Abstract
Olfactory dysfunction is highly prevalent in the elderly population, severely affecting nutritional status, environmental safety perception, and quality of life, and is recognized as an early warning marker of neurodegenerative diseases. Compared with populations living at low altitudes, residents at high altitudes are chronically exposed to combined extreme environmental conditions including hypoxia, low temperature, and low humidity, which may lead to more complex and severe degenerative changes in the olfactory system. However, existing evidence remains fragmented, and a systematic synthesis is lacking. This narrative review aims to systematically integrate the epidemiological characteristics, pathophysiological mechanisms, diagnostic assessment tools, intervention strategies, and health risks associated with olfactory decline in elderly residents at high altitudes. Epidemiological evidence shows a significant negative correlation between altitude and olfactory function, and the effects of aging are substantially amplified under high-altitude conditions. The underlying mechanisms primarily involve chronic hypoxia interacting with aging and genetic susceptibility through damage to olfactory ensheathing cells, suppression of olfactory neurogenesis, and remodeling of synaptic plasticity in olfactory-related brain regions. Olfactory behavioral testing combined with functional magnetic resonance imaging and emerging biomarkers provides multidimensional tools for early diagnostic stratification. Although oxygen therapy, olfactory training, and environmental management have shown potential efficacy, evidence-based data specific to this population remain limited. The core value of this review lies in adopting an integrated perspective of "environment-aging" interactions to systematically elucidate the combined effects of high-altitude stress and age-related degenerative changes on the olfactory system, revealing the unique patterns and intervention targets for olfactory dysfunction in this vulnerable population. Future research urgently needs large-scale longitudinal cohort studies, establishment of altitude-specific normative olfactory assessment tools, and development of precision interventions targeting hypoxic injury to improve overall health outcomes in this population.