Despite to high burden of road traffic injuries (RTIs), the RTI epidemiology has received less attention with rare investments on robust population cohorts. The PERSIAN Traffic Safety and Health Cohort (PTSHC) was designed to assess the potential causal relationships between human factors and RTI mortality, injuries, severity of the injury, hospitalised injury, violation of traffic law as well as offer the strongest scientific evidence.

The precrash cohort study is carried out in four cities of Tabriz, Jolfa, Shabestar and Osku in East Azerbaijan province located in northwest Iran. The participants were people who sampled among the general population. The cluster sampling method was used to enrol the households in this study. The PTSHC encompasses a wide and comprehensive range and types of data. These include not only the common cohort data collections such as medical examination measures, previous medical history, bio assays and behavioural assessments but also includes data obtained using advanced novel technologies, for example, electronic travel monitoring, driving simulation and neuro-psycho-physiologic laboratory assessments specifically developed for traffic health field.

A total of 7200 participants aged 14 years and above were enrolled at baseline, nearly half of them being men. The mean age of participants was 39.2 (SD=19.9) years. The majority of participants (55.4%) belonged to the age group of 30–56 years. Currently, approximately 1 200 000 person-measurements have been collected.

PSTHC will be used to determine the human-related risk factors by adjusting for the vehicle and land-use-related factors. Therefore, a lot of crashes can be prevented using effective interventions. Although this cohort provides valuable data, it is planned to increase its size to achieve the highest level of evidence with higher generalisability. Also, according to the national agreement this cohort is going to be extended to several geographical regions in second decade.

The Kharameh cohort study (KHCS) is one branch of the ‘Prospective Epidemiological Research Studies in Iran’, located in the south of Iran. The enrolment phase of KHCS spanned from April 2015 to March 2017, during which urban and rural residents of Kharameh were enrolled in the study. KHCS aims to investigate the incidence of non-communicable diseases (NCDs) such as hypertension, diabetes mellitus, cardiovascular diseases and cancer, and its related risk factors in a 15-year follow-up.

KHCS was designed to recruit 10 000 individuals aged 40–70 years old from both urban and rural areas of Kharameh. Thus, a total of 10 800 individuals aged 40–70 years of age were invited and, finally, 10 663 subjects were accepted to participate, with a participation rate of 98.7%.

Of the 10 663 participants, 5944 (55.7%) were women, and 6801 (63.7%) were rural residents. The mean age of the participants was 51.9±8.2 years. 41.8% of the participants were aged 40–49, 35.2% were aged 50–59 and the remaining 23% were 60–70 years old. Until March 2020 (first 3 years of follow-up), the total number of patients diagnosed with NCDs was 1565. Hypertension, type 2 diabetes and acute ischaemic heart disease were the most common NCDs. Furthermore, the total number of deaths during the first 3 years of follow-up was 312, with cardiovascular diseases (38.7%) as the most common cause of death, followed by cerebrovascular diseases (11.8%) and cancer (16.2%).

The remaining 12 years of follow-up will inevitably shed light on the genetic, lifestyle/socioeconomic status, and environmental risk and protective factors of NCDs.