- Correspondence to Emelie Thern, Child and Adolescent Public Health Epidemiology Unit, Department of Public Health Sciences, Karolinska Institutet, Tomtebodavägen 18A, Widerströmska huset, Stockholm 171 77, Sweden;
- Received 29 June 2016
- Revised 23 November 2016
- Accepted 29 December 2016
- Published online 13 January 2017.
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.