Biomedical subjects

Lothar Kreienbrock

Publications and source records attributed to Lothar Kreienbrock.

16 recordsLinked to original sources

PubMed2006

Shiga toxin-producing Escherichia coli infection in Germany: different risk factors for different age groups.

The authors conducted a matched case-control study in Germany to identify risk factors for sporadic illness associated with Shiga toxin-producing Escherichia coli (STEC) infection, regardless of serogroup. From April 2001 through March 2003, cases were prospectively enrolled through a laboratory-based sentinel surveillance system located in 14 of the 16 German federal states. One control was identified per case, matched by age and region. Conditional logistic regression was used in the analysis, which was conducted separately for three age groups (<3 years, 3-9 years, and > or =10 years). The median age of the 202 enrolled cases was 2.5 years (range, 3 months-89 years). Hemolytic uremic syndrome developed in five patients. Non-O157 strains accounted for 85% of the isolated STEC. In children under 3 years of age, having touched a ruminant had the highest odds of disease, and raw milk was the only food identified as a risk factor. In contrast, in persons aged 10 years or older, only food items (i.e., lamb meat, raw spreadable sausages) were significantly associated with illness. In this study, risk factors were age-specific. Direct transmission through food played a lesser role in children under 3 years of age, the population at greatest risk of both acquiring STEC infection and developing hemolytic uremic syndrome.

Adolescent↗

PubMed2006

Canine microglial cells: stereotypy in immunophenotype and specificity in function?

Microglial cells represent the endogenous immune system of the central nervous system (CNS). Upon pathological insults they reveal their immunological potential aimed at regaining homeostasis. These reactions have long been believed to follow a uniform and unspecific pattern which is irrespective to the underlying disease entity. Evidence is growing that this view seriously underrates microglial competence as the defenders of the CNS. In the present study, microglial cells of 47 dogs were examined ex vivo by means of flow cytometry. Ex vivo examination included immunophenotypic characterization using eight different surface markers and functional studies such as phagocytosis assay and the reactive oxygen species (ROS) generation test. The dogs were classified according to their histopathological diagnoses in disease categories (controls, canine distemper virus (CDV) induced demyelination, other diseases of the CNS) and results of microglial reaction profiles were compared. Immunophenotypic characterization generally revealed relative high conformity in the microglial disease response among the different groups, however the functional response was shown to be more specific. Dogs with intracranial inflammation and dogs with demyelination showed an enhanced phagocytosis, whereas a significant up-regulation of ROS generation was found in dogs with demyelination due to CDV infection. This strongly suggests a specific response of microglia to infection with CDV in the settings of our study and underlines the pivotal role of microglial ROS generation in the pathogenesis of demyelinating diseases, such as canine distemper.

Animals↗

PubMed2006

Impact of measurement error in exposures in german radon studies.

Case-control studies on lung cancer and residential radon exposure were conducted in West and East Germany. Odds ratio (OR) estimates from primary analysis are now subject to correction for measurement error in exposure. We apply the regression calibration method adopting a bivariate multiplicative error model of the classical type; that is, we investigate the impact of errors in the exposure of primary interest, radon, and of errors in the most potent confounder, smoking. The OR estimates per 100 Bq/m3 are throughout higher after correcting for errors in radon exposure (e.g., 1.02 and 1.11 for the West and the East German study, respectively, corrected for an error of size 0.4); ignoring the clear but small correlation between radon exposure and smoking of about -0.06 would lead to less conservative corrections (1.10 and 1.13 for West and East, respectively). Accounting for a realistically sized error in the smoking variable additionally increases the OR estimates slightly. Remarkable is the fact that the naive OR estimate of the West study of 0.97 exceeds unity after correcting for errors in radon exposure larger than 0.3. We conclude that correcting for errors in radon exposure has a meaningful impact on OR estimates, that the correlation between radon exposure and the smoking variable affects the correction even if the smoking variable was error-free, and that such an analysis is extremely valuable to grasp an important issue in epidemiology, that is, the dimension of residual confounding due to adjusting for an imprecisely measured smoking variable.

Air Pollutants, Radioactive↗

PubMed2006

Lung cancer risk among former uranium miners of the WISMUT Company in Germany.

