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Biomedical subjects

H E Wichmann

Publications and source records attributed to H E Wichmann.

At least 127 records · Page 7Linked to original sources
PubMed1997

[Normal values for spirometry lung function values and peak flow for 7-18-year-old probands].

A prospective cohort study, designed to examine the long-term effects of air pollution on respiratory health, was conducted during the years 1977, 1979 and 1985 in Southwest Germany. In order to derive prediction equations, we analyzed the functional relationship of pulmonary function and anthropometric measures by graphical tools and regression analysis. Results are based on 10.605 spirometric measurements from 6625 individuals aged 7 to 18 years. Asthmatics, extremely overweighted persons, and smokers were excluded. Regression equations for the logarithmic transformation of FVC, FEV0.75 FEV1.0 MMEF and peak-flow are obtained separately for boys and girls, using the logarithms of standing height, weight and age as linear predictors. A comparison between equations from the present study and other available reference data shows that our prediction values for the volume parameters are at the upper end of the range given by other studies whereas for the flow parameters they lie in the middle of the range.

Adolescent↗
PubMed1997

Short-term effects of particulate air pollution on respiratory morbidity in asthmatic children.

Short-term effects of air pollution (consisting primarily of sulphur dioxide and particulate matter but with low acidity) on respiratory morbidity were studied in asthmatic children from Sokolov, Czech Republic. Eighty nine children with asthma, who recorded daily peak expiratory flow measurements, symptoms and medication use in a diary, were analysed for 7 months during the winter of 1991-1992. Air pollution measurements included: SO2, total suspended particulates (TSPs), inhalable particles, ie. particulate matter of aerodynamic diameter < or = 10 microm, particle strong acidity (PSA) and fine particle sulphate concentration (SO4). Linear and logistic regression analyses estimated the impact of air pollutants adjusted for trend, temperature and weekend and autocorrelated errors. Exposure to elevated levels of air pollution was associated with decreased peak expiratory flow rates, increased respiratory symptoms, increased prevalence of school absence and fever, and increased medication use. Prolonged exposure to particle SO4 showed the largest effect estimates. At the end of January, an air pollution episode occurred, during which respiratory symptoms, prevalence of fever, school absence and asthma medication increased. The association between respiratory symptoms and particulate SO4 was highly dependent on this episode, whilst the associations between lung function and SO4 as well as between fever and SO4 were still observed when this air pollution episode was excluded. Some evidence was found that exposure to air pollution might have enhanced the respiratory symptoms while children were experiencing respiratory infections. In this study, a panel of children with mild asthma experienced small decreases in peak expiratory flow and increased dyspnoea in association with fine particles formed during air pollution episodes.

Adolescent↗
PubMed1996

Acute health effects of exposure to high levels of air pollution in eastern Europe.

Acute effects of winter-type air pollution characterized by high levels of SO2, moderate levels of particles, and low acidity were studied. A panel of 155 asthmatic children and 102 adults with a history of asthma from the former German Democratic Republic cities of Erfurt and Welmar and from the Czech Republic city of Sokolov participated from September 1990 through June 1992. The panelists recorded daily symptoms, medication intake, and peak expiratory flow (PEF). Statistical analysis was based on linear regression of population-averaged time series controlling for trend, meteorology, and autocorrelation. A temporospatial time series approach was also applied to the data to eliminate possible confounding by some known or unknown variables that occurred simultaneously in two of the study areas. Weak same-day effects and a stronger cumulative effect of air pollution on children was observed both for PEF and for symptoms. PEF decreased -0.90% (-1.35 to -0.46%), and a symptom score increased 14.7% (0.8-28.6%) in association with an average increase of 128 micrograms/m3 SO2 over the previous 5 days. Effects on adults were smaller and less consistent. Morbidity of children was best predicted by SO2 and sulfate concentrations. The authors conclude that prolonged, high exposure to winter-type pollution was associated with small adverse health effects in asthmatics.

Adolescent↗
PubMed1996

Arsenic burden among children in industrial areas of eastern Germany.

