Agreement between spirometry and tracheal auscultation in assessing bronchial responsiveness in asthmatic children

We have recently found that changes in lung sounds correspond well with a 20% fall in the forced expiratory volume in 1 s (FEV1) after methacholine challenge in asthmatic children. Up to now, little was known about the agreement between a 20% fall in FEV1 and a change in lung sounds after repeated bronchial challenge. In this study we investigated the agreement between the total cumulative histamine dose causing a fall in FEV1 of 20% or more (PD20) and the detection of a change in lung sounds (PDlung sounds) after two bronchial challenges on different occasions in asthmatic children. Fifteen asthmatic children (nine boys), mean age 10.8 years (range 9-15), were studied. All performed two histamine challenge tests on 2 days, with a 24 h to 1 week interval. Lung sounds were recorded over the trachea for 1 min and stored on tape. Lung sounds were analysed directly and also scored from the tape-recording by a blinded second investigator. Wheeze, cough, and an increase in respiratory rate were assessed. The relationship between PD20 and PDlung sounds was calculated by Bland and Altman's measurement of agreement. Eleven children had a positive challenge test (PD20 < or = 16.0 mg ml-1) on both test days; four had a positive challenge on one test day. In 24 out of 26 positive challenges, wheeze, cough, prolonged expiration and/or increased respiratory rate were detected one dose-step before, or at the dose-step of histamine that induced a fall in FEV1 of 20% or more. In two challenges, PD20 was not detected by a change in lung sounds. In four out of four negative challenges (PD20 > 16.0 mg ml-1) no change in lung sounds could be detected. Good agreement between the logarithm of PD20 and the logarithm of PDlung sounds was found on both test days. The mean difference was 0.04 and the limits of agreement (d +/- 2 SD of the differences) were 0.04 +/- 0.41. A good agreement was found between the total cumulative histamine dose causing a fall in FEV1 of 20% or more and the detection of a change in lung sounds after two bronchial challenges on different occasions in asthmatic children.

Breathlessness in elderly individuals is related to low lung function and reversibility of airway obstruction

The perception of breathlessness is a subject-related factor which is linked to respiratory disease, cardiac disease and overweight. We studied the distribution of breathlessness, its association with respiratory disease, cardiac disease and overweight, as well as its association with lung function, reversibility of airway obstruction ("reversibility") and peak expiratory flow (PEF) variability in an elderly population. Data on breathlessness (rated with Borg scale), lung function, reversibility, PEF variability, respiratory symptoms, cardiac disease and overweight were collected in a random sample of 210 elderly (>55 yrs old) who participated in a physical fitness test. Individuals with a Borg score >0 were taken to have breathlessness. Subjects with a Borg score >0 (n=50, 24%) were three to five times more likely to have a low lung function and large reversibility than subjects with a Borg score of zero, independent of the presence of respiratory symptoms, cardiac disease or overweight, although these three factors were all associated with low lung function and a large reversibility and PEF variability. Reversibility was not associated with PEF variability whatsoever. In elderly individuals, breathlessness is frequently present. Assessment of breathlessness using the Borg-scale seems an important clinical measurement, because it is an important independent predictor of lung function impairment in the elderly.

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.

Lack of correlation between bronchoconstrictor response and bronchodilator response in a population-based study