UNLABELLED: After 1946, the WISMUT Company developed the third-largest uranium-mining province in the world in the German Democratic Republic. METHODS: A case-control study among former WISMUT miners was conducted to investigate the lung cancer risk in relation to attained age, time since exposure, exposure duration, and exposure rate. It consisted of 505 patients with lung cancer and 1,073 controls matched to cases according to the year of birth. The cumulative exposure to radon and radon decay products was calculated as the sum of yearly exposures and expressed in Working Level Months (WLM). Cases had a mean cumulative exposure of 552 WLM compared to 420 WLM in controls. RESULTS: There was a statistically significant increase in lung cancer risk for cumulative exposures above 800 WLM. Under the assumption of a linear risk model, there was a significant increase in the relative risk of 0.10 per 100 WLM after adjusting for smoking and asbestos exposure. For current smokers the increase in relative risk was lower (0.05 per 100 WLM), whereas it was higher (0.20 per 100 WLM) among nonsmokers and longtime ex-smokers. After correcting in a sensitivity analysis for the fact that the controls of this study had a higher average exposure than the population of WISMUT workers they were recruited from, the adjusted ERR increased to 0.24 per 100 WLM. Lung cancer risk declined with time since exposure, except for exposures received 45 or more years ago. No inverse dose rate effect was observed.

Aged↗

PubMed2006

Residential radon and lung cancer--detailed results of a collaborative analysis of individual data on 7148 persons with lung cancer and 14,208 persons without lung cancer from 13 epidemiologic studies in Europe.

OBJECTIVES: Studies seeking direct estimates of the lung cancer risk associated with residential radon exposure lasting several decades have been conducted in many European countries. Individually these studies have not been large enough to assess moderate risks reliably. Therefore data from all 13 European studies of residential radon and lung cancer satisfying certain prespecified criteria have been brought together and analyzed. METHODS: Data were available for 7148 persons with lung cancer and 14,208 controls, all with individual smoking histories and residential radon histories determined by long-term radon gas measurements. RESULTS: The excess relative risk of lung cancer per 100 Bq/m3 increase in the observed radon concentration was 0.08 [95% confidence interval (95% CI) 0.03-0.16; P=0.0007] after control for confounding. The dose-response relationship was linear with no evidence of a threshold, and it remained significant when only persons with observed radon concentrations of <200 Bq/m3 were included. There was no evidence that the excess relative risk varied with age, sex, or smoking history. Removing the bias induced by random uncertainties related to radon exposure assessment increased the excess relative risk of lung cancer to 0.16 (95% CI 0.05-0.31) per 100 Bq/m3. With this correction, estimated risks at 0, 100, and 400 Bq/m3, relative to lifelong nonsmokers with no radon exposure, were 1.0, 1.2, and 1.6 for lifelong nonsmokers and 25.8, 29.9, and 42.3 for continuing smokers of 15-24 cigarettes/day. CONCLUSIONS: These data provide firm evidence that residential radon acts as a cause of lung cancer in the general population. They provide a solid basis for the formulation of policies with which to manage risk from radon and reduce deaths from the most common fatal cancer in Europe.

Case-Control Studies↗

PubMed2005

Increased lung cancer risk due to residential radon in a pooled and extended analysis of studies in Germany.

Residential radon has been shown to be a risk factor for lung cancer in several studies-but with limited power in each single study. The data of two case-control studies performed during 1990-1997 in Germany and used for previous publications have been extended and pooled. Both studies have identical study designs. In total, data of 2,963 incident lung cancer cases and 4,232 population controls are analyzed here. One-year radon measurements were performed in houses occupied during the 5-35 y prior to the interview. Conditional logistic and linear relative risk regression was used for the analysis. Measurements covered on average 70% of the exposure time window, with an average radon exposure of 61 Bq m(-3). The smoking and asbestos-adjusted ORs were 0.97 [95% confidence interval (CI) 0.85 to 1.11] for 50-80 Bq m(-3), 1.06 (95% CI 0.87 to 1.30) for 80-140 Bq m(-3) and 1.40 (95% CI 1.03 to 1.89) for radon concentrations above 140 Bq m(-3), compared to the reference category <50 Bq m(-3). The linear increase in the odds ratio per 100 Bq m(-3) was 0.10 (95% CI -0.02 to 0.30) for all subjects and 0.14 (95% CI -0.03 to 0.55) for less mobile subjects who lived in only one home in the last 5-35 y. The risk coefficients generally were higher when measurement error in the radon concentrations was reduced by restricting the population. With respect to histopathology, the risk for small cell carcinoma was higher than for other subtypes. This analysis strengthens the evidence that residential radon is a relevant risk factor for lung cancer.

Adult↗

PubMed2003

Hormonal factors and risk of lung cancer among women?

