Patterns of food and nutrient consumption in northern Iran, a high-risk area for esophageal cancer

Ethnic Disparities in Major Adverse Cardiac and Cerebrovascular Events (MACCEs) and Postoperative Outcomes Following Coronary Artery Bypass in Northeastern Iran (2007-2016)

BACKGROUND

Turkmens are an ethnic group mainly living in northeastern Iran. Despite previous studies on coronary artery bypass surgery (CABG) outcomes among different ethnicities, the effect of Turkmen ethnicity on outcomes of CABG surgery is still unknown. We aimed to assess the association between Turkmen ethnicity and postoperative outcomes following CABG.

METHODS

We used the CABG data from two heart centers in northeastern Iran between 2007 and 2016. We included adult patients undergoing CABG surgery. The study outcomes were in-hospital major adverse cardiac and cerebrovascular events (MACCEs), consisting of myocardial infarction (MI), stroke, and cardiovascular death, and postoperative outcomes, including postoperative arrhythmia, acute atrial fibrillation (AF), major bleeding, and acute renal failure (ARF).

RESULTS

Over the course of one decade, 3632 patients, with an average age (standard deviation) of 59.0 (9.8) years, were studied. Of these, 3,331 patients were of non-Turkmen ethnicity, and 301 patients were Turkmens. According to adjusted analysis, ethnicity was not associated with MACCEs (OR: 1.15, 95 % CI: 0.61, 2.16; P=0.663), postoperative arrhythmia (OR: 1.10, 95% CI: 0.78, 1.54; P=0.588), acute AF (OR: 1.17, 95 % CI: 0.83, 1.66; P=0.359), major bleeding (OR: 1.21, 95 % CI: 0.55, 2.67; P=0.636), or ARF (OR: 2.60, 95 % CI: 0.60, 11.75, P=0.224).

CONCLUSION

This study found that despite ethnic disparity and preoperative differences, Turkmen ethnicity was not associated with in-hospital MACCEs, AF, major bleeding, or ARF after coronary artery bypass.

Comparing food consumption during the COVID-19 pandemic: analysis of household income and expenditure survey data in Iran

BACKGROUND

On March 11, 2020, the WHO declared the outbreak of the infectious disease COVID-19 as a pandemic. The health strategies of nations lead to possible changes in lifestyle and increase poor eating habits. Hence, the purpose of this study is to compare food consumption during COVID-19 pandemic in Iran.

METHODS

This cross-sectional study used secondary data from the Households Income and Expenditure Survey (HIES) conducted annually by the Statistical Centre of Iran. Food cost data of HIES included the amount of all food items in household food baskets during the last month. Then, they were classified into six food groups to evaluate their energy intake. The consequence of food consumption was analyzed as a function of socioeconomic status (SES) variables and residence pre- and post-COVID-19 pandemic.

RESULTS

In total, 75,885 households (83.5% male) were included in the study. Among the population of urban and rural areas as well as in different SES categories, people tended to increase the consumption of meat (P < 0.05) and fresh foods, especially vegetable groups (P < 0.001) and decrease the consumption of fruit (P < 0.001), fat and sweets groups (P < 0.05) and also in energy intake (P < 0.05). Macronutrient changes were different in the category of SES, urban and rural.

CONCLUSION

Our study indicated that the COVID-19 pandemic had different effects on food groups, energy and macronutrients consumption, which could be due to possible changes in food patterns as a result of the pandemic.

Association between dietary fat intake and colorectal cancer: A multicenter case-control study in Iran

The evolving trends in colorectal cancer (CRC) as one of the most common malignancies worldwide, have likely been influenced by the implementation of screening programs and changes in lifestyle habits. Changing lifestyle, including the shift in diet composition with higher fat, sugar, and animal-source foods intake, led to an increasing burden of CRC in countries undergoing rapid socioeconomic improvement. Results for the link between specific fatty acids (FAs) and CRC are generally inconclusive and more limited in developing countries than elsewhere. This study aims to investigate the association between FA intakes and CRC and its anatomical subsites in a large Iranian case-control study. A food frequency questionnaire was used to collect information on dietary intake in 865 cases and 3206 controls. We conducted multivariate logistic regression models to calculate the odds ratio (OR) and 95% confidence interval (CI). We found positive association between CRC and high intake of dietary total fat (OR highest quartile Q4 = 1.77, 95% CI = 1.32-2.38), cholesterol (ORQ4 = 1.58, 95% CI = 1.22-2.05), and palmitoleic acid (ORQ4 = 2.16, 95% CI = 1.19, 3.91), and an inverse association with high intake of dietary heptanoic acid (ORQ4 = 0.33, 95% CI = 0.14, 0.79) and low intake of palmitic acid (OR lowest quartile Q2 = 0.53, 95% CI = 0.31-0.88). None of the fat variables were associated with rectal cancer. Our study suggests that the recommendation of limited consumption of fats may decrease the risk of CRC among the Iranian population.

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.

Dietary and Environmental Determinants of Oesophageal Cancer in Arsi Zone, Oromia, Central Ethiopia: A Case-Control Study

PURPOSE

Oesophageal cancer is ranked 5th of all types of malignancies in Ethiopia and highly prevalent in the Arsi Zone. However, no study was conducted to elucidate the dietary and environmental determinants of oesophageal cancer in the Arsi Zone.

METHODS

A matched case-control study was conducted from June 1, 2019, to June 30, 2020. A total of 104 cases and 208 controls were interviewed. Data were collected using food frequency questionnaires (structured questionnaires). Binary and multiple logistic regression analyses were conducted to check the association between independent and dependent variables. Adjusted odds ratios and the corresponding 95% confidence intervals were estimated for the strength of association. Statistical significance was declared at a P-value of <0.05.

