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Biomedical subjects

K Straif

Publications and source records attributed to K Straif.

At least 19 recordsLinked to original sources
PubMed2006

Cancer mortality in German carbon black workers 1976-98.

BACKGROUND: Few studies have investigated cancer risks in carbon black workers and the findings were inconclusive. METHODS: The current study explores the mortality of a cohort of 1535 male German blue-collar workers employed at a carbon black manufacturing plant for at least one year between 1960 and 1998. Vital status and causes of death were assessed for the period 1976-98. Occupational histories and information on smoking were abstracted from company records. Standardised mortality ratios (SMR) and Poisson regression models were calculated. RESULTS: The SMRs for all cause mortality (observed deaths (obs) 332, SMR 120, 95% CI 108 to 134), and mortality from lung cancer (obs 50, SMR 218, 95% CI 161 to 287) were increased using national rates as reference. Comparisons to regional rates from the federal state gave SMRs of 120 (95% CI 107 to 133) and 183 (95% CI 136 to 241), respectively. However, there was no apparent dose response relationship between lung cancer mortality and several indicators of occupational exposure, including years of employment and carbon black exposure. CONCLUSIONS: The mortality from lung cancer among German carbon black workers was increased. The high lung cancer SMR can not fully be explained by selection, smoking, or other occupational risk factors, but the results also provide little evidence for an effect of carbon black exposure.

Adult↗
PubMed2005

[Smoking as potential confounder in german epidemiological studies: standardization of assessment, quantification, and analysis].

Tobacco smoking is one of the most frequently examined risk factors in epidemiological studies due to the high frequency of smoking in the population and its high risk potential. This paper discusses the issue of standardization of the assessment of tobacco exposure in German epidemiological studies based on a suggestion of the working group "Epidemiological methods" of the German Society of Epidemiology (DGEpi), the German Society of Social Medicine and Prevention (DGSMP), and German Society of Medical Informatics, Biometry and Epidemiology (GMDS) together with the working group "Epidemiology in the workplace" of the DGEpi and the German Society of Occupational and Environmental Medicine (DGAUM). The main element is a short questionnaire for German adults for the assessment of tobacco smoking in epidemiological studies where smoking is a potential confounder. In addition, information on the consideration of intermittent periods of non-smoking, a very short questionnaire for medical examinations in the workplace or non-responder interviews as well as the quantification and statistical modelling of smoking are presented. A brief discussion of scientific problems and questionnaires related to the exposure to environmental tobacco smoke is given.

Bias↗
PubMed2004

Tobacco smoking and cancer: a brief review of recent epidemiological evidence.

This report summarises the epidemiological evidence on the association between tobacco smoking and cancer, which was reviewed by an international group of scientists convened by IARC. Studies published since the 1986 IARC Monograph on "Tobacco smoking" provide sufficient evidence to establish a causal association between cigarette smoking and cancer of the nasal cavities and paranasal sinuses, nasopharynx, stomach, liver, kidney (renal cell carcinoma) and uterine cervix, and for adenocarcinoma of the oesophagus and myeloid leukaemia. These sites add to the previously established list of cancers causally associated with cigarette smoking, namely cancer of the lung, oral cavity, pharynx, larynx, oesophagus, pancreas, urinary bladder and renal pelvis. Other forms of tobacco smoking, such as cigars, pipes and bidis, also increase risk for cancer, including cancer of the lung and parts of the upper aerodigestive tract. A meta-analysis of over 50 studies on involuntary smoking among never smokers showed a consistent and statistically significant association between exposure to environmental tobacco smoke and lung cancer risk. Smoking is currently responsible for a third of all cancer deaths in many Western countries. It has been estimated that every other smoker will be killed by tobacco.

Humans↗
PubMed2000

Exposure to nitrosamines, carbon black, asbestos, and talc and mortality from stomach, lung, and laryngeal cancer in a cohort of rubber workers.

There is sufficient evidence for an excess occurrence of stomach and lung cancer among rubber workers. However, evidence for causal associations with specific exposures is still limited. A cohort of 8,933 male German rubber workers was followed for mortality from January 1, 1981 through December 31, 1991. Work histories were reconstructed using routinely documented cost center codes. For each cost center code, calendar time-and plant-specific levels of exposure to nitrosamines, asbestos, talc (low, medium (m), and high (h)), and carbon black (two levels) were estimated by industrial hygienists. Rate ratios (RR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards models, with the lowest exposure level used as the reference category. Exposure was lagged 10 years to account for latency. Exposure-response relations between exposure to asbestos and lung cancer mortality (RRm = 1.3, 95% CI: 0.9, 1.9; RRh = 2.0, 95% CI: 0.9, 4.1) and between exposure to dust (talc and asbestos combined) and stomach cancer mortality (RRm = 1.8, 95% CI: 0.9, 3.8; RRh = 2.7, 95% CI: 1.0, 7.1) were observed. Exposure to nitrosamines was not associated with mortality from stomach or lung cancer. These results suggest that the increased mortality from lung and stomach cancer among rubber workers is associated with exposure to asbestos and dust, respectively.

