Organochlorine pesticides in carcinoma of the gallbladder: a case-control study

Gallbladder cancer: Progress in the Indian subcontinent

Gallbladder cancer (GBC) is one of the commonest biliary malignancies seen in India, Argentina, and Japan. The disease has dismal outcome as it is detected quite late due to nonspecific symptoms and signs. Early detection is the only way to improve the outcome. There have been several advances in basic as well as clinical research in the hepatobiliary and pancreatic diseases in the West and other developed countries but not enough has been done in GBC. Therefore, it is important and the responsibility of the countries with high burden of GBC to find solutions to the many unanswered questions like etiopathogenesis, early diagnosis, treatment, and prognostication. As India being one of the largest hubs for GBC in the world, it is important to know how the country has progressed on GBC. In this review, we will discuss the outcome of the publications from India highlighting the work and the developments taken place in past several decades both in basic and clinical research.

UIdataGB: Multi-Class ultrasound images dataset for gallbladder disease detection

Artificial Intelligence (AI) allows computers to self-develop decision-making algorithms through huge data analysis. In medical investigations, using computers to automatically diagnose diseases is a promising area of research that could change healthcare strategies worldwide. However, it can be challenging to reproduce or/and compare various approaches due to the often-limited datasets comprising medical images. Since there is no open access dataset for the Gallbladder (GB) organ, we introduce, in this study, a large dataset that includes 10,692 GB Ultrasound Images (UI) acquired at high resolution from 1,782 individuals. These UI include many disease types related to the GB, and they are organized around nine important anatomical landmarks. The data in this collection can be used to train machine learning (ML) and deep learning (DL) models for computer-aided detection of GB diseases. It can also help academics conduct comparative studies and test out novel techniques for analyzing UI to explore the medical domain of GB diseases. The objective is then to help move medical imaging forward so that patients get better treatment.

Risk factors associated with gall bladder cancer in high incidence areas in India: a systematic review protocol

INTRODUCTION

Gall bladder cancer (GBC) is a lethal form of malignancy of the gastrointestinal tract with a unique geographical distribution. Cases are aggregated in the river basins of Ganga-Brahmaputra, in the north, east and north-east India, collectively termed as the 'high-risk' zone for GBC. Although some studies report high prevalence of typhoid infection linking with high burden of GBC in these regions, there is no systematic review of the factors associated with GBC in the high incidence areas. To address this gap, we are conducting a systematic review to identify and organise the factors associated with GBC in the high-risk zone of India.

METHODS AND ANALYSIS

A systematic review of all observational studies that report a quantitative relationship between at least one risk factor for GBC among adults (>18 years) in the high-risk zone in India will be conducted. The databases PubMed-MEDLINE, CINAHL, EMBASE, Web of Science, Scopus, OpenGrey and Google Scholar published in English and after 1990 will be searched. This review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. The primary outcome is GBC. If data permit, meta-analysis will be performed. Two independent reviewers will independently screen the articles, extract the data and assess the methodological quality of the studies.

ETHICS AND DISSEMINATION

As this will be a systematic review without human participants' involvement, there will be no requirement for ethics approval. Findings will be disseminated widely through peer-reviewed publication and media, for example, conferences and symposia.

PROSPERO REGISTRATION NUMBER

CRD42021256673.

Assessment of the genotoxic potential of tetrachlorvinphos insecticide by cytokinesis-block micronucleus and sister chromatid exchange assays

