Breast cancer incidence trends in Golestan, Iran: An age-period-cohort analysis by ethnic region, 2004-2018.

BACKGROUND: We aimed to examine the effects of age, diagnosis year (calendar period) and birth year (cohort) on the incidence trends of breast cancer among Golestan women, Northeast Iran, 2004-2018. METHODS: Incidence data were obtained by residential status (urban/rural) and ethnic region (Turkmens/non-Turkmens). We calculated age-standardized incidence rates (ASRs) per 100,000 person-years. The estimated annual percentage change (EAPC) were calculated, and age-period-cohort (APC) models fitted to assess non-linear effects of period and cohort as incidence rate ratios (IRRs). RESULTS: The total number of female breast cancer cases in Golestan, 2004-2018, were 3853, with an overall ASR of 31.3. We found higher rates in urban population (40.5) and non-Turkmens region (38.5) compared to rural area (20.8) and Turkmens region (20.2), respectively. There were increasing trends in incidence rates overall (EAPC= 4.4; 95%CI: 2.2, 6.7), with greater changes in rural areas (EAPC=5.1), particularly among non-Turkmens (EAPC=5.8). The results of the APC analysis indicate the presence of significant non-linear cohort effects with increasing IRRs across successive birth cohorts (IRR=0.1 and IRR= 2.6 for the oldest and the youngest birth cohorts vs. the reference birth cohort, respectively). CONCLUSION: We found increasing trends in breast cancer incidence among Golestan women over the study period, with disparities in patterns and trends by residence area and ethnic region. The observed cohort effects suggest an increasing prevalence of key risk factors for breast cancer in this Iranian population. Further investigations are warranted to clarify the relationships between determinants such as reproductive factors and ethnicity in the region.

Incidence and Temporal Variations of Bone and Soft Tissue Cancers in the Golestan Province, Northern Iran, 2004-2016.

BACKGROUND: This study was conducted to evaluate the epidemiological features of bone and soft cancers in the Golestan province, Northern Iran from 2004 to 2016. METHODS: This is a descriptive cross-sectional study. All patients with primary bone and soft tissue cancers between 2004 and 2016 were included. Data were obtained from Golestan population-based cancer registry (GPCR). We calculated age-standardized incidence rates (ASRs) and reported the rates per 100000 person-year. Estimated annual percent change (EAPC) was also calculated to assess temporal trends in incidence rates of these cancers. RESULTS: The ASRs of bone cancers and soft tissue cancers were 1.33 and 1.43 per 100000 person-year, respectively. This study also showed that the ASR of bone cancer was higher in men (1.51) than women (1.15). The ASR of soft tissue cancers in the urban population (1.58) was higher than rural (1.27), and was lower in women (1.37) than men (1.49). Two peaks were seen in the incidence of bone cancer. The first peak was in the age group of 10 to 20 years and the second was in patients over 60. We did not find significant temporal trends in the incidence of bone (EAPC=-1.14; P>0.05) and soft tissue cancers (EAPC=-2.73; P>0.05) during the study period. CONCLUSION: Epidemiological features of bone and soft tissue cancers including gender, age and place of residence should be considered by health policy makers in designing cancer control programs.

Esophageal and gastric cancer incidence trends in Golestan, Iran: An age-period-cohort analysis 2004 to 2018.

Golestan province in the northeast of Iran is part of the Asian esophageal cancer belt and is known as a high-risk area for esophageal (EC) and gastric cancers (GC). Data on incident cases of EC and GC during 2004 to 2018 were obtained from the Golestan Population-based Cancer Registry (GPCR). The age-standardized incidence rates (ASRs) were calculated and presented per 100 000 person-years. The estimated annual percentage change (EAPC) with 95% confidence interval (95% CI) were calculated. We also fitted age-period-cohort (APC) models to assess nonlinear period and cohort effects as incidence rate ratios (IRRs). Overall, 3004 new cases of EC (ASR = 15.7) and 3553 cases of GC (ASR = 18.3) were registered in the GPCR. We found significant decreasing trends in incidence rates of EC (EAPC = -5.0; 95% CI: -7.8 to -2.2) and less marked nonsignificant trends for GC (EAPC = -1.4; 95% CI: -4.0 to 1.4) during 2004 to 2018. There was a strong cohort effect for EC with a consistent decrease in the IRR across successive birth cohorts, starting with the oldest birth cohort (1924; IRR = 1.9 vs the reference birth cohort of 1947) through to the most recent cohort born in 1988 (IRR = 0.1). The marked declines in EC incidence rates in Golestan relate to generational changes in its underlying risk factors. Despite favorable trends, this population remains at high risk of both EC and GC. Further studies are warranted to measure the impact of the major risk factors on incidence with a view to designing effective preventative programs.

