Field position and subjective number of headers are associated with subcortical volumes in female soccer players

BACKGROUND AND PURPOSE: Repetitive head impacts (RHI) from soccer headers could be linked to neurodegeneration, but their effects on young, active athletes are still under debate. This exploratory, cross-sectional study aimed to generate hypotheses about the relationship between soccer headers, brain volume alterations, and neuropsychological function in female soccer players. The analysis focused on brain regions previously identified as vulnerable to RHI. METHODS: 19 semi-professional female soccer players (mean age: 22.4±4.1 years) and 15 non-contact-sport controls underwent structural MRI. Players were assessed for neuropsychological function and measures of exposure (field position, subjective number of headers, age at first exposure, and total years played). Subcortical grey and corpus callosum white matter volumes were calculated using FreeSurfer for all participants. Group differences in brain volumes were assessed. Among players, associations between brain volumes, exposure measures, and neuropsychological function were analyzed, controlling for multiple comparisons using a 25% false discovery rate. RESULTS: =0.001). No statistically significant associations were found for other exposure measures, brain volumes, or any of the neuropsychological outcomes. CONCLUSION: A higher subjective number of headers among female soccer players was associated with group-level findings regarding reduced subcortical grey and central white matter brain volumes in our small sample of female soccer players. While these findings are exploratory, group-level, and of uncertain clinical significance, they provide hypotheses for future studies and suggest directions for further investigation.