Tetrachlorvinphos is an organophosphate that is classified as a carcinogen in humans by several authorities. Due to very limited data regarding the genotoxic potential, we aimed to comprehensively investigate in vitro genotoxic potential of tetrachlorvinphos. We performed our study by applying the cytokinesis-block micronucleus cytome and sister chromatid exchange (SCE) assays to human peripheral blood lymphocytes. We evaluated micronucleus (MN) and SCE frequencies and cytokinesis-block proliferation index in both exposed and non-exposed lymphocytes. We also calculated the chromosomal instability level in response to exposure by combining the results of MN and SCE. We found that MN frequency did not increase with exposure to tetrachlorvinphos (0-50 µg/ml). In contrast, we observed that SCE frequencies significantly increased with exposure to ≥5 µg/ml tetrachlorvinphos. Furthermore, exposure to tetrachlorvinphos at concentrations of 50 µg/ml induced a significant increase in chromosomal instability level (p < 0.05). Cytokinesis-block proliferation index level did not significantly decrease in response to tetrachlorvinphos exposure. Our findings reveal that tetrachlorvinphos resulted in different DNA damages that were measured by two assays. Furthermore, our findings suggested that exposure to tetrachlorvinphos increased chromosomal instability that is a hallmark of many malignancies. We conclude that although tetrachlorvinphos does not significantly increase the MN level, the significant increase of both SCE and CIN frequencies indicates the genotoxic potential of tetrachlorvinphos in human peripheral lymphocytes. Additionally, tetrachlorvinphos is not cytotoxic in the range of tested concentrations.

Carcinogen Metabolism Pathway and Tumor Suppressor Gene Polymorphisms and Gallbladder Cancer Risk in North Indians: A Hospital-Based Case-Control Study

Background:

Carcinogen metabolism pathway and tumor suppressor gene polymorphisms have been reported to be associated with increased gallbladder cancer risk. However, the association of genetic variants and gallbladder cancer risk in Indians are not well studied. We examined whether genetic polymorphisms of metabolic enzymes cytochrome P450 1A1 and glutathione S-transferase and tumor suppressor gene p53 (TP53) are associated with an increased risk of gallbladder cancer in North Indians.

Methods:

This hospital-based case-control study was conducted in 96 gallbladder cancer patients with gallstones (cases) and 93 cholelithiasis patients (controls) at the Sanjay Gandhi Postgraduate Institute of Medical Sciences in Lucknow, India from July 2014 through May 2017. Genomic DNA was extracted from white blood cells of each patient using a simple salting-out procedure. The genotypic frequencies of CYP1A1 rs4646903, CYP1A1 rs1048943, and TP53 rs1042522 polymorphisms were investigated using TaqMan SNP Genotyping Assay and GSTM1 and GSTT1 polymorphisms were analyzed using the multiplex PCR assay.

Results:

The frequency of CC genotype of TP53 rs1042522 polymorphism was 27.1% (26/96) in cases and 12.9% (12/93) in controls. The CC genotype was associated with an increased risk of gallbladder cancer in North Indians (age- and sex-adjusted odds ratio, 2.81; 95% confidence interval, 1.19–6.61; P = 0.02). No significant differences in genotypic and allelic frequencies of the metabolic pathway gene polymorphisms were found between cases and controls.

Conclusions:

Our data provide preliminary evidence that the CC genotype of the TP53 rs1042522 polymorphism may be associated with an increased risk of gallbladder cancer in North Indians.

Levels of organochlorine pesticides in Amazon turtle (Podocnemis unifilis) in the Xingu River, Brazil

Due to the toxicity and high environmental persistence of organochlorine pesticides in aquatic organisms, turtles have been studied as environment biomonitors. These animals are important sources of protein for the riverside and indigenous peoples of the Brazilian amazon. In the present study, organochlorine pesticide contamination was investigated in Podocnemis unifilis. Liver, muscle and fatty tissue samples were removed from 50 specimens collected from five sampling points located in the Xingu River basin. Fourteen organochlorine pesticides were analysed via gas chromatography with an electron capture detector (CG-ECD). Eight organochlorine pesticides were detected with average concentrations of ∑DDT, ∑Endossulfan and ∑HCH which were 26.17 ± 26.35, 14.38 ± 23.77 and 1.39 ± 8.46 ng g^-1 in moisture content, respectively. DDT compounds were the most predominant, with a greater concentration of pp'-DDT in the liver and pp'-DDD in the muscle. Significant differences were noted between the types of tissues studied, and the concentration of OCPs varied between sampling sites.

