[Air pollution in Switzerland--quantification of health effects using epidemiologic data]. / Luftverschmutzung in der Schweiz--Quantifizierung gesundheitlicher Effekte unter Verwendung epidemiologischer Daten.

Public health costs ascribable to air pollution are socialized in our society. To quantify the damage to public health, epidemiologic studies are needed. We present the methods and epidemiologic background data which form the basis for estimating the public health effect ascribable to air pollution. The figures are presented per 1 million "average" Swiss population and per 10 micrograms/m3 increase in long-term annual mean particulate pollution (PM10). Quantification was restricted to the health effects given below (due to lack of complete data for other effects or to avoid duplicating health effects which may be described by overlapping measurements). In parenthesis we present (1) the mean effect estimates (+/-1 SE) (% increase per 10 micrograms/m3 increment in PM10) derived from national and international epidemiologic studies, and (2) the expected absolute additional health effects (+/-1 SE) per 1 million Swiss population and per 10 micrograms/m3 increment in PM10, based on Swiss population statistics: total mortality (long-term estimates from the 2 US cohort studies) (+4.4% [+/-1.1]/349 [+/-91] premature deaths per year); prevalence of chronic bronchitis in adults (+25% [+8.4]/increase in long-term prevalence by 3,513 [+/-1.475]); bronchitis among children (35% [+/-13]/5,180 [+/-2,590] additional children sufferers in a year); repeated cough among children (+54% [+/-8.8]/23,490 [+/-5,873] additional children per year); cough/phlegm in adults (+12.8% [+/-7.8]/1.56 [+/-1.08] million person-days per year); hospital admissions for respiratory diseases (+1.47% [+/-0.5]/71 [+/-24] additional admissions or 1,104 (+/-390) hospital days); admissions for cardiovascular diseases (+0.9% [+/-0.25]/70 [+19] admissions; 970 (+/-270) hospital days); restricted activity days (+10.5% [+/-0.77]/0.42 [+/-0.03] million person-days); days with asthma attacks among the 6.7% asthmatics (Swiss prevalence) (+5.3% [+/-2.1]/ 240,000 [+/-102,000] additional person-days). Conservative assumptions were used throughout the study and thus the true effects are likely to be larger. Estimates of Swiss population exposure distribution would be needed to apply these results to the entire population. This step, and monetary quantification of these total effects, were the second and third elements (not shown in this report) of this Swiss government funded project. Although individual relative risks of air pollution are rather slight, the public health burden of even moderate pollution may be substantial.

Particulate matter less than 10 microns (PM10) and fine particles less than 2.5 microns (PM2.5): relationships between indoor, outdoor and personal concentrations.

Among 17 homes in Switzerland, the relationship between indoor and outdoor levels for particulate matter less than 10 microns (PM10), particulate matter less than 2.5 microns (PM2.5) and NO2 was investigated. In 10 homes, the inhabitants also participated in conducting personal measurements. All homes were naturally ventilated. In homes without any indoor sources and where human activity was low, PM10 I/O ratios amounted to approximately 0.7. Of the indoor sources, smoking had the highest influence on I/O ratios (> 1.8). In homes not containing any apparent source, 'human activity' was an important factor accounting for high indoor levels. However, this factor is difficult to quantify. Personal exposure was in most cases higher than the indoor and the corresponding home outdoor levels. For NO2, gas-cooking was found to have the strongest influence on elevated I/O ratios (> 1.2) whilst for other homes, the I/O ratio was less than 1.

Direct determination of allergens in ambient aerosols: methodological aspects.

In Switzerland the birch tree (Betula verrucosa) major allergen Bet v 1 and the grass (Phleum pratense) pollen major allergen Phl p 5 are of particular relevance for inducing pollinosis. In this study, the protein and major allergen contents of aerosols of different aerodynamic diameters were determined. The aerosols were sampled by Andersen-Impactors and submitted to protein assays and allergen assays (ELISA) specific for Bet v 1 and Phl p 5. The total protein, Bet v 1 and Phl p 5 concentrations were correlated with the corresponding pollen counts. The presence of Bet v 1 in smaller aerosol fractions was demonstrated before and after birch pollen was counted, especially in the lower particle size ranges.

