Unveiling an Association between Waterpipe Smoking and Bladder Cancer Risk: A Multicenter Case-Control Study in Iran.

BACKGROUND: Limited data exist for the association between bladder cancers and waterpipe smoking, an emerging global public health concern. METHODS: We used the IROPICAN database in Iran and used multivariable logistic regression, adjusting for cigarette smoking, opium use, and other confounding factors. In addition, we studied the association between exclusive waterpipe smoking and bladder cancer. RESULTS: We analyzed 717 cases and 3,477 controls and a subset of 215 patients and 2,145 controls who did not use opium or cigarettes. Although the OR adjusted for opium, cigarettes, and other tobacco products was 0.92 [95% confidence interval (CI), 0.69-1.20], we observed a statistically significant elevated risk in exclusive waterpipe smokers (OR = 1.78; 95% CI, 1.16-2.72) compared with non-users of opium or any tobacco. Associations were strongest for smoking more than two heads/day (OR = 2.25; 95% CI, 1.21-4.18) and for initiating waterpipe smoking at an age less than 20 (OR = 2.73; 95% CI, 1.11-6.72). The OR for urothelial bladder cancer was higher in ex-smokers (OR = 2.35; 95% CI, 1.24-4.42) than in current smokers (OR = 1.52; 95% CI, 0.72-3.15). All observed associations were consistently higher for urothelial histology. CONCLUSIONS: Waterpipe smoking may be associated with an increased risk of bladder cancer, notably among individuals who are not exposed to cigarette smoking and opium. IMPACT: The study provides compelling evidence that waterpipe smoking is a confirmed human carcinogen, demanding action from policymakers. See related In the Spotlight, p. 461.

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.

Evaluation of Laboratory Findings of Patients with Coronavirus Disease 2019 in Kerman, Iran.

Background & Objective: Since December 2019 in Wuhan, China there is a new form of pneumonia and after expansion in other countries, World Health Organization (WHO) called it Coronavirus Disease 2019 (COVID-19). Since the clinical laboratory findings have played an important role in the progression of the disease, this study aimed to evaluate the laboratory findings in COVID-19 patients (before vaccination). Methods: In this case-control study that was conducted from February to August 2020; the laboratory test status in 101 positive COVID-19 patients was evaluated and compared with 101 healthy individuals. Results: The results of our study showed that 21% of patients had low WBC, 24.75% low RBC, 37.62%, low Hb, 18.81% with low HCT, 29.7%, low Plt, 41.58% had High PT, 71.29% high CRP, 17.82% high urea, 11.88% high CR, 15.84% high LDH, 10.89% low sodium, 14.75% low potassium (K). The quantitative examination of blood factors showed that lymph%, mixed%, PLT, HCT, Hb, and RBC were higher in the control group than in the case group. While Neu%, WBC, PTT, CRP, UREA, LDH, K in the patient group were higher than in the control group. Conclusion: According to the results of the study, it can be concluded that in the clinical treatment of COVID-19 patients, much attention should be paid to the laboratory indicators to identify and intervene early in critically ill patients.

Dietary total antioxidant capacity and head and neck cancer: a large case-control study in Iran.

Background: Data on the association between head and neck cancer (HNC) and dietary factors are inconclusive. No study has so far investigated the association between dietary total antioxidant capacity (dTAC) and HNC concerning interactions with other risk factors. Method: Pathologically confirmed new diagnosed HNC patients were included in this study. The control group was healthy hospital visitors who were frequently matched with patients on age (5 years interval), gender, and province of residence. Trained interviewers administered a validated Food Frequency Questionnaire (FFQ) to assess the participants' food intake 1 year before the cancer diagnosis. Data on TAC scores of foods was collected by Ferric Reducing Antioxidant Power (FRAP) and Total Radical-trapping Antioxidant Parameters (TRAP) from published data. We applied logistic regression adjusted for age, sex, energy intake, socioeconomic status, province, opium use, alcohol use, physical activity, and dental health. We also studied the interaction of dTAC with tobacco smoking status, and opium use on the risk of HNC. Results: We recruited 876 HNC patients and 3,409 healthy controls. We observed a significant decrease in the odds of HNC with increasing dTAC scores. The OR of HNC for the third vs. the first tertile was 0.49 (95%CI 0.39-0.61) for FRAP and 0.49 (95%CI 0.39-0.62) for TRAP. Both dTAC scores were inversely associated with lip and oral (T3 ver. T1 OR = 0.51; 95%CI 0.36-0.71 for FRAP and OR = 0.59; 95% CI 0.44-0.82 for TRAP) and larynx (T3 ver. T1 OR = 0.43; 95%CI 0.31-0.61 for FRAP and OR = 0.38; 95% CI 0.26-0.55 for TRAP) cancers. There was no interaction between tobacco smoking, opium use; and TRAP or FRAP on the risk of HNC. Conclusion: An antioxidant-rich diet in terms of FRAP or TRAP could decrease the risk of HNC and its subtypes.

