Yazd Health Study (YaHS) is a population-based cohort study of 9962 individuals aged 20–70 years, established in November 2014 in the Greater Yazd Area. This study aims to investigate the changing incidence of a variety of chronic illnesses and associated risk factors in an area with one of the highest rate of chronic illnesses in Iran. The family history of major non-communicable diseases (NCDs) is collected to investigate the pedigree of patients in the Yazd population. A biobank is established to collect blood and extract DNA samples from the participants for future genetic epidemiology studies. Geocoding of all participants is performed to prepare a database for spatial epidemiology investigation. At baseline, trained interviewers collected detailed information on personal and dietary habits, physical activity, medical history, mental health status and social well-being of the participants and also anthropometric measurements (response rate = 94.9%). All participants were invited to attend a referral laboratory to provide blood samples and 4010 (40%) of them did so. In the second phase of the study commencing in November 2015, the Yazd biobank (Zist Bank-e-Yazd-ZIBA) was established and a detailed nutrition study (Taghzeh Mardom-e-Yazd-TAMYZ) has been ongoing since the establishment of the biobank. It is anticipated the data collection phase of the nutrition study will be completed by the end of 2017. Data on a variety of outcomes measures will be collected from the cohort through a combination of in-person surveys, collected every 5 years, and through annual record linkage with the integrated hospital information system (SEPAS) of the area and data from cancer and vital statistics registries of Yazd province. YaHS provides useful evidence for research in social epidemiology, NCDs epidemiology, spatial epidemiology and genetics epidemiology. Information on accessing YaHS data and other resources can be found at: [http://yahs.ssu.ac.ir]. The increasing burden of disease associated with non-communicable diseases (NCDs) is a major public health challenge worldwide. Every year, 38 million people die from NCDs in the world, and 82% (29 million) of these premature deaths attributed to NCDs occur in developing countries, with an increase in the recent years.1,2 In Iran, a very high burden of disease can be attributed to NCDs: 45% of the burden of disease in men and 33% of the burden of disease in women is related to NCDs. Overweight and obesity, hypertension, low physical activity, drug addiction and dyslipidaemia are among the most important risk factors.3 Yazd province, located in the centre of Iran (Figure 1), has experienced rapid economic development and environmental and lifestyle changes over the past two decades. Over the same period of time, the prevalence of known risk factors for NCDs has increased rapidly. It is estimated that about one-third of Yazd inhabitants are suffering from metabolic syndrome (MetS);4 85.0% of the population (20–74 years old) have at least one and 59% have two relevant risk factors for chronic disease. Hypercholesterolaemia was reported in 12.1% of the population, dyslipidaemia in 58.5%, high blood pressure in 25.6% and cigarette smoking in 13.1%. Overall, 16.4% of the population is obese and 43.3% of men and 62.1% of women have excess weight.5 A recent study on prevalence of obesity and overweight among adults aged over 30 years in Yazd showed the prevalence of obesity and overweight were 9.5% and 29.0%, respectively, and the percentage of overweight was greater in women than men and in urban areas compared with rural areas.6 A study in 2012 revealed that the prevalence of type 2 diabetes mellitus (DM) has reached to an alarming rate at 16.3% in Yazd,7 which is more than double the prevalence of diabetes in Iranian adults aged above 30 years.8–12 It is also reported that the age-standardized incidence rate (ASR) of cancer in Yazd province has increased significantly over the period 2004–09, from 85.2/105 to 104.7/105 in 2009, and the rate of change in Yazd province is higher than in other provinces.13 Environmental and social risk factors contribute to NCDs and can be prevented. Environmental risk factors of relevance to the Yazd population include air pollution,14 solar ultraviolet radiation15 and indoor radon.16 Cigarette smoking is the most important preventable cause of death worldwide and is prevalent risk factor in the Yazd population: around 31% of adult males smoke cigarettes regularly17 and 14.2% of pregnant women are passive smokers in Yazd.18 The overall trend of the motor vehicle accident rate in Iran has reduced over the past few years, but the motor vehicle accident rate in Yazd is still high (37.6/105).19 Further, riding a motorcycle is a very popular mode of transport in Yazd, but few motorcycle riders use a helmet and multiple trauma in this group is prevalent.20 Immigration has played an important role in the area population growth of Yazd over the three past decades, with an 11-fold increase over this time.21 Just over the past 5 years, 57656 people have migrated to Yazd from other parts of Iran and overseas.22 Jobs in the industrial sector and other economic opportunities are among the major reasons for migration to Yazd. With the ageing population and unhealthy changes in lifestyle and environment, it is expected that the incidence and mortality rate of NCDs will