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Biomedical subjects

K H Jöckel

Publications and source records attributed to K H Jöckel.

At least 19 recordsLinked to original sources
PubMed2006

Methacholine challenge tests: sample sizes required in crossover trials.

OBJECTIVE: Methacholine challenge testing is common for assessing the pharmacodynamic properties of anti-asthma drugs. In order to design studies and to interpret published studies, sample size calculations are essential. Unfortunately, wrong sample sizes were previously reported in the literature. We present correct sample sizes required for the comparison of two treatments based on methacholine challenge testing in a crossover study. METHODS AND RESULTS: Formulas for sample size calculations and the resulting number of subjects required for a specified power are presented for studies designed to show a difference as well as for equivalence and non-inferiority studies. CONCLUSIONS: A much larger sample size is required for methacholine challenge testing than previously reported.

Algorithms↗
PubMed2005

Incidence of skin lymphoma in Germany.

PURPOSE: Population-based analyses of the incidence of skin lymphoma in Europe are very sparse. We analyzed German population-based incidence data on skin lymphoma to study the descriptive epidemiology of these tumors. METHODS: We extracted skin lymphoma cases from the registry files of the East German National Cancer Registry (1976-1989) and registries of three new federal states (1998-2002) (Sachsen, Brandenburg, Mecklenburg-Vorpommern), the Cancer Registry Schleswig-Holstein, Lübeck (1998-2002), and the Epidemiological Cancer Registry Münster (1998-2002). We calculated age-standardized incidence rates (world standard population) and compared these figures with international data. RESULTS: From 1976 through 1989, 619 cases of skin lymphoma were registered in the former German Democratic Republic. During this period, the incidence among men increased from 2.0 to 2.5 per million and decreased among women from 1.5 to 0.8 per million. Current age-standardized incidence rates of skin lymphoma (1998-2002) varied by sex and registry and were about 3.2-6.0 per million among men and 1.6-2.6 per million among women. CONCLUSIONS: The current incidence rates among the registries of Germany are fairly similar but are considerably lower than incidence rates from the United States and Israel. Several methodological issues hamper the analysis of population-based incidence data of skin lymphoma.

Adult↗
PubMed2005

Baseline recruitment and analyses of nonresponse of the Heinz Nixdorf Recall Study: identifiability of phone numbers as the major determinant of response.

The Heinz Nixdorf Recall Study is an ongoing population-based prospective cardiovascular cohort study of the Ruhr area in Germany. This paper focuses on the recruitment strategy and its response results including a comparison of participants of the baseline examination with nonparticipants. Random samples of the general population were drawn from residents' registration offices including men and women aged 45-74 years. We used a multimode contact approach including an invitational letter, a maximum of two reminder letters and phone calls for the recruitment of study subjects. Nonparticipants were asked to fill in a short questionnaire. We calculated proportions of response, contact, cooperation and recruitment efficacy to characterize the participation. Overall, 4487 eligible subjects participated in our study. Although the elderly (65-75 years) had the highest contact proportion, the cooperation proportion was the lowest among both men and women. The recruitment efficacy proportion was highest among subjects aged 55-64 years. The identifiability of the phone number of study subjects was an important determinant of response. The recruitment efficacy proportion among subjects without an identified phone number was 11.4% as compared to 65.3% among subjects with an identified phone number. The majority of subjects agreed to participate after one invitational letter only (52.6%). A second reminding letter contributed only very few participants to the study. Nonparticipants were more often current smokers than participants and less often belonged to the highest social class. Living in a regular relationship with a partner was more often reported among participants than nonparticipants.

Age Factors↗
PubMed2005

Population-based incidence rates of malignant melanoma of the vulva in Germany.

OBJECTIVES: Only few population-based incidence analyses of vulvar melanoma including the United States and Sweden are currently available. We studied the incidence of vulvar melanoma in a large population-based cancer registry of East Germany and compared our findings with the United States and Sweden. METHODS: We extracted vulvar melanoma registered between 1976 and 1989 in the former National Cancer Registry of the German Democratic Republic (GDR) and of three new East German cancer registries of the federal states of Sachsen, Brandenburg, and Mecklenburg-Vorpommern of the period 1998 to 2002. We calculated age-specific and age-standardized incidence rates using the World Standard Population. RESULTS: One hundred two cases (1976-1989, former GDR) and twenty-five cases of vulvar melanoma (1998-2002, three new federal states) were registered. The age-standardized incidence rate (World Standard Population) remained constant over the period from 1976 to 1989 and ranged between 0.26 and 0.52 cases per million. From 1998 to 2002, the incidence rate was 0.48 per million. The ratio of registered vulvar melanoma to skin melanoma was 1:71, and the ratio of vaginal melanoma to skin melanoma was 1:314. Age at diagnosis during the period 1976 to 1989 was lower among women with vulvar melanoma (median age 70 years) compared to women with vulvar tumors other than melanoma (median age 73 years). CONCLUSIONS: The risk of vulvar melanoma was considerably lower in East Germany than in the United States and Sweden. Due to the rarity of vulvar melanoma, population-based cancer registries are hampered to study this tumor in detail.

