Long-term epidemiological observation of asbestos-related diseases in Poland, 1970-2015.

BACKGROUND: Occupational exposure to asbestos constitutes a major public health concern. Despite this in many countries, data and registration systems for occupational asbestos-related diseases are non-existent or poorly developed. AIMS: To analyse the incidence of occupational asbestos-related diseases in Poland between the years 1970 and 2015, with particular emphasis on the periods after introduction of a ban on asbestos and following introduction of a surveillance programme. METHODS: Analysis based on all medically recognized cases, certified as occupational diseases and reported obligatorily from all over the country to the Central Register of Occupational Diseases. RESULTS: During the period 1970-2015, 4983 cases were reported as asbestos-related diseases. The most prevalent were asbestosis, lung cancer, diseases of pleura or pericardium and mesothelioma. A considerable increase in the number of such cases from the beginning of their registration until 2004 occurred after introduction of the Amiantus programme, a nationwide programme of periodic medical examinations for former asbestos workers. CONCLUSIONS: Introduction of a medical surveillance programme improved case recognition and allowed a more reliable estimate of the number of reported asbestos-related diseases.

Indoor air pollution from solid fuels and risk of upper aerodigestive tract cancers in central and eastern Europe.

BACKGROUND: Indoor air pollution from solid fuels is a potentially important risk factor for cancer, yet data on cancers from organs other than the lung are scarce. We investigated if indoor air pollution from coal and wood are risk factors for additional cancers, particularly that of the upper aerodigestive tract (oral cavity, larynx, pharynx and esophagus) in the high-risk areas of central and eastern Europe. METHODS: We used data from multi-center hospital-based case-control study of 1065 histologically confirmed upper aerodigestive tract cancer cases and 1346 controls. Standardized questionnaires were used to collect information on residential fuel use for cooking and heating. Using unconditional logistic regression, we calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) for upper aerodigestive tract cancer risk after adjusting for potential confounders. RESULTS: Lifelong wood use was associated with pharyngeal and esophageal (OR 4.05, 95% CI: 1.30-12.68 and OR 2.71, 95% CI: 1.21-6.10, respectively). We observed an exposure-response relationship between duration of wood use and risk of pharyngeal cancer among those who had never used coal (P(trend)=0.04), ruling out the possibility of residual confounding by coal. Similarly, we observed an increased risk of laryngeal cancers and head & neck cancers among those who always used coal, with a noted exposure-response relationship (P(trend)<0.01). CONCLUSIONS: Our results suggest a possible role of indoor air pollution from solid fuel use in head and neck carcinogenesis in the high risk area of central and eastern Europe.

Occupational exposure to dusts and risk of renal cell carcinoma.

BACKGROUND: Occupational exposures to dusts have generally been examined in relation to cancers of the respiratory system and have rarely been examined in relation to other cancers, such as renal cell carcinoma (RCC). Although previous epidemiological studies, though few, have shown certain dusts, such as asbestos, to increase renal cancer risk, the potential for other occupational dust exposures to cause kidney damage and/or cancer may exist. We investigated whether asbestos, as well as 20 other occupational dust exposures, were associated with RCC risk in a large European, multi-center, hospital-based renal case-control study. METHODS: General occupational histories and job-specific questionnaires were reviewed by occupational hygienists for subject-specific information. Odds ratios (ORs) and 95% confidence intervals (95% CIs) between RCC risk and exposures were calculated using unconditional logistic regression. RESULTS: Among participants ever exposed to dusts, significant associations were observed for glass fibres (OR: 2.1; 95% CI: 1.1-3.9), mineral wool fibres (OR: 2.5; 95% CI: 1.2-5.1), and brick dust (OR: 1.5; 95% CI: 1.0-2.4). Significant trends were also observed with exposure duration and cumulative exposure. No association between RCC risk and asbestos exposure was observed. CONCLUSION: Results suggest that increased RCC risk may be associated with occupational exposure to specific types of dusts. Additional studies are needed to replicate and extend findings.

