Application of Bayesian Multilevel Space-Time Models to Study Relative Risk of Esophageal Cancer in Iran 2005-2007 at a County Level

Scientometric Analysis of Articles on Spatial Epidemiology of Cancer in Iran: A Systematic Review

Background

Geographic information system (GIS) plays an important role in identifying areas with a high incidence of cancer. In the present study, based on a systematic review of studies by Iranian researchers, we performed a scientometric analysis of the published articles on the spatial epidemiology of cancer. In addition, the geographical distribution of certain types of cancer in Iran is presented.

Methods

A literature search was conducted using electronic databases such as PubMed and NLM Gateway, Institute for Scientific Information, Scopus, Google Scholar, and Cochrane Library for relevant articles published from 2000 to 2021. The search was performed using a combination of medical subject heading terms and keywords. A narrative synthesis was performed, and descriptive data were expressed as frequency and percentage.

Results

Of the 200 identified articles, 31 studies published in 15 different journals were included in this systematic review. Results showed a wide variation in high-risk breast cancer clusters. However, a similar incidence of gastrointestinal cancers has been reported, and high-risk clusters were identified in the north and the northwest of Iran. Skin cancer and acute lymphoblastic leukemia were more prevalent in the central provinces.

Conclusion

The current volume of studies on the spatial epidemiology of cancer in Iran, with a CiteScore quartile of Q1, is inadequate to guide health policymakers. The geographical distribution of many prevalent types of cancer has not been assessed by Iranian researchers. Furthermore, the classification of high- and low-risk geographical clusters of cancers was not completely homogeneous.

Epidemiology and trends of gastrointestinal cancer in Iran (2004-2008)

Aim

Gastrointestinal (GI) cancer is among the most common cancers in Iran. The main purpose of this study was to evaluate changes in the time trends of stomach, colon and rectum, and esophageal cancer during the past decade in Iran.

Materials and Methods

In this cross-sectional study, the study population was all cases of GI cancers diagnosed in Iran between 2004 and 2008. Cancer incidence data for the years 2004-2008 were obtained from the cancer registry system of the Ministry of Health. All incidence rates were directly age standardized to the world standard population. Age-Satndardized incidence rate (ASR)per 10⁵ persons was calculated using direct standardization and the world standard population. The crude rate was calculated in this study. Data were analyzed using SPSS (version 17) and Microsoft Office Excel 2007.

Results

During the 2004-2008 period, the ASR and crude rates of GI cancers, including esophagus, stomach, colon and rectum, among males were 5.05, 15.02, and 8.29 and 4.01, 11.81, and 6.4, respectively, and among females were 6.52, 7.055, and 7.75 and 4.40, 4.85, and 5.49, respectively. The most common cancers in women were colon and rectum, and stomach cancer had the highest incidence in males. In this study, most cases of stomach cancer were adenocarcinoma adenocarcinoma (Nos) in both women and men. The most common type of colorectal cancer was adenocarcinoma, which was greater in men than women. The most common type of esophageal cancer was squamous cell carcinoma in both sexes. The north and northwestern regions of Iran have the highest risk of GI cancer.

Conclusion

According to this study, a significant increase was observed in the incidence of cancers in the north and western regions of Iran. Hence, screening and early detection programs are highly recommended in these high-risk areas.

Design and evaluation of a theory-based intervention of knowledge and perceptions to improve self-care amongst relatives of esophageal cancer patients: A randomised controlled trial study protocol

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Emphasis on training programs to increase self-care behaviors.

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The EPPM can successfully predict behavioral intention and self-care behaviors.

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The EPPM can consider as a framework for developing educational interventions.

Background

Esophageal cancer, as one of the most unknown cancers, is largely preventable through lifestyle modifications. In this study, a theory-based intervention will be designed and evaluated on the knowledge and perceptions of relatives of patients with cancer to improve their self-care.

