Cohort Profile: The Golestan Cohort Study—a prospective study of oesophageal cancer in northern Iran

Authors: Akram Pourshams, Hooman Khademi, Akbar Fazeltabar Malekshah, Farhad Islami, Mehdi Nouraei, Ali Reza Sadjadi, Elham Jafari, Nas Rakhshani, Rasool Salahi, Shahryar Semnani, Farin Kamangar, Christian C Abnet, Bruce Ponder, Nick Day, Sanford M Dawsey, Paolo Boffetta,,and Reza Malekzadeh

?How did the study come about

The earliest reports of high incidence of oesophageal cancer (OC) in the northern parts of Iran date back to the early 1970s. A population-based cancer registry was established in 1969 as a joint effort between Tehran University and the International Agency for Research on Cancer (IARC). This registry confirmed the high incidence of OC in the eastern portion of the Caspian Sea littoral, in the area that is now known as Golestan Province. The highest incidence rates were reported from the semi-desert plain settled mainly by people of Turkmen ethnicity in Gonbad and Kalaleh counties, with estimated incidence rates of 109/105 among men and 174/105 among women (adjusted to the 1970 World Standard Population). The registry also showed low incidence of OC in the nearby Gilan province, 300 km to the west of Golestan, with incidence rates of 15/105 and 5.5/105 among men and women, respectively. A series of studies were conducted in the region in the 1970s, but they were not conclusive in explaining the very high rates. However, they pointed to several factors, including: (i) a diet deficient in fruits and vegetables; (ii) low socio-economic status; (iii) thermal injury from consumption of very hot tea; and (iv) carcinogen exposure from lifestyle factors including opium consumption.The high incidence of OC in Golestan was confirmed by a recent screening study

?what does the study cover

:The primary aims of the GCS are

To provide a model for population-based studies in a country in economic and social transition based on collaboration between local health workers, local health authorities, national research centres, national government and international research institutions