There is currently no evidence showing that heading a football has a negative impact on long-term cognitive function and brain health.
The possible long terms effects of playing sport on the brain are again in the media. Some of this has been driven by the recent publication of a study that has examined the brains of former American Football players.1 This study has found that most of these brains have evidence of chronic traumatic encephalopathy (CTE). Almost all of the brains from retired NFL players (111/112 players) were affected.
One of the main issues with this study is selection bias – the brains were all donated by players who had developed cognitive issues and were concerned that they had CTE. It is the authors belief that the damage is related to accumulated trauma from repeated blows to the head – and not just the cumulative effects of concussion. It is not clear whether the findings would have been different had it been possible to select a random sample of subjects. While the study is clearly thought-provoking it is unclear about what significance this has in football.
In football it has been suggested that heading the ball might be associated with longer-term cognitive dysfunction. This is currently speculation only with no evidence to demonstrate this relationship. This is highlighted by the recent publication of a systematic review and meta-analysis which examined the effects of football heading on the brain.2 A total of 467 unique studies were identified (with only 28 studies meeting the selection criteria). The meta-analysis included a total of 2288 participants (933 female participants and 1355 male participants) aged 13–70 years. This analysis found no association.
Clearly there is still much to learn about the longer-term implications of sport-related concussion and head injuries on the brain. At present however there is no evidence to suggest that heading the ball is unsafe.
1 Mez J, Daneshvar DH, Kiernan PT et al. Clinicopathological Evaluation of Chronic Traumatic Encephalopathy in Players of American Football. JAMA. 2017;318(4):360-370
2 Kontos AP, Braithwaite R, Chrisman SPD et al. Systematic review and meta-analysis of the effects of football heading. Br J Sports Med 2017;51:1118-1124.