Cancer incidence in textile manufacturing workers in Australia

Cotton dust exposure and risk of lung cancer: A meta-analysis of observational studies

Findings on the association between cotton dust exposure and lung cancer risk in epidemiologic studies have been inconsistent. Therefore, we conducted a meta-analysis of data from observational studies to quantify this association.PubMed, EMBASE, and the Cochrane library databases were searched for observational studies with data on cotton dust exposure and lung cancer risk. Studies that reported adjusted relative risks (RRs) with 95% confidence intervals (CIs) of lung cancer associated with cotton dust exposure were included. Subgroup analyses were conducted according to key characteristics.Fifteen studies involving a total of 73,812 individuals were included in the meta-analysis. Combining estimates from all the 15 observational studies, cotton dust exposure was associated with a decreased risk of lung cancer (combined RR, 0.78; 95% CI, 0.66-0.91; P = .002). Pooled estimates of multivariate RRs by gender were 0.71 (95% CI, 0.58-0.88; P = .001) among males, based on 7 studies, and 0.77 (95% CI, 0.67-0.89; P < .001) among females, based on 9 studies. Further analyses examining the influence of a single study on the results by omitting a study at each turn yielded a range of RR from 0.74 to 0.82.Our meta-analysis indicates that cotton dust exposure is associated with a decreased risk of lung cancer.

Lack of a protective effect of cotton dust on risk of lung cancer: evidence from two population-based case-control studies

BACKGROUND

Lung cancer is the leading cause of cancer death in North America. Exposure to cotton dust has previously been reported to decrease the risk of lung cancer.

METHODS

We used data from two large case-control studies conducted in Montreal from 1979-1986 (Study 1) and 1996-2002 (Study 2) respectively, to examine the association between occupational exposure to cotton dust and risk of lung cancer. Cases were diagnosed with incident histologically-confirmed lung cancer (857 in Study 1, 1203 in Study 2). Population controls were randomly selected from electoral lists and frequency-matched to cases by age and sex (533 in Study 1, 1513 in Study 2). Interviews for the two studies used a virtually identical questionnaire to obtain lifetime occupational and smoking history, and several lifestyle covariates. Each participant's lifetime occupational history was reviewed by experts to assess exposure to a number of occupational agents, including cotton dust. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by unconditional logistic regression, adjusting for potential confounders.

RESULTS

The lifetime prevalence of exposure to cotton dust was approximately 10%-15% in both studies combined, with some variation by study and by sex. Overall there was no decreased risk of lung cancer among subjects exposed to cotton dust. Rather, among all subjects there was a suggestion of slightly increased risk associated with any lifetime exposure to cotton dust (OR = 1.2, 95% CI: 1.0-1.5). This risk appeared to be concentrated among cases of adenocarcinoma (OR = 1.6, 95% CI: 1.2-2.2), and among moderate and heavy smokers (OR = 1.3, 95% CI: 1.0-1.7). There was no association when restricting to cases of either squamous cell or small cell cancer, or among never smokers and light smokers. An analogous examination of subjects exposed to wool dust revealed neither increased nor decreased risks of lung cancer.

CONCLUSIONS

There was no evidence that cotton dust exposure decreased risks of lung cancer.

Occupational exposure and thoracic malignancies, is there a relationship?

OBJECTIVES

The aim of this study was to evaluate the effect of occupational exposure in the occurrence of lung cancer.

METHOD

Three-hundred lung cancer cases diagnosed between September 1, 1999, and September 31, 2007, and 300 healthy controls were enrolled in this case-control study. Life-long occupational history, gender, age, exposure to asbestos, comorbidities, and smoking status were collected.

RESULTS

The mean age of the 300 lung cancer cases was 60.3 ± 9.9 year (91.7% male and 8.3% female), and the mean age of healthy control group was 60.4 ± 10.5 year (95.0% male and 5.0% female). The most frequent histological types were squamous (172, 57.3%), adeno (69, 23.1%), and small cell (37, 12.3%). There was an increased risk of lung cancer occurrence among agriculture workers (OR=1.89, 95% Cl=1.17-2.98) (p=0.009). Inorganic dust exposure (OR=1.81, 95% Cl=1.0-3.25) (p=0.049) and organic dust exposure (OR=1.89, 95% Cl=1.0-3.59) (p=0.05) were found to be related with high frequency of having lung cancer.

