Pre-registered analysis plan for external replication of olfactory dysfunction → biological aging and mortality (ARIC, Health ABC, BOSS)

This is the underlying project supporting an OSF Pre-Registration for the planned external replication of Olcan (2026) "Moderate-to-severe olfactory dysfunction marks accelerated phenotypic aging in U.S. adults" (Nature Aging, in submission). The pre-registration specifies the analytic protocol for replicating the discovery findings in three U.S.-based cohorts: ARIC (Atherosclerosis Risk in Communities), Health ABC (Health, Aging, and Body Composition Study), and BOSS (Beaver Dam Offspring Study). All three have measured olfactory examinations and prospective mortality follow-up. CRITICAL INTEGRITY DECLARATION: As of the pre-registration date, the author has NOT applied for, requested, or received access to any replication-cohort mortality data. Pre-registration is filed prior to investigator access in accordance with standard pre-registration practice. The replication analyses outlined have not been conducted and will be executed only after this pre-registration is published and after the author obtains formal Data Use Agreements with the relevant cohort coordinating centers. The discovery cohort (NHANES 2013-2014) is publicly available without restriction and has been fully analyzed; this pre-registration applies only to the planned replication in non-NHANES cohorts. Companion deposits: - Discovery code (Zenodo, MIT-licensed): https://doi.org/10.5281/zenodo.20059714 - Discovery archival deposit (OSF, post-hoc): https://doi.org/10.17605/OSF.IO/7Y5FU