An international study led by Johns Hopkins suggests that the rate of HIV-associated dementia is so high in sub-Saharan Africa that HIV dementia along with Alzheimer's disease and dementia from strokes may be among the most common forms of dementia in the world.

In the first study of HIV dementia on the African continent usingrigorous neurological and neuropsychological tests, 31 percent of a small but presumably representative group of HIV-positive patients in Uganda were found to have HIV dementia, according to Ned Sacktor, M.D.,a Johns Hopkins neurologist and senior author of a multi-institutional
study that will be published Jan. 29 in Neurology.

HIV dementia is defined as memory, learning, behavioral and motor disabilities that interfere with normal daily life and in extreme cases lead to total disability and a bedridden state. Unlike Alzheimer's- and stroke-induced dementia, HIV dementia is treatable and potentially reversible with the same antiretroviral medication that is used to treat the infection. Treatment can even restore completely normal cognitive
function to some of those affected.

The study looked at 178 subjects in Kampala, Uganda, from September 2003 to January 2004. Seventy-eight were HIV-positive patients recruited from the Infectious Disease Clinic in Mulago Hospital, Makerere University, and 100 were HIV-negative individuals recruited from the AIDs Information Center who were used to obtain normative data for the cognitive tests.

In diagnosing HIV dementia, researchers looked at medical history and the results of a series of comprehensive neurological and neuropsychological tests and functional assessments.

"Clearly, large-scale testing would have to be conducted before we know the global reach of HIV dementia, but this study sends a clear message that it exists in high proportions in sub-Saharan Africa and is an under-recognized condition that needs to be studied and treated,"
Sacktor says.

Of the estimated 40 million adults and children worldwide who are living with HIV infection, an estimated 27 million live in sub-Saharan Africa, according to Sacktor.

"If the rate we saw in our study translates across sub-Saharan Africa, we're looking at more than 8,000,000 people in this region with HIV dementia," says Sacktor.

Sacktor says an extremely high rate of HIV dementia in Africa and other poor regions of the world adds enormously to the social and economic burden of their populations and governments. Dementia not only disrupts jobs and adds to the cost of care, but also interferes with a patient's ability to adhere to a regular course of antiretroviral medication,
thus increasing the risk of drug resistance. People with dementia also are less likely to practice safe sex.

Before antiretroviral medications were available in the United States, the U.S. rate of HIV dementia was similar to what was discovered in this study in Uganda, says Sacktor. Unfortunately, he says, only 20 percent of people infected with HIV in the world are getting treatment.

"We hope studies like these will shed additional light on the
devastating problem of HIV in resource-limited countries like Uganda and encourage more programs that bring much-needed medication to these poor regions of the world," Sacktor says.

Sacktor says there's little accurate data about HIV dementia patients in other parts of the world --- current estimates of the number of HIV-positive patients who have dementia range from 9 percent to 54 percent.

Additional researchers who worked on the study include Matthew Wong, M.D., from the University of Virginia; Richard Skolasky, M.A., from Johns Hopkins; Kevin Robertson, Ph.D., from the University of North Carolina; Noeline Nakasujja, M.B., Ch.B., Seggane Musisi, M.B., Ch.B., and Elly Katabira, M.B., Ch.B., from Makerere University, Kampala, Uganda; and Allan Ronald, M.D., from the University of Manitoba, Winnipeg, Canada.