CONCLUSION

Workers who had occupational exposure to organic and inorganic dust, especially in the agricultural field, had higher risk of lung cancer occurrence when compared with office workers.

Lung cancer mortality in a cohort of UK cotton workers: an extended follow-up

Background:

A recent systematic review and meta-analysis suggested that occupational exposure to endotoxins protects against lung cancer. To explore this hypothesis further, the follow-up of mortality of a cohort of 3551 workers, who were employed in the British cotton industry during 1966–1971, was extended by 23 years.

Methods:

Subjects had originally been recruited to a survey of respiratory disease, which collected information about occupation and smoking habits. Cumulative exposures to endotoxins were estimated from data on endotoxin levels by work areas in cotton mills. Risks of lung cancer were estimated using survival modelling.

Results:

During follow-up, 2018 deaths were recorded before the age of 90 years, including 128 deaths from lung cancer. After adjustment for smoking, hazard ratios (95% confidence intervals) for cumulative endotoxin exposures of ⩽30 000, >30 000 and ⩽200 000, >200 000 and ⩽400 000, >400 000 and ⩽600 000 and >600 000 endotoxin units (EU) m⁻³ years were 1, 0.8 (0.5–1.6), 0.7 (0.4–1.3), 0.6 (0.3–1.0) and 0.5 (0.3–0.9), respectively (P for trend=0.005).

Conclusion:

Our findings strengthen the evidence that occupational exposure to endotoxins protects against lung cancer, and suggest that the effect depends on cumulative dose and persists after exposure ceases.

Endotoxin exposure and lung cancer risk: a systematic review and meta-analysis of the published literature on agriculture and cotton textile workers

Objective

To examine the association between exposure to endotoxins and lung cancer risk by conducting a systematic review and meta-analysis of epidemiologic studies of workers in the cotton textile and agricultural industries; industries known for high exposure levels of endotoxins.

Methods

Risk estimates were extracted from studies published before 2009 that met predefined quality criteria, including 8 cohort, 1 case–cohort, and 2 case–control studies of cotton textile industry workers, and 15 cohort and 2 case–control studies of agricultural workers. Summary risk estimates were calculated using random effects meta-analyses. Potential sources of heterogeneity were explored through subgroup analyses.

Results

The summary risk of lung cancer was 0.72 (95% CI, 0.57–0.90) for textile workers and 0.62 (0.52–0.75) for agricultural workers. The relative risk of lung cancer was below 1.0 for most subgroups defined according to sex, study design, outcome, smoking adjustment, and geographic area. Two studies provided quantitative estimates of endotoxin exposure and both studies tended to support a dose–dependent protective effect of endotoxins on lung cancer risk.

Conclusion

Despite several limitations, this meta-analysis based on high-quality studies adds weight to the hypothesis that occupational exposure to endotoxin in cotton textile production and agriculture is protective against lung cancer.

Cancer mortality among textile workers in Shanghai, China: a preliminary study

OBJECTIVE

We assessed the association between cotton textile work and cancer mortality.

METHODS

The cancer mortality experience of 912 (444 cotton, 468 silk) textile workers in Shanghai, China, was compared. Workers were followed from 1981 to 2003. The associations between cotton textile work and death due to all cancers combined (with and without lung cancer) and to gastrointestinal cancers were estimated with Cox models, adjusting for age, work years, and pack-years.

RESULTS

There were 69 deaths. The adjusted hazard rate ratio (HR) was 2.10 (95% confidence interval [CI], 0.98-4.47) for all cancers combined and 2.56 (95% CI, 1.14-5.74) after excluding lung cancer. For gastrointestinal cancers, the adjusted HR was 2.09 (95% CI, 0.83-5.27).

CONCLUSIONS

These preliminary data suggest that, with the exception of lung cancer, cotton workers have significantly higher cancer mortality rates than silk workers.