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Biomedical subjects

U Kaletsch

Publications and source records attributed to U Kaletsch.

At least 19 recordsLinked to original sources
PubMed2001

Risk factors for pediatric tumors of the central nervous system: results from a German population-based case-control study.

BACKGROUND: From 1993 to 1997 we conducted two population-based case-control studies on childhood cancer and a variety of potential risk factors in Germany. One case group involved children under the age of 15 years having a tumor of the central nervous system (CNS). PROCEDURE: For both studies, one conducted in the northwestern area of Germany, the other covering the whole of West Germany, incident cases were identified from the nationwide German Childhood Cancer Registry, and controls were randomly selected from complete population registration files. RESULTS: In total 466 pediatric CNS tumor cases and 2,458 controls were available for analyses. We observed only few positive associations, namely, between CNS tumors and low birth weight [<2,500 g; odds ratio (OR), 1.73; 95% confidence interval (CI), 1.06-2.84], between ependymoma and maternal smoking during pregnancy (>10 cigarettes per day: OR, 4.71; 95% CI, 1.69-13.1), and between astrocytoma and exposure to wood preservatives (OR, 1.91; 95% CI, 1.22-3.01). CNS tumors were not associated with high birth weight, duration of breast feeding, maternal age at time of delivery, duration of gestation, previous fetal losses, paternal smoking during pregnancy, maternal alcohol consumption, the child's exposure to pesticides, maternal diagnostic X-ray examinations during pregnancy, X-ray examinations of the child, or exposure to residential magnetic fields. CONCLUSIONS: Despite the large study population, we found only few factors that were associated with CNS tumors or one of the morphological subgroups. Therefore, our results suggest that aspects of the prenatal and neonatal period play only a minor role in the etiology of pediatric CNS tumors.

Adolescent↗
PubMed2001

High-birth weight and other risk factors for Wilms tumour: results of a population-based case-control study.

UNLABELLED: Wilms tumour, or nephroblastoma, is one of the childhood cancers included in two recent population-based case-control studies in West Germany. Altogether, 177 children under the age of 10 years with Wilms tumour diagnosed between 1988 and 1994 and 2006 control children sampled from population registration files participated. Information on potential risk factors was obtained from the parents using a questionnaire and by subsequent telephone interview. We found an association with a high birth weight >4000 g (odds ratio 1.58; 95% confidence interval 1.01-2.48), which was somewhat stronger for children aged 2 years or older. Findings for young maternal age at birth and certain parental occupationally related exposures were not reported by previous studies and thus may be chance findings. As opposed to previous studies, we failed to confirm associations with high parental age at birth, maternal coffee and tea consumption during pregnancy, and exposure to pesticides. CONCLUSION: Based on this large population-based case-control study, high birth weight may play a role in the aetiology of Wilms tumour, but many risk factors previously suggested are of less importance.

Alcohol Drinking↗
PubMed2001

Risk factors for neuroblastoma at different stages of disease. Results from a population-based case-control study in Germany.

Neuroblastoma is one of the childhood cancers included in two recent population-based case-control studies in West Germany. Altogether, 183 children under the age of 8 with neuroblastoma diagnosed in 1988-1994 and 1785 control children sampled from population registration files participated. Information on potential risk factors was obtained from the children's parents by a self-administered questionnaire and subsequent telephone interview. We observed positive associations with the use of oral contraceptives or other sex hormones during pregnancy (particularly with male offspring), a shorter gestational duration, lower birth weight, and maternal alcohol consumption during pregnancy. While the association with maternal use of oral contraceptives or sex hormones was strong for stages I/II (odds ratio 4.5, 95% confidence interval 1.2-16.5), the associations with shorter gestation duration (odds ratio 3.4, 95% confidence interval 1.7-6.7) as well as maternal alcohol consumption during pregnancy (>7 glasses/week odds ratio 5.2, 95% confidence interval 1.3-20.6) were observed only for the unfavourable advanced stages. It is notable that the associations in our study were either observed only for the advanced stages of disease or only for the less advanced stages, but not for both subgroups. This adds to evidence for the hypothesis that neuroblastoma consists of at least two distinct disease entities, which differ in clinical stage at the time of diagnosis.

Adult↗
PubMed2000

Leukemia and non-Hodgkin's lymphoma in childhood and exposure to pesticides: results of a register-based case-control study in Germany.

