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.

Occupational lung cancer risk for men in Germany: results from a pooled case-control study

Occupational exposures such as crystalline silica, diesel engine exhaust, polycyclic aromatic hydrocarbons, and man-made mineral fibers are strongly suspected to increase lung cancer risk. Two case-control studies in Germany conducted between 1988 and 1996 were pooled for a joint analysis. A total of 3,498 male cases and 3,541 male population controls, frequency matched for age and region, were included in the study. The lifelong history of all jobs and industries was coded and occupational exposures were evaluated by expert rating. Odds ratios, crude and adjusted for smoking and asbestos exposure, were calculated by conditional logistic regression. Job-related evaluation showed a statistically significant increased odds ratio adjusted for smoking among farmers; forestry workers, fishermen, and livestock workers; miners and quarrymen; chemical processors; cabinet makers and related wood workers; metal producers and processors; bricklayers and carpenters; road construction workers, pipelayers and well diggers; plasterers, insulators, and upholsterers; painters and lacquerers; stationary engine and heavy equipment operators; transport workers and freight handlers; and service workers. With regard to specific occupational exposures, elevated odds ratios (OR) (95% confidence intervals (CI)) for lung cancer risk adjusted for smoking and asbestos exposure were observed for man-made mineral fibers (OR = 1.48, 95% CI 1.17, 1.88); crystalline silica (OR = 1.41, 95% CI 1.22, 1.62); diesel engine exhaust (OR = 1.43, 95% CI 1.23, 1.67); and polycyclic aromatic hydrocarbons (OR = 1.53, 95% CI 1.14, 2.04). The risk of asbestos exposure, adjusted for smoking was also increased (OR = 1.41, 95% CI 1.24, 1.60).

Environmental tobacco smoke and lung cancer: a case-control study in Germany

To assess the association between exposure to environmental tobacco smoke (ETS) and lung cancer, the authors personally interviewed 292 lifelong nonsmoking lung cancer cases (recruited from 15 hospitals in the study area) and 1,338 nonsmoking controls (randomly selected by population registries) between 1990 and 1996 in Germany. Subjects were asked by a standardized questionnaire about exposure to ETS in childhood, by spouse, at work, and in transportation and social settings. Several indicators of these different sources of exposure were investigated, using not or low exposed subjects as the reference category. The most informative quantification index was weighted duration of exposure (hours x level of smokiness). No effect of ETS exposure during childhood and no clear effect of spousal ETS were observed. However, for the highest category of exposure, clear effects of ETS at the workplace (odds ratio (OR) = 1.93; 95% confidence interval (CI): 1.04, 3.58), in vehicles (OR = 2.64; 95% CI: 1.30, 5.36), and from all sources combined (OR = 1.39; 95% CI: 0.96, 2.01) were found. Adjustment for occupational carcinogens, radon, and diet did not appreciably change the results. These findings suggest that exposures to high levels of ETS at the workplace and in other public indoor settings appear to be important risk factors for lung cancer risk in nonsmokers.

Gender differences in lung cancer risk by smoking: a multicentre case-control study in Germany and Italy

Several studies in the past have shown appreciably higher lung cancer risk estimates associated with smoking exposure among men than among women, while more recent studies in the USA report just the opposite. To evaluate this topic in a European population we conducted a case-control study of lung cancer in three German and three Italian centres. Personal interviews and standardized questionnaires were used to obtain detailed life-long smoking and occupational histories from 3723 male and 900 female cases and 4075 male and 1094 female controls. Lung cancer risk comparing ever-smokers with never-smokers was higher among men (odds ratios (OR) adjusted for age and centre = 16.1, 95% confidence interval (CI) 12.8-20.3) than among women (OR = 4.2, CI 3.5-5.1). Because the smoking habits of women were different from men, we conducted more detailed analyses using comparable levels of smoking exposure. After restriction to smokers and adjustment for other smoking variables, risk estimates did not differ appreciably between genders. The analysis of duration of smoking (0-19, 20-39, 40+ years) adjusted for cigarette consumption and time since quitting smoking revealed similar risk estimates in men (OR = 1.0, 3.3 [CI 2.6-4.2], 4.1 [CI 3.1-5.6]) and women (OR = 1.0, 2.7 [CI 1.7-4.1], 3.3 [CI 1.9-5.8]). The same was true of the analysis of average or cumulative smoking consumption, and also of analyses stratified by different histological types. We conclude that for comparable exposure to tobacco smoke, the risk of lung cancer is comparable in women and men.

Occupational risk factors for lung cancer among young men

OBJECTIVES

This study evaluated whether occupational exposure plays a role for lung cancer at a very young age.

METHODS

In a pooled analysis of 2 German case-referent studies including 3498 incident cases among men and 3541 male population referents, a group of men (187 cases and 202 referents) aged > or =45 years was compared with a group of 2186 cases and 2146 referents aged 55-69 years. Occupational exposure to known (A list) or suspected (B list) lung carcinogens was assessed using job and industry codes, and exposure to asbestos was assessed using job-specific supplementary questionnaires. A conditional logistic regression was used to calculate the odds ratios (OR) and to control for smoking.

RESULTS

Asbestos exposure showed an odds ratio (OR) of 2.39 [95% confidence interval (95% CI) 1.41-4.04] for the younger group and 1.46 (95% CI 1.24-1.72) for the older group. Having ever worked in a job belonging to the A list as compared with never working in an A- or B-list job was associated with a significantly increased risk for the younger (OR 2.06, 95% CI 1.03-4.12) and older (OR 1.35, 95% CI 1.10-1.65) groups, adjusted for asbestos. Lung cancer risk for those working in A-list jobs at a very young age (under 16 years) was increased in the younger group (OR 6.14, 95% CI 1.41-28.01) in contrast to the older group (OR 1.19, 95% CI 0.91-1.63).

CONCLUSION

Occupational risk factors play an important role for lung cancer among young men. Early age at first exposure may favor an early age of the onset of lung cancer.

Lung cancer risk in male workers occupationally exposed to diesel motor emissions in Germany

BACKGROUND

Although in several epidemiological studies exposure to diesel motor emissions (DME) shows an elevated lung cancer risk, it is still controversial whether DME is a human carcinogen.

METHODS

In a pooled analysis of two case-control studies on lung cancer in Germany a total of 3498 male cases with histologically or cytologically ascertained lung cancer and 3541 male population controls were included. Information about lifelong occupational and smoking history was obtained by questionnaire. Drivers of lorries, buses, taxies, diesel locomotives and forklift trucks, bulldozers, graders, excavators, and tractors, were considered as exposed to DME and their cumulative exposure was estimated. All odds ratios were adjusted for smoking and asbestos exposure.