Occupation and renal cell cancer in Central and Eastern Europe.

OBJECTIVE: Central and Eastern Europe has among the highest rates of renal cell cancer worldwide. Few studies have been conducted in these areas to investigate the possible role of occupational exposures in renal cell cancer aetiology. The purpose of this study was to examine the association of renal cell cancer with employment in specific occupations and industries. METHODS: From 1999 to 2003, we conducted a hospital-based case-control study in seven areas of the Czech Republic, Poland, Romania and Russia. A detailed occupational history was collected from renal cell cancer cases and controls, together with information on potential confounders. Odds ratios (ORs) and 95% CI of cancer risk were calculated for having ever been employed in selected jobs and industries, with follow-up analyses examining duration of employment. RESULTS: A total of 992 histologically confirmed incident renal cell cancer cases and 1459 controls were included in the analysis. An increased risk of renal cell cancer was observed for workers in agricultural labour and animal husbandry (OR 1.43; 95% CI 1.05 to 1.93), particularly among women employed as general farm workers (OR 2.73; 95% CI 1.05 to 7.13). Risk gradients for agricultural work increased with longer employment. An overall increased risk of renal cell cancer was seen among architects and engineers (OR 1.89; 95% CI 1.35 to 2.65), and mechanical engineers (OR 1.71; 95% CI 1.03 to 2.84). CONCLUSIONS: Our data suggest an association between renal cell cancer and agricultural work, particularly among female workers.

Association between GPx1 Pro198Leu polymorphism, GPx1 activity and plasma selenium concentration in humans.

BACKGROUND: Glutathione peroxidase 1 (GPx1) is an antioxidant selenoenzyme that protects the cells against reactive oxygen species. Its activity depends on the concentration of selenium (Se) which is present in the active centre of the enzyme. The genetic polymorphism of GPx1 encoding gene (GPx1) associated with the proline (Pro) to leucine (Leu) change at codon 198 is supposed to be functional. An in vitro study performed on human breast carcinoma cell line showed that GPx1Leu allele was associated with a lower responsiveness of the enzyme to Se added to the culture medium. Some authors observed a decrease in GPx1 activity associated with GPx1 Leu allele in humans; however, there were no findings on how GPx1 activity changes with Se concentration in individuals with different GPx1 genotypes. AIM OF THE STUDY: To assess whether GPx1 activity that depends on the Se status may be influenced by GPx1 polymorphism through studying this relationship in the blood of healthy individuals. METHODS: The association between the Se status, GPx1 activity and GPx1 genotype was assessed in 405 individuals of Polish origin. GPx1 activity in red blood cells was measured by the spectrophotometric method by Paglia and Valentine, using t-butylhydroperoxide as the substrate. Plasma Se concentration was measured using graphite furnace atomic absorption spectrometry. GPx1 Pro198Leu polymorphism was determined with the Molecular Beacon Real-Time PCR assay. RESULTS: In the subjects examined, the mean plasma Se concentration was 54.4 +/- 14.2 mcg/L. The mean GPx1 activity was 15.1 +/- 4.7 U/g Hb. No difference regarding both the parameters was found between individuals with different GPx1 genotype. However, the association between GPx1 activity and Se concentration, analyzed separately for each genotype group, was not the same. The correlation coefficients amounted to r = 0.44 (p < 0.001) for Pro/Pro, r = 0.35 (p < 0.001) for Pro/Leu and r = 0.25 (p = 0.45) for Leu/Leu group, which indicates that the correlation strength was as follows: Pro/Pro > Pro/Leu > Leu/Leu. Notably, statistically significant difference in this relationship (analyzed as difference between correlation coefficients for linear trends) was found between genotypes Pro/Pro and Leu/Leu (p = 0.034). CONCLUSIONS: The findings of the present study provide evidence for the hypothesis based on in vitro studies which assumes that GPx1 Pro198Leu polymorphism has a functional significance for the human organism and that this functionality is associated with a different response of GPx1 activity to Se. They also point to the importance of the genetic background in the assessment of the Se status with the use of selenoprotein biomarkers such as GPx1 activity.

