Iranian Journal of

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Knowing the population size of rare diseases or special subpopulations like injection drug users (IDUs) is one of the most important challenges in public health and health surveillance systems but it is difficult to estimate these groups. During the last few years, new methods have been suggested to estimate hidden or hard-to-reach populations, one of which is the network scale-up method (NSUM). The NSUM itself includes measuring the personal network size and estimating the prevalence of hidden and hard-to-count populations. In this paper, we basically discussed the indirect methods of calculating the population size, and the history of NSUM and its concepts, and then addressed the estimation of hidden populations with NSUM and the applicable notes for such populations.

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Recently, capture-recapture studies have been used and researchers tend to use these studies in the health field. Therefore, we discussed the basic concepts of these studies. First, we described capture-recapture studies. Then, the important assumptions and calculations were presented according to the close population assumption. Statistical formulas were presented for two-capture methods and dependency between the two lists was discussed. Then, we addressed more than two capture methods.

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financial protection against health expenditures is a major goal of health system policymaking. governments have focused on the risk that high health expenditures pose to the financial security of deprived and vulnerable populations. Health systems need to be sure that people receive health services and are protected from the financial burden of health costs. There is no accepted standard for measuring the degree of financial protection. In the literature, there are different approaches to measure the degree of financial protection. Measuring the extent of financial risk is complicated by the fact that the significance of a given risk depends on both the size of the risk and the economic status of the person incurring the risk. Another reason for this complication is that financial risk can also affect the health status. The seriously ill may not receive adequate care if the financial burden on them contributes to a decision not to seek care. Their injury from a lack of risk protection, therefore, may show up as diminished health status and not as a financial loss. The aim of this article is to provide the methodology of the assessment of financial protection against health costs with focus on catastrophic health expenditures. First, we describe and explaine the methodology of measuring the expenditures (based on the WHO approach). Then, we interpret variables used in estimating these costs. Finally, overall discussion and conclusions will be provided in relation to the subject.

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The time series is a collection of observation data that are arranged according to time. The main purpose of setting up a time series is to predict future values. The first step in time series data is graphed. Using graphs can provide general information such as uptrend or downtrend, seasonal patterns, periodic presence, and outliers in time series graphs. After graphing the data, if a good forecast is required, stationary data can be used. Differencing or decomposition methods can be used to make the data stationary. Then, a correlogram can be used to identify the order moving average and autoregressive model. The parameters of the model are examined using T-test. If the parameters are significant and the residue is independence, the predicted values can be evaluated using the mean absolute percentage error.

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Background and Objectives: Managers need the results of scientific researches for executive planning. Considering some methodological errors in reported studies in Iran and the lack of specific and summarized references, this article aims to provide practical considerations in elderly studies.

Methods: In this narrative review, we conducted a comprehensive search in all accessible electronic data bases using “epidemiology” or “methodology” and “elderly” or their synonyms as keywords. Related papers and books were selected. After review, considerable notes were extracted and presented.

Results: Considering attrition, death, and non-response rates in sample size calculation, proportional sampling from all strata, and considering differences in clinical manifestations and diagnosis are important. Matching for main confounders, considering recall bias, creating a quiet and comfortable environment to conduct the interview, allocating a certain percentage of participants to high risks, registering age and other quantitative variables in detailed and non-categorized formats, home visit for interview after receiving informed consent from the elderly or their guardians, interview at the closest location to the elderly’s residence, avoiding long interviews, considering bold and legible words in designing the questionnaire, data re-checking with proxy and documents, applying age and sex adjustment for rates, evaluating the functional status, appropriate interpretation related to odds ratio and considering the cost of the studies are the most essential considerations in aging studies.

Conclusion: Using epidemiological methods with respect to the characteristics of the elderly enhances the quality of the collected data. Well designed studies provide policy makers with reliable evidence for planning.

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In epidemiologic studies, the measurement of characteristics of interest is almost always subject to random measurement error. This error and its effects are usually overlooked by researchers. One of its effects is a widespread statistical phenomenon that is well known as regression to the mean. This phenomenon occurs whenever an extreme group of people is selected from a population based on their measurements of a variable. If a second measurement is taken in this group, the mean of the second measurement will be closer to the mean of the population.  In interventional studies, this increase (decrease) might be regarded as the effect of intervention, when in fact it has had no effect. Ignoring regression to the mean will lead to the erroneous conclusions and interpretation of the results of epidemiologic studies and affects the decisions in evidence-based medicine and planning for preventive and public health measures. This paper highlights the importance of this problem and its effects in epidemiologic studies and the ways to avoid it.

