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Biomedical subjects

N Künzli

Publications and source records attributed to N Künzli.

At least 19 recordsLinked to original sources
PubMed2006

Incidence of asthma and net change in symptoms in relation to changes in obesity.

The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males.

Adult↗
PubMed2006

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 (n = 3232 males and 3592 females; average response rate = 65.3%). 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, OR = 1.86; 95% CI 1.24 to 2.77) as well as home outdoor NO2 (OR > 50 microg/m3v < 20 microg3 = 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.

Adult↗
PubMed2006

Evaluation of a sampling strategy for estimation of long-term PM2.5 exposure for epidemiological studies.

As part of the European Community Respiratory Health Survey (ECRHS) PM2.5 (particles collected with an upper 50% cut point of 2.5 microm aerodynamic diameter) was measured using an EPA-WINS (Environmental Protection Agency Well Impactor Ninety-six) sampler. The monitoring schedule was restricted to 7 days per month for one year. Simultaneously, during this one year study period a collocated Harvard Impactor (HI) was run on a daily basis in Erfurt, Germany. Here we validated the reliability of annual, seasonal and monthly means estimated using the ECRHS scheme (measurements taken less than 25% of the whole study period) with the 'true' long-term averages, which were estimated using all available daily means. The daily PM2.5 means, obtained by both instruments operated in parallel, were only slightly different (the mean difference between EPA-WINS and HI was 1.8 microg m(-3) and 2.8 microg m(-3) for the winter means). The values obtained by the two instruments were highly correlated (r = 0.95). In view of that negligible difference, no additional bias was seen with respect to the annual and the winter means estimated by the two different sampling strategies (the difference was 1.7 microg m(-3) and 2.7 microg m(-3), respectively). Monthly means, however, can only be considered to be a crude estimate that may substantially under- or overestimate the true monthly mean value.

Air Pollutants↗
PubMed2006

Changes in active and passive smoking in the European Community Respiratory Health Survey.

The aim of the present investigation was to study changes and determinants for changes in active and passive smoking. The present study included 9,053 adults from 14 countries that participated in the European Community Respiratory Health Survey II. The mean follow-up period was 8.8 yrs. Change in the prevalence of active and passive smoking was expressed as absolute net change (95% confidence interval) standardised to a 10-yr period. Determinants of change were analysed and the results expressed as adjusted hazard risk ratio (HRR) or odds ratio (OR). The prevalence of active smoking declined by 5.9% (5.1-6.8) and exposure to passive smoking in nonsmokers declined by 18.4% (16.8-20.0). Subjects with a lower educational level (HRR: 0.73 (0.54-0.98) and subjects living with a smoker (HRR: 0.45 (0.34-0.59)) or with workplace smoking (HRR: 0.69 (0.50-0.95)) were less likely to quit. Low socio-economic groups were more likely to become exposed (OR: 2.21 (1.61-3.03)) and less likely to cease being exposed to passive smoking (OR: 0.48 (0.37-0.61)). In conclusion, the quitting rate was lower and the risk of exposure to passive smoking higher among subjects with lower socio-economic status. Exposure to other peoples smoking decreased quitting rates and increased the risk of starting to smoke.

Adult↗
PubMed2004

An international survey of chronic obstructive pulmonary disease in young adults according to GOLD stages.

BACKGROUND: The recently published GOLD guidelines provide a new system for staging chronic obstructive pulmonary disease (COPD) from mild (stage I) to very severe (stage IV) and introduce a stage 0 (chronic cough and phlegm without airflow obstruction) that includes subjects "at risk" of developing the disease. METHODS: In order to assess the prevalence of GOLD stages of COPD in high income countries and to evaluate their association with the known risk factors for airflow obstruction, data from the European Community Respiratory Health Survey on more than 18,000 young adults (20-44 years) were analysed. RESULTS: The overall prevalence was 11.8% (95% CI 11.3 to 12.3) for stage 0, 2.5% (95% CI 2.2 to 2.7) for stage I, and 1.1% (95% CI 1.0 to 1.3) for stages II-III. Moderate to heavy smoking (> or =15 pack years) was significantly associated with both stage 0 (relative risk ratio (RRR)=4.15; 95% CI 3.55 to 4.84) and stages I+ (RRR=4.09; 95% CI 3.17 to 5.26), while subjects with stages I+ COPD had a higher likelihood of giving up smoking (RRR=1.39; 95% CI 1.04 to 1.86) than those with GOLD stage 0 (RRR=1.05; 95% CI 0.86 to 1.27). Environmental tobacco smoke had the same degree of positive association in both groups. Respiratory infections in childhood and low socioeconomic class were significantly and homogeneously associated with both groups, whereas occupational exposure was significantly associated only with stage 0. All the GOLD stages showed a significantly higher percentage of healthcare resource users than healthy subjects (p<0.001), with no difference between stage 0 and COPD. CONCLUSIONS: A considerable percentage of young adults already suffered from COPD. GOLD stage 0 was characterised by the presence of the same risk factors as COPD and by the same high demand for medical assistance.