Population attributable proportion and number of cancer cases attributed to potentially modifiable risk factors in Iran in 2020.

In the current study, we aimed to calculate the fraction of cancer attributable to modifiable risk factors in Iran in 2020. Population attributable fractions (PAFs) were calculated for established cancer risk factors using three data sources: the national cancer incidence reports, relative risks extracted from global and national meta-analyses, and exposure prevalence from national/subnational population-based surveys. In addition to overall cancers, the PAFs were estimated separately for each cancer site among men and women. Overall, 32.6% of cancers in 2020 in Iran were attributable to known risk factors. The PAF in men (40.2%) was twice as high as in women (21.1%). Cigarette smoking (15.4%), being overweight (5.0%), opium use (3.9%) and H. pylori infection (3.8%) were the leading causes of cancers. For men, the highest PAFs belonged to cigarette smoking (26.3%), opium use (6.8%) and being overweight (3.1%), while for women, the highest PAFs belonged to being overweight (7.2%), H. pylori infection (2.7%) and cigarette smoking (2.7%). Among Iranian men and women, the PAFs of waterpipe smoking were 2% and 0.9%, respectively. A third of incident cancers in Iran are due to modifiable exposures, mainly cigarette smoking, being overweight, and H. pylori infection. Opium consumption and waterpipe smoking collectively accounted for 8.8% of cancer occurrence in men and 1.3% in women in Iran. These emerging risk factors should be taken into consideration in future PAF studies.

The Impact of Socioeconomic Inequality on Mental Health among Adolescents in Qazvin, Iran: Blinder-Oaxaca Decomposition Method.

Background: Mental health is integral to public health in adolescents. Although previous studies have shown that low socioeconomic status (SES) is associated with mental disorders (MD), it is unclear which mental health domains are most important. Thus, our study aimed to investigate the associations between 5 domains of mental disorder and SES inequality in adolescents. Methods: We conducted a cross-sectional study among adolescents (N = 1724). Associations between SES inequality with mental disorders, such as emotional symptoms, conduct problems, hyperactivity, peer relationship problems, and prosocial behavior, were examined. We used the concentration index (CI) to determine inequality. The gap between the low and high socioeconomic groups was decomposed into its determinants using the Blinder-Oaxaca decomposition method. Results: Mental health's overall CI was -0.085 (P ˂ 0.001). The emotional problem was primarily caused by SES inequality (-0.094 [P = 0.004]). Decomposition of the gap between the 2 economic groups showed that physical activity, school performance, exercise, parents' smoking status, and gender were the most important determinants of inequality. Conclusion: SES inequality plays a vital role in adolescents' mental health. It seems that the emotional problem domain of mental health might be more amenable to interventions than other domains.

Regional disparities in cancer survival in Iran: Insight from a National Surveillance of Cancer Survival in Iran (IRANCANSURV).

