Collaborations on data from the Betula-project will be available for external researchers as far as the proposed projects are assessed by the Steering Committee as scientifically sound, and the issues to be studied is not already highlighted in ongoing Betula studies.
Ethical approval should be secured for all new sub studies from the Swedish Ethical Review Authority. This responsibility lies with the individual researcher. DTA/MTA can be assessed by the Betula steering committee before an application is sent to the ERA, but no data will be shared before a copy of the ethical approval has been handed in to the Betula steering committee.
A description of the data available in the betula databse can be found here: https://www.maelstrom-research.org/study/betula (observe that not all data connected to Betula is listed in this description. Questions regarding this should be sent to the contact person for Betula).