Seroprevalence of SARS-CoV-2 antibody among urban Iranian population: findings from the second large population-based cross-sectional study.

BACKGROUND: The first large serosurvey in Iran found a SARS-CoV-2 antibody seroprevalence of 17.1% among the general population in the first wave of the epidemic by April, 2020. The purpose of the current study was to assess the seroprevalence of COVID-19 infection among Iranian general population after the third wave of the disease. METHODS: This population-based cross-sectional study was conducted on 7411 individuals aged ≥10 years old in 16 cities across 15 provinces in Iran between January and March, 2021. We randomly sampled individuals registered in the Iranian electronic health record system based on their national identification numbers and invited them by telephone to a healthcare center for data collection. Presence of SARS-CoV-2-specific IgG and IgM antibodies was assessed using the SARS-CoV-2 ELISA kits. The participants were also asked about their recent COVID-19-related symptoms, including cough, fever, chills, sore throat, headache, dyspnea, diarrhea, anosmia, conjunctivitis, weakness, myalgia, arthralgia, altered level of consciousness, and chest pain. The seroprevalence was estimated after adjustment for population weighting and test performance. RESULTS: The overall population-weighted seroprevalence adjusted for test performance was 34.2% (95% CI 31.0-37.3), with an estimated 7,667,874 (95% CI 6,950,412-8,362,915) infected individuals from the 16 cities. The seroprevalence varied between the cities, from the highest estimate in Tabriz (39.2% [95% CI 33.0-45.5]) to the lowest estimate in Kerman (16.0% [95% CI 10.7-21.4]). In the 16 cities studied, 50.9% of the seropositive individuals did not report a history of symptoms suggestive of COVID-19, implying an estimation of 3,902,948 (95% CI 3,537,760-4,256,724) asymptomatic infected individuals. CONCLUSIONS: Nearly one in three individuals were exposed to SARS-CoV-2 in the studied cities by March 2021. The seroprevalence increased about two-fold between April, 2020, and March, 2021.

Cancer in Iran 2008 to 2025: Recent incidence trends and short-term predictions of the future burden.

Policymakers require estimates of the future number of cancer patients in order to allocate finite resources to cancer prevention, treatment and palliative care. We examine recent cancer incidence trends in Iran and present predicted incidence rates and new cases for the entire country for the year 2025. We developed a method for approximating population-based incidence from the pathology-based data series available nationally for the years 2008 to 2013, and augmented this with data from the Iranian National Population-based Cancer Registry (INPCR) for the years 2014 to 2016. We fitted time-linear age-period models to the recent incidence trends to quantify the future cancer incidence burden to the year 2025, delineating the contribution of changes due to risk and those due to demographic change. The number of new cancer cases is predicted to increase in Iran from 112 000 recorded cases in 2016 to an estimated 160 000 in 2025, a 42.6% increase, of which 13.9% and 28.7% were attributed to changes in risk and population structure, respectively. In terms of specific cancers, the greatest increases in cases are predicted for thyroid (113.8%), prostate (66.7%), female breast (63.0%) and colorectal cancer (54.1%). Breast, colorectal and stomach cancers were the most common cancers in Iran in 2016 and are predicted to remain the leading cancers nationally in 2025. The increasing trends in incidence of most common cancers in Iran reinforce the need for the tailored design and implementation of effective national cancer control programs across the country.

Assessment of hydrogeochemical characteristics and quality of groundwater resources in relation to risk of gastric cancer: comparative analysis of high- and low-risk areas in Iran.