Bronchodilator and bronchoconstrictor responsiveness have been considered physiological opposites in patients with obstructive airways disease. Provocation challenges have been replaced by bronchodilator tests in the assessment of cases of severe airways obstruction. The aim of this study was to examine the relationship between bronchoconstrictor and bronchodilator responsiveness, and their supposed interchangeability, in a general population. From the Vlagtwedde-Vlaardingen follow-up study, 101 adults were recruited (mean (SD) age 55 (11) yrs, 67 males and 34 females, and 31 were smokers). All completed a questionnaire on airways symptoms. Bronchoconstrictor and bronchodilator responsiveness were assessed with cumulative dose-response curves, using histamine and terbutaline, respectively. Thus, it was possible to relate histamine sensitivity of the airways (the concentration of histamine, at which forced expiratory volume in one second (FEV1) falls by 10% (PC10)) to the maximal bronchodilator response (delta FEV1) and the sensitivity to the bronchodilator (cumulative dose of inhaled terbutaline at which FEV1 increases by 10% (RD10)). Subjects with a bronchoconstrictor response (PC10 < or = 16 mg x mL(-1); n=38) had more respiratory symptoms than those without (n=63) (40 versus 21%) and also lower baseline FEV1 values (90 versus 96% predicted), but had comparable bronchodilator responsiveness. Subjects with a bronchodilator response (delta FEV1 > or = 9% of the predicted value; n=13) did not differ from those without (n=88) for all parameters, including symptoms, allergy and pulmonary function. In those with a bronchoconstrictor response, there was a weak but significant correlation between the PC10 and RD10 (rho=-0.32), but not between PC10 and delta FEV1. This study suggests that bronchoconstrictor and bronchodilator responsiveness are not highly correlated, even in subjects with airways obstruction. Symptoms were associated with the presence of a bronchoconstrictor, but not a bronchodilator, response. We conclude that bronchoconstrictor and bronchodilator responsiveness are two different phenotypic markers that are not interchangeable in epidemiological studies.

Airways responsiveness and development and remission of chronic respiratory symptoms in adults

BACKGROUND

Many patients with chronic obstructive lung disease show increased airways responsiveness to histamine. We investigated the hypothesis that increased airways responsiveness predicts the development and remission of chronic respiratory symptoms.

METHODS

We used data from 24-year follow-up (1965-90) of 2684 participants in a cohort study in Vlagtwedde and Vlaardingen, Netherlands. Increased airways responsiveness was defined as a PC10 value (concentration of histamine for which challenge led to a 10% fall in forced expiratory volume in 1 s) of less than 8 mg/mL. Information on respiratory symptoms was collected by means of a standard questionnaire every 3 years. Logistic regression was used to control for age, area of residence, cigarette smoking status, and sex.

FINDINGS

Participants with increased airways responsiveness (1281 observations) were more likely than those without increased airways responsiveness (5801 observations) to develop the following symptoms during any 3-year follow-up interval: chronic cough (odds ratio 1.9 [95% CI 1.2-2.9]), chronic phlegm (2.0 [1.3-3.0]), dyspnoea (2.3 [1.5-3.5]), asthmatic attacks (3.7 [2.2-6.1]), and persistent wheeze (2.7 [1.7-4.4]). The estimate of the odds ratio for the development of any of the six symptoms was 1.7 (1.2-2.3). Participants with increased airways responsiveness were less likely than those without this characteristic to show remission of these respiratory symptoms. The estimate of the odds ratio for the remission of any of the six symptoms was 0.42 (0.28-0.61).

INTERPRETATION

These prospective analyses show that increased airways responsiveness is positively associated with the development of chronic respiratory symptoms and negatively associated with the remission of these symptoms in adults.

