FMO5 and type 2 diabetes mellitus: We retrieved the full text for the remaining 25 articles for further evaluation using the inclusion criteria, and a total of 11 publications were found eligible for this meta-analysis (Doi et al. 2005; Hayaishi-Okano et al. 2003; Jin et al., 2011; Letonja et al. 2012; Lim et al. 2006; Liu et al., 2006; Matsunaga-Irie et al. 2004; Narne et al. 2014; Santos et al., 2005; Yan, 2005; Yang et al., 2006), including 7 with outcomes for T2DM, 7 with outcomes for DN, and 3 with outcomes for CA resulting from a search on the NAD(P)H oxidase p22 phox gene C242T polymorphism (Fig. 1).