Rate advancement measurement for lung cancer and pleural mesothelioma in asbestos-exposed workers

INTRODUCTION

Exposure to asbestos increases the risk of lung cancer and mesothelioma. Few studies quantified the premature occurrence of these diseases in asbestos-exposed workers. Focus on premature disease onset (rate advancement or acceleration) can be useful in risk communication and for the evaluation of exposure impact. We estimated rate advancement for total mortality, lung cancer and pleural mesothelioma deaths, by classes of cumulative asbestos exposure in a pooled cohort of asbestos cement (AC) workers in Italy.

METHOD

The cohort study included 12 578 workers from 21 cohorts, with 6626 deaths in total, 858 deaths from lung cancer and 394 from pleural malignant neoplasm (MN). Rate advancement was estimated by fitting a competitive mortality Weibull model to the hazard of death over time since first exposure (TSFE).

RESULT

Acceleration time (AT) was estimated at different TSFE values. The highest level of cumulative exposure compared with the lowest, for pleural MN AT was 16.9 (95% CI 14.9 to 19.2) and 33.8 (95% CI 29.8 to 38.4) years at TSFE of 20 and 40 years, respectively. For lung cancer, it was 13.3 (95% CI 12.0 to 14.7) and 26.6 (95% CI 23.9 to 29.4) years, respectively. As for total mortality, AT was 3.35 (95% CI 2.98 to 3.71) years at 20 years TSFE, and 6.70 (95% CI 5.95 to 7.41) at 40 years TSFE.

CONCLUSION

The current study observed marked rate advancement after asbestos exposure for lung cancer and pleural mesothelioma, as well as for total mortality.

Italian pool of asbestos workers cohorts: asbestos related mortality by industrial sector and cumulative exposure

OBJECTIVE

Italy has been a large user of asbestos and asbestos containing materials until the 1992 ban. We present a pooled cohort study on long-term mortality in exposed workers.

METHODS

Pool of 43 Italian asbestos cohorts (asbestos cement, rolling stock, shipbuilding, glasswork, harbors, insulation and other industries). SMRs were computed by industrial sector for the 1970-2010 period, for the major causes, using reference rates by age, sex, region and calendar period.

RESULTS

The study included 51 801 subjects (5741 women): 55.9% alive, 42.6% died (cause known for 95%) and 1.5% lost to follow-up. Asbestos exposure was estimated at the plant and period levels. Asbestos related mortality was significantly increased. All industrial sectors showed increased mortality from pleural malignancies, and most also from peritoneal and lung cancer and asbestosis, with exposure related trend. Increased mortality was also observed for ovarian cancer and for bladder cancer.

DISCUSSION

The study confirmed the increased risk for cancer of the lung, ovary, pleura and peritoneum but not of the larynx and the digestive tract. A large increase in mortality from asbestosis was observed.

Factors Affecting Asbestosis Mortality Among Asbestos-Cement Workers in Italy

OBJECTIVES

This study was performed with the aim of investigating the temporal patterns and determinants associated with mortality from asbestosis among 21 cohorts of Asbestos-Cement (AC) workers who were heavily exposed to asbestos fibres.

METHODS

Mortality for asbestosis was analysed for a cohort of 13 076 Italian AC workers (18.1% women). Individual cumulative asbestos exposure index was calculated by factory and period of work weighting by the different composition of asbestos used (crocidolite, amosite, and chrysotile). Two different approaches to analysis, based on Standardized Mortality Ratios (SMRs) and Age-Period-Cohort (APC) models were applied.

RESULTS

Among the considered AC facilities, asbestos exposure was extremely high until the end of the 1970s and, due to the long latency, a peak of asbestosis mortality was observed after the 1990s. Mortality for asbestosis reached extremely high SMR values [SMR: males 508, 95% confidence interval (CI): 446-563; females 1027, 95% CI: 771-1336]. SMR increased steeply with the increasing values of cumulative asbestos exposure and with Time Since the First Exposure. APC analysis reported a clear age effect with a mortality peak at 75-80 years; the mortality for asbestosis increased in the last three quintiles of the cumulative exposure; calendar period did not have a significant temporal component while the cohort effect disappeared if we included in the model the cumulative exposure to asbestos.

CONCLUSIONS

Among heaviest exposed workers, mortality risk for asbestosis began to increase before 50 years of age. Mortality for asbestosis was mainly determined by cumulative exposure to asbestos.

Role of asbestos clearance in explaining long-term risk of pleural and peritoneal cancer: a pooled analysis of cohort studies

OBJECTIVES

Models based on the multistage theory of cancer predict that rates of malignant mesothelioma continuously increase with time since first exposure (TSFE) to asbestos, even after the end of external exposure. However, recent epidemiological studies suggest that mesothelioma rates level off many years after first exposure to asbestos. A gradual clearance of asbestos from the lungs has been suggested as a possible explanation for this phenomenon. We analysed long-term trends of pleural and peritoneal cancer mortality in subjects exposed to asbestos to evaluate whether such trends were consistent with the clearance hypothesis.

