Cerebral concussion is common in collision sports such as professional football, and the effects of recurrent injury have forced several high profile players into early retirement in recent years.
To determine the incidence of previous cerebral concussion in retired professional football players, and to determine any associations between recurrent concussion and chronic neurological decline.
A 2001 general health questionnaire was administered to and completed by 2,488 retired National Football League players (69% return rate).
Analysis of the completed surveys revealed that 61% of the former players sustained at least one concussion during their professional careers, and 24% sustained 3 or more concussions. Additionally, there was a significant relationship (r = 0.64; p < 0.001) between the number of concussions sustained as a professional player and the number sustained as a college player. Although recurrent concussion has been considered a potential predisposition to Alzheimer's Disease, the results of our study did not reveal a significant association between football exposure or concussion history and probable Alzheimer's Disease (p > 0.05). However, results of 263 retired players diagnosed with clinical depression revealed an association between concussion history and depression (X2 = 64.69, df = 3, p < 0.001). Retired players with 5+ previous concussions had nearly a 3-fold risk of incident depression, and those with 3–4 previous concussions had a 2-fold risk of incident depression, compared to those retired players with no history of previous concussion.
Our results suggest a possible link between recurrent sport-related concussion and an increased risk of clinical depression. The findings emphasize the importance of understanding the potential chronic neurological consequences of recurrent concussion.