Methods

This research will be carried out in two phases in Golestan province, located in north of Iran. A researcher-made questionnaire will be designed based on the extended parallel process model using a detailed literature review and the panel of experts' opinions. This questionnaire will aim to investigate the levels of knowledge, perception, and practice of respondents regarding esophageal cancer. Later, a comprehensive program will be designed over esophageal cancer self-care based on the information collected from the questionnaire, the information obtained from detailed literature review, and the experts' opinions. The second phase of the study will include implementation of an educational intervention with pretest–posttest design using the intervention and control groups to measure the effectiveness of this educational program on the knowledge, perception, and practice of the patients' relatives.

Discussion

The findings will provide valuable evidences regarding the efficacy of the educational intervention and will help the participants to improve their self-care behaviours. Consequently, policy-makers and planners can use the results to set appropriate policies.

Time Series Analysis of Monthly Suicide Rates in West of Iran, 2006-2013

INTRODUCTION

Iran's western provinces have higher suicide rate compared to the other provinces of the country. Although suicide rates fluctuate over time, suitable statistical models can describe their underlying stochastic dynamics.

METHODS

This study was conducted to explore the fluctuations of the monthly suicide rates in the most populated western province of Iran using exponential smoothing state space model to compute the forecasts. For this reason, the monthly frequencies of completed suicides were converted to rates per 100,000 and a state-space approach was identified and fitted to the monthly suicide rates. Diagnostic checks were performed to determine the adequacy of the fitted model.

RESULTS

A significant seasonal variation was detected in completed suicide with a peak in August. Diagnostic checks and the time series graph of the observed monthly suicide rates against predicted values from the fitted model showed that in the study period (from March 2006 to September 2013), the observed and predicted values were in agreement. Thus, the model was used to obtain the short-term forecasts of the monthly suicide rates.

CONCLUSIONS

In this study, we had no significant trend but seasonal variations in the suicide rates that were identified. However, additional data from other parts of the country with longer duration are needed to visualize the reliable trend of suicide and identify seasonality of suicide across the country.

Trends and Risk Factors of Gastric Cancer in Iran (2005-2010)

Background:

Gastric cancer (GC) is the first and the third prevalent cancer among males and females in Iran, respectively. The aim of this study was mainly to identify high-risk areas of GC by assessing the spatial and temporal pattern of incidence, and second, to explore some risk factors of GC in ecological setting.

Methods:

In this cross-sectional ecological study we used Bayesian hierarchical space-time model to measure the relative risk and temporal trends of GC in Iran from 2005 to 2010 based on available data. Data analysis was done by the use of integrated nested Laplace approximation Bayesian approach in R software.

Results:

Overall trend of GC was significantly decreasing during the study period. Ardabil, Khorasan Razavi, West Azarbaijan, Zanjan, and Mazandaran provinces had the highest risk of incidence. Overweight and smoking were directly and significantly associated with GC risk.

Conclusions:

During the study period, GC has decreased in Iran. Nevertheless, GC risk was generally high in Northern and Northwestern provinces of Iran. Different health policies according to GC risk and trend are required for each province. Improvements in screening and education programs and conducting further epidemiological studies could help to reduce the incidence of GC in high risk provinces.

Bivariate Spatio-Temporal Shared Component Modeling: Mapping of Relative Death Risk due to Colorectal and Stomach Cancers in Iran Provinces

BACKGROUND

Gastrointestinal cancers make for nearly half fatal cancers with colorectal and stomach cancers' being listed among the ten most common in Iran. This research aims to determine the spatial pattern and temporal trend of death risk due to colorectal and stomach cancers among provinces of Iran and estimate the effect of shared and specific components as surrogates of risk factors for the aforementioned cancers on changes of death due to the cancers over time and place.

METHODS

In this ecological study, the data regarding death causes in colorectal and stomach cancers during 2006-2011 were obtained from the death registration system of the Iranian Ministry of Health. The estimation of relative risk (RR) of death due to the target cancers was performed applying Bayesian spatiotemporal shared component (SC) model in OpenBUGS software.

