonide. Both alveolar eNO and CT measurements of expiratory lung volume after MCh challenge decreased significantly with ciclesonide (median (range) decrease 4.4 (54.8-1.4) ppb and 59 (1,569- -117) mL, respectively), and compared with placebo (-0.4 (7.3- -3.4) ppb and -121 (20- -236) mL respectively). Ciclesonide did not significantly improve other small airways parameters. Inflammation and patency of small airways, reflected by alveolar exhaled nitric oxide and air trapping on computed tomography scan, both improve with ciclesonide even in this small number of patients. This indicates that ciclesonide exerts anti-inflammatory effects on small airways.

Severe exacerbations predict excess lung function decline in asthma

Severe asthma exacerbations are periods of intense airway inflammation that have been hypothesised to contribute to structural changes in the airways. If so, accelerated lung function decline over time should be more prevalent in adult patients with asthma who have frequent exacerbations than those without, but to date this has not been demonstrated. A cohort study was performed in order to investigate the effect of severe exacerbations on the progression of airway obstruction in 93 nonsmoking asthmatics with moderate-to-severe disease prior to treatment with inhaled corticosteroids. Subjects were followed for > or =5 yrs (median follow-up 11 yrs). In total, 56 (60.2%) subjects experienced at least one severe exacerbation (median rate 0.10.yr(-1)). Oral corticosteroid use and more severe airway obstruction at baseline were associated with a higher exacerbation rate. Independent of these variables, asthma patients with frequent exacerbations had a significantly larger annual decline in forced expiratory volume in one second (FEV(1); median difference (95% confidence interval) 16.9 (1.5-32.2) mL.yr(-1)). Exacerbation rate significantly predicted an excess decline in FEV(1), such that one severe exacerbation per year was associated with a 30.2 mL greater annual decline in FEV(1). These data support the hypothesis that exacerbations, indicating intermittent periods of worsening airway inflammation, are associated with excess lung function decline in asthma.

Long-term cardiac follow-up in survivors of a malignant bone tumour

BACKGROUND

Longitudinal studies of cardiac function in long-term childhood cancer survivors are scarce and frequently concern a median follow-up shorter than 13 years.

PATIENTS AND METHODS

Cardiac assessment was performed in 22 doxorubicin-treated long-term survivors of a malignant bone tumour at median 22 years (range 15-27.5) post-treatment. Age at follow-up was 39 years (range 27-59) and cumulative dose of doxorubicin was 360 mg/m(2) (range 225-550). Cardiac function was assessed by echocardiography and (24-h) ECG. The results were compared with those of earlier assessments at 9 years (1992) and 14 years (1997) post-treatment.

RESULTS

Systolic dysfunction was found in 27% (9% in 1997; P = 0.02) and diastolic dysfunction in 45% (18% in 1997; P = 0.02). Heart rate variability showed further deterioration compared with earlier results.

CONCLUSIONS

Twenty-two years after doxorubicin-treatment, bone tumour survivors showed progressive cardiac dysfunction.

Lung function decline in asthma: association with inhaled corticosteroids, smoking and sex

BACKGROUND

Inhaled corticosteroids (ICS) provide short term benefits in asthma but the long term effects are still unknown.

METHODS

281 patients diagnosed with moderate to severe asthma in 1963-75 were re-examined in 1991-9. Information was collected on forced expiratory volume in 1 second (FEV(1)), bronchial hyperresponsiveness, atopy, smoking, use and dosage of oral and ICS. Patients were included in the analyses if they had at least three FEV(1) measurements during two consecutive years after the age of 30 and used ICS during follow up.

RESULTS

Analyses were performed on 122 patients. During a median follow up period of 23 years, 71 men and 51 women had on average 37 and 40 individual FEV(1) measurements, respectively. Linear mixed effect models showed that men had a mean annual decline in FEV(1) of 20.6 ml/year less after ICS initiation than before (p = 0.011), and in women the decline in FEV(1) was 3.2 ml/year less (p = 0.73). In individuals with <5 pack years of smoking the decline in FEV(1) was 36.8 ml/year less after ICS institution in men (p = 0.0097) and 0.8 ml/year less in women (p = 0.94), the difference between the sexes being significant (p = 0.045). These effects were not observed in those with > or =5 pack years smoking. A higher daily dose of ICS was associated with a smaller decline in FEV(1) in men (p = 0.006), an effect not observed in women.

CONCLUSION

Treatment with ICS in adult patients with moderate to severe asthma was associated with a reduction in the decline in FEV(1) over a 23 year follow up period in men who had smoked <5 pack years. This effect was dose dependent and was not present in women or in men with > or =5 pack years of smoking at follow up. The lack of effect of ICS on the decline in FEV(1) in women needs further study.

