Both diabetes and hypertension predict a shorter lifespan in people diagnosed with Alzheimer's disease, according to a new study published in the November 4, 2008 issue of the journal Neurology.

Researchers from the Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University Medical Center in New York City studied 323 patients aged 65 years and older who were initially free of dementia, but were then diagnosed with Alzheimer's. When they looked at mortality rates, the researchers found that Alzheimer's patients who had a history of diabetes or a history of high blood pressure had a shorter survival than those who did not.

Interestingly, while diabetes and hypertension are more common among Hispanics than the general population, Hispanics seemed to have a longer lifespan after Alzheimer's diagnosis than both non-Hispanic whites and African-Americans. The researchers suggest that this possible survival advantage may be due to health-related behaviors, family networks, and social support.

Both diabetes and hypertension are controllable risk factors, and further studies are needed to determine whether good control of blood sugar and blood pressure affect Alzheimer's survival.