“…In the control group, 236 were rapid, 529 were intermediate, and 917 were slow. The study locations included three studies performed in United States (Li et al, 2006;Jiao et al, 2007;Suzuki et al, 2008), one in Turkey (Ayaz et al, 2008), and two multi-center studies (Bartsch et al, 1998;Li et al, 2002). Regarding the division of NAT2 phenotypes, three studies utilized three phenotypes (rapid, intermediate, and slow) (Li et al, 2006;Jiao et al, 2007;Suzuki et al, 2008) and other three studies divided the phenotypes into two categories (rapid and slow) (Bartsch et al, 1998;Li et al, 2002;Ayaz et al, 2008).…”