Predictors of lung function and its decline in mild to moderate COPD in association with gender: results from the Euroscop study

BACKGROUND

There is increasing appreciation of gender differences in COPD but scant data whether risk factors for low lung function differ in men and women. We analysed data from 3 years follow-up in 178 women and 464 men with COPD, participants in the Euroscop Study who were smokers unexposed to inhaled corticosteroids.

METHODS

Explanatory variables of gender, age, starting age and pack-years smoking, respiratory symptoms, FEV(1)%FVC and FEV(1)%IVC (clinically important measures of airway obstruction), body mass index (BMI), and change in smoking were included in multiple linear regression models with baseline and change in post-bronchodilator FEV(1) as dependent variables.

RESULTS

Reduced baseline FEV(1) was associated with respiratory symptoms in men only. Annual decline in FEV(1) was not associated with respiratory symptoms in either men or women, and was 55 ml less in obese men (BMI 30 kg/m(2)) than men having normal BMI, an effect not seen in women. It was 32 ml faster in women with FEV(1)%FVC<median than women with less airway obstruction, a larger difference than in men (8 ml per year). It was 17.7 ml/year faster when increasing the daily number of cigarettes by 10 in men only, but not significantly greater than in women.

CONCLUSION

Respiratory symptoms were associated with reduced baseline FEV(1) in men with COPD. In men, obesity was associated with reduced decline and increasing the number of cigarettes smoked with increased decline in lung function. In women more severe airway obstruction was associated with accelerated decline.

Susceptibility to air pollution in elderly males and females

It is important to know which individuals in the general population have increased susceptibility to air pollution. The aim of this study was to identify susceptible subgroups by studying airways hyperresponsiveness (AHR), high total immunoglobulin (Ig)E and sex. Diary data on lower and upper respiratory symptoms (LRS and URS, respectively), cough, and morning and evening peak expiratory flow (PEF) were collected in 327 elderly patients (50-70 yrs) for a period of 3 months. Acute effects of particulate matter with a diameter <10 microm, black smoke, sulphur dioxide and nitrogen dioxide on symptoms and PEF were estimated using logistic regression. In total, 48 (14.7%) subjects had AHR+/IgE+, 112 (34.3%) had AHR-/IgE+, 42 (12.8%) had AHR+/IgE- and 125 (38.2%) had AHR-/IgE-. In the AHR+/IgE+ group, each 10 microg x m(-3) increase in air pollution was associated with a significant increase in prevalence of URS (odds ratio ranging 1.03-1.19), cough (1.03-1.08) and fall in morning PEF (1.04-1.26). In the AHR+/IgE+ group, males responded predominantly with symptoms and females with a fall in morning PEF. In conclusion, elderly individuals with both airway hyperresponsiveness and high total immunoglobulin E are especially susceptible to air pollution. Identifying susceptible subgroups might enlarge insight into the actual mechanisms by which air pollution evokes specific modes of response.

Childhood factors associated with asthma remission after 30 year follow up

BACKGROUND

Factors contributing to either "complete" or "clinical" remission of asthma are important to know since there is no cure for the disease.

METHODS

A cohort of 119 allergic asthmatic children was examined three times with a mean follow up of 30 years. They were aged 5-14 years at visit 1 (1966-9), 21-33 years at visit 2 (1983-6), and 32-42 years at visit 3 (1995-6). Complete remission of asthma at visit 3 was defined as no asthma symptoms, no use of inhaled corticosteroids, normal lung function (FEV1 >90% predicted), and no bronchial hyperresponsiveness (PC10 >16 mg/ml). Clinical remission was defined as no asthma symptoms and no use of inhaled corticosteroids.

RESULTS

22% of the group was in complete remission of asthma at visit 3 and a further 30% was in clinical remission (total 52%); 57% of subjects in clinical remission had bronchial hyperresponsiveness and/or a low lung function. Logistic regression analyses showed that a higher FEV1 in childhood and more improvement in FEV1 from age 5-14 to 21-33 were associated with both complete and clinical asthma remission at age 32-42.

CONCLUSIONS

Complete remission of asthma was present in a small subset of asthmatics while half the subjects showed clinical remission. Both complete and clinical remission were associated with a higher lung function level in childhood and a higher subsequent increase in FEV1. These results support the view that defining remission only on the basis of symptoms and medication use will overlook subjects with subclinical active disease and possibly associated airway remodelling.

Polymorphisms of the ADAM33 gene are associated with accelerated lung function decline in asthma

BACKGROUND

Asthma is a genetically complex disease characterized by respiratory symptoms, intermittent airway obstruction and airway hyper-responsiveness due to airway inflammation and remodelling. The ADAM33 gene is associated with asthma and airway hyper-responsiveness and is postulated as a gene for airway remodelling.

OBJECTIVE

To investigate whether polymorphisms of the ADAM33 gene are associated with accelerated lung function decline in patients with asthma.

METHODS

In a cohort of 200 asthma patients followed over 20 years, eight single nucleotide polymorphisms of the ADAM33 gene were analysed to estimate their effect on annual FEV(1) decline.

