Therefore, in this study, we divided participants into CMD-free, single CMD, and CMD multimorbidity groups based on CMD status and then performed (1) the multivariable linear regression (MLR) models to investigate the associations of single CMDs and CMD multimorbidity with CSF AD biomarkers in cognitively intact participants; (2) stratified analyses by age, sex, and APOE ɛ4 status; and (3) sensitivity analyses to determine whether the conclusions were robust and which specific CMD combinations had associations with CSF AD biomarkers. The gene discussed is APOE; the disease is Alzheimer disease.