Renal cell carcinoma, occupational pesticide exposure and modification by glutathione S-transferase polymorphisms.

This study investigated associations between occupational pesticide exposure and renal cell carcinoma (RCC) risk. To follow-up on a previous report by Buzio et al., we also considered whether this association could be modified by glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) genotypes. About 1097 RCC cases and 1476 controls from Central and Eastern Europe were interviewed to collect data on lifetime occupational histories. Occupational information for jobs held for at least 12 months duration was coded for pesticide exposures and assessed for frequency and intensity of exposure. GSTM1 and GSTT1 gene deletions were analyzed using TaqMan assays. A significant increase in RCC risk was observed among subjects ever exposed to pesticides [odds ratio (OR): 1.60; 95% confidence interval (CI): 1.00-2.55]. After stratification by genotypes, increased risk was observed among exposed subjects with at least one GSTM1 active allele (OR: 4.00; 95% CI: 1.55-10.33) but not among exposed subjects with two GSTM1 inactive alleles compared with unexposed subjects with two inactive alleles (P-interaction: 0.04). Risk was highest among exposed subjects with both GSTM1 and GSTT1 active genotypes (OR: 6.47; 95% CI: 1.82-23.00; P-interaction: 0.02) compared with unexposed subjects with at least one GSTM1 or T1 inactive genotype. In the largest RCC case-control study with genotype information conducted to date, we observed that risk associated with pesticide exposure was exclusive to individuals with active GSTM1/T1 genotypes. These findings further support the hypothesis that glutathione S-transferase polymorphisms can modify RCC risk associated with occupational pesticide exposure.

Folate metabolism genes, vegetable intake and renal cancer risk in central Europe.

In a multicenter case-control study of renal cell carcinoma (RCC) conducted in central and eastern Europe, we reported a strong inverse association with high vegetable intake and RCC risk. The odds ratio (OR) for high compared to the lowest tertile of vegetable intake was OR = 0.67; (95% confidence interval (CI): 0.53-0.83; p-trend < 0.001). We hypothesized that variation in key folate metabolism genes may modify this association. Common variation in 5 folate metabolism genes (CBS: Ex9+33C > T (rs234706), Ex13 +41C > T (rs1801181), Ex18 -391 G > A (rs12613); MTHFR: A222V Ex5+79C > T (rs1801133), Ex8-62A > C (rs1801131); MTR: Ex26 20A > G (rs1805087), MTRR: Ex5+136 T > C (rs161870), and TYMS:IVS2-405 C > T (rs502396), Ex8+157 C > T (rs699517), Ex8+227 A > G (rs2790)) were analyzed among 1,097 RCC cases and 1,555 controls genotyped in this study. Having at least 1 variant T allele of MTHFR A222V was associated with higher RCC risk compared to those with 2 common (CC) alleles (OR = 1.44; 95% CI: 1.17-1.77; p = 0.001). After stratification by tertile of vegetable intake, the higher risk associated with the variant genotype was only observed in the low and medium tertiles (p-trend = 0.001), but not among those in the highest tertile (p-interaction = 0.22). The association remained robust after calculation of the false discovery rate (FDR = 0.05). Of the 3 TYMS SNPs examined, only the TYMS IVS2 -405 C (rs502396) variant was associated with a significantly lower risk compared to the common genotype (OR = 0.73; 95% CI: 0.57-0.93). Vegetable intake modified the association between all 3 TYMS SNPs and RCC risk (p-interaction < 0.04 for all). In summary, these findings suggest that common variation in MTHFR and TYMS genes may be associated with RCC risk, particularly when vegetable intake is low.

Tobacco smoking, body mass index, hypertension, and kidney cancer risk in central and eastern Europe.

