Study On Prevalence And Risk Factors Of Mild Cognitive Impairment Among Retired Senior Cadres People

Background and objectiveThe prevalence of dementia is increasing with the increasing life expectancy . It should be noticed that dementia which become an important public health problem bring heavy burden to the patient, family and society . Owing to the poor treatment of middle-late of dementia , the dementia has no breakthrough in its treatment these years . Therefore, researches turn to a new study direction about early diagnosis and intervention of dementia. Age-related cognitive impairment with mild dementia is a new concept which puts forward for the past few years , namely mild cognitive impairment. The concept opens up a new situation in the field of dementia. The MCI signifies the transitional stage between age-related memory decline and early dementia. The memory impairment of MCI individuals is greater than that one would expect for their age and education, yet general cognitive function is preserved. Similarly activities of daily living are normal. But these subjects with cognitive impairment do not meet criteria for Alzheimer's disease. According to the core symptom of patients, The MCI can be divided into 3 clinical subtypes: (1) amnestic-type, aMCI;(2)multiple cognitive deficits MCI-MCDI;(3)single-nonmemory mild cognitive impairment. Long-term follow-up studies found that MCI tend to convert to clinically probable Alzheimer's disease as a rate of 10-15% per year, and dementia (Alzheimer's disease , AD) with about 2/3 transformed by MCI, So the MCI patients belong to high-risk groups of dementia. The MCI which is the same as many other mental diseases has no very specific biology marks. The clinical diagnosis is based on comprehensive analyses according to history taking, physical examination, the corresponding examinations. But making a definite diagnosis of dementia mostly depends on brain pathology. The MCI symptoms mainly perform cognitive function decline, such as memory, intelligent, speech and so on. So the brief and accute cognitive screening instrument is necessary to screen the MCI patient. The Mini-Mental State Examination (MMSE) is widely used for elderly people to screen cognitive impairment in our country at present. Meanwhile, the questions of sensitivity and specificity for screening MCI are received much attention. The Montreal Cognitive Assessment (MoCA) is a brief cognitive screening tool with high sensitivity and specificity for detecting MCI currently. It is reported that MoCA is better than the MMSE in terms of validity, reliability and sensitivity.The MCI may be the most appropriate intervention stage for early treatment of dementia. If we can take some effective measures to prevent or intervene for the MCI, it will reduce the progression probability from MCI to AD. So how to predict MCI and postpone MCI into dementia appear very important and urgent for clinical medicine. Consequently, it is very useful to find out and prevent risk factors of MCI for dementia. Recently the domestic and foreign researches have reported that senior , female , low education , widowed , solitude , life events , hypertension , diabetes mellitus , coronary disease , stroke and ApoEe4 polymorphisms allele are risk factors of cognitive impairment. The aim of this study is to investigate the prevalence of MCI among retired senior cadres people in Guangzhou city and explore the relationship between MCI and senior, gender, degree of education , smoke, drink, depression, obesity, exercise, quality of sleep, hypertension, coronary disease , diabetes mellitus, stroke, hypercholesterolemia, hyperuricemia. This will provide more effective reference for the clinical to intervene and treat the MCI.Methods1,The subjects mainly come from retired senior cadres people over 60 years old who take health examination in the Guangzhou No. 1 People's Hospital from 2009.05 to 2009.12. The following items were investigated: basic Condition,laboratory results and relevant history. All subjects( n=454) are administered the MMSE , MoCA , ADL and GDS to evaluate their cognition functione. According to the threshold values of MoCA and MMSE respectively , we analyse the relationship between the result of MoCA and MMSE. The detection rate of two screening instrument are also compared.2,The subjects are further diagnosed the MCI by clinic symptons and the score of MoCA scale, then this subjects are divided into two groups:patients with MCI(n=337, MoCA<26),patients with Cognitive norn1al controls(n=96, MoCA≥26). The related risk factors are analysed between two groups .3,All data are analyzed by SPSS 13.0 for windows. According to the threshold values of MoCA and MMSE respectively , the result of MoCA and MMSE is analyzed by linear correlation as a standard of MMSE scale. The positive detection rate of scales is analyzed by chi-aquare. The Descriptive statistics is assessed by mean±standard deviation. Continuous variables is tested by t-test (normal distribution) or Mann–Whitney nonparametric test (skewed distribution). Categorical variables adopts chi-square test. Multiariate analysis is assessed by logistic regression model.P<0.05 were selected as dominant difference.Results1,The result of MoCA and MMSE is analyzed by linear correlation as a standard of MMSE scale,and the score of MoCA closely correlated to MMSE(r=0.563, p<0.01), The positive detective rate of MoCA(74.2%)is higher than that of MMSE(43.8%)as a screening instrument for mild cognitive impairments.2,Whether total or subitems score of MoCA or MMSE , both of them in MCI group are lower than normal group. MoCA item: there are significant statistic difference in the field of visual/constructional skills, attention and concentration, calculations, language, conceptual thinking, delayed recall in the two group(P<0.01). And there is aslo statistic difference in the field of orientation(P<0.05), while not in the field of name ability between two groups. MMSE item: there are significant statistic difference in the field of short-term recall, concentration and calculations, delayed recall and follow a three-step verbal command between MCI and normal groups (P<0. 01). There are statistic difference in the field of orientation, written language instruction, drawing show statistic difference in two groups also(P<0.05),while not in the field of naming and repeating ability between two groups (P > 0.05).3,Single factor analysis shows that age, systolic pressure and ADL are extremely notable relevance with MC(IP<0.01). There are statistic difference between two groups in terms of depression scores, hypertension and diabetes mellitus and hyperlipemia(P<0.05). Logistic regression mode shows that age, hypertension, depression scores are independent risk factors of MCI(P<0. 01).Conclusions1,The MCI is very common in elderly people. the score of MoCA is closely correlated with MMSE. Therefore, MoCA is also suitable for screening to the elderly people with cognitive impairment. Owing to the high positive detection rate of MoCA, this tool maybe more suitable for elderly people to screen mild cognitive impairment quickly.2,The age, systolic pressure,hypertension, the score of depression, diabetes mellitus, hyperlipemia and ADL are relevant with cognitive impairement in two group. The age, hypertension, the score of depression are independent risk factors for MCI in elderly people. These results suggest that early interventions is one of the effective measures controlling these modifiable risk factors, and it may be reduce the conversion from MCI to AD.