Study Rationale


Objectives and Outcomes of Interests

Data Collection

Funding and Governance

About The PERSIAN Cohort

The Prospective Epidemiological Research Studies in IrAN (PERSIAN) is a nationwide cohort study launched in the year 2014 in an attempt to encourage research in the fields of medicine, epidemiology, health, and nutrition. PERSIAN has empowered medical schools around the country with the necessary resources to take part in the study, in order to identify the risk factors related to the most prevalent chronic diseases in Iran, with the ultimate goal to reform the health system and enhance the health of Iranians, while contributing to the world’s medical knowledge.

Although the name PERSIAN Cohort mainly refers to the most extensive adult component, birth, youth and elderly components are also simultaneously being carried out in different parts of Iran. The PERSIAN Birth Cohort involves pregnant women and their newborn infants to investigate the relationship between genetic, environmental and social factors on human development, while the PERSIAN Youth Cohort focuses on psychiatric disorders and substance abuse. The PERSIAN Elderly Cohort, the so far smallest component, studies the aging process. (Learn more about the PERSIAN Birth, Youth and Elderly Cohorts under the Parallel Studies tab.)

Rationale for the PERSIAN Cohort

Health of populations is not static; it has a changing trend that should be continuously measured, monitored, modified, and evaluated in a cycle. Accordingly, evidence–based health policies should also be updated and tailored to the continuously changing needs and priorities of a community, and their cost-effectiveness and efficiency should be evaluated on a regular basis.

In Iran, similar to many other developing countries, there has been a shifting trend in the prevalence of diseases from communicable diseases and those passed from a mother to her child, towards non-communicable diseases, calling for action and reform in the health system. For health policies to be evidence-based, there needs to be adequate research performed in the field.

Today, many chronic diseases, such as heart disease, cancers, respiratory diseases, etc. are the leading causes of death in Iran. Although a large amount of research has been done thus far, unraveling the causes of many chronic diseases; however, much of this knowledge is based on studies in the West, and does not generally suffice to explain much of the large geographic differences in disease rates around the world, between different countries, and even within one country. Consequently, the etiology of many common chronic diseases in Iran is still poorly understood, and there is still substantial uncertainty about the impact of many common risk factors to population mortality.

Among epidemiological research methods, interventional studies and prospective cohort studies are the most credible. Cohort studies are necessary for investigating the determinants and risk factors of major diseases. Since the mid-1900s, a number of large cohort studies such as the Framingham Study, Nurses’ Health Study, the Asia- Pacific Cohort Studies Collaboration, and the Alberta Cancer Board were launched mainly in developed countries, enhancing the general medical knowledge about the distribution and causes of major diseases, disabilities, and mortality. Similar studies, however, have been rare in developing countries.

In Iran, the Gastro-Esophageal Malignancies in Northern Iran (GEMINI), was launched in the year 1996, with the aim of investigating esophageal and stomach cancers and their determinants. Today, the findings in GEMINI have gone much further than its original goals, highlighting the high and increasing prevalence of cardiovascular diseases, cancers, and injuries in North Eastern Iran. About 50% of cohort deaths are due to ischemic heart disease and cerebrovascular accidents, while 50% of people are hypertensive, and about 6% of deaths are due to accidents. The results of GEMINI have made it clear that it will be incredibly important and rewarding to launch a large scale national cohort—the PERSIAN Cohort—to investigate the contributing factors and causes of various chronic diseases in Iran, in order to plan for effective interventions for their prevention and treatment.


PERSIAN Cohort is a prospective study aiming to include 170,000 men and women throughout Iran. Originally intended to be carried out in 10 geographically distinct areas, the PERSIAN Cohort has now stretched to 17 regions of Iran, chosen based on local disease patterns, exposure to certain risk factors, population stability causes of death, local commitment and capacity. All individuals 35-70 years of age in the selected sites are recruited and those who agree to participate will be included in the study. 

