Notably, the risk of cognitive impairment among retired professional soccer players grows larger by position, with those such as forwards and defenders being most at risk.
Repeatedly heading the ball is a risk factor for cognitive impairment and self-reported dementia among retired professional soccer players, a study published in the Journal of the American Medical Association shows.
Investigators conducted a cross-sectional study between August 2020 and December 2021 in living, retired, professional male soccer players older than 45 years of age that examined their current cognitive status and investigated their exposures to heading and other soccer-specific risk factors throughout their careers.
The frequency of heading the ball was classified into 3 bands (0-5, 6-15, and >15 times per typical professional match and per typical training session). Cognitive impairment and heading frequency were determined through a questionnaire sent to the participants, the study authors wrote.
The primary outcome of the study was cognitive function. Covariate risk factors for dementia that were collected in the questionnaire included age, body mass index, smoking, and comorbidities, according to the investigators.
A total of 459 respondents reported heading frequency per match and training out of the 878 total posted questionnaires, according to the investigators. All the participants were male, with a mean (SD) age of 63.68 (10.48) and body mass index (BMI) of 27.22 (2.89).
For respondents who reported heading 0-5 times per match, the prevalence of cognitive impairment was 9.78%. Those reporting 6-15 times had a prevalence of 14.78%, and those reporting heading more than 15 times per match had a prevalence of 15.20% (P = 0.51), the results of the study show.
When compared with the lowest heading frequency per match (0-5), the AOR was 2.71 (95% CI, 0.89-8.25) for players reporting 6 to 15 headings per match and 3.53 (95% CI, 1.13-11.04) for players reporting more than 15 headings per match, according to the study authors.
In considering the frequency of heading per match and training together for each player, the risk of cognitive impairment increased with the cumulative heading frequency. Compared with players who headed 0 to 5 times on both occasions, the AOR was 4.29 (95% CI, 1.14-16.10) for players who headed 6 to 15 times and 4.71 (95% CI, 1.20-18.45) for players who headed more than 15 times on both occasions, the study results indicate.
In looking specifically at various soccer positions, the odds of having cognitive impairment increased in positions that were exposed to heading more often. The lowest prevalence was with goalkeepers (AOR 1, reference), followed by mid-fielders (AOR, 1.48; 95% CI, 0.22-9.76), forwards (AOR, 1.92; 95% CI, 0.32-11.45), and defenders (AOR, 3.16; 95% CI, 0.54-18.62), according to the study.
The investigators concluded that based on these results, exposure to factors associated with playing positions in the outfield contributed to the increased risk. This was supported by the findings that show defenders headed the most, followed by forwards, midfielders, and goalkeepers.
Until recently, many studies that aimed to analyze disease outcomes in soccer players have focused on concussion, though many of these studies focused their analysis on young active players who would be too young to show late cognitive effects, the researchers discussed.
“In active players, heading the ball just 20 times during practice sessions can cause immediate and measurable effects on cognitive ability and function. Therefore, it would seem advisable to reduce exposure to head impacts and repetitive subconcussive head injuries,” the researchers concluded.
Espahbodi S, Hogervorst E, Macnab TP, et al. Heading frequency and risk of cognitive impairment in retired male professional soccer players. JAMA Netw Open. 2023;6(7):e2323822. doi:10.1001/jamanetworkopen.2023.23822