“…Besides, seven studies defined the elderly with a chronological age of 55 and above, such as studies by [ 26 , 10 , 6 , 15 , 27 , 28 ]. Eleven studies targeted at elderly aged 60 and above, including studies by [ 12 , 29 , 30 , 31 , 32 , 33 , 18 , 8 , 19 , 19 , 20 , 11 ]. Out of 26 studies, only two studies [ 30 , 34 ], compare the elderly population with the younger generation in their studies.…”