Occupational asbestos exposure and risk of esophageal cancer: A systematic review and meta-analysis.

Esophageal cancer (EC), which includes squamous cell carcinoma (ESCC) and adenocarcinoma (EAC), is an important cancer with poor prognosis and high mortality rate. Several occupational exposures have been associated with EC. We aim to investigate the association between occupational asbestos exposure and EC risk, considering types of asbestos and histology of the disease. We included studies mentioned in the list of references in previous reviews and pooled analyses, and we conducted an independent search in PubMed and Scopus. Forest plots of relative risks (RR) were constructed based on the association between occupational asbestos and EC risk. Random-effects models were used to address heterogeneity between 48 independent cohort and case-control studies. We found an association between occupational asbestos exposure and EC (meta-relative risk [RR] = 1.20, 95% confidence interval [CI] = 1.09-1.32; I2 = 58.8%, p-heterogeneity [het] <.001). The results of stratification by job (p-het = .20) indicate an increased RR among asbestos product workers (RR = 1.39, 95% CI = 1.07-1.81), asbestos applicators (RR = 1.41, 95% CI = 1.20-1.67), and construction workers (RR = 1.12, 95% CI = 1.02-1.24). There was no heterogeneity in meta-RR according to outcome (p = .29), geographic region (p = .69), year of publication (p = .59), quality score (p = .73), asbestos type (p = .93), study design (p = .87), and gender (p = .88), control for potential confounders (p = .20), year of first employment (p = .94) and exposure level (p = .43). The stratification analysis by histology type found an increased RR for both ESCC 1.33(1.03-1.71) and EAC 1.45(1.03-2.04) (p-het = .68). We didn't find evidence of publication bias (p = .07). The results of our study suggest that occupational asbestos exposure is associated with an increased risk of EC in both histology types.

Hospital and post-discharge mortality in COVID-19 patients with a preexisting cancer diagnosis in Iran.

BACKGROUND: Despite the severe impact of COVID-19 on cancer patients, data on COVID-19 outcomes in cancer patients from low- and middle-income countries is limited. We conducted a large study about the mortality rate of COVID-19 in cancer patients in Iran. METHODS: We analyzed data from 1,079 cancer (average age: 58.2 years) and 5,514 non-cancer patients (average age: 57.2 years) who were admitted for COVID-19 in two referral hospitals between March 2019 and August 2021. Patients were followed up until death or 31st August 2021. Multiple logistic regression models estimated the odds ratio (OR) and 95% confidence intervals (CI) of factors associated with ICU admission and intubation. The Cox regression model estimated hazard ratios (HRs) and 95% CI of factors associated with hospital and post-discharge 60-day mortalities. RESULTS: The cancer patients had higher ICU admission (OR = 1.65, 95% CI: 1.42-1.91; P-value 0.03) and intubation (OR = 3.13, 95% CI = 2.63-3.73, P-value < 0.001) than non-cancer patients. Moreover, hospital mortality was significantly higher in cancer patients than in non-cancer patients (HR = 2.12, 95% CI: 1.89-2.41, P-value < 0.001). HR for the post-discharge mortality was higher in these patients (HR = 2.79, 95% CI: 2.49-3.11, < 0.001). The hospital, comorbidities, low oxygen saturation, being on active treatment, and non-solid tumor were significantly associated with ICU admission (P-value < 0.05) in cancer patients, while only low oxygen saturation was associated with intubation. In addition, we found that old age, females, low oxygen saturation level, active treatment, and having a metastatic tumor were associated with death due to COVID-19 (P-value < 0.05). Only lung cancer patients had a significantly higher risk of death compared to other cancer types (HR = 1.50, 95% CI: 1.06-2.10, P-value = 0.02). CONCLUSION: Cancer patients are at a higher risk of ICU admission, intubation, and death due to COVID-19 than non-cancer patients. Therefore, cancer patients who are infected with COVID-19 require intensive care in the hospital and active monitoring after their discharge from the hospital.

Dietary total antioxidant capacity and odds of lung cancer: a large case-control study.