increase in the future. This study provides an opportunity for researchers to investigate the contribution of environmental and lifestyle risk factors on the incidence of NCDs. Although several studies have explored the determinants of prevalent chronic diseases in the Middle East, including Iran,23,24 a limited number of large-scale prospective population-based studies have been conducted in the Middle East, e.g. the Golestan Cohort Study.24 Consanguinity (family) marriage ratios, an important factor contributing to increased congenital malformations, is 46% in Yazd,25 which provides a unique opportunity for genetic epidemiology studies. Yazd Health Study (YaHS) is a large-scale population-based prospective cohort study commissioned by Shahid Sadoughi University of Medical Sciences in response to the ‘National Action Plan for Prevention and Control of Non communicable Diseases and the Related Risk Factors in the Islamic Republic of Iran 2015–2025’, which has proposed 13 key targets.26 The recruitment phase of YaHS started in November 2014 and concluded in April 2016. The follow-up surveys will be conducted every 5 years. This study aims to investigate the changing incidence of a variety of chronic illnesses and associated risk factors in an area with one of the highest rates of chronic illnesses in Iran. The family history of major NCDs is collected to investigate the pedigree of patients in the Yazd population, with over 45% consanguinity marriage. A biobank is established to collect blood and extract DNA samples from the participants for future genetic epidemiology studies. Geocoding of all participants is performed to prepare a database for spatial epidemiology investigation. Ethical approval was obtained from the Ethics Committee of Shahid Sadoughi University of Medical Sciences, No. 17/1/73941. Written informed consent was obtained from all participants. Yazd province is located in the centre of Iran. According to the latest Iranian National Census (2011), it is populated by 1074428 inhabitants, with the population growing at an average rate of 1.63% from 2006 to 2011. The contribution of this province to Iranian gross domestic product (GDP) is estimated at 1.54% in 2009. A majority of the population lives in the urban area (82.8%). Less than half (42.6%) of the workers are employed in industries. The literacy rate is 87.8% in this province, and there were 94076 students (8.6% of population) studying at universities located in the province in 2015.27,28 Greater Yazd area includes Yazd city, which is the capital of Yazd province, and three annexed cities—Shahediah, Zarch and Hamidia—and surrounding villages (Figure 1). The population of Greater Yazd area is 582682: (49% of the population is women and there are 168458 families, and the population is highly urbanized (94.5% live in urban areas).22 Yazd is the first mud clay city in the world, and is well known for its preserved historic sites and was recently inscribed a world heritage by UNESCO.29 In 2015, 64850 foreign tourists visited Yazd.27 Yazd is the main residence of Zoroastrians, who are the original inhabitants or aboriginal people of the country. Zoroastrians do not marry outside their faith, so they are suitable for genetic epidemiology studies. Yazd is located in the border of the Loot desert and has an average rainfall of around 60 mm per year.30 with annual average humidity of less than 43%.31 Due to its harsh climate, the area under agriculture is very limited and only 10% of the population work in the agriculture sector.27 In all, 10000 residents of Yazd city aged 20–70 years were selected using a two-level clustered random sampling method according to WHO STEP guidelines.32 First, 200 clusters were selected randomly according to city postcodes. Second, the interviewers contacted the assigned addressees and, after explanation of the study, arranged a meeting time at their residences. The interviewers then went to the neighbourhood of the first addressee according to the study protocol, to interview 50 participants assigned to each cluster: 25 men and 25 women; five persons in each 10-year age group. On the rare occasions that there was more than one family residing in an address with a unique postal code, the interviewers questioned all eligible residents who consented to participate. Furthermore, anthropometrics and blood pressure measurements were carried out after enrolment and during the interview. To avoid under-representation of certain age groups, e.g. 20–29 years and 60–69 years, men and employed persons, and according to the STEP guideline, each cluster consisted of 10 persons in age groups as follows: 20–29, 30–39, 40–49, 50–59 and 60–69 years. The inclusion criteria were age 20–69 years at the time of interview and informed consent to participate in the study. Those who were guests and not residents of the recruited addresses were excluded. A total of 100 interviewers attended a 1-day workshop to become familiar with interviewing techniques, the study protocol, the questionnaire, anthropometric measurments, measuring blood pressure and measuring pulse. Ethical considerations in conducting interviews and the correct method of obtaining informed consent were also taught and practised in the workshop. After the workshop, candidates were examined and, if they passed the theory and practice sections, they were registered as eligible interviewers