The invention provides an application of a ratio of neutrophil to
lymphocyte in preparation or screening of a
cognitive disorder risk
diagnostic reagent. It is found that in APOE epsilon 4
allele carriers, increase of the NLR level is related to the high onset risk of
cognitive impairment of the APOE epsilon 4
allele carriers, meanwhile,
obesity further increases the
dementia occurrence risk of high-
inflammation people, and new evidence is possibly provided for synergistically promoting
dementia occurrence through metabolic disorders and
peripheral inflammation. In non-APOE epsilon 4
allele carriers, the high NLR level does not increase the
cognitive impairment occurrence risk of old people, and it can be seen that the influence of
inflammation on
cognition may be an important factor for impairment of the cognitive function of the APOE epsilon 4 allele carriers. Based on an ADNI
database, it is proved through longitudinal research that
peripheral inflammation plays an important role in gradual decline of the cognitive function of an APOE epsilon 4
gene carrier, the high NLR level is related to fast
cognitive decline, and deposition of Alzheimer's
disease neuropathology markers is promoted faster. On the other hand, the AD core
pathological marker plays an important role in regulating the NLR level and
cognition. The invention provides a novel
cognitive impairment risk diagnosis
reagent and a related device which are safe, convenient, non-invasive and economical and can be widely popularized, and the
reagent and the related device have great significance in improving the early recognition rate, realizing accurate intervention and optimizing treatment decision.