Vegetarian diets and colon cancer: the German experience.

The study assessed mortality and morbidity risks as related to nutritional status of moderate and strict vegetarians in Germany. The total cohort of 1904 self-identified persons was followed up for 11 y. Compared with national mortality rates for Federal Republic of Germany, the observed deaths for all causes were below expectation by a factor of 0.44 for men and 0.53 for women. The mortality for colon cancer was reduced [standardized mortality ration (SMR 44.1 for men and 77.9 for women]. No deaths were observed from rectal cancer. A vegetarian lifestyle of long duration (> or = 20 y) was associated with decreased overall and cancer mortality. Other determinants of decreased cause-specific mortality were physical activity, body weight, and strictness of adherence to the life-style. The relationship between a vegetarian and fiber-rich diet and a decreased risk for colon cancer has been reported in many studies. In this study, the influence of other factors such as health-conscious behavior and a healthy lifestyle seem to indicate partly stronger effects than nutrition itself. This may explain the generally better health of moderate vegetarians.

Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies.

We combined data from 5 prospective studies to compare the death rates from common diseases of vegetarians with those of nonvegetarians with similar lifestyles. A summary of these results was reported previously; we report here more details of the findings. Data for 76172 men and women were available. Vegetarians were those who did not eat any meat or fish (n = 27808). Death rate ratios at ages 16-89 y were calculated by Poisson regression and all results were adjusted for age, sex, and smoking status. A random-effects model was used to calculate pooled estimates of effect for all studies combined. There were 8330 deaths after a mean of 10.6 y of follow-up. Mortality from ischemic heart disease was 24% lower in vegetarians than in nonvegetarians (death rate ratio: 0.76; 95% CI: 0.62, 0.94; P<0.01). The lower mortality from ischemic heart disease among vegetarians was greater at younger ages and was restricted to those who had followed their current diet for >5 y. Further categorization of diets showed that, in comparison with regular meat eaters, mortality from ischemic heart disease was 20% lower in occasional meat eaters, 34% lower in people who ate fish but not meat, 34% lower in lactoovovegetarians, and 26% lower in vegans. There were no significant differences between vegetarians and nonvegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, lung cancer, breast cancer, prostate cancer, or all other causes combined.

Updating lung cancer mortality among a cohort of man-made mineral fibre production workers in seven European countries.

A historical cohort of 21,967 workers ever employed in 13 European factories manufacturing various types of man-made mineral fibres (MMMF) was observed until 1982. Overall there were 2719 deaths (standardised mortality ratio (SMR) = 111) of which 189 were from lung cancer (SMR = 125). For the glasswool and rockwool/slagwool production subcohorts the lung cancer SMRs rose with time since first exposure, exceeding 170 for the period of 30 or more years. Adjustment for regional variations in mortality substantially reduced the excess in the glasswool group, but not in the rockwool/slagwool. In neither subgroup was there any relationship of lung cancer mortality with length of employment. During the early years of rockwool/slagwool production there was the potential for much higher fibrous dust exposure than at present, because of the absence of dust suppressing oil and/or the use of a batch production process. In addition slag was widely used as a raw material. Amongst workers employed during the early phase, there were 10 lung cancer deaths giving SMRs of 270 and 244 for the periods 20-29 and 30 or more years since first exposure. This group accounts for most of the absolute excess of lung cancer for the rockwool/slagwool plants.

Regional risk factors for stomach cancer in the FRG.