RESULTS

The rare allele of the S_2 polymorphism was significantly associated with excess decline in FEV(1) (P<0.05).

CONCLUSION

These findings suggest that a variant in ADAM33 is not only important in the development of asthma but also in disease progression, possibly related to enhanced airway remodelling.

Respiratory effects of sulphur dioxide: a hierarchical multicity analysis in the APHEA 2 study

BACKGROUND

Sulphur dioxide (SO(2)) was associated with hospital admissions for asthma in children in the original APHEA study, but not with other respiratory admissions.

AIMS

To assess the association between daily levels of SO(2) and daily levels of respiratory admissions in a larger and more recent study.

METHODS

Time series of daily counts of hospital emergency admissions were constructed for asthma at ages 0-14 years and 15-64 years, COPD and asthma, and all respiratory admissions at ages 65+ years in the cities of Birmingham, London, Milan, Paris, Rome, Stockholm, and in the Netherlands for periods of varying duration between the years 1988 and 1997. A two stage hierarchical modelling approach was used. In the first stage generalised additive Poisson regression models were fitted in each city controlling for weather and season. These results were then combined across cities in a second stage ecological regression that looked at potential effect modifiers.

RESULTS

For an increase of 10 micro g/m(3) of SO(2) the daily number of admissions for asthma in children increased 1.3% (95% CI 0.4% to 2.2%). Effect modification among cities by levels of other air pollutants or temperature was not found. The SO(2) effect disappeared after controlling for PM(10) or CO, but correlation among these pollutants was very high. Other respiratory admissions were not associated with SO(2).

CONCLUSION

SO(2) is associated with asthma admissions in children, indicating that reduction in current air pollution levels could lead to a decrease in the number of asthma admissions in children in Europe.

Risk factors associated with the presence of irreversible airflow limitation and reduced transfer coefficient in patients with asthma after 26 years of follow up

BACKGROUND

Childhood asthma is generally believed to be a disorder with a good prognosis. However, some asthmatics develop irreversible airway obstruction, probably as a result of airway remodelling.

METHODS

After 21-33 years, 228 adults (aged 13-44 years at baseline) with a history of asthma were re-examined to assess risk factors for the development of irreversible airway obstruction (IAO, forced expiratory volume in 1 second (FEV(1)) <80% predicted and reversibility <9% predicted) and a reduced postbronchodilator transfer coefficient (carbon monoxide transfer factor/alveolar volume, <80% predicted), both characteristics of COPD.

RESULTS

At follow up, 41% did not have airway obstruction (NAO), 43% had reversible airway obstruction (RAO), and 16% had IAO; 23% had a reduced transfer coefficient. Patients with RAO had asthma-like characteristics (wheezing, asthma attacks, bronchial hyperresponsiveness (BHR)) while patients with IAO had COPD-like symptoms (cough, phlegm, dyspnoea) at follow up. The development of IAO is determined by a lower FEV(1), less reversibility of airway obstruction and, surprisingly, less severe BHR at initial screening. Eighty percent of the patients with asthma who used anti-inflammatory medication still had airway obstruction, but IAO developed less frequently. Smoking was associated with a reduced transfer coefficient but not with the development of IAO. Female sex was associated with a reduced transfer coefficient, whereas corticosteroid use was not.

CONCLUSIONS

Although IAO and a low transfer coefficient are both characteristics of COPD, they represent distinct entities in adult asthmatics in terms of symptomatology, aetiology, and probably in therapeutic approaches and disease prevention.

Short-term effects of particulate air pollution on cardiovascular diseases in eight European cities

STUDY OBJECTIVE

As part of the APHEA project this study examined the association between airborne particles and hospital admissions for cardiac causes (ICD9 390-429) in eight European cities (Barcelona, Birmingham, London, Milan, the Netherlands, Paris, Rome, and Stockholm). All admissions were studied, as well as admissions stratified by age. The association for ischaemic heart disease (ICD9 410-413) and stroke (ICD9 430-438) was also studied, also stratified by age.

DESIGN

Autoregressive Poisson models were used that controlled for long term trend, season, influenza epidemics, and meteorology to assess the short-term effects of particles in each city. The study also examined confounding by other pollutants. City specific results were pooled in a second stage regression to obtain more stable estimates and examine the sources of heterogeneity.

MAIN RESULTS

The pooled percentage increases associated with a 10 micro g/m(3) increase in PM(10) and black smoke were respectively 0.5% (95% CI: 0.2 to 0.8) and 1.1% (95% CI: 0.4 to 1.8) for cardiac admissions of all ages, 0.7% (95% CI: 0.4 to 1.0) and 1.3% (95% CI: 0.4 to 2.2) for cardiac admissions over 65 years, and, 0.8% (95% CI: 0.3 to 1.2) and 1.1% (95% CI: 0.7 to 1.5) for ischaemic heart disease over 65 years. The effect of PM(10) was little changed by control for ozone or SO(2), but was substantially reduced (CO) or eliminated (NO(2)) by control for other traffic related pollutants. The effect of black smoke remained practically unchanged controlling for CO and only somewhat reduced controlling for NO(2).

