Ecologic study of serum selenium and upper gastrointestinal cancers in Iran

Stomach, Esophageal, and Lung Cancer Mortality Risk and Their Shared Risk Factors in Iran: A County-Level Spatial Analysis

Background

Disease mapping has a long history in epidemiology. Evaluating the spatial pattern of several diseases, as well as shared and specific risk factors in mortality, is considered one of the applications of disease mapping. Stomach, esophageal, and lung cancers are among the five most common cancers among both genders in Iran. The present study aimed to investigate the geographical distribution of the relative risk of mortality and to define the spatial pattern of shared and specific risk factors for the three cancers mentioned above by sharing their mortality data at the province and county levels in Iran.

Methods

In this ecological study, the mortality data of stomach, esophageal, and lung cancers were analyzed in Iran from March 2013 to March 2015. The Besag, York, and Mollie's (BYM) and shared component (SC) models were used to compare the spatial variations of the relative risks of those cancers by applying OpenBUGS version 3.2.3 and R version 3.6.3.

Results

The number of deaths from esophageal, stomach, and lung cancers in Iran during March 2013-March 2014 was 11,720, of which stomach and lung cancers were 50% and 30%, respectively. In this period, stomach, esophageal, and lung cancer mortality rates were 9, 2, and 7 per 100,000 individuals, respectively. The spatial pattern of the stomach and esophageal cancer mortality was more similar to lung cancer due to the risk factors shared only between esophageal and stomach cancers. The relative risk for esophageal and stomach cancers was significantly higher in the northern half of Iran than in the southern half. However, the dispersion of the relative risk of lung cancer was higher than the other two cancers. The highest RR for esophageal, stomach, and lung cancers were in West Azerbaijan and East Azerbaijan provinces. The lowest relative risk for esophageal and stomach cancers was Hormozgan and for lung cancer was Ilam.

Conclusion

Some differences were observed in the achieved patterns of provinces and counties, the most significant factor of which was related to considering smaller areas. As indicated in this study, high-risk areas can be identified easier by analyzing and mapping the diseases on a smaller scale and more accurate, less expensive, and faster health policies, and plans can be adopted to identify and reduce the risk factors related to diseases.

Selenium May Be Involved in Esophageal Squamous Cancer Prevention by Affecting GPx3 and FABP1 Expression: A Case-Control Study Based on Bioinformatic Analysis

The role of selenium in the developmental process of esophageal cancer (EC) requires further investigation. To explore the relationship between selenium-related factors and EC through bioinformatic analysis, a case-control study was conducted to verify the results. Utilizing the GEPIA and TCGA databases, we delineated the differential expression of glutathione peroxidase 3 (GPx3) in EC and normal tissues, identified differentially expressed genes (DEGs), and a performed visualization analysis. Additionally, 100 pairs of dietary and plasma samples from esophageal precancerous lesions (EPLs) of esophageal squamous cancer (ESCC) cases and healthy controls from Huai'an district, Jiangsu, were screened. The levels of dietary selenium, plasma selenium, and related enzymes were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) or ELISA kits. The results showed lower GPx3 expression in tumor tissues compared to normal tissues. Further analysis revealed that DEGs were mainly involved in the fat digestion and absorption pathway, and the core protein fatty acid binding protein 1 (FABP1) was significantly upregulated and negatively correlated with GPx3 expression. Our case-control study found that selenium itself was not associated with EPLs risk. However, both the decreased concentration of GPx3 and the increase in FABP1 were positively correlated with the EPLs risk (p for trend = 0.035 and 0.046, respectively). The different expressions of GPx3 and FABP1 reflect the potential of selenium for preventing ESCC at the EPLs stage. GPx3 may affect EC through FABP1, which remains to be further studied.

Mineral Intake and Cardiovascular Disease, Cancer, and All-Cause Mortality: Findings from the Golestan Cohort Study

Associations between mineral intake and mortality in non-Western countries have not been studied adequately. This study evaluated these associations in the Golestan Cohort Study, featuring a Middle Eastern population. The mineral intake was estimated from the baseline food frequency questionnaire, adjusted by using the nutrient density method, and divided into quintiles. We used Cox proportional hazards models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the mortality. We analyzed 41,863 subjects with a mean age of 51.46 ± 8.73 years at the baseline. During 578,694 person-years of follow-up (median: 14.1 Years), 7217 deaths were recorded. Dietary calcium intake was inversely associated with the all-cause mortality (HRQ5 vs. Q1 = 0.91, 95%CI = 0.85-0.99). We observed significant associations between calcium (HRQ5 vs. Q1 = 0.82, 95% CI = 0.73-0.93), copper (HRQ5 vs. Q1 = 1.11, 95% CI = 0.99-1.26), and selenium intake (HRQ5 vs. Q1 = 1.14, 95% CI = 1.01-1.29) and CVD mortality. Dietary phosphorus (HRQ5 vs. Q1 = 0.81, 95%CI = 0.69-0.96) and copper intake (HRQ5 vs. Q1 = 0.84, 95%CI = 0.71-0.99) were inversely associated with cancer mortality. In this study within a Middle Eastern population, a higher dietary intake of calcium exhibited an inverse association with all-cause mortality. Furthermore, nuanced associations were observed in the cause-specific mortality, suggesting potential avenues for dietary interventions and emphasizing the importance of considering dietary factors in public health strategies.

Zinc and selenium status in coronavirus disease 2019

We systematically analyzed and attempted to discuss the possibility that deficiencies of zinc or selenium were associated with the incidence and severity of COVID-19. We searched for published and unpublished articles in PubMed, Embase, Web of Science and Cochrane up to 9 February 2023. And we selected healthy individuals, mild/severe, and even deceased COVID-19 patients to analyze their serum data. Data related to 2319 patients from 20 studies were analyzed. In the mild/severe group, zinc deficiency was associated with the degree of severe disease (SMD = 0.50, 95% CI 0.32-0.68, I2 = 50.5%) and we got an Egger's test of p = 0.784; but selenium deficiency was not associated with the degree of severe disease (SMD = - 0.03, 95% CI - 0.98-0.93, I2 = 96.7%). In the surviving/death group, zinc deficiency was not associated with mortality of COVID-19 (SMD = 1.66, 95%CI - 1.42-4.47), nor was selenium (SMD = - 0.16, 95%CI - 1.33-1.01). In the risk group, zinc deficiency was positively associated with the prevalence of COVID-19 (SMD = 1.21, 95% CI 0.96-1.46, I2 = 54.3%) and selenium deficiency was also positively associated with the prevalence of it (SMD = 1.16, 95% CI 0.71-1.61, I2 = 58.3%). Currently, serum zinc and selenium deficiencies increase the incidence of COVID-19 and zinc deficiency exacerbates the disease; however, neither zinc nor selenium was associated with mortality in patients with COVID-19. Nevertheless, our conclusions may change when new clinical studies are published.

