Iranian Journal of Epidemiology
Year:2007 | Volume:3 | Issue:1-2|Papers Count:12

Background & Objectives: Tobacco smoking is known to cause a huge burden of disease throughout the world: smoking is responsible for 4 million deaths per year. This study is performed in order to fill the existing gaps in information regarding current trends for lifestyle and tobacco-related disease in Iran.Methods: This was a cross-sectional study performed with the help of a questionnaire and using a multi-stage cluster sampling method. The final sample size, after the screening of the data, was 84706 out of 89457 records.Results: From a total of 84706 people in this study, 49.7% were men, 52% were uneducated and 64.8% cane from urban areas; 79.9% did not smoke, 15.3% smoked actively, 2.1% were non-active smokers and 2.7% were ex-smokers. The prevalence of smoking was higher in people aged 35 to 64 years (P<0.001). Quitting rates increased with age, especially in women (P<0.001). Smoking was more prevalent in men (P<0.001) and in rural areas (P<0.001). The average number of cigarettes smoked per day was 14.69. Smoking prevalence was lower among adults with higher levels of education compared to those with lower education levels (P<0.001).Conclusions: This nationwide survey provides a baseline for future longitudinal studies of smoking in Iran. There is a need for effective smoking prevention and cessation programs with a focus on the young population.

Background & Objectives: Early detection can improve the outcome of visual impairment in children, and one method for early detection could be screening of pre-school children with visual acuity tests. The aim of this study was to determine the validity of these tests when they are used on children entering grade school.Methods: For this cross-sectional study we drew 39 random clusters, comprising a total of 5721 school children. We then used 2158 student files to extract data on tests of vision performed by school health officers and compared these data with data generated by optometrists.  Measurement of uncorrected visual acuity was done with the E Chart by both teachers and optometrists.Results: The sensitivity and specificity of teacher-administered tests were 25.0% and 96.6%, yielding positive and negative predictive values of 13.4% and 98.4%, respectively. Sensitivity and specificity rates did not show any significant difference between male and female populations (P=0.356, P=0.258), but the difference between specificity in urban and rural areas was significant (P<0.001).Conclusions: Screening tests for visual impairment did not attain the desired level of sensitivity or specificity for case detection in school children. More accurate procedures are required to minimize the number of false negative results.

Background & Objectives: Cancer has been traditionally regarded as a fatal disease; it is a major public health problem in many countries throughout the world. In recent years, cancer morbidity and mortality has increased in our country and notably stomach cancer now ranks second or third among all cancers types with regard to morbidity.Methods: Our study included all gastric cancer patients registered in the cancer registry of Fars province. The patients' survival status was followed using phone calls and death records from hospitals, other medical centers, and the city's cemetery. Data analysis involved the use of the nonparametric Kaplan-Meier and Cox proportional hazards models and was performed with the software package SPSS V.13.Results: Of the 442 patients with gastric cancer, 303 cases (68.6 percents) were male, and the mean age of patients was 58.41 years (SD=14.46). In univariate analysis with the KM method, a statistically significant association was found between survival rates and the following factors: age at diagnosis (P<0.001), tumor grade (P=0.009), presence of metastases (P<0.001), and type of the initial treatment (P=<0.001). Factors without a significant relationship with the survival rate included sex, ethnicity, weight, BMI, tobacco use, history of cancer in close or distant relatives, place of residence, number of children, marital status, occupation, and income. In Cox regression, only age at diagnosis, tumor grade, and the presence of metastases showed a significant association with survival rates.Conclusions: Our results imply that early detection of cancer at a lower age and in lower tumor grades could be important for increasing the patients' life expectancy.

Background & Objectives: Although Cox regression is commonly used to detect relationships between patient survival and demographic/clinical variables, there are situations where parametric models can yield more accurate results. The objective of this study was to compare two survival regression methods, namely Cox regression and parametric models, in patients with gastric carcinoma registered at Taleghani Hospital, Tehran.Methods: Using data from 746 patients who had received care at Taleghani Hospital from February 2003 through January 2007, we compared survival rates between different patient groups with both parametric methods and Cox regression models. The former group included Weibull, exponential and log-normal regression; we used the Akaike Information Criterion (AIC) and standardized parameter estimates to compare the efficiency of various models. All the analyses were performed with the SAS software and the level of significance was set at P<0.05.Results: The results showed a significantly higher chance of survival in the following subgroups: those with age at diagnosis <35 years, lower tumor size and those without metastases (P<0.05). According to AIC, Cox and exponentials model are similar in multivariate analysis but in univariate analysis parametric models are more efficient than Cox, except in the case of tumor size. Log-normal appears to be the best model.Conclusions: Cox and exponential models have similar performance in multivariate analysis. However, it seems that there is no single model that performs substantially better than others in univariate analysis. The data strongly supported the log-normal regression among parametric models; it can give more precise results and can be used as an alternative for Cox in survival analysis of patients with gastric cancer.