BACKGROUND& AIMS: We aimed to study the association between dietary total antioxidant capacity (dTAC) and lung cancer (LC) odds in an Iranian population. METHODS: We recruited histopathologically diagnosed LC patients and healthy subjects from 10 provinces of Iran. Trained interviewers conducted face-to-face interviews using a structured questionnaire to collect demographic and other non-dietary information. Dietary habits in the previous year were evaluated using a validated food frequency questionnaire (FFQ). We calculated daily energy and nutrient intakes using the USDA Food Composition Table. DTAC was assessed as ferric reducing antioxidant power (FRAP) and total radical-trapping antioxidant parameters (TRAP) whose scores were calculated using published databases. The odd ratios (OR) of LC and 95% confidence intervals (CI) were estimated using unconditional logistic regression after adjusting for potential confounders. Moreover, we assessed the associations in stratified groups of age, gender, tobacco including waterpipe smoking, and opium use. RESULTS: Six hundered and sixty patients and 3,412 healthy controls were included in our study. Higher FRAP and TRAP scores were associated with a lower odd of LC (FRAP, upper tertile (T3) vs. lower tertile (T1): OR = 0.53, 95% CI: 0.40-0.68; TRAP, T3 vs. T1: OR = 0.44, 95% CI: 0.33-0.57) with a significant dose-response trend for both scores (p < 0.01). The inverse association was seen for both indicators in all histologic types of LC and in all stratified analyses including male/female, tobacco smokers/nonsmokers, opium users/nonusers, water pipe users/nonusers, and subjects under/over 50 years of age. However, Interaction between none of these variables with dTAC scores was significant. CONCLUSION: Higher dTAC is associated with a lower odd of LC. The strong association in all subgroups highlights the importance of an antioxidant-rich diet intake in all subjects, even in the low-risk group.

Dietary intake of vitamin C and gastric cancer: a pooled analysis within the Stomach cancer Pooling (StoP) Project.

BACKGROUND: Previous studies suggest that dietary vitamin C is inversely associated with gastric cancer (GC), but most of them did not consider intake of fruit and vegetables. Thus, we aimed to evaluate this association within the Stomach cancer Pooling (StoP) Project, a consortium of epidemiological studies on GC. METHODS: Fourteen case-control studies were included in the analysis (5362 cases, 11,497 controls). We estimated odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the association between dietary intake of vitamin C and GC, adjusted for relevant confounders and for intake of fruit and vegetables. The dose-response relationship was evaluated using mixed-effects logistic models with second-order fractional polynomials. RESULTS: Individuals in the highest quartile of dietary vitamin C intake had reduced odds of GC compared with those in the lowest quartile (OR: 0.64; 95% CI: 0.58, 0.72). Additional adjustment for fruit and vegetables intake led to an OR of 0.85 (95% CI: 0.73, 0.98). A significant inverse association was observed for noncardia GC, as well as for both intestinal and diffuse types of the disease. The results of the dose-response analysis showed decreasing ORs of GC up to 150-200 mg/day of vitamin C (OR: 0.54; 95% CI: 0.41, 0.71), whereas ORs for higher intakes were close to 1.0. CONCLUSIONS: The findings of our pooled study suggest that vitamin C is inversely associated with GC, with a potentially beneficial effect also for intakes above the currently recommended daily intake (90 mg for men and 75 mg for women).

Occupational benzene exposure and colorectal cancer: A systematic review and meta-analysis.

Recent reports suggest that benzene exposure may be associated with solid cancers, such as lung and bladder cancers. Instead, evidence on the association between benzene and colorectal cancer (CRC) is sparse. Thus, we aimed to summarize current literature on the association between occupational benzene exposure and CRC. We searched Pubmed, Embase (through Ovid), and Scopus to retrieve cohort and nested case-control studies on the association between occupational benzene exposure and solid cancers. The search was initially completed in December 2022 and later updated in April 2024. We assessed quality of included studies using a modified version of Newcastle-Ottawa Scale. We computed pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) of CRC according to occupational benzene exposure, using the Paule-Mandel method. Twenty-eight studies were included in the meta-analysis. Most of them were conducted in Europe or North America (82.1%) and were industry-based (89.3%). Pooled RRs comparing workers exposed to benzene with those who were unexposed for incidence and mortality were 1.10 (95% CI: 1.06, 1.15) and 1.04 (95% CI: 0.97, 1.11) for CRC, 1.12 (95% CI: 1.01, 1.24) and 1.08 (95% CI: 0.99, 1.19) for colon cancer, and 1.04 (95% CI: 0.94, 1.14) and 1.05 (95% CI: 0.92, 1.19) for rectal cancer, respectively. Only one study supported the occurrence of a dose-response relationship between occupational benzene exposure and CRC, while others found no increase in risk according to dose of exposure or duration of employment. Our findings suggest that occupational benzene exposure may be associated with CRC. Further research with detailed assessment of individual-level exposure is warranted to confirm our results.

