کاردیوواسکولر

Cardiovascular disorders are responsible of nearly fifty percent of deaths in industrial and developing countries. However numerous studies have revealed considerable differences in distribution of cardiovascular risk factors at the national, regional and ethnic levels. There is a necessity to elucidate the status of all recognized risk factors in any population to attribute these differences in the incidence of cardiovascular events to the changes in some risk factors or natural history of the disease in that society. The study of cardiovascular risk factors in the 17th zone of Tehran is performed according to the model of MONICA project of WHO. In this project the trend of cardiovascular events and their association with changes in risk factors is monitored in more than twenty countries and 35 centers. In this article we describe some aspects of the statistical design and sampling procedure of our aformentioned study such as sampling framework, sampling methods and its rationale, best size of clusters, sample size and sample selection in each cluster.