[Mortality analysis in studies of industrial cohorts. III. Testing the trends of standardized relative risks].

The present paper covers the third part of a larger work concerning mortality measures applied in the studies on industrial cohorts. The aim of this paper is to discuss the problems of testing the trends of standardized relative risks (SRR). In spite of its advantages the standardized relative risk (SRR) is not often used in empirical works to assess mortality.

[Effect of the selection of reference population on the evaluation of the degree of the risk of death among industrial cohorts].

The report is devoted to one of the main problems of studies on death rate in industrial cohorts. In the study on cohort consisting of workers of asbestos processing plant in Lodz, the general population of Poland was selected as a reference population. Such method of analysis was used chiefly due to the fact that the data for local population of the Lodz district were unavailable.

[Diagnosis and the reasons for absenteeism among workers with frequent and long-term diseases].

The study was aimed at determination of the realation between sickness absenteeism and medical diagnosis in the groups of employees ailing frequently and for a long time. The analysis covered 5197 randomly selected workers of textile industry in Lodz, From among them a group of 1157 employees ailing for a long time (over 30 days of sickness absenteeism annually) and a group of 888 frequently ill workers (over 3 cases of absence during that period), were selected. In about 63% of the group analysed, the physicians found at least one chronic disease.

[Mortality rates in industrial cohort studies. II. Standardized relative risk].

Presented in the paper are the features of standardized mortality rates (SMR) related to their comparability in different categories of exposure factor as well as features of standardized relative risk (SRR) of the possibility of evaluating the significance of the calculated value of relative risk and possibility of comparing SRR values in different categories of exposure factor. The method of calculating and interpreting SRR was based on the materials of the authors' own cohort study on mortality in a cohort of workers exposed to asbestos dust.

[Epidemiological problems of non-occupational exposure to asbestos dust].

We have presently a sufficient amount of evidence based on epidemiological and experimental investigations to regard asbestos as a carcinogen in human environment. The use of asbestos-containing products and asbestos pollution of the natural environment of man are the risk factors for neoplasms in the general population. The sources of pollution and the values of asbestos dust concentration in community environment and the estimation of the risk related to asbestos dust are presented in the light of epidemiological and ecological studies.

[Problem of cigarette smoking in the epidemiological studies of lung cancer risks among industrial populations].

The concept of the confounding factor is discussed in relation to epidemiological studies, in particular, cigarette smoking is presented as a possible confounding factor in the determination of lung cancer risk in the populations with occupational exposure to carcinogens in their everyday work. In the light of the results of own investigations of a cohort exposed to asbestos dust the confounding effect of smoking on risk of lung cancer risk in this cohort is evaluated.

[Morbidity among textile industry workers evaluated on the basis of cross sectional studies and absenteeism data].

In the study of a randomly selected group of textile workers, a tentative comparative analysis of chronic diseases prevalence rates, as estimated from medical examinations and certificates on temporary work disablement, was carried out. The information from both those sources is highly differentiated, depending on the type of disease. In case of diseases of endocrine glands, metabolism, blood and haematopoietic organs, as well as mental disorders, diseases of the circulatory and osteomuscular systems, the rates of diagnoses through medical examinations considerably surpass those indicated by certificates of temporary work disablement.

[Causes and rates of absenteeism in selected branches of industry during the years 1970-1987].

Since 1970 the Institute of Occupational Medicine in Lódź has systematically carried out the analysis of sickness absenteeism of workers taken care of by the industrial health service. Monthly reports concerning temporal working disability prepared for plants by the institutions of industrial health service constitute the source material for the analysis. The analysis of the rate and structure of sickness absenteeism for the whole industry and its particular branches made it possible to point to industries which are most hazardous to health.

[Mortality ratio in industrial cohort studies].

Presented in the paper is a method of calculating and evaluating the statistical significance of one of the primary measures of mortality in industrial cohort studies--i.e. standardized mortality rate.

[Risk of cancer in women occupationally exposed to asbestos dust].

In order to estimate the risk of death due to cancer in those occupationally exposed to asbestos dust, 1190 women--workers of an asbestos producing plant--employed for at least 3 months during 1945-1973, were examined. The cohort availability for 31 December 1981 was 89.6%.

[Neoplasm risk in men occupationally exposed to asbestos dust].

To evaluate the magnitude of cancer risk in those occupationally exposed to asbestos dust, a historically prospective cohort has been investigated. The observation covered 2403 men employed for at least 3 months, within 1945-1973, in a factory producing various asbestos products--including chrysotile. The cohort availability on 31 Dec.

[Epidemiology of occupational cancer of the upper respiratory tract in Poland 1971-1985].

Incidence of the occupational cancer of the upper respiratory tract has been assessed on the basis of analysis of the data from central register of the occupational disease recognized by the state sanitary-epidemiological service. 99 cases versus 374 all registered occupational cancers of different target organs were found, entirely in men of the mean age 53.6 +/- 6.

[Problems related to studies on the mortality of industrial workers exemplified by observations of persons exposed to asbestos dust].

The most significant problems strictly connected with studies of mortality in industrial cohorts are: selection of reference population, obtention of data for cohorts in historically prospective studies (completeners and reliability of sources of information on employment and death), determination of exposure in retrospective cohorts, disturbing factors, methods of statistical analyses. Basing on literature and their own experience the authoresses thoroughly analysed the first three methodological issues related to studies of mortality rates in industrial cohorts.

[The risk of death from malignant tumors is dependent on the amount of exposure to asbestos dust].

The investigation was carried out in an asbestos plant producing yarn, cords, gaskets and frictional products. Only chrysotile asbestos was used in the production process. The follow-up covered a cohort composed of 2403 men and 1190 women employed in the plant of various asbestos products for at least 3 months during 1945-1973.

[Smoking and cancer risk in persons occupationally exposed to asbestos dust].

Analysed in the paper (basing on literature) is the cancer risk depending on smoking by those exposed to asbestos dust. In addition, results of empirical studies confirming the multiplicative or additive model of the interaction smoking-asbestos and cancer risk were discussed. Some preventive measures for this interaction were indicated, too.

[Occupational hazards of chemical carcinogens].

The paper presents current problems resulting from evaluation of occupational risk of chemical carcinogens in national economy. In addition, conditions and activities facilitating actual evaluation of exposure, i.e.

[Changes in the incidence and structure of absenteeism due to illness in Poland 1970-1982].

The dynamics of absenteeism due to particular causes of diseases of national economy workers in Poland, during 1970-1982, was analysed. An increase of the sickness absenteeism rate by approx. 48%, the annual increase rate coming to about 3%, was noted.