Background:
The relationship between cytokines as markers of systemic inflammation and cognitive decline in the elderly has been established, whereas little knowledge has been gained as to whether domains of cognitive functioning are affected by cytokines. This study is to investigate the associations between circulating cytokines and specific neuropsychological domains of cognitive functioning (memory, processing speed and motor function) and general cognitive function (MMSE) in healthy elderly individuals.
Methods:
In a cross-sectional study of 369 community-dwelling elderly subjects, we examined the relationship between serum interleukin (IL)-1beta, sIL-4R, IL-6, IL-8, IL-10, IL-12 and tumor necrosis factor-alpha concentrations and cognitive performance using an extensive cognitive test battery.
Results:
Multivariate analysis showed that increased serum concentrations of IL-8 were associated with poor performance in the memory and speed domain and in motor function. Serum concentrations of IL-1beta, IL-6 and IL-10 were associated with impairments in specific domains of cognitive functioning, but these effects disappeared after Bonferroni's correction for multiple testing. Global cognitive functioning, as measured with MMSE, was not affected by cytokine levels.
Conclusions:
This study suggests an association between circulating IL-8 concentrations and cognitive dysfunction in the elderly. An interaction between this cytokine and glial cells may help explain the patho-physiological mechanisms leading to cognitive impairment in our study group.
