Nino Künzli

The Global Burden of Disease Due to Outdoor Air Pollution

As part of the World Health Organization (WHO) Global Burden of Disease Comparative Risk Assessment, the burden of disease attributable to urban ambient air pollution was estimated in terms of deaths and disability-adjusted life years (DALYs). Air pollution is associated with a broad spectrum of acute and chronic health effects, the nature of which may vary with the pollutant constituents. Particulate air pollution is consistently and independently related to the most serious effects, including lung cancer and other cardiopulmonary mortality. The analyses on which this report is based estimate that ambient air pollution, in terms of fine particulate air pollution (PM2.5), causes about 3% of mortality from cardiopulmonary disease, about 5% of mortality from cancer of the trachea, bronchus, and lung, and about 1% of mortality from acute respiratory infections in children under 5 yr, worldwide. This amounts to about 0.8 million (1.2%) premature deaths and 6.4 million (0.5%) years of life lost (YLL). This burden occurs predominantly in developing countries; 65% in Asia alone. These estimates consider only the impact of air pollution on mortality (i.e., years of life lost) and not morbidity (i.e., years lived with disability), due to limitations in the epidemiologic database. If air pollution multiplies both incidence and mortality to the same extent (i.e., the same relative risk), then the DALYs for cardiopulmonary disease increase by 20% worldwide.

Indoor time-microenvironment-activity patterns in seven regions of Europe

Personal exposure to environmental substances is largely determined by time–microenvironment–activity patterns while moving across locations or microenvironments. Therefore, time–microenvironment–activity data are particularly useful in modeling exposure. We investigated determinants of workday time–microenvironment–activity patterns of the adult urban population in seven European cities. The EXPOLIS study assessed workday time–microenvironment–activity patterns among a total of 1427 subjects (age 19–60 years) in Helsinki (Finland), Athens (Greece), Basel (Switzerland), Grenoble (France), Milan (Italy), Prague (Czech Republic), and Oxford (UK). Subjects completed time–microenvironment–activity diaries during two working days. We present time spent indoors — at home, at work, and elsewhere, and time exposed to tobacco smoke indoors for all cities. The contribution of sociodemographic factors has been assessed using regression models. More than 90% of the variance in indoor time–microenvironment–activity patterns originated from differences between and within subjects rather than between cities. The most common factors that were associated with indoor time–microenvironment–activity patterns, with similar contributions in all cities, were the specific work status, employment status, whether the participants were living alone, and whether the participants had children at home. Gender and season were associated with indoor time–microenvironment–activity patterns as well but the effects were rather heterogeneous across the seven cities. Exposure to second-hand tobacco smoke differed substantially across these cities. The heterogeneity of these factors across cities may reflect city-specific characteristics but selection biases in the sampled local populations may also explain part of the findings. Determinants of time–microenvironment–activity patterns need to be taken into account in exposure assessment, epidemiological analyses, exposure simulations, as well as in the development of preventive strategies that focus on time–microenvironment–activity patterns that ultimately determine exposures.

Follow-up of the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA 2) 1991–2003: methods and characterization of participants

