Objectives:A prior report revealed an average of 7.2 (0.67 per 100,000 participants) traumatic brain injuries (TBI) per year in high school (HS) and college football players from 1989 through 2002. Our goal is to update the profile of TBI in HS and college football players and evaluate the efficacy of state laws implemented to reduce brain injuries.Methods:We retrospectively reviewed 17 academic years (July 2002 through June 2019) of TBIs catalogued by the National Registry of Catastrophic Sports Injuries (NRCSI). Descriptive statistics were collected using Excel and SPSS. The incidence of TBI was compared with the prior 13-year period. In addition, the incidence of TBI was assessed at the HS level during the pre (2002-2009[BB3] [BI([4] [BI([5] ), transitional (2009-2014), and post (2014-2019) universal adoption time periods of the Lystedt laws. Multinomial logistic regression analyses were performed to determine the odds of TBI based on level of play, Lystedt law adoption eras, and position played.Results:During the study period, there was a total of 177 TBIs (10.4 per year, 0.82 per 100,000 participants): 164 (92.7%, 0.81 per 100,000, 9.65 per year) in HS athletes and 13 (6.6%, 0.96 per 100,000, 0.76 per year) in college athletes. The risk of TBI at the HS level was significantly higher than at the college level (1.99: 95% CI, 1.137-3.517, P<0.0001). Compared to the prior 13-year period, the risk of TBI during the study period was 1.29 (95% CI, 1.004-1.656, P=0.047) with a greater increase at the college (4.40: 95% CI, 0.993-19.5, P=0.051) than the HS level (1.22: 95% CI, 0.946-1.577, P=0.124). There were 51 fatalities (3 per year, 0.24 per 100,000 participants) with a risk of 1.63 (95% CI: 0.65-4.11, P = 0.3) at the college (n=5, 0.29 per year, 0.36/100,000) compared with the HS (n=46, 2.71 per year, 0.22 per 100,000) levels. The risk of a fatality in the current study compared with the prior study was 4.32 (95% CI: 2.05-9.09, P= 0.0001) with higher risks at both the HS (5.17, 95% CI: 2.21-12.1, P =0.0002) and college (1.8, 95% CI: 0.35-9.3, P = 0.48) levels. The incidence of TBI in HS increased significantly from the pre (0.57 per 100,000) to the transitional (0.78 per 100,000, OR = 4.7, P<0.001), and from the transitional to the post universal adoption (1.17 per 100,000, OR = 13.7, P<0.0001) eras of the Lystedt law. The most common positions among HS and college athletes suffering TBI were linebacker (26, 22.6%) and running back (20, 17.4%), and defensive back (16, 13.9%).Conclusions:The incidence of TBI has increased 29% during the 2002-2019 period compared to the prior 13-year period with a 440% and 22% rise in college and HS cases, respectively. The risk of fatality increased 432% compared to the prior 13-year period with an increase of 517% and 180% at the HS and college levels, respectively. The increased incidence of TBI at the HS level has occurred despite implementation of the Lystedt laws. Further research is necessary to determine the risk factors for TBI in order to develop prevention strategies.Figure 3B.Incidence Rates During Lystedt Law Adoption Eras