Background: Colorectal cancers, including colon, rectum and anus, are relatively prevalent in Iran. Use of opium and its derivatives is also considerably prevalent in some areas in Iran. Objectives: The aim of this study was to assess the association between use of opium and its derivatives, and incidence of lower gastrointestinal (LGI) cancers. Methods: This study was a matched case-control study in Shiraz (south of Iran). Cases were the new colorectal cancers from cancer registry center of Shiraz University of Medical Sciences and controls were selected from healthy volunteers of cases' neighbors matched for age and gender (2 controls per 1 case). Data related to consumption of opium and its derivatives, smoking, alcohol use and diet status were collected through a structured questionnaire. The conditional logistic regression models were used to assess all associations. Results: 160 cases and 320 controls participated in the present study with non-response rate less than 9 %. Opium use was associated with increased risk of colorectal cancer (adjusted OR = 4.4; 95% CI: 2.2 -8.8). Also, a dose-response association was observed between cumulative consumption of opium and the colorectal cancer incidence (OR = 3.8; 95% CI: 1.5 -9.1), and (OR = 4.6; 95% CI: 1.7 -12.0) for low and high use, respectively. Also, the significant dose-response association was observed for low (OR = 3.4; 95% CI: 1.2 -9.2) and high (OR = 7.7; 95% CI: 1.5 -38.6) opium use with presence of colon cancer.
Conclusions:The results of this study showed that opium use can be an important risk factor for colorectal cancer in Iran.
Quantile regression is an efficient method for predicting and estimating the relationship between explanatory variables and percentile points of the response distribution, particularly for extreme percentiles of the distribution. To study the relationship between urbanization and cancer morbidity, we here applied quantile regression. This cross-sectional study was conducted for 9 cancers in 345 cities in 2007 in Iran. Data were obtained from the Ministry of Health and Medical Education and the relationship between urbanization and cancer morbidity was investigated using quantile regression and least square regression. Fitting models were compared using AIC criteria. R (3.0.1) software and the Quantreg package were used for statistical analysis. With the quantile regression model all percentiles for breast, colorectal, prostate, lung and pancreas cancers demonstrated increasing incidence rate with urbanization. The maximum increase for breast cancer was in the 90th percentile (β=0.13, p-value<0.001), for colorectal cancer was in the 75th percentile (β=0.048 ,p-value<0.001), for prostate cancer the 95th percentile (β=0.55, p-value<0.001), for lung cancer was in 95th percentile (β=0.52, p-value=0.006), for pancreas cancer was in 10th percentile (β=0.011, p-value<0.001). For gastric, esophageal and skin cancers, with increasing urbanization, the incidence rate was decreased. The maximum decrease for gastric cancer was in the 90th percentile(β=0.003, p-value<0.001), for esophageal cancer the 95th (β=0.04, p-value=0.4) and for skin cancer also the 95th (β=0.145, p-value=0.071). The AIC showed that for upper percentiles, the fitting of quantile regression was better than least square regression. According to the results of this study, the significant impact of urbanization on cancer morbidity requirs more effort and planning by policymakers and administrators in order to reduce risk factors such as pollution in urban areas and ensure proper nutrition recommendations are made.
Introduction: Cancer is one of the main causes for mortality and morbidity in the world. Identifying epidemiology and the trend of esophageal cancer may be highly effective in related planning. The present study has been carried out with the aim of exploring the morbidity and trend of esophageal cancer in Iran.
Methods:The present study is a type of repeated analysis of the existing data. The population of this study consisted of the cancer registry data during the years (2003)(2004)(2005)(2006)(2007)(2008)(2009)) in Iran. The direct incidence rate was standard according to the World Health Organization (WHO) population. The incidence trend of this disease in this country was drawn by the means of the STATA software and the significance of the morbidity trend diagram was also derived via WINPEPI software.
Results:The results indicated the increasing trend of esophageal cancer up to 2008 while this trend has been dropping during the years 2008-9. The 31914 cases of esophageal cancer which have been recorded throughout the country out of which this rate has been increased from 2759 cases in 2003 to 6210 cases in 2009 so this rate signifies 2 times in morbidity and the recording of cases. During this 7-year career, the maximum incidence rate was related to the Ardabil province with 19.03 per 100'000 cases in 2009 while the minimum incidence rate was related to Chahar Mahal and Bakhtiari and also Booshehr provinces with 0.48 and 0.42% per 1000 cases in 2003, respectively. Conclusion: The incidence rate of esophageal cancer in Iran is increasing, particularly in the northern and northwestern regions of the country. It is recommended to employ screening programs and premature diagnosis in the regions and among high risk populations.
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