WEDNESDAY, March 13 (HealthDay News) -- Young men with low incomes and poor mental skills are at significantly increased risk for mild traumatic brain injuries, according to a new long-term study.
Researchers examined data from more than 300,000 young men who were conscripted for military service in Sweden between 1989 and 1994, and underwent testing of their mental skills. They were followed for an average of 19 years.
Of the participants, more than 4,700 had suffered one mild traumatic brain injury before being tested on their mental skills, while more than 11,000 of them sustained one such injury and nearly 800 had at least two mild traumatic brain injuries during the study period.
Falling, assault and traffic crashes were the most common causes of mild traumatic brain injury, according to the study published online March 12 in the BMJ.
Mental ability was 5.6 percent lower in participants who sustained a mild traumatic brain injury in the two years before mental-skill testing. And compared to those who did not suffer any such injury, it was 15 percent lower in those who suffered at least two mild traumatic brain injuries after mental-skill testing, according to a journal news release.
Besides low overall mental function, other risk factors for mild traumatic brain injury were low total income, a high level of physical fitness, hospital admission for intoxication, a previous such brain injury, low education level and taking early disability pension, said researcher Anna Nordstrom and colleagues from Umea University, in Sweden.
The investigators concluded that limited mental ability and factors related to low social and economic status are important risk factors for mild traumatic brain injuries, and that "successful prevention of mild traumatic brain injuries may include an assessment and evaluation of these risk factors."
About 10 million traumatic brain injuries occur worldwide each year, and mild traumatic brain injuries account for 70 percent to 90 percent of these cases. Rates are highest among young males, according to the study.
Current research suggests that mild traumatic brain injury causes changes in brain tissue and has important long-term effects on thinking skills, including attention, memory, learning and brain processing speed. These types of problems may occur in 15 percent to 25 percent of people who suffer a mild traumatic brain injury.
While the study tied low mental ability with greater brain injury risk, it did not prove a cause-and-effect relationship. An accompanying journal editorial noted that additional research is needed to support the new findings.
The U.S. National Institute of Neurological Disorders and Stroke has more about traumatic brain injury.
-- Robert Preidt
SOURCE: BMJ, news release, March 12, 2013
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