Association of olfactory function with the intensity of self-reported physical activity in adults with type 1 diabetes.

INTRODUCTION    Olfactory function is impaired in patients with type 1 diabetes and can be recognized as a form of diabetic neuropathy. Physical activity has various beneficial effects on type 1 diabetes. OBJECTIVES    The aim of this study was to assess a relation between physical activity and olfactory function in patients with type 1 diabetes. PATIENTS AND METHODS    We enrolled 120 patients with type 1 diabetes referred to an outpatient diabetes clinic. Patients with diabetes duration of less than 5 years, age above 65 years, concomitant diabetic ketoacidosis, and those using drugs affecting nasal mucosa were excluded. The final study sample included 90 patients. A control group comprised 22 healthy participants. Olfactory function was assessed using 12 odor‑emitting apens called Sniffin' Sticks. Physical activity was measured using the short version of the International Physical Activity Questionnaire (IPAQ‑SF). RESULTS    There was a significant difference in the occurrence of hyposmia between diabetic patients and healthy controls (70.0% vs 45.5%, respectively; P = 0.03). There were no significant differences in IPAQ‑SF results between the groups. Moreover, IPAQ‑SF results correlated positively with olfactory test scores (r = 0.25; P = 0.02) and negatively with age. Additionally, patients with retinopathy and autonomic neuropathy obtained lower IPAQ‑SF scores than patients without those complications. A stepwise multivariable linear regression analysis indicated IPAQ scores, body mass index, and peripheral neuropathy as predictors of the olfactory test score (R = 0.2).  CONCLUSIONS    Our study confirms the beneficial role of physical activity in type 1 diabetes within the structures of the central nervous system.