Interleukin-1 alpha (rs1800587) genetic polymorphism is associated with specific cognitive functions but not depression or loneliness in elderly males without dementia.

Inflammatory process is considered to be a pathway that results in neurodegeneration, and numerous plasma cytokines have been examined for their association with cognitive function and depression. Interleukin-1 alpha (IL-1A) genetic polymorphism (rs1800587) has been found to be associated with Alzheimer's disease susceptibility. The aim of this study was to investigate the effect of IL-1A rs1800587 genetic effects on cognitive functions, loneliness and depression severity in elderly males without dementia or major depression. 192 non-demented Chinese elderly male were recruited and underwent Cognitive Abilities Screening Instrument (CASI), Wechsler Digit Span Task, Geriatric Depression Scale-short form, and UCLA Loneliness Scale assessment. IL-1A rs1800587 is a C to T transition at position -889. Compared to the C/C carriers, the T allele carriers had significantly overall higher CASI score (p=0.017) after using age and total education years as co-variates. This was especially true in the four distinct domains of long-term memory (p<0.001), orientation (p=0.017), visual construction (p=0.003), and list-generating fluency (p=0.020). This polymorphism is not associated with Geriatric Depression Scale-short form or UCLA Loneliness Scale. Our data supports that the T allele of IL-1A rs1800587 genetic polymorphism is associated with better cognitive function in the elderly. Further research will be needed to better understand the molecular mechanism for IL-1A genetic effects on cognitive function in the elderly.