Jalali MM, et al. - In this cross-sectional study involving 66 males and 38 females, researchers examined the olfactory function between different subtypes of Parkinson disease (PD) and the effect of sex on smell identification test. Iran-smell identification test was used in this analysis. Using a Hoehn and Yahr (H&Y) scale, PD severity was determined. According to results, postural instability and gait difficulty were the most common PD subtype. In 44.6 and 19.6% of participants, respectively, severe hyposmia and anosmia were found. Compared with men, women had a higher score in olfactory function. The findings verified that PD is heterogeneous and the capacity to identify odor in these patients is significantly variable. More olfactory impairment was observed in tremor-dominant Parkinson disease and individuals with higher H&Y stage. In order to characterize the temporal relationship of olfactory dysfunction with PD, future studies with repeated measurements of different aspects of smell function were recommended.