Homocysteine and inflammation: Predictors of cognitive decline in older persons?

Abstract 

The aim of the current study was to examine the association between homocysteine and 6-year cognitive decline, and the modifying role of the inflammatory markers Interleukin-6 (IL-6), C-reactive protein (CRP) and alpha-1-antichymotrypsin (ACT). Data were collected within the Longitudinal Aging Study Amsterdam (ages ≥65 years) and analyzed using multiple longitudinal regression models (N=1257 of whom N=1076 had longitudinal data). Cognition was measured with the Mini-Mental State Examination (general cognition), Auditory Verbal Learning Test (memory), Coding Task (information processing speed) and Raven Coloured Progressive Matrices (fluid intelligence).

Higher homocysteine at baseline was negatively associated with prolonged lower cognitive functioning and a faster rate of decline in information processing speed and fluid intelligence. The negative association between higher homocysteine and immediate recall was strongest in persons with a high level of IL-6. Only in the highest tertile of CRP, higher homocysteine was negatively associated with retention. In the middle tertile of ACT, higher homocysteine was associated with lower information processing speed and faster decline. Both in the lower and middle tertile of CRP, higher homocysteine was associated with a faster rate of decline in information processing speed. The results implicate that a combination of both risk factors may be used as a marker for cognitive impairment.

Keywords: Homocysteine, Cognitive decline, Inflammation, Longitudinal population-based study