Primary Biliary Tract Cancers in Golestan, Iran: 13-Year Experience of Golestan Population-Based Cancer Registry.

BACKGROUND: Epidemiological research on the high-risk population might be helpful in early detection and prevention of biliary tract malignancies. This study assesses the prevalence of biliary tract cancer (BTC) in the Golestan province, northeastern Iran, between 2004 and 2016. METHODS: The current study used information from the Golestan Population-based Cancer Registry (GPCR) to access the epidemiology of BTC across a 13-year period while taking into account temporal and geographic differences. The number of cases, crude rates, age-standardized incidence rates (ASRs) per 100,000 person-years, average annual percent change (AAPC), age-specific incidence rates, and 95% confidence intervals (CI) were reported for each year with respect to gender and place of residence. RESULTS: Totally, 224 instances of BTC overall (54% of whom were females) were reported throughout the research period. The ASR of BTC was 1.7 (95% CI: 1.4‒2) for females and 1.4 (95% CI: 1.1‒1.6) for men, respectively. Males exhibited a growing time trend in incidence (AAPC: 7.18; CI: 0.06‒14.81; P-value:0.048), whereas females had a decreasing trend (AAPC: 0.82; CI: -5.94‒4.57; P-value: 0.740). Both sexes saw an increase in age-specific incidence rates starting at the age of 45; however, males experienced a significant increase in incidence in the age group of 75 to 79 while the female rates grew steadily. CONCLUSION: The focus for cancer control in this region may be given to demographic groups with a combination of risk factors, including male gender, older age, and urban residence.

Population-based cancer survival in the Golestan province in the northeastern part of Iran 2007-2012.

OBJECTIVE: We studied 5-year relative survival (RS) for 14 leading cancer sites in the population-based cancer registry (PBCR) of Golestan province in the northeastern part of Iran. METHODOLOGY: We followed patients diagnosed in 2007-2012 through data linkage with different databases, including the national causes of death registry and vital statistics office. We also followed the remaining patients through active contact. We used relative survival (RS) analysis to estimate 5-year age-standardized net survival for each cancer site. Multiple Imputation (MI) method was performed to obtain vital status for loss to follow-up (LTFU) cases. RESULTS: We followed 6910 cancer patients from Golestan PBCR. However, 2162 patients were loss to follow-up. We found a higher RS in women (29.5%, 95% CI, 27.5, 31.7) than men (21.0%, 95% CI, 19.5, 22.5). The highest RS was observed for breast cancer in women (RS=49.8%, 95% CI, 42.2, 56.9) and colon cancer in men (RS=37.9%, 95% CI, 31.2, 44.6). Pancreatic cancer had the lowest RS both in men (RS= 8.7%, 95% CI, 4.1, 13.5) and women (RS= 7.9%, 95% CI, 5.0, 10.8) CONCLUSION: Although the 5-year cancer survival rates were relatively low in the Golestan province, there were distinct variations by cancer site. Further studies are required to evaluate the survival trends in Golestan province over time and compare them with the rates in the neighboring provinces and other countries in the region.

Temporal and Geographical Trends of Incidence of Thyroid Cancer in Golestan, Iran, 2004-2013.

