In all six countries, data collection took place twice with about 12-18 months between baseline and the follow-up measurement. Data collection started from November 2010 to March 2011 in all countries, and ended between September and November 2011. In 2015/2016, a 5-year EPOSA follow-up measurement took place in the Netherlands. In this follow-up measurement, clinical knee and hip osteoarthritis was assessed in approximately 350 Dutch EPOSA respondents. In addition to all questions that have been asked in the context of the Longitudinal Aging Study Amsterdam (e.g., questions on health care use and physical, emotional, social, and cognitive functioning), additional questions have been asked to these respondents about pain and functional limitations.
For an overview of the data collected at baseline and at 12-18 months follow-up, we refer to the codebooks at baseline and follow-up. Data from the EPOSA database are available for use for specific research questions (see Data Requests).