Objective: To study the frequency of vasectomy in men with primary progressive aphasia (PPA).
Background: PPA is a dementia syndrome in which aphasia emerges in relative isolation during the initial stages of illness. On the basis of a clinical observation in a patient who dated the onset of symptoms to the period after a vasectomy, and because of the curious sharing of the tau protein exclusively by brain and sperm, vasectomy rates were examined in men with PPA.
Method: This study used a case control design. Forty-seven men with PPA and 57 men with no cognitive impairment (NC) between 55 and 80 years of age were surveyed about a history of vasectomy.
Results: The age-adjusted rate of vasectomy in PPA patients (40%) was higher than in NC (16%, P=0.02). There was a younger age at onset for the patients with vasectomy (58.8 vs. 62.9 y, P=0.03).
Conclusions: Vasectomy may constitute one risk factor for PPA in men. Potential mechanisms mediating risk include vasectomy-induced immune responses to sperm, which shares antigenic epitopes with brain. Antisperm antibodies can also develop in women and become risk factors for PPA.
*Cognitive Neurology and Alzheimer's Disease Center
Departments of †Neurology
‡Psychiatry and Behavioral Sciences
§Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
Funding: Supported in part by Alzheimer's Disease Core Center grant (AG13854) from the National Institute on Aging to Northwestern University, Chicago, IL.
Reprints: Sandra Weintraub, PhD, Cognitive Neurology and Alzheimer's Disease Center, 320 East Superior, Searle 11-467, Chicago, IL 60611 (e-mail: email@example.com).
Received for publication June 1, 2006; accepted August 31, 2006