METHODS

We used data from a pool of 43 Italian asbestos cohorts (51 801 subjects). The role of asbestos clearance was explored using the traditional mesothelioma multistage model, generalised to include a term representing elimination of fibres over time.

RESULTS

Rates of pleural cancer increased until 40 years of TSFE, but remained stable thereafter. On the other hand, we observed a monotonic increase of peritoneal cancer with TSFE. The model taking into account asbestos clearance fitted the data better than the traditional one for pleural (p=0.004) but not for peritoneal (p=0.09) cancer.

CONCLUSIONS

Rates of pleural cancer do not increase indefinitely after the exposure to asbestos, but eventually reach a plateau. This trend is well described by a model accounting for a gradual elimination of the asbestos fibres. These results are relevant for the prediction of future rates of mesothelioma and in asbestos litigations.

Cumulative asbestos exposure and mortality from asbestos related diseases in a pooled analysis of 21 asbestos cement cohorts in Italy

BACKGROUND

Despite the available information on cancer risk, asbestos is used in large areas in the world, mostly in the production of asbestos cement. Moreover, questions are raised regarding the shape of the dose response relation, the relation with time since exposure and the association with neoplasms in various organs. We conducted a study on the relationship between cumulative asbestos exposure and mortality from asbestos related diseases in a large Italian pool of 21 cohorts of asbestos-cement workers with protracted exposure to both chrysotile and amphibole asbestos.

METHODS

The cohort included 13,076 workers, 81.9% men and 18.1% women, working in 21 Italian asbestos-cement factories, with over 40 years of observation. Exposure was estimated by plant and period, and weighted for the type of asbestos used. Data were analysed with consideration of cause of death, cumulative exposure and time since first exposure (TSFE), and by gender. SMRs were computed using reference rates by region, gender and calendar time. Poisson regression models including cubic splines were used to analyse the effect of cumulative exposure to asbestos and TSFE on mortality for asbestos-related diseases. 95% Confidence Intervals (CI) were computed according to the Poisson distribution.

RESULTS

Mortality was significantly increased for 'All Causes' and 'All Malignant Neoplasm (MN)', in both genders. Considering asbestos related diseases (ARDs), statistically significant excesses were observed for MN of peritoneum (SMR: men 14.19; women 15.14), pleura (SMR: 22.35 and 48.10), lung (SMR: 1.67 and 1.67), ovary (in the highest exposure class SMR 2.45), and asbestosis (SMR: 507 and 1023). Mortality for ARDs, in particular pleural and peritoneal malignancies, lung cancer, ovarian cancer and asbestosis increased monotonically with cumulative exposure. Pleural MN mortality increased progressively in the first 40 years of TSFE, then reached a plateau, while peritoneal MN showed a continuous increase. The trend of lung cancer SMRs also showed a flattening after 40 years of TSFE. Attributable proportions for pleural, peritoneal, and lung MN were respectively 96, 93 and 40%.

CONCLUSIONS

Mortality for ARDs was associated with cumulative exposure to asbestos. Risk of death from pleural MN did not increase indefinitely with TSFE but eventually reached a plateau, consistently with reports from other recent studies.

Italian pool of asbestos workers cohorts: mortality trends of asbestos-related neoplasms after long time since first exposure

OBJECTIVE

Asbestos is a known human carcinogen, with evidence for malignant mesothelioma (MM), cancers of lung, ovary, larynx and possibly other organs. MM rates are predicted to increase with a power of time since first exposure (TSFE), but the possible long-term attenuation of the trend is debated. The asbestos ban enforced in Italy in 1992 gives an opportunity to measure long-term cancer risk in formerly exposed workers.

METHODS

Pool of 43 previously studied Italian asbestos cohorts (asbestos cement, rolling stock, shipbuilding), with mortality follow-up updated to 2010. SMRs were computed for the 1970â€"2010 period, for the major causes, with consideration of duration and TSFE, using reference rates by age, sex, region and calendar period.

RESULTS

The study included 51 801 subjects (5741 women): 55.9% alive, 42.6% died (cause known for 95%) and 1.5% lost to follow-up. Mortality was significantly increased for all deaths (SMR: men: 1.05, 95% CI 1.03 to 1.06; women: 1.17, 95% CI to 1.12 to 1.22), all malignancies combined (SMR: men: 1.17, 95% CI to 1.14 to 1.20; women: 1.33, 95% CI 1.24 to 1.43), pleural and peritoneal malignancies (SMR: men: 13.28 and 4.77, 95% CI 12.24 to 14.37 and 4.00 to 5.64; women: 28.44 and 6.75, 95% CI 23.83 to 33.69 and 4.70 to 9.39), lung (SMR: men: 1.26, 95% CI 1.21 to 1.31; women: 1.43, 95% CI 1.13 to 1.78) and ovarian cancer (SMR=1.38, 95% CI 1.00 to 1.87) and asbestosis (SMR: men: 300.7, 95% CI 270.7 to 333.2; women: 389.6, 95% CI 290.1 to 512.3). Pleural cancer rate increased during the first 40 years of TSFE and reached a plateau after.

