British medical researchers led by Dr. Tony Goldstone published a study in September 2013 in the journal Annals of Neurology that compared 19 soldiers who had suffered moderate to severe TBI from blast injuries with 39 people who suffered the same level of brain injury from traffic accidents.
Using neuroimaging and hormonal testing they found that 32% of the blast-injured soldiers had suffered pituitary injuries while just 2% of the traffic accident victims did. Damage to the pituitary lowered secretion of human growth hormone (HGH) and caused the victims to suffer such symptoms as fatigue, a depressed mood, low emotional or social well-being, increased body fat, reduced muscle and thinning bones. Dr. Goldstone was able to reverse these symptoms by using HGH replacement therapy.
As for why soldiers with blast injuries suffered a much higher incidence of pituitary damage it is likely that the blast force exceeded the force of traffic accidents and penetrated deeper areas of the brain. Soldiers with blast injuries showed more widespread white matter connection damage and more severe cognitive problems.