Longitudinal trajectories of olfactory abilities: What predicts old-age olfactory memory decline?

Olfactory deficits are common in old age and associated with adverse health outcomes. We aim to do a thorough investigation of predictors of olfactory memory decline in the normal elderly population. Predictors from the demographic, cognitive, clinical, genetic, and behavioral domains will be evaluated. For a subsample, neuroimaging and blood inflammatory markers will also be examined. An additional aim is to evaluate the uniqueness of olfactory memory relative to memory for other sensory information in aging.

We will use an existing database from a large Swedish population-based cohort – SNAC-K. Olfactory abilities, neuropsychological test performance, physical function, and medical health were repeatedly assessed across 12 years in people aged ≥ 60 years. With the large sample size and broad range of variables available, we will be able to assess predictors of incident olfactory dysfunction (i.e. performing below a clinical threshold), olfactory memory decline, and aging successfully in terms of olfactory abilities. Interaction effects between different predictors will also be examined. Previously, these questions have mainly been addressed with cross-sectional data.

The results will promote the understanding of the underlying causes of old-age olfactory impairment. This will have implications for how to design interventions to maintain olfactory function into old age.

This project is funded by the Swedish Research Council (VR).