BACKGROUND: Thyroid cancer is the most common type of endocrine cancer. We aimed to determine the incidence rates of thyroid cancer across a 10-year period (2004-2013) in Golestan, Iran. METHODS: We obtained the thyroid cancer data from Golestan Population-Based Cancer Registry (GPCR). Age-standardized incidence rates (ASR) were calculated and reported per 100000 person-years. The Joinpoint software was used to assess time trends, and average annual percent changes (AAPCs) and their corresponding 95% confidence intervals (CIs) were reported. RESULTS: Of 326 registered patients, 83 (25.5%) were men and 243 (74.5%) were women. The mean age was 51.3 and 42.6 years for males and females, respectively. Overall, the ASR of thyroid cancer was 2.2 per 100000 person-year (AAPC = 2.76; 95% CI: -3.68 to 9.64). The test of co-incidence showed a statistically significant difference in the incidence of thyroid cancer between men (1.3) and women (3.2) (P < 0.001). According to our results, the ASR of thyroid cancer in western parts of Golestan is higher, including Gorgan and Aliabad cities. CONCLUSION: Increasing trends in incidence rates of thyroid cancer were found in the Golestan province during the study period, especially in women. We found significantly higher rates of thyroid cancer in women. Geographical diversities were seen in incidence rates of thyroid cancer in the Golestan province. Our results may be helpful for designing further researches to investigate the epidemiological aspects of thyroid cancer in the Golestan province.

10-Year Trends in Dietary Intakes in the High- and Low-Risk Areas for Esophageal Cancer: A Population-Based Ecological Study in Northern Iran.

BACKGROUND We assessed dietary intakes in the high- and low-risk areas for esophageal cancer (EC) in Golestan province, Northern Iran. METHODS Considering the EC rates, Golestan province was divided into high- and low-risk regions. Data on households' food consumption were obtained from the Statistical Center of Iran. We used multivariable logistic regression to assess the relationships between consumption of main food and EC risk. Adjusted odds ratios (aOR) were calculated. Joint point program was used for time trend analysis and average annual percent changes (AAPC) were reported. RESULTS Overall, 11910 households were recruited during 2006-2015. 4710 (39.5%) households were enrolled from the high-risk region. There were significant positive relationships between high consumption of sweets (aOR = 1.62; 95% CI: 1.24-2.10), oil/fat (aOR = 1.36; 95% CI: 1.04-1.79), and red meat (aOR = 1.33; 95% CI: 1.07-1.65) with EC risk. We found significant negative relationships between high consumption of dairy products (aOR = 0.62; 95% CI: 0.46-0.82), vegetables (aOR = 0.66; 95% CI: 0.50-0.87) and fruit (aOR = 0.72; 95% CI: 0.55-0.95) with the risk of EC. Time trend analysis showed a significant increasing trend in the proportions of households with low consumption of vegetables (AAPC = 4.71, p = 0.01) and dairy products (AAPC = 5.26, p = 0.02) in the low-risk region for EC. CONCLUSION Dietary intakes may be important etiological factors for EC in Northern Iran. Further studies are warranted to assess the role of dietary factors in this high-risk population.

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.

Recent cancer incidence trends and short-term predictions in Golestan, Iran 2004-2025.

BACKGROUND: We examine recent trends in the major cancers occurring in the Golestan province, a high-risk region for upper gastrointestinal cancers in Northern Iran, and provide short-term cancer predictions of the future cancer burden. METHODS: New cancer cases diagnosed in Golestan 2004-2016 were obtained from the Golestan population-based cancer registry (GPCR) database, and age-standardized rates by cancer site, year and sex calculated per 100,000 person-years. Using IARC's DepPred package we fitted time-linear age-period models to the available GPCR data to predict the cancer incidence burden in the year 2025. We calculated the contribution of demographic changes versus changes in risk to the overall changes in incidence from 2016 to 2025. RESULTS: The number of new cancer cases (excluding non-melanoma skin cancers) in 2025 is predicted to increase by 61.3% from 2678 cases in 2016 to 4319 cases. While a 17.6% reduction in the number of esophageal cancer cases is predicted by 2025, the number of new cases for each of the remaining major cancers is predicted to increase over the next decade, including cancers of the stomach (a 36.1% increase from 2016 to 2025), colorectum (56.2%), lung (67.8%), female breast (93.2%), prostate (101.8%) and leukemia (96.1%). The changes in the population structure and risk contributed 37.8% and 23.5% respectively, to the overall increase in incidence. CONCLUSION: Other than for the major upper gastrointestinal cancer types, the incidence rates of common cancers observed in the province are on the rise, reinforcing the need for continuous surveillance, as well as the design and implementation of effective cancer control programs.

