Recent studies show certain people may be at greater risk for traumatic brain injuries (TBIs).

Reported by PBS earlier this year, a study found that military men with multiple TBIs have a greater likelihood of suicidal thoughts. While service members serving in the Iraq and Afghanistan wars often experienced TBIs, possibly resulting from IEDs but also occurring in training, those who had previously sustained a head injury were at a greater risk.

The study found that 22 percent of service members who experienced more than one TBI had suicidal thoughts or preoccupations, while only six percent of those who experienced one TBI had such feelings. Those without a TBI did not have suicidal thoughts.

As well, service members who had been through more than one TBI were more prone to PTSD and depression, the data showed.

It’s estimated that 266,810 out of the 1.6 million that served in Iraq and Afghanistan from 2000 to 2012 may have had at least one TBI, and more are likely undiagnosed.

However, TBIs hit closer to home with high school football, where an estimated four percent of participants may have a concussion at some point.

A piece on revealed that a 17-year-old student from Hopi High School in Arizona passed away on November 11 as a result of a TBI. After scoring a touchdown at a playoff game, the student was tackled, causing the injury.

As risks between head injuries and football recently surfaced, participation in Pop Warner football significantly dropped between 2012 and 2013, with an estimated 10-percent decline.

Yearly, 1.4 million people experience a TBI, according to the CDC. Not just from sports and combat, an open or closed head injury may result from a car or motorcycle accident or even a slip and fall. Symptoms may surface months later, such as memory loss and forgetting basic skills and body functions.