Although a study reported that 40 mg/day simvastatin decreased the phospho-tau level in patients with dyslipidemia without dementia (Riekse et al., 2006), other studies reported that statins including 20–80 mg/day simvastatin failed to show a decrease of phospho-tau or total tau level in the cerebrospinal fluid (CSF) in AD patients (Sjogren et al., 2003; Hoglund et al., 2005b; Serrano-Pozo et al., 2010) and middle-aged adults with risk of AD (Carlsson et al., 2008). This evidence concerns the gene MAPT and dementia.