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Good governance promotion in the health sector needs effective policies and evidence-based decision making. Using efficient and effective information is an important issue so that planners will not be confused amid many figures and numbers and also the main problem will not be marginalized. Hence, having a common language and consensus between policy makers and decision makers about the cycle (collecting and processing information, analysis, and judgment) and decision-making tools (criterion, indicator, index, and variable) is an initial and crucial step in evidence-based decision making. The main challenge for creating such an information system is the lack of a common language among scientific and executive experts; so the aim of this study was to provide a perspective of the concept of decision-making and the main components of its cycle and tools and to review these concepts in health care financing system.

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Sampling hidden populations is challenging due to the lack of convenience statistical frames. Since most populations exposed to special diseases are hidden and hard to reach, sampling methods that produce representative and efficient samples from the populations have become a study subject for researches all over the world. Because of the unknown probability of selecting samples in conventional sampling methods and also invalidity of generalizing the results of non-probability sampling methods to the statistical population, the necessity of introducing probability chain-referral sampling methods, such as the respondent driven sampling method becomes imperative. In this article, besides introducing the respondent driven sampling method, some of the advantages of this method as relative decrease of the bias of estimates, declining the non-response rate by paying incentives and allocating weights proportional to reciprocal of the social network size of respondents to produce unbiased estimates are described. Moreover, some disadvantages of this method such as lack of producing differential samples by selecting similar seeds, lack of reaching more efficient method than snowball sampling by implementing this method improperly and lack of achieving to equilibrium by existing weak social networks among members of interested population are stated. Another aim of this article is to compare sampling methods of hidden population with the respondent driven sampling method which are the results of implementing this method in different surveys and existing simulations.

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Case-Cohort and nested case-control designs are the most well-known and cost-effective derivatives of prospective studies. Due to the popularity of these designs in recent years, the aim of this study is to provide a comprehensive and up-to-date description of them with respect to methodological issues such as sampling scheme, effect measure estimation, and analysis strategies. Overall, random sampling of controls in case-cohort and matching for time in nested design are considered their hallmarks. Eventually, decision on a better design depends on study objectives, sub-cohort selection, case and control determination, and method of data collection. It should be kept in mind that any particular study requires unique elaboration and delicate examination to choose from the designs.

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Calculation of Cronbach's Alpha which measures the internal reliability of a tool is easy, but misuse and misconception are widely observed. Common misunderstandings of the Cronbach's Alpha include inability to differentiate between being one-dimensional and consistency, and between raw and standardized alpha. Violations of the assumptions of alpha could also cause an increase or decrease in the calculated alpha. In this paper, we showed that a very large but confusing alpha coefficient could be obtained, particularly when the one-dimensional theory is violated. Also, the use of standard error measurement as an index of the reliability has been presented. Finally, the generalizability of alpha coefficient is also discussed.

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The human approach to health and identification of the factors affecting it over time has changed. Understanding these approaches is helpful in promoting policymaking and good governance can be helpful in the health sector. Biomedical, psychological, health promotion, health determinants, health in all policies and one health are the most important health approaches that have emerged in different years in order. Each of these approaches has many challenges and strengths. Documents and studies show that although these health approaches have been inconsistently addressed in Iran, no specific doctrine has been define to guide the health policies. Therefore, in practice, what seems to be that a biomedical approach to health is the dominant approach in Iran's health system.

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Health and human rights are two inseparable and interrelated elements, whose provision and assurance enhance welfare in any society. Definition of welfare, human rights, and health as indicators of welfare development is controversial which is done in accordance with different approaches and discourses. Although the WHO definition is currently the only definition of health agreed upon by the member states of the Organization, it has been subject to criticism by the international society. In general, the most important criticisms include ambiguity, ideality, limitlessness, lack of comprehensiveness, lack of weighting to aspects of health, being non-operational, reductionism, and lack of a precise definition of the normal condition and disease. These criticisms would expose health systems to some challenges such as increased expectations of people, rapidly growing health expenditure, inconsistent expansion of technology-based systems, increased vulnerability to corruption, and equity and efficiency issues. Identifying and examining these criticisms can lead to a more informed decision to redefine health according to the favorable and context-sensitive discourse of the health doctrine in each country. This short review briefly describes the context and the most important criticisms of the WHO definition of health. Eventually, some policy suggestions are presented for redefining health according to Islamic-Iranian discourse.