Occupational arsenic exposure and digestive and head and neck cancers: A systematic review and meta-analysis.

Arsenic is a known carcinogen for the lungs, the bladder, and the skin, while systematic evidence on other cancer types is lacking, especially for occupational exposure. Thus, we aimed to systematically summarize current evidence on the association between occupational arsenic exposure and digestive cancers, including head and neck cancer (HNC). We conducted a systematic review on Pubmed, Web of Science, and Embase search engines. We computed pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) using DerSimonian and Laird random-effects model. Occurrence of publication bias was assessed using contour-enhanced funnel plots and Egger's test. Twenty-two studies on digestive cancers and 11 on HNC were included in the meta-analysis. RRs for the association with occupational exposure to arsenic of 1.23 (95% CI: 1.07-1.40; I2 = 72.3%, p < 0.001) and 1.08 (95% CI: 0.76-1.53; I2 = 76.6%, p < 0.001) for digestive cancer and HNC, respectively, were observed. As for specific cancer types, arsenic was associated with rectal cancer (RR: 1.51; 95% CI: 1.003-2.28; I2 = 37.0%, p = 0.174), but not with other investigated cancer types. No clear evidence of publication bias was found. The results of our study suggest that the observed association between occupational arsenic exposure and digestive cancer might be mainly driven by a positive association for rectal cancer, while arsenic exposure did not appear to be associated with HNC. However, further high-quality studies with detailed assessment of arsenic exposure are warranted to clarify the potential association of arsenic with digestive cancers and HNC.

Occupational benzene exposure and risk of head and neck cancer: A systematic review and meta-analysis.

INTRODUCTION: Benzene, an aromatic hydrocarbon, is a well-known leukemogen. To date, the link between benzene exposure and solid cancers is under examination. Our objective is to perform a systematic review and meta-analysis to evaluate if the occupational exposure to benzene is associated with the incidence and mortality of head and neck cancers (HNCs). METHODS: We systematically reviewed the literature for pertinent cohort studies mentioned in the most recent IARC Monograph on benzene working exposure and other cohorts and case-controls identified via a literature search performed in PubMed, Scopus, and Embase, from their inception to March 2024. Stratified multilevel meta-analyses according to study design, cancer type, industrial sector, quality score of the articles, geographic region and risk of exposure bias were conducted. RESULTS: A total of 29 independent studies were included in our review and multilevel meta-analysis. The findings revealed a bordeline association between exposure to occupational benzene and incidence of HNCs RR = 1.27, 95% CI = 1.00-1.64, I2 level2 = 0%, I2level3 = 43.30%, P < 0.05). In addition, we found a significant increased overall risk of HNCs in females (RR = 1.68, 95% CI = 1.07-2.61; I2level2 = 0%, I2level3 = 0%, P = 0.433). Stratification analysis according to cancer sites showed a significant increase in risk of nose & sinuses cancers (RR = 3.72, 95% CI = 2.07-6.68; I2level2 = 34.13%, I2level3 = 0%, P = 0.17). European cohorts (RR = 1.31, 95% CI = 1.08-1.59, p < 0.01) and lower quality studies (RR = 1.39, 95% CI = 1.00-1.91; I2level2 = 0%, I2level3 = 45.94%, P < 0.001). No evidence of publication bias was found (Egger test P = 0.103). CONCLUSIONS: In conclusion, this systematic review and meta-analysis provide evidence that workers with occupational exposure to benzene might be at increased risk of HNCs, in particular for nose & sinuses cancer. However, it is essential to consider the limitations of the studies, particularly residual confounding, and the areas that need further study to improve our understanding of the subject.

Occupational Exposure to Benzene and Risk of Breast Cancer: Systematic Review and Meta-Analysis.

