Epidemiology is a unique science that identifies the incidence and distribution of diseases and their risk factors. An example of response to this need is the "Prospective Epidemiological Study of Urban and Rural Populations" (PURE), conducted in 27 countries around the world, including Poland, which is a unique multi-year cohort study of more than 150,000 people. The purpose of the PURE study is a prospective, multilevel observation of the development of chronic non-communicable diseases and their risk factors. The Polish cohort includes 2036 people from urban and rural areas with a rate response of 88.2% over 15 years. The main research focus of the analyses of the data collected in the Polish PURE cohort during the multiyear follow-up period was on the incidence and determinants of chronic non-communicable diseases. The results of the PURE study help in understanding the development of cardiovascular diseases and provide a unique opportunity for research and respond to the need to create guidelines, recommendations, and health policies in line with evidence-based medicine. Its results are compelling evidence pointing to the need to continue to create, develop, and maintain regional and global observational cohorts over many years.