Toxicological profile of organochlorines aldrin and dieldrin: an Indian perspective

Several epidemiological studies have suggested various environmental factors as a possible cause for increased incidence of various abnormalities. Of the various environmental contaminants, the most prevalent and the most discussed are the endocrine disrupting chemicals. Contact of such disruptors with humans has become inevitable today. They are cosmopolitan and present from agriculture to industrial sectors, even in day-to-day consumer products. Aldrin and dieldrin belong to one such class of substances which are known to have a toxic effect on various physiological systems of the human body. Despite an imposed ban on their manufacture and commercial use, these pesticides could still be detected in probable areas of consumption like agriculture. The present review discusses the known possible toxic effects of aldrin and dieldrin and their current existence in the ecosystem across India.

Pesticides: an update of human exposure and toxicity

Pesticides are a family of compounds which have brought many benefits to mankind in the agricultural, industrial, and health areas, but their toxicities in both humans and animals have always been a concern. Regardless of acute poisonings which are common for some classes of pesticides like organophosphoruses, the association of chronic and sub-lethal exposure to pesticides with a prevalence of some persistent diseases is going to be a phenomenon to which global attention has been attracted. In this review, incidence of various malignant, neurodegenerative, respiratory, reproductive, developmental, and metabolic diseases in relation to different routes of human exposure to pesticides such as occupational, environmental, residential, parental, maternal, and paternal has been systematically criticized in different categories of pesticide toxicities like carcinogenicity, neurotoxicity, pulmonotoxicity, reproductive toxicity, developmental toxicity, and metabolic toxicity. A huge body of evidence exists on the possible role of pesticide exposures in the elevated incidence of human diseases such as cancers, Alzheimer, Parkinson, amyotrophic lateral sclerosis, asthma, bronchitis, infertility, birth defects, attention deficit hyperactivity disorder, autism, diabetes, and obesity. Most of the disorders are induced by insecticides and herbicides most notably organophosphorus, organochlorines, phenoxyacetic acids, and triazine compounds.

Assessment of the genotoxic effects of organophosphorus insecticides phorate and trichlorfon in human lymphocytes

In vitro genotoxic effects of organophosphorus insecticides Phorate (PHR) and Trichlorfon (TCF) were investigated using four genotoxicity endpoints. Different concentration ranges between 0.25-2.00 μg mL(-1) of PHR and 2.34-37.50 μg mL(-1) of TCF were applied to lymphocytes. PHR and TCF significantly increased the frequency of chromosomal aberrations (except 2.34 μg mL(-1) for TCF) and sister chromatid exchanges at all treatment times and concentrations. Most of the used concentrations induced a significant increase in the frequency of micronuclei. Furthermore, PHR and TCF significantly decreased the mitotic index at the higher concentrations after 24- and 48-h treatments. In the comet assay, PHR and TCF significantly increased the comet tail at all concentrations. However, the comet tail intensity was significantly increased at only the highest concentration of PHR and at all concentrations of TCF. According to these results, PHR and TCF possess clastogenic, mutagenic, and DNA damaging effects in human lymphocytes in vitro.

Aldrin and dieldrin: a reevaluation of the cancer and noncancer dose-response assessments

The dose-response analyses of cancer and noncancer health effects of aldrin and dieldrin were evaluated using current methodology, including benchmark dose analysis and the current U.S. Environmental Protection Agency (U.S. EPA) guidance on body weight scaling and uncertainty factors. A literature review was performed to determine the most appropriate adverse effect endpoints. Using current methodology and information, the estimated reference dose values were 0.0001 and 0.00008 mg/kg-day for aldrin and dieldrin, respectively. The estimated cancer slope factors for aldrin and dieldrin were 3.4 and 7.0 (mg/kg-day)(-1), respectively (i.e., about 5- and 2.3-fold lower risk than the 1987 U.S. EPA assessments). Because aldrin and dieldrin are no longer used as pesticides in the United States, they are presumed to be a low priority for additional review by the U.S. EPA. However, because they are persistent and still detected in environmental samples, quantitative risk assessments based on the best available methods are required. Recent epidemiologic studies do not demonstrate a causal association between aldrin and dieldrin and human cancer risk. The proposed reevaluations suggest that these two compounds pose a lower human health risk than currently reported by the U.S. EPA.

