Adult cognitive ability and educational level in relation to concussions in childhood and adolescence: a population study of young men.

Objective: To investigate the relationship of concussion(s) suffered through childhood and adolescence with completed level of school education and cognitive ability in young adulthood. Methods: Educational level and scores on a test of cognitive ability were obtained for a cohort of 130 298 young men processed by the Danish draft board. Of these, 6146 had, at some age from birth onwards, been briefly admitted to hospital with a main discharge diagnosis of concussion. A further 402 had two such concussions and 48 had three or more. Results: Educational level and cognitive ability test scores were negatively associated with the number of concussions and the age at concussion(s). Most markedly, compared to the 123 684 non-concussed men, those with two or more concussions had lower educational levels (OR = 0.48; 95% CI = 0.26-0.89), as also did those sustaining one concussion between the age of 13 up to the time of testing (OR = 0.47: 0.42-0.52). Conclusions: Since concussions do not generally have long-term effects, the results suggest that lower educational level is primarily a risk factor for sustaining a concussion at all ages, but in particular in adolescence more than in childhood and in the case of multiple concussions. It should, however, be recognized that, in some proportion of cases, the educational deficits have probably arisen as a consequence of the persistent symptoms of a lengthy post-concussional syndrome.