for the YaHS study and their photo ID cards were issued. The process was photographed and published at Instagram® under yazd_health_study. Iran has had an integrated medical education and health services system, as capacity building for postgraduate students is an important goal for the system.33 The YaHS study provided a unique opportunity for volunteer postgraduate students to participate in a community-based study and to use the collected data for their treatise and other research projects. This new approach is particularly helpful where research grants are limited for postgraduate students.34 The per capita research budget for postgraduate students is around USD 1200, which is not enough for students to complete a well-designed and well-administered study. To increase the response rate of the study, a city-wide media campaign including banners and radio and TV teasers were prepared. Those who agreed to participate in the study and signed the informed consent forms were interviewed at their place of residence (response rate = 94.9 %). The recruitment phase commenced in November 2014 and finished in April 2016. After finishing the interviews and measurement of anthropometrics and blood pressure, an invitation card to attend Yazd Central Laboratory for blood tests was given to each participant, asking them to attend the laboratory before 9 am and after fasting from 10 pm the previous night. The cards contained a unique barcode identifier in order to minimize errors at the laboratory. Using uniform venojects, 15 ml fresh blood was taken from each participant; 10 ml was stored for the Yazd biobank (Zist Bank-e-Yazd-ZIBA) and 5 ml was used for blood and biochemistry tests using calibrated instruments and biochemistry kits (participation rate 40%). All samples were kept at −4°C, processed within 6 h and stored at -75°C thereafter. At biospecimen collection, information was collected on date and time of sample collection and intake of selected medications over the past 24 h and during the preceding week. Geocoding of all participants is performed using Garmin GPS device model MAP78S (Garmin International Inc., Olathe, KS, USA) to prepare a database for future spatial epidemiology investigation. The baseline demographics of the study participants are presented in Table 1. Of the total respondents (9965), 49.7%were men and 90% were from the urban areas; 26.2% had primary or less education; 10.3% of the participants had migrated from within the province and 12.8% from other provinces; 94.5% of had public health insurance; and 2.2% of the study participants were Zoroastrian. Most participants (85%) were married; 68.2% of men and 12.2% of women were employed; 50% of women were housewives; 78.6% of the participants were home-owners; and 78.5% live in a residencel with more than 100 m2 area. Distribution of demographic characteristics of Yazd Health Study participants in 2014 Distribution of demographic characteristics of Yazd Health Study participants in 2014 Map with location of Greater Yazd Area in Iran (Area 2397 km2). The research team will repeat the survey and measurements every 5 years to obtain longitudinal data on changes in various measured factors. Further, YaHS uses data from population-based registries and linked outcome data from the aggregated hospital information system (Samanah Electronici PArvandeh Salamat-SEPAS) which covers 100% of public hospitals and the majority of private hospitals in Yazd province. Deaths, cancer incidence, surgeries, ischaemic heart disease, stroke and other outcomes will be extracted from SEPAS using the National Identifier number of each participant to link data. National ID is a unique identifier of each Iranian citizen which has been widely used in almost all national databases. This will provide an opportunity for data linkage studies in the future. New variables may be added in the future waves of the study, according to the recommendations of health experts. A validated questionnaire including 300 questions plus anthropometrics, blood pressure and vital signs was filled in by trained interviewers and includes the following sections; a) demographics, b) physical activity, c) sleep quality and quantity, d) mental health, e) past medical history of chronic disease and surgical operations, f) dental health, g) history of accidents, h) dietary habits, i) occupation and social life, j) traditional smoking and drug health and quality of including for A of and the was by the and the questionnaire was on 50 participants. was and the questionnaire was anthropometrics, blood pressure and were measured and in three before and during the Table 2 the variables collected in the used and data collected in the first of Yazd Health Study used and data collected in the first of Yazd Health Study age-standardized baseline characteristics of Yazd Health Study participants 2014 age-standardized baseline characteristics of Yazd Health Study participants 2014 was measured using an and with of on the of the and with and percentage was measured using the same according to All anthropometric measurements were performed before commencing the after completed one-third of the questionnaire and for a time after of the questions in the to the study was measured in a using a on a to the To participants were and their in the and were the to which the was The were calibrated by a was to the using and participants