Simultaneous occurrence of gallbladder cancer in a laundry couple: association between gallbladder cancer and benzene

Gallbladder (GB) cancer occurs predominately as a biliary tract malignant tumor. It generally has a very poor prognosis, and early detection is often difficult. A variety of carcinogens have been implicated as an important cause for GB cancer. Benzene is a well-known carcinogen for hematologic malignancy, and its casual relationship with GB cancer has been suggested. We report a case of two patients who had operated a laundry cleaning facility together and later simultaneously got GB cancer after prolonged benzene exposure.

Role of nicotine in gallbladder carcinoma: a preliminary report

OBJECTIVE

To assess the role of nicotine in gallbladder carcinoma and its association with the stage and degree of cancer differentiation.

METHODS

Tissue samples from gallbladder were obtained from 20 patients with gallbladder cancer and 20 age- and gender-matched patients with cholelithiasis who served as the control group. Gallbladder tissue (2 g) was extracted and analyzed for nicotine content using capillary gas chromatography. Nitrogen was used as the carrier gas. Standard curves of nicotine in methanol were made by injecting the internal standards.

RESULTS

A significantly higher tissue nicotine concentration was observed in the gallbladder carcinoma group than that in the control group (179.63 ng/mg vs 6.00 ng/mg, P < 0.001). The stage and degree of cancer differentiation did not seem to affect the nicotine levels. Gallbladder tissue contained a significantly higher nicotine concentration in smokers with cancer compared with those in the control group (1570.00 ng/mg vs 232.25 ng/mg, P < 0.001). Interestingly, non-smokers in cancer group also had a higher nicotine concentration than the control group (161.50 ng/mg vs 4.00 ng/mg, P = 0.002).

CONCLUSION

Nicotine is selectively concentrated in malignant gallbladder tissue irrespective of smoking status, showing its strong association with gallbladder cancer.

Candidate gene studies in gallbladder cancer: a systematic review and meta-analysis

Gallbladder cancer (GBC) is the most frequent biliary tract malignancy. Wide variations in GBC incidence and familial and epidemiological data suggest involvement of a genetic component in its etiopathogenesis. A systematic review of genetic association studies in GBC was performed by applying a meta-analysis approach and systematically reviewing PubMed database using appropriate terms. Odds ratios (ORs) and 95% confidence intervals (CIs) were appropriately derived for each gene-disease association using fixed and random effect models. Meta-regression with population size and genotyping method was also performed. Study quality was assessed using a 10-point scoring system designed from published guidelines. Following a review of 44 published manuscripts and one unpublished report, 80 candidate gene variants and 173 polymorphisms were analyzed among 1046 cases and 2310 controls. Majority of studies were of intermediate quality. Four polymorphisms with >3 separate studies were included in the meta-analysis [OGG1 (rs1052133), TP53 (rs1042522), CYP1A1 (rs1048943) and GSTM1 null polymorphism]. The meta-analysis demonstrated no significant associations of any of the above polymorphisms with GBC susceptibility except TP53 (rs1042522) polymorphism. To conclude, existing candidate gene studies in GBC susceptibility have so far been insufficient to confirm any association. Future research should focus on a more comprehensive approach utilizing potential gene-gene, gene-environment interactions and high-risk haplotypes.