DISCUSSION

The study confirmed the increased risk for cancer of the lung, ovary, pleura and peritoneum but not of the larynx and the digestive tract. Pleural cancer mortality reached a plateau at long TSFE, coherently with recent reports.

[Time trend in mesothelioma and lung cancer risk in asbestos workers in Italy]

This study aims at investigating, in asbestos exposed workers, the time trend of their risk of mesothelioma and of other neoplasm after very long latency and after the cessation of asbestos exposure. We pooled a large number of Italian cohorts of asbestos workers and updated mortality follow-up. The pool of data for statistical analyses includes 51,988 workers, of which 6,058 women: 54.2% was alive at follow-up, 42.6% was dead, and 2.8%was lost. Cause of death is known for 94.3%: 2,548 deaths from lung cancer, 748 frompleural cancer, 173 fromperitoneal cancer, and 434 from asbestosis. An exposure index is being developed to compare the different cohorts. Data analysis is in progress. This study will have the size for analysing not only time trends in mesothelioma, but also the occurrence of rarer diseases and cancer specific mortality in women.

[Asbestos-related diseases in former asbestos-cement workers in Senigallia]

BACKGROUND

A factory that produced asbestos-cement products, using chrysotile, amosite and crocidolite in very low percentages, cement and water, operated in Senigallia from 1948 to 1984. Workers and residents still living in Senigallia are 238.

OBJECTIVES

The need for an organic response to requests by former workers for protection of health and recognition of occupational diseases induced the Prevention and Safety at the Workplace Service in Senigallia/Area Vasta 2 to implement a programme of health surveillance.

METHODS

In 2010 a health surveillance programme was initiated that involved 158 subjects, 58 women and 100 men. The average age of men was 75 years and 70 for women. The time elapsed between first exposure and participation in the programme was on average 50 years (SD 7.49). The average number of years of exposure to asbestos fibres was 17 (SD 10.36). The programme included counselling activities, especially as regards cessation of smoking, and first and second level health checks.

RESULTS

The health surveillance programme enabled us to diagnose pleural plaques and pleural thickening in 81% of the subjects and various degrees of interstitial abnormalities in 49.4%. The high percentage of asbestos-related diseases was connected mainly with the long latency of the population under study and the higher diagnostic sensitivity of low dose chest CT scan applied to these diseases.

CONCLUSIONS

In our experience, in order to optimize the benefits of a health surveillance programme of former workers exposed to asbestos, it will be advisable to define parameters of access to the programme for individual subjects in relation to life expectancy, clinical conditions, time elapsed since first exposure, time of cessation of exposure. Such parameters, together with any risk factors, will influence the diagnostic process.

[Protection of working mothers: operational guide document. The Marche Regional Section of the Italian Society of Occupational Health and Industrial Hygiene (SIMLII) ]

Protection of working mothers: operational guide document. The aim of this operational guide document is to protect the health of working mothers and their babies during pregnancy, puerperium and breastfeeding. The project was developed by a technical working group which included professionals in the pertinent fields from the Workplace Prevention and Safety Services of the local Vasta-2 Area of the Marche Regional Health Service:physicians, health assistants, and nurses. It is considered to be a useful tool for risk assessment at the workplace aimed at professionals who are involved, with various duties and responsibilities, in the health care of the working mother. This paper consists of two functionally related sections, "Table of risks" and "Technical specifications". In the "Table of Risks" section, the occupational hazards for women during pregnancy or postpartum were analyzed with the highest possible degree of care. To this end the technical group provided, for each occupational hazard, its own operational suggestions, in relation to legislation, current scientific knowledge and Guidelines of other Italian Regions. The Marche Regional Section of the Italian Society of Occupational Health and Industrial Hygiene (SIMLII) participated in the final draft of the entire document. The second section, "Technical Specifications", illustrates the main tasks and any risks involved in the 34 manufacturing sectors most prevalent in this area. This operational guide document is intended to be the beginning of a common strategy in public health to achieve a wider field of action in promotion and information aimed at protecting the reproductive health of working mothers.

[Mortality of workers employed at an asbestos cement manufacturing plant in Senigallia]

The mortality (1948-1990) was investigated in 561 workers employed in an asbestos cement plant in Senigallia (Central Italy). A significant increase in lung cancer was observed in male subjects (SMR: 276; 95% C.I.: 175.2-414.8, 23 observed). The excess mortality was a function of the induction-latency time. Five deaths were observed among women, one of which due to malignant pleural neoplasm.

Ring chromosome 5 associated with severe growth retardation as the sole major physical abnormality

We report on a case of ring chromosome 5 in a 36-month-old girl with severe growth retardation, clinodactyly, mild psychological abnormalities, and normal facial appearance. Endocrine tests showed partial growth hormone deficiency. Cytogenetic investigation failed to demonstrate any apparent microscopic deletion of either short or long arm of chromosome 5 as consequence of ring formation. In 12% of cells examined, the ring was either absent or present in multiple copies. Only 3 previous cases of ring chromosome 5 have been reported in association with short stature of prenatal onset and minor anomalies, without mental retardation.