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1.  Reproductive factors and risk of esophageal squamous cell carcinoma in northern Iran- A case-control study in a high risk area and literature review 
Background
Several epidemiologic studies have suggested an inverse association between female reproductive factors and risk of esophageal squamous cell carcinoma (ESCC), but the evidence is not conclusive. We investigated the association of the number of pregnancies, live-births, and miscarriages/stillbirths in women and the association of the number of children in both sexes with ESCC risk in Golestan Province, a high-risk area in Iran.
Methods
Data from 297 histopathologically confirmed ESCC cases (149 women) and 568 controls (290 women) individually matched to cases for age, sex, and neighborhood of residence were included in this analysis. Conditional logistic regression was used to calculate odds ratios (ORs) and corresponding 95% confidence intervals (CIs).
Results
The average numbers of live-births and miscarriages/stillbirths among controls were 8.2 and 0.8, respectively. Women with 6 or more live-births were at approximately one-third the risk of ESCC as those with 0–3 live-births; the OR (95% CI) for having 6–7 live-births was 0.33 (0.12–0.92). In contrast, the number of miscarriages/stillbirths was associated with an increase in ESCC risk. The OR (95% CI) for ≥ 3 versus no miscarriages/stillbirths was 4.43 (2.11–9.33). The number of children in women was suggestive an inverse association with ESCC, but this association was not statistically significant; in men, no association was seen.
Conclusion
The findings of this study support a protective influence of female hormonal factors on ESCC risk. However, further epidemiological and mechanistic studies are needed to prove a protective association.
doi:10.1097/CEJ.0b013e32835c7f87
PMCID: PMC3731403  PMID: 23238586
case-control study; esophageal cancer; miscarriage; parity; reproductive; squamous cell carcinoma
2.  Opium; an emerging risk factor for gastric adenocarcinoma 
Opium use has been associated with higher risk of cancers of the esophagus, bladder, larynx, and lung; however, no previous study has examined its association with gastric cancer. There is also little information on the associations between hookah (water pipe) smoking or the chewing of tobacco products and the risk of gastric cancer. In a case-control study in Golestan Province of Iran, we enrolled 309 cases of gastric adenocarcinoma (118 noncardia, 161 cardia, and 30 mixed-location adenocarcinomas) and 613 matched controls. Detailed information on long-term use of opium, tobacco products, and other covariates were collected using structured and validated lifestyle and food frequency questionnaires. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were obtained using conditional logistic regression models. Opium use was associated with an increased risk of gastric adenocarcinoma, with an adjusted OR (95% CI) of 3.1 (1.9 – 5.1), and this increased risk was apparent for both anatomic subsites (cardia and noncardia). There was a dose-response effect, and individuals with the highest cumulative opium use had the strongest association (OR: 4.5; 95%CI: 2.3-8.5). We did not find a statistically significant association between the use of any of the tobacco products and risk of gastric adenocarcinoma, overall or by anatomic subsite. We showed, for the first time, an association between opium use and gastric adenocarcinoma. Given that opium use is a traditional practice in many parts of the world, these results are of public health significance.
doi:10.1002/ijc.28018
PMCID: PMC3644384  PMID: 23319416
Opium; Adenocarcinoma; Cardia
3.  Association of tooth loss and oral hygiene with risk of gastric adenocarcinoma 
Introduction
Poor oral health and tooth loss have been proposed as possible risk factors for some chronic diseases, including gastric cancer. However only a small number of studies have tested these associations.
Method
We conducted a case-control study in Golestan Province, Iran, that enrolled 309 cases diagnosed with gastric adenocarcinoma (118 noncardia, 161 cardia, and 30 mixed-locations) and 613 sex, age and neighborhood matched controls. Data on oral health were obtained through physical examination and questionnaire including tooth loss, the number of decayed, missing, and filled teeth, and frequency of tooth brushing. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were obtained using conditional logistic regression models adjusted for potential confounders. Standard one degree-of-freedom linear trend test and a multiple degree of freedom global test of the effect of adding oral hygiene variables to the model were also calculated.
Results
Our results showed apparent associations between tooth loss and DMFT score with risk of gastric cancer, overall and at each anatomic subsite. However, these associations were not monotonic and were strongly confounded by age. The results also showed that subjects who brushed their teeth less than daily were at significantly higher risk for gastric cardia adenocarcinoma OR (95% CI) of 5.6 (1.6–19.3).