Severity scoring of atopic dermatitis: a comparison of three scoring systems

In studies on atopic dermatitis (AD), different scoring systems are used to evaluate the severity of the disease. The objective of this study was to investigate agreement between observers in the assessment of the overall severity of AD, and interobserver variation in the assessment of severity of AD for each scoring item separately, using the Simple Scoring System (SSS), the Scoring Atopic Dermatitis (SCORAD) index, and the Basic Clinical Scoring System (BCSS), and, furthermore, to investigate agreement between these three scoring systems in the assessment of the overall severity of AD. Eighty-two patients (42 male) with AD, mean age 13.4 years (range 0.2-67.0), were included. Agreement between observers in assessing the overall AD severity scores, and interobserver variation in assessing AD severity of each scoring item separately were determined in 34 of these 82 patients by two physicians scoring the severity of AD by the three scoring systems. To determine agreement between the scoring systems, one physician scored the severity of AD in all patients with the three scoring systems. Agreement between observers and agreement between the three scoring systems was calculated by Cohen's kappa (kappa) and by the measure of agreement according to Bland & Altman. kappa > 0.4 represents fair agreement; kappa > 0.75 excellent agreement. In addition, interobserver variation for each scoring item separately was calculated by the Wilcoxon signed rank test. The mean differences (d) and the limits of agreement (d +/- 2 SD of the differences) between observers by the SSS and the SCORAD were -0.82 +/- 5.58 and -0.28 +/- 7.49, respectively, kappa between observers for the BCSS was 0.90 (95% CI 0.79-1.03). By the SSS, significant interobserver variation was found in assessing the severity of excoriations (P = 0.02) and scales (P = 0.02). By the SCORAD, significant interobserver variation was found in assessing the severity of edema/population (P = 0.04), erythema (P = 0.04), and excoriations (P = 0.01). No significant interobserver variation was found in assessing the extent of AD. The mean difference and the limits of agreement between the SSS and the SCORAD were -4.17 +/- 9.52. kappa between the SSS and the BCSS was 0.21 (95% CI 0.09-0.33), and kappa between the SCORAD and the BCSS was 0.38 (95% CI 0.26-0.51). We found good agreement between observers assessing the overall severity of AD in the lower and higher scoring rates by the SSS and the SCORAD, and excellent agreement by the BCSS. Significant interobserver variation was found on the isolated intensity items scales, excoriations, edema/population, and erythema. We found poor agreement between the three scoring systems in assessing the overall severity of AD, indicating that the SSS, the SCORAD, and the BCSS cannot be used interchangeably to assess the overall severity of AD.

Short-term effects of ambient sulphur dioxide and particulate matter on mortality in 12 European cities: results from time series data from the APHEA project. Air Pollution and Health: a European Approach

OBJECTIVES

To carry out a prospective combined quantitative analysis of the associations between all cause mortality and ambient particulate matter and sulphur dioxide.

DESIGN

Analysis of time series data on daily number of deaths from all causes and concentrations of sulphur dioxide and particulate matter (measured as black smoke or particles smaller than 10 microns in diameter (PM10)) and potential confounders.

SETTING

12 European cities in the APHEA project (Air Pollution and Health: a European Approach).

MAIN OUTCOME MEASURE

Relative risk of death.

RESULTS

In western European cities it was found that an increase of 50 micrograms/m3 in sulphur dioxide or black smoke was associated with a 3% (95% confidence interval 2% to 4%) increase in daily mortality and the corresponding figure for PM10 was 2% (1% to 3%). In central eastern European cities the increase in mortality associated with a 50 micrograms/m3 change in sulphur dioxide was 0.8% (-0.1% to 2.4%) and in black smoke 0.6% (0.1% to 1.1%). Cumulative effects of prolonged (two to four days) exposure to air pollutants resulted in estimates comparable with the one day effects. The effects of both pollutants were stronger during the summer and were mutually independent.

CONCLUSIONS

The internal consistency of the results in western European cities with wide differences in climate and environmental conditions suggest that these associations may be causal. The long term health impact of these effects is uncertain, but today's relatively low levels of sulphur dioxide and particles still have detectable short term effects on health and further reductions in air pollution are advisable.

Air pollution and daily admissions for chronic obstructive pulmonary disease in 6 European cities: results from the APHEA project