In a case-control study of kidney cancer in four central European countries, with 1097 incident cases and 1476 controls, we found an increased risk for self-reported hypertension and for obesity. Additional unknown risk factors are likely to be responsible for the high rates of kidney cancer in this region.

Dietary risk factors for squamous cell carcinoma of the upper aerodigestive tract in central and eastern Europe.

OBJECTIVE: The incidence of squamous cell carcinoma of upper aerodigestive tract (UADT: oral cavity, pharynx, larynx, and esophagus) has been increasing in central and eastern European countries. We investigated the relationship between diet and UADT cancers in these high risk areas. METHODS: We used data from hospital-based case-control study of 948 UADT cancer cases and 1,228 controls conducted in Romania, Hungary, Poland, Russia, Slovakia, and Czech Republic. Standardized questionnaire were used to collect information on 23 different food items, along with alcohol and tobacco consumptions. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the UADT cancers after adjusting for center, age, sex, tobacco & alcohol intake, and other food groups. RESULTS: Consumption of dairy product was negatively associated with selected UADT cancers: larynx (OR: 0.38, CI: 0.23-0.62) and esophagus (OR: 0.55, CI: 0.33-0.93). While consumption of yellow/orange vegetables were inversely associated with oral/pharyngeal and laryngeal cancer (OR: 0.53, CI: 0.35-0.81 and OR: 0.62, CI: 0.38-1.00, respectively), preserved vegetable was positively associated with oral/pharyngeal and laryngeal cancer risk (p (trend) < 0.01 for both). CONCLUSION: Specific dietary components may play a role in the development of UADT cancers in the high-risk region of central and eastern Europe.

Vitamin D receptor polymorphisms and renal cancer risk in Central and Eastern Europe.

Previous studies investigated the role of vitamin D intake and cancer risk. The kidney is a major organ for vitamin D metabolism, activity, and calcium homeostasis; therefore, it was hypothesized that dietary vitamin D intake and polymorphisms in the vitamin D receptor (VDR) gene may modify renal cell carcinoma (RCC) risk. Three common VDR gene polymorphisms (BsmI, FokI, TaqI) were evaluated among 925 RCC cases and 1192 controls enrolled in a hospital-based case-control study conducted in Central and Eastern Europe. Overall associations with RCC risk were not observed; however, subgroup analyses revealed associations after stratification by median age of diagnosis and family history of cancer. Among subjects over 60 yr, reduced risks were observed among carriers of the f alleles in the FokI single-nucleotide polymorphism (SNP) (odds ratio [OR] = 0.61 for Ff and OR = 0.74 for ff genotypes) compared to subjects with the FF genotype (P trend = 0.04; P interaction = 0.004). Subjects with the BB BsmI genotype and a positive family history of cancer had lower risk compared to subjects with the bb allele (OR = 0.60; 95% CI: 0.33-1.1; P trend = 0.05). Genotype associations with these subgroups were not modified when dietary sources of vitamin D or calcium were considered. Additional studies of genetic variation in the VDR gene are warranted.

Elaboration of a quantitative job-exposure matrix for historical exposure to airborne exposures in the Polish rubber industry.

BACKGROUND: A job-exposure matrix (JEM) for inhalable aerosols, aromatic amines, and cyclohexane soluble matter (CSM) was elaborated based on measurements collected routinely between 1981 and 1996. METHODS: The data were grouped based on similarities in exposure levels and time trends in different departments, and were analyzed using smoothing splines and mixed effects models. RESULTS: Although higher than in western European countries, inhalable aerosol exposure decreased after changes in production volume and implementation of exposure reduction measures in mid-1980s. Aromatic amines concentrations first increased following the factory's production volume, but subsequently decreased in more recent years. CSM concentrations were uniformly distributed between departments. CONCLUSIONS: This JEM provides an overview of historical exposure levels in a large Polish rubber factory and will enable estimation of lifetime exposure for individual workers in a Polish rubber workers cohort and further investigation of the associations between specific exposures and cancer risk.