Current Status and Future Prospects for Esophageal Cancer

Esophageal cancer (EC) is the ninth most common cancer and the sixth leading cause of cancer deaths worldwide. Esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) are the two main histological subtypes with distinct epidemiological and clinical features. While the global incidence of ESCC is declining, the incidence of EAC is increasing in many countries. Decades of epidemiologic research have identified distinct environmental exposures for ESCC and EAC subtypes. Recent advances in understanding the genomic aspects of EC have advanced our understanding of EC causes and led to using specific genomic alterations in EC tumors as biomarkers for early diagnosis, treatment, and prognosis of this cancer. Nevertheless, the prognosis of EC is still poor, with a five-year survival rate of less than 20%. Currently, there are significant challenges for early detection and secondary prevention for both ESCC and EAC subtypes, but Cytosponge™ is shifting this position for EAC. Primary prevention remains the preferred strategy for reducing the global burden of EC. In this review, we will summarize recent advances, current status, and future prospects of the studies related to epidemiology, time trends, environmental risk factors, prevention, early diagnosis, and treatment for both EC subtypes.

Serum Selenium, Vitamin A, and Vitamin E Levels of Healthy Individuals in High- and Low-Risk Areas of Esophageal Cancer

Background: Esophageal cancer is one of the main causes of cancer mortality in the world. Golestan province, in the northern part of Iran, has the highest esophageal cancer rate in the world. The north and south districts of Golestan province can be classified as low and high-risk areas for esophageal cancer. One of the potential risk factors for esophageal cancer in this population is a nutrient-deficient diet. Dietary antioxidant compounds such as selenium, vitamin E, vitamin A, and β-carotene are reactive oxygen species (ROC) scavengers that play a key role in cellular responses to oxidative stress and preventing DNA damage. This study aims to compare the serum levels of selenium, vitamin E, and vitamin A in healthy individuals in high and low-risk areas of esophageal cancer. Methods: This study is a population of 242 healthy individuals. Serum selenium levels were assessed by atomic absorption spectroscopy. Vitamin E and A were assessed by reversed-phase high-performance liquid chromatography. Results: Vitamin E levels of healthy individuals in high-risk areas were significantly lower than in low-risk areas, while there was no significant difference between the selenium and vitamin A levels of healthy individuals in high-risk areas and low-risk areas. Also, there was no significant difference between selenium, vitamin E, and vitamin A levels in urban and rural areas and men and women in Golestan province. Conclusion: High levels of selenium with lower levels of vitamin E, along with other risk factors, may be associated with esophageal squamous cell carcinoma in high-risk areas of Golestan province.

Decreased Serum Selenium Levels of COVID-19 Patients in Comparison with Healthy Individuals

BACKGROUND

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the cause of the COVID-19 pandemic and is the cause of increased mortality, especially among elderly patients and those who have severe complications, such as chronic pulmonary obstruction, hypertension, diabetes, and cancer. Nutrition, especially micronutrients, plays an important role in reducing mortality and complications from COVID-19 because micronutrients strengthen our immune system and nutritional status is an important factor that affects the outcome of patients with COVID-19. Among micronutrients, selenium has an important effect on both intrinsic and acquired immunity. Host selenium deficiency affects the viral genome and increases the virulence of viruses. We have investigated the serum selenium levels in COVID-19 patients and healthy control individuals.

METHODS

A total of 50 patients with COVID-19 infection were included in this study. During hospitalization, 13 patients died (non-survivor group) and 37 patients recovered (survivor group). We assessed the serum selenium levels in 50 COVID-19 patients and 50 healthy individuals by Agilent SpectrAA-240 Z atomic absorption spectrometer.

RESULTS

The serum selenium level was significantly lower in COVID-19 patients (77. 8 ± 13.9 μg/L) as compared to healthy control individuals (91.7 ± 16.7 μg/L), but there was no significant difference between the survivor and non-survivor groups. Also, there was no significant relationship between serum selenium levels and laboratory findings of COVID-19 patients.

CONCLUSIONS

These results suggest that decreased serum selenium levels may be a risk factor for the COVID-19 infection, but there was no significant relationship between selenium and severity and mortality of COVID-19 disease.

Five Serum Trace Elements Associated with Risk of Cardia and Noncardia Gastric Cancer in a Matched Case-Control Study

Background

Serum trace elements have for some time been suggested to influence the development of gastric cancer, but evidence is still lacking.

Methods

All newly diagnosed patients with gastric cancer were compared with healthy controls 1:1 matched by sex, age (±3 years), and place of residence during 2013-2015. The serum concentration of all trace elements was analyzed using inductively coupled plasma mass spectrometry. Heliobacter pylori infections in cases were diagnosed using the rapid urease test, while in controls were detected using the colloidal gold method.

Results

A total of 122 cases of gastric cardia cancer (GCC) and 177 gastric noncardia cancer (NCGC), and 299 matched healthy controls were included. Positive associations were found between serum copper and copper/zinc ratio and risk of overall gastric cancer (OR_{4th vs 1st quartile}: 2.42, 95% CI: 1.10-5.32 for copper; OR_{4th vs 1st quartile}: 11.7, 95% CI: 3.83-35.6 for copper/zinc ratio), and for both GCC and NCGC subtypes. Serum selenium was inversely associated with the risk of NCGC (OR_{4th vs 1st quartile}: 0.18, 95% CI: 0.07-0.51), while molybdenum seems to reduce the risk of GCC (OR_{4th vs 1st quartile}: 0.12, 95% CI: 0.03-0.47). Strong inverse associations were also detected between serum calcium and risk of all groups of gastric cancer (all p for trend<0.05).

Conclusion

The current study indicated statistically significant positive associations between serum copper, copper/zinc ratio, and gastric cancer, as well as inverse associations among selenium, molybdenum, and calcium. The results shall be carefully interpreted before further in vivo animal studies show definitive evidence.

Effects of High-Dose Selenium Supplementation on Oxidative Stress and Inflammatory Markers in Critically Ill Children After Gastrointestinal Surgery: A Randomized Clinical Trial

Background: Pediatric observational studies have indicated that most critically ill children have low serum selenium level, which is associated with the increased incidence of multiple organ failure and deteriorated clinical outcomes. Selenium plays a key role in the endogenous antioxidant defense mechanism and inflammatory pathways. Objectives: The present study aimed to assess the effects of high-dose selenium supplementation on the improvement of inflammatory and oxidative stress indices, as well as clinical outcomes, in pediatric patients with severe oxidative stress and inflammation following major gastrointestinal surgeries. Methods: This prospective, single-blind, randomized, parallel group superiority trial was conducted at the pediatric intensive care unit (PICU) of Akbar Pediatric Hospital in Mashhad, Iran in 2019. Patients were assigned to the supplementation (high-dose selenium: 20 µg/kg/d) and control groups (placebo with the recommended dietary allowance doses of selenium) using stratified blocks. Among 72 eligible critically ill children after gastrointestinal surgery, 66 patients completed the study. Inflammatory markers were measured and compared between the groups, including high-sensitivity C-reactive protein (hsCRP), interleukin 1 beta (IL-1β), prooxidant-antioxidant balance (PAB) assay, and clinical outcomes. Data analysis was performed in SPSS version 20 using the intention-to-treat approach. Results: Only 14 patients had optimal serum selenium concentrations before the surgery and PICU admission. At the end of the study, 90.6% of the patients (n = 29) in the intervention group and 100% (n = 34) of those in the placebo group had suboptimal serum selenium levels (< 50 ng/mL). Although supplementation with high-dose selenium decreased the inflammatory markers in the post-surgical critically ill children (-18 mg/mL and -37.5 pg/mL for hsCRP and IL-1β, respectively), the administered dose could not improve the serum glutathione peroxidase (GPx) concentrations as the selenium functional marker, as well as the PAB assay as the single test to assess the balance/imbalance of the oxidants and antioxidants simultaneously. Additionally, clinical outcomes such as infections, length of ICU stay, and 28-day mortality did not improve after the intervention. Conclusions: According to the results, high-dose selenium supplementation (20 µg/kg/d) in the post-surgical critically ill children could improve the serum inflammatory markers. However, the changes were suboptimal with no significant effects of the serum GPx concentrations, antioxidant defense system, and clinical outcomes.