BACKGROUND: Gender differences in the histological distribution of lung carcinoma and a possibly greater susceptibility of women than men to tobacco carcinogens, suggest a possible influence of sex-specific hormones. This study examines endocrine factors and risk of lung cancer among women by smoking status and histology. METHODS: We used data of a case-control study on lung cancer conducted from 1990 to 1996 in Germany, including 811 histologically confirmed female cases and 912 female population controls. Information on various menstrual and reproductive factors, use of oral contraceptives (OC), hormone replacement therapy (HRT), and smoking was gathered through personal interviews using a structured questionnaire. Odds ratios (OR) and 95% CI adjusted for age, region, smoking, and education were calculated via logistic regression. RESULTS: A reduction in lung cancer risk was observed with the use of OC (OR = 0.69; 95% CI: 0.51-0.92), but no trend in risk with increasing duration of use, age at first use, or calendar year of first use was present. A history of HRT was associated with a reduced risk (OR = 0.83; 95% CI: 0.64-1.09), particularly after long duration (>/=7 years) (OR = 0.59; 95% CI: 0.37-0.93). No clear association was found with regard to age at menarche, length of menstrual cycle, number of live-births, and age at menopause. Overall results did not differ much by histological cell subtype. The reduction in lung cancer risk associated with the use of exogenous hormones was primarily seen among smoking women. CONCLUSIONS: Our data provide evidence for a possible role of hormonal factors in the aetiology of lung cancer in women.

Adult↗

PubMed2003

Residential radon and risk of lung cancer in Eastern Germany.

BACKGROUND: There is suggestive evidence that residential radon increases lung cancer risk. To elucidate this association further, we conducted a case-control study in Thuringia and Saxony in Eastern Germany during 1990-1997. METHODS: Histologically confirmed lung cancer patients from hospitals and a random sample of population controls matched on age, sex and geographical area were personally interviewed with respect to residential history, smoking, and other risk factors. One-year radon measurements were performed in houses occupied during the 5-35 years prior to the interview. The final analysis included a total of 1,192 cases and 1,640 controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression. RESULTS: Measurements covered on average 72% of the exposure time window, with mean radon concentrations of 76 Bq/m3 among the cases and 74 Bq/m3 among the controls. The smoking- and asbestos-adjusted ORs for categories of radon (50-80, 80-140 and >140 Bq/m*3, compared with 0-50 Bq/m3) were 0.95 (CI = 0.77 to 1.18), 1.13 (CI = 0.86 to1.50) and 1.30 (CI = 0.88 to 1.93). The excess relative risk per 100 Bq/mł was 0.08 (CI = -0.03 to 0.20) for all subjects and 0.09 (CI = -0.06 to 0.27) for subjects with complete measurements for all 30 years. CONCLUSIONS: Our data indicate a small increase in lung cancer risk as a result of residential radon that is consistent with the findings of previous indoor radon and miner studies.

Aged↗

PubMed2002

Risk factors for lung cancer among nonsmoking women.

To evaluate risk factors for lung cancer in nonsmoking women, we used data of a case-control study conducted between 1991 and 1996 in Germany. A total of 234 female histologically confirmed lung cancer patients and 535 population controls who had never smoked more than 400 cigarettes in their lifetime were personally interviewed with respect to occupation, exposure to environmental tobacco smoke (ETS), family history of cancer, prior physician-diagnosed lung diseases or cancer and diet. One-year radon measurements in the last dwelling were performed. Odds ratios (OR) adjusted for age and region and 95% confidence intervals (CI) were calculated via logistic regression. When cumulative duration of exposure to ETS in hours was considered, the OR for high compared to not or low ETS exposed women was 2.62 (CI:1.35-5.06) for occupational exposure and OR=1.67 (CI:0.86-3.25) for spousal exposure, exhibiting a significant trend for ETS at work. Working more than 10 years in jobs or industries with known or suspected lung carcinogens was associated with OR=2.0 (CI:0.99-4.0). An elevated risk due to prior lung diseases was present for pneumonia (OR=1.6; CI:1.07-2.40) and tuberculosis (OR=1.6; CI:0.77-3.37). No significant increase in risk with increasing residential radon levels or with the presence of a family history of lung cancer was apparent. Protective effects were observed for high vs. low consumption of fresh vegetables (OR=0.5; CI:0.25-0.82) and cheese (OR=0.3, CI:0.21-0.55). ETS at work, occupational hazards and previous pneumonia may be risk factors for lung cancer in nonsmoking women, while a diet rich in fresh vegetables and cheese seems to be protective.

Aged↗

PubMed2002

Calculating sample size bounds for logistic regression.

