INS and colorectal cancer: Several previous studies have examined the association of circulating insulin and/or glucose levels with risk of colorectal cancer (Yamada et al, 1998; Schoen et al, 1999; Nilsen and Vatten, 2001; Trevisan et al, 2001; Palmqvist et al, 2003; Saydah et al, 2003; Jee et al, 2005; Tsushima et al, 2005; Limburg et al, 2006; Gunter et al, 2008; Stocks et al, 2011).