GFAP and dementia: To test this, we (1) evaluated the association between PEF and circulating levels of AD biomarkers (Aβ 42/40 ratio, p-Tau 181, NfL, and GFAP) and, (2) investigated the role of AD biomarkers mediating the association between impaired lung function (ILF) and risk of dementia in a nationally representative sample of older adults in the Health and Retirement Study (HRS).