CONCLUSIONS

These effects of particulate air pollution on cardiac admissions suggest the primary effect is likely to be mainly attributable to diesel exhaust. Results for ischaemic heart disease below 65 years and for stroke over 65 years were inconclusive.

Perinatal predictors of respiratory symptoms and lung function at a young adult age

A longitudinal cohort of 2,957 babies, born in 1975-1978, was used to investigate whether perinatal factors predict respiratory morbidity at a young adult age. In 1997, the presence of asthmatic (wheeze, nocturnal dyspnoea) and bronchitic (cough, phlegm, dyspnoea grade 3) symptoms and the level of lung function was determined in this cohort. The independent association between smoking during pregnancy, being first-born, birth weight and respiratory symptoms and lung function at young adult age was investigated using multiple regression models, taking other potential risk factors into account. Of 1,568 responders, 608 (39%, aged 18-22 yrs) had at least one respiratory symptom. The young adults who had a mother that smoked during pregnancy had a significantly lower level of lung function than their nonintra-uterine exposed peers (regression coefficient (B) (standard error): peak expiratory flow (PEF) -0.257 (0.131) L x s(-1); forced expiratory flow when 25% of the forced vital capacity has been exhaled (FEF25) -0.290 (0.129) L x s(-1)), although they were not at increased risk of having respiratory symptoms. Young adults who were first-born had better levels of lung function (B (SE): forced expiratory volume in one second (FEV1) 0.090 (0.042) L) and were less likely to have asthmatic symptoms (odds ratio (95%, confidence interval): 0.58 (0.35-0.95)) than those not first-born. Low birth weight (FEV1 -0.013 (0.004) L for a reduction of 100 g) was also predictive of reduced achieved levels of lung function at young adult age, independent of other potential risk factors, e.g. current smoking habits or familial predisposition. This study adds to the knowledge of the role of perinatal factors, such as smoking during pregnancy, as important predictors of respiratory morbidity.

Acute effects of particulate air pollution on respiratory admissions: results from APHEA 2 project. Air Pollution and Health: a European Approach

The APHEA 2 project investigated short-term health effects of particles in eight European cities. In each city associations between particles with an aerodynamic diameter of less than 10 microm (PM(10)) and black smoke and daily counts of emergency hospital admissions for asthma (0-14 and 15-64 yr), chronic obstructive pulmonary disease (COPD), and all-respiratory disease (65+ yr) controlling for environmental factors and temporal patterns were investigated. Summary PM(10) effect estimates (percentage change in mean number of daily admissions per 10 microg/m(3) increase) were asthma (0-14 yr) 1.2% (95% CI: 0.2, 2.3), asthma (15-64 yr) 1.1% (0.3, 1.8), and COPD plus asthma and all-respiratory (65+ yr) 1.0% (0.4, 1.5) and 0.9% (0.6, 1.3). The combined estimates for Black Smoke tended to be smaller and less precisely estimated than for PM(10). Variability in the sizes of the PM(10) effect estimates between cities was also investigated. In the 65+ groups PM(10) estimates were positively associated with annual mean concentrations of ozone in the cities. For asthma admissions (0-14 yr) a number of city-specific factors, including smoking prevalence, explained some of their variability. This study confirms that particle concentrations in European cities are positively associated with increased numbers of admissions for respiratory diseases and that some of the variation in PM(10) effect estimates between cities can be explained by city characteristics.

Risk factors for growth and decline of lung function in asthmatic individuals up to age 42 years. A 30-year follow-up study

Little is known about factors determining the outcome of childhood asthma. The purpose of this longitudinal study was to assess the factors in childhood that determine the level of FEV(1) in early adulthood in asthmatic individuals, and to examine factors associated with decline in FEV(1) during adulthood. Between 1966 and 1969, 119 allergic asthmatic subjects aged 5 to 14 yr were studied (Visit 1). Of these subjects, 101 (85%) were reinvestigated at ages 22 to 32 yr (Visit 2) and 32 to 42 yr (Visit 3). At the first survey and during follow-up, a standardized questionnaire was used, serum total IgE and peripheral blood eosinophils were measured, and physical examination, skin tests, lung function tests, and histamine challenge (provocative concentration causing a 10% decline in FEV(1); PC(10)) tests were performed according to the same protocol. Multiple linear regression analyses were performed with FEV(1) at Visit 2 and with the change of FEV(1) from Visit 2 to Visit 3 as outcome variables. A low FEV(1)% predicted at Visit 1 and PC(10) </= 16 mg/ml at Visit 1 were significantly associated with a lower level of FEV(1) at Visit 2. Subjects who quit smoking and subjects who continued to use inhaled corticosteroids had a significantly smaller annual decline in FEV(1) from Visit 2 to Visit 3, adjusted for attained level of FEV(1) at Visit 2. In conclusion, bronchial hyperresponsiveness and a low level of lung function in childhood are independent risk factors for a low level of FEV(1) in early adulthood. A smaller decline in FEV(1) after ages 22 to 32 yr occurs in asthmatics who quit smoking and who continue to use inhaled corticosteroids. Our data stress the importance of studying intervention strategies for asthma in young childhood and early adulthood in order to prevent or postpone further lung function deficits.

