Correlates of olfactory impairment in middle-aged non-diabetic Caucasian subjects with stage I-II obesity.
PURPOSE
This study evaluates among middle-aged subjects with obesity the prevalence of olfactory impairment (OI) with respect to normative values and its correlation with body composition, cognition, sleep quality, and inflammation.


METHODS
In 60 (31 women, 29 men) volunteers with a body mass index ≥ 30 to ≤ 40 kg/m2, aged ≥ 50 to ≤ 70 years, we assessed olfaction by the Sniffin' Stick test. We measured anthropometrics, body composition and metabolic profiles and evaluated cognition by the MiniMental State Examination (MMSE) and sleep disturbances by the Insomnia Severity Index (ISI). Patients were classified into two groups according to a total olfactory score (odor Threshold, Discrimination, Identification, TDI) below or above the 25th percentile from age and gender-adjusted normative data.


RESULTS
Overall, 25 subjects (42%) had OI (TDI < 25th percentile). The largest differences between subjects with and without OI were observed in discrimination and identification scores, with a large overlap in olfactory threshold. Subjects with an abnormal TDI showed significantly higher fat mass index, ISI scores and urinary neopterin and lower MMSE scores than those without OI. By multivariable logistic regression, MMSE, ISI score and urinary neopterin were significantly associated to OI.


CONCLUSIONS
Among middle-aged subjects with stage I and II obesity, OI is highly prevalent and is independently associated with poor self-reported sleep quality, lower cognition scores and higher levels of the inflammatory marker neopterin.
['Campolo|Jonica|J|http://orcid.org/0000-0002-1711-6216', 'Corradi|Ettore|E|', 'Rizzardi|Alice|A|', 'Parolini|Marina|M|', 'Dellanoce|Cinzia|C|', 'Di Guglielmo|Maria Luisa|ML|', 'Tarlarini|Patrizia|P|', 'Cattaneo|Marina|M|', 'Trivella|Maria Giovanna|MG|', 'De Maria|Renata|R|']
D000368:Aged D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009765:Obesity D009812:Odorants D000857:Olfaction Disorders D012684:Sensory Thresholds D012903:Smell
Obesity Olfaction MiniMental state examination Sleep disturbances Neopterin