9 research outputs found
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 1970–2010 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
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 1970a(sic)'' 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
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
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\u2009801 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
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
[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
Italian pool of asbestos workers cohorts: mortality trends of asbestos-related neoplasms after long time since first exposure
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
Factors Affecting Asbestosis Mortality Among Asbestos-Cement Workers in Italy
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
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