BACKGROUND AND OBJECTIVES: We aimed to investigate geographical disparity in cancer survival in 9 provincial population-based cancer registries in Iran from 2015 to 2016. MATERIAL AND METHOD: In the current study, data from 90,862 adult patients (aged >15 years) diagnosed with cancer were retrieved from 9 population-based cancer registries across Iran. Five-year survival rates were estimated by applying relative survival approaches. We also applied the international cancer survival standard weights for age standardization. Finally, we calculated the excess hazard ratio (EHR) for each province adjusted for age, sex, and cancer sites to estimate the excess hazard ratio of mortality compared to the capital province (Tehran). RESULTS: The largest gap in survival was observed in more curable cancer types, including melanoma (41.4%), ovary (32.3%), cervix (35.0%), prostate (26.7%), and rectum (21.4%), while the observed geographical disparity in lethal cancers such as lung, brain, stomach, and pancreas was less than 15%. Compared to Tehran, we found the highest excess hazard of death in Western Azerbaijan (EHR=1.60, 95% CI 1.51, 1.65), Kermanshah (EHR=1.52, 95% CI=1.44, 1.61), and Kerman (EHR=1.46, 95% CI=1.38, 1.53). The hazard ratio of death was almost identical in Isfahan (EHR=1.04, 95% CI=1.03, 1.06) and Tehran provinces. CONCLUSION: Provinces with higher HDI had better survival rates. IRANCANSURV study showed regional disparities in cancer survival in Iran. Cancer patients in provinces with a higher Human Development Index (HDI) had a higher survival rate and lived longer compared to the patients in provinces with medium and low HDI regions.

Association of Dietary Nitrate, Nitrite, and N-Nitroso Compounds Intake and Gastrointestinal Cancers: A Systematic Review and Meta-Analysis.

N-nitroso compounds (NOCs) are a class of chemical carcinogens found in various environmental sources such as food, drinking water, cigarette smoke, the work environment, and the indoor air population. We conducted a systematic review and meta-analysis to investigate the links between nitrate, nitrite, and NOCs in food and water and the risk of gastrointestinal (GI) cancers, including esophageal cancer (EC), gastric cancer (GC), colorectal cancer (CRC), and pancreatic cancer (PC). A systematic search of the literature in Scopus, PubMed, Google Scholar, Web of Science, ScienceDirect, and Embase was performed for studies on the association between NOCs in drinking water and food sources and GI cancers. Forest plots of relative risk (RR) were constructed for all the cancer sites and the intake sources. The random-effects model was used to assess the heterogeneity between studies. Forty articles were included after removing duplicate and irrelevant articles. The meta-analysis indicated that the intake of high dose vs. low dose of these compounds was significantly associated with the overall GI cancer risk and nitrite (RR = 1.18, 95% CI = 1.07-1.29), and N-nitrosodimethylamine (NDMA) (RR = 1.32, 95% CI = 1.06-1.65). We found that dietary nitrite intake increased GC (RR = 1.33, 95% CI = 1.02-1.73), and EC (RR = 1.38, 95% CI = 1.01-1.89). Additionally, dietary NDMA intake increased the risk of CRC (RR = 1.36, 95% CI = 1.18-1.58). This meta-analysis provides some evidence that the intake of dietary and water nitrate, nitrite, and NOCs may be associated with GI cancers. In particular, dietary nitrite is linked to GC and EC risks and dietary NDMA intake is associated with CRC.

Geographic distribution and time trends of water-pipe use among Iranian youth and teenage students: A meta-analysis and systematic review.

Water-pipe tobacco smoking is harmful to health, yet its rate of prevalence remains uncertain. Recent evidence has shown that the prevalence of water-pipe smoking among students is higher than in the general population. In this study, a systematic review of related literature on water-pipe use was conducted, and for this purpose, 76 articles were examined in the study. In this vein, geographic distribution and time trends of water-pipe consumption in Iran were considered. The results of this study showed that lifetime, last-year, and last-month prevalence of water-pipe smoking use among Iranian students were 28.78 (25.07-32.49), 20.84 (16.01-25.66), and 16.36 (11.86-20.85), respectively. The results also showed a wide variation by the region and sex in Iran. This study has shown the importance of addressing public prevention and alerting programs in schools and universities.

Opium use and risk of lung cancer: A multicenter case-control study in Iran.