The chemical quality of groundwater supplies in two high-risk area (HRA) and low-risk area (LRA) for gastric cancer in Iran was assessed through hydrogeochemical analysis and water quality indices. For this aim, Piper and Schoeller diagrams and water quality index (WQI) were applied. In addition, exposure to nitrate via drinking water and its corresponding risk were also assessed using Monte Carlo simulation technique. Data on physicochemical properties of groundwater resources were obtained from Iran Water Resources Management Company. Sampling and analysis of tap water for nitrate concentration were conducted in two cities of Shiraz (as a representative of LRA) and Ardabil (as a representative of HRA). According to Piper diagrams, the dominant hydrogeochemical facies of groundwater supplies in HRA and LRA were Na-HCO3 (43.75%) and Ca-HCO3 (41.77%), respectively. The predominant cations in groundwater resources of HRA were found to be Na+ (68.06%) and Ca2+ (31.94%). For LRA, the typical cations were in decreasing trend: Ca2+ (39.64%) > Mg2+ (18.35%) > Na+ (17.26%). For two areas, HCO3-, SO42- and Cl- were, respectively, the most frequent anions. Two-sample Wilcoxon test showed that there were statistically significant difference between two areas in terms of anions and cations concentrations (p value < 0.05). The mean of total hardness (Ca2+ + Mg2+) concentration of water supplies in LRA (528.1 mg/L) was higher than HRA (263.1 mg/L), whereas the mean of Na+ concentration was found to be lower in LRA (90.6 mg/L) compared with HRA (108.1 mg/L). The sum of nitrate intake and its risk in LRA was higher than HRA. WQI results showed that drinking water quality in HRA and LRA ranged from excellent to poor and most water resources were of a good quality class. Further studies are suggested to investigate the role of drinking water in the etiology of gastric cancer in Iran.

Neglected role of hookah and opium in gastric carcinogenesis: a cohort study on risk factors and attributable fractions.

A recent study showed an association between hookah/opium use and gastric cancer but no study has investigated the relationship with gastric precancerous lesions. We examined the association between hookah/opium and gastric precancerous lesions and subsequent gastric cancer. In a population-based cohort study, 928 randomly selected, healthy, Helicobacter pylori-infected subjects in Ardabil Province, Iran, were followed for 10 years. The association between baseline precancerous lesions and lifestyle risk factors (including hookah/opium) was analyzed using logistic regression and presented as odds ratios (ORs) and 95% confidence intervals (CIs). We also calculated hazard ratios (HRs) and 95% CIs for the associations of lifestyle risk factors and endoscopic and histological parameters with incident gastric cancers using Cox regression models. Additionally, the proportion of cancers attributable to modifiable risk factors was calculated. During 9,096 person-years of follow-up, 36 new cases of gastric cancer were observed (incidence rate: 3.96/1,000 persons-years). Opium consumption was strongly associated with baseline antral (OR: 3.2; 95% CI: 1.2-9.1) and body intestinal metaplasia (OR: 7.3; 95% CI: 2.5-21.5). Opium (HR: 3.2; 95% CI: 1.4-7.7), hookah (HR: 3.4; 95% CI: 1.7-7.1) and cigarette use (HR: 3.2; 95% CI: 1.4-7.5), as well as high salt intake, family history of gastric cancer, gastric ulcer and histological atrophic gastritis and intestinal metaplasia of body were associated with higher risk of gastric cancer. The fraction of cancers attributable jointly to high salt, low fruit intake, smoking (including hookah) and opium was 93% (95% CI: 83-98). Hookah and opium use are risk factors for gastric cancer as well as for precancerous lesions. Hookah, opium, cigarette and high salt intake are important modifiable risk factors in this high-incidence gastric cancer area.

Consumption of non-antibacterial drugs may have negative impact on Helicobacter pylori colonization in the stomach.

Background: Nineteen non-antibacterials were examined to show that their consumption for treatment of other diseases may inhibit Helicobacter pylori. Four antibiotics were used for comparison. Materials and methods: Agar dilution method was used to examine the susceptibility of 20 H. pylori isolates to 4 antibiotics; metronidazole (MTZ), clarithromycin (CLR), amoxicillin (AMX), tetracycline (TET) and 19 non-antibacterials; proton pump inhibitors (PPIs), H2-blockers, bismuth subsalicylate (BSS), antifungals, statins, acetaminophen (ACE), aspirin (ASA), B-vitamins (B-Vits; Vit B1, Vit B6 and Vit Bcomplex) and vitamin C (Vit C). Blood agar plates were prepared with different concentrations of drugs and spot-inoculated with bacterial suspensions. Plates were incubated at 37 °C under microaerobic conditions and examined after 3-5 days. The isolate #20 that was mucoid and resistant to 19 drugs, including MTZ and SMV was tested against combined MTZ (8 µg/mL) and SMV (100 µg/mL). Results were analyzed statistically. Results: Minimum inhibitory concentrations (MICs, µg/mL) of drugs and the frequency of susceptible H. pylori were determined as MTZ (8, 80%), CLR (2, 90%), AMX (1, 100%), TET (0.5, 70%), PPIs (8-128, 80%), H2-blockers (2000-8000, 75-80%), BSS (15, 85%), antifungals (64-256, 30-80%), statins (100-250, 35-90%), ACE (40, 75%), ASA (800, 75%), B-Vits (5000-20000, 80-100%) and Vit C (2048, 85%). Susceptibility of H. pylori isolates to 16 out of 19 non-antimicrobials (75-100%) was almost similar to those of antibiotics (70-100%) (P-value >0.05). The highest susceptibility rate (100%) belonged to Vit B1, Vit B6 and AMX. Out of 20 H. pylori isolates, 17 (85%) were susceptible to ≥13 non-antimicrobials and 3 (15%) were susceptible to < 13 (P-value <0.05). Mucoid H. pylori showed susceptibility to combination of MTZ and SMV. Conclusions: Most of non-antibacterials inhibited H. pylori isolates, similar to antibiotics but their MICs exceeded those of antibiotics and their plasma concentrations. At low plasma concentration, non-antimicrobials may act as weak antibacterials, antibiotic adjuvants and immunostimulators.