RESULTS

In multivariable logistic regression, drinking very hot coffee (AOR=5.1,[95% CI: (1.95, 13.71), drinking large volume of coffee (AOR=4.9, [95% CI: (2.03, 12.17), very hot porridge (AOR= 3.1,[95% CI: (1.38,7.03) and eating porridge fast (AOR=7.0, [95% CI: (2.48, 20.14), low intake of dairy products (AOR=6.0, [95% CI: (2.29, 15.95), cooking food in sleeping room (AOR=3.7, [95% CI: (1.22, 11.39), exposure to x-ray (AOR=9.4,[95% CI: (3.94, 22.82), nonalcohol homemade drinks (AOR=5.4,[95% CI: (1.97, 15.14), use of chemical containers (AOR=3.4, [95% CI: (1.48, 8.23) were determinants of oesophageal cancer.

CONCLUSION

Coffee temperature, coffee drinking volume, porridge consumption temperature, porridge consumption speed, dairy products intake patterns, food cooking place, x-ray exposure, nonalcohol homemade drink, and use of chemical containers were independent determinants of the increased risk of oesophageal cancer in the study community.

Perceived role of hot food in the pathogenesis of oesophageal cancer: a qualitative study in the Arsi Zone, Oromia, Central Ethiopia

Observational studies in Ethiopia have identified a positive association between hot wheat porridge consumption and oesophageal carcinoma. However, a single dietary intake cannot be a sufficient predictor of cancer among populations that have diverse dietary practices. The present study was carried out to explore the community's perspectives on the role of hot foods in the pathogenesis of oesophageal cancer in Ethiopia. Focus group discussions were conducted from May to August 2019 among purposefully selected 112 participants. Data were collected by using open-ended questions; memo writing, audio recordings and photo pictures. All tape-recorded interviews were transcribed verbatim and inductively coded using Atlas.ti Version 7.0.71 software. Finally, the analysis was performed according to the standard thematic framework analysis techniques. The finding showed that hot foods (porridge, coffee and soup) consumption patterns were perceived as the principal dietary risk of oesophageal cancer. Cooking in unventilated rooms, monotonous cereal-based foods, poor vegetable, and fruit intake, not taking milk with porridge, eating fast, swallowing large bolus of hot porridge and exposure to carcinogens in foods were regarded as predisposing dietary practices to oesophageal carcinoma. Socio-demographic, economic and cultural backgrounds were reported as the underlying risk factors associated with oesophageal cancer. There was a strong perception within the community that oesophageal cancer is linked to several but sequentially interlinked dietary and related practices. Cumulative thermal injuries from the consumptions of hot food could be the immediate dietary risk factors associated with increased risk of oesophageal cancer.

Trends in the Incidence of Stomach Cancer in Golestan Province, a High-risk Area in Northern Iran, 2004-2016

BACKGROUND

We aimed to present the temporal and geographical trends in the incidence of stomach cancer in the Golestan province, a high-risk area in Northern Iran.

METHODS

This study was conducted on stomach cancer cases registered in the Golestan Population-based Cancer Registry (GPCR) during 2004-2016. Age-standardized incidence rates (ASRs) per 100000 person-years were calculated. The Joinpoint regression analysis was used to calculate the average annual percent changes (AAPC). We also calculated the contribution of population aging, population size and risk to the overall changes in incidence rates.

RESULTS

Overall, 2964 stomach cancer patients were registered. The ASR of stomach cancer was significantly higher in men (26.9) than women (12.2) (P<0.01). There was a significant decreasing trend in incidence of stomach cancer in men (AAPC=-1.80, 95% CI: -3.30 to-0.28; P=0.02). We found a higher ASR of stomach cancer in the rural (21.4) than urban (18.1) (P=0.04) population, as well as a significant decreasing trend in its rates (AAPC=-2.14, 95% CI: -3.10to-1.17; P<0.01). The number of new cases of stomach cancer increased by 22.33% (from 215 in 2004 to 263 in 2016), of which 18.1%, 25.1% and -20.9% were due to population size, population aging and risk, respectively. Our findings suggest a higher rate for stomach cancer in eastern areas.

CONCLUSION

We found high incidence rates as well as temporal and geographical diversities in ASR of stomach cancer in Golestan, Iran. Our results showed an increase in the number of new cases, mainly due to population size and aging. Further studies are warranted to determine the risk factors of this cancer in this high-risk population.

Associations of dietary carbohydrate and salt consumption with esophageal cancer risk: a systematic review and meta-analysis of observational studies

Context

Evidence has shown that essential nutrients are highly correlated with the occurrence of esophageal cancer (EC). However, findings from observational studies on the associations between dietary carbohydrate, salt consumption, and the risk of EC remain controversial.

Objective

The aim of this study was to conduct a systematic review and meta-analysis to confirm the associations of dietary carbohydrate and salt consumption with EC risk.

Data Source

Various electronic databases (PubMed, MEDLINE, Embase, Google Scholar, Cochrane Library, Chinese Electronic Periodical Services, and China Knowledge Resource Integrated) were searched up until January 31, 2019.

Data Extraction

Data related to patient characteristics and study characteristics were extracted by 2 independent reviewers. The risk ratio reported as relative risk (RR) or odds ratio (OR) was extracted, and random-effects models were performed to estimate the summary risk ratio.

Results

In total, 26 studies were included in this analysis, of which 12 studies, including 11 case-control studies and 1 cohort study, examined dietary carbohydrates, and 18 studies, including 16 case-control studies and 2 cohort studies, examined dietary salt. The pooled OR showed that dietary carbohydrate intake was inversely related to EC risk (OR = 0.62; 95% confidence interval [CI], 0.50–0.77), but positive correlations between dietary salt intake and the risk of EC were supported by the recruited case-control studies (OR = 1.97; 95% CI, 1.50–2.61) and cohort studies (RR = 1.04; 95% CI, 1.00–1.08).

Conclusions

Salt is an essential nutrient for body functions and biochemical processes. Providing health education and management regarding proper use of salt in daily foods and labeling the amount of sodium in manufactured products to reduce the risk of developing EC should be more appropriately performed in the general population.