PERSIAN Objectives and Outcomes of Interest

The health-oriented and research-oriented objectives of the PERSIAN Cohort are divided into two categories as followed:

Research and Public Health Objectives:

  1. To determine incidence/ incidence rates of different non-communicable diseases or outcomes
  2. To estimate the risk and protective factors of non-communicable diseases in a representative sample of middle aged Iranian population
  3. To determine all-cause mortality rates, as well as specific mortality rates of the leading causes of death
  4. To evaluate the relationship between genetic, life style / socioeconomic status and environmental risk factors and the most important non-communicable diseases by case cohort and nested case control designs that will be implemented on the cohort infrastructures
  5. To evaluate time trends of lifestyle and environmental factors and the outcomes of interest in the different cohort sites of Iran
  6. To assess the relationship between genetic markers and NCDs and comparing them among the different Iranian ethnic groups
  7. To evaluate the effectiveness of the most relevant interventions, and to explore the effectiveness of novel interventions, for reducing important non-communicable outcomes through community interventional trials that will be implemented on the population subsets

Health System Research objectives:

  1. To design/improve and optimize different Health Information Systems such as a Cancer Registry, Death Registry, Hospital Information System, etc.
  2. To improve the quality of health care services
  3. To build a population-based research infrastructure for medical universities and to disseminate the concept of “Health System Research” in medical education
  4. To enhance national collaborations between medical universities and health research institutes for joint medical and epidemiological research projects
  5. To establish the largest biobank in Iran for basic and genetic scientific research and discovery of biomarkers and other biological determinants of disease
  6. To establish a practical field for research and training of medical students, residents, and fellows
  7. To enhance international collaborations with recognized medical universities and research institutions in order to plan joint projects, and train students and young researchers

Outcomes of Interest

  1. Deaths by cause
  2. Incidence of major non-communicable diseases including cardiovascular diseases, cancers, and chronic digestive, respiratory, renal, hepatic, and neurological diseases
  3. Trends in major risk factors including anthropometric, physiological, life style, and environmental factors

Data and Specimen Collection

Questionnaires and Physical Examinations

As part of the data gathering for the PERSIAN Cohort, a comprehensive interviewer-administered electronic questionnaire consisting of 3 major sections—General, Medical and Nutrition—has been developed, encompassing many different aspects of an individual’s life, which may have an impact on their health status. In addition to the questionnaires, a physical examination is performed and pulse, blood pressure and anthropometric measurements are also recorded.

Data is gathered at each location using a pre-designed software and pooled into a Central Data Bank. Topics covered in the PERSIAN Cohort questionnaire are as followed:

General Questionnaire

  • Demographics
  • Socioeconomic Status
  • Lifestyle Factors
  • Occupational History
  • Physical Activity
  • Circadian Rhythm
  • Mobile Use
  • Pesticide Use

Medical Questionnaire

  • Past Medical History
  • Medicine Use (Past and Present)
  • Family Medical History
  • Obstetrics and Gynecology History (Women)
  • Oral Health
  • Personal Habits (Drugs and Alcohol)

Nutrition Questionnaire

  • Food Frequency Questionnaire
  • Dietary Habits
  • Water Use
  • Supplements

Biological Samples

Blood, hair, and urine samples are collected from participants at the initial data gathering and stored in a biobank. Read more about the PERSIAN Cohort Biobank

Funding and Governance

The PERSIAN Cohort is governed by a Central Committee, led by Dr. Reza Malekzadeh, the Deputy of Technology and Research at the Ministry of Health and Medical Education (MOHME). In addition, principle investigators (PIs) from each university also govern their own site. While the MOHME provided the necessary funds to set the cohort infrastructure at the cohort sites, each university is responsible for their funding, with some support from the MOHME.


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Contact us

Digestive Diseases Research Institute (DDRI)

Shariati Hospital, Kargar Shomali Ave. Tehran, 14117-13135 I. R. Iran
PO.Box: 1411713135

DDRI Tel: +98-21-82415000
Cohort Tel: +98-21-88229011

Fax: +98-21-82415400

© 2017 Prospective Epidemiological Research Studies of the Iranian Adults