Aged↗
PubMed2000

A stand-alone windows applications for computing exact person-years, standardized mortality ratios and confidence intervals in epidemiological studies.

We introduce a stand-alone and user-friendly person-years and mortality computation program (PAMCOMP) for calculating exact person-years and standardized mortality and incidence ratios running under Windows 95/98 and NT. The calculation of person-years allows flexible stratification by self-defined and unrestricted categories of age and calendar years. Furthermore, it is possible to lag person-years to account for latency periods. The standardized mortality ratio computation includes calculation of 90%, 95%, and 99% confidence intervals. Import and export filters for standard personal computer file formats are available. The software is free of charge and can be downloaded from: http://medweb.uni-muenster.de/institute/epi/ pamcomp/pamcomp.html

Cohort Studies↗
PubMed2000

Exposure to high concentrations of nitrosamines and cancer mortality among a cohort of rubber workers.

OBJECTIVES: To examine if the occurrence of different cancers was increased among rubber workers, as the highest known exposures of humans to nitrosamines have occurred in the rubber industry. METHODS: A cohort of 8933 rubber workers (hired after 1 January 1950, still active or retired on 1 January 1981 and employed for at least 1 year in one of five study factories) was followed up for mortality from 1 January 1981 to 31 December 1991. Work histories were reconstructed with routinely documented cost centre codes, which allowed identification by employment in specific work areas. For each cost centre code time and factory specific, semi-quantitative exposures to nitrosamines (three levels: low, medium, high) and other compounds were estimated by industrial hygienists. Rate ratios for medium (RRm) and high (RRh) exposures and 95% confidence intervals (95% CIs) were calculated with Cox's proportional hazards models with the low exposure as reference. RESULTS: Exposure to nitrosamines was significantly associated with an increased mortality from cancers of the oesophagus (13 deaths: RRm 1.7, 95% CI 0.3 to 10.3; RRh 7.3, 95% CI 1.9 to 27.8) and of the oral cavity and pharynx (17 deaths: RRm 0.8, 95% CI 0.2 to 4.1; RRh 3.9, 95% CI 1.4 to 11.1). A non-significant trend of increasing mortality with exposure to higher concentrations of nitrosamines was found for mortality from cancer of the prostate (26 deaths: RRm 1.4, 95% CI 0.5 to 3.8; RRh 2.2, 95% CI 0.9 to 5.6), and the brain (six deaths: RRm 3.9, 95% CI 0.3 to 42.6; RRh 6.0, 95% CI 0.6 to 57.6). No association was found between exposure to nitrosamines and cancer of the stomach (RRm 0.8, 95% CI 0.4 to 1.8; RRh 1.2, 95% CI 0.5 to 2.5) or lung (RRm 1.0, 95% CI 0.6 to 1.5; RRh 1.0, 95% CI 0.7 to 1.6). CONCLUSIONS: Exposure to high concentrations of nitrosamines is associated with increased mortality from cancers of the oesophagus, oral cavity, and pharynx, but not with increased mortality from cancers of the stomach or lung.

Adult↗
PubMed1999

Elevated mortality from nonalcohol-related chronic liver disease among female rubber workers: is it associated with exposure to nitrosamines?

BACKGROUND: Despite several case reports describing liver toxicity of nitrosamines and the fact that some N-nitroso compounds are used to induce cirrhosis of the liver in animal models, this association has not been investigated in epidemiological studies. METHODS: A cohort of 2,875 female rubber workers who were active on January 1, 1976, or hired thereafter, and who had been employed for at least 1 year in one of five plants producing tires or technical rubber goods was followed for mortality from January, 1976, through December, 1991. Work histories were reconstructed using routinely documented "cost center codes" and classified into six work areas. Age and calendar year standardized mortality ratios (SMR) and 95% confidence intervals (95% CI) were calculated and stratified by plant, work area, year of hire, and years of employment in the respective work area. RESULTS: The excess mortality from cirrhosis of the liver was most pronounced for nonalcohol-related cirrhosis of the liver (ICD-9 571.4-571.9: 10 deaths, SMR 202; 95% CI 97-372). Mortality from alcohol-related cirrhosis of the liver (ICD-9 571.0-571.3: 3 deaths, SMR 153; 95% CI 31-446) and from other alcohol-related diseases (organic psychoses, injury, and poisoning) was not statistically significantly elevated. All 10 cases of nonalcohol-related cirrhosis had worked in production of technical rubber goods (SMR 279; 95% CI 134-514) and risks increased with earlier years of hire and with longer duration of employment in this work area. DISCUSSION: Although our results must be interpreted with caution, they suggest that the observed excess deaths from cirrhosis of the liver are associated with occupational risk factors. In light of additional evidence from case reports and animal data, exposure to nitrosamines may be a plausible risk factor for the observed excess mortality.