The contribution of metabolic risk factors to cardiovascular mortality in Golestan cohort study: Population attributable fraction estimation.

Background: Cardiovascular diseases (CVDs) are the leading causes of global mortality and disability. Several studies demonstrated that metabolic risk factors increase cardiovascular mortality. The aim of this study is to examine CVDs deaths and population attributable fractions (PAFs) of their metabolic risk factors in Iran. Methods: This is a study on 8621 participants aged 45-75 years and older, recruited in the repeated measurement phase of the Golestan cohort study (GCS) in northeast of Iran. The Cox proportional hazards model was used to determine the adjusted hazard ratios (HRs). PAFs were calculated to enumerate CVDs mortality avoidable in the population if metabolic risk factors were eliminated. Results: The mortality of CVDs was attributable to metabolic factors, including high waist circumference (PAF, 28 %, [95 % CI: 16%-38 %]), high fasting blood sugar (FBS) (20 %, [15%-24 %]), overweight and obesity (19 %, [8%-28 %]), high blood pressure (16 %, [11%-21 %]), high low-density lipoprotein cholesterol (LDL-C) (8 %, [1%-15 %]), and high triglyceride (TG) (7 %, [3%-11 %]). Collectively, these metabolic risk factors accounted for 50 % of CVDs deaths. Females (67 %, [50%-78 %]) had a higher joint PAF of metabolic risk factors compared to males (43 %, [27%-55 %]). Conclusions: The pattern of CVDs mortality attributable to metabolic risk factors in this study is not the same as similar studies in other parts of the world and previous studies in Iran. It is imperative that CVDs risk factors be specifically evaluated and addressed in various populations due to variety in geographical and temporal patterns in contribution of metabolic risk factors to CVD mortality.

Effectiveness of long-term low-dose aspirin in the prevention of gastric cancer after Helicobacter pylori eradication: study design and rationale of Ardabil gastric cancer randomized placebo-controlled prevention trial (AGCPT).

BACKGROUND: In addition to Helicobacter pylori (H. pylori) infection eradication, some medications, including aspirin, metformin, and statins, have been suggested to have protective effects against gastric cancer (GC) development in observational studies. We launched the Ardabil gastric cancer randomized placebo-controlled prevention trial (AGCPT) to evaluate the effectiveness of long-term low-dose aspirin use for the prevention of development and mortality of GC after H. pylori eradication. METHODS/DESIGN: AGCPT is a prospective population-based double-blind, randomized clinical trial. The study sample was targeted at 21,000 participants aged from 35 to 70 years old, both sexes, in Ardabil, a province in northwest Iran with relatively high rates of GC incidence and mortality. All eligible participants were initially tested for H. pylori infection using a H. pylori stool antigen test. Participants with positive tests undergo H. pylori eradication by standard treatment regimens. All participants with a negative test and those with a positive test with a subsequent confirmed H. pylori eradication test were entered into the intervention phase. In the intervention phase, participants were allocated randomly into either the treatment (daily oral consumption of 81 mg enteric-coated aspirin tablets) arm or the control (placebo) arm using permuted balanced blocks. Subjects will be followed for an average period of 10 years to evaluate the incidence and mortality rates of GC. DISCUSSION: In addition to preventing other diseases like cardiovascular events, aspirin may prevent GC incidence and mortality. AGCPT will investigate the difference between the two study arms in the proportion of the cumulative incidence and mortality rates of GC. The study's results may help policymakers and researchers update the strategies for GC prevention. TRIAL REGISTRATION: This trial with the registry name of "The effect of Low-dose Aspirin in the Prevention of Gastric Cancer" was registered in the Iranian Registry of Clinical Trials, IRCT.ir, under the identifier IRCT201105082032N3. Registered on April 21, 2017.