Discussion
We found evidence for an association between oral health and gastric cancer, but the non- monotonic association, the relatively strong effect of confounder adjustment, and inconsistent results across studies must temper the strength of any conclusions.
doi:10.1158/1940-6207.CAPR-12-0491
PMCID: PMC3644330  PMID: 23503651
Adenocarcinoma; Tooth loss; Oral health; Stomach
4.  The gastro-esophageal malignancies in Northern Iran research project: impact on the health research and health care systems in Iran 
Archives of Iranian medicine  2013;16(1):46-53.
Since 2000, considerable progress has been made in health research in Iran. An example of this progress has been the Gastro- Esophageal Malignancies in Northern Iran (GEMINI). 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 the initial goal. This project is one of the largest studies in the Middle East and North African region, has helped build and strengthen research capacity at both individual and institutional levels in Iran, and has provided international credibility to research institutes and the wider research system in Iran. The success of GEMINI reveals the feasibility of large-scale studies in developing countries and serves as a successful model not only for health research institutes within Iran, but also for research systems in other developing countries. The outcomes of the project are numerous, including establishment of research networks, development of efficient methods for planning and implementation of research projects, and introduction of methodologies for project management, data management and usage of health technology. Finally and perhaps most importantly, GEMINI is among the few projects that has had a significant impact on the attitudes and concerns of decision makers in the health sector in Iran. It signifies the importance of investment in human resources and has proved that health policies should be health-based rather than patient-based. Here we review the impact of GEMINI on the health research system and the broader health care system of Iran and put these into a more global perspective.
PMCID: PMC3659328  PMID: 23273237
research design; prospective studies; pilot projects; feasibility studies; planning techniques; methods; cancer epidemiology; gastroenterology
5.  InterSCOPE Study: Associations Between Esophageal Squamous Cell Carcinoma and Human Papillomavirus Serological Markers 
Background
The role of human papillomavirus (HPV) in the causation of esophageal squamous cell carcinoma is unclear. We examined the associations between esophageal squamous cell carcinoma and 28 centrally measured HPV serological markers in serum from six existing case–control studies conducted in regions with differing background risks of esophageal cancer.
Methods
We used centralized multiplex serology to test serum samples from 1561 case subjects and 2502 control subjects from six case–control studies for antibodies to the major HPV capsid protein (L1) and/or the early proteins E6 and/or E7 of eight high-risk, two low-risk, and four cutaneous HPV types. Study-specific odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using conditional logistic regression with adjustment for smoking, alcohol consumption, and other potential confounders. Pooled odds ratios and 95% confidence intervals were calculated using either a linear mixed-effects approach or a joint fixed-effects approach. All statistical tests were two-sided.
Results
We found statistically significant associations between esophageal squamous cell carcinoma and antibodies to E6 for HPV16 (OR = 1.89, 95% CI = 1.09 to 3.29, P = .023) and HPV6 (OR = 2.53, 95% CI = 1.51 to 4.25, P < .001) but not for other tested HPV types. There were no statistically significant associations between esophageal squamous cell carcinoma and antibodies to E7 for any of the tested HPV types. Simultaneous seropositivity for HPV16 E6 and E7 was rare (four case subjects, two control subjects; OR = 5.57, 95% CI = 0.90 to 34.35; P = .064). We also found statistically significant associations between esophageal squamous cell carcinoma and capsid antibodies for the high-risk mucosal type HPV33 L1 (OR = 1.30, 95% CI = 1.00 to 1.69; P = .047) and the low-risk mucosal types HPV6 (OR = 1.22, 95% CI = 1.05 to 1.42; P = .010) and HPV11 (OR = 1.30, 95% CI = 1.09 to 1.56, P = .0036).
Conclusions
We found limited serological evidence of an association between esophageal squamous cell carcinoma and HPV in the populations studied. Although HPV does not appear to be an important risk factor for esophageal squamous cell carcinoma, we cannot exclude the possibility that certain HPV types may be involved in a small subset of cancers.
doi:10.1093/jnci/djr499
PMCID: PMC3260131  PMID: 22228147
6.  Is Opium a Real Risk Factor for Esophageal Cancer or Just a Methodological Artifact? Hospital and Neighborhood Controls in Case-Control Studies 
PLoS ONE  2012;7(3):e32711.