Previous studies have suggested an association between exposure to pesticides and different types of childhood cancer. This paper presents results from a population-based case-control interview study of parents of children less than 15 years of age, which was conducted in the states of West Germany from 1993 to 1997. Cases were 1,184 children with leukemia, 234 with non-Hodgkin's lymphoma, and 940 with a solid tumor; 2,588 controls were also included. Parental occupational exposures were found to be related to childhood cancer regardless of the time period of exposure and the type of cancer. This finding might partially be explained by different recall of past exposures by the parents of cases and controls. Residential use of insecticides was associated with childhood lymphoma: both extermination of insects by professional pest controllers (odds ratio (OR) = 2.6, 95% confidence interval (CI): 1.2, 5.7) and frequency of parental use of household insecticides (p for trend = 0.02) were significant risk factors for this diagnosis. The use of pesticides on farms was weakly related to childhood leukemia (OR = 1.5, 95% CI: 1.0, 2.2), while their use in gardens was not associated with childhood leukemia (OR = 1.0, 95% CI: 0.8, 1.2). The major strengths of this study were the population base and the large number of cases and controls included; a drawback was assessment of exposure on the basis of parental interviews. The data provide some evidence for an increased leukemia risk for children living on farms and for an association between use of household pesticides and risk of childhood leukemia or lymphoma.

Adolescent↗
PubMed2000

[Epidemiology of childhood brain tumors].

The German Childhood Cancer Registry (GCCR) was established in 1980. From 1980 to 1997 4,447 CNS tumours in children below 15 years of age have been reported to the registry. From 1988 to 1997 the average annual incidence was 2.5/100,000 children. This corresponds to 19.2% of the registered diseases. Compared with incidence rates reported from other developed countries one can estimate that there is about 25% underreporting of CNS tumours in the GCCR. This is in contrast to the relatively complete ascertainment of other childhood malignancies (above 95%). Based on 3012 incident cases from 1988 to 1997 the Kaplan-Meier-estimate of 5-year-survival probability is 65% for all CNS tumours and 54% for PNETs and gliomas. An active long-term-follow-up shows that 30% of 142 children with secondary neoplasms following primary lymphoid leukaemias developed a CNS tumour. Following any primary childhood malignancies 45 CNS tumours were recorded, amongst these were one third leukaemias. The paper reports first results from a population based case control study which included 466 children with CNS tumours and 2,458 healthy controls. These indicate an increased risk for children with low birth weight and for children whose mothers smoked during pregnancy. Additional data can be found in the Internet (http:¿info.imsd.uni-mainz.de/K_Krebsregister).

Adolescent↗
PubMed2000

Risk of childhood leukemia and parental self-reported occupational exposure to chemicals, dusts, and fumes: results from pooled analyses of German population-based case-control studies.

A recent large-scale United States study reported an association between parental exposure to hydrocarbons at work and the risk of childhood leukemia. Parental occupational exposure to different chemicals and industrial dusts or fumes also was assessed in three German case-control studies that were conducted from 1992-1997. The design and methods of exposure assessment were similar for these studies; therefore, they were pooled for this analysis. In total, these three studies involved 1138 cases of acute lymphocytic leukemia (ALL) and 2962 controls. We found that maternal exposure to paints or lacquers during the preconception period (odds ratio, 1.6; 95% confidence interval, 1.1-2.4) and during the index pregnancy (odds ratio, 2.0; 95% confidence interval, 1.2-3.3) was related to an increased risk of childhood ALL. Whereas our findings for exposure to paints or lacquers confirmed observations from the United States study, we failed to confirm associations between risk of ALL and maternal exposure to solvents and parental exposure to plastic materials. Our studies provide some evidence that parental occupational exposure to certain substances may be associated with cancer risk in offspring; however, more specific studies are needed to identify such substances and the doses that may be hazardous.

Adolescent↗
PubMed1999

Childhood cancer and residential radon exposure - results of a population-based case-control study in Lower Saxony (Germany).

A population-based case-control study on risk factors for childhood malignancies was used to investigate a previously reported association between elevated indoor radon concentrations and childhood cancer, with special regard to leukaemia. The patients were all children suffering from leukaemia and common solid tumours (nephroblastoma, neuroblastoma, rhabdomyosarcoma, central nervous system (CNS) tumours) diagnosed between July 1988 and June 1993 in Lower Saxony (Germany) and aged less than 15 years. Two population-based control groups were matched by age and gender to the leukaemia patients. Long-term (1 year) radon measurements were performed in those homes where the children had been living for at least 1 year, with particular attention being paid to those rooms where they had stayed most of the time. Due to the sequential study design, radon measurements in these rooms could only be done for 36% (82 leukaemias, 82 solid tumours and 209 controls) of the 1038 families initially contacted. Overall mean indoor radon concentrations (27 Bq m(-3)) were low compared with the measured levels in other studies. Using a prespecified cutpoint of 70 Bq m(-3), no association with indoor radon concentrations was seen for the leukaemias (odds ratio (OR): 1.30; 95% confidence interval (95% CI): 0.32-5.33); however, the risk estimates were elevated for the solid tumours (OR: 2.61; 95% CI: 0.96-7.13), mainly based on 6 CNS tumours. We did not find any evidence for an association between indoor radon and childhood leukaemia, which is in line with a recently published American case-control study. There is little support for an association with CNS tumours in the literature.

