Testosterone - the high and low

Low Testosterone Linked to Alzheimer's Disease

According to a research led by Leung-Wing Chu (1), a specialist in geriatric medicine at the University of Hong Kong , low levels of the male sex hormone, testosterone, in older men is associated with the onset of Alzheimer's disease.

The researchers studied 153 ambulatory community-living non-demented Chinese older men, aged 55 years or over. 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.

Higher Testosterone May Raise Risk of Heart Disease in Elderly Men

On the other hand, a large U.S. multicenter study (2) shows that older men with higher testosterone levels are more likely to have a heart attack or other cardiovascular disease in the future.

Researchers led by Kristen Sueoka studied 697 community-dwelling men age 65 or older who were participating in the National Institutes of Health-funded study, Osteoporotic Fractures in Men (MrOS). None of these men were receiving testosterone therapy, according to the study abstract.

During an average follow-up of nearly 4 years, 100 men, or about 14 percent, had a coronary disease event, in particular, heart attacks. After the researchers adjusted for other potential contributing risk factors for heart disease, such as elevated cholesterol, they found that higher total testosterone level relates to an increased risk of coronary disease.

Men whose total testosterone was in the highest quartile (greater than or equal to 495 nanograms per deciliter, or ng/dL) had more than twofold the risk of coronary disease compared with men in the lowest quartile (below 308 ng/dL). CLICK HERE for normal testosterone levels in men, which depends on many factors, including increasing age.

"Many in the general public are using testosterone supplements for various medical problems, including low sex drive and mood disorders, which are not life-threatening. These men may unknowingly be placing themselves at higher risk for cardiovascular disease," Dr Sueoka said.

If you are concerned about your level of testosterone, talk to your doctor.

Reference:

1. Chu LW, Tam S, Wong RL, Yik PY, Song Y, Cheung BM, Morley JE, Lam KS. Bioavailable Testosterone Predicts a Lower Risk of Alzheimer’s Disease in Older Men. Journal of Alzheimer's Disease, 2010; 21 (4)
   
2. Sueoka KT. OR17-1. Presented at: The Endocrine Society 92nd Annual Meeting and Expo; June 19-22, 2010; San Diego.
3. CLICK HERE for our other posts on testosterone.
4. Picture Credit