MAPT and Alzheimer disease: Contact sports may therefore impose an increased health risk promoting the silent development of specific tauopathies (CTE, AD, etc) and progression of the pathology.7,28 Because the upregulation of p-tau could precede the development of the obvious pathological signs in behavior,22 we urge more precautions in contact sports, especially those in which, although very mild, repetitive head impacts are frequent, such as ball heading in soccer.