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Table 2 Estimated Changes in Concussion Rates by Time Period and Specific Language of TBI Laws, 2005/06–2017/18

From: Evaluating the effectiveness of traumatic brain injury state laws among high school athletes

Specific Language of TBI Laws

After First Change Point

After Second Change Point

Incidenta

95%CI

Recurrenta

95%CI

Incident vs. Recurrentb

95%CI

Incidenta

95%CI

Recurrenta

95%CI

Incident vs. Recurrentb

95%CI

Overall

1.85%*

1.14, 2.56%

1.12%*

0.00, 2.26%

− 0.61%

− 1.24, 0.03%

− 1.08%*

− 1.43, − 0.72%

− 0.62%

− 1.40, 0.16%

− 0.15%

− 0.48, 0.19%

Specified Category of Healthcare Provider for RTP Clearance

2.03%*

0.86, 3.21%

1.86%*

0.68, 3.06%

0.71%

− 0.23, 1.66%

− 0.78%*

− 1.16, − 0.39%

− 3.29%*

− 5.57, − 0.96%

− 1.84%*

− 3.55, − 0.09%

Did Not Specify Category of Healthcare Provider for RTP Clearance

8.28%*

4.93, 11.75%

5.77%*

0.57, 11.24%

− 2.31%

− 7.46, 3.13%

− 7.35%*

− 10.02, − 4.59%

− 5.54%*

− 10.01, − 0.86%

− 0.41%

− 0.84, 0.03%

Specified Multiple Categories of Healthcare Providers for RTP Clearance

2.77%*

0.90, 4.68%

3.21%*

0.47, 6.02%

2.33%

− 0.20, 4.93%

− 0.41%

− 0.84, 0.02%

− 4.51%

− 9.00, 0.21%

− 1.87%

− 4.52, 0.85%

Specified Physicians Only for RTP Clearance

− 0.91%*

− 1.61, − 0.21%

2.51%*

0.06, 5.03%

2.42%*

0.39, 4.48%

− 3.35%*

− 6.21, − 0.41%

− 4.25%*

− 7.49, − 0.89%

1.47%

− 1.99, 5.05%

Specified Both Coaches and Parents/Guardian Education

1.65%*

0.87, 2.43%

2.59%*

0.26, 4.99%

0.99%

− 0.96, 2.97%

− 1.15%*

− 1.55, − 0.75%

− 2.10%

− 4.16, 0.01%

0.02%

− 0.36, 0.39%

Specified Either Coaches or Parents/Guardian Education

2.21%*

0.96, 3.47%

8.57%*

1.69, 15.92%

4.93%

− 0.22, 10.35%

− 1.04%*

− 1.71, − 0.38%

− 6.20%*

− 11.02, − 1.12%

− 0.54%

− 1.13, 0.05%

  1. Abbreviations: RTP Return to play, TBI Traumatic brain injury, CI Confidence interval
  2. * P < 0.05
  3. a Additional rate of change per standardized month
  4. b Difference in rate of change per standardized month relative to incident concussion rates