Evaluating the Relationship Between Olfactory Function and Loneliness in Community-Dwelling Individuals: A Cross-sectional Study

Background Olfactory dysfunction (OD) has been reported to impact social interactions. However, the relationship between OD and loneliness has received little attention. The purpose of this study was to determine the association between OD and loneliness, controlling for patient factors. Methods Subjects without otolaryngic complaints were enrolled and olfactory function was assessed using: Sniffin' Sticks test to measure threshold, discrimination and identification (TDI), Questionnaire of Olfactory Disorders Negative Statements (QOD-NS) and 9 - item Olfactory-Visual Analogue Scale (VAS). Loneliness was assessed using the De Jong Gierveld (DJG) and University of California Los Angeles (UCLA) loneliness scales. Bivariate analysis was performed followed by regression analysis, controlling for confounders. Results In total, 221 subjects were included with a mean age of 50.5 years (range 20 to 93), 133 (60.2%) females and 161 (72.9%) white. Mean TDI score was 29.3 (7.0) and 49.5% of the cohort was dysosmic. Using DJG, 36.4% of the cohort were classified as lonely, whereas 35.0% were lonely using UCLA. Olfactory measures were significantly associated with DJG, including TDI (beta = -0.03, p = 0.050), olfactory discrimination (beta = -0.111, p = 0.005), QOD-NS (beta = 0.058, p < 0.001) and olfactory-VAS (beta = 0.032, p < 0.001). UCLA scores were significantly associated with QOD-NS (PR 1.061 [CI 1.018-1.107], p = 0.005) and olfactory-VAS scores (PR 1.027, [CI 1.007-1.049], p = 0.009). After controlling for confounders, the association between DJG and olfactory discrimination, as well as DJG and olfactory-VAS remained significant. Conclusions In this community-based sample of older adults, both OD and loneliness were common. Those subjects with worse olfactory function were more likely to report loneliness. Further research is necessary to establish causality, as well as explore the role of depression.