Demographic and Football-Related Characteristics Associated with Objective Cognitive Performance in Former NFL Players with a Normative Sample Comparison: An NFL-LONG Study

BACKGROUND: Risk for neurocognitive disorder is a growing concern for contact sport athletes owing to reports associating head impact exposure (HIE) metrics and cognitive function. OBJECTIVE: To (1) examine the associations and relative importance between objective cognitive performance, demographics, and HIE metrics of former National Football League (NFL) players and (2) compare cognitive performance between former NFL players and matched samples. METHODS: Cross-sectional analysis of former NFL players (n = 295, age: 54.1 ± 14.8 years) using a remote neurocognitive assessment platform (TestMyBrain) collected between March 2022 and October 2022. Players were 1:1 propensity score matched to general population normative male samples on age, race, and highest education level. Cognitive subtests included digit symbol matching (DSM), gradual onset continuous performance test (Grad CPT), trail making test parts A and B (Trails-A -B), paired associates memory for verbal (Verbal PA), paired associates memory for visual (Visual PA), and vocabulary. The HIE metrics examined were age of first exposure to football (AFE), lifetime exposure to football, professional career duration, and lifetime concussion history. Multivariable linear regressions with dominance analysis examined associations and relative importance of demographic data and HIE metrics on cognitive performance; independent t-tests examined group differences across cognitive subtests using mean differences (MDs) and 95% confidence intervals (95%CIs). RESULTS: Age, race, and highest education demonstrated complete dominance over all HIE metrics across the seven cognitive subtests among former NFL players. Professional football career duration demonstrated overall general to complete dominance over the majority of HIE metrics across cognitive subtests, such that greater career duration was associated with lower cognitive performance, while AFE was often dominated by other HIE metrics. Compared to the normative sample, former NFL players had significantly lower DSM (MD: - 3.45, 95% CI - 5.97, - 0.92), Grad CPT (MD: - 14.62, 95% CI - 16.61, - 12.64), Verbal PA (MD: - 5.04, 95% CI - 5.90, - 4.18), Visual PA (MD: - 1.18, 95% CI - 1.90, - 0.46), and vocabulary performance (MD: - 3.84, 95% CI - 5.45, - 2.24), while Trails A and B were not statistically different (p ≥ 0.06). CONCLUSIONS: Demographic factors were completely dominant over HIE metrics for cognitive performance. Among only HIE metrics, professional football career duration superseded lifetime concussion history and AFE. Worse cognitive performance was observed among former NFL players compared with a matched normative sample with varying effect sizes.