Background
Control selection is a major challenge in epidemiologic case-control studies. The aim of our study was to evaluate using hospital versus neighborhood control groups in studying risk factors of esophageal squamous cell carcinoma (ESCC).
Methodology/Principal Findings
We compared the results of two different case-control studies of ESCC conducted in the same region by a single research group. Case definition and enrollment were the same in the two studies, but control selection differed. In the first study, we selected two age- and sex-matched controls from inpatient subjects in hospitals, while for the second we selected two age- and sex-matched controls from each subject's neighborhood of residence. We used the test of heterogeneity to compare the results of the two studies. We found no significant differences in exposure data for tobacco-related variables such as cigarette smoking, chewing Nass (a tobacco product) and hookah (water pipe) usage, but the frequency of opium usage was significantly different between hospital and neighborhood controls. Consequently, the inference drawn for the association between ESCC and tobacco use did not differ between the studies, but it did for opium use. In the study using neighborhood controls, opium use was associated with a significantly increased risk of ESCC (adjusted OR 1.77, 95% CI 1.17–2.68), while in the study using hospital controls, this was not the case (OR 1.09, 95% CI 0.63–1.87). Comparing the prevalence of opium consumption in the two control groups and a cohort enrolled from the same geographic area suggested that the neighborhood controls were more representative of the study base population for this exposure.
Conclusions/Significance
Hospital and neighborhood controls did not lead us to the same conclusion for a major hypothesized risk factor for ESCC in this population. Our results show that control group selection is critical in drawing appropriate conclusions in observational studies.
doi:10.1371/journal.pone.0032711
PMCID: PMC3291619  PMID: 22396792
7.  Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study 
Objective To investigate the association between tea drinking habits in Golestan province, northern Iran, and risk of oesophageal squamous cell carcinoma.
Design Population based case-control study. In addition, patterns of tea drinking and temperature at which tea was drunk were measured among healthy participants in a cohort study.
Setting Golestan province, northern Iran, an area with a high incidence of oesophageal squamous cell carcinoma.
Participants 300 histologically proved cases of oesophageal squamous cell carcinoma and 571 matched neighbourhood controls in the case-control study and 48 582 participants in the cohort study.
Main outcome measure Odds ratio of oesophageal squamous cell carcinoma associated with drinking hot tea.
Results Nearly all (98%) of the cohort participants drank black tea regularly, with a mean volume consumed of over one litre a day. 39.0% of participants drank their tea at temperatures less than 60°C, 38.9% at 60-64°C, and 22.0% at 65°C or higher. A moderate agreement was found between reported tea drinking temperature and actual temperature measurements (weighted κ 0.49). The results of the case-control study showed that compared with drinking lukewarm or warm tea, drinking hot tea (odds ratio 2.07, 95% confidence interval 1.28 to 3.35) or very hot tea (8.16, 3.93 to 16.9) was associated with an increased risk of oesophageal cancer. Likewise, compared with drinking tea four or more minutes after being poured, drinking tea 2-3 minutes after pouring (2.49, 1.62 to 3.83) or less than two minutes after pouring (5.41, 2.63 to 11.1) was associated with a significantly increased risk. A strong agreement was found between responses to the questions on temperature at which tea was drunk and interval from tea being poured to being drunk (weighted κ 0.68).
Conclusion Drinking hot tea, a habit common in Golestan province, was strongly associated with a higher risk of oesophageal cancer.
doi:10.1136/bmj.b929
PMCID: PMC3269898  PMID: 19325180
8.  Extremely High Tp53 Mutation Load in Esophageal Squamous Cell Carcinoma in Golestan Province, Iran 
PLoS ONE  2011;6(12):e29488.
Background
Golestan Province in northeastern Iran has one of the highest incidences of esophageal squamous cell carcinoma (ESCC) in the world with rates over 50 per 100,000 person-years in both sexes. We have analyzed TP53 mutation patterns in tumors from this high-risk geographic area in search of clues to the mutagenic processes involved in causing ESCC.
