Reacción a "Reactions: study suggests elite footballers more likely to develop dementia "

This is an epidemiological study of a large number of cases and controls, with quality methodology in this context. Clinical diagnoses were obtained from codes from death certificates, hospital diagnostic codes and use of specific medication that were available from different dates, so there is not a complete coverage of the whole period. Diagnostic coding has its limitations, especially in older data, as it is not detailed. Death certificates may omit the diagnosis of neurodegenerative disease "as a cause of death" on some occasions, especially in older registries where the impact of these diseases as a cause of death was minimised. It is not specified whether primary care data have been included. This could in any case minimise the frequency of neurodegenerative diseases, albeit similarly in cases and controls. On the other hand, a study based on diagnostic codes does not allow clinical details to be obtained in the same way as a review of medical records, but because of the ambition of the project at the numerical level it would have been very difficult to obtain.  

This study is in line with others published in professional footballers that show an increase in overall neurodegenerative diseases, even though they usually have a lower level of cardiovascular risk factors - in this study cardiovascular mortality was similar, that attributable to smoking was lower. The risk of some of the diseases is somewhat lower and there is no increased risk of Parkinson's disease or ALS. These differences could have different reasons, including some discussed by the authors themselves, that because professionalisation in Swedish football was later than in other countries, exposure to trauma may have been less intense or prolonged.  

In terms of practical implications, both the United States and the United Kingdom have taken steps to minimise head injuries in children by limiting the use of overhead kicks or modifying the type of ball. However, it is unclear whether the damage from repeated head injuries comes from head kicks or whether it is the higher intensity unintentional impacts - such as being hit by a ball or collisions between players that sometimes result in concussions - that are the main cause of the damage, Therefore, the need to use other preventive measures -such as the use of helmets-, to establish strict "punitive" protocols for aggressive play that could lead to this type of trauma or to withdraw from the game, rest and monitoring of players who have suffered a concussion, is under discussion.  
The progressive professionalisation of football from an increasingly younger age and the possible increased aggressiveness on the pitch do not suggest that the risk has been significantly reduced so far.