INTRODUCTION: Benzene is a recognized carcinogen; however, its association with breast cancer is not well established. Hence, a meta-analysis of cohort and case-control studies was performed to determine the association between occupational benzene exposure and the risk of breast cancer. METHODS: A systematic literature review identified 7573 publications from which 23 cohort and case-control studies were retained and evaluated using meta-analyses (fixed effects model). PRISMA guidelines were followed. Our protocol was registered in the PROSPERO database (Registration No. CRD42022379720). Study quality was assessed using a modified Newcastle-Ottawa scale (NOS). RESULTS: The summary relative risk (RR) for ever-benzene exposure was 1.08 (95% CI=1.03-1.14, I2=38.6%, n=23 risk estimates); corresponding RR for cancer incidence and mortality were 1.08 (95% CI=1.02-1.14, I2=56.1%, n=16) and 1.10 (95% CI=0.87-1.37, I2<0.001%, n=10). However, heterogeneity was detected for sex (p-het=0.002), publication year (p-het<0.001), study design (p-het<0.001), study quality (p-het<0.001), and industry of employment (p-het=0.03). The RR for high level of exposure showed positive association with breast cancer 1.35 (95% CI=1.06-1.72, I2 =<0.001%, n=3) and (P-het=0.64). Publication bias was detected (p=0.03). CONCLUSIONS: The results of our meta-analysis indicate a positive association between occupational benzene exposure and an increased risk of breast cancer, particularly when exposed to higher levels of benzene. However, bias and confounding could not be excluded.

Opium use and risk of colorectal cancer: a multi-center case-referent study in Iran.

BACKGROUND: Opium use has been associated with an increased risk of cancers of the lung, oesophagus, and pancreas, and it was recently classified by the International Agency for Cancer Research as carcinogenic to humans. It is not clear whether opium also increases the risk of colorectal cancer (CRC). The aim of our study was to assess the association between various metrics of opium use and the risk of CRC. METHODS: This case-referent study from seven provinces in Iran comprised 848 CRC cases and 3215 referents. Data on opium use (duration, amount, frequency) and potential confounders were collected by trained interviewers. Multivariable unconditional logistic regression models were used to measure odds ratios (OR) adjusted for age, gender, province, marital status, family history of CRC-linked cancers, consumption of red meat, fruits and vegetables, body shape, occupational physical activity, and socioeconomic status. RESULTS: Regular opium consumption was not associated with the risk of CRC (OR 0.9, 95% confidence interval, CI: 0.7, 1.2) compared to subjects who never used opium. However, frequent opium use more than twice a day was associated with an increased risk of CRC compared to non-users of opium (OR: 2.0, 95% CI: 1.1, 3.8; p for quadratic trend 0.008). CONCLUSION: There seems to be no overall association between opium use and CRC, but the risk of CRC might be increased among persons who use opium many times a day.

Role of chest CT scan in patients with preexisting cancer and COVID-19 pneumonia.

BACKGROUND: Detection of COVID-19 in cancer patients is challenging due to probable preexisting pulmonary infiltration caused by many infectious and non-infectious etiologies. We evaluated chest CT scan findings of COVID-19 pneumonia in cancer patients and explored its prognostic role in mortality. METHODS: We studied 266 COVID-19 patients with a history of cancer diagnosis between 2020 and 2022. Chest CT images were reported based on Radiological Society of North America (RSNA) structural report and the CT score and pattern of involvement were noted. We used multivariate logistic regression models to determine the association between CT scan findings and mortality of the cancer COVID-19 patients. RESULTS: The mean age was 56.48 (± 18.59), and 53% were men. Gastrointestinal (29.3%), hematologic (26.3%), and breast (10.5%) cancers were the most frequent types of cancer. The prevalence of atypical or indeterminate findings in the chest CT was 42.8%. Most radiologic findings were consolidation mixed with ground-glass opacity (44.4%), pleural effusion (33.5%), and pure ground-glass opacity (19.5%). The risk of death was higher among those who had typical chest CT for COVID-19 (OR 3.47; 95% CI 1.14-8.98) and those who had a severity of score higher than 18 (OR 1.89; 95% CI 1.07-3.34). Also, presence of consolidation (P value 0.040), pleural effusion (P value 0.000), centrilobular nodules (P value 0.013), and architectural distortion (P value 0.005) were associated with a poorer prognosis. CONCLUSION: Less than half of COVID-19 patients with a history of cancer had typical imaging features of COVID-19. Radiologists should be aware of atypical, rare, or subtle chest CT findings in patients with pre-existing cancer.