Adult↗
PubMed1999

Occupational risk factors for mortality from stomach and lung cancer among rubber workers: an analysis using internal controls and refined exposure assessment.

OBJECTIVES: To determine occupational risk factors for stomach and lung cancer among workers in the German rubber industry. METHODS: A cohort of all male German rubber workers (n = 11,633) who had been employed for at least one year in one of five study plants and who were alive and actively employed or retired on 1 January 1981 was followed for mortality from 1 January 1981 through December 1991. A subcohort of n = 8,933 workers who were hired after 1 January 1950 was defined to focus on working conditions in the more recent rubber industry. Work histories were reconstructed using routinely documented 'cost centre codes' and classified into six work areas as well as subgroups of some work areas. The work areas are: 1. preparation of materials, 2. production of technical rubber goods, 3. production of tyres, 4. storage and dispatch, 5. maintenance, 6. others. Standardized mortality ratios (SMR) and Cox proportional hazards models were calculated for each of the work areas (>1 year of employment in the respective work area). Hazard rate ratios were adjusted for age (time marker) and stratified for year of hire (1950-1959, > or =1960) and years of employment in the respective work area (1-9 years, > or =10 years); years of employment were lagged 10 years to account for latency. RESULTS: Compared to the national reference population mortality from cancer of stomach (observed 44, SMR = 117; 95% CI: 85-157) and lung (observed 154, SMR = 123; 95% CI: 104-144) was slightly increased. Using internal controls we observed excess deaths from stomach cancer in work area 1 (relative risk [RR] = 2.3; 95% CI: 1.2-4.2) and from lung cancer in work areas 1 (RR = 1.7; 95% CI: 1.2-2.3), 2 (RR = 1.5; 95% CI: 1.1-2.1), and 3 (RR = 1.3; 95% CI: 0.9-1.8). On the basis of cumulative years of employment an exposure response relationship was observed for mortality from both cancer sites among a subcategory of work area 1: weighing and mixing. Increased risks were also seen for lung cancer among workers employed in production of technical rubber goods. CONCLUSION: Our results support an association between an excess mortality from stomach and lung cancer and employment in early production stages of rubber manufacturing, especially weighing and mixing. This may point to an aetiologic role of asbestos or carbon black. For stomach cancer additional risk factors, e.g. exposure to dust and talc, deserve further investigation. The results of the present study do not support a causal role of nitrosamines for stomach or lung cancer.

Case-Control Studies↗
PubMed1999

An occupational cohort mortality study of women in the German rubber industry: 1976 to 1991.

Few previous studies of workers in the rubber industry have focused on women. We examined patterns of mortality among 2871 women employed in one of five German rubber plants for at least 1 year on or after January 1, 1976, and observed through December 31, 1991. All-causes mortality was near that expected (standardized mortality ratio [lsqbSMR], 101; 95% confidence interval [CI], 87 to 118), but cancer mortality was decreased (SMR, 90; 95% CI, 70 to 115). Nevertheless, excesses were observed for mortality from stomach cancer (SMR, 156; 95% CI, 63 to 322), lung cancer (SMR, 140; 95% CI, 56 to 289), and lymphatic system cancers (SMR, 175; 95% CI, 48 to 448). Stronger associations were observed among sub-cohorts defined by time period hired. Despite limited numbers of deaths, modest excesses of mortality due to specific cancers were observed and are consistent with previous studies.

Adult↗
PubMed1998

Workplace risk factors for cancer in the German rubber industry: Part 1. Mortality from respiratory cancers.

