Investigation of the incidence of mild cognitive impairment and its risk factors in an elderly population sample in Beijing area

Objective To investigate the incidence of mild cognitive impairment(MCI)and its risk factors in an elderly population sample in Beijing area.Methods A sampling survey in 1865 aged subjects(≥ 65 years old)was established in Beijing area in 2004.The diagnosis of MCI was established according to the questionnaires and clinicians' examinations.1750 subjects with complete data about MCI were selected in this study and the risk factors were analysis.Results ①Of the 1750 subjects,203 had MCI,and the overall prevalence was 11.6%.Among them,the prevalence in ≥75 years old subjects(15.7%)was higher than that in 75 years old subjects(8.3%);the prevalence in the illiterate subjects(17.5%)was high than that in the literate subjects(7.2%);and the prevalence in the rural subjects(7.2%)was higher than that in the urban subjects(8.7%).There were significant differences among them(P=0.000 all).Although the incidence in females(12.3%)was higher than that in males(10.8%),and the aged people without spouses(13.7%)was higher than that who had spouses(10.6%),but there were no significant differences.②Only stroke had effect on the incidence of MCI in patients with the history of hypertension,diabetes mellitus,coronary artery disease and stroke(χ2 =18.853,P=0.000).Hypertension,coronary artery disease and diabetes mellitus had no significant effects on the incidence of MCI in the different age and sex groups(P0.05);While that stroke increased the incidence of MCI in the populations of old male(χ2=16.858,P=0.000),female(χ2=4.531,P=0.045)and 75 years old subjects(χ2=33.024,P=0.000).③With the increased coexistent diseases such as hypertension,diabetes mellitus,coronary artery disease and stroke(0,1 and ≥2 diseases),the incidence of MCI was also increased in the populations of male(χ2=11.119,P=0.004)and 75 years old persons(χ2=6.117,P=0.047).④ The multiple logistic regression analysis showed that stroke(OR:2.134,95% CI,1.459-3.120),living in countryside(OR:2.084,95% CI,1.502-2.893),≥75 years old(OR:1.853,95% CI,1.342-2.559)and illiterate(OR:2.178,95% CI,1.517-3.128)were the independent risk factors for MCI.Conclusion Stroke is an independent risk factor for MCI in old populations.Prevention of stroke is more significant for preventing dementia in the 75-year-old population and the aged males.