1 1 Manchester Urban Collaboration on Health, Centre for Epidemiology, Institute for Population Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK.
2 2 Municipal Health Service Utrecht, Utrecht, Netherlands.
3 3 Department of Public Health and Policy, University of Liverpool, Liverpool, Merseyside, UK.
4 4 Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.