Objective  To systematically evaluate the role of blood lipid level in predicting the risk of Alzheimer′s disease (AD).

  Methods  We searched Chinese National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Database for Chinese Technical Periodicals (VIP), Pubmed, Web of Science, Springer, and Cocharne Library for literatures on the correlation between AD incidence and blood lipid level published in Chinese or English till June 2021 and supplementary manual tracing for some of the references was also conducted. Newcastle-Ottawa-Scale literature quality evaluation scale was adopted to evaluate the quality of the included studies. Statistical analyses were performed with RevMan5.3 software.

  Results  A total of 15 eligible studies were selected according to the inclusion and exclusion criteria, and the data on blood lipid level were collected from 1 435 healthy elderly people and 2 162 elderly people with AD. Meta-analysis showed that there was no significant difference in total cholesterol (TC) and triglyceride (TG) level between the AD sufferers and the healthy controls; low-density lipoprotein cholesterol (LDL-C) was significantly higher in the AD sufferers than that in the healthy controls (mean difference MD = 3.59, 95% confidence interval 95% CI: 0.98 – 6.21); while, high-density lipoprotein cholesterol (HDL-C) was significantly lower in the AD sufferers than that in the healthy controls (MD = – 3.47, 95% CI: – 5.94 – – 0.99).

  Conclusion  Higher LDL-C level but lower HDL-C level may indicate a higher risk of AD in older adults.