Funding for this research was provided by:
Eesti Teadusagentuur (Mobilitas Pluss Returning Researcher Grant (MOBTP91))
Estonian Headache Society
Received: 25 March 2020
Accepted: 29 May 2020
First Online: 1 June 2020
Ethics approval and consent to participate
: The study was approved by the Research Ethics Committee of Tartu University (permission no. 252 T-15). All the subjects were informed of the purpose of the study and all the respondents gave their digital informed consent for participation.
: Not applicable.
: The authors declare that they have no competing interests.