RESULTS

North-Western provinces ranked first regarding stomach cancer RR of death (RR >1.75). Furthermore, some North-Western and central provinces had the highest RR of death due to colorectal cancer (RR >1.5). The SC surrogating the risk factor shared between both cancers had the most effect in Northern, North-Western and western provinces, and the least effect in Southern and South-Eastern ones.

CONCLUSIONS

North and North-West of Iran found to be the high-risk area for death due to both stomach and colorectal cancers and South-East and South provinces shown to have the lowest RR. The obtained results can be illuminating to health resource allocation to the health policymakers.

Mapping of Stomach, Colorectal, and Bladder Cancers in Iran, 2004-2009: Applying Bayesian Polytomous Logit Model

BACKGROUND

According to the last report of Iran cancer registry, stomach, colorectal, and bladder cancers are the most prevalent cancers. The present study focused on separating the latent risk surface into shared and disease-specific components.

METHODS

In this study, data consisting of stomach, colorectal, and bladder cancers in 30 provinces of Iran during 2004-2009 are considered. These data are analyzed by polytomous logit model. The incidence of stomach cancer acts as the reference category (the surrogate for smoking). Then, the log odds are decomposed into shared and specific structured spatial and unstructured spatial components. These latent components help to detect spatial patterns of shared and disease-specific risk factors.

RESULTS

Central, Southern, Eastern, and Southwestern provinces are supposed as high-risk regions for shared risk factor for colorectal and bladder cancers. This shared risk factor is slightly associated more with bladder than with colorectal cancer. Northern, northwestern, and central regions and also three borderline provinces in southwestern are high-risk regions for colorectal cancer. Central, eastern, southern, and western strip of the country except Ilam are found as the high-risk regions of bladder cancer.

CONCLUSIONS

After considering known shared risk factor of the three cancers, it turns out that colorectal and bladder cancers have unknown shared risk factor. The significant difference in their lifestyle and eating habits could be an assumption of the risk factor.

Joint Spatio-Temporal Shared Component Model with an Application in Iran Cancer Data

Background: Among the proposals for joint disease mapping, the shared component model has become more popular. Another advance to strengthen inference of disease data is the extension of purely spatial models to include time aspect. We aim to combine the idea of multivariate shared components with spatio-temporal modelling in a joint disease mapping model and apply it for incidence rates of seven prevalent cancers in Iran which together account for approximately 50% of all cancers. Methods: In the proposed model, each component is shared by different subsets of diseases, spatial and temporal trends are considered for each component, and the relative weight of these trends for each component for each relevant disease can be estimated. Results: For esophagus and stomach cancers the Northern provinces was the area of high risk. For colorectal cancer Gilan, Semnan, Fars, Isfahan, Yazd and East-Azerbaijan were the highest risk provinces. For bladder and lung cancer, the northwest were the highest risk area. For prostate and breast cancers, Isfahan, Yazd, Fars, Tehran, Semnan, Mazandaran and Khorasane-Razavi were the highest risk part. The smoking component, shared by esophagus, stomach, bladder and lung, had more effect in Gilan, Mazandaran, Chaharmahal and Bakhtiari, Kohgilouyeh and Boyerahmad, Ardebil and Tehran provinces, in turn. For overweight and obesity component, shared by esophagus, colorectal, prostate and breast cancers the largest effect was found for Tehran, Khorasane-Razavi, Semnan, Yazd, Isfahan, Fars, Mazandaran and Gilan, in turn. For low physical activity component, shared by colorectal and breast cancers North-Khorasan, Ardebil, Golestan, Ilam, Khorasane-Razavi and South-Khorasan had the largest effects, in turn. The smoking component is significantly more important for stomach than for esophagus, bladder and lung. The overweight and obesity had significantly more effect for colorectal than of esophagus cancer. Conclusions: The presented model is a valuable model to model geographical and temporal variation among diseases and has some interesting potential features and benefits over other joint models.