Adolescent↗
PubMed1999

Association of childhood leukaemia with factors related to the immune system.

The childhood peak of common acute lymphoblastic leukaemia has been proposed as being a rare response to delayed exposure to a common infection. In this context, factors related to the child's immune system are of special interest. Information on such factors was obtained in a recent German case-control study comprising more than 1000 children with acute leukaemia. Neither being the first-born child, nor a short duration of breastfeeding, indicators of a deficit in viral contacts during infancy or the number of infectious diseases, were significant risk factors. We observed a strong association with fewer routine immunizations with a 3.2-fold increase for those children getting less than four immunizations, but this association could partly be explained by reporting bias. While tonsillectomy or appendectomy increased the risk of leukaemia in our studies, a protective effect of allergies could be seen. In summary, we found only weak support for the delayed exposure hypothesis. To some extent this may be due to the chosen surrogate markers which reflect, rather indirectly, immunological isolation in infancy and delayed exposure to common viruses. However, the significant findings for routine immunizations, tonsillectomy and allergies of the child or its parents merit further investigation.

Adolescent↗
PubMed1999

Association of childhood cancer with factors related to pregnancy and birth.

BACKGROUND: It has been hypothesized that risk factors of childhood cancers may already operate during the prenatal and neonatal period. Results of previous epidemiological studies have been inconsistent. METHODS: During 1992-1997 a large case-control study on childhood cancers and a variety of potential risk factors was conducted in Germany. Cases were ascertained by the German Childhood Cancer Registry. Each case was matched to a population-based control of the same age and gender, sampled from the district where the case lived at the date of diagnosis. For the analyses, 2358 cases and 2588 controls were available. RESULTS: Risk of childhood acute leukaemia increased with maternal age < or =20 years at time of delivery (odds ratio [OR] = 1.9, 95% CI: 1.1-3.2), lower (<2500 g: OR = 1.7, 95% CI: 1.1-2.8) and higher birthweight (>4000 g: OR = 1.4, 95% CI: 1.0-1.8, P < 0.05), and hormonal treatment because of infertility (OR = 1.6, 95% CI: 1.0-2.5, P < 0.05). No associations were seen for parental smoking habits, maternal alcohol consumption during pregnancy and fetal losses. Parity was associated only with subgroups of acute leukaemias. Regarding non-Hodgkin's lymphoma we observed an elevated OR for lower birthweight and heavy maternal smoking during pregnancy (>20 cigarettes/day) and a decreased OR for children with one or two siblings. Only a few significant findings were seen for the different groups of solid tumours. CONCLUSIONS: Overall, only weak associations were identified and the evaluated risk factors operating during the neonatal and prenatal period account at most for only a small proportion of childhood cancers.

Adolescent↗
PubMed1999

Associations between childhood cancer and ionizing radiation: results of a population-based case-control study in Germany.

In order to investigate the associations between sources of exposure to ionizing radiation and childhood cancer in Germany, a matched case-control study including children under the age of 15 years was conducted. Cases were identified from the German Childhood Cancer Registry; controls came from population registration offices. Exposure was assessed via questionnaires and parental interviews. The study comprises 1184 leukemia cases, 234 non-Hodgkin's lymphomas, 940 solid tumors, and 2588 controls. Preconception parental occupational exposures were positively but not statistically significantly related to all of the cancer types in the study. Maternal occupational exposure during pregnancy was a risk factor for childhood lymphomas [odds ratio (OR) = 3.87, 95% confidence interval (CI): 1.54-9.75] but not for leukemia or solid tumors. ORs for parental occupational exposures were noticeably more pronounced in leukemia cases who were diagnosed in their first 18 months of life. A preconception paternal occupation in the nuclear industry under dosimetric surveillance yielded an OR of 1.80 (95% CI: 0.71-4.58). However, radiation doses of these fathers were often unknown or below the level of detection, and no dose exceeded 30 mSv. Prenatal X-ray examinations of the father (but not of the mother) were significantly related to childhood leukemia (OR = 1.33; 95% CI: 1.10-1.61). No effects were observed for postnatal X-ray examinations of the child. The results suggest that, in Germany at present, exposures to ionizing radiation do not play a noticeable role in the development of childhood cancers. The major strengths of the study are its size and the population basis. The validity of the data from parental questionnaires and the possibility of residual confounding by socioeconomic factors are potential drawbacks.

