first phase report of the golestan cohort study;a prospective study of cancers and chronic diseases risk factors in 50,000 inhabitants of north eastern of iran

background: the incidence rate of esophageal squamouse cell cancer (escc) in eastern part of golestan province in iran is among the highest ones in the world. in order to discover the factors interplay in high rate of escc incidence, several case-control and cross-sectional studies were established in this area.as a cohort study has priority in detecting risk factors of a disease, a 10-year prospective cohort study was conducted in this area. materials and methods: 68,024 individuals of residents in eastern part of golestan province in the range of 40-75 year-old were invited to participate in the study. in rural areas, all the eligibled subjects were invited while in gonbad city; a randomized systematic clustering sampling was conducted based on family numbers. results: of 50045 subjects, recruited in the study, 21,241 (42%) and 28,804 (58%) individuals were male and female, respectively. the mean age of participants was 52.12 â± 9.1 years. about 23.9% and 76.1% of participants were residents of gonbad city and rural areas, respectively. conclusion: eastern part of golestan province has one of the highest incidence rates of escc in the world. a 10-year cohort study could lower the incidence rate of escc by identifying and controlling the related risk factors.