Iranian Journal of Epidemiology
Year:2010 | Volume:6 | Issue:3|Papers Count:12

Background and objective: Disease or mortality mapping are statistical methods aimed at providing precise estimates of rates across geographical maps. The aim of this research is to improve the precision of relative risk (RR) estimates of infant mortality (IM) for different rural areas, using empirical and full Bayesian methods.Methods: Infant mortality data were extracted from the vital horoscope (Zij-Hayati) for years 2001 and 2006 across rural areas of Iran. Maximum Likelihood, Empirical Bayes with Poisson-Gamma model and full Bayesian models were used. Mont Carlo Markov Chain method was used for latter models. Deviance information criterion (DIC) was computed to check the models fittings. R, WinBUGS and Arc GIS software were employed.Results: Based on the full Bayesian method, the highest RR of infant mortality was 1.73 (95% CI: 1.58-1.88) in year 2001 and 1.62 (95% CI: 1.50-1.75) in 2006 which belonged to Sistan-va-Blouchestan area in comparison to the whole country. In 2001, the rural areas of Birjand (1.45), Kordistan (1.23) and Khorasan (1.21) and in 2006, Birjand (1.42), Zanjan (1.39), Kordistan (1.36), Ardebil (1.32), Zabol (1.28), West Azerbaijan (1.18) and finally Golestan (1.14) had significant RR of IM (all p<0.05). The lowest RR of infant mortality for year 2001 belonged to rural areas of Tehran University (0.56) and for year 2006 to former Iran University (0.52).Conclusion: To estimate the mortality map parameters, the full Bayesian method is preferred compared to empirical Bayes and maximum likelihood.

Background & Objective: Refractive errors (myopia, hyperopia and astigmatism) could lead to an impaired quality of life affect a large proportion of the population worldwide, irrespective of age, sex and ethnic group. Such refractive errors can be easily diagnosed, measured and corrected with spectacles or other refractive corrections to attain normal vision. Since there is paucity of information in school children in Iran we aimed to investigate the distribution pattern of refractive status and prevalence of refractive errors in school-age children in Shiraz.Methods: A random sampling strategy in geographically defined clusters was used to identify children aged 6-15 years in Shiraz between 2008-2209. We carried out a school survey and actual eye examinations, including visual acuity measurements, stereopsis examination, anterior segment and eyeball movements, fundus examinations, and cycloplegic retinoscopy with 1% cyclopentolate.Results: Of 3065 selected individuals, 2683 were participated in the study (response rate 86.6%). According to cycloplegic refraction, 4.85% (95% (CI), 3.52 to 6.16) of the primary and middle school students were myopic and 4.64% (95% CI, 3.52 to 6.19) were hyperopic. For high school students, these rates were 22.19 and 11.4% respectively. Myopia and hyperopia were shown to be correlated with age. Prevalence of anisometropia, amblyopia and strabismus were 2.51%, 2.31 (95% CI 1.51-3.11) and 1.83% (95% CI 1.15-2.50).Conclusion: Compared to other published reports, the rate of myopia in the school children of Shiraz seems relatively high.

Background & Objectives: The Cox proportional-hazards regression and other parametric models model have achieved widespread use in the analysis of time-to-event data with censoring and covariates. However employing Bayesian method has not been widely used or discussed. The aim of this study was to evaluate the prognostic factors in using Bayesian interval censoring analysis.Methods: This cohort study was based on 178 patients with gastric cancer from January 2003 to December 2007 admitted to Taleghani teaching hospital in Tehran. Known prognostic risk factors were entered into the analysis using Bayesian Weibull and Exponential models. The term DIC was employed to find best model.Results: The results were showed survival rate depended on age of diagnosis and tumor size. Those patients who had early diagnosis and/or had smaller tumor size were in lower risk of death.Conclusion: The age of diagnosis and tumor size of patients are important prognostic factors related to survival of patients with gastric cancer. Based on DIC, Bayesian analysis of the Weilbull model performed better than the Exponential model. As a result, if this cancer has been diagnosed early, the relative risk of death would reduce.

Background & Objective: Using parametric models is common approach in survival analysis. In the recent years, artificial neural network (ANN) models have increasingly used in survival prediction. The aim of this study was to predict of survival rate of patients with gastric cancer by using a parametric regression and ANN models and compare these methods.Methods: We used the data of 436 gastric cancer patients from a cancer registry in Tehran in 2002-2007. All patients had a confirmed diagnosis. Data were randomly divided into two groups: training and testing (or validation) set. For analysis of data we used a parametric model (exponential, Weibull, normal, lognormal, logistic and log-logistic models) and a three layer ANN model. In order to compare of the prediction of two models, we used the area under receiver operating characteristic (AUROC) curve, classification table and concordance index.Results: The prediction accuracy of the ANN and the parametric (Weibull) models were 79.45% and 73.97% respectively. The AUROC for the ANN and the Weibull models were 0.815 and 0.748 respectively.Conclusions: The ANN had better predictions than the Weibull model. Thus it is suggested to use of the ANN model survival prediction in field of cancer.

