Association between human herpesvirus 6 (HHV-6) and cognitive function in the elderly population in Shenzhen, China.

AIM: Human herpesvirus 6 (HHV-6) is neurophilic, and its relationship with Alzheimer's disease (AD) remains controversial. This study aimed to examine the relationships between HHV-6 and cognitive abilities in elderly people aged 60 years or above from communities in Shenzhen. METHODS: We recruited participants from 10 community health service centers in Shenzhen. Participants were divided into case and control groups according to Mini-Mental State Examination (MMSE) scale standards and were included in this study with 1:1 matching based on sex and age (± 3 years). The HHV-6 gene was detected by real-time fluorescent quantitative PCR, and the HHV-6 copy number was quantified. RESULTS: A total of 580 participants (cases, n = 290; controls, n = 290), matched for gender and age was included in this study. A positive HHV-6 test was not associated with a significant difference in global cognitive performance (ORadjusted = 1.651, 95% CI = 0.671-4.062). After adjusting for gender, age, education, Pittsburgh Sleep Quality Index (PSQI) score, homocysteine (Hcy) and glycosylated hemoglobin (HbA1c), the results of multiple linear regression showed that there was a statistically negative correlation between HHV-6 copy number and orientation (ßadjusted = -0.974, p = 0.013), attention and calculation (ßadjusted = -1.840, p < 0.001), and language (ßadjusted = -2.267, p < 0.001). The restricted cubic spline (RCS) model results showed that there was a nonlinear dose-response relationship between HHV-6 log10-transformed copies and orientation (poverall = 0.003, pnonliner = 0.045), attention and calculation (poverall < 0.001, pnonliner < 0.001), and language (poverall < 0.001, pnonliner = 0.016). CONCLUSIONS: HHV-6 infection significantly associated with orientation, attention and calculation, and language in elderly individuals.