Descriptive Epidemiology of Lymphoma in Northern Iran: Results from the Golestan Registry 2004-2013.

BACKGROUND: There is currently little known about the epidemiology of lymphomas in Iran. The aim of this paper is to describe the geographic and time variations in incidence rates of lymphomas in the Golestan province between 2004 and 2013. METHODS: The Golestan Population-based Cancer Registry (GPCR) routinely registers primary cancer patients from all sources (e.g. pathology centers, hospitals, etc.) throughout the Golestan province. We obtained data on newly-diagnosed lymphomas in Golestan during 2004-2013 from the GPCR dataset. Crude rates and age standardized incidence (ASR) rates (per 100000) of lymphomas were estimated, joinpoint regression was used to quantify incidence trends and average annual percent changes (AAPCs) were calculated. RESULTS: In total, 898 new cases of lymphoma were registered in the GPCR during 2004-2013. The ASR of Hodgkin lymphoma (HL) was 1.5 and 1.1 in males and females, respectively, while corresponding non-Hodgkin lymphoma (NHL) rates were greater, at 6.5 and 3.4 in males and females, respectively. Our results indicated a significant difference in the trends of HL between males (AAPC = -3.2) and females (AAPC = 3.6, P value = 0.001). The incidence rates of lymphoma were considerably higher in the urban population (ASR = 7.3) compared to those residing in rural areas (ASR = 5.3, P value = 0.054). We also found higher incidence rates for both HL and NHL in the western parts of the Golestan province. CONCLUSION: The incidence rates of lymphoma in the Golestan province are relatively high and vary geographically, with a higher incidence observed in the western area. Such differences may reflect unknown lifestyle and environmental determinants linked to ethnic susceptibility differing between the two areas.

Increasing trends of lung cancer in Golestan province, Northern Iran (2004-2016).

INTRODUCTION: We aimed to present the time trends and geographical distribution of lung cancer in Golestan province, a high-risk area for pulmonary tuberculosis (TB) in Northern Iran (2004-2016). METHODS: Data on incident primary lung cancers were obtained from the Golestan population-based cancer registry. The data were analyzed by CanReg-5 software to calculate the age-standardized incidence rates (ASRs). We used Joinpoint software for time trend analysis. Average annual percent changes were calculated. The contribution of population aging, population growth and risk to the overall changes in incidence of lung cancer were determined using partitioning analysis. RESULTS: Overall, 1829 cases of lung cancer were registered by the GPCR during 2004-2016, of which 1274 (69.7%, ASR in 2016 = 21.3) were men and 555 (30.3%, ASR in 2016 = 11.4) were women. The results of Joinpoint regression suggested a significant increasing trend in incidence of lung cancer in Golestan province during 2004 and 2016 (AAPC = 3.74; p-value = 0.01) with more prominent increasing in rural population (AAPC = 4.93; p-value<0.01). The number of new cases of lung cancer increased by 131.6% (from 98 in 2004 to 227 in 2016), of which 34.1%, 22.3% and 75.3% were due to population size, population aging and risk, respectively. Hot points of lung cancer were found in western parts of the Golestan. CONCLUSION: With high incidence rates and increasing trends of lung cancer, further studies are warranted to clarify the role of TB and other risk factors on its burden in this population.

Assessing the Correlation of Fecal Calprotectin and the Clinical Disease Activity Index in Patients With Ulcerative Colitis.