The internal burden of arsenic among 5- to 14-year-old eastern German children in the heavily polluted areas of Hettstedt, a region of smelting and copper mining, and Bitterfeld, a center of chemical production and coal mining, was compared with that in a control area (Zerbst) by means of urinary arsenic concentrations in 1992-94. The unadjusted geometric mean among the 950 children was significantly higher in Hettstedt (5.1 micrograms/l; 95% C.I. 4.8-5.5) but not in Bitterfeld (4.3 micrograms/l; 95% C.I. 3.7-4.9) compared with the control area (4.0 micrograms/l; 95% C.I. 3.5-4.5). This difference persisted after adjustment for relevant confounders. Despite these regional differences, recent fish consumption was as strongly associated with urinary arsenic levels (42% increase, 95% C.I. 18-71%). Additionally, although the geometric mean among the children in Hettstedt (4.8 micrograms As/g creatinine; 95% C.I. 4.5-5.1) was higher than that found in an environmental survey of eastern German children (3.60 micrograms As/g creatinine; 95% C.I. 3.06-4.24), it was similar to that found among western German children (4.59 micrograms As/g creatinine; 95% C.I. 4.20-5.02). This suggests that the arsenic contamination in Hettstedt is not substantially increasing the internal burden of arsenic among children above that found in other German children.

Adolescent↗
PubMed1996

Model analysis of the contrasting effects of GM-CSF and G-CSF treatment on peripheral blood neutrophils observed in three patients with childhood-onset cyclic neutropenia.

Human cyclic neutropenia (CN) is a rare haematological disorder characterized by regular fluctuation in the serial count of blood neutrophils. The oscillations occur at subnormal levels with a stable 3-week period. To reduce the risk of serious infections during the severe neutropenic nadir phases (< 0.25 x 10(9) neutrophils/l) patients are usually treated with recombinant growth factors. Compared with G-CSF, which has been shown to enhance the amplitudes substantially, the response to GM-CSF is poor: neutrophil numbers are not amplified, the cycles remain unchanged or are dampened. However, two cases with a modest neutrophil increase have been reported in the literature. In a recently published clinical study the different effects of GM-CSF and G-CSF application have been investigated in the same patients. Based on a mathematical model of CN we previously proposed, the detailed neutrophil data measured in this study are analysed by simulation. The contrasting clinical results can be quantitatively explained by the model concept of regulatory control together with possible individual feedback defects, i.e. abnormally reduced mitotic responsiveness of granulopoietic progenitor cells to GM-CSF and G-CSF.

Cell Division↗
PubMed1996

Daily mortality and air pollutants: findings from Köln, Germany.

STUDY OBJECTIVE AND DESIGN: For the APHEA study, the short term effects of air pollutants on human health were investigated in a comparable way in various European cities. Daily mortality was used as one of the health effects indicators. This report aims to demonstrate the steps in epidemiological model building in this type of time series analysis aimed at detecting short term effects under a poisson distribution assumption and shows the tools for decision making. In addition, it assesses the impact of these steps on the pollution effect estimates. SETTING: Köln, Germany, is a city of one million inhabitants. It is densely populated with a warm, humid, unfavourable climate and a high traffic density. In previous studies, smog episodes were found to increase mortality and higher sulphur dioxide (SO2) levels were connected with increases in the number of episodes of croup. PARTICIPANTS, MATERIALS AND METHODS: Daily total mortality was obtained for 1975-85. SO2, total suspended particulates, and nitrogen dioxide (NO2) data were available from two to five stations for the city area, and size fractionated PM7 data from a neighbouring city. The main tools were time series plots of the raw data, predicted and residual data, the partial autocorrelation function and periodogram of the residuals, cross correlations of prefiltered series, plots of categorised influences, chi 2 statistics of influences and sensitivity analyses taking overdispersion and autocorrelation into account. RESULTS AND CONCLUSIONS: With regard to model building, it is concluded that seasonal and epidemic correction are the most important steps. The actual model chosen depends very much on the properties of the data set. For the pollution effect estimates, trend, season, and epidemic corrections are important to avoid overestimation of the effect, while an appropriate short term meterology influence correction model may actually prevent underestimation. When the model leaves very little over-dispersion and autocorrelation in the residuals, which indicates a good fit, correction for them has consequently little impact. Given the model, most of the range of SO2 values (5th centile to 95th centile) led to a 3-4% increase in mortality (significant), particulates led to a 2% increase (borderline significant, less data than for SO2), and NO2 had no relationship with mortality (measurements possibly not representative of actual exposure). Effects were usually delayed by a day.