An Efficient and Easy- to- Use Method for Extraction of H. pylori DNA from Archival Formalin-Fixed and Paraffin-Embedded Gastric Tissues.

Background & Objective: Formalin-fixed paraffin-embedded archived tissues are useful for the genetic analyses and assessment of some patients' disease history, including infectious diseases. However, there is no established protocol for extracting bacterial DNA from the archived specimens. In this study DNA was extracted from the archived H. pylori-positive gastric biopsies by some modifications applied to the previously published protocols. The quality of the extracted DNA was assessed by amplifying H. pylori-specific 16S rRNA gene. Methods: Fifty H. pylori-positive gastric biopsies obtained, fixed, and embedded in paraffin blocks during 2002-2008 were recruited. After paraffin removal, simultaneous proteinase K treatment and mechanical disruption using glass beads were used for the digestion of gastric tissues. DNA extraction was performed by adding one step of phenol treatment and two steps of incubation to the conventional phenol-chloroform method. The quantity and quality of the extracted DNA samples were assessed. Also, PCR was performed using primers specific for the H. pylori-specific 16S rRNA. Results: The electrophoresis showed that intact DNAs were recovered from all biopsy samples. Amplification of the PCR products with the size of 519bp confirmed the presence of H. pylori-specific 16S rRNA gene in all the biopsies. Conclusion: A 100% success rate for the amplification of H. pylori-specific 16S rRNA gene was achieved from all the samples. In this regard, the designed modified method resulted in the effective removal of interfering contaminations and enhanced the quality of the extracted bacterial DNA from the archived tissues. These modifications may contribute to better extraction of the intact DNA from different bacteria present in human tissues.

Modeling Epidemiology Data with Machine Learning Technique to Detect Risk Factors for Gastric Cancer.

PURPOSE: Gastric cancer (GC) ranks as the 7th most common cancer worldwide and a leading cause of cancer mortality. In Iran, stomach malignancies are the most common fatal cancers with higher than world average incidence. In recent years, methods like machine learning that provide the opportunity of merging health issues with computational power and learning capacity have caught considerable attention for prediction and diagnosis of diseases. In this study, we aimed to model GC data to find risk factors and identify GC cases in Golestan Cohort Study (GCS), using gradient boosting as a machine learning technique. METHODS: Since the GC class (280) was smaller than not-GC (49,467), "Synthetic Minority Oversampling Technique" was used to balance the dataset. Seventy percent of the data was used to train the gradient boosting algorithm and find effective factors on gastric cancer, and the remaining 30% was used for accuracy assessment. RESULTS: Our results indicated that out of 19 factors, age, social economical status, tea temperature, body mass index, gender, and education were the top six effective factors with impact rates of 0.24, 0.16, 0.13, 0.13, and 0.07, respectively. The trained model classified 70 out of 72 GC patients in the test set, correctly. CONCLUSION: The results indicate that this model can effectively detect gastric cancer (GC) by utilizing important risk factors, thus avoiding the need for invasive procedures. The model's performance is reliable when provided with an adequate amount of input data, and as the dataset expands, its accuracy and generalization improve significantly. Overall, the trained system's success stems from its ability to identify risk factors and identify cancer patients.

Incident cancers attributable to using opium and smoking cigarettes in the Golestan cohort study.

