Iranian Journal of Epidemiology
Year:2010 | Volume:6 | Issue:2|Papers Count:11

Background and objective: The nested case-control study has become popular as an efficient alternative to the full-cohort design. This study compares the results of a nested case-control analysis approach with the full cohort analysis.Methods: A cohort of 276 subjects (new cases from a TB registry) was used for this study. Cox Regression model was used for the full cohort analysis. In order to do the nested case-control analysis, for each death, three random controls were selected from those who did not suffer from the outcome at the time of the outcome took place. Case control data was analyzed by the conditional logistic regression model.Results: Results from both cohort and nested case-control analyses show that treatment group is the only variable that affects on the outcome. Gender, place of residence, and age has no effect on the outcome. For binary exposure variables with trivial effects (e.g. Gender and place of residence), the relative efficiency of nested case-control study design is approximately 75%.Conclusion: Results of this study show that nested case-control study is not only an easy and cost-effective method for data analysis but also is as robust as cohort analysis in rate ratio and its variance estimation.

Background & Objective: Physical activity is important for the health of all individuals; however, the determinants of physical activity behavior for elderly remain unexplored in Iran. The purpose of this investigation was to explore a range of factors that influence participation in physical activity for a group pf elderly people in Tehran in 2008.Methods: This was a population-based study. Structured interviews with a valid questionnaire were employed for this survey. It was carried out on four hundred members of Healthy Association in Tehran. Multistage sampling was used.Results: The mean age of participants was 64.07±4.49. The prevalence of a sedentary lifestyle among elderly fifty-three (53%) estimated. The prevalence across the stages was as follows: 30.25% in pre contemplation, 12.75%in contemplation, 27.25% in preparation, 6.25% in action and 23.5% in maintenance. Inactive participants perceived that their laziness prevented them from being physically active. Meeting friends was the most important facilitator for participating in physical activity. The individuals who married, younger, lower body Mass index, having no chronic disease, and those with past history of exercise were more likely to adopt, initiate and maintain regular physical activity. Regression analysis showed that the greater knowledge of physical activity, higher Perceived health benefits, more Self efficacy were associated with physical activity.Conclusion: Knowing the facilitators and barriers factors of physical activity in elderly would help to implement any future intervention for this group of people.

Background & Objectives: Mental health is one of the most important public health issues, and it has major contribution in decreasing global burden of diseases .the objective of this study was to estimate the point prevalence rate of mental disorders in the population aged 18 years and over in Kashan city in 2009.Methods: A classified- randomized sampling method was used. The General Health Questionnaire and clinical interview were employed to determine of mental disorders. Data were analyzed by using Spss v. 16 and OR, and Chi-square test.Results: The overall prevalence rate of mental disorders in Kashan was estimated (29%) (Female=35.5%). The most prevalent disorders were mood disorders and anxiety disorders (9.3%) and (4.7%) respectively. In total five hundred-five (505) individuals with mental disorders, 32.1% had mood disorders, 25.6% had anxiety disorders, 4.2% had psychotic disorders, 3.4 % had neurological disorders, 3.4% dissociative disorders and 23.7% had other disorders. In this study 7.8% of subject had one mental disorder at least. The prevalence rate was high in people aged 56-65 years (35.8%) and widow (35.8%), illiterate (42.8%) and unemployed (38.8%). There were statistically significant differences between genders, education, and occupation and marital status.Conclusion: Mental disorder has a priority for any intention intervention by health policy makers. It should be taken into account for any future agenda by ministry of health.

Background & Objective: Clinically Chronic Allograft Dysfunction (CAD) is characterized by a progressive decline in Glomerular Filtration Rate (GFR) over time, the pattern of disease progression determined by the five-stage model. In this paper, we used Erlang and Hypo-exponential distributions as Phase- Type distributions to describe hazard of kidney failure at over time in RTR with CAD.Methods: In a single-center retrospective study, 214 patients with RTR with CAD were investigated at the Emam Hospital of Urmia University of Medical Sciences from 1997 to 2005. Kidney function at each visit assessed with GFR and categorized based on NKF and KCOQI staging system.Results: The estimated hazard rates of disease progression from stage 1 to 2, 0.0378; from stage 2 to 3, 0.04; from stage 3 to 4, 0.0458; and from stage 4 to 5; 0.0541 were respectively based on each expected month. This estimates yield a mean waiting time of disease progression from stage 1 to Kidney failure or dialysis 91.63 month. The 18th, 58th, 118th and 155th months of death-censored graft survival were 0.99, 0.75, 0.25 and 0.10 respectively.Conclusions: The findings of this study are compatible with hyper filtration theory in chronic kidney disease and give us more detailed information about the daynamic process of disease which would help to manage it effictevliy.

