Individuals with herpes simplex virus (HSV) infections may have a 2.56-fold increased risk for dementia and the use of antiherpetic medications was associated with a decrease in dementia risk, according to research published in Neurotherapeutics.1
A retrospective cohort study using Taiwan’s National Health Insurance Research Database identified 8362 patients with new HSV infections and 25,086 randomly selected sex- and age-matched controls without HSV.
Results of a multivariable Cox proportional hazards regression model indicated an adjusted hazard ratio of 2.56 (95% CI, 2.351-2.795; P <.001) for dementia in patients with HSV compared with controls. A reduction in risk was found upon treatment with antiherpetics (adjusted HR = 0.092; 95% CI, 0.079-0.108; P <.001).
There were several limitations to the study. The use of claims data allowed patients with dementia to be identified but no data on severity or stage were available, nor were data on antiherpetic treatment durations. Confounding factors such as education and genetic and dietary factors were also not available from the claims dataset. There were no imaging or other laboratory data available, so investigators relied on physician diagnosis.
Furthermore, the investigators noted that while “several community studies have revealed that Alzheimer dementia is the most common cause of dementia, followed by vascular dementia, and mixed or other dementias,”2-4 most of the dementias in this study were other types of dementia. This may have been missed since there was no evidence of previous cerebrovascular events and the dataset did not include information on APOE-e4 genotype. “Further studies are, therefore, warranted to determine the APOE genotypes in HSV-infected patients and controls” to “explore the underlying mechanism(s) of this association,” concluded the investigators.
- Tzeng NS, Chung CH, Lin FH, et al. Anti-herpetic medications and reduced risk of dementia in patients with herpes simplex virus infections-a nationwide, population-based cohort study in Taiwan [published online February 27, 2018]. Neurotherapeutics. doi:10.1007/s13311-018-0611-x
- Liu CK, Lai CL, Tai CT, et al. Incidence and subtypes of dementia in Southern Taiwan: impact of socio-demographic factors. Neurology. 1998;50:1572-1579.
- Liu HC, Lin KN, Teng EL, et al. Prevalence and subtypes of dementia in Taiwan: a community survey of 5297 individuals. J Am Geriatr Soc. 1995;432:144-149.
- Lin RT, Lai CL, Tai CT, et al. Prevalence and subtypes of dementia in Southern Taiwan: impact of age, sex, education, and urbanization. J Neurol Sci. 1998;1601:67-75.