Epidemiologic evidence of cancer risk in textile industry workers: a review and update

Colorectal cancer incidence among female textile workers in Shanghai, China: a case-cohort analysis of occupational exposures

Previous studies have suggested increased risks of colorectal cancers among textile industry workers, potentially related to synthetic fibers. To investigate risks of colon and rectum cancers in relation to these and other textile industry exposures, we conducted a case-cohort study nested within a cohort study of female employees from the Shanghai Textile Industry Bureau (STIB). Cox proportional hazard regression modeling was used to estimate hazard ratios (HR) for colon and rectum cancers associated with duration of employment (e.g., 0, >0 to <10, 10 to <20 years, > or =20 years) in various jobs classified according to process type and exposures to specific agents. Our findings indicate that certain long term exposures may pose increased risk of colorectal cancers, especially dyes and dye intermediates with colon cancer (> or =20 years exposure versus never, HR=3.9; 95% CI: 1.4-10.6), and maintenance occupation (HR = 2.3; 95% CI: 1.0-5.7) and metals exposure (HR = 2.0; 95% CI: 1.1-3.6) with rectum cancer. A decreased risk of rectum cancer was associated with exposure to natural fibers such as cotton (HR = 0.7; 95% CI: 0.5-0.9), and a trend of decreasing rectum cancer incidence was observed by category of cumulative quantitative cotton dust or endotoxin exposures, when exposures were lagged by 20 years.

Municipal distribution of bladder cancer mortality in Spain: possible role of mining and industry

Background

Spain shows the highest bladder cancer incidence rates in men among European countries. The most important risk factors are tobacco smoking and occupational exposure to a range of different chemical substances, such as aromatic amines.

Methods

This paper describes the municipal distribution of bladder cancer mortality and attempts to "adjust" this spatial pattern for the prevalence of smokers, using the autoregressive spatial model proposed by Besag, York and Molliè, with relative risk of lung cancer mortality as a surrogate.

Results

It has been possible to compile and ascertain the posterior distribution of relative risk for bladder cancer adjusted for lung cancer mortality, on the basis of a single Bayesian spatial model covering all of Spain's 8077 towns. Maps were plotted depicting smoothed relative risk (RR) estimates, and the distribution of the posterior probability of RR>1 by sex. Towns that registered the highest relative risks for both sexes were mostly located in the Provinces of Cadiz, Seville, Huelva, Barcelona and Almería. The highest-risk area in Barcelona Province corresponded to very specific municipal areas in the Bages district, e.g., Suría, Sallent, Balsareny, Manresa and Cardona.

Conclusion

Mining/industrial pollution and the risk entailed in certain occupational exposures could in part be dictating the pattern of municipal bladder cancer mortality in Spain. Population exposure to arsenic is a matter that calls for attention. It would be of great interest if the relationship between the chemical quality of drinking water and the frequency of bladder cancer could be studied.

Occupational risk factors for nasopharyngeal cancer among female textile workers in Shanghai, China

AIMS

To investigate whether occupational exposure to dusts and chemicals in the Chinese textile industry are associated with risk of nasopharyngeal cancer.

METHODS

Sixty seven nasopharyngeal carcinoma (NPC) cases identified during 1989-98 and a random sample (n = 3188) of women were included in a case cohort study nested in a cohort of 267,400 women textile workers in Shanghai, China. A complete occupational history of work in the textile industry was obtained for each woman. A job exposure matrix developed by experienced industrial hygienists was used to assess exposures to specific dusts and chemicals.

RESULTS

Risk of NPC is associated with cumulative exposure to cotton dust. The hazard ratio for women cumulatively exposed to >143.4 mg/m3 x years of cotton dust was 3.6 (95% CI 1.8 to 7.2) compared with unexposed women. Trends of increasing risk were also found with increasing duration of exposure to acids and caustics (p = 0.05), and with years worked in dyeing processes (p = 0.06). Women who worked at least 10 years in dyeing processes had a 3.6-fold excess risk of NPC (95% CI 1.0 to 12.1).

CONCLUSIONS

Occupational exposure to cotton dust, acids, and caustics, and work in dyeing and printing jobs in the textile industry may have increased risk of NPC in this cohort.

Elevated lung cancer risk shortly after smoking cessation: is it due to a reduction of endotoxin exposure?

Several reports indicate that the risk of lung cancer increases slightly for a short period of time after cessation of smoking while the risk of adverse cardiovascular events drops immediately. Recent studies on subjects occupationally exposed to organic dust-containing endotoxin have revealed lower than expected rates of lung cancer. There is experimental evidence that stimulation of the immune system by endotoxin has a protective effect against cancer. Tobacco smoke has been shown to contain high levels of endotoxin. We therefore postulate that cessation of smoking eliminates the protective effect of endotoxin. Any benefit conferred by endotoxin does not, however, justify smoking. As the inverse relationship between exposure to endotoxin and the risk of lung cancer is a strong one, endotoxin-like substances could form the basis of vaccination strategies.

Lung cancer risk: effect of dairy farming and the consequence of removing that occupational exposure

The aim of this study was to confirm the exposure-dependent reduction in lung cancer risk reported for dairy farmers exposed to endotoxin and to evaluate the consequence of leaving dairy farming and taking employment in industry or services, where exposure to microbial agents is lower. Standardized mortality ratios, with 95% confidence intervals, for 2,561 self-employed dairy farmers were estimated, considering the general population of Veneto, Italy, from 1970 to 1998 as the reference. Sixty-two lung cancer cases, whose information was checked against clinical records, were compared with 333 controls in a cohort-nested case-control study. Odds ratios with 95% confidence intervals were estimated by logistic regression analysis. A downward trend of standardized mortality ratios for lung cancer across tertiles of number of dairy cattle on the farm was significant (p < 0.05) from 1970 to 1984 but not from 1985 to 1998, when most subjects were no longer dairy farmers. Age- and smoking-adjusted odds ratios for lung cancer significantly decreased with increasing number of dairy cattle (p for trend = 0.001) for workers for whom < or =15 but not >15 years had elapsed from the end of work to the end of follow-up. In conclusion, increased levels of endotoxin (or other associated environmental factors) might be protective against lung cancer; protection diminishes over time after that exposure is removed.