The related factors to cognitive impairment among community-dwelling aged with mild cognitive impairment

Objective To explore the related factors to cognitive impairment among community-dwelling aged population with mild cognitive impairment（MCI）. Methods In this nested case-control study, a two-year follow-up program was conducted among 600 subjects with MCI. According to the changes and trends of cognitive function, 114 pairs of cognitive impairment subjects and control subjects were identified，matched with sex, age and educational level. Cox regression model of survival analysis was applied to analyze the related factors. Results Univariate and multivariate cox regression analysis revealed that risk factors were physical labour（OR=1.949,95%CI：1.041-3.637），smoking（OR=2.062,95%CI：1.029-4.445），living alone（OR=2.254,95%CI：1.029-4.937），higher level of blood glucose（OR=3.584,95%CI：1.891-6.791）, higher serum cholesterol（OR=2.204,95%CI：1.137-4.275），lower level of serum estrogen（OR=1.946,95%CI：1.087-3.411），hypertension（OR=3.951,95%CI:1.822-4.637），diabete（OR= 3.016,95%CI:1.886-4.157），hyperlipemia（OR=4.061,95%CI:1.724-9.568），cerebral thrombosis（OR= 2.347,95%CI:1.329-4.533），cerebral hemorrhage（OR=2.668,95%CI：1.579-4.802），higher SBP（OR=2.208,95%CI:1.343-3.629），ApoEe4 carrier（OR=2.717,95%CI：1.084-6.743），ApoEe4 carrier* serum cholesterol（OR=1.626, 95%CI:1.011-2.618). The protective factors were reading newspaper(OR=0.203, 95%CI:0.112-0.411), doing household duties frequently(OR=0.249, 95%CI：0.135-0.528), extroversion character(OR=0.544, 95%CI:0.327-0.938). Conclusions The risk factors for cognitive impairment may be physical labour, smoking, living alone，higher SBP, higher level of blood glucose and cholesterol, and lower level of serum estrogen，ApoEe4 carrier，hypertension, diabete, hyperlipemia, cerebrovascular disease. While reading newspaper，doing household duties frequently and extroversion character may be protective factors. Key words: Aged; Cognition; Factor analysis，statistical; Risk factors