Adolescent↗
PubMed1998

Trends in infant leukaemia in West Germany in relation to in utero exposure due to Chernobyl accident.

A temporary increase in the incidence of infant leukaemia in Greece was reported by Petridou et al., which was attributed to in utero exposure to ionising radiation resulting from the Chernobyl accident. We performed a similar analysis based on the data of the German Childhood Cancer Registry in order to check whether the observation could be confirmed by means of independent data. Applying the same definitions as Petridou et al., we also observed an increased incidence of infant leukaemia in a cohort of children born after the Chernobyl accident. More detailed analyses, regarding areas with different contamination levels and dose rate gradients over time after the accident, showed, however, no clear trend with regard to exposure. It would therefore appear less likely that the observed effect was caused by exposure to ionising radiation due to the Chernobyl accident.

Child, Preschool↗
PubMed1998

An extended study on childhood malignancies in the vicinity of German nuclear power plants.

OBJECTIVES: The study was performed to validate exploratory results obtained in a former study on the incidence rates of childhood malignancies in the vicinity of German nuclear power plants and to evaluate the confirmatory results of this previous study. METHODS: Incidence rates near German nuclear installations were compared to rates in control regions based on the German Childhood Cancer Registry. RESULTS: No exploratory result could be reproduced. This is also true for children with acute leukemia younger than 5 years who were living within a 5 km radius of an installation: an observed relative risk (RR) of 1.39 was not significantly increased (95 percent confidence interval CI: 0.69-2.57). Former confirmatory results could be confirmed again. A pooled analysis of both studies based on 2390 cases resulted in RR of 0.99 for all malignancies (CI: 0.91-1.07) and of 1.00 for acute leukemias (CI: 0.87-1.16) (children younger than 15 years of age living within a 15 km radius). CONCLUSIONS: Results did not show significantly increased incidence rates for any subgroup with previously significant exploratory results. Therefore, it appears to be most likely that the previous results were just due to chance. Evaluating the previously confirmatory results with the combined data from the two study periods reassures that incidence rates are not increased in children younger than 15 years who are living within a 15 km radius, either for all malignancies or for acute leukemias. We conclude that at present, in Germany no further investigations of this kind are necessary.

Adolescent↗
PubMed1998

Combined risk estimates for two German population-based case-control studies on residential magnetic fields and childhood acute leukemia.

From 1992 to 1996, we obtained electromagnetic field measurements in two population-based case-control studies on childhood leukemia in the northwestern part of Germany and in Berlin. Exposure assessment comprised residential 24-hour measurements and short-term measurements. We obtained 24-hour measurements for a total of 176 cases and 414 controls. We compared subjects exposed to median 24-hour measurements of 0.2 microT or more with those exposed to lower amounts. Multivariate regression analysis revealed an odds ratio of 2.3 (95% confidence interval = 0.8-6.7).

Acute Disease↗
PubMed1997

Childhood leukemia and electromagnetic fields: results of a population-based case-control study in Germany.

The investigation of an association between increased exposure to residential extremely-low frequency electromagnetic fields (ELF-EMF) and childhood leukemia was part of a population-based case-control study carried out between 1992 and 1995 in the northwestern part of Germany. A total of 129 children with leukemia and 328 controls participated in the EMF-study. Exposure assessment comprised measurements of the magnetic field over 24 hours in the child's bedroom at the residence where the child had been living for the longest period before the date of diagnosis, and spot measurements at all residences where the child had been living for more than one year. The median of the 24h-measurement in the child's bedroom was regarded as the most valid exposure variable. For children exposed to more than 0.2 microT, an elevated but not significant odds ratio (OR) was observed (OR = 3.2, 95 percent confidence interval = 0.7-14.9). These figures are based on only four leukemia cases and three controls since only 1.5 percent of the study population was classified as highly exposed. Exploratory analyses revealed ORs that were not statistically significantly increased for other characteristics of the magnetic field at varying cut-points. The results are comparable with those from other studies. Although not statistically significant, they may indicate a positive association between EMF and childhood leukemia.

