Age-related decrease of odorant sensitivity for a selection of nine diverse molecules

The ability to smell is known to decrease with age. Still, several studies demonstrate that age-related deterioration is not the inevitable fate of each individual but rather depends on "successful aging" and odorant properties. Based on these notions, in the present prospective study, we aimed to investigate odor thresholds in younger and older adults in response to an extended list of various odorants.

In 58 participants (31% ≥ 50 years old), we assessed thresholds for nine odorants.

General Linear Mixed Model (GLMM) revealed that, independently of the odor context, younger adults had higher odor sensitivity compared to older ones. Furthermore, while molecular weight did not differentiate thresholds of older and younger adults, it impacted odor thresholds regardless of age, with higher sensitivity noted for lightweight molecules.

In conclusion, based on the present findings, odor thresholds decrease with age, with a pronounced effect for molecules with higher weight. Previous studies suggest that the decline in olfactory function is more significant for certain molecules. However, the current results indicate that this may be an odorant-specific phenomenon, as we did not observe this behavior in our study, which included a selection of nine diverse molecules.