Dementia risk heterogeneity across cognitive decline stages and age-defined cohorts of former professional association footballers

Abstract Former professional footballers have an elevated neurodegenerative disease development and mortality risk, relative to control populations. Whether this risk is uniform across cognitive decline stages, and through age-defined cohorts, remains unclear. This study investigated whether this risk was heterogeneous across both dimensions through a secondary analysis of a cross-sectional cohort of former professional footballers. Findings were contextualised with a detailed football technology timeline for the cohort. The null hypothesis was that footballers would demonstrate a consistent, unvarying elevated neurocognitive decline risk relative to matched control populations, across cognitive decline stages and age-defined subgroups. Hopkins Verbal Learning Test scores (HVLT, as a validated dementia screening tool), stratified for participants’ ages, were utilised to develop cumulative event curves, and age and education adjusted binary logistic regression models, to assess cohort differences in dementia risk, at different stages. Footballers’ relative dementia risk varied depending on the HVLT cut-off scores. Age-based stratification further revealed heterogeneity across cohorts, that did not follow any discernible pattern. Together, these findings did not support the null hypothesis and suggest the dementia risk landscape in professional footballers is more complex than a single population-level estimate implies. Poor cognitive performance in footballers extended beyond those exclusively exposed to highly hydrophilic laced uncoated leather balls, suggesting that dementia risk in footballers is not only an historic issue.