Adolescent↗
PubMed1996

Vitamin K and childhood cancer: a population based case-control study in Lower Saxony, Germany.

OBJECTIVE: To confirm or refute a possible association of parenteral vitamin K prophylaxis and childhood cancer. DESIGN: Population based case-control study. Comparison of vitamin K exposure in children with leukaemia or other common tumours with two control groups. SETTING: State of Lower Saxony (north western part of Germany); case recruitment from the German childhood cancer registry. SUBJECTS: 272 children with leukaemia, nephroblastoma, neuroblastoma, rhabdomyosarcoma, and tumours of the central nervous system diagnosed between 1 July 1988 and 30 June 1993; children were aged between 30 days and 15 years at diagnosis. 334 population based controls without diagnoses of cancer matched to the leukaemia cases for age and sex. MAIN EXPOSURE MEASURES: Parenteral vitamin K prophylaxis (intramuscular and subcutaneous) versus oral and no vitamin K prophylaxis. RESULTS: An association between parenteral vitamin K exposure and childhood cancer (leukaemias and other tumours combined) could not be confirmed (odds ratio 1.04, 95% confidence interval 0.74 to 1.48). For leukaemias the observed odds ratio was only 0.98 (0.64 to 1.50) (comparison of leukaemia cases with local controls 1.24 (0.68 to 2.25); state controls 0.82 (0.50 to 1.36)). These odds ratios remained almost unchanged when several potential confounders were considered in the logistic regression model. CONCLUSIONS: This population based study adds substantial evidence that there is no association between parenteral vitamin K and childhood cancer.

Adolescent↗
PubMed1996

Childhood leukaemia and exposure to pesticides: results of a case-control study in northern Germany.

The association between childhood leukaemia and exposure to pesticides was examined in a population-based case-control study conducted in Lower Saxony, Northern Germany. Between July 1988 and June 1992, 219 newly diagnosed cases were identified, of whom 173 participated in the study. Two sex- and age-matched control groups were recruited: local controls from the same communities as the newly diagnosed cases of leukaemia and state controls from other randomly selected communities in Lower Saxony. An additional study group consisted of 175 cases of solid tumours. When the leukaemia cases were compared with the local controls, positive associations with parental occupational exposure, particularly agriculture-related exposure, were observed, which were statistically non-significant. A significant association was found for pesticide use in gardens (odds ratio = 2.52, 95% confidence interval: 1.0-6.1). No positive associations were seen when the leukaemia cases were compared to the state controls, but this finding could be explained by a higher proportion of state controls living in rural areas. In communities with a significantly elevated standardised incidence ratio of childhood leukaemia over the last decade (1984-1993), the prevalence of pesticide use in the garden was 21%, compared with the 10% in other communities. None of the examined risk factors were more common among cases of solid tumours. Our findings add some evidence to the hypothesis that pesticides are a risk factor for childhood leukaemia, and there are good reasons to consider abundant pesticide use in rural areas as a possible cause for clustering of childhood leukaemia.

Adolescent↗
PubMedDate not supplied

German case control study on childhood leukaemia--basic considerations, methodology and summary of the results.

In order to explore potential risk factors of childhood leukaemia, a case control study was performed including all incident cases from 1992 to 1994. The study was based on the German Childhood Cancer Registry. It was restricted to cases from West Germany and extended retrospectively until 1980 for children who were living in regions covered by a previous incidence study on nuclear installations (21). The study was conducted in close correspondence with a preceding case control study in Lower Saxony (13). Results of this study and of others published in the literature were used to define explicit hypotheses for the present study. This paper presents the methodology of the study and gives an overview of some basic results. More detailed analyses of the investigated potential risk factors will be published elsewhere. The study comprised a total of 2358 cases (leukaemias, lymphomas, selected tumours) and 2588 controls. Response rates were 81% for cases and 67% for controls. For leukaemias, the main results regarding maternal factors, pregnancy, birth, immune system, ionising radiation, parental occupation and environmental factors were as follows: Positive associations were observed between childhood leukaemias and young maternal age at birth, high birth weight, tonsillectomy and use of pesticides. Some results suggest a protective effect for allergies and vaccinations. A negative association was observed with maternal smoking and childhood leukaemia. No associations were found with frequency of stillbirths, maternal alcohol consumption, parental exposure to benzene and use of wood preservatives. X-ray examinations in early childhood and parental radiation exposure did not show any consistent associations with leukaemia. Potential risk factors were not reported more frequently by cases and controls living in 114 communities with increased incidence rates. The strength of our study lies in the large number of participating families and in the population-based approach.

Adolescent↗