Hajo Zeeb

Mortality from cancer and other causes among male airline cockpit crew in Europe

Airline pilots and flight engineers are exposed to ionizing radiation of cosmic origin and other occupational and life‐style factors that may influence their health status and mortality. In a cohort study in 9 European countries we studied the mortality of this occupational group. Cockpit crew cohorts were identified and followed‐up in Denmark, Finland, Germany, Great Britain, Greece, Iceland, Italy, Norway and Sweden, including a total of 28,000 persons. Observed and expected deaths for the period 1960–97 were compared based on national mortality rates. The influence of period and duration of employment was analyzed in stratified and Poisson regression analyses. The study comprised 547,564 person‐years at risk, and 2,244 deaths were recorded in male cockpit crew (standardized mortality ratio [SMR] = 0.64, 95% confidence interval [CI] = 0.61–0.67). Overall cancer mortality was decreased (SMR = 0.68; 95% CI = 0.63–0.74). We found an increased mortality from malignant melanoma (SMR = 1.78, 95% CI = 1.15–2.67) and a reduced mortality from lung cancer (SMR = 0.53, 95% CI = 0.44–0.62). No consistent association between employment period or duration and cancer mortality was observed. A low cardiovascular mortality and an increased mortality caused by aviation accidents were noted. Our study shows that cockpit crew have a low overall mortality. The results are consistent with previous reports of an increased risk of malignant melanoma in airline pilots. Occupational risk factors apart from aircraft accidents seem to be of limited influence with regard to the mortality of cockpit crew in Europe.

Decreasing sperm quality: a global problem?

BackgroundCarlsen and coworkers (1992) reviewed 61 heterogeneous observational studies on semen quality published between 1938 and 1990. This review indicates that mean sperm density decreased significantly between 1940 and 1990. An extended meta-analysis with 101 studies confirmed a decline in sperm density for the period from 1934 to 1996 (2000). The key message of the meta-analyses is that sperm counts have decreased globally by about 50% over the past decades. This assessment has been questioned.DiscussionA major methodological problem of the meta-analysis is the use of data collected in different countries, at different times, on different populations and with different methods of semen analysis. Furthermore, the results of studies concerning semen analysis are frequently biased e.g. by selection criteria of volunteers. In most studies on human semen characteristics the populations under study are insufficiently defined and the study participants are not a representative population sample. The incidence of testicular cancer has increased in Caucasian men worldwide. The investigation of common risk factors for male reproductive disorders requires well designed epidemiological studies and the collection of individual data.SummaryFormer meta-analyses of sperm count data show a global downward trend. This conclusion should be interpreted with caution. The included studies are of great heterogeneity due to geographical and/or ethnical variation, different study designs and different methodological standards. Population-based prospective studies are needed to investigate secular trends in male reproductive disorders.

How useful is a name-based algorithm in health research among Turkish migrants in Germany?

Migrants often face particular social, economic and health disadvantages relative to the population of the host country. In order to adapt health services to the needs of migrants, health researchers need to identify differences in risk factor and disease profiles, as well as inequalities concerning treatment and prevention. Registries of health‐related events could be employed for these purposes. In Germany, however, routine data bases often hold no, or inaccurate, information on the national origin of the cases registered. We developed an algorithm based on a large data set of Turkish family and first names (n=15u2003000), with religion as additional criterion, to identify cases of Turkish origin in registries in a largely automatic search. We tested the performance of the algorithm in a population registry and in a cancer registry. The algorithm discriminates well against Greek and Arab names, with 1% false positive matches in our study. It achieves a specificity of >u200399.9% in delimiting Turkish from German cases in the cancer registry. The sensitivity can be increased to 85%, provided the small proportion of case records with uncertain origin can be assessed manually. The name algorithm can be useful for registry‐based health research among Turkish migrants in Germany. Possible applications are e.g. in cancer registries to compare survival among German and Turkish cancer patients, or in health insurance registries to compare the relative importance of work‐related degenerative diseases. In specific circumstances, the algorithm may also be useful in aetiological research.

Cohort Mortality Study of German Cockpit Crew, 1960 -1997

Background. Cockpit crew in civil aviation are exposed to several potential health hazards, among them cosmic ionizing radiation. To assess the influence of occupational and other factors on mortality we conducted a cohort study among cockpit crew. Methods. All pilots and other cockpit personnel of two German airlines were traced through registries and other sources for the period 1960–1997. Standardized mortality ratios, with German population rates as the reference, were calculated. We estimated the individual radiation dose based on individual job histories and assessed dose-response trends in stratified and regression analyses. Results. We compiled a cohort of 6061 male cockpit personnel, yielding 105,037 person-years of observation. The maximum estimated individual radiation dose was 80.5 mSv. Among 255 deaths overall (standardized mortality ratio [SMR] = 0.48; 95% confidence interval [CI] = 0.42–0.54) there were 76 cancer deaths (SMR = 0.56; CI = 0.43 – 0.74). Most cancer and cardiovascular SMRs were reduced. A slight increase was seen for brain cancer (SMR = 1.68; CI = 0.66–3.62). Employment duration was associated with the all-cancer mortality in Poisson regression analyses. No other dose-response relation was found. Conclusions. German cockpit crew have a low overall and cancer mortality. The role of occupational causes, and particularly cosmic radiation, appears limited.