Mesothelioma continues to increase even 40 years after exposure - Evidence from long-term epidemiological observation.

BACKGROUND: Because asbestos dust is considered one of the most dangerous types of dust for people's health, issues related to the effects of asbestos exposure still remain questions about the role of cessation of exposure. OBJECTIVES: The aim of the present study was to determine the importance of temporal patterns, especially the time since the end of exposure in the risk of pleural mesothelioma. METHODS: A total of 131 patients with pleural mesothelioma and 655 frequency matched by gender and year of birth controls enrolled in the health surveillance programme for asbestos-related diseases over the years 2000-2014, were included in the analysis. Conditional logistic regression models were applied to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: The results show that the risk of pleural mesothelioma continued to increase even after 40 years since the last exposure. The estimated odds ratio for the subjects who had their last exposure 40 years ago, compared with the odds ratio of those who had their last exposure 5 years ago, was 2.68 (95%CI: 1.16-.621). We also observed that crocidolite exposure was associated with a very high significant mesothelioma risk, 5-fold higher for those working with mixed exposure compared to the subjects who worked only with chrysotile. CONCLUSIONS: Dose-response relationships in populations occupationally exposed are critical to the study related to environment asbestos contamination. Our findings confirm the strong evidence that mesothelioma risk increases along with the increasing time since exposure termination.

Genome-wide analysis implicates microRNAs and their target genes in the development of bipolar disorder.

Bipolar disorder (BD) is a severe and highly heritable neuropsychiatric disorder with a lifetime prevalence of 1%. Molecular genetic studies have identified the first BD susceptibility genes. However, the disease pathways remain largely unknown. Accumulating evidence suggests that microRNAs, a class of small noncoding RNAs, contribute to basic mechanisms underlying brain development and plasticity, suggesting their possible involvement in the pathogenesis of several psychiatric disorders, including BD. In the present study, gene-based analyses were performed for all known autosomal microRNAs using the largest genome-wide association data set of BD to date (9747 patients and 14 278 controls). Associated and brain-expressed microRNAs were then investigated in target gene and pathway analyses. Functional analyses of miR-499 and miR-708 were performed in rat hippocampal neurons. Ninety-eight of the six hundred nine investigated microRNAs showed nominally significant P-values, suggesting that BD-associated microRNAs might be enriched within known microRNA loci. After correction for multiple testing, nine microRNAs showed a significant association with BD. The most promising were miR-499, miR-708 and miR-1908. Target gene and pathway analyses revealed 18 significant canonical pathways, including brain development and neuron projection. For miR-499, four Bonferroni-corrected significant target genes were identified, including the genome-wide risk gene for psychiatric disorder CACNB2. First results of functional analyses in rat hippocampal neurons neither revealed nor excluded a major contribution of miR-499 or miR-708 to dendritic spine morphogenesis. The present results suggest that research is warranted to elucidate the precise involvement of microRNAs and their downstream pathways in BD.

Occupational cancer in central European countries.

The countries of central Europe, including Poland, the Czech Republic, Slovakia, Hungary, Romania, and Bulgaria, suffer from environmental and occupational health problems created during the political system in place until the late 1980s. This situation is reflected by data on workplace exposure to hazardous agents. Such data have been systematically collected in Skovakia and the Czech Republic since 1977. The data presented describe mainly the situation in the early 1990s. The number of workers exposed to risk factors at the workplace represent about 10% of the working population in Slovakia and 30% in Poland. In Slovakia in 1992 the percentage of persons exposed to chemical substances was 16.4%, to ionizing radiation 4.3%, and to carcinogens 3.3% of all workers exposed to risk factors. The total number of persons exposed to substances proven to be carcinogens in Poland was 1.3% of the employees; 2.2% were exposed to the suspected carcinogens. The incidence of all certified occupational diseases in the Slovak Republic was 53 per 100,000 insured employees in 1992. Cancers certified as occupational cancers are skin cancer caused by occupational exposure to carcinogens, lung cancer caused by ionizing radiation, and asbestosis together with lung cancer. Specific information on occupational cancers from Romania and Bulgaria was not available for this paper. It is difficult to predict a trend for future incidences of occupational cancer. Improved control technology, governmental regulatory activity to reduce exposure, surveillance of diseases and risk factors, and vigilant use of preventive measures should, however, ultimately reduce occupational cancer.