Air Pollutants↗
PubMed1996

Prevalence of respiratory symptoms, bronchial hyperresponsiveness and atopy among adults: west and east Germany.

The prevalence of respiratory symptoms, atopic sensitization and bronchial hyperresponsiveness was compared in a random sample of adults, 20-44 yrs of age, in two cities in West and East Germany, Hamburg and Erfurt, respectively. There were much higher levels of outdoor air pollution due to sulphur dioxide and suspended particulates in Erfurt, and major differences in living conditions during the last 40 yrs. Within the European Respiratory Health Survey, a short questionnaire was answered by 3,156 (80% response rate) subjects in Hamburg and 3,272 (74%) in Erfurt. A subset of responders to the short questionnaire completed a long questionnaire, spirometry, methacholine or bronchodilator test, skin test, and total and specific immunoglobulin E (IgE) measurements, with a total number of 1,159 participants in Hamburg and 731 in Erfurt. Six out of 8 questions on respiratory symptoms and diagnoses were answered in the affirmative more frequently in Hamburg than in Erfurt. In Hamburg, mean forced expiratory volume in one second (FEV1)% of predicted was 105 vs 107% in Erfurt (p < 0.0001), and bronchial hyperresponsiveness was more frequently observed in Hamburg than in Erfurt (25 vs 19%; p < 0.05). Atopic sensitization was more prevalent in Hamburg than in Erfurt regarding the results of skin tests against grass pollen (24 vs 19%; p < 0.05), birch pollen (19 vs 8%; p < 0.0005), cat (10 vs 2%; p < 0.0005), and Dermatophagoides pteronyssinus (14 vs 10%; p < 0.05). This was reflected by the prevalences of positive specific IgE values, which were higher in Hamburg than in Erfurt for grass (26 vs 20%; p < 0.05), birch (20 vs 10%; p < 0.0005) and cat (12 vs 8%; p < 0.05). In Hamburg, compared to Erfurt, there was: a lower mean number of siblings (p < 0.005); a higher degree of childhood and current exposure to environmental tobacco smoke (p < 0.005); and a higher frequency of fitted carpets and reported mould or mildew inside the house (p < 0.005). Therefore, these data may support the hypothesis that childhood factors and exposure to indoor allergens and irritants may have been more relevant for the development of asthma and atopy than the potential long-term exposure to high concentrations of sulphur dioxide and particulate matter.

Adult↗
PubMed1995

Lung cancer deaths attributable to indoor radon exposure in West Germany.

BACKGROUND: There is substantial epidemiological and experimental evidence that exposure to radon at levels found in underground mines can cause lung cancer. Although radon levels measured in homes are normally substantially lower, there is concern about the presence of a known lung carcinogen in a residential setting. METHODS: Using national survey data on radon concentrations in homes in the former West Germany, the proportion and absolute numbers of lung cancer deaths attributable to radon are estimated. As lung cancer risk models derived directly from residential radon studies are not yet available, the risk model developed recently by Lubin et al. from a joint analysis of 11 underground miners' studies is applied. For an estimate of the impact of smoking on radon-attributable lung cancers, three different approaches are used and compared. RESULTS: Our analysis shows that after adjusting for dosimetry differences between mines and homes about 7% of all lung cancer deaths in the western part of Germany may be due to residential radon. This corresponds to a total of about 2000 deaths (95% CI: 500-8200), 400 in females and 1600 in males. Adjusting for the intermediate relationship for smoking and radon, the attributable risk is estimated to be about 4-7% for smokers and 14-22% in non-smokers. CONCLUSIONS: Our analysis basically confirms the results of former calculations with regard to the total number of lung cancer deaths attributable to radon in West Germany. However, we show that the standard practice that applies the same model to smokers and non-smokers may result in biased estimates for these groups.