RESULTS

The evaluation of lung cancer risk for all jobs with DME-exposure combined showed an odds ratio of OR=1.43 (95%-CI: 1.23-1.67). Most pronounced was the increase in lung cancer risk in heavy equipment operators (OR=2. 31 95%-CI: 1.44-3.70). The risk of tractor drivers increased with length of employment and reached statistical significance for exposures longer than 30 years (OR=6.81, 95%-CI: 1.17-39.51). The group of professional drivers (e.g., trucks, buses, and taxies), showed an increased risk only in West Germany (OR=1.44, 95%-CI: 1. 18-1.76), but not in East Germany (OR=0.83, 95%-CI: 0.60-1.14). DME-exposure in other traffic related jobs (e.g., diesel engine locomotive drivers, switchmen, forklift operators) was associated with an odds ratio of OR=1.53 (95%-CI: 1.04-2.24).

CONCLUSIONS

The study provides further evidence that occupational exposure to diesel motor emissions is associated with an increased lung cancer risk.

Worldwide ethnic distribution of the G protein beta3 subunit 825T allele and its association with obesity in Caucasian, Chinese, and Black African individuals

Recently, it was demonstrated that one allele (825T) of the gene encoding the G protein beta3 subunit (GNB3) is associated with hypertension in Germans. This study investigates a possible association with obesity in young male Germans, Chinese, and black South Africans with low, intermediate, and high 825T allele frequencies, respectively. In each of these three distinct cohorts, the 825T allele frequency was increased significantly in overweight (body mass index [BMI] > or =25 kg/m2) and obese individuals (BMI >27 kg/m2) compared to those with normal weight. The 825T allele frequencies in these three BMI groups were, respectively, 29.5, 39.3, and 47.7% in Germans, 46.8, 53.9, and 58.6% in Chinese, and 83.1, 87.7, and 90.9% in South Africans. In each of these three distinct groups, the 825T allele was significantly associated with obesity with odds ratios between 2 and 3. More urban than rural black Africans were overweight despite similar 825T allele frequencies in both populations, which underscores the role of both genetic and environmental factors. BP values in young male whites increased significantly with increasing BMI values but were independent of the C825T polymorphism, suggesting that hypertension associated with the 825T allele could be a consequence of obesity. Genotyping of 5254 individuals from 55 native population samples from Africa, the Americas, Europe, Asia, Australia, and New Guinea demonstrated highest 825T allele frequencies in black Africans (82%) and intermediate values in east Asians (47%). It is anticipated that high frequencies of the 825T allele in Africans and Asians may contribute to an obesity and hypertension epidemic if Westernization of lifestyles continues.

Occupational risk factors for lung cancer in women: results of a case-control study in Germany

BACKGROUND

To investigate the association between lung cancer and occupational factors in women.

METHODS

Six hundred eighty-six women with lung cancer and 712 controls matched for age and region were interviewed to gather occupational histories and information about other risk factors and confounders. Odds ratios (OR) and 95%-confidence intervals (CI) were calculated.

RESULTS

There were 11 cases and 2 controls who reported occupational asbestos exposure. Significantly elevated risks (P < 0.05, smoking-adjusted), were observed in the following industries: chemical, oil (OR 3.7), pottery, glass (OR 2.5), engine, vehicle building (OR 2.2), paper, wood, print (OR 1.9), cleaning service, hairdressing, housekeeping, waste disposal (OR 1.5); and occupations: assemblers, unskilled metal workers (OR 2.5), stock clerks, etc. (OR 1.6), restaurant owners and hoteliers (OR 2.7), as well as waitresses and travel attendants (OR 2.6).

CONCLUSIONS

The study provides evidence that both occupations previously observed as hazardous in males, and occupations of particular significance for women only, play a role in the risk of lung cancer in women.

Descriptive epidemiology of small intestinal malignancies: the German Cancer Registry experience

In the first population-based analysis of certain epidemiologic features of primary malignancies of the small intestine in Germany, we used data from the Saarland Cancer Registry (1982-1993) and from the former National Cancer Registry of the German Democratic Republic (1976-1989). The age-standardized incidence rates for ages 0-74 years is 3.3-6.2 per million per year. The average incidence rates of the federal state Saarland are for men about 1.3 times and for women about 1.4 times the rate of the former German Democratic Republic. After the age of 30 years, the incidence rates increased with increasing age. Incidence rates for carcinoids levelled off after the age of 54 years. Rates for men were 35-40% higher than for women after adjusting for age. The risk for carcinomas, malignant carcinoids and malignant lymphoma were higher for men than for women.

Smoking as a confounder in case-control studies of occupational bladder cancer in women

BACKGROUND

In studies in men, risk estimates on occupation and bladder cancer are distorted by about 10% when not adjusting for smoking. We examined the degree to which occupational risk estimates for bladder cancer in women are confounded by smoking, and the degree of residual confounding by inadequate control of this effect.

METHODS

Primary data of 11 case-control studies on occupation and bladder cancer from Denmark, France, Germany, Greece, Italy, and Spain were pooled. Information for smoking and lifetime occupational history for 700 female cases and 2,425 female controls ages 30-79 was abstracted and recoded. Logistic regression was used to calculate odds ratios (OR) by occupation, applying five models which differed in their degree of adjustment for smoking.

RESULTS

In major occupational groups, risk estimates were distorted by less than 10% when not adjusting for smoking. A statistically significant excess risk for bladder cancer was found in 13 specific occupations and industries. In most occupations, adjustment for smoking led the ORs towards the null value, but all statistically significant associations were maintained after adjustment. In three occupations (lathe operators, field crop workers, and wood manufacturers), a statistically significant excess risk was masked when not adjusting for smoking. In six occupations, estimates were distorted by more than 10% (-22% up to +40%). In occupations where smoking acted as a positive confounder, the proportion of confounding removed using a dichotomous smoking variable (ever/never) was around 60%. In one occupation (buyers), controlling for smoking status (ever, never) led to over-adjustment, because the percentage of smokers was high but the quantity smoked was low.

Occupation and bladder cancer in European women

OBJECTIVES

We examined the importance of occupational exposures for bladder cancer in women.

METHODS

We combined data from 11 case-control studies conducted between 1976 and 1996 in six European countries. The pooled data comprised 700 incident female cases and 2425 population or hospital controls, aged 30-79 years. Lifetime occupational and smoking history were examined using common coding.

