The frequency of asthma and its related factors: results of the enrolment phase of Tabari cohort study.

Introduction: A large portion of the world's population has asthma. This study aimed to ascertain asthma prevalence and related factors in the Tabari cohort study (TCS).

Methods: The TCS included 10,255 35-70-year-olds from urban and mountainous Sari (northern Iran) between June 2015 and November 2017.