An occupational cohort mortality study of women in the German rubber industry: 1976 to 1991

Prediction of lung cancer risk using circulating pro-surfactant protein B and high-sensitivity C-reactive protein among Egyptian workers in the rubber industry

OBJECTIVE

For several decades, there has been increasing evidence for excess incidence of lung cancer among workers in the rubber industry. The purpose of this study was to assess the risk of lung cancer occurrence among Egyptian workers involved in the rubber industry using two circulating protein biomarkers.

METHODS

This study was performed in a rubber manufacturing factory in Shubra El-Kheima region in Greater Cairo, Egypt. Environmental assessment for the suspended particulate matter of size 10 µm (PM10) concentrations was done. Levels of plasma pro-surfactant protein B (pro-SFTPB) and serum high-sensitivity C-reactive protein (HsCRP) were measured among the studied population (n = 155) who were divided into two groups. The first group included 75 workers exposed to rubber manufacturing process while the control group involved 80 administrative subjects.

RESULTS

The levels of PM10 neither exceeded the Egyptian nor the international permissible limits where the highest levels were observed in the mixing department. However, through medical history and clinical examination, it was observed that some general and respiratory manifestations were more prevalent among the exposed group when compared with their controls. Laboratory investigations revealed that the mean values of pro-SFTPB and HsCRP levels among exposed workers were significantly higher than those of the control group. These increased circulating proteins levels were strongly and positively correlated with each other and with the duration of employment of exposed workers.

CONCLUSION

The study results support the conclusion that prolonged occupational exposure to rubber manufacturing process is associated with an elevated risk of lung cancer.

Extended cancer mortality follow-up of a German rubber industry cohort

OBJECTIVE

We extended follow-up of a cohort of German rubber industry workers (active or retired in 1981) by 9 years (1992 to 2000) to reassess previously observed cancer mortality risks.

METHODS

We calculated standardized mortality ratios and stratified results by work area, duration of employment, and year of hire.

RESULTS

The cohort includes 11,632 men and 1863 women from five tire or general rubber goods producing factories. Among men we observed significantly elevated standardized mortality ratios for cancers of the lung and the pleura in the full cohort and in specific strata. Among women we observed a significantly elevated standardized mortality ratio for cancer of the lung.

CONCLUSIONS

We observed excess risk for several cancer sites among men and women. Further cancer risk analysis of workers in the rubber industry should focus on differences in work areas and associated exposures.

Occupational exposure and lung cancer

Lung cancer is the leading cause of cancer death for male and the second most usual cancer for women after breast cancer. Currently there are available several non-specific cytotoxic agents and several targeted agents for lung cancer therapy. However; early stage diagnosis is still unavailable and several efforts are being made towards this direction. Novel biomarkers are being investigated along with new biopsy techniques. The occupational and environmental exposure to carcinogenic agents is an everyday phenomenon. Therefore until efficient early diagnosis is available, avoidance of exposure to carcinogenic agents is necessary. In the current mini-review occupational and environmental carcinogenic agents will be presented.

Cancer incidence and mortality in a Swedish rubber tire manufacturing plant

BACKGROUND

A classification of 12 work categories was used to evaluate the cancer incidence and mortality among a cohort of Swedish rubber tire workers.

METHODS

Cancer incidence and mortality in the cohort was compared with expected values from national rates. Standardized incidence and mortality ratios were calculated for the total cohort, for sub-cohorts and with the inclusion of a latency requirement.

RESULTS

Among men, increased incidence and mortality risks were found for cancer in the larynx; SIR=2.10; 95% confidence intervals (95% CI): 1.05-3.76, SMR=2.08; 95% CI: 0.42-6.09. Increased risks were also seen for cancer in the trachea, bronchus, and lung; SIR=1.62; 95% CI: 1.28-2.02, SMR=1.54; 95% CI: 1.21-1.94, the incidence risk was highest among those with the longest exposure duration and among workers in compounding/mixing, milling, and maintenance. Decreased incidence risks were seen for cancer of the prostate (SIR=0.74; 95% CI: 059-0.92) and skin (SIR=0.57; 95% CI: 0.36-0.84).

CONCLUSIONS

The finding of an excess of tumors in the respiratory system is in agreement with earlier findings in other studies on rubber tire workers. The results on other cancer types are compared to earlier findings and related to work processes and chemical exposures of possible causal importance.

Mortality and cancer incidence among tire manufacturing workers hired in or after 1962

OBJECTIVE

This study evaluated mortality during 1962 through 2003 and cancer incidence during 1995 through 2003 at a tire manufacturing plant.

METHODS

The mortality study included 3425 men and women, employed for at least one year. Of these, 3069 were eligible for the cancer incidence study.

RESULTS

Employees experienced 390 deaths compared with 608 expected (standardized mortality ratio (SMR)=64; 95% confidence interval (CI)=58-71). Total cancer mortality (123 observed, SMR=75, CI=62-89) and lung cancer mortality (47 observed, SMR=72, CI=53-96) were lower than expected. Hourly white men had small increases in stomach cancer, bladder cancer, and leukemia deaths. During 1995 through 2003, 169 incident cancers were observed compared with 197 expected (SIR=86, 95% CI=74-100). Three mesothelioma cases occurred among hourly white men (SIR=653, CI=135-1907); all were exposed potentially to asbestos before starting at the rubber plant.

CONCLUSIONS

Small numbers and limited information on jobs, occupational agents, and lifestyle preclude attribution of observed increases to workplace exposures.

Mortality in a Swedish rubber tire manufacturing plant: occupational risks or an "unhealthy worker" effect?

BACKGROUND

In this cohort study a classification of 12 work categories, with specified common exposures, is used to evaluate the mortality among workers in a Swedish rubber tire plant.

METHODS

Mortality among the cohort members is compared with expected values from national rates. Standardized mortality ratios (SMR) were calculated for the total cohort, for sub-cohorts and with the inclusion of a latency requirement.

RESULTS

Male workers had increased risks for total mortality, circulatory death, respiratory death, mental disorders, epilepsy, injuries/poisoning, and for alcohol-related death. Many risks were noted among workers exposed to dust, fumes, or vapor. No trend in risk with increasing duration of employment was seen.

DISCUSSION

Some established risks for rubber workers could be related to some specified work categories. The highest risks were noted among workers having a very short duration of employment indicating a possible "unhealthy worker effect" associated with life-style factors or to tasks offered to unskilled workers.