Abstract: Objective  To study the relationship between serum homocysteine(Hcy), blood lipid levels and cognitive function in elderly patients with depression. Methods  Sixty elderly patients with depression were selected as study group, and 60 healthy volunteers were selected as normal control group. The serum levels of homocysteine (Hcy), total cholesterol (TC), triglyceride (TG), highdensity lipoprotein cholesterol (HDLC) and lowdensity lipoprotein cholesterol (LDLC) were measured in two groups. Hamilton Depression Scale (HAMD) was used to assess the severity of the disease, and Montreal Cognitive Assessment Scale (MoCA) was used to assess the cognitive function of the patients. Results  Compared with the normal control group, the MOCA score of  study group was significantly lower than that of  control group (P<0.05), the serum Hcy was significantly higher than that of  control group (P<0.05), and the serum HDLC level was significantly lower than that of  control group (P<0.05).The correlation analysis showed that the degree of cognitive impairment was positively correlated with the severity of the disease in study group(r=0.327, P<0.01). The three dimensions of attention and concentration, memory, executive function scores and  serum Hcy levels were negatively correlated in cognitive function assessment(r=-0.402，P=0.01). There was positive correlation between the executive function score and HDLC level(r=0.562，P=0.008). Conclusion  Cognitive impairment of the elderly patients with depression is related to high levels of Hcy and low levels of HDLC in serum. High levels of Hcy and low levels of HDLC in serum may be the risk factors for elderly patients with depression.

Key words: depressive disorder, cognitive function, serum , hcy; , blood lipid