Age Factors↗
PubMed2004

[Health-related control belief and quality of life in chronically ill patients after a behavioral intervention in an integrative medicine clinic--an observational study].

BACKGROUND: In 1999 the Clinic for Internal Medicine and Integrative Medicine was founded in Essen as a regular part of the German inpatient health care system. Integrative medicine (standard internal medicine, evidence-based complementary and alternative medicine combined with intensified lifestyle modification) aims to help patients with chronic illness to cope with their condition more effectively and to achieve a health-promoting lifestyle. Techniques include cognitive restructuring, the elicitation of the relaxation response, and lifestyle education. The goal is to increase health-related quality of life (QoL) as well as control beliefs and to reduce morbidity in later life. AIM: To demonstrate changes in quality of life, lifestyle, and control beliefs after a two-week hospital stay. METHODS: Uncontrolled prospective observational study with 557 consecutive hospital patients. Outcome parameters were quality of life (SF36), control beliefs (GKU), and daily health-related behavior (nutrition, physical activity, relaxation) on admission, at discharge, as well as 3 and 6 months after discharge. RESULTS: Weekly physical activity increases by 29%, consumption of not recommendable foods decreases by 18%. The majority of patients (57%) engage in relaxation exercises 6 months after discharge (on admission 23%). The physical sum scale (SF36) increases from 33.9 (95% KI 32.5-35.3) on admission to 37.3 (35.8-38.9) 6 months after discharge, the mental sum scale from 41.2 (39.5-42.9) to 45.1 (43.5-46.7). The ratio internal/external control belief rises from 1.17 (95% KI 1.11-1.24) to 1.32 (1.24-1.40). Pretherapeutic ratio internal/external control belief and its increase are associated with rises in QoL. CONCLUSIONS: After integrative medicine treatment a lasting increase in QoL and lifestyle changes can be achieved. Reinforcement of internal control beliefs and own competence is possible and enhances outcomes in chronically ill patients.

Behavior Therapy↗
PubMed2001

A scheme for a dose-escalation study when the event is lagged.

Classical designs for clinical phase I trials assume that information about a dose-limiting event (DLE) is available for all the included patients, or advise not to treat new patients until the information is present. If a DLE occurs after a lag, however, information at the current time might not be sufficient to make clear-cut decisions according to these designs. In particular, if new patients are available, it is not clear whether to include them in the trial. We suggest a rule that decides on the accrual of each individual eligible patient. Simulation studies are presented that indicate an advantage over the standard 'three-at-once' design in the length of the study.

Boron Neutron Capture Therapy↗
PubMed2001

Lung cancer and cigarette smoking in Europe: an update of risk estimates and an assessment of inter-country heterogeneity.

Ten case-control studies have been carried out in 6 European countries to investigate the major risk factors for lung cancer. Carcinogenic effect from cigarette smoke was the most relevant interest in our study, which has included 7,609 cases of lung cancer and 10,431 controls, mainly population based. The results indicate elevated odds ratios (ORs; 23.9 among men and 8.7 among women) with attributable risks exceeding 90% for men and close to 60% for women. A large, and statistically significant, variability of the results across countries was detected after adjusting for the most common confounding variables, and after controlling, at least in part, for the instability of the ORs due to the small number of non-smokers in some of the study subsets. This pattern of lung cancer risk associated with cigarettes smoke, across different European regions, reflects inherent characteristics of the studies as well as differences in smoking habits, particularly calendar periods of starting, and it is likely to have been influenced by effect modifiers like indoor radon exposure, occupation, air pollution and dietary habits.

Aged↗
PubMed2001

Asbestos and man-made vitreous fibers as risk factors for diffuse malignant mesothelioma: results from a German hospital-based case-control study.