Physiological risk factors for cardiovascular disease in middle-aged (40-60 year) adults and their association with dietary intake, Northern Iran

Background

Considering the importance of healthy diet in the protection of cardiovascular diseases (CVD), this research aimed to assess the physiological risk factors for CVD in middle-aged adults and their association with dietary intake in the north of Iran.

Methods

In this cross-sectional study conducted in the years 2016-2017 among the adults aged 40-60 years living in Amirkola, Babol, the participants´ physical activity, dietary intake, body mass index, fat mass, blood pressure, fasting blood glucose and serum lipid profile were reported. The International Physical Activity Questionnaire was used to assess physical activity and a structured 24-hour food-recall questionnaire was used to assess the participants´ dietary intake. Consumed foods and beverages on two separate days were analyzed and transcribed in 10 food groups (gram).

Results

Two hundred and ninety-one persons (96.7%) had complete participation, 96.2% with at least one CVD risk factor and 75.9% had overweight or obesity; 33% with hypertension; 6.2% had high fasting blood glucose; 64.6% with hypercholesterolemia, 47.8% had hypertriglyceridemia, and 8.9% with low HDL. Mean daily intake values of carbohydrate, protein and fat were all higher than dietary reference intakes for adults. Physical activity less than 1500 MET-minutes per week was significantly associated with having three or more physiological risk factors for CVD [adjusted odds ratio: 2.04 (1.08-3.85)] (P=0.029).

Conclusion

Most of the middle-aged adults in this region had at least one of the physiological risk factors for CVD and daily intakes of carbohydrate and protein were higher than dietary reference intakes (DRIs) for adults.

Burden of esophageal cancer in Iran during 1995-2015: Review of findings from the Global Burden of Disease studies

Background: Iran is located in Asian esophageal cancer belt, with age-standardized incidence rate (ASR) of approximately 7 per 100,000 for both men and women. To provide potential solution recommendations for achieving accurate estimations regarding the burden of the disease in Iran, we designed a study to assess the burden of esophageal cancer in Iran during 1995-2015 by collecting data from the Global Burden of Disease studies.

Methods: Data were extracted from the Global Burden of Disease (GBD) during 1995-2015, which were published by the Institute for Health Metrics and Evaluation. For this purpose, disability adjusted life years (DALYs), incidence, and prevalence rate were applied to report burden of esophageal cancer based on gender and age group in Iran during 1995-2015. The Cochran-Armitage and t test were used to assess statistical significance. Stata Version 13 and Excel 2016 were used for data analysis.

Results: During 1995-2015, in total, 304 102 DALYs (179 562 for males vs. 124 540 for females) were attributed to esophageal cancer in Iran. In both genders and all ages, the number of DALYs increased significantly from 45 018 in 1995 to 74 399 in 2015.

Conclusion: Esophageal cancer is still a public health issue in Iran. Most of DALYs were due to years of life lost (YLL), suggesting the need for prevention, early detection, and screening programs. P-value was statistically significant just between male and female groups (p<0.05).

The Relation of HPV Infection and Expression of p53 and p16 Proteins in Esophageal Squamous Cells Carcinoma

GOAL: To investigate the HPV prevalence and characterize the expression of potential molecular surrogate markers of HPV infection in esophageal squamous cell carcinoma.

MATERIALS AND METHODS: The prevalence of HPV in individuals with and without esophageal cancer (EC) was determined by using multiplex PCR; p16 and p53 protein levels were assessed by immunohistochemistry (IHC).

RESULTS: High-risk HPV (hr-HPV) was found in the same frequency (13.8%) in esophageal squamous cell carcinoma (ESCC) and in healthy individuals. The p53 expression was positive in 67.5% of tumor tissue, 20.0% of adjacent non-tumoral tissue and 1.8% of normal esophageal tissue. p16 was positive in 11.6% of esophageal cancer cases and 4.7% of adjacent non-tumoral tissue. p16 was undetectable among control group samples. p53 and p16 levels were not significantly associated with the HPV status.

CONCLUSIONS: These results suggest that hr-HPV types are not associated with the development of ESCC and that p53 and p16 protein expression have no relationship with HPV infection in normal or cancerous esophagus.

The low IGFBP-3 level is associated with esophageal cancer patients: a meta-analysis

Background

Esophageal cancer was a vital cause of cancer-related mortality worldwide, and the insulin-like growth factor-binding proteins (IGFBPs) has been proved to be an important factor of multiple types of tumors. There is a controversy that whether the IGFBP-3 level is associated with the clinical pathological characteristics and overall survival of esophageal cancer patients. Herein, we aimed to comprehensively assess the association between the low IGFBP-3 level and the risk, overall survival and clinical pathological characteristics of esophageal cancer.

Method

We conducted a meta-analysis using seven eligible studies. The overall odds ratios (OR)/relative risk (RR) and their corresponding 95% confidence interval (CI) were calculated for each parameter.

Results

For the risk of esophageal cancer, the OR was 2.342 (p = 0.000), indicating that individuals with lower IGFBP-3 level were more likely to suffer from esophageal cancer, compared to those with relatively high IGFBP-3 level. With respect to the 3-year survival rate, the RR was 2.163 (p = 0.027), which demonstrated that esophageal cancer patients with low IGFBP-3 level had significantly lower 3-year survival rate; in terms of clinical pathological characteristics, significantly lower IGFBP-3 level was found for patients in all categories; for survival status, patients in low IGFBP-3 level are more likely to be in the dead survival status (OR = 4.480, p = 0.000).

Conclusion

Our meta-analysis suggests that for esophageal cancer, the low IGFBP-3 level is associated with high cancer risk, poor prognosis, and unfavorable tumor stage and metastasis.