Background: Opium consumption has recently been identified as a carcinogen, but the impact of opium use on cancer burden is unknown. We aimed to evaluate the fraction of cancers that could be attributed to opium use alone and in combination with cigarette smoking in a region where opium is widely used. Methods: 50,045 Iranian adults were recruited to this prospective cohort study between 2004 and 2008 and were followed through January 2022. We assessed the association between using opium and/or cigarette smoking and various cancers using proportional hazards regression models. We then calculated population attributable fractions (PAFs) for all cancers and for groups of cancers causally linked to opium and cigarette smoking. Findings: Of the total participants, 8% only used opium, 8.3% only smoked cigarettes, and 9% used both substances. During a median 14 years of follow-up, 2195 individuals were diagnosed with cancer, including 215 opium-related cancers (lung, larynx, and bladder) and 1609 tobacco-related cancers (20 types). Opium use alone was estimated to cause 35% (95% CI: 26%-45%) of opium-related cancers, while smoking cigarettes alone was estimated to cause 9% (6%-12%) of tobacco-related cancers in this population. Using opium and/or cigarettes was estimated to cause 13% (9%-16%) of all cancers, 58% (49%-66%) of opium-related cancers, and 15% (11%-18%) of tobacco-related cancers. Moreover, joint exposure to opium and cigarettes had the greatest impact on cancers of the larynx, pharynx, lung, and bladder, with PAFs ranging from 50% to 77%. Interpretation: Using opium and smoking cigarettes account for a large proportion of cancers in this population. To reduce the cancer burden, prevention policies should aim to decrease the use of both substances through public awareness campaigns and interventional efforts. Funding: The Golestan Cohort Study work was funded by the Tehran University of Medical Sciences, Cancer Research UK, U.S. National Cancer Institute, International Agency for Research on Cancer. The presented analysis was supported by the International HundredK+ Cohorts Consortium (IHCC).

A Population-Based Cross-sectional Study on the Prevalence and Associated Risk Factors of Helicobacter pylori Infection in Rafsanjan, a Low Gastric Cancer Area in Southeast Iran.

Background: Despite all improvements in sanitation and exposure to antibiotics over time, Helicobacter pylori (HP) prevalence remains high, affecting the lives of about half of the world population, which can gradually lead to serious upper gastrointestinal disorders. Understanding HP's epidemiologic patterns help us to better manage the burden of this infection and to plan more effectively regarding potential screening or eradication strategies. We, therefore, aimed to report the crude and age- and sex-standardized prevalence rate of HP infection, its trend, and possible associated factors among asymptomatic healthy individuals in Rafsanjan city, a low-incidence area of gastric cancer (GC) in the southeast of Iran, from July 2018 to December 2021. Methods: This population-based cross-sectional descriptive study included 2,046 male and female subjects between 3 to 72 years who were in good health condition. Study participants were randomly selected from the Health Houses and each underwent a questionnaire-based interview and provided blood and feces samples. The presence of HP infection was detected by serum IgG antibodies and stool antigen test. Results: The overall and age- and sex-standardized prevalence rates of HP infection were 50.9% and 43%, respectively. The prevalence rate has notably decreased in all age groups compared with 2007. Also, it was significantly higher among men (P=0.033) and increased with advancing age (P<0.001). A higher population density living in a specific room area (P=0.012) increased the likelihood of HP infection. Conclusion: To conclude, the prevalence of HP infection is decreasing over time in Rafsanjan city, which may be due to improvements in living standards in this area. A healthy lifestyle and adherence to hygienic principles, especially during childhood, may be required for a reduction in the prevalence of HP infection.

Multimorbidity and associations with clinical outcomes in a middle-aged population in Iran: a longitudinal cohort study.

BACKGROUND: As the populations of lower-income and middle-income countries age, multimorbidity is increasing, but there is little information on its long-term consequences. We aimed to show associations between multimorbidity and outcomes of mortality and hospitalisation in Iran, a middle-income country undergoing rapid economic transition. METHODS: We conducted a secondary analysis of longitudinal data collected in the Golestan Cohort Study. Data on demographics, morbidities and lifestyle factors were collected at baseline, and information on hospitalisations or deaths was captured annually. Logistic regression was used to analyse the association between baseline multimorbidity and 10-year mortality, Cox-proportional hazard models to measure lifetime risk of mortality and zero-inflation models to investigate the association between hospitalisation and multimorbidity. Multimorbidity was classified as ≥2 conditions or number of conditions. Demographic, lifestyle and socioeconomic variables were included as covariables. RESULTS: The study recruited 50 045 participants aged 40-75 years between 2004 and 2008, 47 883 were available for analysis, 416 (57.3%) were female and 12 736 (27.94%) were multimorbid. The odds of dying at 10 years for multimorbidity defined as ≥2 conditions was 1.99 (95% CI 1.86 to 2.12, p<0.001), and it increased with increasing number of conditions (OR of 3.57; 95% CI 3.12 to 4.08, p<0.001 for ≥4 conditions). The survival analysis showed the hazard of death for those with ≥4 conditions was 3.06 (95% CI 2.74 to 3.43, p<0.001). The number of hospital admissions increased with number of conditions (OR of not being hospitalised of 0.36; 95% CI 0.31 to 0.52, p<0.001, for ≥4 conditions). CONCLUSION: The long-terms effects of multimorbidity on mortality and hospitalisation are similar in this population to those seen in high-income countries.