Background & Objectives: To determine the risk factors for acute diarrhea disease in children.Methods: This study involved 220 cases and 220 controls in Dr. Sheykh Hospital, a specialzed pediatric hospital in Mashhad. Cases were children seen in the emergency department with loose watery feces, diagnosed as acute diarrhea by the physician. The controls were selected from the same setting as the cases and included children with traumas, burns, acute respiratory complaints and other diseases.Results: In univariate logistic regression, variables having a significant relationship with acute diarrhea disease included formula feeding in the first 6 months of life, antibiotic therapy over the preceding 15 days, mother's employment, mother's acquaintance with oral rehydration solutions, place of residence, and disruption in the water supply in the week before illness. We performed multiple logistic regression to examine the role of these variables as independent risk factors for acute diarrhea. Use of formulas before 6 months of age (OR=3.21, 95%CI: 1.77-5.79), and type of residence (OR=1.83, 95%CI: 1.24-2.71), and mother's employment (OR=2.48, 95%CI: 1.2-5.06) were the factors that remained in the multiple logistic model and had a significant relationship with the disease.Conclusions: This study identified some environmental risk factors for acute diarrhea disease. High-risk groups and mothers of children under 5 years of age should be aware of these risk factors in order to prevent disease in their children. Prevention of acute diarrhea in children can significantly reduce the current burden on the health system.

Background & Objectives: There is little doubt about the importance of accurate statistics and reliable information in the promoting community health and optimizing health care. Therefore, the existence of a correct, accurate and up to date database is an absolute necessity. Accurate identification of the cause in death certificates can make an invaluable contribution to the development of such a database. The purpose of this research was to assess the current defects and shortcomings in death certificates and to evaluate the degree of agreement between the diagnoses recorded in hospital files those figuring on death certificates.Methods: This was an analytic cross–sectional study. In this survey of 659 medical records of dead patients in Loghman Hospital, during 2005, 290 medical records were selected using a systematic sampling method. The selection of these records were based on record numbers in the archives and involved the extraction of the following data: the physician's field of specialty, the patient's identity, code for the main diagnosis, the code for the external cause on the admission form, and the code for the cause of death on the death (as defined in ICD-10) was recorded. The agreement between primary and final diagnoses and also the agreement between final diagnosis and the cause of death were assessed in relation with the physician's specialty; using Fisher's Exact Test. Overall agreement between different diagnoses was measured using the kappa statistic.Results: The degree of agreement between primary and final diagnosis was very good (k=0.83) and agreement between final diagnosis and cause of death was excellent (k=0.95). Fisher's exact test showed that agreement between primary and final diagnoses and between final diagnoses and cause of death doesn't depend on the physician's specialty (in both cases p>0.01). In 62% percent of the cases death had occurred without interference from an external cause. Among the 38% in which there was an external cause, 21% involved poisoning with suicidal intent, 12% were due to accidental poisoning, 4% were motor accidents, and 1% were due to other reasons.Conclusions: There was a high degree of agreement between different diagnoses in some specialties, while didn't observe such agreement in other specialties. Since accurate diagnosis helps in identifying the cause of death and death information is an important indicator of health at community level, we recommend that physicians pay greater attention to accurate recording of the cause of death. This will make it possible to draw meaningful comparisons between the causes of death in Iran and those in other countries.

Background & Objectives: The summer of 2005 witnessed an outbreak of cholera in Iran due to V. cholera, Inaba serotype. During the outbreak, there were 16 registered cases in Markazi Province. The aim of this study was to determine the risk factors for cholera outbreak in this part of the country.Methods: This was a case-control study in which cases were matched to controls on age and sex. All of the reported cases were compared with controls from the same neighborhood, with 2 controls selected for each case. We used paired odds ratios and conditional logistic regression to show the effect of each putative risk factor, and p values of < 0.05 were considered as statistically significant.Results: Multivariate results from 16 cases and 32 controls showed significant associations between the cholera outbreak and the following set of factors: eating raw vegetable (OR=9, 95%CI: 2.25-35.98), proper warming of refrigerated food (OR=0.12, 95%CI: 0.015-1.022), inadequate washing of fruits and vegetables (OR=4.29, 95% CI: 0.88-21.06) , and eating non-pasteurized ice creams (OR=4.96, 95%CI: 0.99-24.83).Conclusions: Although the number of reported cases was small in Markazi Province, the results show that education in personal hygiene is important in the prevention of a cholera outbreak.

