the factors associated with olfactory dysfunction in patients with multiple sclerosis

Introduction: an impaired sense of smell has a remarkable impact on the quality of life. it is seen in a variety of neurodegenerative diseases such as parkinson disease. in this study, we assessed the olfactory function in patients with multiple sclerosis (ms) by sniff magnitude test (smt). methods: a cross-sectional study was conducted on 48 patients with ms. a questionnaire, including demographic and clinical variables, was completed for each patient. the smt was used for the evaluation of olfactory function. results: olfactory dysfunction was found in 14.6% of patients (8.3% hyposmia and 6.3% anosmia). older age, longer disease duration, higher hospital admission rate, lower minimental status examination score, and secondary progressive course of ms were significantly related to olfactory dysfunction. conclusion: secondary progressive ms and markers of advanced disease toward neurodegenerative phase (including older age, longer disease duration, and lower cognitive function) can be associated with olfactory dysfunction in ms patients.