Smoking and airway hyperresponsiveness especially in the presence of blood eosinophilia increase the risk to develop respiratory symptoms: a 25-year follow-up study in the general adult population

Airway hyperresponsiveness (AHR) constitutes a risk for development of respiratory symptoms. We assessed whether blood eosinophilia (>/= 275 eosinophils/microliters), skin test positivity (sum score >/= 3) and cigarette smoking (never, ex-smoker, 1-14 cig/d, 15-24 cig/d, >/= 25 cig/d) at the first of two successive surveys are related to the development of respiratory symptoms (chronic cough or phlegm, bronchitis, persistent wheeze, dyspnea, and asthma) at the second survey, and whether these relations are the same in subjects with (PC10 </= 8 mg/ml histamine) and without AHR. We analyzed data of the longitudinal Vlagtwedde-Vlaardingen Study (1965 to 1990) using logistic regression analyses with paired observations, taking multiple measurements within a person into account. In total, 995 men and 792 women contributed 4,403 paired observations. Eosinophilia in hyperresponsive subjects significantly increased the risk to develop one or more respiratory symptoms (odds ratio [OR] = 3.67, 95% confidence interval [CI] = 1.79 to 7.52), wheeze (OR = 5. 06, 95% CI = 2.11 to 12.13), and dyspnea (OR = 2.73, 95% CI = 1.13 to 6.60), independent of smoking, age, sex, area of residence, and time between two successive surveys. Smoking at the first of two successive surveys increased the risk to develop symptoms in a dose-dependent relation. Subjects with positive skin tests in the past were less likely to develop one or more respiratory symptoms (OR = 0.64, 95% CI = 0.46 to 0.88) and chronic phlegm (OR = 0.65, 95% CI = 0.42 to 1.00), independent of AHR. This longitudinal study in the general adult population shows that cigarette smoking and hyperresponsive subjects are at increased risk to develop respiratory symptoms, and especially so when eosinophilia is present in hyperresponsive persons.

Risk factors from childhood to adulthood for bronchial responsiveness at age 32-42 yr

Bronchial responsiveness (BR) is an important risk factor for the development and outcome of asthma. This study assessed childhood risk factors for both the severity of BR in adulthood and either improvement or worsening of BR over time. Finally, we studied cross-sectional risk factors of BR in adulthood. Between 1966 and 1969, 119 allergic asthmatic children (5-14 yr of age) were studied. Of these, 101 (85%) subjects were reinvestigated at age 22-32 yr (visit 2), and at age 32-42 yr (visit 3). Spirometry, PC10 histamine, skin tests, blood eosinophils, and serum total IgE were measured and a questionnaire was used. Higher FEV1 values in childhood were associated with less severe BR at age 32-42 yr independent of other potential risk factors. Larger increases in FEV1 values both from visit 1 to 2 and from visit 2 to 3, a longer time interval from visit 1 to 3, and having pets in childhood were associated with less severe BR at age 32-42 yr. The same factors were found to be associated with less deterioration of BR from visit 2 to 3. In nonsmokers a higher IgE level at visit 2 was a risk factor for an increase in BR. At age 32-42 yr, a low level of lung function and the presence of asthma symptoms were associated with more severe BR, and older age and having pets were associated with less severe BR. IgE was related to more severe BR only in nonsmokers.

CONCLUSIONS

A lower lung function in childhood and less improvement in FEV1 over time were associated with more severe BR in adulthood.

Effects of ambient air pollution on upper and lower respiratory symptoms and peak expiratory flow in children

BACKGROUND

Previous epidemiological studies have shown acute effects of increased amounts of ambient air pollution on the prevalence of respiratory symptoms in children with respiratory disorders. We investigated whether children with bronchial hyperresponsiveness (BHR) and relatively high serum concentrations of total IgE (>60 kU/L, the median value) are susceptible to air pollution.

METHODS

We collected data from children during three winters (1992-95) in rural and urban areas of the Netherlands. Lower respiratory symptoms (wheeze, attacks of wheezing, shortness of breath), upper respiratory symptoms (sore throat, runny or blocked nose), and peak expiratory flow were recorded daily for 3 months. The acute effects of airborne particulate matter with a diameter of less than 10 microm, black smoke, sulphur dioxide, and nitrogen dioxide were estimated by logistic regression.

