[Risk factors and their interaction on cognitive impairment in the elderly in China: case-control study].

Objective: To investigate the association of apolipoprotein E (ApoE) genotype, sleep problem, olfaction problems, chronic constipation and their interactions on cognitive impairment in the elderly aged 60 and above. Methods: A stratified multi-stage cluster sampling was used in 6 provinces (autonomous administrative regions and municipalities) to select the sample. 1 300 cases with cognitive impairment and 2 600 controls without cognitive impairment were recruited and matched according to their age, gender and resident area in a 1∶2 case-control study. A total of 3 501 people were included after data cleaning. Chi-square test and conditional logistic regression model were used for univariate analysis, multivariate analysis and interaction analysis. Results: ApoE carrying ε4 genotypes, sleep problems, smell disorders, constipation is independent risk factors of cognitive impairment in the elderly (OR=1.44, 1.65, 2.26, 2.13, P<0.001). The additive interaction between ApoE genotype and olfaction change was statistically significant [AP=0.45(95%CI: 0.13- 0.77), S=2.37 (95%CI: 1.08-5.24)]. The interaction between other factors with cognitive impairment was not found to be statistically significant. The above results were adjusted for occupation, tea drinking, neighborhood interaction, social activities, physical exercise, reading books and newspapers, playing cards and mahjong, memory changes and hypertension, diabetes, stroke. Conclusions: ApoE genotype, sleep problems, olfaction problems, and chronic constipation are risk factors for cognitive impairment in people 60 and older. There is a synergistic interaction effect between ApoE genotype and olfaction problems on cognitive impairment in the elderly over 60 years old.目的： 探讨载脂蛋白E（ApoE）基因型、睡眠问题、嗅觉问题、长期便秘及其交互作用对≥60岁老年人认知异常的影响。 方法： 调查对象来自老年期重点疾病预防和干预项目试点调查，采用简易精神状况检查量表进行认知功能评定筛查出的1 300名认知功能异常者作为病例组，以该人群中非认知异常者作为对照组，按照年龄、性别和地区进行1∶2匹配。最后，经数据清理共1 167对病例对照组进入研究。采用χ(2)检验和条件logistic模型进行相应的单因素分析、多因素分析及交互作用分析。 结果： 分析均调整了职业、饮茶、邻里交往、社会活动、身体锻炼、读书看报、打牌玩麻将、记忆变化、高血压、糖尿病、脑卒中，结果发现ApoE-ε4基因型、睡眠问题、嗅觉问题、长期便秘是老年人认知异常的独立危险因素（OR值分别为1.44、1.65、2.26、2.13，P<0.001），ApoE基因型与嗅觉问题对认知异常的相加交互作用有统计学意义[AP=0.45（95%CI：0.13~0.77），S=2.37（95%CI：1.08~5.24）]。本研究模型未发现其他因素间的交互作用有统计学意义。 结论： ApoE基因型、睡眠问题、嗅觉问题、长期便秘是≥60岁老年人认知异常的危险因素。ApoE基因型与嗅觉变化对≥60岁老年人认知异常的影响存在协同交互作用。.