Effects of atmospheric pollution on human health.

Most air pollutants do not lead to specific diseases. Depending on the pollutant, the concentration and the duration of exposure, some organs are more affected than others. The most frequent disorders are those caused by irritant gases and particulates on the mucous membranes and respiratory organs. The consequences are eye, nose and throat inflammations, diminished lung function, increased susceptibility to respiratory infection and a higher incidence of chronic bronchitis. These disorders and diseases are, of course, influenced by other factors as well, such as immune deficiency, allergies, occupational exposure to pollutants, and particularly smoking. The effects of air pollutants are, therefore, multifactorially conditioned and nonspecific disorders are placed in the foreground. Evidence for an association of air pollution with adverse effects on human health is drawn from three sources: animal experiments, experimental human exposures, and epidemiologic studies of exposed human populations. The burden of atmospheric pollution must be reduced to protect human health by an adequate safety margin. In particular, the increased sensitivity of sick and aged people as well as children should be taken into account. In defining the maximum emission levels, preventive aspects should have priority so as to keep the risk of damage to health and the harmful influences on the environment to a minimum.

Sources of pollutants in indoor air.

In order to ensure an impeccable indoor air quality, it is important to do so, whenever possible, by means of source-control. In particular, this general principle should be applied with regard to contamination originating from building materials and furnishings. For such materials, quality requirements should be established to keep the concentration of emitted pollutants below admissible limits. In the case of building materials, a general declaration of all constituents should be mandatory and carcinogenic compounds like asbestos and benzene should be prohibited for use in indoor environments. If the emission of a specific pollutant cannot be avoided, its concentration in indoor air can be kept below the tolerated limit by increasing the ventilation. Increased concentrations of nitrogen dioxide due to the use of combustion appliances in kitchens and bathrooms can be avoided by exhausts. In geographical areas with high radon emission, however, corrective measures have to be evaluated individually. To eliminate the contaminants originating from human activities (e.g., carbon dioxide, body odours), adequate ventilation is required and depends on the occupancy and the use of the room; to maintain an acceptable air quality, the carbon dioxide concentration should not exceed 0.1-0.15%. Increased ventilation also reduces acute irritations if smoking is allowed. Here, the required air supply is dependent on the degree of annoyance which is considered to be acceptable to the user of the room. Acceptable indoor air quality can largely be maintained today because of the extensive knowledge and experience now accumulated in this field. However, the complex relationships between air quality and human health require further study. More research in the field of building materials is particularly desirable.

[Perception of traffic noise emission in Basel City canton in comparison to actually measured noise levels]. / Die Wahrnehmung der Verkehrslärmimmissionen im Kanton Basel-Stadt im Vergleich zu den erhobenen Lärmmesswerten.

The objective of this study was to assess to what extent the subjective annoyance is influenced by the actually measured or calculated street traffic noise and by sociodemographic factors. In the study on air pollution and health in Basle a representative sample of 1033 families with children up to five years were asked how they perceived street traffic noise. The extent of annoyance was assessed with a scale from 0 (no annoyance) to 10 (unbearably annoyed). The actual noise levels were taken from the official noise-register. Nearly 30% of the families were exposed to > 65 dB(A) in daytime. Immigrant families as well as participants with low education more frequently lived in streets with higher noise levels than Swiss families or participants with higher education. 16.4% considered themselves heavily annoyed by traffic noise (scale 8-10). The proportion of heavily annoyed participants was positively correlated with the actual noise levels, the slope was steepest at a noise level between 60-65 dB(A). By means of a multiple regression it could be shown that, adjusting for education level and city district, the actual noise level was the best predictor of subjective annoyance.

Air pollution and respiratory symptoms in preschool children.