Glutathione S-transferase M1 and P1 metabolic polymorphism and lung cancer predisposition.

Individual susceptibility to different environmental agents is expected to be associated with alterations in metabolism of xenobiotics. Thus, genetic polymorphism of glutathione S-transferase (GST) can be recognized as a potential risk modifier in lung cancer development. The distribution of GSTM1 and GSTP1 genotypes was studied in a group of 138 diagnosed lung cancer patients and in 165 controls living in central Poland and RFLP-PCR technique was applied. The frequency of GSTM1 null genotype and GSTP1 Val single and duplicated alleles was similar among patients and controls. GSTM1 homozygous deletion was most prevalent in small-cell carcinoma groups (adjusted odds ratio (OR): 2.32, 95% confidence interval (CI): 0.98-5.52). In patients and controls, GSTM1A genotype was most frequent (34.1% vs. 37.0%). The estimated lung cancer risk for GSTM1 null, GSTP1 Ile/Val and GSTP1 Val/Val combined genotype was 1.44 (95% CI: 0.73-2.83), suggesting the absence of modifying effect of defective GSTM1 and GSTP1 alleles on lung cancer predisposition.

Oxidative-stress markers in blood of lung cancer patients occupationally exposed to carcinogens.

The study covered 152 lung cancer patients and 210 controls. The results of the study indicated decreased selenium (Se) concentrations and lowered activity of erythrocyte antioxidant enzymes (glutathione peroxidase, superoxide dismutase, glutathione-S-transferase) in the blood of lung cancer patients, as well as significantly increased concentrations of vitamin E in erythrocytes and thiobarbituric acid reactive substances in the plasma of the study population. Low plasma Se concentrations (< 45.7 microg/L) enhance the estimated risk of lung cancer (odds ratio = 3.047, p < 0.001). A more precise exposure assessment is required to identify the association between lung cancer incidence and occupational exposure to carcinogens.

Mortality of workers at two asbestos-cement plants in Poland.

To assess mortality rate among workers occupationally exposed to asbestos, cohort studies were carried out in two asbestos cement plants operating since the 1960s. Asbestos cement sheets for roofing and siding have been manufactured there, using mostly chrisotile, and since 1985 also crocidolite for pressure pipes. In all, the cohort comprised 3,220 workers, including 2,616 male workers. Subject to consideration were the workers employed for at least three months in the period between the onset of the production and 1980. The vital status of the subjects was traced up to 31 December 1991. The availability of the cohort was 96.8%. Workers' mortality was analysed using standardized mortality ratio (SMR). The reference group was the general population of Poland. In the male cohort, 385 cases of death were recorded. Statistically significant excess of mortality from large intestine cancer (7 cases, SMR = 264) and pleural mesothelioma (5 cases, SMR = 2846) was found. In male workers who died from pleural mesothelioma the work history ranged from 12 to 26 years. An excess mortality from pleural mesothelioma was also noted among the female workers (2 cases, SMR = 11,275). No malignant neoplasms of other locations produced significant excess mortality either in the male or female workers.

Sickness absence in a rubber plant in Poland.