FINDINGS

459 (73%) of 632 children had complete data. Of these, 26% had BHR and relatively high (above median) serum total IgE, 36% had no BHR and total IgE of 60 kU/L or less, 15% had BHR and total IgE of 60 kU/L or less, and 23% had a total IgE of more than 60 kU/L but no BHR. In children with BHR and relatively high serum total IgE the prevalence of lower respiratory symptoms increased significantly by between 32% and 139% for each 100 microm/m3 increase in particulate matter, and between 16% and 131% for each 40 microm/m3 increase in black smoke, SO2, or NO2. Decrease in peak expiratory flow of more than 10% in that group was more common with increased airborne particulate matter and black smoke. There were no consistent positive or negative associations between increased air pollution and prevalence of respiratory symptoms or decrease in peak expiratory flow in the other three groups of children.

INTERPRETATION

Children with BHR and relatively high concentrations of serum total IgE are susceptible to air pollution. Although our odds ratios were rather low (range 1.16-2.39) the overall effect of air pollution on public health is likely to be substantial since these odds ratios refer to large numbers of people.

The importance of serum IgE for level and longitudinal change in airways hyperresponsiveness in COPD

BACKGROUND

Airways hyperresponsiveness (AHR) is an important feature of patients with chronic obstructive pulmonary disease (COPD). Little is known about factors that modulate AHR in COPD.

OBJECTIVE

To study these factors, we performed a long-term, double-blind, parallel intervention study in 58 male, non-allergic patients with COPD.

METHODS

During a period of 2 years, patients were treated with inhaled budesonide (1600 microg/day), inhaled budesonide (1600 microg/day) plus oral prednisolone (5 mg/day), or placebo. PC20 histamine was measured at 4-monthly intervals. The influence of treatment, smoking, age, level of lung function, initial serum IgE level and peripheral blood eosinophils on level and longitudinal change of PC20 histamine was analysed.

RESULTS

During follow-up, PC20 decreased in our group, and this decrease was not influenced by treatment. PC20 tended to decrease faster in current smokers than in ex-smokers. PC20 was significantly associated with pre-challenge FEV1 at each time point. Level nor decline of PC20 were significantly related to age. A higher initial serum IgE level was independently associated with a lower PC20. Moreover, a higher initial serum IgE level was associated with a slower annual decline of PC20, regardless of treatment, pre-challenge FEV1, and other modulating factors. No significant associations were found between initial blood eosinophils and level or decline of PC20.

CONCLUSION

We conclude that AHR increases over time in non-allergic patients with COPD. Treatment with an inhaled corticosteroid alone or in combination with oral prednisolone does not change this increase. Our study suggests an important role for IgE in the course of the disease, since a higher initial serum IgE level predicts a more favourable course with regard to annual decline of PC20 histamine.

Intrauterine position, parenting, and nest-site attachment in male Mongolian gerbils

We housed male Mongolian gerbils, their mates, and foster litters of standardized size and sex ratio in enclosures that provided cover in two locations. Males had been gestated in known intrauterine positions: either between two females (2F males) or between two males (2M males). From Days 1 to 20 postpartum, we examined the frequency with which both males and females were in contact with the pups they were rearing. We found that 2F males spent more time with pups than did 2M males both during entire observation periods and when females were away from the nest. Further, when pups were moved from the nest site. 2M males spent more time than did 2F males in the vacated nest site. We concluded that 2F male gerbils spent more time with pups than 2M males not because of a greater attachment of 2F than 2M males to places of concealment, their male, or their nest site. Rather, 2F males were more attracted to pups than were 2M males.

Short-term effects of air pollution on hospital admissions of respiratory diseases in Europe: a quantitative summary of APHEA study results. Air Pollution and Health: a European Approach

The Air Pollution and Health: a European Approach (APHEA) project is a coordinated study of the short-term effects of air pollution on mortality and hospital admissions. Five West European cities (i.e., London, Amsterdam, Rotterdam, Paris, Milano) contributed several years of hospital admissions data for all respiratory causes. In the current study, the authors describe the results obtained from the quantitative pooling (meta-analysis) of local analyses. The diagnostic group was defined by ICD 460-519. The age groups studied were 15-64 y (i.e., adults) and 65+ y (elderly). The air pollutants studied were sulfur dioxide; particles (i.e., Black Smoke or total suspended particles); ozone; and nitrogen dioxide. The pollutants were obtained from existing fixed-site monitors in a standardized manner. We used Poisson models and standardized confounder models to examine the associations between daily hospital admissions and air pollution. We conducted quantitative pooling by calculating the weighted means of local regression coefficients. We used a fixed-effects model when no heterogeneity could be detected; otherwise, we used a random-effects model. When possible, the authors investigated the factors correlated with heterogeneity. The most consistent and strong finding was a significant increase of daily admissions for respiratory diseases (adults and elderly) with elevated levels of ozone. This finding was stronger in the elderly, had a rather immediate effect (same or next day), and was homogeneous over cities. The elderly were affected more during the warm season. The Sulfur dioxide daily mean was available in all cities, and it was not associated consistently with an adverse effect. Effects were present in areas in which more than one station was used in the assessment of daily exposure. Some significant associations were observed, although no conclusion that related to an overall particle effect could be drawn. The effect of Black Smoke was significantly stronger with high nitrogen dioxide levels on the same day, but nitrogen dioxide itself was not associated with admissions. The ozone results were in good agreement with the results of similar U.S. studies. The coherence of the results of this study and other results gained under different conditions strengthens the argument for causality.

