For Denmark, you probably have consistent medical records, free medical care (adding to consistency), and a homogenous population. Which is worth a lot for tryi

For Denmark, you probably have consistent medical records, free medical care (adding to consistency), and a homogenous population. Which is worth a lot for trying to do a large scale retrospective. Now Denmark is probably not that unique vs Sweden/Norway/whatever, but any country in the region probably is ripe for statistical analysis.