Genetic evidence for a causal relationship between 179 lipid species and cognitive function and alzheimer's disease:...

The public health burden of cognitive decline escalates with population aging. While lipid species alterations are associated with cognitive function and Alzheimer's disease (AD), causal evidence remains limited. We applied two-sample Mendelian randomization (TSMR) and Bayesian-weighted MR (BWMR) to investigate the causal effects of lipid species on cognitive function and to assess the bidirectional causal relationships between lipid species and AD. We analyzed genome-wide association study (GWAS) data from large-scale cohorts: AD (East African Development Bank [EADB], N = 487,511); cognitive function (UK Biobank, N = 20,346); and lipid species (THL Biobank, N = 7,174). Analyses were conducted using multiple MR methods, including inverse variance weighting (IVW), BWMR, MR-Egger regression, and false discovery rate (FDR) correction. Sensitivity analyses-MR-Egger intercept test, MR-Pleiotropy Residual Sum and Outlier (MR-PRESSO), Cochran's Q test, and leave-one-out analysis-were conducted to evaluate horizontal pleiotropy and heterogeneity. TSMR results identified 51 lipid species with causal associations for cognitive function and AD, among which 27 showed protective effects. Conversely, AD was found to influence 17 lipid species, with 14 exhibiting negative effects. These genetically supported findings highlight potential lipid-related targets for preventive and therapeutic interventions aimed at combating cognitive decline.