Summary.Objectives: The Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) was designed to investigate the health effects from long-term exposure to air pollution.Methods: The health assessment at recruitment (1991) and at the first reassessment (2001–3) consisted of an interview about respiratory health, occupational and other exposures, spirometry, a methacholine bronchial challenge test, end-expiratory carbon monoxide (CO) measurement and measurement for atopy. A bio bank for DNA and blood markers was established. Heart rate variability was measured using a 24-hour ECG (Holter) in a random sample of participants aged 50xa0years and older. Concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3) and particulates in ambient air have been monitored in all study areas since 1991. Residential histories collected over the 11xa0year follow-up period coupled with GIS modelling will provide individual long-term air pollutant exposure estimates.Results: Of 9651 participants examined in 1991, 8715 could be traced for the cohort study and 283 died. Basic information about health status was obtained for 8047 individuals (86% of alive persons), 6528 individuals (70%) agreed to the health examination and 5973 subjects (62%) completed the entire protocol. Non-participants in the reassessment were on average younger than participants and more likely to have been smokers and to have reported respiratory symptoms in the first assessment. Average weight had increased by 5.5xa0kg in 11xa0years and 28% of smokers in 1991 had quit by the time of the reassessment.Zusammenfassung.Die Schweizer SAPALDIA-Kohortenstudie (SAPALDIA 2) 1991–2003: Methoden und TeilnehmendencharakteristikaFragestellung: Die Schweizer Kohortenstudie Luftverschmutzung und Atemwegserkrankungen bei Erwachsenen (SAPALDIA) untersucht die gesundheitlichen Auswirkungen der Langzeitbelastung durch Luftschadstoffe in der Bevölkerung.Methoden: 1991 und 2002 wurden ein Interview zur respiratorischen Gesundheit und deren Risikofaktoren, eine Spirometrie, ein bronchialer Reagibilitätstest mit Methacholin, eine endexpiratorische Kohlenmonoxidmessung und Tests zur allergischen Sensibilisierung durchgeführt. Für SAPALDIA 2 wurde eine Biobank mit Blut-, Serum-, Plasma- und DNA-Proben eingerichtet. Eine Stichprobe der über 50-jährigen Teilnehmenden erhielt ein 24-Stunden EKG (Holter). Luftschadstoffkonzentrationen von Stickstoffdioxid (NO2), Schwefeldioxid (SO2), Ozon (O3) und Schwebstaub (PM10) wurden in allen acht Studiengebieten seit 1991 gemessen. Die seit SAPALDIA 1 erfassten Adressgeschichten und auf GIS-Technologie beruhenden Schadstoffverteilungsdaten für NO2 und PM10 werden die Schätzung der individuellen Langzeitbelastung jedes SAPALDIA-Teilnehmenden ermöglichen.Ergebnisse: Von der ursprünglichen Kohorte von 9 651 Teilnehmern in 1991 waren 283 verstorben und Adressen konnten von 8715 aufgefunden werden. Basisinformationen zum Gesundheitszustand von 8047 Personen (86% aller lebenden Personen) wurden erfasst, 6528 (70%) nahmen an der Untersuchung teil und für 5973 (62%) liegen vollständige SAPALDIA2-Untersuchungen vor. Nichtteilnehmende waren im Durchschnitt jünger, weniger gut ausgebildet, eher Raucher und hatten eher respiratorische Symptome. Die untersuchten Personen haben in den letzten 11 Jahren durchschnittlich 5,5xa0kg Körpergewicht zugelegt, 28% der RaucherInnen haben aufgehört zu rauchen.Résumé.Etude de cohorte SAPALDIA (Etude Suisse sur la pollution atmosphérique et les maladies respiratoires chez l’adulte): méthodes et caractéristiques des participantsObjectifs: L’étude SAPALDIA a pour objectif de mesurer les effets sur la santé d’une exposition à long terme aux polluants atmosphériques dans la population adulte.Méthodes: Les participants ont été interrogés en 1991 et en 2002 sur leur état de santé respiratoire et ses facteurs de risque. Ils ont passé les examens suivants: spirométrie, test de la réactivité bronchique et de l’atopie, mesure du CO en fin d’expiration. Une banque biologique a été créée. Un ECG (Holter) a été pratiqué auprès d’un échantillon de participants âgés de plus de 50 ans. Les concentrations des polluants atmosphériques (dioxyde d’azote (NO2), dioxyde de soufre (SO2), ozone, particules fines (PM10)) ont été mesurées dans huit régions de Suisse depuis 1991. L’exposition individuelle sur 11 ans sera déterminée à partir des adresses, de la distribution de NO2 et PM10 et les modèles GIS.Résultats: Sur les 9 651 participants examinés en 1991, 283 sont décédés, 87 15 ont été localisés, 8047 ont donné des informations sur leur état de santé (86% des personnes en vie), 6 528 participants (70 %) ont accepté d’effectuer l’examen de santé et 5 973 (62 %) ont réalisé entièrement le protocole. Les non participants étaient en moyenne plus jeunes, moins éduqués, plus fréquemment fumeurs et souffraient plus fréquemment de symptômes respiratoires. Les personnes examinées ont pris en moyenne 5,5xa0kg de poids en 11 ans. 28% des fumeurs ont cessé de fumer.