It has been shown that fecal calprotectin can be used to evaluate mucosal inflammation better than using clinical indices and serum markers. The aim of this study was to assess the use of fecal calprotectin for evaluating the disease activity in 2 groups of patients with ulcerative colitis and a control group. The study population consisted of 30 patients with active-phase ulcerative colitis, 30 remission-phase patients, and 30 healthy control patients. After obtaining informed consent, we took blood and fecal samples. Fecal calprotectin was assessed by the enzyme-linked immunosorbent assay method; levels of more than 200 µg/g were considered abnormal. The Simple Clinical Colitis Activity Index was used to evaluate disease activity. A one-way analysis of variance test and a Pearson correlation test were used to analyze the results. The means ±SD of the disease activity index were 4 ± 2.8, 6 ± 1.9, and 2.7 ± 2.5 in patients with active-phase and remission-phase ulcerative colitis, respectively (p < .001). Fecal calprotectin (µg/g) values (mean ±SD) for active-phase patients, remission-phase patients, and the control group patients were significantly different: 711.7 ± 228, 517 ± 328.2, and 304 ± 297.5, respectively. There was a significant correlation between fecal calprotectin and the disease activity index values (r = .41; p = .004). Fecal calprotectin could be a useful tool in assessing the bowel disease activity in patients with ulcerative colitis.

Building cancer registries in a lower resource setting: The 10-year experience of Golestan, Northern Iran.

INTRODUCTION: The Golestan population-based cancer registry (GPCR) was established in Golestan province, Northern Iran, within the Asian belt with predominance of upper-gastrointestinal cancers. We aimed to present the experiences of the registry in a resource-limited setting over the 10 years since its inception (2004-2013). METHODS: The GPCR was established as a research project to enable sustainable funding. A clear plan was developed for use of the GPCR data. New primary cancers were registered based on international standards, indices of data quality were routinely assessed and age-standardized incidence rates (ASR) per 100,000 person-years calculated using IARC's CanReg-5 software. RESULTS: Overall, 19807 new cancer cases were registered during the study period, an average of 1981 cases per annum, with overall ASR of 175.0 and 142.4 in males and females, respectively. The GPCR data suggested gastrointestinal and breast cancers as the most common malignancies in Golestan province. We observed increasing incidence rates of breast and colorectal cancers but declining trends of esophageal cancer. Overall, indices of data quality were within acceptable ranges. CONCLUSIONS: The GPCR data have been included in IARC's Cancer Incidence in Five Continents series, were used in 21 research projects, and published as 30 research papers. The key ingredients for the successful establishment and maintenance of the GPCR included sustainable sources of funding, a clear action plan for the use of data as well as stakeholder cooperation across all areas of the registration. The GPCR may be considered as a model for planning population-based cancer registries in lesser-resourced settings.

Hesa-A Effects on Cell Cycle Signaling in Esophageal Carcinoma Cell Line.

BACKGROUND Hesa-A is a natural compound with anticancer properties. The exact mechanism of its action in esophageal cancer is not clear, yet. The aim of this study was to evaluate the cell toxicity effect of Hesa-A on the esophageal carcinoma cell lines, KYSE-30, and cell cycle genes expression. METHODS In this study, we tested cell toxicity with MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay and flow cytometry to evaluatet he cell cycle arrest. Real time polymerase chain reaction was used to assess the expression of P53, P16, P21, cyclin D1, and cyclin B1 genes. RESULTS Our results showed that Hesa-A is effective in the expression of cell cycling check point proteins. Hesa-A induced an arrest in G2 phase of esophageal cell cycle. The levels of P53 (>13 times), P21 (>21 times), P16, cyclin B1, and cyclin D1 genes were increased 48 hours after Hesa-A treatment. CONCLUSION P21 and P16 expression were the potential mechanisms for G2 arrest of KYSE-30 esophageal cancer cell line by Hesa-A.

Quantitative Determination of Aflatoxin by High Performance Liquid Chromatography in Wheat Silos in Golestan Province, North of Iran.