The disease-related temporary incapacity for work, its causes and duration are essential factors in the assessment of health status of the occupationally active population. The aim of the present study was to investigate the main causes of work disability among the rubber industry workers, with special regard to sickness absence among workers directly enganged in manufacture. The study was performed in 1995 on a sample of 973 workers (456 males and 517 females) at a plant producing rubber footware. The number of days of work disability from a particular disease, frequency and duration per year were examined. The analysis concerned such parameters of sickness absence as the lost time rate, average duration of absence, and percentage of workers on a sick-leave. The results revealed that during the period under study the main medical causes of the sickness absence included: a) for males--cardiovascular diseases (48% of the total sickness absence), respiratory diseases (18%), gastrointestinal disease (8%) and the nervous system and sense organs diseases (8%); b) for females--cardiovascular diseases (24%), respiratory diseases (16%), pregnancy, childbirth and puerperium complications (11%) and neoplasms (10%). The sickness absence of workers directly involved in the manufacture appeared to be by 72% higher than that noted for workers of other departments, with the age- and gender-standardized lost time rate of 4.74. The differences can be related mainly to a higher percentage of the sick in the group of 'production workers' (43%) as compared to the 'non-production' ones (28%). The findings of our study indicate that in the rubber industry workers a high rate of absence due to some groups of diseases may be associated with exposure to hazardous agents in their work environment.

Mortality pattern in the cohort of workers exposed to carbon disulfide.

The objective of the study was to assess mortality in the cohort of the viscose factory workers occupationally and environmentally exposed to carbon disulfide. Male workers employed for at least one year during 1950-1985 in the production or maintenance departments, living in the vicinity of the plant, were enrolled into the study. Of the 2,878 workers in the cohort, 2,762 were successfully traced, yielding 76,465 person-years. Mortality assessment was based on the standardized mortality ratio using a person-years method. The general male population of Poland was considered as a reference group. Total mortality in the cohort was higher than in the general male population in Poland (SMR = 108). A significantly increased risk of deaths was observed for all cardiovascular (SMR = 114) and cerebrovascular (SMR = 208) diseases. Analyses showed a significantly elevated risk of death from the circulatory system diseases in the men of the "highly exposed" group, spinners and those who were first employed before 1974. A statistically significant trend of mortality from all cardiovascular diseases in relation to the level of exposure (assessed qualitatively) was evident. No clear relationship between duration of exposure and the risk of death was found.

Mortality in the cotton industry workers: results of a cohort study.

The cohort consisted of persons found on the payroll of one of the Lódz cotton plants in 1964-1993 who were employed in the plant for at least 10 years. Death risk by causes was analysed using standardised mortality ratios (SMRs) calculated by the person-years method. The general population of Poland was used as the reference. In all, 7892 people were observed. As of December 31, 1995, the follow-up was completed for 7545 people (2852 men and 4693 women), i.e. the availability of the cohort was 95.6%. A total of 2069 deaths were recorded; the information on the cause of death was available for 97% of the subjects. In the male cohort, the level of the general mortality was the same as in the general population (SMR = 99). However, there was a significant increase in the number of deaths from diseases of the digestive system (SMR = 142) and larynx cancer (SMR = 188). The analysis of the results by production departments revealed in the weaving department significantly higher mortality from atherosclerosis (SMR = 141), peritoneal carcinoma (SMR = 1057) and melanoma (SMR = 677); and in the spinning department the increased risk of the hypertensive disease (SMR = 239), atherosclerosis (SMR = 175), and Hodgkin's disease (SMR = 768). Mortality in the female cohort was lower than that in the general population (SMR = 88). None of the disease groups or tumour sites caused statistically significant excess deaths either in the total cohort or in subcohorts selected according to departments. Special attention was paid to the chemical processing departments where chemicals used could contribute to the increased risk of death from cancer. Our analysis did not reveal any significant increase either in the total cohort of the workers employed in those departments or in the cohorts analyzed by duration of employment. Our results confirm the lower risk of lung cancer in the analysed group as compared with that in the general population. The numerous, but statistically insignificant increases in the incidence of malignant tumours at some specific sites detected in the subcohorts, distinguished according to the duration of employment or department, confirm the reported findings on the incidence of oral cavity, nose, throat, and larynx tumours among people exposed to harmful agents in the cotton industry.