Funding for this research was provided by:
The Finnish Work Environment Fund (114095)
The Finnish Institute of Occupational Health
Received: 7 May 2018
Accepted: 27 January 2020
First Online: 3 February 2020
Ethics approval and consent to participate
: The Ethical Committee for Epidemiology and Public Health of the hospital district of Helsinki and Uusimaa in Finland approved the study. All the participants signed their written informed consent for participating the study and publishing the results.
: Not applicable.
: The authors declare that they have no competing interests.