BACKGROUND: Aflatoxins are the most common mycotoxins that contaminate crops. They are produced by fungi such as Aspergillus flavus and Aspergillus parasiticus. Wheat (Tricitumaestivum) is one of the most important staple foods used in Iran, and the environmental conditions in the north of Iran are favorable to fungal growth. This study was designed in order to determine the aflatoxin concentration in wheat samples from silos in Golestan Province north of Iran. METHODS: Samples were collected from three silos of Golestan province. First, aflatoxins were isolated using immunoaffinity chromatography. Then the aflatoxin concentrations were determined by High performance liquid chromatography (HPLC) method and fluorescence detector. RESULTS: Ten out of 34 samples (29.4% of samples) were contaminated by aflatoxins.No concentration was found above permitted aflatoxin levels in Iran (15 ng/g). In one sample (2.9%), aflatoxin B1 was seen over the permissible limits in Iran. The highest level found in samples for total aflatoxin, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2 were 7.08 ng/g, 6.91 ng/g, 0.29 ng/g, 1.37 ng/g and 0.23 ng/g, respectively. No correlation was found between humidity levels in wheat samples contained aflatoxin and wheat samples without aflatoxin. CONCLUSION: Despite the total aflatoxins determined in samples were below the permissible limits in Iran, the 29% aflatoxin contamination rate can negatively affect health factors and it should not be neglected. So, it is predictable that if the storage duration of samples increases, the aflatoxin contamination levels will increase.

Temporal variations of dietary habits in a high-risk area for upper gastrointestinal cancers: a population-based study from northern Iran.

BACKGROUND: Nutrition transition is a global health problem, especially in developing countries. It is known as an important factor for development of different types of health conditions including cancers. OBJECTIVES: We aimed to assess the pattern of nutrition transition in a high-risk area for upper gastrointestinal cancers in Northern Iran during the last decade. MATERIALS AND METHODS: This cross-sectional study was conducted on households of Golestan province, Iran. Data on household food consumption between 2001 and 2010 were obtained from the Statistical Center of Iran. The proportions of households with medium/high consumption of main foods were calculated for each year. Joint point software was used for assessing trends. Annual percent changes (APCs) and 95%CIs were calculated. RESULTS: In total, 12,060 households were recruited. The APCs (95%CI) of the proportion of households medium/high consumption of cereals, vegetables, legumes, fish, dairy products and meats were -3.1 (-4.1 to -2.2), -2.9 (-3.8 to -2.1), -2.3 (-3.2 to -1.4), -2.8 (-3.3 to -2.4), -1.9 (-3.0 to -0.9) and 2.7 (1.2 to 4.3), respectively. CONCLUSIONS: We found significant increase in meat consumption among our population between 2001 and 2010. Our results also suggested significant decreasing trend in consumption of so-called healthy foods including, plant foods, fish, and dairy products. Regarding its correlation with health conditions including cancers, nutrition transition should be considered as a priority in health policy making in our region as well as other high-risk populations. It is recommended to conduct community level interventions to increase consumption of plant foods, fish, and dairy products.

Aflatoxin contamination of wheat flour and the risk of esophageal cancer in a high risk area in Iran.

BACKGROUND: Golestan province in northeastern Iran has been known as a high-risk area for esophageal cancer (EC). This study was conducted to assess aflatoxin (AF) contamination of wheat flour (WF) samples in high and low EC-risk areas of Golestan province. METHODS: Four WF samples were collected randomly from each of 25 active silos throughout the province in 2009. The levels of AFs were measured using the High-performance liquid chromatography method. Using the data of EC rates obtained from Golestan population-based cancer registry, the province was divided into high and low risk areas for EC. Student t-test and multivariate regression analysis were used to compare the levels of aflatoxins as well as the condition of silos between the two areas. RESULTS: One hundred WF samples were collected. The mean levels of total aflatoxin and aflatoxin B1 was 1.99 and 0.53 ng g(-1), respectively. The levels of total AF (p = 0.03), AFG2 (p = 0.02) and AFB1 (p = 0.003) were significantly higher in samples obtained from high risk area. Multivariate regression analysis showed that humidity of silo was the most important source of difference between silos of the two areas (p = 0.04). CONCLUSION: We found a positive relationship between AF level of WF samples and the risk of EC. So, AF contamination may be a possible risk factor for EC in our region. We also found that humidity of silos was the most important determinant of AF contamination of WF. Intensive control of silos conditions including humidity and temperature are needed especially in high EC-risk areas.