A multicentric, hospital-based, case-control study was conducted in high- and low-risk areas for stomach cancer in the Federal Republic of Germany, by which means a low intake of dietary vitamin C (relative risk [RR] = 2.32, 95% confidence interval [CI] 1.22-4.43 for lowest against highest quintile), noncentralized water supply (RR = 2.17, CI 1.14-4.13 against central water supply), refrigerator use for less than 25 years (RR = 1.33, CI 0.82-2.15 against more than 30 years), and the use of spruce for smoking meat at home (RR = 3.33, CI 1.56-7.12 against not smoking meat at home), were identified as factors potentially causally related to stomach cancer occurrence. The attributable risk for gastric carcinoma among the population (AR) was 37.5% for low vitamin C intake, 37.2% for noncentralized water supply, 10.6% for late refrigerator use, and 4.15% for use of spruce for smoking meat at home in this analysis. The overall ARp amounted to 68.3%. These personally linked factors also showed a strong regional distribution, in that the low-risk area had more favorable categories of exposure. Traditional nutritional habits around 1910 were recorded during a survey by ethnologists in 1965. This material was used to contrast those in high and low stomach cancer risk areas with the habits in the south of Germany in general. Vegetable use was most common in the low-risk area, whereas mashed potatoes, cabbage, and farinaceous dishes dominated in the high-risk area. Tomatoes were introduced several years later into the high-risk area, both in terms of consumption and cultivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary and lifestyle determinants of mortality among German vegetarians.

Lifestyle characteristics of a cohort of 1904 Germans adhering mainly to a vegetarian diet were examined in relation to their mortality after 11 years of follow-up. Poisson regression modelling was performed to consider the simultaneous effects of different variables on mortality from all causes, cancer (ICD 140-208) and cardiovascular diseases (ICD 390-459). Compared to a low level of self-reported physical activity, those with a medium or high level of activity experienced only half the mortality from all causes and from cardiovascular diseases. Physical activity showed no beneficial effect for cancer mortality in this cohort. The body mass index (BMI) was an independent risk factor for mortality among men but essentially unrelated to mortality among women. Those in the middle third of the BMI distribution experienced the lowest mortality. A negative association between BMI and cancer mortality lost statistical significance when the first 5 years of follow-up were deleted, suggesting that a lower BMI was a consequence of prevalent disease. Both the duration of vegetarianism and the vegetarian status (strict versus moderate) showed a moderate effect on all cause and cancer mortality. A longer duration of vegetarianism (> or = 20 years) was associated with a lower risk, pointing to a real protective effect of this lifestyle. A lower risk of death among moderate vegetarians suggests that sound nutritional planning may be more important than absolute avoidance of meat.

Comparison of information on occupation and lifestyle habits obtained from European man-made vitreous fibre production workers and their relatives.

BACKGROUND: Studies of the aetiology of fatal diseases often rely on data obtained from relatives, which can cause loss of precision and introduce bias. We assessed the quality of such information on demographics, occupation, smoking and alcohol habits. METHODS: We compared contemporary interviews, based on a structured questionnaire, with male workers from the man-made vitreous fibre production industry in four European countries and their relatives. The participation rate was 63% (74 pairs of workers and relatives). RESULTS: Only minor differences in the ability to answer the questions appeared among workers and relatives, except for specific occupational questions. There was moderate to excellent agreement for demographics, residential and work history (kappa or intraclass correlation range: 0.44-0.98). For smoking habits, beer and wine consumption the agreement was good to excellent (range: 0.59-0.99). In particular, number of different residential areas, jobs, industries, and duration of wine drinking were significantly underreported by the relatives. No general determinant for reduced agreement appeared. CONCLUSIONS: In general, the quality of information obtained from relatives appeared good. However, information on specific occupational exposures may be improved by supplementing the information from relatives with details obtained from colleagues, occupational hygiene experts or occupation-exposure matrices.

Lung cancer mortality of workers employed in chromate pigment factories. A multicentric European epidemiological study.

