The European Journal of Public Health, Vol. 28, No. 1, 145–149 The Author 2017. Published by Oxford University Press on behalf of the European Public Health Association. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com doi:10.1093/eurpub/ckx122 Advance Access published on 31 August 2017