Nutritional Factors Involved in the Etiology of Gastric Cancer: A Systematic Review

CONTEXT

Since treatment options for GC are limited, the best and most effective way is to try to reduce the incidences and understanding prevention strategies.

OBJECTIVE

The success in prevention strategies depends on understanding etiologic mechanisms. Our goal is to identify the major nutritional risk factors for GC, and we will examine the controversial evidence.

DATA SOURCES

We used Pub Med, Google Scholar, Scopus, Science Direct, Elsevier, Springer, and MEDLINE databases for extracting articles.

DATA EXTRACTION

Human studies published in English from 1997to2018 were included. Two reviewers other than authors initially assessed abstract of 742 papers and 248papers were selected for future assessments. After full review and consideration of the inclusion and exclusion criteria, we used 85 articles.

RESULTS

Dietary salt is a strong independent risk for GC whereas alcohol is most likely a risk only in the presence of heavy alcohol consumption. Red meat and high-fat diet increase the risk of developing GC but fresh fruits, vegetables and certain micronutrients like selenium and vitamin C are protective.

CONCLUSION

Some nutrients such as selenium, vitamin C, folate, iron, and zinc are involved in the etiology of GC. On the other hand; salt, fats, alcohol, red meat, and pepper were reported to be risk factors for GC. Since the GC is a heterogeneous malignancy and multiple factors are involved in its genesis.

Association between selenium, cadmium, and arsenic levels and genetic polymorphisms in DNA repair genes (XRCC5, XRCC6) in gastric cancerous and non-cancerous tissue

Gastric cancer is one of the most prevalent cancers in northern Iran. The DNA repair genes X-ray repair cross-complementing (XRCC) group 5, XRCC6, which are important members of non-homologous end-joining repair system, play an important role in repairing the DNA double-strand breaks. Chronic exposure to heavy metals has long been recognized as being capable of augmenting gastric cancer incidence among exposed human populations. Since trace elements could directly or indirectly damage DNA, and polymorphism in DNA DSBs-repair genes can alter the capacity of system repair, we assumed that XRCC5 VNTR and XRCC6-61C >G polymorphism also impress the DSBs-repair system ability and contribute to gastric cancer. Therefore, the objective of this research was to evaluate the tissue accumulation of Selenium (Se), Cadmium (Cd) and Arsenic (As), and XRCC5 VNTR, XRCC6-61C >G polymorphisms in cancerous and non-cancerous tissues in Golestan province. The study population included 46 gastric cancer patients and 43 cancer-free controls. Two polymorphisms of XRCC5, XRCC6 were genotyped using polymerase chain reaction (PCR) or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Further employed was atomic absorption spectroscopy so as to determine the levels of Se, Cd and As. Finally, the data were analyzed by SPSS (version 16) statistical software. The Se level was significantly higher in tumors as compared to non-tumor tissues, but there was no significant correlation between As and Cd in cancerous and noncancerous tissues. Allele frequencies of the selected genes were not statistically different between groups regarding XRCC6 (-61C>G). XRCC5 0R/0R, 0R/1R, 1R/1R, and 0R/2R genotypes were more common in cancerous group. High levels of Se in cancerous tissues vs. non-cancerous tissues may be one of the carcinogenic factors; in Golestan province, unlike other regions of Iran and the world, the level of Se is high, hence the higher risks of gastric cancer.

Toenail mineral concentration and risk of esophageal squamous cell carcinoma, results from the Golestan Cohort Study

Studies conducted in China linked selenium deficiency to higher risk of esophageal squamous cell carcinoma (ESCC), but this has not been widely tested outside that selenium-deficient region. The aim of this study was to investigate the association between selenium and other mineral concentrations in toenails and risk of ESCC in a region with high incidence rates. In this nested case-control study, we identified 222 cases of ESCC from the Golestan Cohort Study, Iran, which has followed up 50,045 participants since enrollment (2004-2008). We randomly selected one control for each case matched by age and sex, using incidence density sampling. We used toenail samples collected at baseline to measure the concentration of selenium, zinc, chromium, mercury, and scandium using instrumental neutron activation analysis. Multivariate adjusted logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals. Median nail selenium, zinc, chromium, and mercury levels were 1.01, 74.59, 0.77, and 0.018 μg/g in cases and 1.02, 75.71, 0.71, and 0.023 μg/g in controls, respectively. The adjusted odds ratios comparing each fourth quartile of mineral status versus the first quartile were as follows: selenium = 0.78 (95% CI, 0.41-1.49); zinc=0.80 (95% CI, 0.42-1.53); chromium = 0.91 (95% CI, 0.46-1.80); and mercury=0.61 (95% CI, 0.27-1.38), and all trend tests were non-significant. The nail selenium concentration in our controls reflects relatively high selenium status. No evidence of association between selenium or chromium concentrations in toenails and the risk of ESCC was detected in this population.

Decreased Expression of Selenoproteins as a Poor Prognosticator of Gastric Cancer in Humans

The aim of the present study was to analyze the selenoprotein expression levels in gastric cancer patients. We enrolled 40 patients (29 males, 11 females) who were recently diagnosed with gastric cancer and 50 healthy people (30 males, 20 females) as controls. The expression of 25 selenoprotein genes (Dio1, Dio2, Dio3, Gpx1, Gpx2, Gpx3, Gpx4, Gpx6, SelH, SelI, SelK, SelM, SelN, SelO, SelP, SelS, SelT, SelV, SelW, SelX, Sel15, Sps2, TR1, TR2, and TR3) in human gastric cancer tissues, para-carcinoma tissues, adjacent normal gastric tissues, erythrocytes, and lymphocytes in the gastric cancer group and healthy control group was analyzed by qRT-PCR. Here, we showed that among the 25 selenoproteins, 13 selenoproteins in erythrocytes (Gpx1, Gpx4, Sel15, TR1, TR2, SelH, SelK, SelM, SelO, SelS, SelV, SelW, and Sps2), 15 selenoproteins in lymphocytes (Gpx1, Gpx4, Sel15, TR1, TR2, SelH, SelK, SelN, SelO, SelS, SelT, SelV, SelX, SelW, and Sps2) and 13 selenoproteins in gastric cancer and para-carcinoma tissues (Dio1, Dio2, Dio3, Gpx1, Gpx4, Sel15, SelH, SelK, SelM, SelS, SelT, SelW, and Sps2) were significantly decreased (P < 0.05) in the gastric cancer group compared to the control group. In summary, the decreasing expression of selenoprotein genes in gastric cancer patients play an important role in the gastric cancer, although further studies are needed to better understand our findings.

