Research Reports - Cognitive function and other risk factors for mild traumatic brain injury in young men
BMJ. 2013 Mar 11;346:f723
Nordström A, Edin BB, Lindström S, Nordström P
OBJECTIVE: To investigate cognitive function and other risk factors for mild
traumatic brain injury in young men.
DESIGN: Nationwide prospective cohort study.
PARTICIPANTS: 305 885 men conscripted for military service from 1989 to 1994.
MAIN OUTCOME MEASURE: mild traumatic brain injuries in relation to cognitive
function and other potential risk factors assessed at conscription and follow-up.
RESULTS: Men with one mild traumatic brain injury within two years before
(n=1988) or after cognitive testing (n=2214) had about 5.5% lower overall
cognitive function scores than did men with no mild traumatic brain injury during
follow up (P<0.001 for both). Moreover, men with at least two mild traumatic
brain injuries after cognitive testing (n=795) had 15% lower overall cognitive
function scores compared with those with no such injury (P<0.001). Independent
strong risk factors (P<1×10) for at least one mild traumatic brain injury after
cognitive testing (n=12 494 events) included low overall cognitive function, a
previous mild traumatic brain injury, hospital admission for intoxications, and
low education and socioeconomic status. In a sub-cohort of twin pairs in which
one twin had a mild traumatic brain injury before cognitive testing (n=63), both
twins had lower logical performance and technical performance compared with men
in the total cohort with no mild traumatic brain injury (P<0.05 for all).
CONCLUSION: Low cognitive function, intoxications, and factors related to low
socioeconomic status were strong independent risk factors for mild traumatic
brain injuries in men. The low cognitive function in twin pairs discordant for
mild traumatic brain injury suggests a genetic component to the low cognitive
function associated with such injuries. The study included only men, so
inferences to women should be made with caution.