“…Studies were published during 2013 to 2020, and the sample size of the included publications varied between 22 and 533256 subjects. Among the included studies, there were 8 high quality studies reporting the adjusted risk estimate for T2D associated with DII as the primary outcome [ 32 , 33 , 39 , 50 – 52 , 59 , 63 ], while for other studies [ 23 – 31 , 34 – 38 , 40 – 49 , 53 – 58 , 60 – 62 , 64 – 70 ], T2D was a secondary outcome and the crude odds ratio for T2D was calculated based on the frequency of subjects with T2D in the highest category of DII, compared with subjects in the lowest category. DII was calculated with the use of 7-day dietary record in 3 studies [ 31 , 44 , 50 ], 24-hour dietary recall in 11 studies [ 35 , 37 , 46 , 51 , 54 , 55 , 62 – 64 , 68 , 70 ], dietary history questionnaire in 2 studies [ 45 , 52 ], and food frequency questionnaire (FFQ) in the remaining studies.…”