随着人的年龄增长，使得人们患有老年痴呆的机率越来越大，研究发现，得老年痴呆的主要因素是受载脂蛋白Ee4等位基因的影响。这种基因的存在会使人的认知功能下降，影响脑部的正常运转，从而增加了患老年痴呆的风险。

　　有没有什么办法可以预防呢?其实最简单有效的办法就是多运动。运动可以减少大脑中淀粉样蛋白的含量，从而大大降低了载脂蛋白Ee4等位基因对大脑的影响，多多进行运动锻炼对人的身心都有好处。

　　A new study finds that an active lifestyle may help protect against Alzheimer's-related brain changes in people who have a well-known genetic risk factor. This factor is the e4 allele (version) of the apolipoprotein E (APOE) gene.

　　"The presence of an APOE e4 allele is the most established genetic risk factor for Alzheimer disease, with a higher percentage of individuals with Alzheimer's disease having an e4 allele in comparison with the general population," the authors write in the article published online Jan. 9 in the journal Archives of Neurology. It's been suggested that the presence or absence of this gene variant might affect the relationship "between lifestyle factors such as exercise engagement and risk of cognitive decline and dementia," added researcher Denise Head and colleagues at Washington University, St. Louis.

　　They examined the association between exercise and amyloid deposits in the brain among 201 cognitively normal patients, ages 45 to 88, with and without the APOE e4 allele.

　　Deposits of amyloid protein in the brain have long been associated with Alzheimer's disease.

　　Patients with an active lifestyle had less cerebral amyloid deposition than those with a sedentary lifestyle, the study found.

　　The researchers conclude that the presence of the APOE e4 gene "is associated with increased risk of cognitive decline and elevated amyloid deposition." But they add that, "exercise engagement has been associated with reduced risk of cognitive decline and lower levels of amyloid deposition."

　　"In summary, our findings suggest that exercise at levels recommended by the AHA [American Heart Association] may be particularly beneficial in reducing the risk of brain amyloid deposition in cognitively normal e4-positive individuals," they concluded.