Adult↗
PubMed2004

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.

Adult↗
PubMed2003

Smoke-free cafe in an unregulated European city: highly welcomed and economically successful.

OBJECTIVE: In a unique setting with two identical cafes, which only differed in their smoking ordinances, this study assessed the influence of smoking policies on the choice of the cafe, investigated regulatory preferences among customers, and evaluated the claim that smoking cafes have better sales performance in a city without smoking bans. METHODS: In a parallel assessment, customers of both cafes answered a questionnaire. Sales were compared and air pollutants were measured to confirm air quality differences. RESULTS: The two customer groups (n = 177) differed only with regard to smoking status (p < 0.01). The smoking regulation was the most often cited selection criterion (83%). In the non-smoking café, 89% indicated that they were usually annoyed by smoke in coffee houses, and 62% would avoid or leave cafes for this reason. Two thirds stated that all cafe/restaurants should offer the opportunity of a smoke-free environment. However, almost half stated that mandatory regulations are not needed and that customers should make individual arrangements based on tolerance and courtesy. Those who were informed about the health effects of secondhand smoke were more likely to call for clear policies. Whereas sales showed no differences, tips were 22% (p < 0.001) higher in the non-smoking cafe. CONCLUSION: In a generation raised in smoking friendly environments, customers paradoxically ask for a landmark shift towards smoke-free opportunities, while substantially adhering to the tobacco industry paradigm of promoting "tolerance" rather than smoke-free policies. Given the clear preference of a large number of customers, hospitality businesses could, however, greatly profit from offering smoke-free environments even in the absence of regulatory policies.

Adult↗
PubMed2002

The public health relevance of air pollution abatement.

Assuming a causal relationship between current levels of air pollution and morbidity/mortality, it is crucial to estimate the public health relevance of the problem. The derivation of air pollution attributable cases faces inherent uncertainties and requires influential assumptions. Based on the results of the trinational impact assessment study of Austria, France, and Switzerland, where prudent estimates of the air pollution attributable cases (mortality, chronic bronchitis incidence, hospital admissions, acute bronchitis among children, restricted activity days, asthma attacks) have been made, influential uncertainties are quantified in this review. The public health impact of smoking, environmental tobacco smoke, and air pollution on the prevalence of chronic cough/phlegm are outlined. Despite all methodological caveats, impact assessment studies clearly suggest that public health largely benefits from better air quality. The studies are selective underestimates as they are strongly driven by mortality, but do not include full quantification of the impact on morbidity and their consequences on quality of life among the diseased and the caregivers. Air pollution abatement strategies are usually political in nature, targeting at polities, regulation and technology in mobile or stationary sources rather than at individuals. It is of note that key clean air strategies converge into abatement of climate change. In general, energy consumption is very closely related to both air pollution and greenhouse gases. The dominant causes of both problems are the excessive and inefficient combustion of fossil fuel. Thus, for many policy options, the benefit of air pollution abatement will go far beyond what prudent health-impact assessments may derive. From a climate change and air pollution perspective, improved energy efficiency and a strong and decisive departure from the "fossil fuel" combustion society is a science-based must. Health professionals must raise their voices in the political decision process to give strong support for clean air policies, both on a national and international level.

Air Pollution↗
PubMed2001

Assessment of deaths attributable to air pollution: should we use risk estimates based on time series or on cohort studies?