Opium use was recently classified as a human carcinogen for lung cancer by the International Agency for Research on Cancer. We conducted a large, multicenter case-control study evaluating the association between opium use and the risk of lung cancer. We recruited 627 cases and 3477 controls from May 2017 to July 2020. We used unconditional logistic regression analyses to estimate the odds ratios (OR) and 95% confidence intervals (CI) and measured the association between opium use and the risk of lung cancer. The ORs were adjusted for the residential place, age, gender, socioeconomic status, cigarettes, and water pipe smoking. We found a 3.6-fold risk of lung cancer for regular opium users compared to never users (95% CI: 2.9, 4.6). There was a strong dose-response association between a cumulative count of opium use and lung cancer risk. The OR for regular opium use was higher for small cell carcinoma than in other histology (8.3, 95% CI: 4.8, 14.4). The OR of developing lung cancer among opium users was higher in females (7.4, 95% CI: 3.8, 14.5) than in males (3.3, 95% CI: 2.6, 4.2). The OR for users of both opium and tobacco was 13.4 (95% CI: 10.2, 17.7) compared to nonusers of anything. The risk of developing lung cancer is higher in regular opium users, and these results strengthen the conclusions on the carcinogenicity of opium. The association is stronger for small cell carcinoma cases than in other histology.

Opium Use and the Risk of Liver Cancer: A Case-Control Study.

Limited evidence is available to acknowledge the association between opium use and liver cancer. In a case-control study, we recruited 117 cases of primary liver cancer (PLC) and 234 age and sex-matched neighborhood controls from 2016 to 2018. We calculated odds ratios (OR) for opium use and 95% confidence intervals (95% CI), using conditional logistic regressions. Compared with non-users the adjusted OR (AOR, 95% CI) for opium use was 6.5 (95% CI, 2.87-13.44). Compared with people who had no history of use, a strong dose-response effect of opium use was observed by amount of use (AOR, 10.70; 95% CI, 3.92-28.70). Cumulative use of opium also indicated that using over 30 gr-year could increase the PLC risk dramatically (AOR, 11.0; 95% CI, 3.83-31.58). Those who used opium for more than 21 years were highly at risk of PLC (AOR, 11.66; 95% CI, 4.43-30.67). The observed associations were significant even among never tobacco smokers (including cigarette and water-pipe smoking). PREVENTION RELEVANCE: The results of this study indicate that opium use dramatically increased the risk of liver cancer. Because opioids are increasing for medical and non-medical use globally; accordingly, severe health consequences such as liver cancer have to be investigated widely.

Dietary Ruminant and Industrial Trans-Fatty Acids Intake and Colorectal Cancer Risk.

As colorectal cancer (CRC) is largely due to modifiable lifestyle habits, the awareness on its risk factors is highly important. Dietary fatty acids have been linked to CRC risk. We explored the association between dietary trans fatty acids (TFAs) intake and CRC risk. We analyzed 865 CRC cases (434 in colon and 404 in rectum) and 3206 controls of the IROPICAN study, with data collected by trained interviewers using validated questionnaires. TFAs intake (industrial and ruminant types) was categorized into quartiles. Multivariate logistic regression models were built to calculate the odds ratios (OR) for the association between CRC and TFAs. We observed a positive association between industrial TFAs and colon cancer (OR for highest vs lowest quartile [ORQ4vsQ1] = 1.28, 95% confidence interval 1.07-1.54). A higher association was observed between industrial TFAs and CRC, occurring after 50 years of age. In addition, elaidic acid was associated with an increased risk of colon (ORQ4vsQ1 = 1.58, 1.24-2.02) and specifically of proximal colon cancer (OR Q4vsQ1 = 2.12, 1.40-3.20), as well as of rectum cancer (ORQ4vsQ1 = 1.40, 1.07-1.83). An inverse association was observed between ruminant TFAs intake and colon cancer risk (ORQ4vsQ1 = 0.80, 0.67-0.97). Industrial TFAs, such as semisolid/solid hydrogenated oils, may increase the risk of CRC, especially colon and proximal colon cancer. In contrast, ruminant TFAs do not appear to be associated with CRC. Awareness programs and regulatory actions regarding hydrogenated oils are warranted, given their high consumption through ultra-processed foods in more developed and less developed countries.

National surveillance of cancer survival in Iran (IRANCANSURV): Analysis of data of 15 cancer sites from nine population-based cancer registries.

