Occupation, smoking, opium, and bladder cancer: A case-control study

Bladder cancer risk in relation to occupations held in a nationwide case-control study in Iran

Globally, bladder cancer has been identified as one of the most frequent occupational cancers, but our understanding of occupational bladder cancer risk in Iran is less advanced. This study aimed to assess the risk of bladder cancer in relation to occupation in Iran. We used the IROPICAN case-control study data including 717 incident cases and 3477 controls. We assessed the risk of bladder cancer in relation to ever working in major groups of the International Standard Classification of Occupations (ISCO-68) while controlling for cigarette smoking, opium consumption. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI). In men, decreased ORs for bladder cancer were observed in administrative and managerial workers (OR 0.4; CI: 0.2, 0.9), and clerks (OR 0.6; CI: 0.4, 0.9). Elevated ORs were observed in metal processors (OR 5.4; CI: 1.3, 23.4), and workers in occupations with likely exposure to aromatic amines (OR 2.2; CI: 1.2, 4.0). There was no evidence of interactions between working in aromatic amines-exposed occupations and tobacco smoking or opium use. Elevated risk of bladder cancer in men in metal processors and workers likely exposed to aromatic amines aligns with associations observed outside Iran. Other previously confirmed associations between high-risk occupations and bladder cancer were not observed, possibly due to small numbers or lack of details on exposure. Future epidemiological studies in Iran would benefit from the development of exposure assessment tools such as job exposure matrices, generally applicable for retrospective exposure assessment in epidemiological studies.

The carcinogenicity of opium consumption: a systematic review and meta-analysis

The carcinogenicity of opium consumption was recently evaluated by a Working Group convened by the International Agency for Research on Cancer (IARC). We supplement the recent IARC evaluation by conducting an extended systematic review as well as a quantitative meta-analytic assessment of the role of opium consumption and risk for selected cancers, evaluating in detail various aspects of study quality on meta-analytic findings. We searched the published literature to identify all relevant studies on opium consumption and risk of selected cancers in humans through 31 October, 2022. Meta-relative risks (mRRs) and associated 95% confidence intervals (CIs) were estimated using random-effects models for studies of cancer of the urinary bladder, larynx, lung, oesophagus, pancreas, and stomach. Heterogeneity among studies was assessed using the I2 statistic. We assessed study quality and conducted sensitivity analyses to evaluate the impact of potential reverse causation, protopathic bias, selection bias, information bias, and confounding. In total, 2 prospective cohort studies and 33 case-control studies were included. The overall pooled mRR estimated for 'ever or regular' versus 'never' use of opium ranged from 1.50 (95% CI 1.13-1.99, I2 = 0%, 6 studies) for oesophageal cancer to 7.97 (95% CI 4.79-13.3, I2 = 62%, 7 studies) for laryngeal cancer. Analyses of cumulative opium exposure suggested greater risk of cancer associated with higher opium consumption. Findings were robust in sensitivity analyses excluding studies prone to potential methodological sources of biases and confounding. Findings support an adverse association between opium consumption and cancers of the urinary bladder, larynx, lung, oesophagus, pancreas and stomach.

Temporal Trends and Projections of Bladder Cancer Burden in China from 1990 to 2030: Findings from the Global Burden of Disease Study

PURPOSE

Identifying disease burden and risk factors of bladder cancer and projecting its epidemiological trend in China, which can provide reference data to formulate measures for its management and prevention.

METHODS

We analyzed the incidence, mortality, and disability-adjusted life-years (DALYs) data of bladder cancer in China from 1990 to 2019 and predicted to 2030 based on the Global Burden of Disease Study 2019. We also estimated the proportion of risk factors contributing to bladder cancer DALYs. The average annual percentage change (AAPC) in both sexes was calculated to quantify the temporal trends.

RESULTS

In China, the age-standardized incidence rate of bladder cancer increased from 3.3/100,000 in 1990 to 5.16/100,000 in 2019 (AAPC of 1.47), while the age-standardized mortality rate and age-standardized DALYs rate declined slightly (AAPC of -0.58 and -0.65, respectively). The burden of bladder cancer increased with age, which reached a peak over 85 years old. The main risk factor for bladder cancer was smoking, and the contribution of high fasting plasma glucose increased from 1990 to 2019, with an AAPC of 0.85 in males and 0.61 in females. We predicted total incident cases, deaths and DALYs will increase to 150,372 and 53,520 and 1043,688 in 2030, respectively. The disease burden of bladder cancer in males will consistently higher than that in females from 2020 to 2030.