We investigated the short-term effects of air pollution on hospital admissions for chronic obstructive pulmonary disease (COPD) in Europe. As part of a European project (Air Pollution and Health, a European Approach (APHEA)), we analysed data from the cities of Amsterdam, Barcelona, London, Milan, Paris and Rotterdam, using a standardized approach to data eligibility and statistical analysis. Relative risks for daily COPD admissions were obtained using Poisson regression, controlling for: seasonal and other cycles; influenza epidemics; day of the week; temperature; humidity and autocorrelation. Summary effects for each pollutant were estimated as the mean of each city's regression coefficients weighted by the inverse of the variance, allowing for additional between-cities variance, as necessary. For all ages, the relative risks (95% confidence limits (95% CL)) for a 50 microg x m(-3) increase in daily mean level of pollutant (lagged 1-3 days) were (95% CL): sulphur dioxide 1.02 (0.98, 1.06); black smoke 1.04 (1.01, 1.06); total suspended particulates 1.02 (1.00, 1.05), nitrogen dioxide 1.02 (1.00, 1.05) and ozone (8 h) 1.04 (1.02, 1.07). The results confirm that air pollution is associated with daily admissions for chronic obstructive pulmonary disease in European cities with widely varying climates. The results for particles and ozone are broadly consistent with those from North America, though the coefficients for particles are substantially smaller. Overall, the evidence points to a causal relationship but the mechanisms of action, exposure response relationships and pollutant interactions remain unclear.

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.

Distribution of total serum IgE and specific IgE to common aeroallergens by sex and age, and their relationship to each other in a random sample of the Dutch general population aged 20-70 years. Dutch ECRHS Group, European Community Respiratory Health Study

To describe the distribution of serum total IgE and specific IgE to common aeroallergens by sex and age and to study their relationship to each other, we measured serum total IgE and specific IgE (CAP) to house-dust mite, timothy grass, cat, birch, and Cladosporium in a random sample of 2496 subjects, aged 20-70 years from the Dutch general population. We found that total IgE was higher in men, independently of smoking, and that total IgE had no relationship with age after adjustment for specific IgE and smoking in linear regression analysis. At least one positive specific IgE test was found in 32% in both sexes. Men had higher prevalences of specific IgE to house-dust mite and lower prevalences of specific IgE to birch than women. The proportion with positive specific IgE decreased with age. The mean total IgE increased with the number of positive specific IgE tests. Thus, total IgE is higher in men and has no relationship with age if specific IgE is taken into account. The prevalences of specific IgE to aeroallergens are high and decrease with increasing age. We suggest that sex differences in total IgE should be considered when using total IgE.

PEF variability, bronchial responsiveness and their relation to allergy markers in a random population (20-70 yr)

We investigated the coherence of bronchial hyperresponsiveness (BHR) and peak expiratory flow (PEF) variability in their relation to allergy markers and respiratory symptoms in 399 subjects (20-70 yr). Bronchial hyperresponsiveness to methacholine was defined by both the provocative dose causing a fall in FEV1 of 20%, and the dose-response slope. PEF variability was determined as diurnal PEF variation (amplitude percent mean) and between-day PEF variation. Skin tests positivity, serum total IgE, and specific IgE (RAST) for house-dust mite (HDM), cat, timothy grass, and birch ("pollen") were determined, as well as the number of peripheral blood eosinophils. Wheeze and nocturnal dyspnea were defined as asthma-like symptoms; dyspnea > or = grade 3, cough and phlegm as chronic obstructive pulmonary disease (COPD)-like symptoms. The reciprocal of the dose-response slope and PEF variability were significantly correlated (r = -0.39). Subjects with a positive skin test for HDM (odds ratio [OR] = 3.9), cat (OR = 8.3), or pollen (OR = 3.6), or specific IgE for HDM (OR = 2.3), cat (OR = 3.4), or pollen (OR = 1.9) had increased risk of BHR compared with the reference group (all p values < 0.05). Higher levels of serum total IgE were significantly associated with higher odds for BHR (OR = 2.5 per log unit). There was no significant association between skin test positivity, serum total IgE, or presence of specific IgE and PEF variability. Neither BHR nor PEF variability were associated with higher numbers of peripheral blood eosinophils. There are different associations of BHR and PEF variability with allergy markers. Although BHR and PEF variability are significantly correlated, they cannot be used interchangeably in epidemiologic settings.