Short-term effects of ambient oxidant exposure on mortality: a combined analysis within the APHEA project. Air Pollution and Health: a European Approach

The Air Pollution and Health: a European Approach (APHEA) project is a coordinated study of the short-term effects of air pollution on mortality and hospital admissions using data from 15 European cities, with a wide range of geographic, sociodemographic, climatic, and air quality patterns. The objective of this paper is to summarize the results of the short-term effects of ambient oxidants on daily deaths from all causes (excluding accidents). Within the APHEA project, six cities spanning Central and Western Europe provided data on daily deaths and NO2 and/or O3 levels. The data were analyzed by each center separately following a standardized methodology to ensure comparability of results. Poisson autoregressive models allowing for overdispersion were fitted. Fixed effects models were used to pool the individual regression coefficients when there was no evidence of heterogeneity among the cities and random effects models otherwise. Factors possibly correlated with heterogeneity were also investigated. Significant positive associations were found between daily deaths and both NO2 and O3. Increases of 50 micrograms/m3 in NO2 (1-hour maximum) or O3 (1-hour maximum) were associated with a 1.3% (95% confidence interval 0.9-1.8) and 2.9% (95% confidence interval 1.0-4.9) increase in the daily number of deaths, respectively. Stratified analysis of NO2 effects by low and high levels of black smoke or O3 showed no significant evidence for an interaction within each city. However, there was a tendency for larger effects of NO2 in cities with higher levels of black smoke. The pooled estimate for the O3 effect was only slightly reduced, whereas the one for NO2 was almost halved (although it remained significant) when two pollutant models including black smoke were applied. The internal validity (consistency across cities) as well as the external validity (similarities with other published studies) of our results on the O3 effect support the hypothesis of a causal relation between O3 and all cause daily mortality. However, the short-term effects of NO2 on mortality may be confounded by other vehicle-derived pollutants. Thus, the issue of independent NO2 effects requires additional investigation.

Adult patients may outgrow their asthma: a 25-year follow-up study

The present study investigated the outcome of asthma in a population of 181 adult patients 13 to 44 yr of age (median, 24 yr) who were extensively tested between 1962 and 1970 and in whom asthma was diagnosed. When retested 25 yr later, 38 subjects (21%) did not show bronchial hyperresponsiveness (BHR)(PC20 > 16 mg/ml), 45 subjects (25%) showed a FEV1 > 90% predicted, and 72 subjects (40%) did not report pulmonary symptoms. When absence of asthma was defined as no BHR, FEV1 > 90% predicted, and the absence of pulmonary symptoms reported by the patient, 20 subjects (11%) were no longer considered asthmatic when retested. Absence of asthma after 25 yr was associated with a younger age and less severe airway obstruction at first testing, odds ratios (OR) being 0.36 for age/10 yr, and 1.42 for FEV1/height2 (dl/m2). Absence of BHR was associated with a younger age, a higher FEV1, and a shorter untreated period (years between onset of asthma symptoms and specialized treatment of the disease) at first testing, and a lower total serum IgE level (IU/L) at second testing (OR, 0.48 for age/10 yr; OR, 1.37 for FEV1/height2; OR, 0.93 for untreated period; OR, 0.33 for log [IgE]). Neither sex nor atopy (one or more positive skin tests) were significant determinants of the outcome of both asthma and BHR. Our results suggest that in a substantial proportion of symptomatic asthmatics the disease improved, and that subsets may outgrow their asthma, even in adulthood. The data lend indirect support to the hypothesis that milder disease and earlier intervention are important for a beneficial outcome of asthma.

Reproductive profiles of adult Mongolian gerbils gestated as the sole fetus in a uterine horn

We compared reproductive profiles of Mongolian gerbils gestated alone in a uterine horn (Isolate males and Isolate females) with those of gerbils gestated in intrauterine positions between two male fetuses (2M males and 2M females) and two female fetuses (2F males and 2F females). We found that, when adult, the reproductive profiles of gerbils that had been gestated as isolates resembled that of gerbils that had been gestated as 2F fetuses: 1. Isolate females gestated litters containing both the same proportion of males as the litters of 2F females and a significantly smaller proportion of males than litters of 2M females. 2. Isolate males, like 2F males, were less likely to impregnate females than were 2M males, and 3. both 2F males and isolate males exhibited disturbed patterns of copulation and reduced levels of scent-marking relative to 2M males. Our results were entirely consistent with the view that intrauterine exposure to males, but not to females, was responsible for previously described differences in the reproductive profiles of 2M and 2F Mongolian gerbils.

