Association Between Whole Blood Selenium And Mild Cognitive Impairment In Older Adults

ObjectivesIn this study,the baseline data of the Elderly Health and Environment Risk Factor Cohort（EHERF）in Lu’an City,Anhui Province were used to evaluate the influencing factors of cognitive impairment in the elderly,to understand the prevalence of mild cognitive impairment（MCI）in the elderly in Lu’an City,Anhui Province,to detect the concentration of elements in the whole blood of the elderly,and to ascertain the distribution of whole blood selenium（Se）concentrations and elemental ratios in the elderly in the region.A special study on the association between whole blood Se and MCI in the elderly was conducted to provide a scientific basis for the prevention and control of cognitive impairment in the elderly.MethodsThe survey was based on the EHERF jointly conducted by Anhui Medical University and the Center for Disease Control and Prevention in Lu’an City,Anhui Province from June to September 2016.The method used in the survey is stratified cluster sampling,and the principle of randomization is strictly followed.The elderly included must meet the following criteria:living in the local area for more than 6 months and being over 60 years old.A total of 1080 people were surveyed in the field,and finally 1010 people were included in this analysis.Mini-mental State Examination（MMSE）and Activity of Daily Living Scale（ADL）were used to evaluate the cognitive status of the elderly.The peripheral venous blood was collected by trained medical staff,and blood samples were stored,transported and detected by trained laboratory personnel.The concentration of trace elements in whole blood was detected by Inductively Coupled Plasma Mass Spectrometer（ICP-MS）.The data collected were inputted by Epi Data3.1 software and the database was established.SPSS 23.0 and Graph Pad Prism 8.0 software were used for statistical description,statistical analysis（χ^）test,Mann-Whitney U test and Logistic regression analysis,etc.)and mapping,and stratified analysis of the study population.ResultsThe study finally included and analyzed baseline data from 1010 older adults with a mean age at 71.72±6.38 years,of whom 54.5%were women and 45.5%were men.There were208 patients with MCI,with a detection rate of 20.6%.There were significant differences in age,sex,marital status,education level,BMI,self-assessment of health status,living alone,drinking frequency between normal people and MCI people（P<0.05）.The detection rate of element Se is 100%.The geometric mean of whole blood Se concentration was 89.64μg/L,the standard deviation was 25.93μg/L,and the median was 89.18μg/L.There were significant differences in the distribution of whole blood Se concentration among different age groups,marital status,education level,BMI,drinking frequency and MCI（P<0.05）.The results of the logistic regression analysis showed that compared with low Se concentration,risk of MCI in older adults decreases with increasing Se concentration（OR₁=0.307,95%CI:0.207-0.456）.After adjusting the correlation covariates,risk of MCI in older adults remains inversely proportional to Se concentration（middle Se:OR₃=0.540,95%CI:0.356-0.820;high Se:OR₃=0.394,95%CI:0.247-0.630）.By gender and age stratification,compared with the female elderly with low Se concentration,the female elderly with high Se concentration had a lower risk of MCI（OR₃=0.498,95%CI:0.272-0.912）,and the difference was statistically significant（P<0.05）.In the elderly aged 70-79 years old,the risk of MCI gradually decreased with the increase of whole blood Se concentration（OR₃=0.322,95%CI:0.156-0.666）,and the difference was statistically significant（P<0.05）.Analysis of the relationship between elemental ratios and MCI found that the risk of MCI in the elderly with high Cu/Se ratio was 1.975 times that of low ratio（95%CI:1.352-2.886）,the risk of MCI in the elderly with a high Mg/Se ratio was 1.906 times that of a low ratio（95%CI:1.312-2.768）.ConclusionsThe overall detection rate of MCI in older adults aged≥60 years in Lu’an City,Anhui Province,was 20.6%,with a greater risk of developing MCI in older adults who were older,female,unmarried,illiterate,living alone,had a lower BMI,had never consumed alcohol,and had suffered a stroke.The detection rate of Se in whole blood was 100%.There is a negative correlation between high concentration of Se and the risk of MCI in the elderly.And stratified analysis found that women or the elderly are more likely to occur in the association between high levels of Se and the risk of MCI in the elderly.Compared with low Cu/Se and Mg/Se ratios,the elderly with high ratios had a higher risk of MCI.