Air Pollution, Indoor↗
PubMed1995

The effect of continuous G-CSF application in human cyclic neutropenia: a model analysis.

Human cyclic neutropenia (CN) is a rare haematological disorder characterized by oscillations of blood neutrophils at subnormal levels with a stable period of approximately 21 d. During the phase of severe neutropenia (neutrophils < 250 cells/microliters), which last 4-10 d, the patients are endangered by serious infections. Several authors report that continuous G-CSF application can elevate the blood neutrophils to such a level that the risk of infections is significantly reduced. Although the characteristic cycles are not eliminated by G-CSF, the period of the oscillations is shortened to 12-14 d. Based on a previously proposed computer-simulation model of human CN, the effects of continuous G-CSF application on CN are studied. It is shown how the known different cell-kinetic effects of G-CSF on granulopoiesis explain the clinical data in CN. The reduced length of the cycles emerges as a result of the transit time reduction of the post-mitotic granulopoietic cells by G-CSF. The measured increase of the neutrophil maxima is reproduced by the additional mitoses of the immature granulopoietic bone marrow cells induced by G-CSF. The slight elevation of the neutrophil nadirs can be attributed to a weak effect of G-CSF on the assumed underlying defect in CN (an abnormally small variance of the granulopoietic bone-marrow transit time).

Cell Cycle↗
PubMed1995

Collaborative study on the genetics of asthma in Germany.

In several clinical centres in Germany (Berlin, Hamburg, Munich and others) a collaborative study on the genetics of asthma is being performed. It started at the beginning of 1995, when 100 nuclear families with two or more affected siblings were recruited. The participants are being characterized by interview information, methacholine challenge, peak flow variability, skin-prick test, total and specific IgE.

Adolescent↗
PubMed1995

Measurement of acidic aerosol species in eastern Europe: implications for air pollution epidemiology.

A large number of studies have indicated associations between particulate air pollution and adverse health outcomes. Wintertime air pollution in particular has been associated with increased mortality. Identification of causal constituents of inhalable particulate matter has been elusive, although one candidate has been the acidity of the aerosol. Here we report measurements of acidic aerosol species made for approximately 1.5 years in Erfurt, Germany, and Sokolov, Czech Republic. In both locations, the burning of high-sulfur coal is the primary source of ambient air pollution. Twenty-four-hour average measurements were made for PM10, [particulate matter with an aerodynamic diameter (da) < or = 10 microns], as well as fine particle (da < 2.5 microns) H+ and SO4(2-) for the entire study. Additionally, separate day and night measurements of fine particle H+, SO4(2-), NO3-, and NH4+ and the gases, SO2, HNO3, HONO, and NH3 were collected with an annular denuder/filter pack system over a 7-month (late winter-summer) period with additional measurements during pollution episodes the following winter. At both sites, 24-hr SO2 (mean concentrations of 52 micrograms/m3, with peak levels of > 585 micrograms/m3) and PM10 (mean concentration 60 micrograms m3) concentrations were quite high. However, aerosol SO4(2-) concentrations (mean concentration of approximately 10 micrograms/m3) were not as great as expected given the high SO2 concentrations, and acidity was very low (mean concentration of < 1 microgram/m3, with peak levels of only 7 micrograms/m3). Low acidity is likely to be the result of NH3 neutralization and slow conversion of SO2 to SO4(2-).(ABSTRACT TRUNCATED AT 250 WORDS)

Acids↗
PubMed1995

Health effects of high level exposure to traditional pollutants in East Germany--review and ongoing research.

