Low levels of the male sex hormone, testosterone, in older men is associated with the onset of Alzheimer's disease

Researchers studied 153 Chinese men who were recruited from social centers. They were at least 55 years and older, lived in the community and didn't have dementia. Of those men, 47 had mild cognitive impairment - or problems with clear thinking and memory loss. Within a year, 10 men who all were part of the cognitively impaired group developed probable Alzheimer's disease. These men also had low testosterone in their body tissues; elevated levels of the ApoE 4 (apolipoprotein E) protein, which is correlated with a higher risk of Alzheimer's disease; and high blood pressure. The findings corroborate findings in previous studies of older Caucasian men that show low testosterone is associated with impaired thinking and Alzheimer's disease. They suggest that testosterone may have a protective value against Alzheimer's disease.