DNA damage and cholinesterase activity in occupational workers exposed to pesticides

The present study was designed to evaluate genotoxicity, acetyl cholinesterase (AChE) activity, hepatic and renal toxicity in occupational workers exposed to mixture of pesticides (n=70) with same number of healthy subjects as controls. The mean comet tail DNA % (TD %) and tail moment (TM) were used to measure DNA damage, while AChE activity and other biochemical parameters such as markers of nephrotoxicity (urea and creatinine) and hepatotoxicity (AST, ALT and ALP) were measured as biomarkers for toxicity due to exposure of pesticides. The occupational workers were continuously exposed to mixture of pirimiphos methyl, chlorpyrifos, temephos and malathion on a regular interval as per usage and activity. The comet assay using lymphocytes of exposed workers showed significantly higher TD percentage value (60.43% vs. 31.86%, p<0.001) and TM value (14.48 μm vs. 6.42 μm, p<0.001) in occupational workers as compared to controls. AChE activity in erythrocytes was found to be decreased (3.45 KAU/L vs. 9.55 KAU/L in controls, p<0.001) and associated with the duration of exposure to pesticides used by the workers. Enzyme levels for hepatic and renal functions were also found significantly different in occupational workers than healthy controls (p<0.001). These results suggest that the exposure to mixture of pirimiphos methyl, chlorpyrifos, temephos and malathion may induce DNA damage, decrease in AChE activity, hepatotoxicity as well as nephrotoxicity. Periodic biomonitoring of these biomarkers along with imparting education and training to occupational workers for safe application of pesticides is recommended for its potential hazards.

Occupational exposure to pesticides and bile tract carcinoma in men: results from a European multicenter case-control study

OBJECTIVES

To estimate the associations between occupational exposure to pesticides and extrahepatic biliary tract carcinoma in men, a population-based case-control study was carried out.

METHODS

Cases (n = 104), aged 35-70, diagnosed in 1995-1997, were sampled by active reporting systems from hospitals. Controls (n = 1,401) were a random sample of the general male population. Information on occupation and confounding factors was obtained by questionnaires. Exposures were quantified with respect to time, application methods, and use of personal protective equipment. Intensity was evaluated by using a published algorithm which weighted the exposure assigned according to the use of personal protective equipment and mode of application. Logistic regression analyses were conducted adjusted for gallstones, age, and country.

RESULTS

Being ever exposed to pesticides resulted in an odds ratio (OR) of 1.0 [95%-confidence interval (CI) 0.6-1.6]. A modestly elevated risk was found for backpack mounted sprayers OR = 1.4 [95% CI 0.7-2.6] and vine farmers OR = 2.5 [95% CI 0.9-7.2]. Using time periods and exposure frequency as intensity measure, no elevated risks were found. The only exception was year of maximum exposure which yielded an OR of 1.6 [95% CI 0.7-3.5]. However, no clear trend was observed in this analysis.

CONCLUSIONS

This study does not rule out that pesticide exposure represents an occupational risk factor for extrahepatic biliary tract carcinoma, but no indication of a strong association was observed. Some modes of exposure were weakly, albeit not significantly associated with carcinoma risk. The observed estimates of effects may be influenced by a lack of precise exposure assessment. Different chemical compositions of pesticides were utilized during a long time span of pesticide exposure, and it should be considered that the exposure is assessed with substantial uncertainty that could non-differential and bias results toward the null.

DNA damage in Pakistani agricultural workers exposed to mixture of pesticides

A cross-sectional study was designed to determine whether occupational exposure to a complex mixture of pesticides results in a significant increase of DNA damage in farmers chronically exposed to pesticides in open fields. Leukocytes from 47 agriculture workers exposed to pesticides and 50 controls were evaluated with comet assay. Workers recruitment was based on their exposure to pesticides during the spraying season on cotton crop. Serum from these individuals was also analyzed for pesticides presence using high performance liquid chromatography. Statistically significant difference (P < 0.001) in DNA damage of exposed individuals (mean +/- S.D 14.80 +/- 3.04 microm) was observed when compared with control group (6.54 +/- 1.73 microm) as studied on the basis of comet tail length. Smokers had significantly higher mean comet tail length than nonsmokers and ex-smokers in both workers (20.26 +/- 3.53 vs. 14.19 +/- 4.25, P < 0.001) and controls (7.86 +/- 1.09 vs. 5.80 +/- 1.59, P < 0.001), whereas age had a minimal effect on DNA damage (P < 0.05). The length of pesticide exposure is positively associated with DNA damage in exposed individuals (P < 0.001). Our study shows that chronic exposure to pesticides produces DNA damage in pesticide sprayers and suggests that this type of monitoring is recommended in preventive policies for pesticide sprayers.