In East Germany ambient air pollution is characterized by high concentrations of sulfur dioxide (SO2) and suspended particulates (SP). Since acidity and sulfate are surprisingly low, oxidation of SO2 seems to be incomplete and neutralization seems to play an important role. Few studies on health effects of air pollution in the former German Democratic Republic have been performed. They showed an increased prevalence in polluted areas of respiratory symptoms, lung function decrement, mild anemia, nonspecific stimulation of the immune system and, retardation of skeletal maturation of children. Since the German unification in 1990, several large-scale studies have been started. Short-term effects of air pollution on daily mortality have been investigated in Erfurt retrospectively for 1980 to 1989. Logarithmic exposure-effect curves have been found for both SO2 and SP. The number of deaths increased by about 10% with SO2 and by more than 20% with SP if the 95th percentile of the pollutant is compared to the 5th percentile. The logarithmic shape shows that the increase of ambient concentrations at the beginning of the heating season in fall is more important than further increases in concentrations later in winter. A second study on short-term effects was conducted using daily peak flow measurements and respiratory symptoms in 270 patients with asthma and other obstructive airway diseases in East Germany and the Czech Republic between 1990 and 1992. From regression analysis it follows that an increase by 500 micrograms/m3 of SO2 leads to a mean decrease of the average patient's peak flow below 2%.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1995

[Cohort study of respiratory diseases and lung function in school children in Southwest Germany. 4. Inner city environment influences on respiratory diseases in Mannheim].

A prospective cohort study on more than 8000 schoolchildren aged 8 to 16 years was conducted during the years 1977, 1979 and 1985 in Southwest Germany. The primary question of the study was to investigate the regional differences in respiratory health status of the children due to air pollution. In a logistic regression analysis of 11 respiratory symptoms and 2 scores measuring the tendency to infectious and asthmatic diseases we found increased odds ratios for respiratory symptoms for children living in Mannheim or the Breisgau compared to those living in the Black Forest. The regional effects were highest in the population of children aged 8-10 years and disappeared for the 16 years old adolescents. The relative risks of infectious respiratory symptoms agree spatially and temporarily well with the pattern of SO2 concentration which may be interpreted as an indicator for air pollution by power plants, industry and domestic heating. In this part of the analysis we investigate the increased prevalences of symptoms and diseases with respect to exposure related to small areas within the city of Mannheim. To classify the personal exposure we use emission data related to areas and main roads and emission data on the level of square kilometers which are connected with the health data by the children's home address. Symptoms and diseases are analysed by logistic regression and the results depend on data of those children who had lived for at least 5 years in the same area (n77 = 1146, n79 = 1140, n85 = 1128). After allowing for the effects of relevant covariables an association of the prevalence of respiratory and asthmatic illness to exposure due to automobile exhaust (traffic density, NO2 and soot), SO2 or ozone was not seen. Thus no evidence was found to suggest that there is a relationship between the spatial pattern of exposure data and the pattern of respiratory symptoms for children living in Mannheim.

Adolescent↗
PubMed1994

Indoor factors and IgE levels in children.

The objective of the study was to determine indoor characteristics of households in relation to total serum IgE. In a population-based cross-sectional study, 1096 6-12-year-old children were examined in three East German towns (Eisleben, Hettstedt, and Zerbst). Of the questionnaires, 772 (70.4%) were returned by the parents. Serum IgE of 703 children and urinary cotinine in a random subsample of 224 children were analyzed. Linear regression on log(IgE) adjusted for the main covariates was used to assess indoor risk factors such as room size, and the presence of curtains, carpet, and plants in the child's room. Open-heating facilities indoors, passive smoking, and furniture made of chipboard had the most important effect. A higher urinary cotinine/creatinine ratio was associated with higher total IgE level. Total IGE increased also with the number of persons living in the household, independently of indoor smoking. We conclude that indoor air pollution from smoking and open-heating facilities may increase the IgE levels of children. The role of other factors such as chipboard, which could reflect the emission of formaldehyde, or the number of persons per household, which could reflect viral or helminthic infection, remains to be analyzed.

Air Pollution, Indoor↗
PubMed1994

Detection of early lung impairment with aerosol bolus dispersion.