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Standard methods for estimating exposure effects in longitudinal studies will result in biased estimates of the exposure effect in the presence of time-dependent confounders affected by past exposure.

 In the present review article, we first described the assumptions required for estimating the causal effect in longitudinal studies and their structure regarding various types of exposure and confounders; then, we explained the bias of standard methods in estimating the causal effect.

Two types of bias, i.e. over-adjustment bias and selection bias, occur in estimating the effect of time-varying exposure in the presence of time-dependent confounders affected by previous exposure using standard regression analysis. Standard regression methods cannot sufficiently modify time-dependent confounders and estimate the total causal effect of the exposure.

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One of the traditional methods used for the analysis of survival data is the Cox regression technique. This method calculates the conditional risk ratio. However, when the aim of the study is to estimate the effect of exposure in the total population level, using these conditional methods is not apposite. Furthermore, the hazard ratio has disadvantages of its own such as being non-collapsible, having the risk of structural selection bias and variability in time. Given the limitations, it is recommended to use the marginal hazard ratio, which estimates the average causal effect of exposure in the total population level.
This study introduces the inverse probability treatment weighting (IPTW) as a method of estimating the marginal causal effect. Finally, to illustrate IPTW method, we used Golestan Cohort Study and estimated the marginal causal effect of smoking on time to death due to the upper gastrointestinal cancer (esophageal-gastric).

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To acknowledge the scientific scholars who have contributed to the advancement of knowledge and service without sacrifice to the homeland, it is necessary to to document their biography in a way to highlight their prominent personal characteristics for next generations.
Prof. Abolhassan Nadim, the retired professor of epidemiology and the founder of modern epidemiology in Iran, holding PhD in Parasitology, Epidemiology and Laboratory Sciences, has carried out brilliant activities in the field of epidemiology and health at national, regional and international levels. His activities have been carried out in various areas of epidemiology and health, and his major activities are in various aspects of Leishmaniosis and phlebotomouses distibution. With more than 45 years of service, most of the graduates of epidemiology in the country, directly or indirectly, had been his students.
A glimpse over the great life of Prof. Abulhassan Nadim, shows that the abundant knowledge, the constant effort and the love and interest in the honest service in their lives are the enlightening of the people who are walking in this way.
 
 

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Concurrent with globalization, some changes have been created in the performance of the universities in developed countries that have turned them into a power source for economic development. In this study, generation changes of Iranian universities in the health sector were analyzed by the layer analysis (CLA) framework. The results showed that the status of universities in Iran is moving from the first and second university generations (i.e. education and research oriented) to the third generation (wealth creation). Too much concentration on indexes such as expert human resources training and number of papers and citations in the Iranian universities has led to stagnation in litany and structural layers. Obtaining scientific authority and technology development requires fundamental evolutions of sciences in deeper layers such as Islamic world view, governance of valuable contexts and evolution in the relationship among higher education and the research and technology system with other sectors.     

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Background and Objectives: In the late 2019, the SARS-CoV-2 virus was identified as the cause of an outbreak of acute respiratory illness known as the COVID-19, which began to spread in the world very quickly. Preventive measures have been a significant issue in preventing the spread of COVID-19. This rapid review study was conducted to summarize selected countries' preventive policies and strategies in the East and Southeast Asia, including China, South Korea, Japan, Vietnam, and Singapore, during the COVID-19 epidemic.
 
Methods: In this rapid review study, the Scopus, PubMed, Embase, and Web of Science databases were searched. The keywords applied in the search strategy were primary health care, public health, prevent* and plan, policy, program, initiative, intervention, measure, and COVID-19 in addition to the name of each country. Furthermore, we searched the World Health Organization (WHO) and the United Nations Development Program (UNDP) websites to retrieve more key sources as grey literature. The relevant data were extracted from the final studies and categorized.
 
Results: After screening, 33 studies met the inclusion criteria. Dominant measures implemented in these countries were categorized into different categories including communication and information, physical distancing, quarantine, monitoring, and testing axes.
 
Conclusion: Education and information, extensive testing and screening, contact tracing, isolation of infected and suspected cases, and observance of physical distancing has been very effective in reducing Covid-19 transmission and its mortality.

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