The Relationship between Serum Selenium and Zinc with Gastroesophageal Cancers in the Southeast of Iran

BACKGROUND

Selenium (Se) and zinc (Zn) have antioxidant and anticancer properties.

OBJECTIVE

The aim of this study was to evaluate the serum levels of Se and Zn and the correlation between the levels of these two elements with risk of incidence of esophageal cancer (EC) and gastric cancer (GC).

MATERIALS AND METHODS

In a case-control study, we selected sixty patients with GC or EC as the intervention group and 120 age-matched individuals as the control group. Exclusion criteria were the individuals with kidney and liver failure and the consumer of dietary supplements such as Se and Zn. Measurement of serum Se was done in a graphite furnace system and atomic absorption device of Varian and of serum Zn was done by a flame photometer system (flame) and atomic absorption device of Varian.

RESULTS

In thirty patients of ECs, 90% were squamous cell carcinoma and 10% adenocarcinoma, and out of thirty patients of GCs, 90% were intestinal type and 10% diffuse type. The level of two elements in cancer patients was lower than the control group (P < 0.05). There was no significant different between two cancer groups for level of Se and Zn, but there was a significant difference between the control group with two other groups.

CONCLUSION

Our study confirmed the findings from previous prospective studies and randomized trials that reducing of lower levels of Se and Zn can effect on incidence of cancer.

The Content of Plasma Selenium in Early Admitted Septic Patients

OBJECTIVE

Selenium depletion has been reported in critical illness correlates with an increase in mortality and morbidity. In this study, we aimed to access the selenium plasma levels of septic patients early at the Intensive Care Unit (ICU) admission in order to compare with reference range.

METHODS

We conducted a cross-sectional study in a university affiliated hospital aiming to assess the early plasma level of selenium in ICU admitted patients. eighty patients diagnoses with sepsis were included and considered for characteristic evaluation, monitoring criteria assessment and also blood sampling. All blood sampling was performed during 48 hours of the ICU admission in order to determined the plasma Selenium level by atomic absorption method.

FINDINGS

The mean plasma levels of selenium in male and female was 98.14 ± 23.52 and 78.1 ± 24.46 μ/L, respectively. Although selenium plasma levels was higher in the ICU male patients significantly, both had near normal range (80 μ/L).

CONCLUSION

In this study we found that in early admitted Iranian ICU patients in Tehran, selenium deficiency has not routinely seen but probably will happen during ICU hospitalization.

The Nail as a Biomonitor of Trace Element Status in Golestan Cohort Study

BACKGROUND

In the Golestan Cohort Study that was launched to investigate the causes of esophageal cancer, a complete biospecimen bank was established for storage of collected blood, urine, hair, and nail samples. The objective of this study was to evaluate the feasibility of nail samples as a biomarker of selected trace elements status.

METHODS

Thirty toenail samples were selected randomly from the participants of Golestan Cohort Study (GCS). The samples were cleaned and analyzed for selenium, mercury, chromium, iron, zinc, and scandium by instrumental neutron activation analysis at the University of Missouri Research Reactor Center. Pearson correlation coefficients were computed for selected trace elements concentration versus scandium concentration to assess terrestrial contamination.

RESULTS

The selenium, zinc, and mercury were not correlated with scandium, suggesting they were free from substantial contamination. The high correlations of scandium with iron and chromium suggest that the iron and chromium levels may be compromised by terrestrial contamination. The coefficients of variation for duplicate samples for selenium and zinc were 2.6% and 7.2%, respectively.

CONCLUSION

The nail samples from Golestan Cohort Study appears to be useable as a biomarker of selenium, zinc, and mercury and could be considered for use in future studies.

Effects of selenium supplementation on glucose homeostasis and free androgen index in women with polycystic ovary syndrome: A randomized, double blinded, placebo controlled clinical trial

BACKGROUND/OBJECTIVES

Insulin resistance (IR) is a main pathophysiologic feature in polycystic ovary syndrome (PCOS) patients which is triggered by elevated oxidative stress in these patients. Selenium, an essential micronutrient, is a major constituent of antioxidant enzymes such as glutathione peroxidase. Recently, decreased plasma selenium concentrations were reported in PCOS patients. So, the present study was carried out in order to assess whether selenium consumption can improve the metabolic response to insulin and reduce the insulin resistance in these women.

SUBJECTS/METHODS

A total of 53 PCOS patients (diagnosed by Rotterdam criteria), 18-42 years old, participated in this randomized, double-blind and placebo controlled trial for 12 weeks (selenium, n=26; placebo, n=27). The effects of daily administration of 200 μg selenium or placebo on serum glucose, total testosterone (tT), sex hormone binding globulin (SHBG) and free androgen index (FAI) in fasting state were evaluated.

RESULTS

At the end of the study, insulin resistance was significantly increased in selenium recipients when compared with the placebo group (2.05 ± 0.39 when compared with 1.81 ± 0.25, p=0.017). Also, selenium supplementation resulted in marginally significant increase (p=0.056) in insulin level when compared with the placebo group. There were no statistically significant changes in other study endpoints, when comparing the two groups.

CONCLUSION

This study showed that selenium supplementation in PCOS patients may worsen insulin resistance in them. Until the results of larger studies become available, indiscriminate consumption of selenium supplements in PCOS patients will warrant caution.

Dietary intake of minerals and risk of esophageal squamous cell carcinoma: results from the Golestan Cohort Study

BACKGROUND

Dietary factors have been hypothesized to affect the risk of esophageal cancer via different mechanisms, but the intake of minerals is understudied and the evidence is conflicting.

OBJECTIVE

The objective was to evaluate the associations of dietary intake of minerals with risk of esophageal squamous cell carcinoma (ESCC).

DESIGN

We used data from the Golestan Cohort Study, which was launched in a high-risk region for esophageal cancer in Iran. Participants were enrolled in 2004-2008 and were followed to 2014. Intakes of minerals were assessed with a validated food-frequency questionnaire. A Cox proportional hazards model was used to estimate HRs and 95% CIs of ESCC for dietary intakes of selected minerals.

RESULTS

We identified 201 ESCC cases among 47,405 subjects. Calcium intake was significantly inversely associated with the risk of ESCC (HR per 100-mg/d increase: 0.88; 95% CI: 0.81, 0.96; P = 0.005; quartile 4 vs. quartile 1 HR: 0.49; 95% CI: 0.29, 0.82; P-trend = 0.013). Zinc intake was also inversely associated with ESCC, but the quartile association did not reach significance (HR per 1-mg/d increase: 0.87; 95% CI: 0.77, 0.98; P = 0.027; quartile 4 vs. quartile 1 HR: 0.56; 95% CI: 0.28, 1.12; P-trend = 0.097). The relations between dietary intakes of selenium, magnesium, and copper and risk of ESCC were nonlinear (P-nonlinear trend = 0.001, 0.016, and 0.029, respectively). There was no relation between dietary intake of manganese and the risk of ESCC.

