Effects Of Folic Acid And Vitamin B₁₂ On Mild Cognitive Impairment In Elderly People: Case-Control And Intervention Study

Objective1.The aim of the case-control study was to explore the relationship between serum folic acid,vitamin B₁₂ and homocysteine levels and mild cognitive impairment（MCI）.2.To observe the effects of folic acid and vitamin B₁₂2 on community MCI patients by intervention study,and evaluate the independent and associative effects of folic acid and vitamin B₁₂ on cognitive function improvement,providing scientific basis for the further development of community elderly MCI.Methods1.The 101 cases of MCI patients screened by the baseline survey were the case group,in addition,101 cases of healthy elderly were selected as normal control group.The subjects who were included in the study were collected blood samples on an empty stomach.Hcy was detected with Homocysteine Kit,Serum folate and vitamin B₁₂ were analyzed with chemiluminescent immunoassay,SAM and SAH were detected with highperformance liquid chromatography.The relationship between MCI and the above factors was analyzed by means of paired t test,chi-square test,non-parametric test and Logistic regression analysis.2.The MCI patients selected by the baseline survey were randomly divided into four groups and 60 members in each group.The folic acid intervention group took oral folic acid 800μg/d,the vitamin B₁₂2 intervention group took oral vitamin B₁₂25μg/d,the joint intervention took oral folic acid 800μg/d and vitamin B₁₂ 25μg/d,one group was given vitamin C 100mg/d as a control group.The patients were followed up for 6 months.Analysis and evaluation the blood biochemical indicators,simple mental health scale（mini-mental state examination,MMSE）score,wechsler adult intelligence scale（wechsler adult intelligene scale,WAIS）score and memory scale score of the control group and intervention group,vitamin B₁₂,folic acid intervention group and folic acid and vitamin B₁₂ joint intervention group at the baseline phase and intervention after six months.The intervention effect was evaluated by repeated measurement variance analysis.Results1.Case-control study found that compared to the control group,the folic acid（P<0.05）,vitamin B₁₂（P<0.05）,SAM concentration（P<0.05）and SAM/SAH（P<0.05）were significantly reduced in MCI group.The SAH（P<0.05）and Hcy concentration（P<0.05）in the MCI group were significantly higher than that in the control group.Moreover,there were significant differences in the proportion of folate levels,vitamin B₁₂2 levels and Hcy levels in the MCI group and the normal control group（P<0.05）.Logistic regression analysis found that folic acid（OR:1.317,95%CI:1.125¹.541）,and vitamin B₁₂（OR:0.971,95%CI:0.960⁰.985）,Hcy（OR:1.371,95%CI:1.179¹.595）,SAH（OR:1.071,95%CI:1.042¹.100）,SAM（OR:0.997,95%CI:0.994¹.000）,SAM/SAH（OR:1.834,95%CI:1.306².574）were associated with MCI was statistically（P<0.05）.Multi-factor analysis results show that high serum folate level（OR:0.105,95%CI:0.014⁰.795）,high serum vitamin B₁₂ level（OR:0.373,95%CI:0.202⁰.691）and normal serum Hcy level（OR:0.236,95%CI:0.133⁰.421）were protective factors;High serum Hcy level（OR:7.341,95%CI:2.110²5.547）was a risk factor of the occurrence of MCI（P<0.05）.2.The results of the intervention studies have shown that intervention after six months,compared with control group,the intervention group,vitamin B₁₂,folic acid intervention group and the combined intervention group of folic acid,vitamin B₁₂,SAM,SAM/SAH levels increased significantly（P<0.05）,Hcy,SAH levels significantly decreased（P<0.05）.The intervention group found that the changes in folic acid,vitamin B₁₂,Hcy,SAM,and SAM/SAH levels were more significant in the intervention group compared with the folate intervention group and the vitamin B₁₂intervention group.Compared with control group,the intervention group,vitamin B₁₂,folic acid intervention group,and the joint intervention group of wechsler scale speech score of knowledge,arithmetic,digit span,vocabulary part increased significantly,operating points in mapping arrange part increased significantly（P<0.05）,block diagram,graphics,memory scale scores were significantly increased（P<0.05）.The intervention group showed more significant changes in the intervention group than in the folic acid intervention group and the vitamin B₁₂ intervention group（P<0.05）.Conclusions1.There were differences in serum folic acid,vitamin B₁₂,Hcy and plasma SAH,SAM and SAM/SAH levels in the MCI group and the control group,all of which were related to MCI.High serum folate level,high serum vitamin B₁₂ level and normal serum Hcy level were protective factors for MCI.High serum Hcy level is a risk factor for MCI.2.Folic acid and vitamin B₁₂ in patients with MCI and joint after the intervention,can obviously increase the serum folate,vitamin B₁₂,plasma level of SAM,SAM/SAH,reduce serum Hcy,plasma levels of SAH,and joint intervention effect more pronounced.Folic acid,vitamin B₁₂ and joint intervention can significantly improve the cognitive ability of MCI elderly,and the intervention changes are more obvious.