The Combined Effects of Healthy Lifestyle Behaviors on All-Cause Mortality: The Golestan Cohort Study

BACKGROUND

Most studies that have evaluated the association between combined lifestyle factors and mortality outcomes have been conducted in populations of developed countries.

OBJECTIVES

The aim of this study was to examine the association between combined lifestyle scores and risk of all-cause and cause-specific mortality for the first time among Iranian adults.

METHODS

The study population included 50,045 Iranians, 40 - 75 years of age, who were enrolled in the Golestan Cohort Study, between 2004 and 2008. The lifestyle risk factors used in this study included cigarette smoking, physical inactivity, and Alternative Healthy Eating Index. The lifestyle score ranged from zero (non-healthy) to 3 (most healthy) points. From the study baseline up to analysis, a total of 4691 mortality cases were recorded. Participants with chronic diseases at baseline, outlier reports of calorie intake, missing data, and body mass index of less than 18.5 were excluded from the analyses. Cox regression models were fitted to establish the association between combined lifestyle scores and mortality outcomes.

RESULTS

After implementing the exclusion criteria, data from 40,708 participants were included in analyses. During 8.08 years of follow-up, 3,039 cases of all-cause mortality were recorded. The adjusted hazard ratio of a healthy lifestyle score, compared with non-healthy lifestyle score, was 0.68 (95% CI: 0.54, 0.86) for all-cause mortality, 0.53 (95% CI: 0.37, 0.77) for cardiovascular mortality, and 0.82 (95% CI: 0.53, 1.26) for mortality due to cancer. When we excluded the first two years of follow up from the analysis, the protective association between healthy lifestyle score and cardiovascular death did not change much 0.55 (95% CI: 0.36, 0.84), but the inverse association with all-cause mortality became weaker 0.72 (95% CI: 0.55, 0.94), and the association with cancer mortality was non-significant 0.92 (95% CI: 0.58, 1.48). In the gender-stratified analysis, we found an inverse strong association between adherence to healthy lifestyle and mortality from all causes and cardiovascular disease in either gender, but no significant relationship was seen with mortality from cancer in men or women. Stratified analysis of BMI status revealed an inverse significant association between adherence to healthy lifestyle and mortality from all causes, cardiovascular disease and cancer among non-obese participants.

CONCLUSION

We found evidence indicating that adherence to a healthy lifestyle, compared to non-healthy lifestyle, was associated with decreased risk of all-cause mortality and mortality from cardiovascular diseases in Iranian adults.

Esophageal Cancer in Golestan Province, Iran: A Review of Genetic Susceptibility and Environmental Risk Factors

Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor that is typically diagnosed only when the tumor has gained remarkable size, extended to peripheral tissues, and led to dysphagia. Five-year survival of advanced cancer is still very poor (19%), even with improved surgical techniques and adjuvant chemoradiation therapy. Therefore, early detection and prevention are the most important strategies to reduce the burden of ESCC. Our review will focus on the studies conducted in Golestan province, an area with a high prevalence of ESCC in northern Iran. We review three aspects of the research literature on ESCC: epidemiological features, environmental factors (including substance abuse, environmental contaminants, dietary factors, and human papillomavirus [HPV]), and molecular factors (including oncogenes, tumor suppressor genes, cell cycle regulatory proteins, and other relevant biomarkers). Epidemiological and experimental data suggest that some chemicals and lifestyle factors, including polycyclic aromatic hydrocarbons (PAHs), cigarette smoking, opium use, and hot tea drinking are associated with the development of ESCC in Golestan. HPV infects the esophageal epithelium, but so far, no firm evidence of its involvement in esophageal carcinogenesis has been provided. Some of these factors, notably hot tea drinking, may render the esophageal mucosa more susceptible to injury by other carcinogens. There are few studies at molecular level on ESCC in Golestan. Increasing awareness about the known risk factors of ESCC could potentially reduce the burden of ESCC in the region. Further studies on risk factors, identifying high risk populations, and early detection are needed.

The promise of PD-1 inhibitors in gastro-esophageal cancers: microsatellite instability vs. PD-L1

Preliminary clinical studies of anti-programmed cell death-1 (anti-PD-1) therapy in gastro-esophageal cancers have suggested promising single-agent activity. In patients who received prior treatment for advanced disease, pembrolizumab has been associated with a response rate of 20% in programmed cell death-1 ligand 1 (PD-L1)-positive tumors, and nivolumab with a response rate of 12% in unselected tumors. Both agents yielded a median duration of response lasting ~6-7 months. PD-L1 expression and microsatellite instability (MSI) have emerged as potential predictive markers for PD-1/PD-L1 blockade. PD-L1 expression in tumor cells and in immune cells within the tumor microenvironment has been detected in 14-24% and ~35% of patients with gastro-esophageal cancer, respectively. PD-L1 tumor cell expression appears to be more common in Epstein-Barr virus (EBV)-positive gastric cancers (GCs) and has been associated with an increased density of tumor-infiltrating lymphocytes (TIL). To date, data are too sparse to determine whether PD-L1 expression predicts efficacy of anti-PD-1 therapy in gastro-esophageal cancer, but data from other tumor types have not been consistent regarding its predictive value. MSI occurs in 10-20% of gastro-esophageal cancers and arises from deficient mismatch repair (MMR). MSI is highly correlated with non-synonymous mutation burden, as well as a dense accumulation of TILs. MSI has been associated with improved response to anti-PD-1 therapy in gastrointestinal cancers. Multiple studies are ongoing which examine therapeutic blockade of the PD-1/PD-L1 axis in unselected patients with gastro-esophageal cancer, as well as patients whose tumors express PD-L1 or exhibit MSI. These studies will clarify their activity in this disease and potentially can determine whether identify a strong predictive biomarker can be identified. Checkpoint inhibition is also being studied in combination with curative-intent chemo (radio) therapy and surgery.

