From 2011-2015 the HELIUS study included almost 25.000 individuals aged 18 to 70 years. Participants were examined by interviews, questionnaire and physical examination. Based on the first measurements a lot of questions could be answered. You can find a (Dutch) summary here:

From 2019-2021 all the participants of the HELIUS study will be invited to participate again. This makes it possible to investigate how health, health care and well-being develop over time.