OBJECTIVES: To determine the cancer specific mortality by work area among active and retired male workers in the German rubber industry. METHODS: A cohort of 11,663 male German workers was followed up for mortality from 1 January 1981 to 31 December 1991. Cohort members were classified as active (n = 7536) or retired (n = 4127) as of 1 January 1981 and had been employed for at least one year in one of five study plants producing tyres or technical rubber goods. Work histories were reconstructed with routinely documented "cost centre codes" which were classified into six categories: I preparation of materials; II production of technical rubber goods; III production of tyres; IV storage and dispatch; V maintenance; and VI others. Standardised mortality ratios (SMRs) adjusted for age and calendar year and 95% confidence intervals (95% CIs), stratified by work area (employment in respective work area for at least one year) and time related variables (year of hire, lagged years of employment in work area), were calculated from national reference rates. RESULTS: SMRs for laryngeal cancer were highest in work area I (SMR 253; 95% CI 93 to 551) and were significant among workers who were employed for > 10 years in this work area (SMR 330; 95% CI 107 to 779). Increased mortality rates from lung cancer were identified in work areas I (SMR 162; 95% CI 129 to 202), II (SMR 134; 95% CI 109 to 163), and V (SMR 131; 95% CI 102 to 167). Mortality from pleural cancer was increased in all six work areas, and significant excesses were found in work areas I (SMR 448; 95% CI 122 to 1146), II (SMR 505; 95% CI 202 to 1040), and V (SMR 554; 95% CI 179 to 1290). CONCLUSION: A causal relation between the excess of pleural cancer and exposure to asbestos among rubber workers is plausible and likely. In this study, the pattern of excess of lung cancer parallels the pattern of excess of pleural cancer. This points to asbestos as one risk factor for the excess deaths from lung cancer among rubber workers. The study provides further evidence for an increased mortality from laryngeal cancer among workers in the rubber industry, particularly in work area I.

Adult↗
PubMed1998

Workplace risk factors for cancer in the German rubber industry: Part 2. Mortality from non-respiratory cancers.

OBJECTIVES: To determine the mortality from non-respiratory cancers by work area among active and retired male workers of the German rubber industry. METHODS: A cohort of 11,633 male German workers was followed up for mortality from 1 January 1981 to 31 December 1991. Cohort members were active (n = 7536) or retired (n = 4127) on 1 January 1981 and had been employed for at least one year in one of five study plants producing tyres or technical rubber goods. Work histories were reconstructed from routinely documented "cost centre codes" and classified into six categories: I preparation of materials; II production of technical rubber goods; III production of tyres; IV storage and dispatch; V general service; VI others. Standardised mortality ratios (SMRs) and 95% confidence intervals (95% CIs), controlling for age and calendar year and stratified by work area (employment in respective work area for at least one year) and time related variables (year of hire, lagged years of employment in work area) were calculated from national mortality rates as the reference. RESULTS: Significant increases in mortality were found for pharyngeal cancer in work area IV (three deaths, SMR 486, 95% CI 101 to 1419), oesophageal cancer in work area III (11 deaths, SMR 227, 95% CI 114 to 407), and leukaemia in work areas I (11 deaths, SMR 216; 95% CI 108 to 387) and II (14 deaths, SMR 187; 95% CI 102 to 213). Furthermore, increased SMRs were found for stomach cancer in work area I (22 deaths, SMR 134; 95% CI 84 to 203), colon cancer in work area II (27 deaths, SMR 131, 95% CI 86 to 191), prostatic cancer in work area V (27 deaths, SMR 152, 95% CI 99 to 221), and bladder cancer in work areas IV (six deaths, SMR 253; 95% CI 93 to 551) and V (12 deaths, SMR 159, 95% CI 82 to 279). Mortality from cancer of the liver or gall bladder, pancreas and kidney, and from lymphomas was not substantially increased in any of the work areas. CONCLUSIONS: Mortality from cancer of several sites was associated with specific work areas. Some of these associations have been reported previously. Future analyses of our study will have to determine the role of specific exposures in the aetiology of these cancers.

Adult↗
PubMed1997

Comparison of U.S. Occupational Safety and Health Administration standards and German Berufsgenossenschaften Guidelines for Preventive Occupational Health Examinations.

Thirty-three U.S. Occupational Safety and Health Administration (OSHA) standards contain mandated medical service provisions. The German Berufsgenossenschaften Guidelines for Preventive Occupational Health Examinations currently comprise 38 guidelines, which contain mandated medical service provisions. Based on a previously published method for scoring several medical program elements, the Berufsgenossenchaften guidelines were compared with the OSHA standards. Specific program elements were combined to generate and compare quality control scores, screening scores and surveillance scores. The asbestos standard/guidelines were compared in more detail (e.g., physical examination, laboratory tests, examination schedule, eligibility). The German medical requirements consistently ranked higher than their U.S. counterparts for overall scores and the scoring indices for quality control, screening, and surveillance. However, this comparison also reveals that few surveillance features have been incorporated into the medical requirements of either country, suggesting that neither country is making full use of workplace medical services for primary prevention.

Asbestos↗