Prevalence of overweight and obesity in Iranian population: A population-based study in northwestern of Iran.

BACKGROUND: Overweight and obesity and its problems are the most important health and nutrition issues of adolescents in developed and developing countries. This study aimed to determine the prevalence of overweight and obesity among the studied population. DESIGN AND METHODS: This Persian Cohort Study is a population-based study of 10,000 men and women, aged 35-70 years in northwest of Iran. Anthropometric parameters such as height, weight, waist circumference and hip circumference were measured by interviewers. Body Mass Index (BMI) and waist-to-hip ratio (WHR) were used to assess overweight and obesity. RESULTS: The mean age of all participants was 49.1±8.7 and 56.1% of them were female.  The mean height of participants was 162.5±9.4 kg in range 126-196 and the mean weight of them was 78.5±13.1 cm in range 40-164. According to BMI, 42.7% of all participants had overweight and 45% had obesity. According to the WHR, 71.8% of males and 97.9% of females had high WHR (abdominal obesity). CONCLUSIONS: Results showed that the rate of overweight and obesity in studied people was more than country rate. So programing for raising their Quality of Life (QoL) and lifestyle and also changing their poor nutritional habits is essential in area healthy people.

Gastric Cancer in Iran: An Overview of Risk Factors and Preventive Measures.

Despite all recent treatment advances and the worldwide decline in the incidence rate, gastric cancer (GC) remains an ongoing global health challenge and one of the major leading causes of cancer-specific deaths, particularly in high-incidence regions including Iran. Since GC is often diagnosed in advanced stages, the best action may be to enable early diagnosis of the disease or even prevent it in the first place through identification and control of the underlying risk factors. Endoscopy, as the gold standard method, is both expensive and invasive, making it an unfavorable device in this regard. Therefore, it is crucial to implement a reliable region-specific screening and surveillance program to identify high-risk individuals with more efficient screening modalities. Here, in addition to a review of current GC knowledge, we presented the data of newly-established Population-based Cancer Registries (PBCRs) in Iran. Our assessment confirmed earlier reports of a very high GC incidence rate in the northwestern and northern provinces of Iran, most notably Ardabil. Along with the important role of conventional risk factors such as Helicobacter pylori (HP) infection and high dietary intake of salt, of more interest, we highlighted new region-specific risk factors, namely hookah, and opium. In conclusion, it seems the best results in reducing GC incidence and mortality rates on larger scales arise from modifying behavioral and environmental risk factors and advancing genetic and molecular biomarkers in order to supersede endoscopy. Regular endoscopic screening and antibiotic chemoprophylaxis against HP are still more appropriate in high-risk groups with specified criteria.

The marginal causal effect of opium consumption on the upper gastrointestinal cancer death using parametric g-formula: An analysis of 49,946 cases in the Golestan Cohort Study, Iran.

Upper gastrointestinal (UGI) cancer, including esophageal and gastric, is one of the most common cancers in the world. Hence, the determination of risk factors of UGI helps to reduce the economic and social burden of this cancer in communities. In Iran, the consumption of opium because of its neighborhood with Afghanistan are considerable. In this study, we examine the causal effect of opium use on the time to UGI cancer death. Based on the Golestan Cohort Study (GCS) in northeastern of Iran, about 50000 adults were enrolled to the study for four years (2004-2008) and followed annually until July 2018. We used "parametric g-formula" to study the causal effect of opium use on the time to death due to UGI. In this study, the information of 49946 individuals due to missingness were analyzed. So the median of follow-up time was 144 months and the prevalence of opium use was 17% (about 8489 persons). During the follow-up period, 593 (1.2%) death from upper gastrointestinal cancer were reported. The study showed that the effect of opium use on the time to UGI death was statistically significant (adjusted risk-ratio based on parametric g-formula = 1.31, 95% CI: [1.04, 1.65]). Additionally, the Population Attributable Fraction (PAF) in UGI cancer deaths of opium use was estimated 5.3% (95% CI: [0.6%, 11.3%]). Our results showed a causal effect of opium use on the intensity of upper gastrointestinal cancer death.