Evaluation of genetic damage in a Brazilian population occupationally exposed to pesticides and its correlation with polymorphisms in metabolizing genes

Cytogenetic damage in individuals occupationally exposed to pesticides has received the attention of investigators in several countries, but no definitive conclusions can yet be made. The present study aimed at assessing if prolonged exposure to complex mixtures of pesticides leads to an increase in cytogenetic damage. Vineyard workers exposed to pesticides in Caxias do Sul (Brazil) were evaluated using the micronucleus (MN) test in binucleated lymphocytes and the comet assay in peripheral leukocytes. In order to evaluate if genetically determined individual variations in xenobiotic metabolizing capacity could modify individual susceptibility to the possible genotoxic effects of pesticides, the subjects were genotyped for several genes: GSTT1, GSTM1, GSTP1, CYP1A1, CYP2E1 and PON. The study involved a total number of 173 men: 108 were agricultural workers exposed to pesticides and 65 were controls. The present study showed a high rate of MN and DNA damage in pesticide-exposed individuals (P <or= 0.001; Mann-Whitney U-test). In addition, some effects of genetic polymorphisms in PON in the modulation of MN results were observed in the exposed group, and an association between GSTM1, GSTT1 and CYP2E1 polymorphisms was suggested.

Genotoxic biomonitoring study of population residing in pesticide contaminated regions in Göksu Delta: micronucleus, chromosomal aberrations and sister chromatid exchanges

Pesticides are widely used throughout the world in agriculture to protect crops and in public health to control diseases. Nevertheless, exposure to pesticides represents a potential risk to humans. This paper describes a study of possible genetic damage in the people living in regions contaminated with complex mixture of pesticides in Göksu Delta. In this study, used methods were chromosomal aberration (CA), sister chromatid exchange analysis (SCE) in the peripheral blood lymphocytes, and micronucleus (MN) assay in the buccal epithelial cells. In the present investigation, 32 affected subjects consist of 16 smoking and 16 non-smokings and an equal number of control subjects were assessed for genome damage. Micronucleus (MN), Broken egg (BE), Karyorrhexis (KR), Karyolysis (KL) and Binucleus (BN) frequencies were higher in affected subjects than in controls. Smoking had a statistically significant effect on the Micronucleus, Karyorrhexis and Binucleus frequencies for both the control and the exposed group. Also smoking and exposure affected the frequency of sister chromatid exchange and chromosomal aberrations compared with control groups.

Advanced gallbladder cancer: Indian “middle path”

Gallbladder cancer (GBC) is common in northern India. The western world has a pessimistic attitude towards GBC resulting in inadequate management of even early GBC. At the other extreme is the Japanese aggressivism with high mortality but very few actual long-term survivors. The Indian surgeons have adopted a Buddhist "middle path"--aggressive surgical approach for "less advanced" GBC and non-surgical palliative approach for "more advanced" GBC. We rely heavily on staging laparoscopy to detect metastatic deposits on liver, peritoneum and omentum, and upper gastrointestinal endoscopy (UGIE) to detect duodenal infiltration which indicates unresectability as we do not perform pancreatico-duodenectomy for GBC. Our favoured procedure is extended cholecystectomy (EC) which includes a 2 cm nonanatomical wedge of liver in the GB bed and the lymph nodes in hepatoduodenal ligament, behind the duodenum and head of pancreas and along the hepatic artery to the right of celiac axis. EC can achieve R0 resection in patients with T1-T2 and T3 (fundus/body--hepatic bed type) disease. For T3 (neck--hepatic hilum type) and T4 disease major hepatic resection is required. In selected patients with nodally advanced GBC, a non-curative simple cholecystectomy with post-operative chemoradiotherapy may improve survival. GBC is an "Indian disease" and Indian surgeons have to be prepared to accept the "challenge" of GBC.