RESULTS

Excess risks were found in only a few of the occupations previously identified at high risk for bladder cancer. Statistically significant excess risks were observed for metal workers, particularly blacksmiths, toolmakers and machine tool operators (OR: 2.0, 95% CI: 1.1-3.6), tobacco workers (OR: 3.1, 95% CI: 1.1-9.3), field crop and vegetable farm workers (OR: 1.8, 95% CI: 1.0-3.1), tailors and dress makers (OR: 1.4, 95% CI: 1.0-2.1), saleswomen (OR: 2.6, 95% CI: 1.0-6.9), and mail sorting clerks (OR: 4.4, 95% CI: 1.0-19.5). About 8% (95% CI: 3.1 19.9) of all bladder cancers in women could be attributed to occupation after adjusting for smoking. The attributable risk was higher in women aged less than 65 years (12%), compared to older women (4%).

CONCLUSIONS

The calculation of the attributable risk on the basis of results from this analysis may have caused some overestimation of the proportion of occupational bladder cancer in women. A significant proportion, however, of bladder cancer cases among European women less than 65 years is likely to be attributed to occupation. This link between bladder cancer in women and occupational factors has received little recognition, probably because studies addressing these issues have predominantly been done in men.

Dose-response relationship between amphibole fiber lung burden and mesothelioma

In a mesothelioma case-control study, asbestos and other mineral fibers from lung burden were examined as causal factors. Diagnosis was confirmed by a panel of pathologists. For 66 cases and 66 controls from hospitals in five German towns, lung tissue fiber analysis by transmission electron microscopy was available. Control patients were treated by a surgical lung resection mostly because of lung cancer. For chrysotile and other mineral fibers a significantly increased odds ratio (OR) was not observed. A clear dose-response relationship was demonstrated for the concentration CA of amphibole fibers longer than 5 microm. Between 0.025 and 2.5 fibers/microg dry weight (f/microg) the relationship can be approximated as OR = CA/(0. 025 f/microg). Similar but less distinct dose-response relationships were found in a Canadian and an Australian study. It is concluded that among German mesothelioma patients factors not associated with amphibole fiber concentration are not predominating.

Non-occupational risk factors for cancer of the lower urinary tract in Germany

In a hospital-based case-control study conducted between 1989 and 1992 in Hessen (West Germany) 300 cases (239 male and 61 female) of histologically confirmed cancer of the lower urinary tract (LUT) were individually matched to controls from the same hospitals with respect to sex, age and area of residence. Smoking of cigarettes was associated with an elevated risk of 2.80 in males (95% confidence interval (CI): 1.65-4.76) and 5.33 (95% CI: 1.55-18.33) in females, as compared with nonsmokers. Variables like daily amount of smoked cigarettes, duration of smoking, age at beginning of cigarette smoking and time since smoking cessation showed a clear dose- and time-response relationship in males, but not in females. Elevated risks were observed for higher consumption of coffee, beer and wine, but - especially for the consumption of coffee were drastically reduced after adjustment for smoking. A weak association was found between the daily fluid intake and bladder cancer in males. Among females a significantly decreased odds ratio (OR) of 0.34 (95% CI: 0.11-0.99) was found for a daily fluid intake of more than two liters. Protective effects and risk reductions of approximately 50% were found for the regular intake of raw carrots, kale, salads and fruits. The findings of this investigation support an association between lifestyle factors and cancer of the lower urinary tract.

Effect of age on excess mortality in obesity

CONTEXT

The effect of age on excess mortality from all causes associated with obesity is controversial. Few studies have investigated the association between body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters), age, and mortality, with sufficient numbers of subjects at all levels of obesity.

OBJECTIVE

To assess the effect of age on the excess mortality associated with all degrees of obesity.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

A total of 6193 obese patients with mean (SD) BMI of 36.6 (6.1) kg/m2 and mean (SD) age of 40.4 (12.9) years who had been referred to the obesity clinic of Heinrich-Heine University, Düsseldorf, Germany, between 1961 and 1994. Median follow-up time was 14.8 years.

MAIN OUTCOME MEASURE

All-cause mortality through 1994 among 6053 patients for whom follow-up data were available (1028 deaths) analyzed as standardized mortality ratios (SMRs) using the male-female population of the geographic region (North Rhine Westphalia) as reference.

RESULTS

The cohort was grouped into approximate quartiles according to age (18-29, 30-39, 40-49, and 50-74 years) and BMI (25 to <32, 32 to <36, 36 to <40, and > or =40 kg/m2) at baseline. The SMRs showed a significant excess mortality with an SMR for men of 1.67 (95% confidence interval, 1.51-1.85; P<.001) and an SMR for women of 1.45 (95% confidence interval, 1.34-1.57; P<.001). The excess mortality associated with obesity declined with age. For men, the SMRs of the 4 age groups were 2.46, 2.30, 1.99, and 1.31, respectively; for women, they were 1.81, 2.10, 1.70, and 1.26, respectively (Poisson trend test, P<.001). The SMRs increased with BMI but, within each BMI group, the SMRs decreased with age. The lowest SMRs (for men, 1.01; for women, 0.91) were obtained for patients older than 50 years with BMIs of 25 to less than 32 kg/m2. Thus, older men and women at a BMI range of 25 to less than 32 kg/m2 had no excess mortality. The highest SMRs (for men, 4.22; for women, 3.79) were calculated for the patients aged 18 to 29 years with a BMI of 40 kg/m2 or higher.

CONCLUSIONS

In this large cohort of obese persons, risk of death increased with body weight, but obesity-related excess mortality declined with age at all levels of obesity.

Cigar and pipe smoking and lung cancer risk: a multicenter study from Europe

BACKGROUND

Because limited information is available on the quantitative association between consumption of tobacco products other than cigarettes and lung cancer risk, we undertook a case-control study of this relationship.

METHODS

We investigated lung cancer risk among smokers of cigars and/or cigarillos only and of pipes only and compared these risks with the risk of smokers of cigarettes only in a case-control study conducted in seven European areas. Our study population consisted of 5621 male case patients with lung cancer and 7255 male control subjects. Each subject or his proxy was interviewed with respect to the subject's smoking history and other risk factors for lung cancer.

