Inability to Smell Peppermint Is Related to Cognitive Decline: A Prospective Community-Based Study.

BACKGROUND

A few studies have demonstrated the association of poorer olfactory identification (OI) with poorer cognition in population-based cohorts. None of them considered the outcome associated with the inability to smell a certain odor.

OBJECTIVE

To verify the hypothesis that at least one specific odor is associated with incident cognitive decline among older adults.

METHODS

In the Shanghai Aging Study, a sub-cohort of 948 dementia-free participants who had baseline OI measurements were prospectively followed for 5 years.

RESULTS

An inability to smell peppermint (β = -0.44, p < 0.001), rose (β = -0.14, p = 0.040), or coffee (β = -0.37, p = 0.002) was inversely related to the annual rate of change in the Mini Mental State Examination score, and an inability to smell peppermint was associated with a higher risk for incident dementia (hazard ratio 2.67, 95% CI 1.44-4.96) after adjustment for confounders.

CONCLUSION

Our study suggests that some odors, especially peppermint, might be considered as a potential predictor for dementia in older populations.