Pars cohort study of non-communicable diseases in Iran: protocol and preliminary results

OBJECTIVES

The pars cohort study (PCS) is a 10-year cohort study aiming to investigate the burden and the major risk factors of non-communicable diseases, and to establish a setting to launch interventions for prevention of these diseases and controlling their risk factors.

METHODS

All inhabitants of Valashahr district in South of Iran, aged 40-75 years, were invited to undergo interviews and physical examination, and to provide biological samples. A total of 9264 invitees accepted to participate in the study (95 % participation rate) and were recruited from 2012 to 2014. Active follow-up was also carried out after 12 months.

RESULTS

About 46 % of participants were male and 54 % were female. About 14.0 % of the participants were current smokers and 8.4 % were ever opium users. The prevalence of overweight and obesity were 37.3 and 18.2 %, respectively. The prevalence of hypertension was 26.9 %. A total of 49 participants died during a median follow-up of one year.

CONCLUSIONS

PCS with its large scale and wealth of socio-economic and medical data can be a unique platform for studying the etiology of non-communicable diseases and effective interventions in Iran.

Hypertension and mortality in the Golestan Cohort Study: A prospective study of 50 000 adults in Iran

High blood pressure has been the second most important determinant of disease burden in Iran since the 1990s. Despite well-recognized evidence on the association of high blood pressure and mortality in other countries, this relationship has not been fully investigated in the demographic setting of Iran. The current study is the first large-scale longitudinal study of this association in Iran. Briefly, 50 045 subjects between 40 and 75 years of age have been recruited and followed. Blood pressure measurements were carried out at baseline. Causes of death were reported and verified by verbal autopsy throughout the follow-up period. The outcomes of interest were all-cause deaths and deaths due to ischemic heart disease (IHD) or stroke. Cox proportional hazards regression models were used to estimate hazard ratios (HRs). A total of 46 674 subjects free from cardiovascular disease at baseline were analyzed. Absolute mortality rates increased along with increasing systolic or diastolic blood pressure above 120 and 80 mm Hg, respectively. Adjusted HRs (95% confidence intervals) for each 20 mm Hg increase in systolic blood pressure in all age groups were 1.18 (1.13-1.23) for all-cause mortality, 1.21 (1.13-1.31) for deaths due to IHD and 1.50 (1.39-1.63) for deaths due to stroke. Unadjusted and adjusted HRs were higher in younger subjects and decreased with increasing age of the participants. High blood pressure is a serious threat to the health of Iranians. The entire health-care system of Iran should be involved in a comprehensive action plan for controlling blood pressure.

Food preparation methods, drinking water source, and esophageal squamous cell carcinoma in the high-risk area of Golestan, Northeast Iran

Cooking practices and water sources have been associated with an increased risk of cancer, mainly through exposure to carcinogens such as heterocyclic amines, polycyclic aromatic hydrocarbons, and nitrates. Using data from the Golestan case-control study, carried out between 2003 and 2007 in a high-risk region for esophageal squamous cell carcinoma (ESCC), we sought to investigate the association between food preparation and drinking water sources and ESCC. Information on food preparation methods, sources of drinking water, and dietary habits was gathered from 300 cases and 571 controls matched individually for age, sex, and neighborhood using a structured questionnaire and a semiquantitative food frequency questionnaire. Multivariate conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for potential confounders and other known risk factors including socioeconomic status and smoking. More than 95% of the participants reported eating meat, mostly red meat. Red meat consumption above the 75th percentile increased the odds of ESCC by 2.82-fold (95% CI: 1.21-6.57). Fish intake was associated with a significant 68% decrease in ESCC odds (26%, 86%). Among meat eaters, ORs (95% CI) for frying meat (red or white) and fish were 3.34 (1.32-8.45) and 2.62 (1.24-5.5). Drinking unpiped water increased ESCC odds by 4.25 times (2.23-8.11). The OR for each 10-year increase in the duration of drinking unpiped water was 1.47 (1.22-1.78). Our results suggest roles for red meat intake, drinking water source, and food preparation methods in ESCC, even after adjusting for a large number of potential confounders.

A diversity of cancer incidence and mortality in West Asian populations

BACKGROUND

Western Asia comprises a large proportion of the world population with different ethnicities and religions inhabiting areas of diverse geographic features. The countries of this region have experienced rapid economic growth over the latter half of the 20th century, which continues to this day, resulting in major changes in lifestyle of the population.

OBJECTIVES

The aim of this study was to compare the incidence and mortality of cancer in West Asia using the estimates reported by the International Agency for Research on Cancer (IARC) in Globocan-2012.

METHODS

Countries with high-quality data or national data (based on the definition of the Globocan-2012) were included in the analysis. These included Bahrain, Iran, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, and Turkey. We also found high-quality cancer data from regional cancer registries in 3 Iranian and 3 Turkish provinces. Data on cancer incidence and mortality were collected and described in tables and graphs. Spearman's correlation test was used to assess the correlation between geographic coordinates and the incidence age-standardized rate (ASR; per 100,000 person-years) of cancers.

FINDINGS

Nine countries and 6 regional registries were included. Cancers of the lung (ASR, 33.3), prostate (24.9), bladder (19.1), stomach (16.5), and colorectal (15.9) were the most common malignancies in men. The most common cancers in women were those of the breast (35.4), colorectal (12.1), thyroid (10.3), stomach (9.2), and lung (6.7). The incidence rates of upper gastrointestinal and lung cancers were considerably higher in the northern part of this region, including Turkey and northern Iran compared with southern countries. High incidences of breast, colorectal, prostate, and bladder cancers were found in countries located in the northwest including Jordan, Lebanon, and Turkey.

CONCLUSIONS

The most common cancers differed by country. Consequently, cancer control programs must be tailored to the most common types of cancers in each country. Lack of high-quality data for some West Asian countries was the major limitation of this study. Therefore, as the first step of cancer control programs, it is recommended that well-structured population-based cancer registries be established in all of these countries.

