MTNR1B and delirium: In this matched exploratory case–control study of 94 participants who underwent elective orthopedic surgery, of whom 47 developed incident postoperative delirium and 47 did not develop delirium, individuals without delirium had an increased adjusted odds of having the KIBRA rs17070145 CT/TT and MTNR1B rs10830963 CG/GG genotypes.