PDE5A and Alzheimer disease: There was a similar association in risk reduction of AD in patients on PDE5 inhibitors compared to non-use (RR: 0.55, 95% CI: 0.38-0.80, p=0.002).<h4>Conclusions</h4>Our meta-analysis showed that the use of Sildenafil is associated with a reduced risk of developing AD by two-fold.