Socioeconomic determinants of dietary patterns in low- and middle-income countries: a systematic review

BACKGROUND

In high-income countries, high socioeconomic status (SES) is generally associated with a healthier diet, but whether social differences in dietary intake are also present in low- and middle-income countries (LMICs) remains to be established.

OBJECTIVE

We performed a systematic review of studies that assessed the relation between SES and dietary intake in LMICs.

DESIGN

We carried out a systematic review of cohort and cross-sectional studies in adults in LMICs and published between 1996 and 2013. We assessed associations between markers of SES or urban and rural settings and dietary intake.

RESULTS

A total of 33 studies from 17 LMICs were included (5 low-income countries and 12 middle-income countries; 31 cross-sectional and 2 longitudinal studies). A majority of studies were conducted in Brazil (8), China (6), and Iran (4). High SES or living in urban areas was associated with higher intakes of calories; protein; total fat; cholesterol; polyunsaturated, saturated, and monounsaturated fatty acids; iron; and vitamins A and C and with lower intakes of carbohydrates and fiber. High SES was also associated with higher fruit and/or vegetable consumption, diet quality, and diversity. Although very few studies were performed in low-income countries, similar patterns were generally observed in both LMICs except for fruit intake, which was lower in urban than in rural areas in low-income countries.

CONCLUSIONS

In LMICs, high SES or living in urban areas is associated with overall healthier dietary patterns. However, it is also related to higher energy, cholesterol, and saturated fat intakes. Social inequalities in dietary intake should be considered in the prevention and control of noncommunicable diseases in LMICs.

Diet patterns and risk of squamous cell oesophageal carcinoma: a case-control study in Uruguay

BACKGROUND

Oesophageal cancer presents high incidence rates in the so-called Brazilian-Uruguayan belt.

MATERIALS AND METHODS

The present study included 1,170 participants (234 cases and 936 controls) which were analyzed by unconditional multiple logistic regression in order to examine risk of oesophageal squamous cell carcinoma (OESCC) associated with several food groups.

RESULTS

Boiled red meat (OR 2.59, 95%CI 1.69-3.97), lamb meat (OR 1.64, 95%CI 1.07-2.51), processed meat (OR 1.49, 95%CI 1.01-2.21), whole milk (OR 1.78, 1.19-1.68), fresh vegetables and fruits (OR 0.42, 95%CI 0.27-0.63), mate consumption (OR 2.04, 95%CI 1.32- 3.16), and black tea (OR 0.10, 95%CI 0.04-0.28) were significantly associated with risk of OESCC.

CONCLUSIONS

Hot beverages (mate) and hot foods (boiled meat) appear to be important determinants in the risk of OESCC, allowing the penetration of carcinogens in tobacco and alcohol into the oesophageal mucosa.

Reproductive factors and risk of esophageal squamous cell carcinoma in northern Iran: a case-control study in a high-risk area and literature review

Several epidemiologic studies have suggested an inverse association between female reproductive factors and the risk of esophageal squamous cell carcinoma (ESCC), but the evidence is not conclusive. We examined 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 the risk of ESCC in Golestan Province, a high-risk area in Iran. 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 the corresponding 95% confidence intervals (CIs). The average numbers of live births and miscarriages/stillbirths among the controls were 8.2 and 0.8, respectively. Women with six or more live births were at ~1/3 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 the risk of ESCC. The OR (95% CI) for at least three versus no miscarriages/stillbirths was 4.43 (2.11-9.33). The number of children in women was suggestive of an inverse association with ESCC, but this association was not statistically significant; in men, no association was observed. The findings of this study support a protective influence of female hormonal factors on the risk of ESCC. However, further epidemiological and mechanistic studies are required to prove a protective association.

Carotenoid intake and esophageal cancer risk: a meta-analysis

This meta-analysis was conducted to evaluate the association between intake of carotenoids and risk of esophageal cancer. A systematic search using PubMed, Cochrane Library, Web of Science, Scopus, CNKI, and CBM (updated to 6 May 2012) identified ten articles meeting the inclusion criteria with 1,958 cases of esophageal cancer and 4,529 controls. Higher intake of beta-carotene, alpha-carotene, lycopene, beta-cryptoxanthin, lutein, and zeaxanthin reduced esophageal cancer risk with pooled ORs of 0.58 (95% CI 0.44, 0.77), 0.81 (95% CI 0.70, 0.94), 0.75 (95% CI 0.64, 0.86), 0.80 (95% CI 0.66, 0.97), and 0.71 (95% CI 0.59, 0.87), respectively. In subgroup analyses, beta-carotene showed protective effects against esophageal adenocarcinoma in studies located in Europe and North America. Alpha-carotene, lycopene, and beta-cryptoxanthin showed protection against esophageal squamous cell cancer. This meta-analysis suggested that higher intake of carotenoids (beta-carotene, alpha- carotene, lycopene, beta-cryptoxanthin, lutein, and zeaxanthin) is associated with lower risk of esophageal cancer. Further research with large-sample studies need to be conducted to better clarify the potentially protective mechanisms of carotenoid associations risk of different types of esophageal cancer.

A U-shaped relationship between haematocrit and mortality in a large prospective cohort study

BACKGROUND

Only a limited number of studies have investigated the correlation between haematocrit (HCT) and mortality in the general population, and few of those studies have had data on a wide range of low and high levels of HCT. We investigated the association between baseline HCT and mortality in a prospective cohort study of 49,983 adult subjects in Iran with a broad spectrum of HCT values.

METHODS

Data on socio-demographic and life-style factors, past medical history, and levels of HCT were collected at enrollment. During a mean follow-up of 5 years (follow-up success rate ~99%), 2262 deaths were reported. Cox proportional hazards regression models were used to estimate hazard ratios and corresponding 95% confidence intervals.

