Olfactory dysfunction and biological aging in NHANES 2013–2014: Archival deposit

Post-hoc archival deposit for the manuscript "Moderate-to-severe olfactory dysfunction marks accelerated phenotypic aging in U.S. adults" (Olcan 2026, submitted to Nature Aging). This deposit archives the manuscript, supplementary appendices, and methodological documentation accompanying a cross-sectional and prospective analysis of NHANES 2013-2014 (N = 3,519 adults aged ≥ 40; mortality follow-up through 2019). The MIT-licensed analytic pipeline is archived separately at Zenodo (DOI: 10.5281/zenodo.20059714). Note: This is a POST-HOC ARCHIVAL DEPOSIT, not a pre-registration. The author has been working with NHANES 2013-2014 data throughout the analytic process. A separate OSF project containing a true pre-registration of the planned external replication in non-NHANES cohorts (ARIC, Health ABC, BOSS) is filed prior to investigator access to those replication-cohort data. Headline findings: OD ≥4 of 8 odors incorrectly identified on the Pocket Smell Test was associated with +2.48 years of phenotypic aging acceleration (95% CI: +0.79, +4.16; p = 0.0039) and HR = 1.76 (95% CI: 1.32-2.34) for all-cause mortality, with 69.1% of the cross-sectional effect mediated through routine biomarker domains (renal, inflammation, hepatic, metabolic). Decision curve analysis showed negative net benefit at clinically actionable thresholds; OD ≥4 is therefore best interpreted as a biological-aging research signal rather than a clinical risk-stratification adjunct, pending external replication.