A diary study on a random sample of 625 Swiss children aged 0 to 5 yr was conducted in two cities in Switzerland to investigate the association between air pollution and respiratory symptoms. Total suspended particulates (TSP), SO2 and NO2 were measured by city monitor. In addition, passive samplers inside and outside the home measured NO2 concentration during the 6 wk each child was on the diary. Diaries were filled out by parents, and 20% were validated with the attending pediatrician's case notes. Incidence and duration of symptom episodes were examined separately. The study included any episode, episodes of coughing without runny nose, upper respiratory episodes, and episodes of breathing difficulty. In regressions using 6-wk average pollution that controlled for medical history, NO2 measured outdoors but not indoors was associated with the duration of any symptom. Total suspended particulates were a more significant predictor of duration of any symptom than NO2. The 6-wk average TSP was significantly associated with incidence of coughing episodes and marginally significant as a predictor of upper respiratory episodes. Previous day's TSP was a significant predictor of incidence of upper respiratory symptoms. Annual average of NO2 was associated with the duration of any episode and of upper respiratory episodes. We conclude that the incidence and duration of respiratory symptom episodes are likely associated with particulate concentrations and duration may be associated with NO2.

The environmental accident at 'Schweizerhalle' and respiratory diseases in children: a time series analysis.

During an investigation concerned with the relationship between air pollution and respiratory diseases in children, the 'Schweizerhalle' accident occurred when unknown amounts of pollutants were discharged into the environment. In that investigation, two series of medical data were collected during one year: (a) The daily relative number of preschool children, exhibiting diseases of the respiratory tract, who either came to the outpatients' clinic of the Children's Hospital or were reported by paediatricians in Basle; (b) The daily number of respiratory symptoms per child, observed in a group of randomly selected preschool children. The purpose of the present time series analysis is the assessment of possible change in these series after the environmental accident. The nature of the change is studied by complementary approaches. First, a forecast arising from models identified in the preaccident period is compared with the actual data. Thereafter, intervention models which adequately and parsimoniously represent the change are identified. Finally, an identification of a change-point is performed.

[Effects of jogging on mental well-being and seasonal mood variations: a randomized study with healthy women and men]. / Effekte von Jogging auf psychisches Befinden und saisonale Stimmungs-schwankungen: Eine randomisierte Studie mit gesunden Frauen und Männern.

The long-term effect of jogging on mental well-being and seasonal mood variation was examined in a randomized, controlled intervention study with healthy, middle-aged, sedentary, non-smoking, white collar subjects. 17 women and 39 men were allocated to jog 2 h/week for 4 months, whereas 16 women and 22 men served as controls. After 4 months, there was a partial cross-over with the controls now taking up jogging. After 8 study months, all 38 subjects of the second jogging intervention as well as 10 women and 30 men of the first 4-month jogging period were re-examined for the second time. All participants in the second re-examination were mailed a survey questionnaire one year after beginning of the study (response rate 83%). Despite varying adherence for the exercise regimen, the 4-month "net effects" (i.e. effect in exercise group minus effect in control group) showed a significant improvement in physical fitness (endurance capacity, resting heart rate) in men, but not in women. Among the mood scales assessed, "anger" showed a marginally significant effect in men (relative decrease; p = 0.05) and "calmness" a significant effect in women (relative increase; p = 0.02); after exclusion of 4 non-compliers from analysis in women, also "vigor" (relative increase; p = 0.03) and "depressiveness" (relative decrease; p = 0.02) were significantly improved after jogging. In women, the number of kilometers run was significantly correlated with an improvement in mental well-being (Pearson's r = 0.32 with change in 4 "positive" mood scales and r = 0.57 with change in 4 "negative" mood scales). Changes in endurance capacity were not significantly related to changes in mental well-being. However, in both women and men these mental effects of jogging were superposed by clear seasonal variations in mood, i.e. by a deterioration of mental well-being during the winter months and by a slow "remission" during summer. Taking jogging-induced and seasonal effects on mood together, the magnitude of the 1-year variability in mental well-being was somewhat attenuated in those study groups jogging, with this "buffering" effect reaching statistical significance in women (p = 0.050). We conclude from this training study with normal subjects that regular jogging of approximately 10 to 15 km/week may help to diminish the deterioration of mood observed during winter months (e.g. increase in depressiveness), especially in women. Hereby, a training-induced increase in endurance capacity is apparently not a prerequisite for this long-term mental effect of jogging.

Air pollution and diseases of the respiratory tracts in pre-school children: A transfer function model.