Cancer survival is a key indicator for the national cancer control programs. However, survival data in the East Mediterranean region (EMR) are limited. We designed a national cancer survival study based on population-based cancer registries (PBCRs) from nine provinces in Iran. The current study reports 5-year net survival of 15 cancers in Iranian adults (15-99 years) during 2014 to 2015 in nine provinces of Iran. We used data linkages between the cancer registries and the causes of death registry and vital statistics and active follow-up approaches to ascertain the vital status of the patients. Five-year net survival was estimated through the relative survival analysis. We applied the international cancer survival standard weights for age standardization. Five-year survival was highest for prostate cancer (74.9%, 95% CI 73.0, 76.8), followed by breast (74.4%, 95% CI 72.50, 76.3), bladder (70.4%, 95% CI 69.0, 71.8) and cervix (65.2%, 95% CI 60.5, 69.6). Survival was below 25% for cancers of the pancreas, lung, liver, stomach and esophagus. Iranian cancer patients experience a relatively poor prognosis as compared to those in high-income countries. Implementation of early detection programs and improving the quality of care are required to improve the cancer survival among Iranian patients. Further studies are needed to monitor the outcomes of cancer patients in Iran and other EMR countries.

Human Papillomavirus and Risk of Head and Neck Squamous Cell Carcinoma in Iran.

Human papillomavirus (HPV) causes a subset of head and neck squamous cell carcinoma (HNSCC). Knowledge of determinants of α-, ß-, and γ-HPVs types in the oral cavity is required for a better understanding of HNSCC development. Oral rinse samples of 498 HNSCC cases and 242 controls from the IROPICAN study-a large multicenter case-control study in Iran-were screened for 21 α-HPV, 46 ß-HPVs, and 52 γ-HPVs using bead-based HPV genotyping assays. α-HPVs were detected only in 1.2% of the patients and 2.9% of the controls from which HPV16 was the most prevalent type among participants. ß-HPVs were detected in 43.8% of the patients and 38.6% of the controls where the lip and oral cavity (45.5%) had the highest positivity. Values for γ-HPV prevalence in patients and controls were 26.1% and 24.7%, respectively. The highest percentage of γ-HPV positivity was found in the larynx (30.4%). Concerning the ß genus, HPV23 and HPV38 were the most prevalent types among the patients and controls, respectively. For the γ genus, SD2 in cases and HPV134 in controls were the most prevalent types. Overall, detection of α-HPVs (aOR, 0.40; 95% CI = 0.1 to 1.2; P = 0.11), ß-HPVs (aOR, 1.9; 95% CI = 0.9 to 1.6; P = 0.29), and γ-HPVs infections (aOR, 1.04; 95% CI = 0.7 to 1.5; P = 0.83) was not associated with the HNSCC development. Our data did not suggest an HPV-related etiology for HNSCC pathogenesis. Nonetheless, this study provides novel insights into the diversity of ß-, and γ-HPVs in different HNSCC anatomical subsites. IMPORTANCE Infection with human papillomavirus (HPV) is responsible for a subset of neck squamous cell carcinoma (HNSCC), but knowledge of the prevalence of and risk factors for oral HPV infection, especially cutaneous types in Iran, remains unknown. In a large retrospective study, the authors used a sensitive assay for the detection of α-, ß-, and γ-HPVs in oral rinse samples of HNSCC and matched controls. They find that the α-HPV contribution to HNSCC in Iran is lower than global prevalence. High-risk α-HPVs or cutaneous ß- and γ-HPVs were not associated with the HNSCC development. Besides, this study provides novel insights into the diversity of ß- and γ-HPVs in different HNSCC anatomical subsites.

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.

Dietary carbohydrate quality and risk of breast cancer among women.

