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Experts caution that sexually transmitted diseases (STDs) may be partially responsible for the escalating dementia cases in the United States, raising concerns about public health.
Recent government data reveals a nationwide surge in STDs such as syphilis, chlamydia, and herpes, affecting approximately one in every 100 Americans. This rise is particularly pronounced in nursing homes and among older adults.
The increase is largely attributed to factors including the growing popularity of dating applications, inadequate sex education, and limited access to healthcare services. Untreated STDs can lead to severe health issues, including infertility and certain cancers.
However, new research indicates a potential link between STDs and an elevated risk of dementia, a debilitating cognitive disorder currently affecting an estimated 7 million individuals in the US. This number is projected to nearly double by 2060.
Researchers have indicated that while further investigation is warranted, studies suggest that infections like syphilis, herpes, and human papillomavirus (HPV) may potentially infiltrate the brain, triggering inflammation and neuronal damage. This is especially concerning for older adults, who are experiencing higher rates of STD transmission, as the risk of dementia doubles every five years after the age of 70.
Medical professionals advise adults who have or are at risk of contracting an STD to abstain from sexual activity or consistently use condoms to minimize the likelihood of transmission.
STDs are transmitted through sexual contact, including kissing, oral sex, and penetrative intercourse. Some studies have specifically linked oral sex to a heightened risk of herpes (stock image).
Data from the Centers for Disease Control and Prevention (CDC) indicates that approximately one in 100 adults in the US has a sexually transmitted infection (STI), encompassing over 209,000 syphilis cases, more than 600,000 gonorrhea cases, and in excess of 1.6 million chlamydia cases.
In 2023, there were 2.4 million reported STIs, representing a three percent increase compared to the prior year.
The CDC estimates that STDs have surged by 90 percent in the last two decades.
Herpes
Herpes is among the most prevalent STDs, categorized into two main types: HSV-1 and HSV-2.
Dr. Daniel Atkinson, Clinical Lead at Treated.com, explained to DailyMail.com that HSV-1 typically manifests as blisters and cold sores around the mouth (oral herpes), while HSV-2 is commonly associated with genital herpes.
He added, “Both forms of herpes can be asymptomatic, facilitating unintentional transmission to sexual partners.”
Nearly half of American adults carry HSV-1, and one in eight has HSV-2.
Herpes gained renewed attention following a University of Chicago study examining the effects of HSV-1 on mice.
Transmission of herpes typically occurs through direct contact with a cold sore when the virus is actively shedding. Genital herpes can also result from oral sexual contact.
The aforementioned study discovered that HSV-1 interferes with an enzyme called heparanase (HPSE), causing elevated inflammation levels.
The CDC reported in November that there are indications of a slowdown in the STI epidemic after a significant 90 percent increase over the past 20 years.
The graph illustrates the rate per 100,000 individuals for total syphilis cases in the US since the 1940s, revealing a recent upward trend.
This inflammatory response, triggered when HSV-1 reaches the brain via the trigeminal or olfactory nerves through the nose, may contribute to brain damage associated with dementia.
However, researchers emphasize that HSV-1 brain infections remain infrequent, occurring in only two to four cases per million individuals with the herpes virus.
In the mouse experiment, those infected with HSV-1 through nasal administration exhibited memory impairment, anxiety, and balance issues—all potential early signs of dementia—within a six-month period.
Furthermore, a Swedish study from November, spanning 15 years and involving over 1,000 participants, revealed that individuals with prior HSV-1 infection were twice as likely to develop dementia compared to those without infection.
Experts propose that recurrent herpes flare-ups could induce systemic inflammation, impacting and damaging delicate brain tissue.
A 2024 South Korean study analyzing health records of 750,000 adults also found a higher likelihood of developing dementia in individuals with HSV and varicella zoster virus (VSV), the cause of chickenpox and shingles.
The research team suggests that these viruses might damage neurons in the brain.
Dr. Atkinson acknowledged that while these study results are noteworthy, “further research is essential to solidify the connection between herpes and dementia.” He also pointed out that many studies have demonstrated associations rather than definitive causation.
Syphilis
Dr. Atkinson highlighted that while evidence concerning herpes remains under investigation, “clear associations exist between dementia and other STDs.”
Untreated syphilis can progress to neurosyphilis, affecting the brain and spinal cord and causing potentially damaging inflammation.
Dr. Atkinson told DailyMail.com, “Neurosyphilis can manifest as rapidly progressing dementia, personality changes, and occasionally paralysis.”
CDC data indicates an 80 percent surge in syphilis cases between 2018 and 2022, attributed by experts to decreased condom use and increased drug use.
Recent studies suggest that only one in four US adults between 18 and 44 years old reported using a condom during their last sexual encounter.
HIV and HPV
Dr. Atkinson also noted that individuals with HIV may face an elevated dementia risk, as the virus can induce “cognitive and motor impairments.”
This condition is known as HIV dementia or HIV-associated neurocognitive disorder (HAND). Management involves medications to reduce HIV viral load and lifestyle modifications, such as regular exercise.
HPV, encompassing over 200 virus types affecting almost every American at some point and currently impacting 40 percent of the US population, has additionally been associated with increased dementia risks.
A 2020 study in the Journal of Dermatology, utilizing health insurance data from 16,000 patients in Taiwan, indicated that individuals with genital warts from HPV had a 49 percent higher risk of developing dementia.
However, researchers emphasized that these findings demonstrated a correlation, not a definitive cause-and-effect relationship.
Furthermore, a 2024 study published in the International Journal of Gynecological Cancer reported a 1.6-fold increased risk of dementia in patients with cervical cancer.
Cervical cancer, predominantly caused by HPV in 99 percent of cases according to CDC estimates, affects 13,800 US women annually and results in 4,300 deaths.
The study authors stated, “These results imply that cancer-causing HPV infections might have a relationship with dementia.”
They cautioned that further research is needed to fully understand this connection.
Gonorrhea
Recent studies suggest a potential link between gonorrhea and dementia.
A 2022 study in Molecular Biology and Evolution identified a mutation in the CD33 gene, an immune cell receptor, that protects against cognitive decline, potentially influenced by the evolution of gonorrhea bacteria.
However, gonorrhea is among the few STDs showing a decline in the US, with rates decreasing by seven percent between 2022 and 2023.
Key Takeaway
Dr. Atkinson reiterated that while ongoing research is critical to understand the relationship between STDs and dementia, “it remains crucial to prevent infection transmission, regardless of age.”
“During symptomatic outbreaks, abstain from vaginal, anal, or oral sex, or utilize condoms to minimize the risk of passing on the infection,” he advised.