CONCLUSION

The results suggest that higher intakes of calcium and zinc are associated with a lower risk of ESCC in a high-risk region of Iran.

Serum selenium level in patients with gastric non-cardia cancer and functional dyspepsia

BACKGROUND

Gastric cancer (GC) is the most common gastrointestinal cancer in Iran. Helicobacter pylori (H. pylori) accounts as one of the main risk factors for gastric non-cardia cancer (GNCC). It is suggested that high serum selenium level may have a protective role in GNCC. In this cross-sectional study, we determined the serum Se level and the status of H. pylori infection in two populations with GC and functional dyspepsia (FD).

METHODS

The enrolled patients were 85 (27 women, 58 men) with recent pathologically proven GNCC (adenocarcinoma) and 85 (34 women, 51 men) FD patients. Serum Se was measured by atomic absorption spectrophotometry. H. pylori IgG antibody was detected by quantitative enzyme immunoassay.

RESULTS

The mean age in the GNCC and FD patients were 62.85±14.6 and 58.9±14.7 years, respectively (P=0.08). The serum selenium levels were 111.6±27.7 and 129.9±32.1 μg/L (mean±SD) in GNCC and FD patients, respectively (P<0.001). The frequency of H. pylori infection was 49.4% (n=42) and 68.2% (n=58) in GNCC and FD patients (P=0.013). The crude and adjusted odds ratio (OR) between GNCC and the linear effect of serum selenium level were 0.98 and 0.982, respectively (P=0.002). This means that each unit increase in serum selenium level decreases the odds of cancer by 2%.

CONCLUSION

Serum selenium level was significantly lower in GNCC cases. It suggests that lower serum selenium might have some association with the risk of GNCC. H. pylori infection does not play a significant impact on this association.

Dietary habits and esophageal cancer

Cancer of the esophagus is an underestimated, poorly understood, and changing disease. Its overall 5-year survival is less than 20%, even in the United States, which is largely a function of a delay in diagnosis until its more advanced stages. Additionally, the epidemiologic complexities of esophageal cancer are vast, rendering screening and prevention limited at best. First, the prevalence of esophageal cancer is unevenly distributed throughout the world. Second, the two histological forms (squamous cell and adenocarcinoma) vary in terms of their geographic prevalence and associated risk factors. Third, some populations appear at particular risk for esophageal cancer. And fourth, the incidence of esophageal cancer is in continuous flux among groups. Despite the varied prevalence and risks among populations, some factors have emerged as consistent associations while others are only now becoming more fully recognized. The most prominent, scientifically supported, and long-regarded risk factors for esophageal cancer are tobacco, alcohol, and reflux esophagitis. Inasmuch as the above are regarded as important risk factors for esophageal cancer, they are not the sole contributors. Dietary habits, nutrition, local customs, and the environment may be contributory. Along these lines, vitamins, minerals, fruits, vegetables, meats, fats, salted foods, nitrogen compounds, carcinogens, mycotoxins, and even the temperature of what we consume are increasingly regarded as potential etiologies for this deadly although potentially preventable disease. The goal of this review is to shed light on the less known role of nutrition and dietary habits in esophageal cancer.

Adherence to Mediterranean-style dietary pattern and risk of esophageal squamous cell carcinoma: a case-control study in Iran

OBJECTIVE

The benefit of adherence to a Mediterranean-style dietary pattern in relation to the risk of esophageal squamous cell carcinoma (ESCC) has not been investigated among non-Mediterranean high-risk populations. The objective of the present study was to examine the association of compliance with the Mediterranean dietary pattern as measured by Mediterranean-Style Dietary Pattern Score (MSDPS) and the risk of ESCC in Iranian population.

METHODS

This case-control study was conducted on 47 ESCC cases and 96 hospital controls aged 40-75 years. Participants were interviewed using validated questionnaires, and dietary patterns were characterized using the MSDPS.

RESULTS

Generally, the mean MSDPS in this population was low (30.84 ± 8.58). MSDPS showed content validity through having expected positive associations with several lifestyle characteristics and dietary intakes. Being in the highest quartile category of MSDPS, compared to the lowest, was independently associated with 37% reduction in risk of ESCC. Two-unit and 3-unit increases in the MSDPS resulted in 41% and 47% reduction in risk of ESCC, respectively. Higher intakes of olive oil (odds ratio [OR] = 0.15, 95% CI: 0.01-0.49), fish and other seafood (OR = 0.48, 95% CI: 0.23-0.98), whole grain (OR = 0.57, 95% CI: 0.28-0.76), and fruits (OR = 0.77, 95% CI: 0.38-0.86) were significantly associated with reduced ESCC risk. In contrast, higher sweet (OR = 1.86, 95% CI: 1.04-2.12) and meat intakes (OR = 1.61, 95% CI: 1.25-2.49) were associated with higher ESCC risk.

CONCLUSION

Consuming a diet in concordance with the principles of the Mediterranean dietary pattern may protect against ESCC. Preventive strategies to reduce ESCC risk in high-risk countries should focus on overall dietary pattern and dietary habits to be effective.

The gastro-esophageal malignancies in Northern Iran research project: impact on the health research and health care systems in Iran

BACKGROUND

The Gastro-Esophageal Malignancies in Northern Iran (GEMINI) research project is an example of recent progress in health research in Iran. The original aim of this project was to identify etiologic factors and prevention measures for upper gastrointestinal cancers in Northern provinces of Iran, but its achievements have gone much beyond this initial goal.

METHODS

GEMINI consists of several projects including cancer registries, pilot studies, case-control studies, and the Golestan Cohort Study. GEMINI has been conducted through extensive collaborations between the Digestive Disease Research Center of Tehran University of Medical Sciences with other domestic and international health organizations. The achievements of GEMINI include producing new knowledge, introducing new research methods, developing and expanding health research and health care infrastructures, investing in human resources, and increasing the awareness and knowledge of policy makers and officials at all levels about the importance of chronic diseases in Iran's health priorities.

CONCLUSION

The success of GEMINI reveals the feasibility of large-scale health research studies in developing countries and serves as a successful model not only for health research in Iran, but also for similar research studies in other developing nations.

Effect of selenium on immune response against hepatitis B vaccine with accelerated method in insulin-dependent diabetes mellitus patients

BACKGROUND

Poor response to various vaccines especially hepatitis B is common. The purpose of this study was to evaluate the effect of selenium on immune response against hepatitis B vaccine with accelerated method in insulin-dependent diabetes mellitus patients.

METHODS

In this randomized clinical trial study, 62 insulin dependent diabetic patients were divided into case and control groups (each of 31 cases). In the control group, hepatitis B vaccine 20 µg was done by intra-deltoid injection on a 0, 10, 21 day schedule with placebo, and in case group, 200 µg of selenium as a supplement was added once daily to same vaccine schedule from the first day to the 30(th) day of the month. After one month, serum sample was obtained and evaluated for anti-HBs using ELISA method. Data were collected and analyzed.