Per- and Poly-fluoroalkyl Substances (PFAS) Exposure and Risk of Kidney, Liver, and Testicular Cancers: A Systematic Review and Meta-Analysis.

INTRODUCTION: Per- and poly-fluoroalkyl substances (PFASs) are a large, complex group of synthetic chemicals humans can be exposed to from occupational or environmental sources. In this systematic review and meta-analysis, we examined the association between PFAS exposure, particularly Perfluorooctanoic Acid (PFOA), and Perfluorooctane Sulfonic Acid (PFOS), and risk of kidney, liver, and testicular cancer. METHODS: We systematically searched PubMed to identify cohort and case-control studies reported after the Monograph of the International Agency for Research on Cancer and the Toxicological Profile of the Agency for Toxic Substances and Disease Registry. We assessed the quality of the studies by using a modified version of the Newcastle-Ottawa Scale (NOS). Forest relative risk (RR) plots were constructed for liver, kidney, and testicular cancer. We conducted stratified analyses by geographic region, study design, quality score, outcome, years of publication, exposure source, and PFAS type. A random-effects model was used to address heterogeneity between studies. RESULTS: Fifteen studies, including ten cohort studies, three case-control studies nested in a cohort, and two case-control studies were included after removing duplicate and irrelevant reports. We found an association between overall PFAS exposure and the risk of kidney cancers (RR=1.18, 95% CI =1.05-1.32; I =52.8%, 11 studies). Also, we showed an association between high-level exposure to PFAS and kidney cancer (RR=1.74, 95% CI =1.23-2.47; p=0.005) and testicular cancer (RR=2.22, 95% CI =1.12-4.39; p=0.057). There was no association with liver cancer. We found no heterogeneity by geographical region, PFAS type, study design, outcome, quality score, year of publication, or exposure source. Only two studies reported results among women. CONCLUSIONS: We detected an association between overall PFAS exposure and kidney cancer and high doses of PFAS with testicular cancer. However, bias and confounding cannot be excluded, precluding a conclusion in terms of causality.

Incidence of symptomatic COVID-19 in close contacts of patients after discharge from hospital.

BACKGROUND: There is a little evidence about the infectiousness of recovered COVID-19 patients. Considering that the circumstance of the isolation of the COVID-19 patients after-discharge is not always optimal, it is not very unlikely that viral transmission still occurs after hospital discharge. This study aims to investigate the incidence of symptomatic COVID-19 in close contacts of recovered patients after discharge from hospital. METHODS: Four hundred fifty discharged COVID-19 patients discharged from the largest public treatment center in Tehran, capital city of Iran, were followed up. Demographic and clinical data of participants were collected from medical records. Follow-up data were acquired via telephone call interviews with patients or their main caregivers at home. RESULTS: The study's response rate was 93.77% (422 participated in the study). 60.90% patients were male and 39.10% were female (sex ratio = 1.55 male). The most prevalent comorbidities in these patients were hypertension (29.68%) and diabetes (24.80%). The mean of home isolation after discharge was 25.85. Forty-one (9.71%) patients had at least one new case in their close contacts, up to 3 weeks after they were discharged. There was a significant association between having at least a comorbidity with the odds of getting infected in close contacts [OR (CI) 2.22 (1.05-4.68)]. Density of inhabitant per room in a house' and the quality of isolation had significant associations with observing new cases in the patients' close contacts [high to moderate; OR (CI) 2.44 (1.06-5.61], [bad to good; OR (CI) 2.31 (1.17-4.59)], respectively. CONCLUSION: After hospital discharge, COVID-19 transmission can still occur, when a large number of people lives together in a single house. Another explanation can be that the less precaution measures are taken by recovered patients' cohabitants. Such conditions are also likely to happen when the recovered patient has other chronic diseases and requires additional care.

The effect of nutrition education for cancer prevention based on health belief model on nutrition knowledge, attitude, and practice of Iranian women.

