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Introduction: Olfactory dysfunction is suggested to be a clinical manifestation of central diabetic neuropathy. The aim of the study was to assess olfactory function in adult patients with type 1 diabetes. Materials and methods: A total of 106 patients with type 1 diabetes and 30 healthy subjects were included in the study. We evaluated the metabolic control of diabetes and the presence of chronic complications. Olfactory function was assessed with Sniffin' Sticks. Results: We found a negative correlation between olfactory identification scores and body mass index (Rs −0.2; p = 0.04) and triglycerides (Rs = −0.2; p = 0.04). We showed lower olfactory identification scores in neuropathy group versus non-neuropathy group [8 (interquartile range, 7-9) vs 10 (interquartile range, 9-11) points; p = 0.005]. In multivariate linear regression, impaired olfaction was independently associated with neuropathy (beta, −0.3; p = 0.005). In multivariate logistic regression, diabetes duration (odds ratio, 1.06; 95% confidence interval, 1.00-1.11; p = 0.04) and olfactory identification score (odds ratio, 0.61; 95% confidence interval, 0.43-0.85; p = 0.003) were independently associated with neuropathy. Conclusion: Olfactory dysfunction is observed in patients with type 1 diabetes and diabetic peripheral neuropathy.

Aim To investigate whether insulin resistance is a predictor for decreased olfactory function in adult type 1 diabetes patients (T1DM). Materials and Methods The following parameters were examined in the group of 113 T1DM participants: body mass index (BMI), waist‐hip ratio (WHR), TG/HDL ratio, glycated hemoglobin (HbA1c), visceral fat (VF) in body bioimpedance, specific calculators (eGDR, VAI). Bilateral olfactory test score (BOTS) was performed using 12‐odour‐tests from Sniffin' Sticks. Then participants were allocated to one of two groups: normosmia (10‐12 odours identified) or hyposmia/anosmia (0‐9 odours). The association between BOTS and insulin resistance indicators was analyzed using: Spearman's rank correlation, multivariate linear regression analysis, and receiver operating characteristic (ROC) curve. Results 49.6% participants were diagnosed with hyposmia/anosmia, median BOTS was 10. BOTS correlated significantly with: WHR, TG, VF index, TG/HDL ratio, VAI, and eGDR. In multivariate linear regression analysis higher WHR turned out to be statistically significant independent predictor of lower BOTS (β = −0.36; P = .005) after adjustment for age, sex, TG and peripheral neuropathy (R2 = 0.19; P = .0005). The ROC analysis indicated a WHR cut‐off of 0.92 [area under the ROC curve (AUC): 0.737; 95% confidence interval (CI): 0.647‐0.828, P < .0001] as the best among evaluated factors significantly affecting hyposmia/anosmia occurrence (sensitivity of this cut‐off 0.50 and specificity 0.86). Conclusions We have provided evidence of an association between lowered insulin sensitivity expressed in bioelectrical impedance analysis, anthropometrical (WHR), laboratory (TG/HDL ratio) measurements, specific calculators (eGDR, VAI) and deteriorated olfactory function.