CONCLUSION

Although mortality and DALYs rates showed downward trends, the disease burden remained heavy in China at present. More effective and long-term health policies are needed to develop for early prevention and treatment of bladder cancer.

Opium use and risk of bladder cancer: a multi-centre case-referent study in Iran

BACKGROUND

Bladder cancer (BC) is the 10th most common type of cancer worldwide and the fourth most common type of cancer in Iran. Opium use is considered as one of the risk factors for BC. We aim to assess the association between various parameters of opium use, which in Iran is mainly ingested or smoked in various forms, and the risk of BC.

METHOD

In this multi-centre case-referent study in Iran, 717 BC cases and 3477 referents were recruited to the study from May 2017 until July 2020. Detailed histories of opium use (duration, amount, frequency) and potential confounders were collected by trained interviewers. Multivariable unconditional logistic regression models were used to measure adjusted odds ratio (OR) and 95% confidence intervals (CI). The ORs were adjusted for age, gender, place of residence and pack-years of cigarette smoking.

RESULTS

Regular opium consumption was associated with an increased risk of BC (OR 3.5, 95% CI: 2.8, 4.3) compared with subjects who never used opium. Compared with continuous users, the risk decreased to one-third for those who stopped opium more than 10 years ago. The adjusted OR for those who used both crude opium (teriak) and opium juice was 7.4 (95% CI: 4.1, 13.3). There was a joint effect of opium and tobacco (OR for users of both opium and tobacco 7.7, 95% CI: 6.0, 9.7).

CONCLUSIONS

Regular opium use is associated with an approximately 4-fold risk for BC. The OR decreases along with the increasing time since stopping opium use.

Opium Use and Cancer Risk: A Comprehensive Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

Epidemiological studies have reported inconsistent associations between opium use and cancer risk. We therefore conducted a systematic review and meta-analysis to investigate the relationship between opium use and cancer risk.

METHODS

We searched PubMed, Scopus, ISI Web of Knowledge, and Google Scholar until February 2021 and references of retrieved relevant articles for observational studies that reported the risk of cancer in relation to opium use. Random-effects models were used to calculate pooled effect sizes (ESs) as well as 95% confidence intervals (CIs) for the association between opium use and cancer risk by considering opium doses and types, duration of consumption, and routes of opium use.

RESULTS

In total, 21 observational articles, with a total sample size of 64,412 individuals and 6,658 cases of cancer, were included in this systematic review and meta-analysis. Ever opium users, compared with never opium users, had 3.53 times greater risk of overall cancer (pooled ES: 3.53, 95% CI: 2.60-4.79, P ≤ 0.01). This positive association was also seen for some individual types of cancers except for esophageal and colon cancers. Also, we found that higher opium doses and higher duration of consumption were associated with an increased risk of overall and individual types of cancer. However, the associations between opium doses and the risk of head and neck and larynx cancers were not significant. In terms of the routes of opium use, both opium ingestion and smoking were positively associated with the risk of cancer. Regarding opium types, we found that using teriak, but not shireh, could increase the risk of cancer.

CONCLUSIONS

Our findings showed that opium use, particularly in the form of teriak, is a risk factor for cancer.

Occupational Exposure to Carcinogens and Occupational Epidemiological Cancer Studies in Iran: A Review

INTRODUCTION

The extent of exposure to occupational carcinogens is not well characterized in Iran, and little is known about the burden of occupational cancer.

OBJECTIVES

This study aimed to describe exposure to occupational carcinogens and occupational epidemiology studies in Iran.

METHODS

Relevant studies up to January 2021 in Iran were identified through three databases (PubMed, Web of Science, and Google Scholar).

RESULTS

Forty-nine publications from 2009 to 2020 (one cohort, 11 case-control, 34 exposure monitoring studies, and three cancer burden studies) were included. The exposure monitoring studies were conducted mainly in the petroleum industry, metal industry, manufacturing of electronics, manufacturing of plastics, construction industry, and service industry. A few of the case-control studies also reported increased risk of cancers in relation to work in those industries.