RESULTS

The odds ratio (OR) for smoking cigars and cigarillos only was 9.0 (95% confidence interval [CI] = 5.8-14.1), based on 43 exposed case patients and 77 exposed control subjects, and the OR for smoking a pipe only was 7.9 (95% CI = 5.3-11.8), representing 61 case patients and 129 control subjects. The OR for smoking cigarettes only was 14.9 (95% CI = 12.3-18.1), based on 4204 case patients and 3930 control subjects. A dose-response relationship was present for duration of use and cumulative consumption both for cigars and cigarillos and for pipe tobacco. An effect was also suggested for inhalation of cigar and cigarillo smoke. The dose-response relationships between lung cancer risk and either duration of smoking or average and cumulative consumption were similar for cigar and cigarillo smoking, pipe smoking, and cigarette smoking.

CONCLUSION

Our results suggest that smoking of European cigars, cigarillos, and pipe tobacco might exert a carcinogenic effect on the lung comparable to that of cigarettes.

Perspectives of clinical epidemiology in Germany

The aim of this article is to discuss the perspective of clinical epidemiology in Germany. The following statements are discussed: (1) There is some confusion about the definition of clinical epidemiology. (2) There is a latent and growing need for clinical epidemiology in Germany. (3) Clinical epidemiology is an interdisciplinary field and not simply clinical medicine, epidemiology, biometry, or medical informatics. (4) We must continue with the education of clinicians and nonclinical methodologists in clinical epidemiology to develop the field of clinical epidemiology in Germany, Biometry, medical informatics, and epidemiology will play an essential role for this purpose. (5) The German scientific community urgently needs clinicians and scientists with experience in methodological research to specialize in the methods of clinical epidemiology. (6) The starting point for the development of clinical epidemiology in Germany, clear deficits in the past notwithstanding, is promising. However, we will only be able to develop the field if the egoism of the different disciplines can be tamed.

Control response proportions in population-based case-control studies in Germany

We investigated the methods of recruitment, levels and determinants of response, and the calculation method of response proportions in population-based case-control studies in Germany. We identified 26 eligible studies. The pooled analysis showed that the response proportion was 68% among controls and 80% among cases. Response proportions among controls without telephones were about 50% lower than for controls with telephones. We propose a new measure that indicates the efficacy of the recruitment strategy.

[Linking survey data with routine health and accident insurance data]

Data of the social security institutions, although gathered for administrative purposes, provide important information on work-related morbidity. The validity of the data can be improved by linking several data sources and data from questionnaires or medical examinations. Hence, within the framework of the "Cooperative Programme Occupation and Health" (KOPAG) a specific procedure for data linkage was developed. Data linkage was effected via an anonymous social security number on the one hand, and on the other hand a constructed short number using informations on birthday, sex, and the first letter of the surname of the employees. By means of this short number an average 62% of the questionnaires could be linked to the health insurance sickness leave data. Data linkage was particularly successful (85%) under specific advantageous conditions. Data linkage failed in 25% of all cases because the information necessary to construct the short number was obviously wrong. In general, this procedure to link survey data to routine data of the social security proves suitable for use in routine health reporting.

[Early recognition of prostate carcinoma. Initial results of a prospective multicenter study in Germany. Project Group for Early Detection DGU-BDU Laboratory diagnosis Professional Circle]

To compare the efficacy of digital rectal examination (DRE) and serum prostate specific antigen (PSA) in early detection of prostate cancer, we initiated a prospective multicenter screening trial. In 12,542 men choosen at random with a mean age of 62 (+/- 7.5) a suspect DRE or a PSA level > 4.0 ng/ml was found in 2343 (20%). Of the presently performed 744 biopsies, 157 revealed diagnosis of prostate cancer. Although further biopsies as well as the follow up of the 12,542 men are still missing, combination of DRE and PSA value > 4.0 ng/ml appears to be superior to DRE alone with a positive predictive value of 50% versus 19% in early detection of prostate cancer.

Tobacco, occupation and non-transitional-cell carcinoma of the bladder: an international case-control study

Transitional-cell carcinoma is the dominant histological type of malignant tumors of the urinary bladder. There is limited information on risk factors for non-transitional-cell carcinoma (NTCC) of the bladder. We used data from 9 case-control studies on bladder cancer from 6 European countries to examine the association between NTCC, tobacco smoking and occupation. Information on 146 cases diagnosed with NTCC were matched by age, gender and study center to 727 non-cancer population or hospital controls and also with 722 transitional-cell-bladder-cancer controls. Lifetime smoking and occupational history were evaluated. A statistically significant excess risk for NTCC was observed for current smoking [odds ratio (OR) = 3.61, 95% confidence interval (CI) 2.08-6.28]. The risk increased with higher tobacco consumption (OR for highest tertile of pack-years = 7.01, 95% CI 3.60-13.66). The risks were higher for squamous-cell carcinomas than for other types of NTCC. Among major occupational groups, a significant excess risk was seen for field-crop and vegetable-farm workers (OR = 2.06, 95% CI 1.03-4.10). These results indicate that NTCC of the bladder is associated with smoking and specific occupations. The risk pattern seems to differ, in part, from that observed for transitional-cell carcinoma of the bladder.

Environmental tobacco smoke and lung cancer

In a case-control study of 1,004 lung cancer cases and 1,004 population controls, all nonsmokers (71 cases, 236 controls) were interviewed for their exposure to environmental tobacco smoke. On the basis of indices of duration, we separated intermediate and high exposures from low or no exposure. The odds ratio for high exposure was 2.09 (95% confidence interval = 1.02-4.28). Exposure from the spouse was only weakly associated with lung cancer risk. We found little association for exposure during childhood. High exposure at the work place showed an odds ratio of 1.91. There was little indication of confounding by dietary habits.

Multicenter case-control study of exposure to environmental tobacco smoke and lung cancer in Europe

BACKGROUND

An association between exposure to environmental tobacco smoke (ETS) and lung cancer risk has been suggested. To evaluate this possible association better, researchers need more precise estimates of risk, the relative contribution of different sources of ETS, and the effect of ETS exposure on different histologic types of lung cancer. To address these issues, we have conducted a case-control study of lung cancer and exposure to ETS in 12 centers from seven European countries.

METHODS

A total of 650 patients with lung cancer and 1542 control subjects up to 74 years of age were interviewed about exposure to ETS. Neither case subjects nor control subjects had smoked more than 400 cigarettes in their lifetime.

RESULTS

ETS exposure during childhood was not associated with an increased risk of lung cancer (odds ratio [OR] for ever exposure = 0.78; 95% confidence interval [CI] = 0.64-0.96). The OR for ever exposure to spousal ETS was 1.16 (95% CI = 0.93-1.44). No clear dose-response relationship could be demonstrated for cumulative spousal ETS exposure. The OR for ever exposure to workplace ETS was 1.17 (95% CI = 0.94-1.45), with possible evidence of increasing risk for increasing duration of exposure. No increase in risk was detected in subjects whose exposure to spousal or workplace ETS ended more than 15 years earlier. Ever exposure to ETS from other sources was not associated with lung cancer risk. Risks from combined exposure to spousal and workplace ETS were higher for squamous cell carcinoma and small-cell carcinoma than for adenocarcinoma, but the differences were not statistically significant.