RESULTS

In the case group, 23 cases (74.2%) and in control group, 15 cases (48.4%) achieved protective level of anti-HBs irrespective to sex and age (p=0.037). The mean antibody levels were 233.75±163.45U/L and 144±69.29U/L in selenium and control groups, respectively.

CONCLUSION

Our study showed that selenium could help to increase protective rate and level of anti-HBs by accelerated vaccination method. Adding selenium by routine HBV vaccination in diabetic patients is recommended for increasing the rate and level of anti-HBs in such group.

The role of selenium and selected trace elements in the etiology of esophageal cancer in high risk Golestan province of Iran

Selenium (Se) deficiency is reported by some authors to be an important factor in the etiology of esophageal cancer (EC) in the Golestan province of Iran. In order to further investigate the role of Se and selected trace elements in the occurrence of EC disease, 663 samples including 206 cultivated soils, 247 sediments, 45 loess deposits and 165 grain samples from 45 villages in the Golestan province of Iran were collected and analyzed. Villages in the study area were classified into 2 groups according to the EC incidence in the local population. The results of this study demonstrate that, contrary to the expected trend, total Se concentrations in soil, grain, sediment, and loess samples increase from the low to the high EC areas suggesting that Se deficiency does not play a major role in the etiology of EC. On the other hand, antimony (Sb), and strontium (Sr) content in soil, grain, loess, and sediment samples is much higher in the high esophageal cancer area, which may be a significant factor. Total zinc (Zn) concentrations in soil, grain, loess, and sediment samples decrease from the low to the high cancer areas. Therefore, Zn deficiency may be a significant factor in EC incidence rate in the Golestan province.

None-endoscopic Screening for Esophageal Squamous Cell Carcinoma- A Review

Esophageal cancer (EC) is the eighth most common cancer and sixth most frequent cause of cancer mortality worldwide. Esophageal squamous cell carcinoma (ESCC) is the most common type of EC. ESCC develops by progression from premalignant lesions, which are called esophageal squamous dysplasia (ESD). Prevention is the most effective strategy for controlling this disease. Generally, two methods may be defined for ESCC prevention. The aim of the first preventive method is to prevent the initiation of ESD by avoiding the known risk factors, or primary prevention. Secondary prevention focuses on detection of the disease in its early curable stage, thus preventing its progression into advanced stages. Endoscopy with iodine staining and biopsy is the diagnostic choice for ESD. However it is invasive and expensive, and not accepted by asymptomatic ESD cases. Therefore, it is necessary to find a non-endoscopic screening method. Despite the large number of studies conducted worldwide, no approved method has been developed for ESCC screening. Regarding the multi-factorial nature of ESCC, it is proposed that the use of a combination of various criteria, such as cytological examination, risk factors, genetic alteration, and molecular markers may result in the development of a comprehensive and effective ESCC screening program.

Quality of drinking water and high incidence rate of esophageal cancer in Golestan province of Iran: a probable link

Golestan province in north Iran is known to be a high-risk area for esophageal cancer (EC). Of a long list of multiple risk factors, this study focuses on a possible link between the epidemiologic patterns of EC and the anomalous concentration of some ions and elements in the drinking water sources. A total of 183 samples from 45 villages covering a wide range of EC mortality rates are collected and analyzed. The results demonstrate that NO(3)(-), SO(4)(2-), Sb, and Sr exceed the recommended maximum concentration level (MCL) in drinking water. This is more prominent in the villages with high esophageal cancer mortality rate, suggesting a possible link between EC incidence and water quality. Se concentration in drinking water increases from low to the high EC areas, a finding contrary to the expected trend. It is concluded that Se deficiency does not play a major role in the etiology of EC in the Golestan province. The statistical results obtained from Mann-Whitney and Kruskal-Wallis tests along with cluster analysis are consistent with the observed trend of EC mortality rate in Golestan province.

Macronutrients, vitamins and minerals intake and risk of esophageal squamous cell carcinoma: a case-control study in Iran

Background

Although Iran is a high-risk region for esophageal squamous cell carcinoma (ESCC), dietary factors that may contribute to this high incidence have not been thoroughly studied. The aim of this study was to evaluate the effect of macronutrients, vitamins and minerals on the risk of ESCC.

Methods

In this hospital-based case-control study, 47 cases with incident ESCC and 96 controls were interviewed and usual dietary intakes were collected using a validated food frequency questionnaire. Data were modeled through unconditional multiple logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), controlling for age, sex, gastrointestinal reflux, body mass index, smoking history (status, intensity and duration), physical activity, and education.

Results

ESCC cases consumed significantly more hot foods and beverages and fried and barbecued meals, compared to the controls (p < 0.05). After adjusting for potential confounders, the risk of ESCC increased significantly in the highest tertiles of saturated fat [OR:2.88,95%CI:1.15-3.08], cholesterol [OR:1.53, 95%CI: 1.41-4.13], discretionary calorie [OR:1.51, 95%CI: 1.06-3.84], sodium [OR:1.49,95%CI:1.12-2.89] and total fat intakes [OR:1.48, 95%CI:1.09-3.04]. In contrast, being in the highest tertile of carbohydrate, dietary fiber and (n-3) fatty acid intake reduced the ESCC risk by 78%, 71% and 68%, respectively. The most cancer-protective effect was observed for the combination of high folate and vitamin E intakes (OR: 0.02, 95%CI: 0.00-0.87; p < 0.001). Controls consumed 623.5 times higher selenium, 5.48 times as much β-carotene and 1.98 times as much α-tocopherol as the amount ESCC cases consumed.

Conclusion

This study suggests that high intake of nutrients primarily found in plant-based foods is associated with a reduced esophageal cancer risk. Some nutrients such as folate, vitamin E and selenium might play major roles in the etiology of ESCC and their status may eventually be used as an epidemiological marker for esophageal cancer in Iran, and perhaps other high-risk regions.

Dietary habits and gastric cancer risk in north-west Iran

OBJECTIVES

North-west Iran is a high-risk area for gastric cancer (GC). Dietary practices may increase risk of GC. For the first time, the diet-GC association in this area was assessed using a validated food frequency questionnaire.

METHODS

Cases and controls were recruited in a population-based study. In addition to collecting dietary data using a food frequency questionnaire, Helicobacter pylori antibody level was measured. Multiple logistic regression models were used to estimate odds ratios for associations between dietary factors and GC among 286 cases and 304 controls.

RESULTS

A positive association was estimated for total fat intake (OR = 1.33/20 g, 95% CI: 1.12-1.57) and risk of GC. Inverse associations were observed for vitamin C, iron, and zinc intake and risk of GC and its subgroups (cardia, non-cardia). Fruits and vegetables consumption and refrigerator use showed inverse associations (OR = 0.72/100 g, 95% CI: 0.65-0.80 and OR = 0.75/10 years, 95% CI: 0.60-0.95, respectively). Positive association was observed among those who preferred fried food (OR = 2.21, 95% CI: 1.45-3.37) or consumed highly salted/roasted seeds (OR = 1.97, 95% CI: 1.13-3.43).