BACKGROUND: In recent years, nutrition has received an increasingly important role in the etiology of cancer. Thus, public education about dietary factors associated with cancer risk or prevention could be an important intervention for cancer prevention, particularly in low- and middle-income countries where the burden of cancer is increasing rapidly and the access to care is limited. The age-standardized incidence of breast cancer was 35.8 among Iranian women in 2020. We aimed to study the effect of nutrition education on the knowledge, attitude, and practice of Iranian women towards dietary factors related to cancer. METHODS: In this interventional study, 229 women from public health centers were recruited and underwent three 75-min sessions of education based on the Health Belief Model (HBM). Participants were interviewed by trained interviewers using a validated and reproducible nutrition-related cancer prevention knowledge, attitude, and practice questionnaire (NUTCANKAP) questionnaire designed based on the HBM. Nutritional knowledge, attitude, and practice of participants were assessed through this questionnaire. Three 24-h dietary recalls (one weekend and two nonconsecutive weekdays) were also collected before and one month after the intervention. RESULTS: The mean age of the participants was 45.14 years, and the mean BMI was 27.2 kg/m2. After the intervention, the participants had a higher intake of whole grain (p = 0.03) and a lower fat dairy (p = 0.009) and nuts (p = 0.04). However, the intake of high-fat dairy (p = 0.001) decreased after the intervention. We indicated significant differences in knowledge (p < 0.001) and nutritional practice scores (p = 0.01) after education. In addition, after the intervention, there were significant differences in the mean score of the HBM components, except for the perceived self-efficacy. CONCLUSION: Participation in a nutrition education program positively impacted the knowledge and nutritional practices linked to cancer prevention.

Opium use and the risk of head and neck squamous cell carcinoma.

Scant evidence exists to support the association of opium use with head and neck cancer, limited to the larynx and oral cavity. In a multicenter case-control study-Iran Opium and Cancer study, we recruited 633 cases of head and neck squamous cell carcinoma (HNSCC) (254 lip and oral cavity, 54 pharynx, 327 larynx and 28 other subsites within the head and neck) and 3065 frequency-matched controls from April 2016 to April 2019. Odds ratios (ORs) for opium use and 95% confidence intervals (95% CIs) were obtained using mixed-effects logistic regression because of heterogeneity among centers. The adjusted OR (95% CI) for regular opium use was 3.76 (2.96-4.79) for all HNSCC combined. Strong dose-response effects were observed by frequency or amount of use, and duration of use. Regular opium uses significantly increased the risk of HNSCC of the pharynx, larynx and other subsites within the head and neck with OR (95% CI) of 2.90 (1.40-6.02), 6.55 (4.69-9.13) and 5.95 (2.41-14.71), respectively. The observed associations were significant even among never tobacco smokers (including cigarette and water-pipe smoking). Moreover, by the multiplicative interaction scale, the effect of opium use could be varied by cigarette smoking on HNSCC, 8.16 (6.20-10.74). For the first time, the current study showed opium users have an increased risk of several anatomic subsites of HNSCC.

Dietary N-nitroso compounds intake and bladder cancer risk: A systematic review and meta-analysis.

Bladder cancer is the most common cancer of the urinary tract. While tobacco smoking is responsible for more than half of the bladder cancer cases, occupational exposures is also an established risk factor of bladder cancer. Strong evidence of carcinogenicity of N-nitroso compounds (NOCs) have been provided in animal and human studies, but the target organ of occurring cancer in human including bladder cancer is still obscure. A wide range of NOCs sources surrounded us like diet, drinking water, cigarette smoking, workplace, and indoor air population. We conducted a meta-analysis to elucidate the association between NOCs in drinking water and food source and bladder cancer risk. Ten articles were included after removing the duplicates and irrelevant articles. The majority studies of our meta-analysis was done on women, maybe because of cigarette smoking as a main risk factor among men which is more common among men than women. Although the number of articles was limited our meta-analysis showed no significant association between dietary intakes of NOCs and bladder cancer risk (OR = 0.96, 95% CI = 0.88, 1.05; I2 = 50%, P-value = 0.007), neither subgrouping of NOCS type and source of NOCs nor dose of nitrate and nitrite intake indicated any associations.

Opium use reporting error in case-control studies: neighborhood controls versus hospital visitor controls.