BACKGROUND: This study examines the role of occupational factors in the development of diffuse malignant mesothelioma with special emphasis on the dose-response relationship for asbestos and on the exposure to man-made vitreous fibers (MMVFs). METHODS: One hundred and twenty-five male cases, diagnosed by a panel of pathologists, were personally interviewed concerning their occupational and smoking history. The same number of population controls (matched for sex, age and region of residence) underwent similar interviews by trained interviewers. Odds ratios (OR) were calculated for an expert-based exposure index using conditional logistic regression. RESULTS: Exposure to asbestos shows the expected sharp gradient with an OR of about 45 for a cumulative exposure > 1.5 fiber years (arithmetic mean 16 fiber years). A significant OR was calculated even for the lowest exposure category "> 0 - < or = 0.15 fiber years". Although the mean cumulative exposure to MMVF is roughly 10% of the exposure to asbestos, an increased OR is observed in an ever/never evaluation. This observation is heavily hampered by methodical problems. A corresponding case-control study was performed using a lung tissue fiber analysis in addition to interviews. Both interviews and the lung tissue analysis yielded similar OR levels between the reference and the maximum exposure intervals. CONCLUSIONS: Despite a possible influence as a result of selection and information bias, our results confirm the previously reported observation of a distinct dose-response relationship even at levels of cumulative exposure below 1 fiber year. Moreover, the study confirms that asbestos is a relevant confounder for MMVF. A causal relationship between exposure to MMVF and mesothelioma could neither be detected nor excluded, as in other studies.

Aged↗
PubMed2001

The contribution of cigarette smoking to bladder cancer in women (pooled European data).

BACKGROUND: Using a combined analysis of 11 case-control studies from Europe, we have investigated the relationship between cigarette smoking and bladder cancer in women. METHODS: Available smoking information on 685 female bladder cancer cases and 2416 female controls included duration of smoking habit, number of cigarettes smoked per day, and time since cessation of smoking habit for ex-smokers. RESULTS: There was an increasing risk of bladder cancer with increasing duration of smoking, ranging from approximately a two-fold increased risk for a duration of less than 10 years (odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.1-3.1) to over a four-fold increased risk for a duration of greater than 40 years (OR = 4.1, 95% CI 3.0-5.5). A dose-response relationship was observed between number of cigarettes smoked per day and bladder cancer up to a threshold limit of 15-20 cigarettes per day, OR = 3.8 (95% CI 2.7-5.4), after which no increased risk was observed. An immediate decrease in risk of bladder cancer was observed for those who gave up smoking. This decrease was over 30% in the immediate 1-4 years after cessation, OR = 0.68 (95% CI 0.38-1.2). However, even after 25 years the decrease in risk did not reach the level of the never-smokers, OR = 0.27 (95% CI 0.21-0.35). CONCLUSION: The proportion of bladder cancer cases among women attributable to ever smoking was 0.30, (0.25-0.35) and to current smoking was 0.18 (0.14-0.22). These attributable proportions are less than those observed among men, although they are likely to increase in the future as the smoking-related disease epidemic among women matures.

Adult↗
PubMed2001

Undescended testis and the risk of testicular cancer: importance of source and classification of exposure information.

BACKGROUND: The strength of the association between undescended testis and testicular cancer varies considerably across studies. Here we report the effect of various classifications of self-reported history of undescended testis and different data sources on the estimates of the risk of testicular cancer from a case-control study. METHODS: We performed a population-based case-control study including 269 testicular cancer cases and 797 controls matched on age and region. Medical history was assessed by interviews (index persons) and mailed questionnaires (mothers). We used conditional logistic regression to calculate odds ratios (OR) and kappa coefficients to assess agreement between different sources of information. RESULTS: Odds ratios for testicular cancer ranged between 2.4 and 5.4 based on the sons' self-reports and between 1.1 and 1.9 based on the mothers' reports. The agreement between the sons and mothers on undescended, gliding or retractile testis was fair (kappa 0.53) and was good when these conditions were treated by surgery (kappa 0.89). The rating of a history of undescended testis by two urologists was fair (kappa 0.54). CONCLUSIONS: The questionnaire design, the classifications of undescended testis and data sources have an important impact on the OR for the association of undescended testis and testicular cancer. These factors may partially explain the heterogeneity of the OR for this association in case-control studies relying on self-reports.

Adolescent↗
PubMed2001

The possible role of radiofrequency radiation in the development of uveal melanoma.