Background & objectives: Cutaneous leishmaniasis (CL) is an endemic disease in district of Bam. It has created considerable concerns by people and health authorities. The objective of this study was to assess the effect of the earthquake and costs of prevention on CL prevalence after earthquake.Methods: This research is based on a natural intervention, in which the information related to the costs and prevalence of CL were collected and analyzed three years after the earthquake (2006-2008) and then compared with similar data three years before the earthquake (2000-2002) as control group.Results: the earthquake increased the CL prevalence approximately 5.2 fold, although the cost of prevention had no significant effect on control of disease. The average cost of prevention was determined to be two US dollars per capita during the years after the earthquake. It figures up an overall estimation of 600000 US dollars for the three years after the earthquake. Meanwhile the cost of prevention before the earthquake was determined less than 5% comparing to after earthquake.Conclusions: The findings of this cost-analysis showed that the current and conventional methods of CL prevention seem not useful. It could be concluded that current preventive measures such as spraying and impregnated bed nets particularly in natural disasters would have no effect on control of disease. Further researches are needed to find out the best method of prevention of CL disease. At present, it seems that early case-finding and prompt treatment of cases would be a proper method to control anthropometric CL.

Background & Objectives: The aim of this study was to investigate the effects of fish oil containing diet versus Iranian fat consumption pattern and standard diets on serum glucose and insulin sensitivity in Wistar rat.Methods: Thirty female Wistar rats were randomly allocated to three dietary groups: a standard diet (containing soy bean-oil), diet containing fish oil and diet containing mixed oil which was designed based on Iranian population fatty acid intake. Dams in each group were fed one of the diets during pregnancy and lactation and the pups were also weaned onto the same diet. Fasting serum glucose (Photometry) and insulin (ELISA) in pups were assessed and insulin sensitivity calculated on puberty.Results: Fasting serum insulin in fish oil-fed group was significantly less than two other groups (P=0.018) and insulin sensitivity in fish oil-fed rats was significantly more than two other groups (P=0.002).Conclusions: It seems a diet containing fish oil (rich in long chain omega-3 fatty acids) causes more insulin sensitivity comparing to diet containing soy bean oil (rich in omega-6 fatty acids) and diet with Iranian population fatty acid intake pattern (rich in saturated fatty acids).

Background & objectives: Cardiopulmonary bypass often causes a stress hormonal response with subsequent changes in hemodynamic and organ perfusion. Human studies involving cardiopulmonary bypass have shown that very low doses of ketamine can attenuate inflammatory and stress markers, without adverse effects. The aim of this study was to investigate whether low dose infusion of ketamine have hemodynamic stability effect in coronary artery bypass surgery.Methods: In this double blind-controlled trial, 50 patients undergoing on-pump CABG were randomly assigned to receive either 1.25mcg/kg/min of ketamine infusion (Ketamine group, n=25) or normal saline infusion (Control group, n=25) during 48 hours after induction of anesthesia. hemodynamic measurement including blood pressure, heart rate, central venous pressure, cardiac output, cardiac index, systemic venous resistance, arterial blood gas and lactate were measured previous to induction (T1), 4 h, 24h, and 48h after the surgery (T2, T3 and T4). The data were evaluated with using of variance analyzing test and repeated measurement.Results: There were significant interaction effect between time (pre operation, 4, 24 and 48 hours after operation) and group of study (ketamine and placebo) in assessment of systolic blood pressure (p=0.0001), diastolic blood pressure(p=0.0001), heart rate (p=0.004), central venous pressure (p=0.0001) and lactate (p=0.035). These indicate that ketamine caused decrement in tissue perfusion. Those interactions were not statistically significant for other parameters (p>0.05).Conclusions: low dose ketamine during and 48 hours after operation not only didn't show hemodynamic stability effect but also decreased tissue perfusion slightly.

Rapid changes in epidemiologic features of infectious diseases have made it an inevitable need for health professionals to have access to the information about the latest situation of these illnesses. The WHO reports based on data from around the world can provide valuable intensive information. Based on the 2008 report on AIDS; the global percentage of adults living with HIV since the year 2000 has been stabilized; the rate of new cases is increasing in many countries, but in a global view, this desired trend is overshadowed by the surging trend in other countries. In the recent decade, the annual mortality of AIDS has been diminished. In 2007, 68% of the patients still live in Sub-Saharan African countries and 75% of mortalities have been attributed to this region. This report, besides referring to significant achievements in controlling AIDS, still declares some worries in some aspects. There are some documents showing that more attention must be paid to some issues in our country: First, an "All aspects" approach for prevention of new cases and second, acceptance of the "harm reduction" concept in relation to sexual high risk behaviors likewise accepted in drug abuse, and therefore revising methods and coverage of sexual training.