“…The robustness of the result was tested by excluding these 4 studies, and no obvious change happened. Third, of all the studies, 14 [5,14,21,22,24,25,27,28,31,32,36,37,40,42] were performed in Europe, 6 [23,26,29,30,34,39] in North America, 4 [33,35,38,41] in Asia, and 1 [20] in Africa, reflecting a limitation of the evidence generalization. Lastly, all the documents were in English, meaning the possibility of language bias.…”