Effects of long-term treatment with corticosteroids in COPD

STUDY OBJECTIVE

To determine the effectiveness of treatment with corticosteroids in patients with COPD.

METHODS

In this study, we investigated the effect of a 2-year treatment with corticosteroids on clinical symptoms and the decline of lung function in 58 nonallergic patients with COPD. Subjects were treated in a double-blind, randomized, placebo-controlled, parallel way with inhaled budesonide (bud), 1,600 micrograms/d; inhaled budesonide, 1,600 micrograms/d, plus oral prednisolone, 5 micrograms/d (bud + pred); or placebo (plac). Clinical assessment (history, physical examination, and spirometry) was carried out every 2 months. The rate of decline in FEV1 was assessed by calculating individual regression co-efficients from linear regression of FEV1 on time for each subject.

RESULTS

Eleven patients dropped out. The number of withdrawals due to pulmonary problems was significantly higher in the plac group (n = 5 out of 18) than in the actively treated groups (n = 2 out of 40). Treatment with corticosteroids significantly reduced pulmonary symptoms. Median decline of FEV1 was 60 mL/yr in the plac group, 40 mL/yr in the bud + pred group, and 30 mL/yr in the bud group. Variation was large and differences were not statistically significant. No treatment effect was found on frequency or duration of exacerbations, possibly because of the high number of withdrawals due to pulmonary deterioration in the plac group. Treatment with a combination of inhaled plus oral corticosteroids was not more effective than inhaled corticosteroids alone. Morning plasma cortisol levels remained within the normal range in all three groups.

CONCLUSIONS

Our study shows beneficial effects of long-term daily treatment with inhaled corticosteroids in patients with COPD with regard to symptoms and drop out due to pulmonary problems. Lung function decline tends to decrease during treatment with inhaled corticosteroids. The observed effects are limited but warrant further studies on the effectiveness of corticosteroids in larger numbers of patients with COPD.

Association of skin test reactivity, specific IgE, total IgE, and eosinophils with nasal symptoms in a community-based population study. The Dutch ECRHS Group

BACKGROUND

Skin prick tests and measurement of specific IgE are important markers of the possible causes of disorders of the upper respiratory tract.

OBJECTIVE

In this study we investigated the association of skin test reactivity and specific IgE positivity to five common aeroallergens separately and of total serum IgE and eosinophil count with nasal allergy symptoms in a random sample of the adult population in the Netherlands.

METHODS

A cross-sectional study was carried out in a sample of 2167 subjects, aged 20 to 70 years, stratified by age and gender. Nasal allergy symptoms were differentiated into three categories: symptoms after exposure to indoor allergens only, symptoms after exposure to outdoor allergens only, and symptoms after exposure to both indoor and outdoor allergens. Associations were investigated by multiple logistic regression analyses with adjustment for area of residence, gender, age, and smoking status.

RESULTS

Skin test and specific IgE reactivity to indoor and outdoor allergens were significantly related to their corresponding nasal symptom groups. Odd ratios increased with increasing number of positive skin test results or increasing levels of specific IgE to allergens in all three nasal symptom groups. For each allergen, a positive skin test result together with a positive specific IgE measurement were the strongest predictors of nasal symptoms. Sensitization to house dust mite was the most prevalent in our study population, whereas the association of skin test reactivity and specific IgE positivity with nasal symptoms was strongest for cat allergen. Skin test and specific IgE reactivity to Cladosporium species were not significantly related to the prevalence of nasal symptoms. Total serum IgE was related to nasal symptoms only in subjects who reported symptoms in response to both indoor and outdoor allergens and only at high levels of IgE. Eosinophil count was associated with nasal symptoms in all nasal symptom groups.

