Learn about 4 sexually transmitted infections that can increase your risk of dementia, including syphilis cases up 700% in nursing homes. Prevention and treatment tips inside.
Sexually transmitted infections (STIs) can have far-reaching effects beyond an awkward conversation with a partner. Research indicates that certain STIs may raise the risk of developing dementia, a memory-robbing disease affecting 1 in 10 older adults in the U.S.
With STI cases skyrocketing — over 2.4 million reported in 2023 alone — older adults, especially those aged 65 and above, are increasingly vulnerable, as infections in this age group have more than doubled in the past decade.
More than 50% to 80% of Americans carry oral herpes (HSV-1), and 1 in 6 adults aged 14–49 has genital herpes (HSV-2). The herpes virus can enter the brain and remain dormant. When reactivated, it may trigger brain inflammation, potentially damaging cells and increasing the risk of dementia.
A 2024 study found that individuals with HSV-1, HSV-2, or both are up to 2.44 times more likely to develop dementia compared to those never infected.
2. Syphilis
Syphilis is making a major comeback in the U.S., with cases among adults 55+ increasing nearly 700% since 2010.
If untreated, syphilis can affect every organ system, including the brain and spinal cord. Advanced infection can lead to neurosyphilis, causing brain inflammation and tissue damage, which may result in syphilitic dementia. Early detection and treatment can reverse this type of dementia.
Approximately 400,000 Americans live with genital warts caused by certain strains of HPV. HPV may contribute to brain inflammation, a key factor in dementia development.
A 2020 study in Taiwan found that individuals with genital warts had a 49% higher risk of dementia. The HPV vaccine effectively prevents most genital warts and related cervical cancer.
4. HIV/AIDS
Around 1.2 million Americans are living with HIV. When the virus reaches the brain, it triggers inflammation, damages brain cells, and releases harmful toxins, increasing the risk of HIV-associated dementia.
A 2022 study of 13,000 Kaiser Permanente patients with HIV compared to 155,000 without found that 2.5% of HIV-positive individuals developed dementia over 16 years, versus 1.3% in the HIV-negative group.
A 2024 study involving over 344,000 participants found that individuals diagnosed with HSV-1 had an adjusted odds ratio of 1.80 for developing Alzheimer’s disease (AD), indicating an 80% increased risk.Moreover, those receiving antiherpetic treatment had a significantly lower risk of AD, with an adjusted hazard ratio of 0.83.PubMed+3PubMed+3PubMed+3
Syphilis (Neurosyphilis)
A 2020 study reported that 58.3% of patients with neurosyphilis, a severe complication of syphilis affecting the nervous system, developed dementia.
Conclusion
Awareness, regular STI screenings, and vaccinations like HPV can help prevent long-term complications, including dementia. Older adults, particularly those over 65, should take sexual health seriously and discuss it openly with healthcare providers.
