“…Of these, 7 were omitted (3 were not accessible through the internet network of the university library of Karolinska Institutet and no contact information was available to contact the first authors in order to receive reprints of the papers [4,5,6]; four other studies used the material of an already published RCT [7,8,9,10]). As a result, 42 [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52] papers remained for inclusion in this study.…”