One explanation for this is that

Brain Plus IQ One explanation for this is that military personnel are below a high risk for physical working in car accidents, which are the most common cause of all TBIs. In optional accessory, military personnel are consistently at risk of swine hurt by powerful munitions, which can in addition to cause a brain deaden through concussive force. Though military further does exposed personnel to the risk of a penetrative brain offend, such as caused by a bullet or shrapnel, an even greater risk exists for a TBI caused by a concussive blast nod so of an explosive. A 2005 psychoanalysis in the New England Journal of Brain Plus IQ Medicine qualified these well along numbers in part to advancements in munitions, especially improvised explosive devices, and in part to improvements in body armor, which protects soldiers from what would to the lead have been a fatal penetrative wound, but not from a nonfatal blast outrage. The high occurrence of explosions due to improvised explosive devices (IEDs) in battle theaters such as Iraq and Afghanistan means American troops in the ground are at a tall risk of incurring a TBI.

http://ultimatemuscleblackeditionrev.com/brain-plus-iq-scam/