The purpose of the present statistical analysis was the assessment of the relation between time series of environmental factors and of frequencies of diseases of the respiratory system in pre-school children. During about one year, daily measurements of air pollutants and climatic variables were taken. During the same period of time two series of medical data were collected: (i) The daily relative number of pre-school children, exhibiting diseases of the respiratory tracts who either came to the outpatients' clinic of the children's hospital or were reported by paediatricians in Basle (ENTRIES). (ii) The daily relative frequency of symptoms of the respiratory tracts observed in a group of randomly selected pre-school children (SYMPTOMS).By means of transfer function models the relation between the two target variables and the 'explaining' variables was analysed. Several practical problems did arise: Choice of the appropriate transformation of the different series, interpretation of the crosscorrelation function using different methods of 'prewhitening', time splitting and nonstationarity of the crosscorrelation structure. In particular, it was found that after prewhitening the crosscorrelation function between the explanatory series SO2 and the response series SYMPTOMS changes with time. While during the 'winter period' an instantaneous relation between these two series (and to a lesser extent between NO2 and SYMPTOMS) was identified, no such relation was found for the other seasons.

Effects of self-monitored jogging on physical fitness, blood pressure and serum lipids: a controlled study in sedentary middle-aged men.

To study the effects of long-term, home-based exercise on physical fitness and cardiovascular risk factors of middle-aged nonsmoking males, a controlled study was conducted in 61 sedentary Swiss men. Thirty-nine men were randomly allocated to jog 2 h/week for 4 months on an individually prescribed and heart-rate-controlled basis, whereas 22 men served as controls. Despite varying adherence to the exercise regimen, the 4-month net change (effect in exercise group minus effect in control group) in estimated endurance capacity was significant and positive. Net changes in arterial blood pressure, measured with a random-zero device, were nonsignificant, but after exclusion of low-normotensive men (n = 19) from analysis, a significant net effect of exercise on diastolic blood pressure was seen (-4.3 mmHg; p = .048). The following net changes in serum lipid levels occurred: HDL cholesterol + 0.12 mmol/l (p = .028), total triglycerides -0.21 mmol/l (ns), HDL-C/total cholesterol ratio +0.02 (p = .047). Exploratory analyses revealed that an increase in estimated endurance capacity was associated with a rise in systolic and diastolic blood pressure (r = 0.49 and 0.43, respectively; p less than 0.01 both). Changes in the waist-hip ratio were directly related to the change in diastolic blood pressure (r = 0.27; p less than 0.05). Multivariable analysis indicated that much of the beneficial effect of exercise on diastolic blood pressure was apparently mediated through a decrease in body fat. This study confirms that individually prescribed jogging can reduce cardiovascular risk factors in self-selected nonsmoking males.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of long-term, self-monitored exercise on the serum lipoprotein and apolipoprotein profile in middle-aged men.

To study the effects of long-term, self-monitored exercise on the serum lipid profile and body composition of middle-aged non-smoking males, a controlled study was conducted in 61 sedentary, middle-class Swiss men. Thirty-nine men were randomly allocated to jog 2 h/wk for 4 months on an individually prescribed, heart rate-controlled basis, whereas 22 men served as controls. Despite varying adherence to the exercise regimen, the following 4-month net changes (effect in exercise group minus effect in control group) in lipids were seen: HDL cholesterol (C) +0.12 mmol/l (95% CI 0.02, 0.22; P = 0.028), LDL-C +0.08 mmol/l (ns), VLDL-C -0.26 mmol/l (-0.45, -0.07; P = 0.009), total triglycerides (TT) -0.21 mmol/l (ns), HDL-C/total C +0.02 (0.001, 0.05; P = 0.047). The net changes in endurance capacity and resting heart rate in favour of exercisers were significant as well, whereas no significant changes in apolipoprotein levels were seen. Exploratory analyses revealed, for example, associations of the increase in total physical activity with an increase in the HDL-C/total C ratio (r = 0.46; P less than 0.001), and of the change in estimated body fat content with an opposed change in the HDL-C/total C ratio (r = -0.40; P less than 0.001), or an inverse relationship of the change in subcutaneous fat with a change in the HDL2-C level (r = -0.39; P less than 0.001). Multivariable regression analysis suggested that much of the effect of jogging on HDL-C was apparently mediated through a decrease in body fat content. A change in the waist/hip ratio was unrelated to lipoprotein changes but was related to the change of TT level (r = 0.22; P less than 0.05). This study confirms that individually prescribed, unsupervised jogging can increase HDL-C levels and improve the serum lipoprotein profile in self-selected nonsmoking males. Although the effect is modest, it may be relevant to preventive cardiology, given the evidence for a reduction in cardiovascular risk even after apparently small decreases in risk factor levels.