RESULTS

There was a U-shaped relationship between categories of HCT and mortality in both sexes: both low and high levels of HCT were associated with increased overall mortality and mortality from cardiovascular disease. The U-shaped relationship persisted after several sensitivity analyses were done, including analyses restricted to non-smokers and non-users of opium; analyses excluding deaths from accidents and other external causes as well as deaths of persons with self-reported ischemic heart disease at the baseline interview for the study; and analyses excluding the first 2 years of follow-up. Self-reported past medical history and lack of data about lipids and other cellular blood components were the major limitations of the study.

CONCLUSIONS

Low and high levels of HCT are associated with increased mortality in the general population. The findings in the present study can be of particular importance for low- and middle-income countries in which a substantial proportion of the population lives with suboptimal levels of HCT.

Higher glycemic index and glycemic load diet is associated with increased risk of esophageal squamous cell carcinoma: a case-control study

Several studies have indicated the association between intake of foods high in dietary glycemic index (GI) and glycemic load (GL) with an increased risk of digestive tract cancers. We hypothesized that GI and GL may be associated with risk of esophageal squamous cell carcinoma (ESCC) in a high-risk population in Iran. In total, we interviewed 47 cases with incident of ESCC and 96 frequency-matched hospital controls, then calculated the average dietary GI and GL via a validated food frequency questionnaire. Dietary GL was calculated as a function of GI, carbohydrate content, and frequency of intake of certain foods. Dietary GI and GL levels were significantly higher among the ESCC cases compared with the controls (P < .05). After adjustment for potential confounders, those in the highest tertile of dietary GI had 2.95 times higher risk of ESCC compared with those in the lowest (95% confidence interval, 1.68-3.35; P for trend = .002). In addition, being in the highest tertile of dietary GL was positively associated with an ESCC risk (odds ratio, 3.49; 95% confidence interval, 2.98-4.41; P for trend = .001). Findings of the present study indicate that diets with high GI and GL might have potentially unfavorable effects on ESCC risk and suggest a possible role for excess circulating insulin and related insulin-like growth factor 1 in esophageal cancer development.

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.

Viral load of HPV 16/18 in esophageal squamous cell carcinoma in three ethnic groups living in Xinjiang Autonomous Region, China

To investigate the viral load of human papillomavirus (HPV) in esophageal squamous cell carcinoma (ESCC) patients from three ethnic groups in Xinjiang. Using Gp5+/Gp6+ consensus primers, the prevalence of HPV DNA was examined in 253 paraffin-embedded ESCC samples. The presence and viral load of HPV 16 and HPV 18 were detected in Kazakhs, Uygurs and Hans using type-specific primers by quantitative real-time PCR (qRT-PCR). Among the 253 ESCC samples, 52 cases were positive for HPV DNA, all the 52 positive cases displayed HPV 16 infection, and six of the 52 cases were co-infected by HPV 16 and 18. HPV 16-positive rate and viral load were higher in lesions, and was inversely correlated with differentiation grades. However, there was no statistic significance among different differentiation grades. Also, there were no significant difference between detection rates of HPV types, viral load and age, gender, ethnic group, and lymph node metastasis. HPV 16 and HPV 18 genotypes could simultaneously be detected in ESCC specimens in three main ethnic groups in Xinjiang. The viral load of HPV 16 is higher in the ESCC lesions, and is inversely correlated with the differentiation grades. These observations reinforce the suggestion that HPV infection may involved in ESCC carcinogenesis; however, high prevalence or viral load of HPV infection does not seem to be related with high incidence of ESCC in Kazakhs, which may be the one element among the multiple risk factors contributing to ESCC.

HPV infection in Brazilian patients with esophageal squamous cell carcinoma: interpopulational differences, lack of correlation with surrogate markers and clinicopathological parameters

The role of HPV in esophageal squamous cell carcinoma (ESCCs) is controversial. Therefore, we determined, through different methodologies, the prevalence of HPV in 264 ESCC samples from Brazil, and correlated it with the presence of surrogate markers and clinicopathological characteristics. HPV is present in 13% of ESCC, and with a 3-fold variation between high and medium incidence areas. Most HPV positive tumors were infected with HPV16, but this was not associated with p16 expression, TP53 mutation status, patient age, amount of tobacco or alcohol consumption, or overall survival. We conclude that HPV infection may not have a role in ESCC.

Dietary patterns differ between urban and rural older, long-term survivors of breast, prostate, and colorectal cancer and are associated with body mass index

BACKGROUND

Older adult cancer survivors are at greater risk of cancer recurrence and other comorbidities that can be prevented through improved diet and weight management. The tertiary prevention needs of rural-dwelling survivors can be even greater, yet little is known about rural and urban differences in lifestyle factors among this high-risk population.

OBJECTIVES

To compare dietary patterns of urban and rural cancer survivors and to examine associations of dietary patterns with body mass index (BMI).

DESIGN

A secondary analysis was performed of baseline data from the Reach Out to Enhance Wellness (RENEW) trial, a diet and exercise intervention among overweight, long-term (≥5 years), older survivors of colorectal, breast, and prostate cancer. Survivors in the present analysis (n=729) underwent two 45- to 60-minute telephone surveys, which included two 24-hour dietary recalls. Principal components analysis and multivariable general linear models were used to derive dietary patterns and to evaluate associations between dietary patterns and BMI, respectively.

RESULTS

Principal components analysis identified three primary dietary patterns among rural dwellers (high sweets and starches, high reduced-fat dairy, cereal, nuts, and fruits, and mixed) and three among urban dwellers (high fruits and vegetables, high meat and refined grains, and high sugar-sweetened beverages). Among rural survivors, greater adherence to the high reduced-fat dairy, cereal, nuts, and fruits pattern was positively associated with lower BMI (P trend <0.05), whereas higher scores on the mixed pattern was associated with greater BMI (P trend <0.05). Greater adherence to the high fruits and vegetables pattern among urban survivors was inversely associated with BMI (P trend <0.05).