Epidemiological studies of cancer in aircrew.

Exposure to cosmic ionising radiation, in addition to other specific occupational risks, is of concern to aircrew members. Epidemiological studies provide an objective way to assess the health of this occupational group. We systematically reviewed the epidemiological literature on health of aircrew members since 1990, focusing on cancer as the endpoint of interest. Sixty-five relevant publications were identified and reviewed. Whereas overall cancer incidence and mortality was generally lower than in the comparison population, consistently elevated risks were reported for breast cancer incidence in female aircrew members and for melanoma in both male and female aircrew members. Brain cancer was increased in some studies among pilots. Occasionally trends of increasing cancer mortality or incidence with increasing estimated radiation dose were reported. Ionising radiation is considered to contribute little if at all to the elevated risks for cancers among aircrew, whereas excess ultraviolet radiation is a probable cause of the increased melanoma risk.

Diesel motor emissions and lung cancer mortality - results of the second follow-up of a cohort study in potash miners.

International health authorities have graded diesel motor emissions (DME) as probably cancerogenic in human beings. There are gaps in epidemiological evidence regarding exact exposure quantification, confounder control and the investigation of highly exposed populations. We investigated the association of DME and lung cancer mortality in a historical cohort study of 5,862 German potash miners who were followed from 1970 to 2001. Cumulative exposure (CE) was measured by representative concentrations of total carbon multiplied with exposure years from the mines medical records. Exposure and smoking behavior were validated by interviews of 3,087 participants. We computed standardized mortality ratios (SMR, external comparison) and performed Cox regression (internal comparison). The relative risk estimates (RR) with 95%‐confidence intervals were adjusted for age and smoking. Vital status and causes of death were confirmed for 98.1% of participants. Sixty‐one lung cancer deaths occurred. SMR‐analysis showed lower than expected lung cancer mortality (healthy‐worker‐effect). Internal comparisons revealed risk elevations from moderate to risk doubling depending on the exposure categories used (dichotomized: up to RR 1.43[0.67–3.03] for a CE of 4.90[mg/m3]*years as compared with less exposure; quintiles: RR 1.13[0.46–2.75], 2.47[1.02–6.02], 1.50[0.56–4.04] and 2.28[0.87–5.97] for a CE up to 2.04, 2.73, 3.90 and >3.90, respectively, as compared with the reference of <1.29[mg/m3]*years). Additional adjustment of length of follow‐up leads to further RR increases and indicates healthy‐worker‐survivor‐phenomena. The analyses of a sub‐cohort (n = 3,335) with particularly accurate exposure measurement revealed a nonsignificant dose‐response‐relationship. Our results support an association of DME and lung cancer mortality.

Paediatric CT scan usage and referrals of children to computed tomography in Germany-a cross-sectional survey of medical practice and awareness of radiation related health risks among physicians

BackgroundComputed tomography (CT) is a major source of ionizing radiation exposure in medical diagnostic. Compared to adults, children are supposed to be more susceptible to health risks related to radiation. The purpose of a cross-sectional survey among office-based physicians in Germany was the assessment of medical practice in paediatric CT referrals and to investigate physicians knowledge of radiation doses and potential health risks of radiation exposure from CT in children.MethodsA standardized questionnaire was distributed to all paediatricians and surgeons in two defined study areas. Furthermore, the study population included a random sample of general practitioners in the two areas. The questionnaire covered the frequency of referrals for paediatric CT examinations, the medical diagnoses leading to paediatric CT referrals, physicians knowledge of radiation doses and potential health risks of radiation exposure from CT in children.ResultsA total of 295 (36.4%) physicians responded. 59% of the doctors had not referred a child to CT in the past year, and approximately 30% referred only 1-5 children annually. The most frequent indications for a CT examination in children were trauma or a suspected cancer. 42% of the referrals were related to minor diagnoses or unspecific symptoms. The participants underestimated the radiation exposure due to CT and they overestimated the radiation exposure due to conventional X-ray examinations.ConclusionsIn Germany, the frequency of referrals of children to computed tomography is moderate. The knowledge on the risks from radiation exposure among office-based physicians in our sample varied, but there was a tendency to underestimate potential CT risks. Advanced radiological training might lead to considerable amendments in terms of knowledge and practice of CT referral.