CONCLUSIONS

Occupational cancer epidemiology in Iran is at an early stage. Both epidemiological and exposure monitoring studies are generally limited in size to provide robust evidence of occupational cancer risks. A coherent strategy to estimate the occupational cancer burden in Iran should start with conducting epidemiological studies along with systematic monitoring of occupational carcinogens for use in hazard control and research.

Opium as a carcinogen: A systematic review and meta-analysis

BACKGROUND

Opium and its pyrolysates have been investigated as potential carcinogenic material through several studies in different body systems; however, the results were controversial and no consensus was achieved with this regard. Thus, we aimed to systematically review and meta-analyze all existed evidence regarding association between opium consumption and cancer.

METHODS

Four major electronic databases including ISI Web of Science, PubMed, Scopus, and Embase along with Magiran and SID were searched thoroughly for all published articles from inception up to September 25, 2020. All studies were appraised critically by Newcastle Ottawa Scale (NOS) checklist. Relevant demographic data and the intended results of the selected studies were extracted and their Odds ratios (OR) were pooled using Comprehensive Meta-analysis (CMA). The cumulative risk of opium for developing different cancers was calculated.

FINDINGS

34 studies comprised of 18,230 individuals were entered in our systematic review and finally 32 publications were enrolled in meta-analysis. Overall, using the random effects model, opium consumption was associated with increased rate of malignancies in both minimally[OR = 4.14 95%CI = (3.32-5.15)] and fully adjusted [OR = 4.35 95%CI = (3.36-5.62)] analyses. Moreover, using random effects fully adjusted model, the subgroup analysis revealed increased risk for larynx [OR = 9.58 95%CI = (6.31-14.53)], respiratory [OR = 9.02 95%CI = (6.27-12.96)], head and neck [OR = 8•03 95%CI = (4.03-16.00)], and colon [OR=5.58 95%CI = (3.14-9.92)] cancers for opium consumers compared to non-consumers.

INTERPRETATION

Opium consumption is highly associated with all reported types of cancers, especially in fully adjusted model; however, basic pathophysiology should be further investigated.

FUNDING

None.

Bladder Cancer in Iran: An Epidemiological Review

PURPOSE

Bladder cancer is the sixth most common cancer in Iran. Information about the epidemiological situation of the disease and its risk factors is necessary for conducting a planning program to reduce the disease. This study is conducted with the aim of evaluating the epidemiological features of bladder cancer in Iran.

METHODS

This is a systematic review of the published articles in both Persian and English in international and national journals during the years 2000-2019 with key words of Iran and bladder cancer. Articles were selected from the national information database (SID, Magiran) and international databases (PubMed, Scopus, and Web of Science). Articles related to the epidemiological aspects of the disease, including incidence, prevalence, mortality, and risk factors, were evaluated.

RESULTS

The incidence rate of bladder cancer was about 1.6-115; cumulative survival rate was 0.95, mortality rate was 0.5-0.84 and its prevalence in the Iranian population was between 4.10% and 12.8%. The risk of developing malignancy in major risk factor groups, including smoking and opium, was 6.2 (2.04-18.7), increases in protein and animal fat consumption were about 5- and 19-times higher than in the general population, respectively. In terms of occupational exposure, bus and heavy truck drivers were 11.3 (1.3-92.05) more at risk than others.

CONCLUSION

Regarding the increasing trend of this disease, changes in lifestyle to reduce risk factors can be effective in decreasing the incidence and mortality rate of this malignancy.

Review of refractory ceramic fiber (RCF) toxicity, epidemiology and occupational exposure

This literature review on refractory ceramic fibers (RCF) summarizes relevant information on manufacturing, processing, applications, occupational exposure, toxicology and epidemiology studies. Rodent toxicology studies conducted in the 1980s showed that RCF caused fibrosis, lung cancer and mesothelioma. Interpretation of these studies was difficult for various reasons (e.g. overload in chronic inhalation bioassays), but spurred the development of a comprehensive product stewardship program under EPA and later OSHA oversight. Epidemiology studies (both morbidity and mortality) were undertaken to learn more about possible health effects resulting from occupational exposure. No chronic animal bioassay studies on RCF have been conducted since the 1980s. The results of the ongoing epidemiology studies confirm that occupational exposure to RCF is associated with the development of pleural plaques and minor decrements in lung function, but no interstitial fibrosis or incremental lung cancer. Evidence supporting a finding that urinary tumors are associated with RCF exposure remains, but is weaker. One reported, but unconfirmed, mesothelioma was found in an individual with prior occupational asbestos exposure. An elevated SMR for leukemia was found, but was absent in the highly exposed group and has not been observed in studies of other mineral fibers. The industry will continue the product stewardship program including the mortality study.