Background: There are relatively scant data to determine whether hospital visitors could serve as a proper source of controls in case-control studies of illicit drug use. The aim of this study was to evaluate using neighborhood versus hospital visitor controls in reporting opium use. Methods: We used data from 2 independent case-control studies of cancer in Iran. In the first study, controls were selected from neighborhoods of the patients. For the second one, controls were selected from among hospital visitors. In the latter study, hospital visitors were companions of the patients or others visiting the hospital for reasons other than disease treatment. We used stata (version 12; Stata Corp( for all analyses and with a significance level of 0.05. Results: Data from 616 of neighborhood controls and 414 of hospital visitor controls were analyzed. Opium point prevalence among men was significantly higher in hospital visitors than neighborhood controls (43.3% vs 32.2%; P = 0.047), while the prevalence of cigarette smoking was very similar in both control groups (46.3% vs 47.2%; P =.847). Using a logistic regression analysis, in an unadjusted analysis, neighborhood controls were less likely to report opium use in both genders, with (unadjusted OR = 0.77; 95% CI: 0.59,1). After adjusting for potential confounders, the differences of opium use between the 2 control groups became more pronounced (Adjusted OR = 0.26; 95% CI: 0.10, 0.69). Conclusion: Because of the similarity of reporting cigarette smoking among neighborhood controls but substantially lower reporting of opium use among them, we concluded that neighborhood controls underreport opium use-a sensitive question- and that using neighborhood control biases the findings in case-control studies. Hospital visitor controls may be more appropriate than neighborhood controls for case-control studies of illicit drugs.

Occupational exposure to diesel exhaust and head and neck cancer: a systematic review and meta-analysis of cohort studies.

Exposure to diesel exhaust (DE) and other fossil fuels in the workplace can cause several health effects including cancer. We conducted a systematic review and meta-analysis of cohort studies examining the association between occupational DE exposure and the risk of head and neck cancer (HNC), including cancer of the oral cavity, pharynx and larynx. We included cohort studies mentioned in the Monograph of the International Agency for Research on Cancer, 2014, on DE. Forest plots of relative risk (RR) were constructed for HNC overall and its anatomical subtypes. A random-effects model was used to address heterogeneity between studies. Fifteen articles were included after removing duplicates and irrelevant reports. The summary RR for DE exposure was 1.08 [95% confidence interval (CI) = 1.01-1.17, P heterogeneity = <0.001] for HNC overall, 0.98 (95% CI = 0.87-1.11) for oral cavity, 1.05 (95% CI = 0.77-1.43) for pharyngeal, 1.15 (95% CI = 0.96-1.38) for oral cavity and pharyngeal combined, and 1.13 (95% CI = 1.03-1.24) for laryngeal cancer. There were elevated RRs for incidence studies of HNC (RR = 1.13; 95% CI = 1.05-1.22, P  = 0.001), European studies (RR = 1.13; 95% CI = 1.05-1.23, P  = 0.001), and female studies (RR = 1.77; 95% CI = 1.31-2.39, P  = 0.003). Our study suggested an association between occupational DE exposure and the risk of HNC, particularly laryngeal cancer. Although residual confounding cannot be ruled out, our results support the importance of controlling occupational DE exposure.

Occupational benzene exposure and risk of kidney and bladder cancers: a systematic review and meta-analysis.

INTRODUCTION: Benzene is recognized as leukemogenic. However, the association between it and solid cancers has been the subject of less investigation. We aim to conduct a systematic review and meta-analysis to evaluate the association between occupational exposure to benzene and the risk of urinary tract cancer, including kidney and bladder. METHODS: We included 41 cohort and case-control studies listed in the most recent International Agency for Research on Cancer (IARC) Monograph on benzene exposure and the result of a literature review to identify more recent studies. Forest plots of relative risk (RR) were constructed for kidney, bladder, and urinary tract cancer overall. A random-effects model was used to address heterogeneity between studies. Stratified analyses were conducted to explore effect modification. RESULTS: Our findings revealed an association between exposure to occupational benzene and kidney and unspecified urinary tract cancers (RR = 1.20, 95% confidence interval = 1.03-1.39), and an association of borderline statistical significance with bladder cancer (RR = 1.07, 95% confidence interval = 0.97-1.18). Publication bias was excluded for both kidney (P = 0.809) and bladder cancer (P = 0.748). Stratification analysis according to the selected study characteristics showed no difference except regarding the industry for kidney cancer (P < 0.000), with a stronger association in the chemical industry. An analysis by exposure level did not reveal any trend for kidney cancer, whereas there was a trend (P = 0.01) for bladder cancer. CONCLUSION: Our study found an association between occupational benzene exposure and kidney cancer and a dose-effect association between benzene exposure and bladder cancer.