Short term effects of air pollution on emergency hospital admissions for respiratory disease: results of the APHEA project in two major cities in The Netherlands, 1977-89

STUDY OBJECTIVE

To assess the short term relationship between air pollution and the daily number of emergency hospital admissions for respiratory disease.

DESIGN

Data were analysed using autoregressive Poisson regression allowing for overdispersion and controlling for possible confounding factors such as seasonal and other chronological variables, meteorological factors, and influenza epidemics.

SETTING

The two major cities in The Netherlands-Amsterdam (694,700 inhabitants) and Rotterdam (576,200 inhabitants).

PARTICIPANTS AND MEASUREMENTS

Emergency hospital admissions for respiratory diseases, registered on a daily basis by the National Medical Registration, for the period 1977-89 were used. ICD-9 codes included were: respiratory (460-519), chronic obstructive pulmonary disease (490-492, 494, 496), and asthma (493). The mean (range) of the total daily number of admissions for these three classifications were as follows: 6.70 (0-23), 1.74 (0-9) and 1.13 (0-7) respectively in Amsterdam and 4.79 (0-19), 1.57 (0-9), and 0.53 (0-5) in Rotterdam. Air pollution measurements were provided by the National Institute of Public Health and Environmental Protection. In The Netherlands, air pollution is at a low to moderate ("summer type") or a low ("winter type") level. The levels in Amsterdam and Rotterdam did not differ much for the "summer type". For 1977-89 the mean (range) values of ozone (O3), the "summer type" pollutant (O3-8 h), were 86 (0-252) micrograms/m3 in Amsterdam and 82 (0-286) micrograms/m3 in Rotterdam. The mean (range) of the values "winter type", pollutant, sulphur dioxide (SO2-24 h), were 38 (0-381) micrograms/m3 in Amsterdam and 50 (1-379) micrograms/m3 in Rotterdam. For black smoke (BS-24 h), values were 14 (1-84) micrograms/m3 and 28 (1-144) micrograms/m3 respectively (1986-89).

MAIN RESULTS

Ozone had a non-significant positive effect on the number of respiratory emergency admissions in summer in people aged > or = 65 years (relative risk for a 100 micrograms/m3 increase in O3-8 h of 1.127 (0.983, 1.292) in Amsterdam and a significant positive effect of 1.344 (1.097, 1.647) in 1977-81 in Rotterdam). Sulphur dioxide did not show any clear effects; in Amsterdam a significant negative effect was even found. The same was true for nitrogen dioxide in Amsterdam; in Rotterdam, however, nitrogen dioxide showed non-significant positive effects (RR 0.965, 1.342). Black smoke did not show any clear effects in Amsterdam; in Rotterdam it was positively but not significantly related to the number of admissions.

CONCLUSIONS

The results show that the relation between short term air pollution and emergency hospital admissions is not always consistent at these rather low levels of daily hospital admissions and of air pollution.

Short term effects of air pollution on health: a European approach using epidemiologic time series data: the APHEA protocol

BACKGROUND AND OBJECTIVES

Results from several studies over the past five years have shown that the current levels of pollutants in Europe and North America have adverse short term effects on health. The APHEA project aims to quantifying these in Europe, using standardised methodology. The project protocol and analytical methodology are presented here.

DESIGN

Daily time series data were gathered for several air pollutants (sulphur dioxide; particulate matter, measured as total particles or as the particle fraction with an aerodynamic diameter smaller than a certain cut off, or as black smoke; nitrogen dioxide; and ozone) and health outcomes (the total and cause specific number of deaths and emergency hospital admissions). The data included fulfilled the quality criteria set by the APHEA protocol.

SETTING

Fifteen European cities from 10 different countries with a total population over 25 million.

METHODOLOGY

The APHEA collaborative group decided on a specific methodological procedure to control for confounding effects and evaluate the hypothesis. At the same time there was sufficient flexibility to allow local characteristics to be taken into account. The procedure included modelling of all potential confounding factors (that is, seasonal and long term patterns, meteorological factors, day of the week, holidays, and other unusual events), choosing the "best" air pollution models, and applying diagnostic tools to check the adequacy of the models. The final analysis used autoregressive Poisson models allowing for overdispersion. Effects were reported as relative risks contrasting defined increases in the corresponding pollutant levels. Each participating group applied the analyses to their own data.

CONCLUSIONS

This methodology enabled results from many different European settings to be considered collectively. It represented the best available compromise between feasibility, comparability, and local adaptibility when using aggregated time series data not originally collected for the purpose of epidemiological studies.