Anosmia and dysgeusia among COVID-19 patients are associated with low
levels of serum Glucagon-like peptide 1 (GLP-1)
Purpose: Anosmia and dysgeusia (AD) are common among COVID-19 patients.
These symptoms are not frequently associated with rhinorrhea or nasal
congestion and the underlying mechanism is unclear. Previous reports
suggested that Glucagon-like peptide-1 (GLP-1) signaling plays a role in
the modulation of olfaction and geusia. We aimed to assess the
correlation between GLP-1 and COVID-19-associated AD. Methods: Blood
samples obtained from COVID-19 patients with and without AD were tested
for serum GLP-1 levels using enzyme-linked immunosorbent assay (ELISA).
A second control group comprised of COVID-19-negative volunteers.
Results: Forty-nine subjects were included in the study. Nineteen were
positive for COVID-19. Of the 19 patients, ten had AD and nine declined
such complaints. Age and basic metabolic rate were similar among all
study groups. Serum GLP-1 levels were significantly lower among patients
with AD as compared with patients without AD and COVID-19-negative
individuals (1820 pg/ml vs 3536 pg/ml vs 3014 pg/ml, respectively,
p<0.02). Conclusion: COVID-19 patients who reported of AD had
lower serum levels of GLP-1 as compared with those lacking AD symptoms
and COVID-19-negative individuals. These results suggest that GLP-1 may
be involved in the pathogenesis of AD. However, further larger scale
studies should corroborate our findings