medwireNews: A large real-world study has found an association between herpes simplex virus type 1 (HSV-1) diagnosis and Alzheimer disease (AD) development, with the greatest risk among patients older than 75 years.
Moreover, patients diagnosed with HSV-1 who received antiherpetic treatment had a significantly decreased risk for AD compared with those who did not.
For the study, Yunhao Liu (Gilead Sciences Inc, Foster City, California, USA) and colleagues used claims data from the IQVIA PharMetrics Plus database in the USA.
They compared 344,628 patients aged 50 years or older, who had two or more AD or AD-related dementia (ADRD) diagnosis codes at least 30 days apart, or at least one AD or ADRD diagnosis code and at least one ADRD medication prescribed following diagnosis, with an equal number of control patients who had no history of neurological disorders. The participants were matched based on age, sex, region, and comorbidities. The mean age was 73 years and 65% were women.
Of the patients with AD, 0.44% had a history of HSV-1 diagnoses compared with 0.24% of controls. Conditional logistic regression showed that having an HSV-1 diagnosis increased the risk for AD 1.8-fold.
Writing in BMJ Open, the researchers note that “this association was found to be more pronounced in older age groups in an incremental manner.” Specifically, the odds ratio (OR) for AD among patients with versus without an HSV-1 diagnosis was 1.4 among those aged 50–70 years, 1.51 for those aged 71–74 years, and 2.1 for those 75 years of age and older.
The team also found that other herpesviruses, namely HSV-2 and varicella zoster virus, were associated with AD, although the herpesvirus cytomegalovirus was not significantly associated.
“Our results therefore point to HSV monitoring as a potential public health priority for AD management in individuals with a dementia family history,” say the authors.
They also highlight that among the 2330 participants with a history of HSV-1 diagnoses, 40% had used antiherpetics after diagnosis. These individuals were significantly less likely to develop AD than those who did not use antiherpetics, with a hazard ratio of 0.83 after adjusting for confounding factors.
“While the molecular mechanisms remain to be fully elucidated, these results are indicative of a possible role for antiherpetic therapy in mitigating dementia risk,” the researchers note.
They conclude: “These findings place an even greater emphasis on viewing the prevention of herpesviruses as a public health priority.”
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