Methodology/Principal Findings
Biopsies of 119 confirmed ESCC tumor tissue from subjects enrolled in a case-control study conducted in Golestan Province were analyzed by direct sequencing of TP53 exons 2 through 11. Immunohistochemical staining for p53 was carried out using two monoclonal antibodies, DO7 and 1801. A total of 120 TP53 mutations were detected in 107/119 cases (89.9%), including 11 patients with double or triple mutations. The mutation pattern was heterogeneous with infrequent mutations at common TP53 “hotspots” but frequent transversions potentially attributable to environmental carcinogens forming bulky DNA adducts, including 40% at bases known as site of mutagenesis by polycyclic aromatic hydrocarbons (PAHs). Mutations showed different patterns according to the reported temperature of tea consumption, but no variation was observed in relation to ethnicity, tobacco or opium use, and alcoholic beverage consumption or urban versus rural residence.
Conclusion/Significance
ESCC tumors in people from Golestan Province show the highest rate of TP53 mutations ever reported in any cancer anywhere. The heterogeneous mutation pattern is highly suggestive of a causative role for multiple environmental carcinogens, including PAHs. The temperature and composition of tea may also influence mutagenesis.
doi:10.1371/journal.pone.0029488
PMCID: PMC3246475  PMID: 22216294
9.  Accuracy and Cut-Off Values of Pepsinogens I, II and Gastrin 17 for Diagnosis of Gastric Fundic Atrophy: Influence of Gastritis 
PLoS ONE  2011;6(10):e26957.
Background
To establish optimal cutoff values for serologic diagnosis of fundic atrophy in a high-risk area for oesophageal squamous cell carcinoma and gastric cancer with high prevalence of Helicobacter pylori (H. pylori) in Northern Iran, we performed an endoscopy-room-based validation study.
Methods
We measured serum pepsinogens I (PGI) and II (PGII), gastrin 17 (G-17), and antibodies against whole H. pylori, or cytotoxin-associated gene A (CagA) antigen among 309 consecutive patients in two major endoscopy clinics in northeastern Iran. Updated Sydney System was used as histology gold standard. Areas under curves (AUCs), optimal cutoff and predictive values were calculated for serum biomarkers against the histology.
Results
309 persons were recruited (mean age: 63.5 years old, 59.5% female). 84.5% were H. pylori positive and 77.5% were CagA positive. 21 fundic atrophy and 101 nonatrophic pangastritis were diagnosed. The best cutoff values in fundic atrophy assessment were calculated at PGI<56 µg/l (sensitivity: 61.9%, specificity: 94.8%) and PGI/PGII ratio<5 (sensitivity: 75.0%, specificity: 91.0%). A serum G-17<2.6 pmol/l or G-17>40 pmol/l was 81% sensitive and 73.3% specific for diagnosing fundic atrophy. At cutoff concentration of 11.8 µg/l, PGII showed 84.2% sensitivity and 45.4% specificity to distinguish nonatrophic pangastritis. Exclusion of nonatrophic pangastritis enhanced diagnostic ability of PGI/PGII ratio (from AUC = 0.66 to 0.90) but did not affect AUC of PGI. After restricting study samples to those with PGII<11.8, the sensitivity of using PGI<56 to define fundic atrophy increased to 83.3% (95%CI 51.6–97.9) and its specificity decreased to 88.8% (95%CI 80.8–94.3).
Conclusions
Among endoscopy clinic patients, PGII is a sensitive marker for extension of nonatrophic gastritis toward the corpus. PGI is a stable biomarker in assessment of fundic atrophy and has similar accuracy to PGI/PGII ratio among populations with prevalent nonatrophic pangastritis.
doi:10.1371/journal.pone.0026957
PMCID: PMC3204997  PMID: 22066020
10.  Socio-economic status and oesophageal cancer: results from a population-based case–control study in a high-risk area 
Background Cancer registries in the 1970s showed that parts of Golestan Province in Iran had the highest rate of oesophageal squamous cell carcinoma (OSCC) in the world. More recent studies have shown that while rates are still high, they are approximately half of what they were before, which might be attributable to improved socio-economic status (SES) and living conditions in this area. We examined a wide range of SES indicators to investigate the association between different SES components and risk of OSCC in the region.