CONCLUSION

Our findings confirm the close relationship of skin test positivity with reported symptoms of nasal allergy in a general population. Specific IgE positivity also shows a close relationship with nasal symptoms in response to allergen exposure in a general population. Skin testing and specific IgE measurement may be considered complementary to one another in diagnosing allergic rhinitis. Total IgE may be considered an indicator of greater dysregulation of the immune system in atopic allergy. Eosinophil count is associated with nasal symptoms, regardless of type and extent of nasal symptoms.

Methodological issues in studies of air pollution and daily counts of deaths or hospital admissions

STUDY OBJECTIVE

To review the issues and methodologies in epidemiologic time series studies of daily counts of mortality and hospital admissions and illustrate some of the methodologies.

DESIGN

This is a review paper with an example drawn from hospital admissions of the elderly in Cleveland, Ohio, USA.

MAIN RESULTS

The central issue is control for seasonality. Both over and under control are possible, and the use of diagnostics, including plots, is necessary. Weather dependence is probably non-linear, and adequate methods are necessary to adjust for this. In Cleveland, the use of categorical variables for weather and sinusoidal terms for filtering season are illustrated. After control for season, weather, and day of the week effects, hospital admission of persons aged 65 and older in Cleveland for respiratory illness was associated with ozone (RR = 1.09, 95% CI 1.02, 1.16) and particulates (PM10 (RR = 1.12, 95% CI 1.01, 1.24), and marginally associated with sulphur dioxide (SO2) (RR = 1.03, 95% CI = 0.99, 1.06). All of the relative risks are for a 100 micrograms/m3 increase in the pollutant.

CONCLUSIONS

Several adequate methods exist to control for weather and seasonality while examining the associations between air pollution and daily counts of mortality and morbidity. In each case, care and judgement are required.

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.

Comparing FEV1 in adults in two community-based studies

Data collected in two large-scale longitudinal respiratory studies were analyzed to estimate age-related changes in FEV1 and to determine the between-study differences in change in FEV1 among nonsmoking participants. Two adult cohorts in the Netherlands were followed up for 21 years at 3-year intervals and a cohort of adults in 6 cities in the eastern United States was followed up for 6 years. The age distributions and follow-up rate differed for the two studies. The mean rates of decline in FEV1 for 50-year old male and female never smokers were 27.9 +/- 2.8 mL/yr and 22.1 +/- 0.9 mL/yr, respectively, in the Netherlands cohort. The estimates for men and women in the Six Cities cohort were 33% and 32% greater, respectively, than those for the Netherlands cohort (p < 0.01). The estimated rate of decline in FEV1 associated with each 1-year increase in age was 0.50 +/- 0.12 mL/yr for men and 0.61 +/- 0.08 mL/yr for women in the Netherlands cohort. This estimate was comparable for the Six Cities women and the Netherlands women but significantly different for the two cohorts of men. Inclusion of survey (period) effect in the regression model had only a trivial influence on accelerated rate of decline in FEV1 and did not alter the more rapid acceleration of decline in FEV1 among the Six Cities men. The present study also showed that use of a "prediction equation" for age adjustment to compare across population samples may produce a biased conclusion if the estimated rate of decline in FEV1 associated with age is different and the age distributions are different for the two populations. In addition, height adjustment for FEV1 was found to have a negligible influence on the longitudinal estimates of FEV1 decline in both study samples. In conclusion, substantial between study variation in decline in FEV1 occurs despite use of similar data analysis techniques. Differences in the initial age distributions and loss to follow-up appeared to be important factors in this analysis.

Short-term effects of air pollution on health: a European approach using epidemiological time-series data. The APHEA project: background, objectives, design

