Ken Belson

In perhaps its clearest admission that football can cause degenerative brain disease, the NFL’s top health and safety official admitted Monday that there was a link between the sport and chronic traumatic encephalopathy, a brain disease found in dozens of retired players.

Peyton Manning, one of the most decorated quarterbacks in NFL history, said Monday that he would retire after 18 seasons.

Researchers at several universities and research institutes were awarded almost $16 million Tuesday to find a way to diagnose, while victims are alive, chronic traumatic encephalopathy, a degenerative brain disease linked to repeated head hits in contact sports.