Professional boxers and football players who continually suffer blows to the head may increase their risk of developing Alzheimer's disease later in life. According to a new report published in this month's issue of The Journal of Neuroscience, mice that were subjected to head trauma developed a protein deposit, amyloid beta, which is associated with Alzheimer's.

While doctors involved in the study claim the results demonstrate "a direct cause and effect relationship between repetitive concussions and Alzheimer's," skeptics note that differences between mice and humans make the study's results less convincing.