This study was designed in an attempt to quantify the mortality from cancer and other diseases among workers of European factories producing chromate pigments. The prevailing mixed exposures to zinc as well as lead chromate pigment--although the latter was produced predominantly over the whole period of time made it impossible to distinguish those persons exposed to lead chromate pigment. This report deals with cancer of the respiratory tract and lung cancer in particular. The total workforce of each factory included in the study was followed up, more successfully when they were employed before 1960 than after that time owing to the rising number of foreign nationals. Observed deaths from five factories were compared with expected deaths calculated on the basis of mortality figures for the region in which a given factory was located. Further analysis concerned data of relevant cohorts, which comprised only persons observed for a minimum of 10 years (i.e., exposure beginning before 1965), certainty of complete records for the entire staff to assure a complete cohort instead of prevailing healthy survivors, and exclusion of all foreign nationals. As a result, the overall mortality did not deviate from the expected rates. Lung-cancer rates were always in excess of expected numbers, although only in one cohort to a statistically significant extent. The pattern of duration of exposure indicates that the lung-cancer risk does not show a clear dose-response effect with time of employment. Due to the mixed nature of exposure, conclusions must be limited with the effect that the results obtained are consistent with the hypothesis that working in a chrome-processing plant environment is associated with an increased incidence of lung cancer and with a higher probability of dying from lung cancer compared with the general population.

The epidemiology of stomach cancer in Bavaria.

Stomach cancer represents an important cause of death in the Federal Republic of Germany, the regional analysis of mortality rates showing that the rates in Bavaria lay significantly above the national average during the years 1952 till 1978. Within this Federal State the mortality again is not uniform but regions in the Northeast with high rates are distinguishable from low mortality in the Southwest. Furthermore, the analysis by age and birth cohorts shows a decrease of mortality from stomach cancer with later years of birth. The considerable differences in consecutive birth cohorts, given the regional patterns, may indicate a varying exposure to etiological factors, most likely to be sought in the early life of the later cancer victims. In an attempt to clarify the reasons for these regional particularities a case-control study is designed to investigate, among other factors, the etiological relevance of nutritional habits. The possible influence of competing causes of death is discussed.

Common infections in the history of cancer patients and controls.

The association between the frequency of manifest infectious diseases and cancer risk was investigated in a case-control study at Heidelberg, FRG. A total of 255 cases with carcinomas of the stomach, colon, rectum, breast, and ovary, as well as 255 population controls and 230 hospital controls were interviewed using a standard questionnaire. Controls were matched to the cases for age, sex, and region of residence at the time of the interview. A history of common colds or gastroenteric influenza prior to the interview was found to be associated with a decreased cancer risk. Thus the odds ratios for "three or more common colds per year (on average)" versus "no common cold within the last 5 years prior to the interview" were 0.18 (95% CI = 0.05-0.69) and 0.23 (95% CI = 0.06-0.89) relative to population controls and hospital controls, respectively. There was no apparent relationship between childhood infections or other diseases reported in the earlier history, and cancer risk. While the findings are supported by previous studies and fit well into the results of other fields of cancer research, a conclusive interpretation and biological explanation cannot yet be given.

Challenges to environmental toxicology and epidemiology: where do we stand and which way do we go?

Modern toxicology investigates a wide array of both old and new health hazards. Priority setting is needed to select agents for research from the plethora of exposure circumstances. The changing societies and a growing fraction of the aged have to be taken into consideration. A precise exposure assessment is of importance for risk estimation and regulation. Toxicology contributes to the exploration of pathomechanisms to specify the exposure metrics for risk estimation. Combined effects of co-existing agents are not yet sufficiently understood. Animal experiments allow a separate administration of agents which can not be disentangled by epidemiological means, but their value is limited for low exposure levels in many of today's settings. As an experimental science, toxicology has to keep pace with the rapidly growing knowledge about the language of the genome and the changing paradigms in cancer development. During the pioneer era of assembling a working draft of the human genome, toxicogenomics has been developed. Gene and pathway complexity have to be considered when investigating gene-environment interactions. For a best conduct of studies, modern toxicology needs a close liaison with many other disciplines like epidemiology and bioinformatics.

The chromosome-based challenge assay using fluorescence in situ hybridization: a possible test for increased cancer susceptibility.