There are few epidemiologic studies dealing with electromagnetic radiation and uveal melanoma. The majority of these studies are exploratory and are based on job and industry titles only. We conducted a hospital-based and population-based case-control study of uveal melanoma and occupational exposures to different sources of electromagnetic radiation, including radiofrequency radiation. We then pooled these results. We interviewed a total of 118 female and male cases with uveal melanoma and 475 controls matching on sex, age, and study regions. Exposure to radiofrequency-transmitting devices was rated as (a) no radiofrequency radiation exposure, (b) possible exposure to mobile phones, or (c) probable/certain exposure to mobile phones. Exposures were rated independently by two of the authors who did not know case or control status. We used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). We found an elevated risk for exposure to radiofrequency-transmitting devices (exposure to radio sets, OR = 3.0, 95% CI = 1.4-6.3; probable/certain exposure to mobile phones, OR = 4.2, 95% CI = 1.2-14.5). Other sources of electromagnetic radiation such as high-voltage lines, electrical machines, complex electrical environments, visual display terminals, or radar units were not associated with uveal melanoma. This is the first study describing an association between radiofrequency radiation exposure and uveal melanoma. Several methodologic limitations prevent our results from providing clear evidence on the hypothesized association.

Adolescent↗
PubMed2001

Skin melanoma in Saarland: incidence, survival and mortality 1970-1996.

Over the past few decades, the incidence of cutaneous malignant melanoma has been rising in both sexes in almost all developed countries, notably those with fair-skinned populations. Detailed population-based time trend analyses of skin melanoma incidence and survival in Germany accounting for stage have not been published until now. We analysed skin melanoma data from the population-based Saarland Cancer Registry in Germany from 1970 to 1996. Incidence rates were age-standardized. We estimated 5-year disease-specific survival rates and evaluated the effects of sex, age, calendar period and staging on the prognosis in Cox's proportional hazards models. From 1970-1972 to 1994-1996, melanoma incidence increased 170% from 2.4 to 6.5 per 100 000 person-years among men and 150% from 2.4 to 6.0 per 100 000 person-years among women. Mortality rates peaked in 1988-1990. After 1988-1990, mortality rates declined among women and remained roughly constant among men. The increase in the incidence of localized melanoma and T1-T2 melanoma respectively is driving the overall incidence trend. The improvement of survival over time is most likely due to earlier detection of skin melanoma. In the 1990s, about 30% of all newly diagnosed skin melanoma had stage T3 or T4, implying that further improvement in survival by earlier detection is feasible.

Adult↗
PubMed2001

Biomonitoring on carcinogenic metals and oxidative DNA damage in a cross-sectional study.

Oxidative DNA damage is mediated by reactive oxygen species and is supposed to play an important role in various diseases including cancer. The endogenous amount of reactive oxygen species may be enhanced by the exposure to genotoxic metals. A cross-sectional study was conducted from 1993 to 1994 in an urban population in Germany to investigate the association between metal exposure and oxidative DNA damage. The cross-sectional sample of 824 participants was recruited from the registry of residents in Bremen, comprising about two-third males and one-third females with an average age of 61.1 years. A standardized questionnaire was used to obtain the occupational and smoking history. The incorporated dose of exposure to metals was assessed by biological monitoring. Chromium, cadmium, and nickel were measured in 593 urine samples. Lead was determined in blood samples of 227 participants. As a biomarker for oxidative DNA damage, 7,8-dihydro-8-oxoguanine has been analyzed in lymphocytes of 201 participants. Oxidative lesions were identified by single strand breaks induced by the bacterial formamidopyrimidine-DNA glycosylase (Fpg) in combination with the alkaline unwinding approach. The concentrations of metals indicate a low body load (median values: 1.0 microg nickel/l urine, 0.4 microg cadmium/l urine, and 46 microg lead/l blood; 83% of chromium measures were below the technical detection limit of 0.3 microg/l). The median level of Fpg-sensitive DNA lesions was 0.23 lesions/10(6) bp. A positive association between nickel and the rate of oxidative DNA lesions (Fpg-sensitive sites) was observed (odds ratio, 2.15; tertiles 1 versus 3, P < 0.05), which provides further evidence for the genotoxic effect of nickel in the general population.

Adult↗
PubMed2000

[Risk factors and surgery rates in gallstones. Results of a population-based study].

STUDY OBJECTIVE: The prevalence of gallstone disease, time trends in the frequency of cholecystectomies and risk factors for the occurrence of cholelithiasis were examined in a cross-sectional population study. METHODS: The survey was based on a random sample from the populations of 4 regions in Germany, stratified by region, age and sex. Information on the frequency of gallstone disease and on potential risk factors were collected by standardized interviews. For the statistical analysis, multiple logistic regression was used. RESULTS: Overall, 1,085 persons were interviewed. The age-standardized prevalence of known gallstones was 4.2% for men and 14.5% for women. The frequency of cholecystectomy almost tripled in women from 1985 to 1994 as compared to 1975 to 1984 despite a decreasing trend in gallstone diagnoses in the same time period. No such trend was apparent in men. In men, age, body weight, changes in body weight, diabetes and use of corticosteroids were identified as risk factors for gallstone disease. In women, gallstone disease was also associated with body weight, changes in body weight and age, and, in addition, the number of births. An inverse association with gallstone disease was found for use of oral contraceptives and level of education in women.