Background & Objectives: Recent evidence suggests that long-term exposure to air pollution contributes to progression of atherosclerosis and the risk of cardiac morbidity and mortality; short-term exposure may also lead to thrombosis and acute ischemic events. To evaluate the relation between the levels of major air pollutants (CO and PM10) and hospital admission for acute coronary syndrome (ACS) in Tehran, we performed a case-crossover design and checked whether individual characteristics act as effect modifiers.Methods: We selected 250 Tehran residents who had been hospitalized with an acute coronary syndrome from 4th of April to 10th of June, 2007. The following individual data were gathered: sex, age, date of hospitalization, and coexisting illnesses (hypertension, diabetes). Daily air pollution data were taken from the Air Quality Control Center. Temperature, humidity, stress, physical activity and weekend days were treated as confounding variables, and a conditional logistic regression model was used for statistical analysis.Results: We found a positive association between ACS and average 24-hour CO levels. The OR for each unit increase of the average 24-hour CO was 1.18 (95%CI: 1.03-1.34). The relation between ACS and 24-hour average PM10 did not reach statistical significance (OR for average 24-hour PM10 was 1.005, 95%CI: 0.99-1.01). The association between ACS and 24-hour average CO tended to be stronger in women (OR=1.68 for each unit increase, 95%CI: 1.25-2.26). The relation between 24-hour average PM10 and ACS did not change across the layers of the effect modifiers.Conclusions: The results suggest that an increase in average 24-hour CO levels will augment the risk of ACS, and the effect is stronger in females. On the other hand, we were unable to document an association between ACS and average 24-hour PM10 levels.

Background & Objectives: Drug abuse and addiction is one of the four major crises in the world. The first step in combating any disease or social problem is proper organization. The aim of this case-control study was comparing the distribution of blood groups between healthy blood donors and clients of drug rehabilitation clinics in the city of Bam.Methods: In this case-control study, cases were 249 drug users attending the city's rehabilitation clinic. Controls included 360 healthy blood donors at the headquarters of the Blood Transfusion Organization in Bam. We extracted and analyzed data on demographic characteristics, blood group and RH, using the software package SPSS.Results: This study showed that the AB blood type is more common in drug addicts than in healthy blood donors.Conclusions: Many studies have reported that an association between ABO blood groups/ RH and various health outcomes such as infections and non-infectious diseases as well as mental and social problems. Our study showed that there is a significant relationship between drug addiction, AB blood type, and negative RH. It therefore seems that genes play a role in the tendency towards addiction. This investigation may be valuable in the sense that it may prompt further research in fields such as genetic, immunology and other related disciplines.

Background and Objectives: There are conflicting data on the effects of different types of fat on aortic atherosclerosis. This study used Wister rats to compare the atherogenic effects of a standard diet with a diet containing fish oil and another diet containing mixed oils (typical of the current consumption pattern in Iran).Methods: Thirty female Wistar rats were randomly assigned to three diet groups: a standard diet (containing soy bean-oil as the only dietary fat), a diet containing fish oil and another diet which contained mixed oils and was designed on the basis of the current fat consumption pattern in Iran (butter, hydrogenated vegetable oil and sunflower oil). Mothers in each group were fed the same diet during pregnancy and lactation; the litters were also weaned onto the same diet. Aortic samples were taken from the offspring at the time of weaning and puberty. Data were analyzed using SPSS software; Kruskal-Wallis test was applied for comparison among groups.Results: Rats that were fed soy bean oil showed less extensive fatty streaks and intimal thickening of aorta on weaning and at puberty. Rats fed fish oil and mixed oils showed more atherosclerosis lesions compared to those receiving soy bean oil.Conclusions: It seems that diets with an omega-3 to omega-6 ratio of 0.6 can enhance aortic atherosclerosis. Diets with an Iranian fat consumption pattern also increase aortic atherosclerotic lesions because they contain substantial amounts of saturated fat.