Epidemiologic studies are crucial to the estimation of numbers of deaths attributable to air pollution. In this paper, the authors present a framework for distinguishing estimates of attributable cases based on time-series studies from those based on cohort studies, the latter being 5-10 times larger. The authors distinguish four categories of death associated with air pollution: A) air pollution increases both the risk of underlying diseases leading to frailty and the short term risk of death among the frail; B) air pollution increases the risk of chronic diseases leading to frailty but is unrelated to timing of death; C) air pollution is unrelated to risk of chronic diseases but short term exposure increases mortality among persons who are frail; and D) neither underlying chronic disease nor the event of death is related to air pollution exposure. Time-series approaches capture deaths from categories A and C, whereas cohort studies assess cases from categories A, B, and C. In addition, years of life lost can only be derived from cohort studies, where time to death is the outcome, while in time-series studies, death is a once-only event (no dimension in time). The authors conclude that time-series analyses underestimate cases of death attributable to air pollution and that assessment of the impact of air pollution on mortality should be based on cohort studies.

Air Pollutants↗
PubMed2001

Respiratory symptoms in Swiss farmers: an epidemiological study of risk factors.

BACKGROUND: The study was undertaken to assess the prevalence and risk factors of self-reported asthma, symptoms of chronic bronchitis, hay fever, and work-related respiratory symptoms in Swiss farmers as well as to compare the prevalence rates of respiratory symptoms with the Swiss population (SAPALDIA-Study). METHODS: An epidemiological study was performed with a representative sample of 1,542 Swiss farmers using a self-administered questionnaire. To investigate the effect of the type of farming on reported symptoms, the farmers were subdivided into seven groups according to the time farmers spent in different animal confinement buildings. A multivariate analysis was performed by the methods of binary and multivariate logistic regression adjusted for age and smoking habits. RESULTS: In farmers the prevalence rate was 16.0% for chronic bronchitis, 15.4% for asthma symptoms, and 42.0% for reporting at least one work-related symptom. Using logistic regression analysis, it was established that poultry farming and pig/cattle farming was a risk factor for reporting nasal irritation at work [OR 5.33, (1.57-18.0), OR 3.37 (1.04-10.87)]. Poultry farmers experienced the highest symptom rates. In crop farmers, the prevalence for chronic bronchitis was increased [OR 2.32 (1.03-5.23)]. Over 4 hr spent per day in animal confinement buildings more than doubled the risk for reporting chronic bronchitis [OR 2.61 (1.01-6.76)] and phlegm [OR 2.3 (0.99-5.4)] independent of the type of farming. The comparison of Swiss farmers with the Swiss population showed a twofold elevated risk of reporting chronic bronchitis [OR 1.89 (1.32-2.95)] and a 4.5-fold elevated risk for bringing up phlegm regularly [OR 4.5 (3.25-6.69)] in farmers. In contrast, the risk of farmers to report nasal allergies was less than half as high [OR 0.40 (0.29-0.56)] as that of the general population. CONCLUSIONS: This study shows that agricultural work in Switzerland is associated with an elevated risk for reporting symptoms of chronic bronchitis and chronic phlegm compared with the general Swiss population. These main results most likely indicate occupational disorders as the exposure-response relationship (hours spent in animal confinements) was particularly obvious for these symptoms.

Adolescent↗
PubMed2001

Short-term variation in air pollution and in average lung function among never-smokers. The Swiss Study on Air Pollution and Lung Diseases in Adults (SAPALDIA).

The present analysis was directed at investigating associations between short-term variations in air pollutant levels (NO2, total suspended particulates [TSP], O3) and cross-sectional lung function (FVC, FEV1, and forced expiratory flow at 25% to 75% of FVC [FEF25-75]) within a random sample of 3,912 adult never-smokers from eight areas of Switzerland (i.e., participants in the Swiss Study on Air Pollution and Lung Diseases in Adults [SAPALDIA] cross-sectional study, 1991). Within each local data set, the logarithms of FVC, FEV1, and FEF25-75 were regressed against the 24-h-means of NO2 and TSP and the 8-h mean of O3 (10:00 A.M. to 6:00 P.M.) on the examination day, with control for subjects' sex, age, height and weight, seasonal fluctuations and weekly cycles and meteorologic factors. On average, a 10-microg/m3 increment in the daily level of NO2, TSP, and O3 was associated with decrements in FEV1 of 0.67% (95% confidence interval [CI]: 0.13% to 1.21%), 0.46% (95% CI: 0.14% to 0.78%), and 0.51% (95% CI: 0.13% to 0.88%), respectively. Moreover, 10-microg/m3 increments in NO2 and TSP were associated with decrements in FVC of 0.73% (95% CI: 0.22% to 1.23%) and 0.36% (95% CI: 0.06% to 0.66%), respectively, and a 10-microg/m3 increment in O(3) was associated with a decrement in FEF25-75 of 1.04% (95% CI: 0.22% to 1.85%). Our results suggest that FVC, FEV1, and FEF25-75 vary with the daily level of NO2, TSP, and O3, but that these measures of lung function do not allow separation of the effects of particulates from those of NO2.

