- Correspondence to Johanna Pekkala, Department of Public Health, University of Helsinki, Helsinki 00014, Finland;
- Received 2 June 2017
- Revised 22 December 2017
- Accepted 16 January 2018
- Published online 30 January 2018.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.