CONCLUSIONS

Urban and rural differences in dietary intake behavior should be considered in designing public health interventions among the increasing population of older cancer survivors. In addition, targeting overall dietary patterns might be one approach to help reduce the burden of obesity among this population.

A pilot survey for Fusarium mycotoxin biomarkers in women from Golestan, northern Iran

Fusarium mycotoxins are frequent contaminants of cereals in many world regions, and are suggested risk factors for various acute and chronic human diseases. To date a lack of exposure tools has restricted epidemiological studies of the potential health effects. Recently established exposure biomarkers for deoxynivalenol (DON) and fumonisins are now available and here a pilot biomarker survey of 110 women (aged 39 to 72 years) from Golestan, northern Iran was conducted on samples collected at one time point during August-September 2007. Urinary DON and DON-glucuronide combined were detected frequently (79/110, 72%), mean 1.3 ng DON/ml urine, range not detected (nd)-6.5 ng/ml; mean creatinine adjusted levels were 1.5 ng DON/mg creatinine, range nd-7.1 ng/mg). Neither urinary de-epoxy DON (DOM-1) and DOM-1 glucuronide combined, nor urinary fumonisin B1 were detected. This study is the first reported biomarker based exposure assessment of DON and fumonisins in this region. Overall DON exposure at this time point appears modest compared to other world regions where data are available.

Meat consumption, cooking methods, mutagens, and risk of squamous cell carcinoma of the esophagus: a case-control study in Uruguay

The role of meat in squamous cell carcinoma of the esophagus (ESCC) has been considered conflictive. For this reason, we decided to conduct a case-control study on meat consumption and ESCC. Data included 234 newly diagnosed and microscopically examined ESCC and 2,020 controls with conditions not related to tobacco smoking nor alcohol drinking and without changes in their diets. We studied total meat, red meat, beef, lamb, processed meat, poultry, fish, total white meat, liver, fried meat, barbecued meat, boiled meat, heterocyclic amines, nitrosodimethylamine, and benzo[a]pyrene in relation with the risk of ESCC. Red meat, lamb, and boiled meat were directly associated with the risk of ESCC, whereas total white meat, poultry, fish, and liver were mainly protective against this malignancy.

Esophagitis may not be a Major Precursor Lesion for Esophageal Squamous Cell Carcinoma in a High Incidence Area in North-Eastern Iran

BACKGROUND Esophageal squamous cell carcinoma (ESCC) is usually detected in advanced stages resulting in a very poor prognosis. Early diagnosis needs identification of clinically relevant precancerous lesions which could become the target of screening and early treatment. Our aim was to check whether esophagitis could serve as a relevant histological precursor of ESCC in Northern Iran. METHODS During 2001-2005, all adult patients who were referred to Atrak clinic for upper gastrointestinal endoscopy and biopsy were enrolled. Atrak clinic is a major center for upper gastrointestinal cancer research in eastern Golestan. All subjects had been complaining of upper GI symptoms and were under further investigation to rule out cancer. Biopsies from the endoscopically normal mid-esophagus and also just above the esophago-gastric junction were obtained in all subjects whose esophagus appeared normal during endoscopy and from endoscopically normal appearing mucosa at the proximal vicinity of any detected mass. Microscopic examinations for the verification of the presence or absence of esophagitis was performed by independant histological examination of the samples by two pathologists. All the discrepant diagnoses were resolved in joint diagnostic sessions. RESULTS During the study period 836 patients were enrolled including 419 non cancer patients (endoscopy clinic controls), 387 cancer patients, and 30 subjects with clinical diagnosis of malignancy referred for histological reconfirmation of diagnosis by repeated biopsy. Mild or marked mid-esophagitis was diagnosed in 39 (9.3%), 47 (12.5%) and 12 (40%) of endoscopy clinic controls, cancer patients and those who were suspicious for upper gastrointestinal malignancies. CONCLUSION Our observation does not show evidence for esophagitis to be a predisposing factor for ESCC in Gonbad region In North Eastern Iran.

Specific intronic p53 mutation in esophageal squamous cell carcinoma in Southern Thailand

AIM

To investigate p53 mutations in esophageal cancer in a high-risk population, and correlate them with smoking, alcohol consumption and betel chewing.

METHODS

One hundred and sixty-five tumor samples of esophageal squamous cell carcinoma (ESCC) obtained from a university hospital in Songkhla province, Southern Thailand were investigated for p53 mutations in exons 5-8, using polymerase chain reaction-single strand conformation polymorphism analysis, followed by direct sequencing. A polymerase chain reaction-restriction fragment length polymorphism (RFLP) assay was additionally used to confirm possible germline mutation in intron 6. A history of risk habits was obtained by interviews. The association between risk habits and mutation frequency was evaluated using the χ(2) test.

RESULTS

The studied specimens were from 139 male and 26 female patients with ESCC, treated at Songklanagarind Hospital. Most of the patients were smokers (86.7%) and alcohol consumers (72.73%), and 38.3% were betel chewers. Forty-three mutations of the p53 gene were detected in 25.5% (42/165) of tumor samples. Mutations were most commonly found in exon 5 (25.6%) and exon 8 (25.6%). Mutations in the hot-spot codon 248 were found in four cases (9.3% of all mutations). G:C→C:G (30.23%), G:C→A:T (27.90%) and G:C→T:A (16.28%) were the prevalent spectra of mutations. Unexpectedly, among 10 intronic mutations, eight cases harbored a similar mutation: G→C substitution in intron 6 (nucleotide 12759, GenBank NC_000017). These were additionally confirmed by the RFLP technique. Similar mutations were also detected in their matched blood samples using RFLP and direct sequencing, which suggested germline mutations. There was no significant correlation between risk habits and p53 mutation frequency.

CONCLUSION

A proportion of Thai ESCC patients harbored specific intronic p53 mutations, which might be germline mutations. Further studies are needed to explore this novel finding.

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.

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.