These two cohorts were designed to examine the increasing burden of chronic diseases among Korean populations. The studies investigated determinants for stroke, osteoporosis, dementia and cancer among middle-aged and elderly Korean populations. The Namwon Study baseline survey was performed between 2004 and 2007 (n = 10 667), and followed up 4 years later (n = 8157, follow-up rate = 76.5%). The baseline survey of the Dong-gu Study was administered over 2007-2010 (n = 9260), and will be followed up between 2014 and 2015. Questionnaires included assessment of cognitive function, psychiatric health and lifestyle factors. Clinical examinations, biochemical tests and genotyping focused on evaluating the determinants of target diseases and their intermediate phenotypes. Potential collaborators will be invited to contact the chief investigators.