UNLABELLED: The challenge assay is a cytogenetic approach to measure the repair competence of cells. For in vitro studies, human lymphocytes are exposed to different substances and are irradiated simultaneously. To investigate subjects exposed occupationally or environmentally, untreated blood samples are directly irradiated without any further treatment. Certain substances like heavy metals reveal carcinogenic potential without well defined mechanism of action. While they are not mutagenic they may have an effect on DNA repair capacity. The challenge assay was successfully applied in vitro experiments with cadmium to detect an interaction of this heavy metal with the repair of X-ray-induced chromosome breaks. CdCl(2) alone had no effect on the formation of chromosome aberrations (CA), not even in the cytotoxic concentration (50 microM). However, cadmium showed an effect on the number of chromosomal rearrangements (CR) after X-ray challenge. For 0.5 microM CdCl(2), CA frequencies were significantly elevated compared to the rates for X-rays alone. For the two higher concentrations the rates showed a slight additional increase. Hence, the challenge assay appears suitable to test for chromosomal sensitivity induced by toxicants. Subsequently, a study of styrene exposed workers was initiated to address the question whether styrene exposure has an influence on the DNA repair. In addition, we investigated whether a polymorphism of genes coding for phase II detoxifying enzymes glutathione-S-transferases GSTM1 and GSTT1 had an influence on chromosomal sensitivity. First and preliminary data are presented. While there is a correlation of the rate of CR with cumulative lifetime exposure of styrene, the most recent styrene exposure had no effect. 'At risk' genotypes with higher incidence of CA could not be identified at this stage of the ongoing study. CONCLUSION: the challenge assay is able to detect enhanced susceptibility for CR caused by genetic predisposition for DNA repair deficiency. Our data indicate that environmental or occupational exposure to certain substances can interfere with DNA repair processes. As the process of induction of CR is associated with carcinogenesis, the challenge assay may provide a valuable biomarker for cancer epidemiology studies.

Changes in degree of sclerosis as a function of prophylactic treatment in cancer-prone and CHD-prone probands.

One-hundred and ninety-two probands were selected on the basis of personality questionnaires as being cancer-prone (100) or CHD-prone (92). They were then randomly divided into a control and a treatment group, the latter receiving a special kind of behaviour therapy attempting to change the personality patterns in the direction of a healthier, more autonomous personality. Follow-up after 10 and 13 years disclosed significantly lower death rates in probands receiving prophylactic treatment than in controls. Of special interest was the degree of sclerosis in the fundus of the eye, rateds on a 3-point scale. This was significantly higher prior to therapy in the CHD-prone group than in the cancer-prone group. Treatment reduced the degree of sclerosis, particularly in the CHD group; lack of treatment was followed by an increase in sclerosis. Similar but less marked changes were found in the cancer-prone group. Clearly psychological treatment affects significantly bodily functions associated with CHD. Other risk factors considered were systolic and diastolic blood pressure, blood cholesterol and blood sugar, all of which, together with personality, influenced the degree of sclerosis observed.

Mortality of short-term workers in two international cohorts.

The purpose of this study was to compare the pattern of mortality of blue-collar workers employed less and more than 1 year in the man-made vitreous fiber (MMVF) and the reinforced plastic industries, the latter group being exposed to styrene. We conducted an analysis among 21,784 workers with less than 1 year of employment (short-term workers) and 19,117 workers with 1 or more years of employment (long-term workers) employed in eight European countries. We conducted analyses based on external as well as internal comparisons. In both cohorts, the standardized mortality ratio for all causes among short-term workers was approximately 40% higher, compared with that for longer-term workers. In internal comparisons, the difference was reduced to 9% in the MMVF cohort and 11% in the styrene cohort. Workers with less than 1 month of employment displayed an increased mortality in both cohorts and in most countries. The increased mortality among short-term workers was not concentrated shortly after they quit employment. In both cohorts, short-term workers had a higher mortality from external causes, while little difference was seen in mortality from ischemic heart disease and malignant neoplasms. Although extra-occupational factors may contribute to increase the mortality of short-term workers and, in particular, of those employed for less than 1 month, the difference observed in analyses adjusted for characteristics of employment suggested a relatively small difference in mortality from most causes.

