AGT and idiopathic pulmonary fibrosis: The results showed that ACE I/D gene polymorphism was correlated with the risk of IPF in the genetic models of D versus I, DD versus II and DD versus II + ID in Chinese Han population, and the effect values were (OR = 0.53, 95% CI [0.42, 0.67], P < .00001), (OR = 0.37, 95% CI [0.24, 0.57], P < .00001) and (OR = 0.30, 95% CI [0.21, 0.43], P < .00001), moreover, the Ang II level of IPF patients was higher than that of control group (MD = 14.29, 95% CI [11.20,17.37], P < .00001).