SARS-CoV-2 antibody seroprevalence in the general population and high-risk occupational groups across 18 cities in Iran: a population-based cross-sectional study.

BACKGROUND: Rapid increases in cases of COVID-19 were observed in multiple cities in Iran towards the start of the pandemic. However, the true infection rate remains unknown. We aimed to assess the seroprevalence of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 18 cities of Iran as an indicator of the infection rate. METHODS: In this population-based cross-sectional study, we randomly selected and invited study participants from the general population (from lists of people registered with the Iranian electronic health record system or health-care centres) and a high-risk population of individuals likely to have close social contact with SARS-CoV-2-infected individuals through their occupation (from employee lists provided by relevant agencies or companies, such as supermarket chains) across 18 cities in 17 Iranian provinces. Participants were asked questions on their demographic characteristics, medical history, recent COVID-19-related symptoms, and COVID-19-related exposures. Iran Food and Drug Administration-approved Pishtaz Teb SARS-CoV-2 ELISA kits were used to detect SARS-CoV-2-specific IgG and IgM antibodies in blood samples from participants. Seroprevalence was estimated on the basis of ELISA test results and adjusted for population weighting (by age, sex, and city population size) and test performance (according to our independent validation of sensitivity and specificity). FINDINGS: From 9181 individuals who were initially contacted between April 17 and June 2, 2020, 243 individuals refused to provide blood samples and 36 did not provide demographic information and were excluded from the analysis. Among the 8902 individuals included in the analysis, 5372 had occupations with a high risk of exposure to SARS-CoV-2 and 3530 were recruited from the general population. The overall population weight-adjusted and test performance-adjusted prevalence of antibody seropositivity in the general population was 17·1% (95% CI 14·6-19·5), implying that 4 265 542 (95% CI 3 659 043-4 887 078) individuals from the 18 cities included were infected by the end of April, 2020. The adjusted seroprevalence of SARS-CoV-2-specific antibodies varied greatly by city, with the highest estimates found in Rasht (72·6% [53·9-92·8]) and Qom (58·5% [37·2-83·9]). The overall population weight-adjusted and test performance-adjusted seroprevalence in the high-risk population was 20·0% (18·5-21·7) and showed little variation between the occupations included. INTERPRETATIONS: Seroprevalence is likely to be much higher than the reported prevalence of COVID-19 based on confirmed COVID-19 cases in Iran. Despite high seroprevalence in a few cities, a large proportion of the population is still uninfected. The potential shortcomings of current public health policies should therefore be identified to prevent future epidemic waves in Iran. FUNDING: Iranian Ministry of Health and Medical Education. TRANSLATION: For the Farsi translation of the abstract see Supplementary Materials section.

Comparison of breast cancer survival in two populations: Ardabil, Iran and British Columbia, Canada.

BACKGROUND: Patterns in survival can provide information about the burden and severity of cancer, help uncover gaps in systemic policy and program delivery, and support the planning of enhanced cancer control systems. The aim of this paper is to describe the one-year survival rates for breast cancer in two populations using population-based cancer registries: Ardabil, Iran, and British Columbia (BC), Canada. METHODS: All newly diagnosed cases of female breast cancer were identified in the Ardabil cancer registry from 2003 to 2005 and the BC cancer registry for 2003. The International Classification of Disease for Oncology (ICDO) was used for coding cancer morphology and topography. Survival time was determined from cancer diagnosis to death. Age-specific one-year survival rates, relative survival rates and weighted standard errors were calculated using life-tables for each country. RESULTS: Breast cancer patients in BC had greater one-year survival rates than patients in Ardabil overall and for each age group under 60. CONCLUSION: These findings support the need for breast cancer screening programs (including regular clinical breast examinations and mammography), public education and awareness regarding early detection of breast cancer, and education of health care providers.

Environmental etiology of gastric cancer in Iran: a systematic review focusing on drinking water, soil, food, radiation, and geographical conditions.