Methods Data were obtained from a population-based case–control study conducted between 2003 and 2007 with 300 histologically proven OSCC cases and 571 matched neighbourhood controls. We used conditional logistic regression to compare cases and controls for individual SES indicators, for a composite wealth score constructed using multiple correspondence analysis, and for factors obtained from factors analysis.
Results We found that various dimensions of SES, such as education, wealth and being married were all inversely related to OSCC. The strongest inverse association was found with education. Compared with no education, the adjusted odds ratios (95% confidence intervals) for primary education and high school or beyond were 0.52 (0.27–0.98) and 0.20 (0.06–0.65), respectively.
Conclusions The strong association of SES with OSCC after adjustment for known risk factors implies the presence of yet unidentified risk factors that are correlated with our SES measures; identification of these factors could be the target of future studies. Our results also emphasize the importance of using multiple SES measures in epidemiological studies.
doi:10.1093/ije/dyp195
PMCID: PMC2720396  PMID: 19416955
Oesophageal cancer; socio-economic status; case–control; epidemiology; Iran; factor analysis; correspondence analysis
11.  Patterns of food and nutrient consumption in northern Iran, a high-risk area for esophageal cancer 
Nutrition and cancer  2009;61(4):475-483.
Objectives
To investigate patterns of food and nutrient consumption in Golestan province, a high-incidence area for esophageal cancer (EC) in northern Iran.
Methods
Twelve 24-hour dietary recalls were administered during a one year period to 131 healthy participants in a pilot cohort study. We compare here nutrient intake in Golestan with Recommended Daily Allowances (RDAs) and Lowest Threshold Intakes (LTIs). We also compare the intake of 27 food groups and nutrients among several population subgroups, using mean values from the twelve recalls.
Results
Rural women had a very low level of vitamin intake, which was even lower than LTIs (P < 0.01). Daily intake of vitamins A and C was lower than LTI in 67% and 73% of rural women, respectively. Among rural men, the vitamin intakes were not significantly different from LTIs. Among urban women, the vitamin intakes were significantly lower than RDAs, but were significantly higher than LTIs. Among urban men, the intakes were not significantly different from RDAs. Compared to urban dwellers, intake of most food groups and nutrients, including vitamins, was significantly lower among rural dwellers. In terms of vitamin intake, no significant difference was observed between Turkmen and non-Turkmen ethnics.
Conclusions
The severe deficiency in vitamin intake among women and rural dwellers and marked differences in nutrient intake between rural and urban dwellers may contribute to the observed epidemiological pattern of EC in Golestan, with high incidence rates among women and people with low socioeconomic status, and the highest incidence rate among rural women.
doi:10.1080/01635580902803735
PMCID: PMC2796961  PMID: 19838919
esophageal cancer; Iran; Caspian Littoral; Golestan: Turkmen; diet record
12.  Tooth loss and lack of regular oral hygiene are associated with higher risk of esophageal squamous cell carcinoma 
We tested the association between tooth loss and oral hygiene and the risk of esophageal squamous cell carcinoma (ESCC) in people living in a high risk area of Iran. We used a case-control study of pathologically-confirmed ESCC cases (N=283) and controls (N=560) matched on sex, age, and neighborhood. Subjects with ESCC had significantly more decayed, missing, or filled teeth with a median (interquartile range) of 31 (23-32) compared to controls 28 (2-32) (P=0.0045). And subjects with ESCC were significantly more likely than controls to fail to practice regular oral hygiene, 78% versus 58%. In multivariate adjusted conditional logistic regression models having 32 decayed, missing, or filled teeth compared to ≤15 conferred an OR (95% CI) of 2.10 (1.19-3.70). Compared to daily tooth brushing, practicing no regular oral hygiene conferred an OR (95% CI) of 2.37 (1.42-3.97). Restricting the analysis to subjects that had never smoked tobacco did not materially alter these results. We found significant associations between two markers of poor oral hygiene, a larger number of decayed, missing, or filled teeth and lack of daily tooth brushing, and risk of ESCC in a population at high risk for ESCC where many cases occur in never smokers. Our results are consistent with several previous analyses in other high risk populations.
doi:10.1158/1055-9965.EPI-08-0558
PMCID: PMC2586052  PMID: 18990747
Tooth loss; tooth brushing; esophagus; squamous; cancer

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