CONCLUSIONS

Our results indicate no association between childhood exposure to ETS and lung cancer risk. We did find weak evidence of a dose-response relationship between risk of lung cancer and exposure to spousal and workplace ETS. There was no detectable risk after cessation of exposure.

Occupational risk factors for lung cancer: a case-control study in West Germany

BACKGROUND

The aim of this study is to evaluate carcinogens and occupations suspected to cause lung cancer and to generate new hypotheses about occupational risks.

METHODS

In a hospital-based study 1004 incident lung cancer cases and the same number of population controls matched for region, sex and age were interviewed between 1988 and 1993 for their smoking and occupational history. Exposure assessment was based on 33 job-specific supplementary questionnaires. Conditional logistic regression was used to calculate odds ratios (OR) and to control for smoking and occupational asbestos exposure.

RESULTS

Lifelong prevalence of exposure to asbestos was 20.5% for exposure of more than 940 lifetime working hours among controls, corresponding to an OR of 1.62 (95% confidence interval [CI] : 1.28-2.05) that was reduced to 1.45 after adjustment for smoking (P < 5%). Statistically elevated risks after adjustment for smoking and asbestos were seen in metal production and processing workers, transportation workers and freight handlers, in the rubber and plastics industry, in metal production, in engine and vehicle building, and installation. Significantly increased OR after adjustment for smoking and asbestos that deserve further attention were seen in plastics processing workers (OR = 3.49), and sheet and structural metal workers (OR = 2.01 and 2.37, respectively).

CONCLUSIONS

The results of the study confirm previously described occupational risks. Because of the possibility of controlling for occupational asbestos exposure, the study gives clear indications for prevention and further research.

Lung cancer risk and welding: results from a case-control study in Germany

In a case-control study, 839 male hospital-based cases of primary lung cancer and the same number of population-based controls--matched by sex, age, and region of residence--were personally interviewed for their job and smoking histories. The study allows to quantify occupational asbestos exposure that was thought to be a welding-associated risk: 6% of cases and 2% of controls were classified into the occupational category "welders or burners# (odds ratio [OR] = 2.65). This OR was reduced to 1.93 (95% confidence limit [CL]: 1.03-3.61) after adjustment for smoking and asbestos. In contrast, a history of welding in general for at least a half-year is 28% among cases and 23% among controls, yielding an OR of 1.25 (95% CL: 0.94-1.65) after adjustment for both confounders. The OR of welding for more than 6,000 hr is 1.45 (95% CL = 1.04-2.02), reduced to 1.10 after adjustment for smoking and asbestos. Oxyacetylene welding for more than 6,000 hr lifelong is associated with an OR of 1.86 (95% CL = 1.01-3.43) reduced to 1.46 (n.s.) after adjustment for smoking and asbestos. The risk of oxyacetylene welding seems to be highest for oat cell carcinoma with an adjusted OR for ever-exposure of 1.46 (95% CL = 0.69-3.10). Therefore, the present study supports the hypothesis that some, but not all, of the excess risk of welders observed in the literature may be due to a history of cigarette smoking and occupational asbestos exposure. The elevated risk for the subgroup of employees in the aircraft industry reported for the midterm evaluation of the study still prevails, though no longer statistically significant. However, employees in this industry who ever welded show an OR of 2.29 (95% CL = 1.19-4.42) after adjustment for smoking and asbestos.

The relation between various histological types of lung cancer and the number of years since cessation of smoking

We studied the relation between various histological types of lung cancer and the number of years of cessation from smoking using data from a recently completed case-control study in Northern Germany. In this context we wanted to answer the question whether smoking cessation is a specific symptom of small cell lung cancer. Defining current smokers as the reference group the odds ratios decreased with years of cessation. Based on the analysis of all male cases and controls in our study, former smokers who stopped smoking 6-10 years ago had an odds ratio of 0.97 (95% confidence interval (C.I.) = 0.65-1.45), ex-smokers with 11-20 years of smoking cessation had a reduced risk of 0.55 (95% C.I. = 0.38-0.79), and for more than 20 years of cessation we found an odds ratio of 0.25 (95% C.I. = 0.16-0.40). Moreover, these calculations are also presented for the major groups of histological types of lung cancer. Our data show that there is no evidence for the presumption that cases with small cell lung cancer stop smoking earlier than cases with other histological types: in no other histological category we found such a big part of current smokers.

[Occupationally-induced lung cancer--a quantitative evaluation for the North Germany area]

The aim of the study was to estimate the proportion of occupation-related lung cancer for males and females in Northern Germany. 1004 lung cancer cases (839 males, 165 females) were enrolled into an epidemiological case-control study in the study areas Bremen, the surroundings of Bremen and the Frankfurt/Main area. Population controls were matched for sex and region of residence. All patients born after 1913 of German nationality and with a histologically or cytologically verified carcinoma of the lung, the diagnosis not older than 3 months at the date of interview, were eligible. All individuals were personally interviewed with respect to their smoking and job history. Based on a published list of all jobs and branches of industries with sufficient evidence for lung carcinogenity (based on the reviews by IARC), the so called A-List, all individuals were classified regarding their lifelong occupational history. The same procedure was applied with regard to jobs and branches of industries with a suspected risk of lung cancer (List-B). The statistical analysis used conditional logistic regression, controlled for smoking. Being employed in a job of List-A for at least half a year was associated with a statistically significant odds ratio (OR) of 1.63 (p < 0.0001) and resulting attributable risk (AR) of 16% in males. For the B-List an OR of 1.34 and an AR of 10% resulted in males. The estimates of the attributable risk for jobs and branches of industry with a sufficient evidence of lung cancer risk is comparable to the estimates obtained by Doll and Peto for the US. If additionally jobs and branches of industries with a suspected risk for lung cancer is considered, it must be anticipated that approximately one quarter of all newly diagnosed male lung cancer cases in the study region may be caused by occupational risk factors. This should prompt to minimise occupational exposure.

Prognostic implications of monosomy 3 in uveal melanoma

BACKGROUND

A high proportion of patients with uveal melanoma die of metastatic disease. In a subgroup of uveal melanomas there is the loss of one chromosome 3. To assess the prognostic implications of this genetic anomaly, we studied 54 patients for a median of 3.4 years.

