TABLE 2.
Historical Cohort Study of Football Players and Non–Football Players vs General Population and Risk of Neurodegenerative Diseases
| Football players (N=438) | Band/glee club/choir members (N=140) | P valuea | |
|---|---|---|---|
| Dementia | |||
| Observed | 13 | 2 | |
| Expectedb | 18.1 | 4.3 | |
| SIR vs expectedc | 0.72 (0.38-1.23) | 0.47 (0.05-1.68) | |
| Years after indexd | 55.3 (51.5, 59.4) | 57.8 (57.2, 58.5) | .44 |
| Age at outcomed | 72.4 (69.3, 77.0) | 76.0 (75.0, 77.0) | .35 |
| Parkinson disease | |||
| Observed | 10 | 5 | |
| Expectedb | 4.2 | 1.0 | |
| SIR vs expectedc | 2.36 (1.13-4.34) | 4.94 (1.61-11.51) | |
| Years after indexd | 52.4 (42.4, 59.6) | 49.8 (37.4, 60.2) | .95 |
| Age at outcomed | 70.5 (58.9, 77.4) | 67.7 (55.5, 78.1) | .95 |
| Amyotrophic lateral sclerosis | |||
| Observed | 2 | 1 | |
| Expectedb | 0.64 | 0.16 | |
| SIR vs expectedc | 3.15 (0.38-11.33) | 6.44 (0.16-35.7) | |
| Years after indexd | 47.6 (46.3, 48.8) | 42.8 (42.8, 42.8) | .67 |
a
P values are for the Wilcoxon rank sum test.
b
Expected numbers of cases are calculated from age-specific person-years and previously published incidence rates in the Olmsted County population.
c
Standardized incidence ratios (SIRs) are calculated on the basis of observed number of cases and expected number of cases. Values are SIR (95% confidence interval).
d
Values are median (25th percentile, 75th percentile).