Recent studies investigating the adverse health effects of air pollution indicate that effects exist around and below the current national and international air quality guidelines and standards. However, the difficult methodological issues involved, and the diversity of analytical techniques so far applied, hinder direct between-study comparability and the drawing of clear conclusions. The APHEA (Air Pollution on Health: European Approach) project is an attempt to provide quantitative estimates of the short-term health effects of air pollution, using an extensive data base from 10 different European countries, which represent various social, environmental and air pollution situations. Within the framework of the project, the methodology of analysing epidemiological time series data, as well as that of performing meta-analysis, are further developed and standardized. Data have been collected from 15 European cities with a total population exceeding 25 million. The exposure data consist of daily measurements of black smoke, sulphur dioxide, suspended particles, nitrogen dioxide and ozone (each available in several, though not all, cities) from already existing monitoring networks. There is substantial variability in air pollution mixtures and air pollutant levels in participating cities. The mean (24 h) levels of SO2 range 27-327 micrograms.m-3 in the winter season, and those of black smoke range 15-292 micrograms.m-3. The mean (1 h) levels of ozone in the summer season range 32-166 micrograms.m-3. The outcome data are daily counts of total and cause-specific deaths and hospital emergency admissions. Data on potential confounders (mainly meteorological and chronological variables) are also used. There is large diversity in the climatic conditions in the different cities.(ABSTRACT TRUNCATED AT 250 WORDS)

Short-term effects of air pollution on health: a European approach using epidemiological time-series data. The APHEA project: background, objectives, design

Recent studies investigating the adverse health effects of air pollution indicate that effects exist around and below the current national and international air quality guidelines and standards. However, the difficult methodological issues involved, and the diversity of analytical techniques so far applied, hinder direct between-study comparability and the drawing of clear conclusions. The APHEA (Air Pollution on Health: European Approach) project is an attempt to provide quantitative estimates of the short-term health effects of air pollution, using an extensive data base from 10 different European countries, which represent various social, environmental and air pollution situations. Within the framework of the project, the methodology of analysing epidemiological time series data, as well as that of performing meta-analysis, are further developed and standardized. Data have been collected from 15 European cities with a total population exceeding 25 million. The exposure data consist of daily measurements of black smoke, sulphur dioxide, suspended particles, nitrogen dioxide and ozone (each available in several, though not all, cities) from already existing monitoring networks. There is substantial variability in air pollution mixtures and air pollutant levels in participating cities. The mean (24 h) levels of SO2 range 27-327 micrograms.m-3 in the winter season, and those of black smoke range 15-292 micrograms.m-3. The mean (1 h) levels of ozone in the summer season range 32-166 micrograms.m-3. The outcome data are daily counts of total and cause-specific deaths and hospital emergency admissions. Data on potential confounders (mainly meteorological and chronological variables) are also used. There is large diversity in the climatic conditions in the different cities.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway hyperresponsiveness to histamine associated with accelerated decline in FEV1

An increased level of airway responsiveness has been proposed as a risk factor associated with the onset and prognosis of chronic airway obstruction. To determine this, longitudinal studies are necessary, with measurement of both the level of airway responsiveness and of additional risk factors, such as cigarette smoking, made before measurement of pulmonary function decline. The association of airways responsiveness with decline in FEV1 has been prospectively studied in a random sample of the Dutch population. Longitudinal data from 921 males, providing 2,376 paired observations, and 698 females, providing 1,682 paired observations, were used for analysis. Differences between responders and nonresponders (PC10 < or = 16 mg/ml of histamine) were estimated from linear regression analyses stratified by gender and smoking status, with adjustment for age, residential area, the presence of respiratory symptoms, indicators for each interval, and residuals of FEV1 at the beginning of the interval. Responders had a greater mean yearly decline in FEV1, and the differences between responders and nonresponders were similar for all gender and smoking subgroups. In an overall regression model, subjects with airway hyperresponsiveness had a significantly steeper decline in FEV1, independent of the other variables (males: beta = -12.5 ml/yr, SEM = 3.22, p < 0.001; females: beta = -11.50 ml/yr, SEM = 2.98, p < 0.001). The current analyses conclusively demonstrated that increased airway responsiveness is an independent risk factor for an accelerated decline in FEV1 and, hence, for the development of chronic obstructive lung disease. The mechanisms by which increased airway responsiveness leads to an accelerated decline in FEV, are imperfectly understood and require further study.