METHODS

180 patients underwent primary enucleation for malignant uveal melanoma at the Ophthalmology Department of the Universitätsklinikum Essen between 1987 and 1993. Tumour material was available for chromosome analysis and DNA preparation from 69 of these patients (for logistic reasons unlikely, we believe, to introduce bias). 15 patients were excluded from our study: nine because the methods for assessment of monosomy 3 were unsuccessful; five because of insufficient information about their relapse status; one because histopathological data were incomplete. Of the 54 remaining patients, the tumours of 16 were assessed for copy number of chromosome 3 by karyotype analysis, of 30 by comparative genomic hybridisation, and of eight by both techniques. Clinical status was assessed by contact with family doctor or a clinical check up. Statistical analysis was by the log-rank test and Cox proportional-hazard regression.

FINDINGS

The tumours of 30 patients had monosomy 3. 17 (57%) of these patients relapsed with metastatic disease, and the 3-year relapse-free survival rate was 50%. By contrast, of the 24 patients whose tumours had retained both chromosomes 3, none developed metastatic disease. In univariate analysis monosomy 3 was the most significant (p < 0.0001) predictor of poor prognosis in uveal melanoma, followed by tumour location (p < 0.0007) and tumour diameter (p < 0.0021). Histopathological subtype, age, sex, extrascleral growth, and tumour thickness had no additional predictive value.

INTERPRETATION

In uveal melanoma, monosomy 3 is a significant predictor of both relapse-free and overall survival.

Spatial-temporal analysis of mortality using splines

A method for constructing contour maps in disease mapping using smoothing splines is presented. Smoothing errors are discussed and error maps suggested. The approach is illustrated for mortality data on cardiovascular diseases in northwestern Germany (Lower Saxony and Bremen) 1970-1979.

Occupational life course and lung cancer risk in men. Findings from a socio-epidemiological analysis of job-changing histories in a case-control study

Psychosocial factors in general, and the social and psychological conditions of work and occupation in particular, have attracted little attention to the epidemiological investigation into the occupational-related causes of lung cancer. There is some evidence available concerning the impact of loss events--including job losses--on cancer development. During our research presented in this article, we examined job changes and job transitions in the occupational biography of men with regard to their circumstances in terms of (in-)voluntariness both as individual events and the job-changing histories of individuals. We expected the job-changing histories of lung cancer cases to be more involuntary than those of population controls, and vice versa. Our sample contains 391 male case-control pairs. Cases are defined as newly-diagnosed men of German nationality with a histologically- or cytologically-confirmed diagnosis of primary lung cancer. Population controls were drawn randomly from the municipality records of residents and individuals matched to cases 1:1 by age and region. Occupational histories were reconstructed, and information about other classical and suspected risk factors was collected during standardized interviews by trained interviewers. We categorized the reported reasons for job changes, and classified them with respect to voluntariness on a seven-stepped rating scale from -3 'very involuntary' to +3 'very voluntary', defining relations within the empirically established categories. The job-changing histories of individuals are described by using the average score of voluntariness. We measured the degree of voluntariness for the occupational history: (1) by the rounded average score; and (2) by the quintiles of the average score. On the basis of individuals matched odds ratios (OR) estimates are derived for the score of voluntariness unadjusted and adjusted for smoking, asbestos exposure and socio-economic group by conditional logistic regression. The investigation into job-changing histories using the average score of voluntariness lead to similar results for both measuring methods for the total study group. When the rounded score was used, job-changing histories which were assessed as 'very involuntary' and 'involuntary' (score -3 and -2) showed an elevated odds ratio of adjusted 1.41 (95%-CI: 0.57; 3.48), and when they were assessed as 'moderately involuntary' (score -1) the adjusted odds ratio was 1.59 (95%-CI: 1.02; 2.48), as compared with job-changing histories assessed as neutral (score 0). When the degree of voluntariness was measured by quintiles, the first quintile (score -3- < -0.6) showed an elevated risk of adjusted OR 1.36 (95%-CI: 0.79; 2.36) as compared to the third quintile (score -0.2- < -0.1).(ABSTRACT TRUNCATED AT 400 WORDS)

Lung cancer risk and welding--preliminary results from an ongoing case-control study

In a hospital-based case-control study, 391 male cases or primary lung cancer and the same number of controls--matched by sex, age, and region--were personally interviewed for their job and smoking histories. The data reported reflect the midpoint of a study aiming at a total of 1,000 cases. One objective of the study was to assess confounding by asbestos exposure in what was thought to be a welding-associated risk. While the odds ratios (OR) increased steeply with cumulative exposure to tobacco smoke and were raised also for lifelong asbestos exposure of over 4,100 working hours (OR = 1.91), the effect of welding exposure was reduced after adjustment for smoking and exposure to asbestos. Furthermore, no consistent dose-response relationship could be shown in relation to welding hours. Therefore the present study supports the hypothesis that some, if not all, of the excess risk of welders observed in the literature may be due to the exposure to asbestos. The finding that the subgroup of employees in the aircraft industry showed an increased odds ratio of 2.14 after adjustment for smoking and exposure to asbestos deserves further attention. This suggests the need for further research on the role of berryllium-containing alloys, which has been suggested by other authors.

The analysis of case-control studies under validation subsampling

In case-control studies, one often finds that covariates are missing or measured with error in the entire sample, whereas complete or exact covariate information is available only in a subsample. This paper discusses the analysis of case-control studies under a double-sampling scheme, where at the first stage covariates are measured with error or missing, and at the second stage are validated in a subsample. The method proposed combines the risk information from both samples by assuming that (1) the disease incidence model is logistic, (2) the partial or proxy information takes on finitely many values, and (3) the error is non-differential. The estimator is obtained by jointly fitting logistic models to the first and second stage data, a variance formula is presented. Parameters can be estimated by use of standard packages for dose-response data. Data from an ongoing case-control study on lung cancer serve as an example.