Polymorphisms of cytochrome P450 1A1, glutathione S-transferase class mu, and tumour protein p53 genes and the risk of developing gallbladder cancer in Japanese

OBJECTIVES

To examine the relationship between genetic polymorphisms of cytochrome P450 1A1 (CYP1A1), glutathione S-transferase class mu (GSTM1), and tumour protein p53 (TP53) genes, and gallbladder cancer (GBC) risk, a case-control study was conducted.

DESIGN AND METHODS

Genotypes of CYP1A1 T3801C, CYP1A1 Ile462Val, GSTM1, and TP53 Arg72Pro were determined in 54 cases of GBC and 178 controls.

RESULTS

The age-adjusted odds ratios (ORs) for the Ile/Val genotype of CYP1A1 Ile462Val polymorphism in women and the Arg/Pro genotype of TP53 Arg72Pro polymorphism in men were observed to be 2.70 (95% CI: 1.14-6.40) and 4.32 (95% CI: 1.08-17.2), respectively. No significant differences in the genotypic frequencies of CYP1A1 T3801C and GSTM1 polymorphisms were observed between controls and cases in both men and women.

CONCLUSION

These results suggest that the Val allele of CYP1A1 Ile462Val polymorphism and the Pro allele of TP53 Arg72Pro polymorphism contribute to an increased risk of GBC among Japanese women and men, respectively.

Risks of biliary tract cancer and occupational exposures among Shanghai women textile workers: a case-cohort study

BACKGROUND

Biliary tract cancer (BTC) is a relatively rare malignancy worldwide. Little is known about potential etiologic contributions of occupational exposures.

METHODS

The associations between occupational exposures to textile dusts and chemicals and BTC are investigated in a cohort of 267,400 women textile workers in Shanghai, China. A nested case-cohort analysis of 162 BTC cases diagnosed during 1989-1998 was conducted with a reference subcohort of 3,188 workers. Exposures to workplace dusts and chemicals were reconstructed by linking complete work history data with a job-exposure matrix (JEM). Hazard ratios (HR) and dose-response trends were estimated by Cox proportional hazards modeling modified for case-cohort design.

RESULTS

An elevated risk of > or = 1-year employment in maintenance jobs (HR 2.92, 95% CI: 1.48, 5.73) with a significant trend by duration is observed. Excess risk was also found for > or = 20 years exposure to metals (HR 2.50, 95% CI: 1.09, 5.72).

CONCLUSIONS

Long-term exposure to maintenance work and metals in the textile industry may have increased BTC risk in this population.

Geographic pathology revisited: development of an atlas of cancer in India

Information on 217,174 microscopically diagnosed cancers diagnosed in 2001-2002 was collected from pathology laboratories in 68 districts across India. Data collection took place primarily via the Internet. Average annual age-adjusted incidence rates for microscopically diagnosed cases (MAAR) by gender and site were calculated for each of the 593 districts in the country. The rates were compared to those from established population based cancer registries (PBCR). In 82 districts, the MAAR for 'all cancer sites' was above a "completeness" threshold of 36.2/100,000 (based on results of a rural PBCR). The results confirmed some known features of the geography of cancer in India, and brought to light new ones. Cancers of the mouth and tongue are particularly frequent in both genders in the southern states. Very high rates of nasopharynx cancer were found in the northeastern states (Nagaland, Manipur). There was clear geographic correlation between the rates of cervical and penile cancer, and a high rate of stomach and lung cancer (in both genders) in many districts of Mizoram State. The area of high risk for gallbladder cancer seems larger than suspected previously, involving a wide band of northern India. There is a belt of high incidence of thyroid cancer in females in southwest coastal districts. Other than identifying possible existence of high-risk areas of specific cancers, our study has recognized places where PBCR could be established. The study was remarkably cost-effective and the electronic data-capture methodology provides a model for health informatics in the setting of a developing country.