CONCLUSION

GC in north-west Iran is associated with dietary practices: foods, nutrients and food preparation habits.

Comparative study of levamisole-selenium supplementation effect on CD4 increase in HlV / AIDS patients

BACKGROUND

Given to the abundant incidence of malnutrition in HIV(+) patients and its effect on progress of AIDS disease, several studies have recommended supplementation therapy (such as Selenium, Levamisole, Zinc).

METHODS

This clinical trial was prefunded on patient's with HIV + in Behavior Diseases Consulting Center, Kermanshah, Iran 2006-2007. One hundred-seventy eight out of all patients with CD4 1ess than 350 cell/mm(3) who did not receive antiretroviral drugs were in this study. They were divided into four groups: the first group received 200 micg selenium per day, the second group received levamisole 50 mg every other day, and third group received both two drugs. The fourth group was the control group. All four groups were studied for six months. Patients' baseline CD4 and other data were recorded in a form. CD4 was rechecked after six months and collected values were compared with basic values. CD4 changes were compared among all groups, either.

RESULTS

One hundred-seventy eight patients initiated treatment and 108 cooperated in the 6-month follow up assessment. Niuety-two (85%) were males and 15% were female. CD4 decreased in control group and Levamisole group during the study which was significant, but 13 units increase was seen in Selenium-Levamisole group. CD4 count decreased 36 units in Selenium group. Comparing CD4 count change among 4 study groups showed that only CD4 change between Selenium-Levamisole group and control group was significant.

CONCLUSION

Regarding to collected results, Selenium-Levamisole supplementation can be used as a supplementation therapy besides antiretroviral therapies.

Helicobacter pylori and gastric cancer in the Middle East: A new enigma?

The Middle East is the home of ethnic groups from three main backgrounds: Semitic (Arabs and Jews), Indo-European (Persians and Kurdish) and Turkic (Turkish and Turkmens). Its geographic location, which has been under continuous influences from Asia, Europe and Africa, has made it an ideal site for epidemiological studies on Helicobacter pylori (H. pylori) infection and genotyping. The gastric cancer rate differs in this region from very high in Iran (26.1/10⁵) to low in Israel (12.5/10⁵) and very low in Egypt (3.4/10⁵). Epidemiological studies showed that the prevalence of H. pylori is almost similar in those countries with a high level of infection in childhood. Importantly, the frequency of vacA s1 and m1 regions and cagA+ genotypes were higher in non Semitic populations who inhabit the North than Semitic populations, the inhabitants of Southern parts of the Middle East. H. pylori infection prevalence, distribution pattern of virulence factors, diet and smoking could not have explained the difference in cancer rate. This reflects the multifactorial aetiology of gastric cancer and suggests that H. pylori infection does not always directly correlate with the risk for gastrointestinal disease, such as gastric cancer. Further detailed investigations and international comparative studies of each risk factor need to be performed to investigate whether this represents a true enigma.

Soils selenium level and esophageal cancer: an ecological study in a high risk area for esophageal cancer

PROJECT

Golestan province, located in northeast of Iran, has been known as a high risk area for esophageal cancer (EC). This study was conducted to assess the relationship between soils selenium (Se) level and development of EC in this region.

PROCEDURES

In this ecological study, 135 blocks were identified in Golestan province based on geographical altitude and longitude on the map. One soil sample was collected from the center of each block. Then we investigated Se concentration in soil samples by flame atomic absorption spectrometry. Statistical analysis was performed by the Pearson correlation test and Student t-tests. P-values of less than 0.05 were considered as significant.

RESULTS

The mean+/-SD of soils Se level in Golestan province was 3.7+/-1.61 mg/kg. There was a positive correlation between soils Se level and EC rates in this area (P=0.03) (Pearson correlation coefficient=0.19). Soils Se concentration was significantly higher in high (4.13 mg/kg) than in the low (3.39 mg/kg) EC rate areas (P=0.01).

CONCLUSIONS

We found high soils Se concentration and a significant positive relationship between soils Se level and EC rate in Golestan province of Iran. So, high soils Se level may play a possible role in developing EC in this area, specifically in Turkmensahra (very high EC rates).

The changing face of esophageal cancer

The two main histological esophageal cancer types, adenocarcinoma and squamous cell carcinoma, differ in incidence, geographic distribution, ethnic pattern and etiology. This article focuses on epidemiology with particular reference to geographic and temporal variations in incidence, along with a review of the evidence supporting environmental and genetic factors involved in esophageal carcinogenesis. Squamous cell carcinoma of the esophagus remains predominantly a disease of the developing world. In contrast, esophageal adenocarcinoma is mainly a disease of western developed societies, associated with obesity and gastro-esophageal reflux disease. There has been a dramatic increase in the incidence of adenocarcinoma in developed countries in parallel with migration of both esophageal and gastric adenocarcinomas towards the gastro-esophageal junction.

Oesophageal cancer in Golestan Province, a high-incidence area in northern Iran - a review

Golestan Province, located in the south-east littoral of the Caspian Sea in northern Iran, has one of the highest rates of oesophageal cancer (OC) in the world. We review the epidemiologic studies that have investigated the epidemiologic patterns and causes of OC in this area and provide some suggestions for further studies. Oesophageal squamous cell carcinoma (OSCC) constitutes over 90% of all OC cases in Golestan. In retrospective studies, cigarettes and hookah smoking, nass use (a chewing tobacco product), opium consumption, hot tea drinking, poor oral health, low intake of fresh fruit and vegetables, and low socioeconomic status have been associated with higher risk of OSCC in Golestan. However, the association of tobacco with OSCC in this area is not as strong as that seen in Western countries. Alcohol is consumed by a very small percentage of the population and is not a risk factor for OSCC in this area. Other factors, such as polycyclic aromatic hydrocarbons, N-nitroso compounds, drinking water contaminants, infections, food contamination with mycotoxins, and genetic factors merit further investigation as risk factors for OSCC in Golestan. An ongoing cohort study in this area is an important resource for studying some of these factors and also for confirming the previously found associations.

Serum selenium levels in healthy women in Tabriz, Iran

BACKGROUND

Selenium is of fundamental importance to human health, and selenium deficiency is associated with disease conditions.

OBJECTIVE

The objective of this study was to investigate the serum level of selenium in women of childbearing age and postmenopausal women living in Tabriz, Iran.

METHODS

In this cross-sectional study, 60 healthy women of childbearing age and 60 healthy postmenopausal women were studied with the use of biochemical methods (measurement of serum selenium by graphite furnace atomic absorption spectrometry), anthropometric measurements (weight and height), and interviews.

RESULTS

The average serum selenium was 76.67 +/- 17.98 microg/L (range, 42.00 to 166.61 microg/L). This level was lower than those reported in other provinces of Iran and some other countries. Sixty-nine women (57.5%) had serum selenium concentrations under 80 microg/L. There was no significant difference in selenium level between the two groups of women. Serum selenium level did not vary with age and body mass index.

CONCLUSIONS

Some Iranian women are of borderline selenium status and as a consequence are more susceptible to selenium-deficiency diseases. There is a need for community-based programs to encourage people to increase consumption of selenium-rich sources, such as marine foods.