Retrospective assessment of asbestos exposure--II. At the job level: complementarity of job-specific questionnaire and job exposure matrices

Retrospective assessment of asbestos exposure--II. At the job level: Complementarity of job-specific questionnaire and job exposure matrices. International Journal of Epidemiology 1993; 22 (Suppl. 2): S96-S105. The assessments of asbestos exposure by two a priori job exposure matrices (JEM) and by a job-specific questionnaire (SQ) are compared at job level. The data used for the comparison were generated by an ongoing case-control study on lung cancer in a region of northern Germany with a relatively high past prevalence of asbestos exposure. Among job periods assessed as unexposed by either JEM, 96% are recognized as such by the SQ. Discrepancies between the SQ and JEM were observed in jobs rated potentially exposed by the JEM. Despite varying estimates, the JEM and SQ were consistent as regards the relative classification of job periods by probability of exposure. The concordance of the methods, estimated by Kappa statistics, was stronger for the two JEM than for either of the JEM and the SQ. The identification of specific occupation/industry combinations in which discrepancies were most frequent and the comparison with expert ratings in some jobs yield insights into the sources of the disagreement between the methods. The misclassification of exposure by the JEM usually results in an overestimation of exposure. This is essentially related to loss of information due to the use of job codes as surrogates for job task descriptions and to the insufficiency of published data on asbestos exposure in different industries. As regards the SQ, two main sources of potential loss of sensitivity were identified: 1) possible omission of indirect sources of exposure by this method, 2) possible incompleteness of the SQ. The present comparison of methods of asbestos exposure assessment does not allow any one approach to be considered superior to another. Indeed, as proposed by Ahrens et al. in Part I of the study, both should be used to ensure optimal epidemiological performance.

Retrospective assessment of asbestos exposure--I. Case-control analysis in a study of lung cancer: efficiency of job-specific questionnaires and job exposure matrices

Retrospective assessment of asbestos exposure--I. Case-control analysis in a study of lung cancer: efficiency of job-specific questionnaires and job exposure matrices. International Journal of Epidemiology 1993; 22 (Suppl. 2): S83-S95. In a lung cancer study in Northern Germany the asbestos exposure assessment obtained from detailed supplementary questionnaires (SQ) was compared to the assessment obtained by the application of two job exposure matrices (JEM) to the job history. The study includes 391 incident male cases and the same number of controls from the general population, matched by sex, age, and region. Almost 16% of the subjects are considered as never having been exposed to asbestos and 24% are classified as certainly exposed according to both of the JEM, the corresponding percentages of the SQ-method being 68% and 32%. Sixty percent are considered by the JEM as having an intermediate probability of exposure. In general, the agreement between the different methods is better when the exposure definition is restricted to definite exposures, the corresponding Kappa statistic being 0.67 for the comparison between both JEM and 0.44/0.39 between the JEM and the SQ. The positive agreement between SQ and JEM (reference) increases from 12% and 17% for subjects with low probability of exposure to 61% and 69% for those with definite exposures. A ranking according to cumulative exposure shows some dose-response relationship for each of the three methods with a smoking-adjusted OR in the highest category of 1.85 (95% CI: 1.01-3.38) for the SQ method and 2.47 (95% CI: 1.40-4.37) and 2.94 (95% CI: 1.73-4.99) for the two JEM. The results are discussed with reference to the conceptual differences between the methods and their potential scope in future studies.

Passive smoking in Germany and Poland: comparison of exposure levels, sources of exposure, validity, and perception

Nonsmoking females age 35-65 years from Bremen, Germany (91 women), and Opole, Poland (98 women), were interviewed about their recent passive smoking exposure. We obtained urine samples at the time of interview and determined the concentration of cotinine as an indicator of tobacco smoke exposure. In Poland and in Germany, the vast majority of nonsmoking women are involuntarily exposed to environmental tobacco smoke (ETS). Polish women had slightly higher exposure levels than German women, with overall means of 9.93 and 8.65 ng cotinine/mg creatinine, respectively. Smoking by the husband was the major source of exposure in both study groups. In the Polish group, the work place was also an important source of ETS exposure. The validity of self-reported passive smoking exposure was found to be generally good; it was somewhat better in the German study group. A negative attitude toward tobacco smoke was slightly stronger among the German women. The percentage of women misreporting their active smoking status was low.

Occupational and environmental hazards associated with lung cancer

In a hospital-based case-control study 194 lung cancer cases, 194 hospital controls, and 194 population controls were interviewed for their smoking, occupational, and residential history by trained interviewers, using a standardized questionnaire. In order to include many different environmental exposures, case ascertainment took place in seven different hospitals with catchment areas ranging from rural to highly industrialized. Lung cancer risk strongly increases with cumulative cigarette dose, reaching an odds ratio (OR) of 16.19 (95% confidence limits (CL): 5.10, 51.33) for male smokers of more than 40 pack-years and an OR of 19.99 (95% CL: 4.98, 80.24) for female smokers of more than 20 pack-years. For the quantification of occupational exposure to known carcinogens of the lung a novel approach was developed which accumulates exposure information obtained by supplemental questionnaires through an automatic procedure. The OR for the highest exposure group in males was 2.7 (95% CL: 1.23, 5.78). Significantly increased risks were observed in the metal industry, particularly in smelter and foundry workers (OR 4.8, 95% CL: 1.15, 20.16) and in turners (OR 2.2, 95% CL: 1.05, 4.75). In the construction industry the risks were particularly high in road construction workers (OR 3.7, 95% CL: 1.06, 13.20) and in unskilled construction workers (OR 2.7, 95% CL: 1.24, 5.76). The risks in these occupational groups increased with duration and with latency. Quantification of air pollution was done on a county basis by time period. An index based on emission data for sulphur dioxide was compared to a semiquantitative index, which included additional information on ambient air pollution. After adjustment for smoking and occupational exposures an OR of 1.01 (95% CL: 0.53, 1.91) for an emission index and of 1.16 (95% CL: 0.64, 2.13) for a semiquantitative index was obtained.

Effects of nondifferential exposure misclassification in ecologic studies

Although many authors have argued against inferring individual-level exposure-disease relations from ecologic data because of the potential "ecological fallacy." the availability of data from diverse populations promotes the continued use of this rapid and inexpensive study design. In ecologic studies, the exposure status of groups is often defined by the proportion of individuals exposed. In these studies, nondifferential exposure misclassification of individuals is shown to produce overestimation of exposure-disease associations that may be extreme when the ecologically derived rate ratios are applied to individuals. This overestimation contrasts with the bias toward the null resulting from nondifferential misclassification of a binary exposure in epidemiologic studies conducted at the individual level. Given the magnitude of the potential bias from nondifferential exposure misclassification and other sources, quantitative estimates of individual-level rate ratios from ecologic data should be interpreted with extreme caution.