BACKGROUND: A few studies have examined the relationship between carbohydrate quality index (CQI) and risk of breast cancer (BC) among women in Middle Eastern countries. We studied the associations between carbohydrate quality index and the risk of BC in overall and by menopausal status. METHODS: In this case-control study, dietary intake of 461 women with pathologically confirmed BC within the past year were examined. The same information were collected for 495 apparently healthy controls using a 168-item validated FFQ. Carbohydrate quality was determined by considering four criteria including: ratio of solid carbohydrates to total carbohydrates, dietary fiber intake, GI and the ratio of whole grains to total grains. RESULTS: Mean GI and GL of participants were totally 57.5 ± 7.2 and 245.7 ± 64.7, respectively. A trend toward significant association was seen between GI and odds of BC in the whole population; such that after stratifying analysis by menopausal status, premenopausal women in the highest quartile of GI were 1.85 times higher likely to have BC than those in the lowest quartile (95% CI: 1.12, 3.07, P = 0.01). We found that women with the greatest CQI had lower odds for BC, compared with those with the lowest CQI (0.63; 95% CI: 0.43-0.94, P = 0.03). This association was remained after stratifying analysis by menopausal status in premenopausal (0.55; 95% CI: 0.34-0.90, P = 0.04). CONCLUSION: We found that GI was directly and CQI inversely associated with odds of BC. In order to determine the effects of dietary carbohydrate quality prospective cohort studies are needed.

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.

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.

The Iranian Study of Opium and Cancer (IROPICAN): Rationale, Design, and Initial Findings.

BACKGROUND: The International Agency for Research on Cancer (IARC) recently classified opium use as a Group 1 carcinogen. However, much remains to be studied on the relation between opium and cancer. We designed the Iranian Opium and Cancer (IROPICAN) study to further investigate the association of opium use and cancers of the head and neck, bladder, lung, and colon and rectum. In this paper, we describe the rationale, design, and some initial results of the IROPICAN Study. METHODS: The IROPICAN is a multi-center case-control study conducted in 10 provinces of Iran. The cases were all histologically confirmed and the controls were selected from hospital visitors who were free of cancer, were not family members or friends of the cancer patients, and were visiting the hospital for reasons other than their own ailment. The questionnaires included detailed questions on opium use (including age at initiation, duration, frequency, typical amount, and route), and potential confounders, such as tobacco use (e.g., cigarettes, nass and water-pipe), and dietary factors. Biological samples, including blood and saliva, were also collected. RESULTS: The validation and pilot phases showed reasonably good validity, with sensitivities of 70% and 69% for the cases and controls, respectively, in reporting opium use. The results also showed excellent reliability, with intra-class correlation coefficients of 0.96 for ever opium use and 0.88 (95% CI: 0.80, 0.92) for regular opium use. In the main phase, we recruited 3299 cancer cases (99% response rate) and 3477 hospital visitor controls (89% response rate). The proportion of ever-use of opium was 40% among cases and 18% among controls. CONCLUSION: The IROPICAN study will serve as a major resource in studies addressing the effect of opium on risk of cancers of the head and neck, bladder, lung, and colon and rectum.

Adherence to plant-based dietary pattern and risk of breast cancer among Iranian women.

OBJECTIVES: Previous studies assessed the link between plant based diet and breast cancer risk rather than healthy and unhealthy plant based diet. This study examined the relation between plant-based dietary pattern and risk of breast cancer among Iranian women. METHODS: This hospital-based case-control study was conducted among 412 women with pathologically confirmed breast cancer within the past year and 456 apparently healthy controls. Dietary data were collected using a validated and reliable 168-item FFQ. We created three patterns including overall plant-based diet index (PDI), a healthful plant-based diet index (hPDI), and an unhealthful plant-based diet index (uPDI). The risk of breast cancer was compared across quartiles of PDI, hPDI, and uPDI. RESULTS: we did not find significant association between adherence to PDI and uPDI score and odds of breast cancer among women. However, a greater score of hPDI was inversely associated to the risk of breast cancer (OR: 0.63; 95% CI: 0.43-0.93, P = 0.01), in the crude model. After adjustment for age and energy, we saw stronger association between breast cancer risk and higher hPDI score (OR: 0.55; 95% CI: 0.37-0.82, P = 0.002). After stratified by menopausal status, we did not find significant association between PDI and uPDI score and risk of breast cancer. However, pre- and postmenopausal women in the highest quartile of hPDI score had lower risk of breast cancer than those in the lowest quartile. CONCLUSIONS: we found an inverse significant association between hPDI and odds of breast cancer in the whole population of study. After stratifying by menopausal status, this correlation was also seen both in pre and postmenopausal women.