Background & objectives: However outbreaks of cholera are not very common in central area of Iran; in 2008 district health authority reported a cluster of diarrhea cases. We investigated this cluster to identify the etiological agent, source of transmission and propose control measures.Methods: We defined a case of diarrhea as occurrence of > or=3 loose/watery stools a day among the residents of Karaj. Fifty four (54) cases were identified in health care centers and 106 healthy individuals as control. We conducted a gender- and age-matched case-control study to identify risk factors.Results: Vibrio cholerae El Tor O1 Inaba was isolated from all cases rectal swabs. During cholera epidemic outbreak in 2007, 54 cases of stool-culture were vibrio cholera, serotype Inaba positive. Using industrial-ice and fruits and vegetables were significantly associated with the illness (OR 4.4 and 3.3 respectively).Conclusions: This outbreak was due to a contaminated industrial-ice and contaminated vegetables and fruits and V. cholera 01 Inaba was possibly the causative organism. Therefore more prevention program and observation methods should be considered.

Background & Objectives: Cholera is always being considered as a public health threat in poor and developing countries. However outbreaks of cholera are not very common in central area of Iran; in 2008 district health authority reported a cluster of diarrhea cases. We investigated this cluster to identify the etiological agent, source of transmission and propose control measures.Methods: We analyzed the data of total of 1219 patients with colorectal cancer who registered between 1 January 2002 and 1 October 2007. Data were analyzed using univariate and multivariate Accelerated Failure Time (AFT) parametric survival model with frailty, utilizing STATA statistical software.Results: In the univariate analysis for age at diagnosis, gender, marital status, race and education level, the survival of patients with colon cancer were approximately between half to one fourth and for BMI, alcohol history, Inflammatory Bowel Disease (IBD), familial history of cancer and the pathologic stage of tumor, the survival of patients with colon cancer were significantly (between 0.12 to 0.56 times) shorter than those patients with rectal cancer. In the multivariate analysis, for age at diagnosis (45-65 years), there was significant difference between colon and rectum cancer. But for BMI, alcohol history, IBD and pathologic stage there were not significant differences. The adjusted survival and 1, 2, 3, 4 and 5 year survival of patients with rectal cancer were better than those with colon cancer.Conclusions: Site-specific evaluation of colon and rectum could give a better perspective of factors affecting these cancers. It may help to design of clinical trials, better diagnosis of diseases and optimal administration of specific treatments.

Background & objectives: Oral disease is a significant burden to all countries of the world. Since there is little know about this in Iran we decided to identify of oral mucosal disease in patients referred to Oral Medicine Center affiliated to Tabriz Dental School.Methods: A consecutive sample of admitted patients to OMC between April and June 2007 were included in this study. We employed a standard questionnaire in order to.Results: Eight hundred two patients were completed the requested questionnaire. Seventy percent was female. The mean age of the study sample was 32.68 (SD=12.25) years. Approximately 70% of subjects had oral lesion, 19.2% had normal mucosa and 21.60% of patients had oral mucosal lesions that need to follow and control. The most common lesions were ankiloglossia (29.7%) then fissural tongue (25.7%) and coated tongue (23.7%).Conclusions: Many patients attending the center were unaware of oral lesions in their soft oral tissue which needed to follow up. This emphasizes that examination of soft oral tissue should be considered by health policy makers in oral health agenda at national level.

Background & objectives: Personnel who regularly practice invasive procedures such as blood sample collection are particularly at risk to percutaneous injuries. Needle stick injuries present the single greatest risk to medical personnel. This study was undertaken to analyze the problem of needle sticks injuries among health care workers at teaching hospitals in Urmia in 2008 year.Methods: This cross-sectional study was conducted among 400 personals of Urmia teaching hospitals. A structured questionnaire was used to interview the study participants at their work place. Participants were asked to recall needle stick injuries in the preceding 12 months. Factors such as work experience, type of procedure, action taken following injury etc. were also studied. The samples were selected by using simple random sampling in every hospital. The data were analyzed according to aims, by using Descriptive and analytical method.Results: Around 25% (107.400) of the Health care workers had experienced a needle stick injury in the last six-months. Needle sticks injuries in females and male was 28% and 24% respectively. Most of the injuries created by needle (47.3%) and anjiocat needle (19.9%).Conclusions: The results of this study show that the prevalence rates of needle stick injuries are a major risk in hospitals personnel. Therefore there is a need at the hospital level to have a uniform needle stick injuries policy covering safe work practices, safe disposal of sharps, procedures in event of needle stick injury, training including pre-employment training monitoring and evaluation of needle stick injuries and procedures for reporting needle stick injuries.