9.6 The influence of age of first exposure to American football on concussion history and age of first concussion in NCAA football players

Objective To examine the association between estimated age of first exposure to American football (AFE) and concussion history in National Collegiate Athletic Association (NCAA) football players Design Cross-sectional, observational study Setting Participants were recruited from 30 colleges/universities as part of the NCAA-U.S. Department of Defense Grand Alliance: Concussion Assessment, Research and Education (CARE) Consortium. Participants There were 2341 freshmen football players (age=18±1 years) included in analyses, including 690 (29%) with a previous history of concussion. Assessment of Risk Factors AFE (mean±standard deviation: 9±3 years; range: 3–17 years; AFE<12 years, n=1881 [80%]) Outcome Measures Concussion history (i.e., yes vs. no; number of pre-collegiate concussions [0, n=1651(71%); 1, n=545(23%); 2, n=111(5%); 3, n=28(1%), 4+, n=6(1%)]; age of first concussion [AFC; mean±standard deviation, 15±3 years; range, 3–20 years]) Main Results AFE was not associated with concussion history (yes vs. no) whether analyzed continuously (p=0.341, odds ratio(OR)=0.99 [95% confidence interval(CI), 0.96–1.02]) or dichotomously at age 12 (p=0.076, OR [AFE<12 vs. AFE>12]=1.23 [95%CI, 0.98–1.55]). AFE was not associated with number of pre-collegiate concussions when analyzed continuously (p=0.140, incidence rate ratios(IRR)=0.98 [95%CI, 0.96–1.01]), but football players with AFE<12 had slightly greater risk of sustaining more concussions (p=0.010, AFE<12 IRR=1.13 [95%CI=1.03–1.23]. Younger AFE was associated with younger AFC when analyzed continuously (p=0.010, R2=0.010) and dichotomously at age 12 (p=0.030, AFE<12 Parameter Estimate=-0.28 [95%CI, -0.54 to -0.03]). Conclusions Younger AFE does not increase likelihood of sustaining a concussion by college; however, it may be associated with younger AFC. Future work should examine the effects of younger AFC on clinical outcomes. This abstract has been published in full manuscript format and has the following citation: BMJ Citation https://www.tandfonline.com/doi/full/10.1080/15438627.2021.1966008