Air pollution, oxidative stress and dietary supplementation: a review

The aim of the present review was to provide an up-to-date overview of the biological and epidemiological evidence of the role of oxidative stress as a major underlying feature of the toxic effect of air pollutants, and the potential role of dietary supplementation in enhancing antioxidant defences. A bibliographic search was conducted through PubMed. The keywords used in the search were “air pollutant”, “oxidative stress”, “inflammation”, “antioxidant polyunsaturated fatty acids” and “genetics”. In addition, the authors also searched for biomarkers of oxidative stress and nutrients. The review presents the most recent data on: the biological and epidemiological evidence of the oxidative stress response to air pollutants; the role of dietary supplementation as a modulator of these effects; and factors of inter-individual variation in human response. The methodology for further epidemiological studies will be discussed in order to improve the current understanding on how nutritional factors may act. There is substantial evidence that air pollution exposure results in increased oxidative stress and that dietary supplementation may play a modulating role on the acute effect of air pollutants. Further epidemiological studies should address the impact of supplementation strategies in the prevention of air-pollution-related long-term effects in areas where people are destined to be exposed for the distant future.

Smoking cessation, lung function, and weight gain : a follow-up study

BACKGROUNDnOnly one population-based study in one country has reported effects of smoking cessation and weight change on lung function, and none has reported the net effect. We estimated the net benefit of smoking cessation, and the independent effects of smoking and weight change on change in ventilatory lung function in the international European Community Respiratory Health Survey.nnnMETHODSn6654 participants in 27 centres had lung function measured in 1991-93, when aged 20-44 years, and in 1998-2002. Smoking information was obtained from detailed questionnaires. Changes in lung function were analysed by change in smoking and weight, adjusted for age and height, in men and women separately and together with interaction terms.nnnFINDINGSnCompared with those who had never smoked, decline in FEV1 was lower in male sustained quitters (mean difference 5.4 mL per year, 95% CI 1.7 to 9.1) and those who quit between surveys (2.5 mL, -1.9 to 7.0), and greater in smokers (-4.8 mL, -7.9 to -1.6). In women, estimates were 1.3 mL per year (-1.5 to 4.1), 2.8 mL (-0.8 to 6.3) and -5.1 mL (-7.5 to -2.8), respectively. These sex differences were not significant. FEV1 changed by -11.5 mL (-13.3 to -9.6) per kg weight gained in men, and by -3.7 mL per kg (-5.0 to -2.5) in women, which diminished the benefit of quitting by 38% in men, and by 17% in women.nnnINTERPRETATIONnSmoking cessation is beneficial for lung function, but maximum benefit needs control of weight gain, especially in men.

Increase in diagnosed asthma but not in symptoms in the European Community Respiratory Health Survey

Background: Information on the epidemiology of asthma in relation to age is limited and hampered by reporting error. To determine the change in the prevalence of asthma with age in young adults we analysed longitudinal data from the European Community Respiratory Health Survey. Methods: A self-administered questionnaire was completed by 11 168 randomly selected subjects in 14 countries in 1991–3 when they were aged 20–44 years and 5–11 years later from 1998 to 2003. Generalised estimating equations were used to estimate net change in wheeze, nocturnal tightness in chest, shortness of breath, coughing, asthma attacks in the last 12 months, current medication, “diagnosed” asthma, and nasal allergies. Results: Expressed as change in status per 10 years of follow up, subjects reporting asthma attacks in the previous 12 months increased by 0.8% of the population (95% CI 0.2 to 1.4) and asthma medication by 2.1% (95% CI 1.6 to 2.6), while no statistically significant net change was found in reported symptoms. Reported nasal allergies increased, especially in the youngest age group. Conclusions: As this cohort of young adults has aged, there has been an increase in the proportion treated for asthma but not in the proportion of those reporting symptoms suggestive of asthma. Either increased use of effective treatments has led to decreased morbidity among asthmatic subjects or those with mild disease have become more likely to label themselves as asthmatic.

Lung function in healthy never smoking adults: reference values and lower limits of normal of a Swiss population.

