Text and Data Mining valid from 2016-07-21
Received: 12 August 2015
Revised: 25 March 2016
Accepted: 27 April 2016
First Online: 21 July 2016
: IT, NC and JK are associate editors of npj Primary Care Respiratory Medicine, but were not involved in the editorial review of, nor the decision to publish this article. The other authors declare no conflict of interest.