The awareness of patients with non - muscle invasive bladder cancer regarding the importance of smoking cessation and their access to smoking cessation programs

Objectives

Smoking is the most important risk factor for bladder cancer and smoking cessation is associated with reduced risk of tumor recurrence and progression. The aim of this study is to assess the awareness of non-muscle invasive bladder cancer (NMIBC) patients regarding the importance of smoking cessation, determine their access to smoking cessation programs and the effects of smoking cessation on recurrence rates of NMIBC.

Materials and Methods

NMIBC patients who were followed with cystoscopy were included in the study. Their demographic properties were recorded, along with their smoking habits, awareness regarding the effects of smoking on bladder cancer and previous attempts for smoking cessation. Moreover, the patients were asked whether they applied for a smoking cessation program. Recurrence of bladder cancer during the follow-up period was also noted.

Results

A total of 187 patients were included in the study. The mean age was 64.68±12.05 (range: 15-90) and the male to female ratio was 167/20. At the time of diagnosis, 114 patients (61.0%) were active smokers, 35 patients (18.7%) were ex-smokers and 38 patients (20.3%) had never smoked before. After the diagnosis, 83.3% of the actively smoking patients were advised to quit smoking and 57.9% of them quit smoking. At the time of the study, 46.52% of the NMIBC patients were aware of the link between smoking and bladder cancer, whereas only 4.1% of the smoking patients were referred to smoking cessation programs. After a mean follow-up of 32.28±11.42 months, 84 patients (44.91%) had recurrence; however, current smoking status or awareness of the causative role of smoking on NMIBC did not affect the recurrence.

Conclusion

In our study group, the majority of the NMIBC patients were not aware of the association between smoking and bladder cancer. Although most of the physicians advised patients to quit smoking, a significant amount of the patients were still active smokers during follow-up. Only a small proportion of patients were referred to smoking cessation programs. Urologists should take a more active role in the battle against smoking and refer those patients to smoking cessation programs. Larger study populations with longer follow-up periods are needed to better demonstrate the beneficial effects of smoking cessation on recurrence rates.

Opium and bladder cancer: A systematic review and meta-analysis of the odds ratios for opium use and the risk of bladder cancer

Objective

The association between opium use and bladder cancer has been investigated in many studies, with varying reporting results reported. This study aims to estimate the total odds ratio for the association between bladder cancer and opium consumption using meta-analysis.

Methods

The study was designed according to PRISMA guidelines. Two independent researchers searched for the relevant studies using PubMed, Web of Science, Scopus, OVID, Embase, and Google Scholar. After systematic screening of the studies identified during the first step, Cochrane risk of bias tool was determined for the selected studies. The case-control and the cohort studies were investigated to assess risk of bladder cancer due to opium use. In addition, the cross-sectional studies were analysed separately to assess frequency of opium consumption. These estimates were combined using the inverse variance method. Fixed or random effect models were applied to combine the point odds ratios. The heterogeneity between the primary results was assessed using the Cochran test and I-square index. The suspected factors for heterogeneity were investigated using meta-regression models. An Egger test was conducted to identify any probable publication bias. Forest plots illustrated the point and pooled estimates. All analyses were performed using Stata version 14 software and RevMan version 5.3.

Results

We included 17 primary studies (11 case-control, one cohort and five cross-sectional) in the final meta-analysis. The total odds ratios (95% confidence intervals) for developing bladder cancer by opium use alone, and concurrent use of opium and cigarettes were estimated as 3.85 (3.05–4.87) and 5.7 (1.9–16.3) respectively. The odds ratio (95% confidence interval) for opium use with or without cigarette smoking was estimated as 5.3 (3.6–7.7).

Conclusion

This meta-analysis showed that opium use similar to cigarette smoking and maybe with similar mechanisms can be a risk factor for bladder cancer. It is therefore expected to be a risk factor for other cancers.