BACKGROUND: Reference values and definitions of normal are prerequisites for population screening and classification of lung diseases. The aim of this study was to calculate reference values for never smoking Caucasian adults. METHODS: In the SAPALDIA cross sectional study respiratory health was assessed in a random sample of 9651 subjects, aged 18-60 years, from eight areas of Switzerland. Lung function was measured according to ATS criteria including quality control. In 3157 healthy never smoking adults without respiratory symptoms the mean values and fifth percentiles of lung function variables were calculated. For each sex, logarithms of lung function were regressed against age, age squared, and the logarithm of height. Residuals were used to estimate fifth percentiles across the age range using a technique not requiring normality or homoscedasticity of residuals. RESULTS: Most lung function variables were non-linear with age and showed an increase in early adulthood and an accelerated decline thereafter. The reference values for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were higher than those of the European Community for Coal and Steel and those from North America. The prediction equations for lower fifth percentile values defined a stable proportion of subjects outside this limit whereas alternative methods for estimating the fifth percentile showed a loss of sensitivity with age. CONCLUSIONS: The reference equations for mean values of spirometric indices and their lower fifth percentiles gave an improved and unbiased lower limit of normal. The higher mean values may in part be due to the strictly selected population, quality control procedures, cohort effects, and altitude, and are not explained by the statistical model used.

Traffic-Related Air Pollution Correlates with Adult-Onset Asthma among Never-Smokers

Background: Traffic-related pollution is associated with the onset of asthma in children. Its effect on adult-onset asthma is poorly investigated. The SAPALDIA cohort study was used to investigate associations between the 11-year change (1991–2002) in home outdoor traffic-related particulate matter up to 10 μm in diameter (TPM10) and the incidence of asthma. Methods: Never-smokers without asthma at baseline aged 18–60 years in 1991 were eligible for inclusion in the study. Subjects reporting doctor-diagnosed asthma at follow-up were considered incident cases. TPM10 at baseline and follow-up was predicted and interpolated to subjects’ place of residence by dispersion models using emission and meteorological data. Cox proportional hazard models for time to asthma onset were adjusted (age, gender, baseline atopy, body mass index, bronchial reactivity, maternal allergies). Results: Of 2725 never-smokers, 41 reported asthma onset in 2002. Home outdoor TPM10 concentrations improved during the interval (mean −0.6; range −9 to +7.2; IQR 0.6 μg/m3). The incidence of asthma was associated with a change in TPM10. The hazard ratio (1.30; 95% CI 1.05 to 1.61) per 1 μg/m3 change in TPM10 (IQR) was not sensitive to further adjustments (education, workplace exposure, passive smoking, parental asthma or allergies, random area effects, lung function or co-pollutants such as regional, secondary, total PM10 or proximity to busy roads). Conclusion: The data suggest a role for traffic-related pollution in adult-onset asthma. Space, time and source-specific individual assignment of exposure to traffic-related pollution is a key strength of SAPALDIA. It may explain why findings were statistically significant despite the limited number of new cases. As traffic-related pollution prevails, the finding may be of substantial public health relevance.

Chronic bronchitis and urban air pollution in an international study

Objectives: The chronic effects of urban air pollution are not well known. The authors’ aim was to investigate the association between the prevalence and new onset of chronic bronchitis and urban air pollution. Methods: Subjects from the general population randomly selected for the European Community Respiratory Health Survey (ECRHS I) during 1991–93 in 21 centres in 10 countries were followed up from the years 2000 to 2002 (nu200a=u200a3232 males and 3592 females; average response rateu200a=u200a65.3%). PM2.5 and elements, with the same equipment at centre level, and home outdoor NO2 in 1634 individuals were measured. Hierarchical models were used. Results: The prevalence and new onset of chronic phlegm during follow up were 6.9% and 4.5%, respectively, 5.3% in males and 3.5% in females. Smoking, rhinitis, poor education, and low social class were associated with (prevalence and new onset of) chronic phlegm in both genders, and occupational exposures in males and traffic intensity (adjusted odds ratio for constant traffic, ORu200a=u200a1.86; 95% CI 1.24 to 2.77) as well as home outdoor NO2 (OR > 50 μg/m3v < 20μg3 u200a=u200a 2.71; 95% CI 1.03 to 7.16) among females. PM2.5 and S content at centre level did not show any association with prevalence or new onset of chronic phlegm. Similar results were obtained with chronic productive cough. Conclusion: Individual markers of traffic at household level such as reported intensity and outdoor NO2 were risk factors for chronic bronchitis among females.

Asthma score: predictive ability and risk factors

Background:u2002 Definition of asthma as a continuous score is a promising tool for population studies that has not yet been fully evaluated.