Study Links HIV and Increased Alzheimer’s Risk, Challenging Current Understanding
Boston, MA - A new study published September 9, 2025, in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association reveals a statistically meaningful association between HIV infection and an elevated risk of developing Alzheimer’s disease, even among individuals with well-controlled viral loads. Researchers at Brigham and Women’s Hospital and Harvard Medical School found that people living with HIV (PLWH) exhibited higher levels of biomarkers indicative of Alzheimer’s pathology compared to a control group without HIV.
The findings challenge the prevailing assumption that effective antiretroviral therapy (ART) fully mitigates the neurological risks associated with HIV. With an aging global population of PLWH - now exceeding 39 million worldwide as of 2024,according to UNAIDS – the potential for a surge in HIV-associated neurocognitive disorders,including Alzheimer’s,is a growing public health concern. This research underscores the need for increased neurological monitoring of PLWH and the advancement of targeted interventions to prevent or delay the onset of Alzheimer’s disease in this vulnerable population.
The retrospective cohort study analyzed data from 483 participants: 243 PLWH and 240 HIV-negative controls, all over the age of 50. Researchers assessed cerebrospinal fluid (CSF) biomarkers, including amyloid-beta and tau proteins, known to accumulate in the brains of Alzheimer’s patients. PLWH demonstrated significantly higher levels of phosphorylated tau (p-tau), a key indicator of neurofibrillary tangle formation, a hallmark of Alzheimer’s disease.
“We observed that even in individuals with HIV who were virally suppressed on ART, there was a discernible increase in Alzheimer’s-related biomarkers,” explained Dr. Costas Lyssiotis, lead author of the study and an associate professor of medicine at Harvard Medical School. “This suggests that HIV may trigger a cascade of inflammatory and neurotoxic processes that persist despite viral control, contributing to long-term neurological damage.”
The study did not establish a causal relationship between HIV and Alzheimer’s, but the strong association warrants further investigation. Researchers are now focusing on identifying the specific mechanisms by which HIV impacts alzheimer’s pathology, including the role of chronic immune activation and neuroinflammation. Future studies will also explore the potential benefits of early intervention strategies, such as cognitive training and lifestyle modifications, to mitigate the risk of Alzheimer’s disease in PLWH.
