“…Most studies were conducted in Germany [22,27,29–31,34–37,40,42], followed by studies that were performed in the USA [18,20,25,28,32,41], in Australia [23,24,26,33,38], in the UK [19,39] and in Sweden [21]. The target populations were mainly school age children [18,21,22,28,34,35,37,41], pre-school aged children [20,25,33] and other specific populations [19,23,24,27–33,36,39,40,42]. Investigated strategies included preventive intervention [25,26,32,33,41,42], screening strategy [35,36], and invasive/non-invasive treatment [18–24,27–31,34,37,40].…”