Role of dietary intake of specific polyunsaturated fatty acids (PUFAs) on colorectal cancer risk in Iran.

High-fat diets have been associated with colorectal cancer (CRC) risk, and the role of polyunsaturated fatty acids (PUFAs) has been reported to vary based on the length of PUFAs. We explored the association between dietary omega-6 and omega-3 PUFAs intake and CRC. We analyzed 865 CRC patients and 3206 controls from a case-control study of Iran (IROPICAN study). We used multivariate logistic regression models to calculate the odds ratios (OR) and 95% confidence intervals (CI) for the association between PUFAs intake and CRC risk. Our results showed that gamma-linolenic acid (18:3 n-6, GLA), arachidonic acid (20:4n-6, ARA), a-linolenic acid (Cis-18:3n-3, ALA), eicosapentaenoic acid (20:5n-3, EPA), docosahexaenoic acid (22:6n-3, DHA) consumption was not associated with the risk of CRC. However, the OR of linoleic acid (18: 2n-6, LA) intake was 1.47 (95% CI 1.01-2.14, p = 0.04) for proximal colon and that of docosapentaenoic acid (22:5n-3, DPA) intake was 1.33 (95% CI 1.05-1.69, p = 0.01) for rectum. This study indicates a high level of LA is associated with an increased risk of proximal colon cancer, and DPA intake was positively associated with rectum cancer risk. Furthermore, our study noted a high intake of n-6 (from vegetable oils) compared to n-3 PUFAs (from fish and seafood) in this population. Public awareness and government support is needed to increase fish and seafood production and consumption in Iran.

Determinants of early-onset colorectal cancer: a multicenter case-control study in Iran.

BACKGROUND: We aimed to study the risk factors of early-onset colorectal cancer (CRC) incidence in the Iranian population. Early onset CRC in Iran is a relevant health issue that deserves further epidemiological efforts to be defined and controlled as far as possible. Early age screening of low-tract of the intestine would be particularly useful in families of colorectal cancer patients. METHODS: We analyzed data from a multicenter hospital-based case-control study in Iran (The Iranian Study of Opium and Cancer). Sociodemographic and lifestyle information was collected using validated questionnaires. Multivariate logistic regressions estimated the odds ratios (OR) and 95% confidence intervals (CIs) for the association of early-onset CRC in individuals under the age of 50 and potential risk factors, including physical activity, socioeconomic status, body shape at age 15, dietary factors, vitamin D, cigarettes and waterpipe smoking, opium use and family history of CRC. Additionally, a subgroup analysis was conducted for individuals with a very young age of CRC onset (i.e. <35 years). RESULTS: We analyzed data of 189 developed CRC below age 50 (99 colon and 90 rectum), and 66 patients under the age 35 (13 colon and 21 rectum). Early CRC was inversely associated with vegetables (OR, 0.59; 95% CI, 0.38-0.92 for 422-576 g/day) and vitamin D (OR, 0.49; 95% CI, 0.26-0.94), and positively associated with red meat intake (OR, 1.80; 1.15-2.83 per 25.65 g/day). Vegetables (OR, 0.51; 95% CI, 0.27-0.98 for 576 g/day), red meat (OR, 2.05; 95% CI, 1.11-3.79 for 25.65 g/day), vitamin D (OR, 0.29; 95% CI, 0.10-0.86) and opium use (OR, 2.61; 95% CI, 1.01-6.74) were associated with early rectum cancer. Results were heterogeneous by cancer site for high fruit and vegetables intakes and cigarette smoking. Family history was associated with CRC (OR, 3.16; 95% CI, 1.29-10.9) and rectum cancer (OR, 3.22; 95% CI, 1.24-14.4) in subjects younger than 35, and, to a lesser extent, with CRC and rectum cancer before age 50. CONCLUSION: Early-onset CRC was related to the intake of vegetables, vitamin D and red meat in Iran. Early-onset rectum cancer was associated with regular opium use. Family history was associated with early CRC and early rectum cancer, particularly below the age of 35.