SAINT PAUL, Minn. - A state-mandated study of high school athletes' concussions was unveiled Thursday at the State Department of Health. The Legislature required the study in a 2011 bill.
The study said that athletic trainers from 36 Twin Cities Metro public high schools voluntarily reported 730 concussions. Researchers projected from that an estimated 3,000 concussions among the young athletes in the 2013-2014 school year.
"Football, which is the most heavily participated activity, accounted for 42% of the concussions in the Twin Cities," said Dr. Ed Ehlinger, Minnesota Commissioner of Health. "However, girls and boys hockey had similar rates of concussion (to football). In sports played by both boys and girls in Minnesota, the rate of concussion among girls is higher than among boys, which mirrors national data on that subject."
However, Minnesota fared better than national studies on the outcomes of reported concussions.
"Our study found 5% of reported concussion cases had symptoms lasting longer than two weeks," said Ehlinger. "This result indicates less harm from concussions than the national studies."
Nationally, the rate of cases with such lasting symptoms was 10-15%.
It is not known why girls would have a higher concussion rate than boys, according to study authors.
"There is some speculation about muscle strength, that women may have less muscle strength in the necks with some of the concussions, but a lot of it is conjecture at this point," said Ehlinger.
The study also indicated that high school sophomores suffered more concussions than student athletes at other grade levels.
"We were surprised to see that spike in sophomores," said Sarah Dugan, research analyst, "and it is unclear to us why that spike is there. We have several conjectures as to why that might be the case. One of them is athletes who are younger may be getting hit more often and they may be smaller players. Maybe some of the larger, older players are causing the concussion in the younger players.
"There may be fewer athletes in the higher grades and so, the sophomores, there may just be more of them."
Researcher and epidemiologist Jon Roesler said much more research is needed to answer many of the questions posed in the study.
"As we like to say in epidemiology, 'you cannot prevent, what you cannot count'. Our first step in this whole thing really comes down to being able to count these concussions," said Roesler. He indicated that it was necessary to expand the future studies to include high schools in greater Minnesota.
"The schools that we included in this were from the Twin Cities Metro area," said Roesler. "In this next year, we are opening this up to athletic trainers from high schools across the whole state. We got our first number. It is about 3,000 statewide. How good is that number? We are going to be looking at this next year as we expand the system."