The broadening of inhaled aerosol boluses (aerosol bolus dispersion) during respiration provides a noninvasive measure of convective gas mixing in the lungs. In this study, the sensitivity and specificity of this technique for the diagnosis of early lung impairment due to cigarette smoking was evaluated. Two hundred and sixteen randomly selected subjects (126 smokers and 90 nonsmokers) were investigated with aerosol dispersion in comparison to conventional lung function tests. The cumulative cigarette consumption of the subjects was quantified by "pack-years" (PY). Smokers were classified into the following groups: 0 < PY < or = 10; 10 < PY < or = 20; 20 < PY < or = 30; and PY > 30. Forced expiratory volume in one second (FEV1), maximal expiratory flow at 25, 50 and 75% vital capacity (MEF25, MEF50 and MEF75) decreased significantly with increasing cigarette consumption. In comparison to nonsmokers, FEV1 was significantly reduced in smokers of 10 < PY < or = 30, and MEF75 was significantly reduced in smokers of PY > 20. Aerosol bolus dispersion increased with increasing PY. For all groups of smokers, even those with PY < 10, bolus dispersion was significantly increased in comparison to lifelong nonsmokers, indicating alterations in convective gas mixing in the lungs. Calculation of receiver operating characteristics for the lung function parameters under consideration showed that bolus dispersion has a higher sensitivity and specificity than conventional lung function parameters. Hence, the aerosol bolus dispersion test could be a promising epidemiological tool to study early abnormalities in intrapulmonary gas mixing due to environmental factors.

Adult↗
PubMed1994

[Cohort study of respiratory tract diseases and lung function in school children in southwest Germany. 2. Regional influences on respiratory tract diseases in Mannheim and the Freiburg area].

A prospective cohort study on 8124 schoolchildren aged 8 to 16 was conducted during the years 1977, 1979 and 1985 in Mannheim and two regions near Freiburg (Breisgau and the Black Forest). The objective of this part of the analysis was to investigate the regional differences in respiratory symptoms due to air pollution. Results are presented of 5726 children who had been living in those regions for at least five years at the times of interview. We have analysed 11 respiratory symptoms and two scores, measuring the tendency to infectious and asthmatic diseases, by logistic regression. Comparing the children living 1977 in Mannheim or the Breisgau to those living in the Black Forest the Relative Risks (Odds Ratios) of respiratory symptoms are in the range of 1.26-1.85 and 1.21-1.96 respectively. The results for the year 1979 are similar. In 1985 the regional effect has become smaller and no difference can be observed between Breisgau and the Black Forest. The infect score comprises bronchitis, inflamed throat with fever and sinusitis. The Relative Risk of an increased score decreases from 1.67 in 1977 to 1.65 in 1979 and 1.35 in 1985 in Mannheim and from 1.40 to 1.28 and 1.05 respectively in the Breisgau. The results of asthma and asthma symptoms are not homogeneous. In the Breisgau 1977 and 1979 the Relative Risk of an increased asthma score is slightly higher compared to the Black Forest. Allergies of the skin are reported more often in Mannheim than in the other areas. The Relative Risks of infectious respiratory symptoms and diseases agree spatially and temporarily well with the pattern of SO2 concentration. SO2 may be interpreted as an indicator for air pollution by power plants, industry and domestic heating.

Adolescent↗
PubMed1993

Air pollution and daily mortality in Erfurt, east Germany, 1980-1989.

In Erfurt, Germany, unfavorable geography and emissions from coal burning lead to very high ambient pollution (up to about 4000 micrograms/m3 SO2 in 1980-89). To assess possible health effects of these exposures, total daily mortality was obtained for this same period. A multivariate model was fitted, including corrections for long-term fluctuations, influenza epidemics, and meterology, before analyzing the effect of pollution. The best fit for pollution was obtained for log (SO2 daily mean) with a lag of 2 days. Daily mortality increased by 10% for an increase in SO2 from 23 to 929 micrograms/m3 (5% quantile to 95% quantile). A harvesting effect (fewer people die on a given day if more deaths occurred in the last 15 days) may modify this by +/- 2%. The effect for particulates (SP, 1988-89 only) was stronger than the effect of SO2. Log SP (daily mean) increasing from 15 micrograms/m3 to 331 micrograms/m3 (5% quantile to 95% quantile) was associated with a 22% increase in mortality. Depending on harvesting, the observable effect may lie between 14% and 27%. There is no indication of a threshold or synergism. The effects of air pollution are smaller than the effects of influenza epidemics and are of the same size as meterologic effects. The results for the lower end of the dose range are in agreement with linear models fitted in studies of moderate air pollution and episode studies.

Air Pollutants↗