Significant association between outdoor NO2 and respiratory symptoms in preschool children.

A study of 1225 preschool children was conducted in four regions of Switzerland with different levels of air pollution to investigate the relationship between air pollution and respiratory symptoms. Daily symptoms were recorded by parents on a diary form and air pollution exposure assessed by personal NO2 samplers. Each family participated for 6 weeks and personal samplers were changed every week. The frequency of respiratory symptoms per child and day was found to increase with increasing levels of NO2 measured outdoors. This relationship remained significant in a multiple regression model in which the factors smoking, origin, indoor air pollution, age and sex, season, and parents appreciation of air pollution at the living site were taken into account.

[Effects of air pollutants on the respiratory system in young children]. / Auswirkungen von Luftschadstoffen auf die Atemwege von Kleinkindern.

A one year study on a random sample of 1225 Swiss children aged 0-5 years was conducted in four different areas (two urban, one suburban and one rural) of Switzerland to investigate the relationship between air pollution and respiratory symptoms. For each child daily symptoms over a six week period were recorded by their parents in the form of a standard diary and air pollution was assessed by personal NO2-samplers. 20% of the diaries were validated by comparison with the attending pediatrician's case-notes and showed good agreement (87%). The frequency of respiratory symptoms per child per day was found to increase with increasing levels of NO2 measured outdoors, but not with NO2 concentration indoors (when other indoor sources for NO2 where present). Possible other factors were accounted for by multiple regression analysis and the variables "season" and "child's susceptibility to colds" also showed a significant association with respiratory symptoms. But the relationship between NO2 outdoors and respiratory symptoms per child per day remained statistically significant. The multiple regression model explains 7% of the total variability. The result indicates that air pollution is a contributory factor in the development of respiratory symptoms in children.

Anthropometric and lifestyle correlates of serum lipoprotein and apolipoprotein levels among normal non-smoking men and women.

The relationship between serologic predictors of coronary risk and anthropometric as well as lifestyle characteristics was investigated in 61 men (37.5 +/- 8.5 yrs) and 33 women (40.1 +/- 9.0 yrs). All subjects were healthy non-smokers, mostly middle-class bank employees. In bivariate analysis, among both genders the ratio of waist-to-hip circumference (WHR) was the single best predictor of levels of serum LDL-cholesterol, apolipoprotein B, VLDL-cholesterol and triglycerides (positive association) as well as HDL-cholesterol and apolipoprotein A-I (inverse association). In men, body fat as estimated from bioelectrical impedance measurement was the second best predictor of lipoprotein and apoprotein concentrations, whereas in women it was the body mass index (BMI). The additional independent predictive power of WHR and body fat for the lipid profile was tested in multivariate analysis by adding WHR and body fat sequentially to regression models containing already BMI, endurance capacity, exercise, alcohol consumption and age. For example, explained variance of triglyceride distribution rose from 26.3 to 35.1% (P = 0.01 for increase) when body fat was entered into the regression equation, or inclusion of WHR into a model already containing age, the behavioral variables, BMI, and body fat increased the explained variance of LDL/HDL-cholesterol ratio from 20.9 to 27.6% (P = 0.04 for increase). In women, the same regression models were even slightly more predictive for the serum lipid profile. Endurance capacity was related to a low atherogenic risk lipid profile in bivariate analysis but lost much of its predictive power in multivariate analysis, which confirms that the effect of fitness on lipid levels is probably mediated in part by a low body fat content. It is concluded from this cross-sectional investigation that studies which focus on associations between lifestyle and serologic predictors of atherogenic risk should possibly include the WHR and a measure of body fat, since the latter two appear to be closer correlates of serum lipoprotein and apolipoprotein levels than BMI or single behavioral factors, at least among male non-smokers.