Adolescent↗
PubMed2000

Lung cancer and cigarette smoking in women: a multicenter case-control study in Europe.

The association between cigarette smoking and lung cancer risk in women was investigated within the framework of a case-control study in 9 centres from 6 European countries. Cases were 1,556 women up to 75 years of age with histologically confirmed primary lung cancer; 2, 450 controls with age distribution similar to cases were selected. The predominant cell type was adenocarcinoma (33.5%), with similar proportions for squamous-cell type (26.4%) and small-cell carcinoma (22.3%). Overall, smoking cigarettes at any time was associated with a 5-fold increase in lung cancer risk (odds ratio 5.21, 95% confidence interval 4.49-6.04); corresponding figures for current smoking habits were 8.94, 7.54-10.6. The association showed a dose-response relationship with duration of the habit and daily and cumulative lifetime smoking. A significant excess risk of 70% was associated with every 10 pack-years smoked. After 10 years of smoking cessation, the relative risk decreased to 20% compared to current smokers. The following characteristics were associated with a higher relative risk: inhalation of smoke, smoking non-filter cigarettes, smoking dark-type cigarettes and starting at young age. The association was observed for all major histological types, being the strongest for small-cell type carcinoma, followed by squamous-cell type and the lowest for adenocarcinoma. The proportion of lung-cancer cases in the population attributable to cigarette smoking ranged from 14% to 85%. We concluded that women share most features of the association between cigarette smoking and lung cancer observed in men.

Adult↗
PubMed2000

Aggregation of lung cancer in families: results from a population-based case-control study in Germany.

The authors investigated familial aggregation of lung cancer by means of a population-based case-control study, conducted in Germany between 1988 and 1993. They compared lung cancer prevalence in first degree relatives of 945 patients and 983 controls, accounting for various potential risk factors using logistic regression and generalized estimating equations. Some 83% of the study participants were male, and about 14% were below age 51 (young age group). Overall, lung cancer in parents or siblings was associated with a 1.67-fold (95% confidence interval (CI): 1.11, 2.52) increase in lung cancer risk. For the young participants, this risk was 4.75 (95% CI: 1.20, 18.77). Having multiple affected relatives (two or more) was related to a threefold risk elevation (odds ratio (OR) = 2.99, 95% CI: 0.32, 27.55). Paternal (OR = 1.64, 95% CI: 0.91, 2.96) but not maternal (OR = 0.91, 95% CI: 0.32, 2.61) lung cancer was associated with an increased risk of the disease. Lung cancer risk from smoking was particularly pronounced in the parents of cases (OR = 12.20, 95% CI: 3.34, 44.62 vs. OR = 7.93, 95% CI: 2.43, 25.91 in parents of controls). No risk elevation was detected for other smoking-related and other cancers in general. Results confirm previous findings and support the etiologic role of a genetic predisposition to lung cancer.

Adult↗
PubMed2000

Cigarette smoking and bladder cancer in men: a pooled analysis of 11 case-control studies.

The primary risk factor for bladder cancer is cigarette smoking. Using a combined analysis of 11 case-control studies, we have accurately measured the relationship between cigarette smoking and bladder cancer in men. Available smoking information on 2,600 male bladder cancer cases and 5,524 male controls included duration of smoking habit, number of cigarettes smoked per day and time since cessation of smoking habit for ex-smokers. There was a linear increasing risk of bladder cancer with increasing duration of smoking, ranging from an odds ratio (OR) of 1.96 after 20 years of smoking (95% confidence interval [CI] 1.48-2.61) to 5.57 after 60 years (CI 4.18-7.44). A dose relationship was observed between number of cigarettes smoked per day and bladder cancer up to a threshold limit of 15-20 cigarettes per day, OR = 4.50 (CI 3.81-5. 33), after which no increased risk was observed. An immediate decrease in risk of bladder cancer was observed for those who gave up smoking. This decrease was over 30% after 1-4 years, OR = 0.65 (0. 53-0.79), and was over 60% after 25 years of cessation, OR = 0.37 (0. 30-0.45). However, even after 25 years, the decrease in risk did not reach the level of the never-smokers, OR = 0.20. (0.17-0.24). The proportion of bladder cancer cases attributable to ever-smoking was 0.66 (0.61-0.70) for all men and 0.73 (0.66-0.79) for men younger than 60. These estimates are higher than previously calculated.

Adult↗