The importance of epidemiology in the study of causes of bone tumours.

Research into the causes of disease in human populations makes use of epidemiological methods for recognizing avoidable risk factors which may be active prior to the occurrence of malignant tumours. With the exception of the risks or irradiation, the aetiology of bone tumours remains unclear, and it is particularly striking that in the literature to date and in a survey of research currently in progress there are no epidemiological studies which involve other than radiation-exposed populations. This is the reason why it has only been possible to obtain initial suggestions of potential areas of risk from ecologic correlations based on the evaluation of mortality and morbidity rates with respect to environmental factors. Several results obtained from systematic comparisons of mortality in the countries of the world and two correlative relationships are reported, and the difficulties in interpreting the results are discussed. Population-based registration of bone tumours and case-control studies based on registries are recommended.

Mortality of workers in a German rock-wool factory--a second look with extended follow-up.

A cohort of 2,092 workers employed in a German rock-wool factory was followed until the end of 1982, and the mortality experience was compared with the national mortality rates and the rates of an internal reference cohort. This mortality analysis revealed a standardized mortality ratio (SMR) of 110 for overall mortality. Significantly more malignant neoplasms occurred than were expected (SMR 127). The increase in risk for lung cancer (SMR 121), which was not statistically significant, was also not related to time since first exposure or length of employment. The occurrence of an unusually high SMR of 336 for benign and unspecified neoplasms could not be clarified. Most of the excess from other specific causes of death, such as stomach cancer, pancreatic cancer, and alcoholism, appear to be unrelated to the rock-wool production since they occurred either among workers employed for very short periods (less than one year) or as frequently among workers in the reference cohort.

A mortality study of workers employed in a German rock wool factory.

As part of a coordinated European study including 13 plants, 2,096 workers employed in rock wool production, packing, and maintenance activities in a German factory were followed until 1979 for cause-specific mortality. There were no consistent differences between the observed and expected deaths in the study cohort on the basis of the experience of the general population. The separate analysis of persons engaged in rock wool production and packing and those engaged in maintenance yielded an excess of lung cancer deaths with borderline significance for occurrence among the maintenance workers and an elevation in standardized mortality ratio for stomach cancer related to time since first employment in the production group. Comparison with a factory-based reference cohort did not show any increased health risk for the exposed cohort. An extension of the follow-up for five years is planned in an attempt to clarify the present findings.

Cancer risk of arc welders exposed to fumes containing chromium and nickel.

A retrospective follow-up study among chromium- and nickel-exposed welders, which took into consideration welding procedures, duration of exposure, and smoking habits, yielded an increased cancer risk in a comparison with an internal reference group of turners, milling cutters, and drillers, as well as in a comparison with the general population of the Federal Republic of Germany. Due to the cohort size (1 224 welders, 1 694 turners) and the fact that the observation period is still too short, confirmed statements as to the target cancer sites cannot yet be made. However, it emerges that welding with coated electrodes shows a higher cancer risk as compared to the other welding processes observed. This finding may be explained by the fact that the share of hexavalent chromium compounds in the welding fumes is greater with coated electrodes than with other processes so that a follow-up study observing the health risks of chromium and nickel fumes separately would be warranted. For the confirmation of a more favorable outcome with gas-shielded welding, a larger investigation group or a longer observation period would be required.

Survey of mortality among employees engaged in the manufacture of styrene and polystyrene at the BASF Ludwigshafen works.

A mortality survey of 1,960 employees currently or previously exposed to styrene at work has shown that the observed number of deaths from cancer or other causes is no higher than the number expected in the German population or in a group of BASF employees. Analyses of deaths occurring after a minimum period of five years in groups exposed for different durations (5 years, 10 years, 15 years, more than 15 years) indicated no increase in mortality with exposure time. This latter observation also applied to malignant tumors; therefore it may be inferred that prolonged exposure to styrene is not a cancer hazard.