The calculation of a study's required sample size is one of the most important aspects of the validity of an epidemiological study. Logistic regression often is used in modelling in epidemiology. A simplified method to calculate the sample size for the multiple logistic-regression model was proposed by Hsieh et al. [Stat. Med. 17 (1998) 1623]. The approach for estimating the sample size is described and then applied in the planning of an epidemiological cross-sectional study of the associations of different risk factors with Toxoplasma infection among pregnant women. Although the method demands some additional information which is often difficult to obtain, it is a very useful tool in veterinary epidemiology.

Animals↗

PubMedDate not supplied

[The occurrence of Echinococcus multilocularis in red foxes in lower Saxony: identification of a high risk area by spatial epidemiological cluster analysis].

There is considerable interest in the spatial distribution of Echinococcus multilocularis in red foxes (Vulpes vulpes L.), because this parasite causes the zoonoses of alveolar echinococcosis which is potentially of high fatality rate. High risk areas are known from France, Switzerland and the Swabian Alb in Germany for a long time. In this work, the spatial scan statistic is introduced as an instrument for identification and localisation of high risk areas, so called disease clusters in spatial epidemiology. The use of the spatial scan statistic along with data about the distribution of the parasite in 5365 red foxes in Lower Saxony, that were collected during 1991 to 1997, led to the identification of another high risk area. The relative risk for this disease cluster is approximated by RR = 5.03 (CI0.95(RR) = [4.27; 6.58]) for the period of 1991 to 1994 and by RR = 4.45 (CI0.95(RR) = [3.53; 5.59]) for the period of 1994 to 1997, respectively.

Animals↗

PubMedDate not supplied

["Risk analysis"].

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Animals↗

PubMedDate not supplied

[The use of macrolides, lincomycin and tiamulin as animal feed drugs for pigs in Schleswig-Holstein].

An evaluation of production orders for medicated feedingstuffs for pigs given in 1998 in Schleswig-Holstein showed macrolides, lincomycin and tiamulin as frequently used antibiotical ingredients. The presented study analyses the production orders which include macrolides, lincomycin or tiamulin in more detail. There were large deviations to the rules of good clinical practise for the use of antibiotics (2000). The applied dosage was often lower than suggested in the literature.

Animal Feed↗

PubMedDate not supplied

[The use of sulfonamides and sulfonamide/trimethoprim combinations as animal feed drugs for pigs in Schleswig-Holstein].

An evaluation of production orders for medicated feedingstuffs for pigs given in 1998 in Schleswig-Holstein showed sulphonamides and combinations of sulphonamides and trimethoprim as frequently used antibiotical ingredients. The presented study analyses the production orders which include sulphonamides and combinations of sulphonamides and trimethoprim in more detail. There were large deviations to the rules of good clinical practise for the use of antibiotics. The applied dosage was often lower than suggested in the literature.

Animal Feed↗

PubMedDate not supplied

[The use of aminoglycosides, colistin and beta-lactam antibiotics as animal feed drugs for pigs in Schleswig-Holstein].

An evaluation of production orders for medicated feedingstuffs for pigs given in 1998 in Schleswig-Holstein showed aminoglycosides, colistin and beta-lactam antibiotics as regularly used antibiotical ingredients. The presented study analyses the production orders which include these antibiotics more in detail particularly with regard to the prescribed dosages. In part, there were deviations to the rules of good clinical practise for the use of anitbiotics. The applied dosage of spectinomycin and apramycin was often lower than suggested in the literature. The low oral bioavailability of amoxicillin was not considered when using amoxicillin in medicated feedingstuffs.

Aminoglycosides↗

PubMedDate not supplied

[The effect of response behaviour on veterinary epidemiological studies--an analysis based on a cross-sectional study of livestock management of cattle farms in Lower Saxony].

Cross-sectional studies are used as an epidemiological instrument in several veterinary investigations. A common means of collecting information is the questionnaire, which is send to diagnostic units like farmers. A common fact is, that not all designated individuals take part. So it is to be clarified, if and in which concern this fact influences the results of an epidemiological study. Considering the example of a cross-sectional study in cattle farms this paper shows, that consistency of Responders and Non-Responders differs significantly. Technical measures to estimate this effect and consequences for the results are shown. Small and medium farms showed a different response rate than big farms before as well as after a mailed reminding letter. Considering the complete return period there was no significantly different response rate between farms of different sizes. Furthermore there are noticeable differences between Responders and Non-Responders concerning parameters like housing or use of commercial feedstuff. Therefore it is implicitly required to send a reminding letter and pursue Non-Responders in researches. Otherwise a biased sample collective is generated.

Agriculture↗