“…Baseline characteristics of 20 studies[ 13 – 32 ] included are listed in Table 1 . 8 of those are prospective cohort studies[ 13 , 14 , 18 , 21 , 23 , 24 , 26 , 32 ], others are retrospective cohort studies. The studies were conducted in the following countries: the United States, Israel, China, Indian, Korea, Poland, Czech, Denmark, Japan, Turkey, Italy and Germany.…”