Table 4.
Interaction of Sport and Time Modeling Longitudinal Whole Hippocampus and Subfield Volumes between Football Athletes (n = 36) and Volleyball Athletes (n = 23), All without In-Study Concussion
| Interaction coefficient (volume difference in mm3 per year between sports) (CI) | T (p value) | R2 | |
|---|---|---|---|
| Hippocampus | –79.26 (−181.31, 22.78) | –1.52 (0.128) | 0.50 |
| Dentate gyrus | 3.43 (−18.90, 25.76) | 0.30 (0.763) | 0.35 |
| CA1 | –35.22 (−59.67, −10.77) | –2.82 (0.005)a | 0.42 |
| Subiculum | –5.15 (−18.57, 8.27) | –0.75 (0.452) | 0.34 |
| ERC/PRC | –42.92 (−112.42, 26.57) | –1.21 (0.226) | 0.49 |
The interaction coefficient reflects the difference between sports in the per-year change in volume (i.e., the difference in slopes in Fig. 5A, equivalent to the differences in volume change per year by sport in Fig. 5B). A negative interaction coefficient means decreasing volumes in football compared to volleyball over time (all players without concussion during the study), using age at the time of baseline scanning and total intracranial volume as covariates.
Bold text indicates the statistic meets multiple comparison correction across subfields by false discovery rate.
CA1, cornu ammonis area 1; ERC/PRC, entorhinal cortex/perirhinal cortex; CI, confidence interval.