Characteristics of higher depressive tendency in the patients with olfactory disorder.

OBJECTIVE: Most patients with olfactory dysfunction experience stress and anxiety because of the inconvenience and changes caused by the loss of olfaction. However, psychological assessment is not performed routinely in patients with olfactory dysfunction, and the characteristics of these patients with psychological depression are unclear. METHODS: In this study, we used the Self-rating Depression Scale to evaluate the degree of depression in patients who visited our clinic with olfactory dysfunction and examine the characteristics of these patients with strong depressive tendencies. Patients who visited our clinic between April 2019 and March 2020 with complaints of olfactory dysfunction were included in the study. RESULTS: A total of 180 patients (79 male and 101 female) underwent olfactory examination and completed the Self-rating Depression Scale. Eighty-six and 94 patients were included in the low depression and high depression groups, respectively. Binomial logistic regression analysis showed significant positive associations of Self-rating Depression Scale scores with female sex and the presence of parosmia/phantosmia (p < 0.05). CONCLUSION: In our study, approximately half of the patients with olfactory dysfunction had depressive tendencies especially in female and parosmia/phantosmia patients. We believe that psychological assessments, such as that with the SDS, can help identify patients with olfactory dysfunction who may be at a greater risk of developing depression.

Efficacy of Normalising Serum Zinc Level for Patients with Olfactory Dysfunction and Zinc Deficiency.

INTRODUCTION: Zinc deficiency may worsen the severity of olfactory dysfunction; however, the relationship between serum zinc levels and therapeutic effects on olfactory dysfunction remains uncertain. This study investigated the relationship between normalising serum zinc levels and the therapeutic effects on olfactory dysfunction. METHODS: Forty-two patients diagnosed with post-infectious, post-traumatic, and idiopathic olfactory dysfunction, with serum zinc levels <70 µg/dL, were included in the study. All patients were treated with mecobalamin, tokishakuyakusan, and polaprezinc. The patients were divided into 2 groups: the zinc-normalised (≥70 µg/dL) and zinc-deficient (<70 µg/dL) groups, based on their post-treatment serum zinc levels. Olfactory test results were compared in each of the 2 groups. RESULTS: The patients were treated for a median of 133 days. The zinc-normalised group had significantly better results in all olfactory tests (detection/recognition thresholds of the T&T olfactometer, odour identification test (Open Essence), Visual Analogue Scale for olfactory dysfunction, and self-administered odour questionnaire). In contrast, only the self-administered odour questionnaire showed a significant improvement in the zinc-deficient group, with no significant differences observed in the other olfactory tests. When comparing the changes in the olfactory test scores between the 2 groups, significant differences were observed in the detection/recognition thresholds of the T&T olfactometer test and Open Essence results. CONCLUSION: These findings suggest that patients with olfactory dysfunction may have difficulty improving their olfactory function if they also have zinc deficiency. Furthermore, normalisation of zinc deficiency may contribute to the improvement of olfactory dysfunction with general treatment.

Relationship between the severity of olfactory dysfunction and serum zinc levels.

PURPOSE: Although the association between zinc deficiency and olfactory dysfunction is inconclusive, zinc deficiency causes apoptosis of the olfactory ensheathing cells which is involved in olfactory nerve turnover and axon regeneration, thereby suggesting a possible relationship. We investigated the relationship between serum zinc levels and olfactory function in patients with olfactory dysfunction. METHODS: Ninety patients who had been diagnosed with post-infectious, posttraumatic, drug-induced, neurological and idiopathic olfactory dysfunction were included. Patients were divided into zinc normal group and zinc deficiency groups according to three reference values for serum zinc levels (60, 65, 70 µg/dL). The results of olfactory tests and patient backgrounds were used to compare the differences between the two groups. RESULTS: There were significantly worse detection and recognition thresholds in the T&T olfactometer and Open Essence (odor identification test) results in the zinc deficiency group (< 60 µg/dL). In addition, significant correlations between olfactory tests (detection/recognition thresholds in the T&T olfactometer and Open Essence results) and serum zinc levels < 65 µg/dL were observed. The zinc deficiency group < 70 µg/dL with idiopathic olfactory dysfunction had significantly worse olfactory tests (detection/recognition thresholds in the T&T olfactometer and Open Essence). In addition, there was a significant correlation between the detection/recognition thresholds in the T&T olfactometer and serum zinc levels in idiopathic olfactory dysfunction. CONCLUSIONS: Our findings suggest that zinc deficiency may exacerbate the severity of olfactory dysfunction. Furthermore, idiopathic olfactory dysfunction may be partly caused by zinc deficiency.