“…In contrast, relatively few studies have investigated the vascular contribution to cognitive impairment in Parkinson's disease (PD), and the results are inconsistent (Slawek et al, 2008;Rektor et al, 2009;Doiron and Simard, 2012;Jones et al, 2014). Indeed, it is still unclear whether the reduced autonomic activity in untreated PD lowers the risk of co-occurring hypertension, diabetes, and hyperlipidemia (Scigliano et al, 2006), or whether those same VRFs could instead be risk factors for PD itself (Simon et al, 2007;Qiu et al, 2011;Zhang and Tian, 2014).…”