Adolescent↗
PubMed2000

Public-health impact of outdoor and traffic-related air pollution: a European assessment.

BACKGROUND: Air pollution contributes to mortality and morbidity. We estimated the impact of outdoor (total) and traffic-related air pollution on public health in Austria, France, and Switzerland. Attributable cases of morbidity and mortality were estimated. METHODS: Epidemiology-based exposure-response functions for a 10 microg/m3 increase in particulate matter (PM10) were used to quantify the effects of air pollution. Cases attributable to air pollution were estimated for mortality (adults > or = 30 years), respiratory and cardiovascular hospital admissions (all ages), incidence of chronic bronchitis (adults > or = 25 years), bronchitis episodes in children (< 15 years), restricted activity days (adults > or = 20 years), and asthma attacks in adults and children. Population exposure (PM10) was modelled for each km2. The traffic-related fraction was estimated based on PM10 emission inventories. FINDINGS: Air pollution caused 6% of total mortality or more than 40,000 attributable cases per year. About half of all mortality caused by air pollution was attributed to motorised traffic, accounting also for: more than 25,000 new cases of chronic bronchitis (adults); more than 290,000 episodes of bronchitis (children); more than 0.5 million asthma attacks; and more than 16 million person-days of restricted activities. INTERPRETATION: This assessment estimates the public-health impacts of current patterns of air pollution. Although individual health risks of air pollution are relatively small, the public-health consequences are considerable. Traffic-related air pollution remains a key target for public-health action in Europe. Our results, which have also been used for economic valuation, should guide decisions on the assessment of environmental health-policy options.

Adolescent↗
PubMed2000

Validity of annoyance scores for estimation of long term air pollution exposure in epidemiologic studies: the Swiss Study on Air Pollution and Lung Diseases in Adults (SAPALDIA).

In air pollution epidemiology, estimates of long term exposure are often based on measurements made at one fixed site monitor per area. This may lead to exposure misclassification. The present paper validates a questionnaire-based indicator of ambient air pollution levels and its applicability to assess their within-area variability. Within the framework of the SAPALDIA (Swiss Study on Air Pollution and Lung Diseases in Adults) cross-sectional study (1991), 9,651 participants reported their level of annoyance caused by air pollution on an 11-point scale. This subjective measure was compared with annual mean concentrations of particulate matter less than 10 microm in diameter (PM10) and nitrogen dioxide. The impact of individual factors on reported scores was evaluated. Nitrogen dioxide concentrations at home outdoors (measured in 1993), smoking, workplace dust exposure, and respiratory symptoms were found to be predictors of individual annoyance scores. Regression of population mean annoyance scores against annual mean PM10 and nitrogen dioxide concentrations (measured in 1993 and 1991, respectively) across areas showed a linear relation and strong correlations (r>0.85). Analysis within areas yielded consistent results. The observed associations between subjective and objective air pollution exposure estimates suggest that population mean scores, but not individual scores, may serve as a simple tool for grading air quality within areas. Reported annoyance due to air pollution should be considered an indicator for a complex environmental condition and thus might be used for evaluating the implementation of environmental policies.

Adolescent↗
PubMed2000

[SAPALDIA: past, present and future].

The cross-sectional part of SAPALDIA studied the associations between respiratory symptoms or functional abnormalities and chronic exposure to a polluted environment. The results showed an elevated risk of developing respiratory symptoms in regions with higher levels of particulate matters (PM10). The same was observed with passive smoking exposure. Decreased spirometric parameters (especially FVC) were measured in areas with the highest levels of PM10. While the functional alteration is clinically minimal in the individual, the effect is significant when one considers the prevalence of an abnormal functional parameter in a general population. Exposure to pollutants at the workplace increases bronchial reactivity to non-specific stimuli, with atopy acting as amplifier of this effect. The longitudinal part of SAPALDIA examined the associations between the dynamics of respiratory symptoms or functional abnormalities and average levels, as well as short-term fluctuations, of atmospheric pollutants. It was observed that symptomatic episodes tend to last longer in more polluted regions, whichever marker of pollution is used (PM10 or NO2). Passive smoking tends to prolong respiratory symptoms and shorten asymptomatic intervals. Short-term increases in outdoor pollutants are associated with an increase in incidence of peak flows below individual baseline values. Numerous questions remain regarding the relationship between respiratory health and environment. A SAPALDIA II study is under preparation which will follow the evolution of SAPALDIA I participants with regard to respiratory symptoms, pulmonary function, bronchial reactivity and markers of atopy.

