Metting, Esther I
Riemersma, Roland A
Kocks, Janwillem H
Piersma-Wichers, Margriet G
Sanderman, Robbert
van der Molen, Thys
Article History
Received: 3 June 2014
Revised: 26 August 2014
Accepted: 5 October 2014
First Online: 8 January 2015
Competing interests
: RAR is a member of the advisory board of Certe Laboratories. MGP-W is the director of Certe Laboratories. TvdM is a member of the board of trustees of Certe Laboratories. JWHK is an Associate editor of <i>npj Primary Care Respiratory Medicine</i>, but was not involved in the editorial review of, nor the decision to publish, this article. The other authors declare no conflict of interest.