Methods of sampling and sample size determination of a comprehensive integrated community-based interventional trial: Isfahan Healthy Heart Program

BACKGROUND: The aim of this study was describing the sampling methods and sample size of the Isfahan Healthy Heart Program (IHHP) and its sub-studies in focus.METHODS: The IHHP was carried out between ۲۰۰۰ and ۲۰۰۷ in urban and rural areas in ۳ districts, namely Isfahan and Najafabad (as the intervention areas), and Arak (as the reference area), Iran. It consisted of the ۳ phases of baseline surveys during ۲۰۰۰-۲۰۰۱, interventions between ۲۰۰۲ and ۲۰۰۵, and post-intervention surveys during ۲۰۰۶-۲۰۰۷ on ۴ target groups (adults, health professionals, cardiac patients, children, and adolescents). During ۲۰۰۲ to ۲۰۰۵, ۴ evaluation studies were conducted to evaluate short-term results. An ongoing cohort study entitled the Isfahan Cohort Study was performed on those aged ≥ ۳۵ years at baseline in ۲۰۰۱ to access the risk of cardiovascular disease (CVD) occurrence.RESULTS: Using stratified random cluster methods, ۱۲۵۱۴, ۵۸۹۱, ۴۷۹۳, ۶۰۹۶, ۳۰۱۲, and ۹۵۷۲ adults and ۱۹۴۶, ۱۹۹۹, ۱۴۲۷, ۱۲۲۳, ۳۸۹, and ۱۹۹۲ adolescents were chosen in the ۱st to ۳rd phases. Furthermore, simple random sampling was used for selecting ۹۲۳, ۶۹۴, ۱۰۰۰, and ۲۰۱۵ health professionals and ۸۱۴, ۴۵۲, ۴۲۰, and ۵۰۲ cardiac patients. A multistage sampling method was adopted for the collection of samples from parents of preschoolers and primary school children aged ۲-۱۰ years, adolescents’ parents, and some teachers. A prospective cohort study was started on ۶۵۰۴ eligible individuals.CONCLUSION: The IHHP, as a comprehensive community-based interventional trial in Iran, among the few population-based studies around the world, has reasonable sampling methods and sample size. 

Keywords:

Cardiovascular Disease , Sample Size , Sampling Design , Isfahan Healthy Heart Program