Smoking cessation and nonsmoking intervals: effect of different smoking patterns on lung cancer risk

A case-control study of lung cancer was conducted in northwestern Germany in 1985-86. The study included 194 lung cancer cases and the same number of hospital controls and population controls who were matched to the cases by sex and age. Personal interviews were conducted by trained interviewers. We report here the effect of different smoking patterns--such as nonsmoking intervals, and time since quitting smoking--on lung cancer risk. Both quitting smoking and having a nonsmoking interval are seen to reduce lung cancer risk significantly. For a nonsmoking interval of three years or more, relative risk (RR) = 0.21, 95 percent confidence interval (CI) = 0.08-0.52; for quitting smoking for 10 years or more, RR = 0.23, CI = 0.11-0.48). A dose-response relationship was estimated for cigarette dose, length of nonsmoking interval, and time since stopped smoking.

Alcohol, smoking, and occupational factors in cancer of the larynx: a case-control study

A hospital-based case-control study of laryngeal cancer was conducted in Bremen in 1986 and 1987 with 100 prevalent male laryngeal cancer patients and 100 male hospital controls with diseases not considered to be related to smoking, alcohol, or occupational exposures, who were frequency matched by age. The odds ratio for heavy smoking (more than 30 pack-years) reached a value of 3.5 (95% confidence limits (CL) 1.1, 7.9). Ex-smokers showed a significant decrease in risk; this reached the level of those who had never smoked about 15 years after smoking cessation. For daily consumers of alcohol an odds ratio of 3.2 (95% CL 1.4, 7.5) was observed. Among the 17 occupations in which at least ten subjects had worked, excess risks were observed for stock keeping and transportation workers, and for leather and textile workers. The odds ratio was significantly increased for the latter (p less than 0.05). Among all those persons ever employed in a priori defined-risk occupations, an odds ratio of 2.74 (95% CL 1.23, 6.06) was observed. Considering responses to an exposure check-list, no increased risks could be shown for exposure to asbestos, coal tar, or welding fumes. On the other hand, excess risks were observed for exposures to diesel oil, gasoline, and mineral oil, controlling for smoking and alcohol. The findings in occupational and exposure subgroups were based on small numbers of cases and controls and, consequently, were subject to large sampling errors. Many of the results are consistent, however, with occupational risk factors reported from other studies.

[Results of the histology of bronchial carcinoma form an epidemiological study in North Rhine-Westphalia and northern Germany]

In a case-control study to examine the risk factors for bronchial carcinoma, 194 histologically confirmed cases of lung cancer and twice the number of controls (194 hospital controls, 194 population controls) were covered. In addition, the histological material obtained from 139 patients was assessed by a reference pathologist. In 107 cases (77%) the data coincided with the findings by the hospital pathologists. In women, young patients and persons with better general job qualifications adenocarcinomas and other bronchial carcinomas were seen more often and small-cell carcinomas as well as squamous cell carcinomas were rarer. Smoking did not entail any significant difference in respect of bronchial carcinoma risk. There was a significant risk increase among persons occupationally exposed to polycyclic aromatic hydrocarbons, arsenic, chromium, nickel and radionuclides in respect of squamous cell and small-cell carcinomas but not of adenocarcinomas and other histological types of carcinoma.

The design of case-control studies: the effect of confounding on sample size requirements

This paper considers the extent to which confounding effects of covariates, which are not controlled for by matching in the design, may influence the sample size necessary for case-control studies. The quantitative calculations are performed for an age-matched case-control study on lung cancer and air pollution, and are based on different evaluation methods. For illustrative purposes attention is confined to a dichotomous risk factor and a single dichotomous covariate. By using the numerical values of a pilot study investigating lung cancer and air pollution, it turns out that the sample size required for detecting a relative risk as close as 1.15 to 1 is only slightly influenced by the strength of the association between confounder and risk factor for reasonable variations around our empirical values. On the other hand, sample size considerably increases with increasing relative risk of a confounder even when the association remains small. The sample size required for an individually matched analysis practically equals that for an age-stratified analysis when the relative risk of the covariate is one. With a relative risk greater than one, however, the size for a matched analysis exceeds that for a stratified analysis and the ratio between them increases with increasing relative risk.

[Results of the epidemiology of lung cancer in females]

In the context with an extensive pilot study investigating risk factors for lung cancer, aetiological and clinical questions were analysed for lung cancer mortality in women. In a first step all available data sources about the prevalence of smoking in the FRG were used to determine the correlation between the prevalence of smoking and lung cancer mortality. 88% of the variance (R2) of lung cancer mortality for women could be explained by smoking. In a second step medical records of 133 female lung cancer patients from three hospitals were analysed with regard to the histological types of lung cancer and smoking. Small cell lung cancers were more frequent among female smokers while adenocarcinoma was more prevalent among non-smokers. Survival analysis for 421 men and 97 women showed a significantly longer survival time for women as compared to men, taking into account other relevant prognostic factors. The association between smoking and lung cancer is discussed and analysed in greater detail.

Viscoelasticity and red blood cell aggregation in patients with coronary heart disease

Viscoelastic parameters were evaluated in 169 consecutive male patients with clinical signs of coronary heart disease. The patients were classified according to the extent of coronary artery stenosis. Levels of blood viscosity, erythrocyte aggregation, and plasma viscosity were elevated in patients with extensive coronary vessel disease. However, the differences between the several groups were not statistically significant. The increase of hemorheologic parameters was mainly due to high hematocrit, fibrinogen, and cholesterol concentrations. There was a significant correlation between plasma fibrinogen values and plasma viscosity levels. Blood viscosity and erythrocyte aggregation can be described by multiple linear regression as a function of the sum of log hematocrit, fibrinogen, cholesterol, and alpha 2-macroglobulin.

Cardiovascular mortality in the Federal Republic of Germany, 1970-79, and the evaluation of the German Cardiovascular Prevention Study: results from a geographic mortality study

The primary endpoint of the German Cardiovascular Prevention Study (GCP), cardiovascular mortality, has to be based on the official mortality statistics. In the scope of a geographic mortality study trends and regional variations of ischemic heart disease (ICD-9, 410-414) and cerebrovascular disease (ICD-9, 430-438) mortality were investigated. During the study period from 1970 to 1979 a relevant decline of cerebrovascular diseases in men and women was observed, whereas ischemic heart disease mortality figures remained relatively stable. Over time the importance of ischemic heart disease mortality has increased. The geographic analysis points to relevant problems concerning the validity of mortality data due to the particularities of the German mortality statistics (separately signed in the 11 statistical offices of the 11 federal states). The mortality rates of the four intervention regions of the "Kooperative Prävention" (corresponding data of "Kommunale Prävention" not available) indicate that the intervention regions are at a considerably lower level than the FRG, the mortality patterns, however, paralleling those of the FRG. As far as mortality structures are concerned, ischemic heart diseases are more important in the intervention regions than in the FRG as a whole.