Subtype D may cause 1 of leading types of dementia worldwide
Patients infected with a particular subtype of HIV, the virus that causes AIDS, are more likely to develop dementia than patients with other subtypes, a study led by Johns Hopkins researchers shows. The finding, reported in the September Clinical Infectious Diseases, is the first to demonstrate that the specific type of HIV has any effect on cognitive impairment, one of the most common complications of uncontrolled HIV infection.
HIV occurs in multiple forms, distinguished by small differences in the virus' genetic sequence and designated by letters A through K. Certain subtypes appear to cluster in particular areas of the world, and others have been associated with different rates of progression to full blown AIDS. Of the 35 million people living worldwide with HIV, the majority live in sub-Saharan Africa, where subtypes A, C and D dominate.
Nearly half of patients with advanced HIV infections have at least mild cognitive impairments, and about 5 percent have the severe form of cognitive impairment known as dementia.
In earlier research, Ned Sacktor, M.D., and his colleagues found that about 31 percent of patients visiting an infectious disease clinic in the Ugandan capital, Kampala, where subtypes A and D dominate, had dementia. The finding led him and his team to wonder whether patients with different subtypes had different rates of dementia.