Min JY, et al. - Researchers assessed if smell dysfunction was related to biomarkers associated with diabetes mellitus (DM), including fasting blood glucose, glycohemoglobin, serum insulin, and homeostasis model assessment of insulin sensitivity (HOMA-IR), in older U.S. adults. A significant association was revealed between smell dysfunction and severe insulin resistance in these adults. Authors noted that there could be a mechanistic link between insulin resistance and loss of smell function.

Methods

• Experts studied the data from 9,678 older adults who participated in the 2013 to 2014 National Health and Nutrition Examination Survey.
• For assessing smell, the 6-item, self-administered scratch-and-sniff smell test (Sensonics, Inc., Haddon Heights, NJ) was used.
• They defined smell dysfunction as the condition with an odor identification score of ≤ 5.

Results

• Among the 978 participants, 20% (n = 193) were described as having smell dysfunction.
• Compared to those in the lowest HOMA-IR quintile, participants in the highest HOMA-IR quintile had approximately 2-fold increased odds (odds ratio = 2.25; 95% confidence interval: 1.25–4.05) of smell dysfunction, after adjustment for potential confounding variables.
• The quintiles for fasting blood glucose, glycohemoglobin (HbA1c), or serum insulin levels had no association with the odds of smell dysfunction.