Geographical spread of gastrointestinal tract cancer incidence in the Caspian Sea region of Iran: spatial analysis of cancer registry data

BACKGROUND

High incidence rates of gastrointestinal tract cancers have been reported in the Caspian region of Iran. This study aimed to: 1) describe the geographical spatial patterns of gastrointestinal tract cancer incidence based on cancer registry data and, 2) determine whether geographical clusters of statistical significance exist.

METHODS

The Babol Cancer Registry, which covers the two major northern Iranian provinces of Mazandaran and Golestan (total population = 4,484,622) was used to identify new gastrointestinal tract cancer cases during 2001 to 2005. Age-specific cancer incidence rates were calculated for 7 gastrointestinal tract cancer sites in 26 wards of the Mazandaran and Golestan provinces. Spatial autocorrelation indices, hierarchical Bayesian Poisson models, and spatial scan statistics were used in measuring the geographic pattern and clusters.

RESULTS

There were non-random spatial patterns in esophageal and stomach cancers that were similar for both sexes. Clusters of high incidence were identified in esophageal, stomach, colorectal and liver cancer for both sexes, as well as a possible cluster of pancreas cancer in males.

CONCLUSION

Gastrointestinal tract cancers exhibit significant spatial clustering of risk in northern Iran. Further work is needed to relate these geographical patterns to information on potential life-style and environmental factors.

Differences in virulence markers between Helicobacter pylori strains from Iraq and those from Iran: potential importance of regional differences in H. pylori-associated disease

Helicobacter pylori causes peptic ulceration and gastric adenocarcinoma; the latter is common in Iran but not in Iraq. We hypothesized that more virulent H. pylori strains may be found in Iran than in Iraq and so compared established and newly described virulence factors in strains from these countries. We studied 59 unselected dyspeptic patients from Iran and 49 from Iraq. cagA was found in similar proportions of strains from both countries (76% in Iran versus 71% in Iraq) and was significantly associated with peptic ulcer disease in Iraq (P <or= 0.01) but not in Iran. cagA alleles encoding four or more tyrosine phosphorylation motifs were found in 12% of the Iranian strains but none of the Iraqi strains (P = 0.02). There were no significant differences in the vacA signal-, middle-, or intermediate-region types between Iranian and Iraqi strains. Among the strains from Iran, vacA genotypes showed no specific peptic ulcer associations, but among the strains from Iraq, vacA i1 strains were associated with gastric ulcer (P <or= 0.02), mimicking their previously demonstrated association with gastric cancer in Iran. dupA was found in similar proportions of Iranian and Iraqi strains (38% and 32%, respectively) and was associated with peptic ulceration in Iraqi patients (P <or= 0.01) but not Iranian patients. H. pylori strains from Iraq and Iran possess virulence factors similar to those in Western countries. The presence of cagA with more phosphorylation motifs in Iranian strains may contribute to the higher incidence of gastric cancer. However, the association between strain virulence markers and disease in Iraq but not Iran suggests that other host and environmental factors may be more important in the disease-prone Iranian population.

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Dietary Selenium Intake and Genetic Polymorphisms of the GSTP1 and p53 Genes on the Risk of Esophageal Squamous Cell Carcinoma

Few studies have assessed potential effect modifications by polymorphisms of susceptibility genes on the association between selenium intake and esophageal squamous cell carcinoma (ESCC). We studied the joint effects of dietary selenium and the GSTP1 and p53 polymorphisms on ESCC risk in a population-based case-control study with 218 ESCC cases and 415 controls in Taixing City, China. Dietary selenium intake was estimated from a food frequency questionnaire with 97 food items. GSTP1 and p53 polymorphisms were detected by RFLP-PCR assays. Logistic regression analyses were done to estimate odds ratios (OR) and 95% confidence intervals (95% CI). Reduced ESCC risk was observed among individuals in the highest quartile of dietary selenium intake (adjusted OR, 0.31; 95% CI, 0.13-0.70) with a dose-dependent gradient (P(trend) = 0.01). The p53 Pro/Pro genotype was associated with increased risk of ESCC compared with the Arg/Arg genotype (adjusted OR, 2.02; 95% CI, 1.19-3.42). When combined with selenium consumption, an obvious increased risk was observed among individuals with the p53 Pro/Pro or GSTP1 Ile/Ile genotype with adjusted ORs of 3.19 (95% CI, 1.74-5.84) and 1.90 (95% CI, 1.03-3.51), respectively. Among smokers and alcohol drinkers, elevation of ESCC risk was more prominent among p53 Pro/Pro individuals who consumed a low level of dietary selenium (adjusted OR, 3.59; 95% CI, 1.49-8.66 for smokers and 6.19; 95% CI, 1.83-20.9 for drinkers). Our study suggests that the effect of dietary selenium on the risk of ESCC may be modulated by tobacco smoking, alcohol drinking, and p53 Pro/Pro and GSTP1 Ile/Ile genotypes.

Risk factors for goiter in primary school girls in Qom city of Iran

OBJECTIVE

Goiter is endemic in Iran. The iodine deficiency disorders program was begun a few years ago in Iran, and the coverage of iodized salt is sufficient now. But, in a periodic yearly medical examination of primary school girls in Qom, the prevalence of goiter was above 30% in 2002. This survey was designed to study the risk factors of goiter in those students.

DESIGN

The study was a randomized (multistage, proportional simple random sampling) case-control study.

SUBJECTS AND INTERVENTIONS

We selected and performed thyroid examinations in 1050 girl students in primary schools in Qom city of Iran in 2002. We found 284 cases: girls in primary schools had goiter in accordance with the clinical exam of World Health Organization classification. Among students who did not present with goiter in the clinical exam, we randomly selected 288 students as the control group. We used a questionnaire to evaluate them for the risk factors of goiter.

RESULTS

The mean+/-s.d. ages of cases and controls were 8.7+/-1.3 and 8.9+/-1.3 years, respectively. There is no significant difference between the two groups regarding history of soya, kale, turnip, fish, daily iodized salt usage, education and job of mothers, monthly family income, nationality, immigration and residential situation. By using multinomial logistic regression, we found that storage of iodized salt in open containers, odds ratio (OR): 2.201 (1.412-3.428); P-value <0.0001, medium socioeconomic situation (SES) of family, OR: 2.099 (1.029-4.282), P-value=0.041, district 2 of Qom city, OR: 2.880 (1.376-6.027), P-value=0.005, and district 3 of Qom city, OR: 2.051(1.032-4.078), P-value=0.041, were the major risk factors for goiter in this population.

CONCLUSIONS

In this study, the main risk factors for goiter were storage of iodized salt in open containers, medium SES and also living in specific districts of Qom city. As the coverage of iodinized salt is over 95% in Iran, we advise the education of the family about storage of iodized salt in closed containers. We also recommend the study of the other risk factors of goiter in the different geographical areas of Iran, because of differences in the SES and nutritional habits.

SPONSORSHIP

This study was supported by issuing permission letters for our activities: (not funding support) Qom Health Network and Medical Services, Qom Medical University, Qom Primary School Education Office, Fathemieh Medical University.