Air Pollution↗
PubMed2000

Association of environmental tobacco smoke at work and forced expiratory lung function among never smoking asthmatics and non-asthmatics. The SAPALDIA-Team. Swiss Study on Air Pollution and Lung Disease in Adults.

Inconsistencies across studies on the association of environmental tobacco smoke (ETS) and pulmonary function may be clarified addressing potentially susceptible subgroups. We determined the association of ETS exposure at work with FVC, FEV1, and FEF25-75% in life-time never smokers (N = 3534) of the SAPALDIA random population sample (age 18-60). We considered sex, bronchial reactivity, and asthma status as a priori indicators to identify susceptible riskgroups. The multivariate regression models adjusted for height, age, education, dust/aerosol exposure, region, and ETS at home. Overall, ETS was not significantly associated with FVC (0.7%; -0.4 to +1.8), FEV1 (-0.1%; 95% CI: -1.3 to +1.1) or FEF25-75% (-1.9%; -4.2 to +0.5). Effects were observed among asthmatics (n = 325), FEV1 (-4.8%; 0 to -9.2); FEF25-75% (-12.4%; -3.7 to -20.4); FVC: (-1.7%; +2.1 to -5.5), particularly in asthmatic women (n = 183): FVC -4.4% (-9.6 to +1.1); FEV1: -8.7% (-14.5 to -2.5); FEF25-75%: -20.8% (-32 to -7.6), where duration of ETS exposure at work was associated with lung function (FEV1 -6% per hour of ETS exposure at work (p = 0.01); FEF25-75%: -3.4%/h (p < 0.05). In non-asthmatic women (n = 1963) and in men no significant effect was observed. The size of the observed effect among susceptible subgroups has to be considered clinically relevant. However, due to inherent limitations of this cross-sectional analysis, selection or information biases may not be fully controlled. For example, asthmatic women reported higher ETS exposure at work than asthmatic men. Given the public health importance to identify susceptible subgroups, these results ought to be replicated.

Adolescent↗
PubMed2000

Validity of ambient levels of fine particles as surrogate for personal exposure to outdoor air pollution--results of the European EXPOLIS-EAS Study (Swiss Center Basel).

To evaluate the validity of fixed-site fine particle levels as exposure surrogates in air pollution epidemiology, we considered four indicator groups: (1) PM2.5 total mass concentrations, (2) sulfur and potassium for regional air pollution, (3) lead and bromine for traffic-related particles, and (4) calcium for crustal particles. Using data from the European EXPOLIS (Air Pollution Exposure Distribution within Adult Urban Populations in Europe) study, we assessed the associations between 48-hr personal exposures and home outdoor levels of the indicators. Furthermore, within-city variability of fine particle levels was evaluated. Personal exposures to PM2.5 mass were not correlated to corresponding home outdoor levels (n = 44, rSpearman (Sp) = 0.07). In the group reporting neither relevant indoor sources nor relevant activities, personal exposures and home outdoor levels of sulfur were highly correlated (n = 40, rSp = 0.85). In contrast, the associations were weaker for traffic (Pb: n = 44, rSp = 0.53; Br: n = 44, rSp = 0.21) and crustal (Ca: n = 44, rSp = 0.12) indicators. This contrast is consistent with spatially homogeneous regional pollution and higher spatial variability of traffic and crustal indicators observed in Basel, Switzerland. We conclude that for regional air pollution, fixed-site fine particle levels are valid exposure surrogates. For source-specific exposures, however, fixed-site data are probably not the optimal measure. Still, in air pollution epidemiology, ambient PM2.5 levels may be more appropriate exposure estimates than total personal PM2.5 exposure, since the latter reflects a mixture of indoor and outdoor sources.

Adult↗