were in the was also measured over the of the with an of The was measured using a around the of the the it and not on the was using and measurements according to the following pressure was measured in a after of the interview questions were so the had been in a for at least at this and blood pressure measurements were three with 5 each using which were calibrated The of the second and measurements were as blood pressure and Laboratory measurements consisted of fasting blood complete and blood and also rate All measurements were according to a laboratory using kits and calibrated and have been in the Yazd and known as in This of YaHS of a questionnaire of and All participants of YaHS were in which started in To over participants have been This will provide a of data to through and YaHS data. 2 a of YaHS data All interviewers were trained in to questions and complete the The used in was a of a validated used for and Study 10 questions to of in the were added to the original in Further, the used in was to be in its original the questionnaire to a multiple one in two questions about each the of of per or the was in the past and of taken each of the data collection process of Yazd Health To increase the and of the of as a using a photo for all participants to were to of intake of all on 10 response from or less than a to or more per The of at each intake was using questions with five The were according to each were also interviewed using a questionnaire about the of the following and The were on and for the study. The data was completed to minimize The data phase after a of was was by the and an of the research of the Data and was under of an information and a Data from death and cancer registries as well as SEPAS system were linked to the YaHS database after finishing the recruitment phase with a The study protocol, information and consent forms were by the of Shahid Sadoughi University of Medical Sciences, and several studies including the Iranian Health Study their from YaHS At baseline, and of YaHS participants reported a history of hypertension, and The estimated age-standardized and blood were and of adults in this population were estimated to be or The prevalence of overweight = was and of obesity 30 was of and was less than two per in and of of the participants or more per and had more than two of per week. less than one of per was reported by of the participants. was more than per by A total of of participants had a low of physical and women %). The overall age-standardized prevalence of smoking was in men and in smoking was reported by and use by of the participants. vehicle were reported by of the also and of the population reported using a on public but reported using a in a private Table baseline characteristics of the participants. of YaHS are as follows: the first population-based prospective study with collection of a of data measured in a building capacity for of follow-up and longitudinal for the of multiple link with the other health and of health urban and rural and samples of YaHS are as follows: of a of follow-up so may be for follow-up it is that data collection be by the health system the population of the study was the study not to investigate and then longitudinal from to or from to biochemistry and blood tests were limited to of have been who the samples and who did in of limited information about pedigree the first data were collected over more than the original time data were outcomes will be extracted from an aggregated to data on use and were not In YaHS has provided useful and data for use in social epidemiology, spatial epidemiology, NCDs epidemiology, genetics epidemiology and health services reported the baseline and of YaHS under the Yazd Health Study which is a study. survey is for are certain to obtain useful data in the The data collected by Yazd Health Study are not but can be under of and research are and and can be to the first at that there is a for related to data research will be in the first with the on data by the YaHS which will all related to data YaHS at All YaHS are on its at: = = Yazd Health Study (YaHS) is a large-scale population-based prospective cohort study with 10000 registered in Yazd Greater Area located in Iran, with Yazd has experienced rapid environmental and lifestyle changes over the past two decades. YaHS greater for research surrounding lifestyle factors including unhealthy physical drug addiction and which an important role in non-communicable disease development and YaHS genetic epidemiology studies on and of various chronic diseases in the Middle A variety of outcomes measures will be collected from the cohort through a combination of in-person surveys, collected every 5 years, and annual record linkage with the integrated hospital information system and cancer and vital statistics The data collected can be under of and YaHS provides a unique opportunity for postgraduate students to use for their treatise and other research projects. The study was by Shahid Sadoughi University of Medical Sciences and by the for at the Iranian of The research of the the study under No. in YaHS Yazd people for in the study, students for in and of the of the study, and Yazd Central Health workers and for their and to who the of YaHS during a of Golestan Cohort Study in to for the of
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Mirzaei et al. (2017) studied this question.