The aim of this systematic review study was to investigate the causal relationship between environmental factors and gastric cancer (GC) in Iran. In a narrow definition, the environment includes water, soil, air, and food. This definition was the main criterion for the inclusion of articles in this study. In addition, exposure to radiation and geographical conditions were considered as less investigated environmental factors in the literatures. International (PubMed, Web of Science, ScienceDirect, Scopus, and Cochran) and national (Scientific Information Database) databases were searched for articles on GC and environmental risk factors in Iran. Twenty-six articles were found to meet the inclusion criteria after title, abstract, and full text review. Risk factors identified for GC include consumption of red meat; high fat, fried, and salted meat; smoked, salted, and fried foods; some dairy products; roasted and fried seeds; strong and hot tea; and un-piped and unchlorinated drinking water, as well as exposure to radiation, loess sediment, soft and grassy soil, soil containing low concentration of molybdenum, and proximity to volcanos. Fresh fruits and vegetable, fresh fish, and honey consumption were recognized as protective agents. Given the risk factors identified, strategies to prevent GC would be educating people to choose a healthy diet and to cook and store food properly, providing access to safe drinking water, taking into account topographical and geographical conditions in choosing a right location to build residential areas, and regulating the use of radiation-emitting devices.

Monitoring and exposure assessment of nitrate intake via fruits and vegetables in high and low risk areas for gastric cancer.

BACKGROUND: Gastric cancer (GC) is the first leading cause of cancer-related deaths in Iran. GC is a multifactorial disease and is caused by the interaction of genetic and environmental factors. The aim of this study was to assess the exposure and risk of nitrate intake through fruits and vegetables (F&V) in high-risk area (HRA) and low-risk area (LRA) of GC in Iran. METHODS: Twenty nine species of F&V were examined for nitrate by reverse-phase HPLC (RP-HPLC) method. Food frequency questionnaire (FFQ) data of 2000 adults participating in Persian cohort were applied to determine consumption patterns of F&V in those areas. A point-estimate daily intake was applied to compare two areas in terms of nitrate intake. Monte-Carlo simulation technique was applied to estimate chronic daily intake (CDI) of nitrate. RESULTS: The results showed that point-estimate daily intake of nitrate for subjects participated in the study was 2.02 ± 1.02 mg kg-1 day-1 in HRA and 1.98 ± 1.05 mg kg-1 day-1 in LRA. 6.53% of the participants in the HRA, and 5.9% of the participants in the LRA had an unacceptable point-estimate daily intake compared with an acceptable limit of 3.7 mg kg-1 day-1 established by FAO/WHO. CDI of nitrate in HRA was 1.94 ± 0.95 mg kg-1 day-1 and in the LRA was 1.93 ± 1.06 mg kg-1 day-1. CONCLUSION: The results showed that there is no difference between HRA and LRA in terms of nitrate intake through F&V.

Cancer incidence in Iran in 2014: Results of the Iranian National Population-based Cancer Registry.

BACKGROUND: We aimed to report, for the first time, the results of the Iranian National Population-based Cancer Registry (INPCR) for the year 2014. METHODS: Total population of Iran in 2014 was 76,639,000. The INPCR covered 30 out of 31 provinces (98% of total population). It registered only cases diagnosed with malignant new primary tumors. The main sources for data collection included pathology center, hospitals as well as death registries. Quality assessment and analysis of data were performed by CanReg-5 software. Age standardized incidence rates (ASR) (per 100,000) were reported at national and subnational levels. RESULTS: Overall, 112,131 new cancer cases were registered in INPCR in 2014, of which 60,469 (53.9%) were male. The diagnosis of cancer was made by microscopic confirmation in 76,568 cases (68.28%). The ASRs of all cancers were 177.44 and 141.18 in male and female, respectively. Cancers of the stomach (ASR = 21.24), prostate (18.41) and colorectum (16.57) were the most common cancers in men and the top three cancers in women were malignancies of breast (34.53), colorectum (11.86) and stomach (9.44). The ASR of cervix uteri cancer in women was 1.78. Our findings suggested high incidence of cancers of the esophagus, stomach and lung in North/ North West of Iran. CONCLUSION: Our results showed that Iran is a medium-risk area for incidence of cancers. We found differences in the most common cancers in Iran comparing to those reported for the World. Our results also suggested geographical diversities in incidence rates of cancers in different subdivisions of Iran.