Cocoros NM, Svensson E, Szépligeti SK, et al. - An increased long-term risk of developing Parkinson disease may be conferred by influenza infection.

• Using data from the Danish National Patient Registry, a total of 10,271 patients with Parkinson disease and 51,355 controls were included in this case-control study.

• Influenza was found to be related to diagnoses of Parkinson disease more than 10 years post-infection (odds ratio, 1.73).

• Other infections were related to Parkinson disease diagnoses soon following infection, but there were null links after more than 10 years indicating these shorter-term associations are not causal.