Suicide mortality among Turks in Germany

ZusammenfassungHintergrundDie Suizidsterblichkeit liegt weltweit unter Männern meist höher als unter Frauen. In sozial benachteiligten Gruppen kann sich das Verhältnis umkehren. Wir untersuchten, ob dies bei in Deutschland lebenden Türkinnen und Türken der Fall ist.Material und MethodenWir berechneten alters- und geschlechtsspezifische Suizidraten für in (West-)Deutschland lebende türkische Staatsbürger (1.186 Suizide) und für Deutsche unter 65xa0Jahren anhand einer Sonderauswertung der Todesursachenstatistik 1980–1997.ErgebnisseDie altersadjustierten Suizidraten lagen bei Türken niedriger als bei Deutschen (relatives Risiko 0,3). Bei türkischen Mädchen und jungen Frauen unter 18xa0Jahren betrug das relative Risiko jedoch 1,8 (95% KI: 1,4–2,3) gegenüber gleichaltrigen Deutschen. Das Verhältnis der Suizidraten von Männern gegenüber Frauen beträgt in dieser Altersgruppe bei Deutschen 3,2, bei Türken 0,6.DiskussionIn Deutschland lebende Türken haben insgesamt eine niedrigere Suizidsterblichkeit als Deutsche. Mögliche Erklärungen sind eine ausgeprägte soziale Kohärenz und religiöse Verbote. Die hohe Suizidrate unter jungen Türkinnen könnte auf sozial oder kulturell bedingte Konfliktsituationen hinweisen.SummaryBackgroundSuicide mortality is usually higher among men than among women. In socially disadvantaged groups, this relationship can be reversed. We investigated whether this is the case among Turkish migrants in Germany.Material and methodsWe calculated age- and sex-specific suicide rates for Turkish nationals residing in (West) Germany (1186 suicides) and for Germans aged below 65xa0years based on death registration data covering the period 1980–1997.ResultsAge-adjusted suicide rates among Turks were lower than among Germans (relative risk 0.3). Among Turkish girls and young women under 18xa0years, however, the relative risk compared to Germans was 1.8 (95% confidence interval 1.4–2.3). The male-to-female ratio in this age group was 3.2 among Germans and 0.6 among Turks.DiscussionOverall, Turks living in Germany have a lower suicide mortality than Germans. Possible explanations include a high level of social coherence in the Turkish community and religious prohibitions. The high suicide rate among Turkish girls and young women could indicate the presence of social or cultural conflict situations.

Combining a name algorithm with a capture–recapture method to retrieve cases of Turkish descent from a German population-based cancer registry

An increasing proportion of the 2 million Turkish residents in Germany is reaching the age in which cancer becomes a common health problem. However, data on cancer incidence and survival among Turkish residents are lacking due to incomplete reporting of nationality in German cancer registries. In the population-based cancer registry of the Saarland, retrieval by reported nationality yielded only 38% (95% confidence interval (CI): 31-45%) of the estimated number of Turkish cases in the registry; furthermore, nationality information was found to be inaccurate, and completeness dependent on the vital status of cases. A newly developed algorithm based on family names retrieved 85% (95% CI: 79-90%) of Turkish cases. Combining the two sources in a capture-recapture approach yielded 91% (95% CI: 86-94%) of the estimated total number of Turkish cases. Hence, the name-based algorithm provides a new and attractive tool for valid registry-based cancer research among Turks in Germany.

Imaging Studies in Metastatic Urogenital Cancer Patients Undergoing Systemic Therapy: Recommendations of a Multidisciplinary Consensus Meeting of the Association of Urological Oncology of the German Cancer Society

Introduction: Imaging studies are an integral and important diagnostic modality to stage, to monitor and follow-up patients with metastatic urogenital cancer. The currently available guidelines on diagnosis and treatment of urogenital cancer do not provide the clinician with evidence-based recommendations for daily practice. Objectives: To develop scientifically valid recommendations with regard to the most appropriate imaging technique and the most useful time interval in metastatic urogenital cancer patients undergoing systemic therapy. Methods: A systematic literature review was performed searching MedLine, Embase and Web of Science databases using the terms prostate, renal cell, bladder and testis cancer in combination with the variables lymph node, lung, liver, bone metastases, chemotherapy and molecular therapy, and the search terms computed tomography, magnetic resonance imaging and positron emission tomography were applied. A total of 11,834 records were retrieved from all databases. The panel reviewed the records to identify articles with the highest level of evidence using the recommendation of the US Agency for Health Care Policy and Research. Conclusions: Contrast-enhanced computed tomography remains the standard imaging technique for monitoring of pulmonary, hepatic and lymph node metastases. Bone scintigraphy is still the most widely used imaging technique for the detection and follow-up of osseous lesions. For clinical trials it might be replaced by either PET-CT or MRI of the skeletal axis. Response assessment for patients treated with cytotoxic regime is best performed by the RECIST/WHO criteria; treatment response to molecular triggered therapy is best assessed by CT evaluating decrease in tumor size and density. Cross-sectional imaging studies for response assessment might be obtained after each 2 cycles of systemic therapy to early stratify responders from non-responders.