A flowchart of included studies is shown in Fig. 1. The initial search yielded 1,635 articles; from which 224 duplicates were removed. A further 1,180 articles were excluded in the title and abstract screening with an additional 153 excluded after the full text screening. A final 78 studies were deemed to meet the inclusion criteria.

Flowchart of included studies

The included studies originated from 17 different countries: China (n = 41) [4, 11, 30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68], Japan (n = 6) [16, 44, 69,70,71,72], Germany (n = 4) [13, 73,74,75], Romania (n = 3) [8, 76, 77], South Korea (n = 3) [78,79,80], Spain (n = 3) [22, 81, 82], United States (n = 3) [83,84,85], Italy (n = 3) [20, 21, 86], India (n = 2) [5, 87], Malaysia (n = 2) [3, 88], New Zealand (n = 2) [35, 62], Australia (n = 2) [89, 90], Belgium (n = 2) [18, 91], United Kingdom (n = 2) [92, 93], Canada (n = 1) [94], Iran (n = 1) [9], Russia (n = 1) [47], Slovenia (n = 1) [95], and Sweden (n = 1) [75]. Several study designs were utilised in the literature, these included: 51 comparisons of mean differences between groups [3, 5, 8, 9, 22, 30,31,32,33,34,35, 38,39,40,41, 43,44,45, 47,48,49,50, 52,53,54,55,56,57,58,59,60,61,62, 66, 68, 70, 72, 75,76,77,78, 80, 83, 85,86,87,88,89, 93,94,95], 20 cluster/principal component analyses [5, 11, 13, 16, 18, 31, 32, 38, 42, 51, 58, 63, 64, 68, 73, 79, 82, 85, 87, 90], 14 reliability studies [20,21,