en Cellular and molecular Neuroscience Cellular and molecular Neuroscience Original Original <div style="text-align: justify;"><strong>Introduction</strong>: Parkinson&rsquo;s disease (PD) is a common neurodegenerative disease whose motor and non-motor complications significantly affect a person&rsquo;s quality of life (QoL). This study aimed to investigate the QoL of these patients using the PD questionnaire (PDQ)-39 and identify the prognostic factors associated with their QoL.<br> <strong>Methods</strong>: In this case-control study, the QoL of two groups (211 controls and 211 cases) was investigated and compared using the PDQ-39 questionnaire. Prognostic factors associated with QoL were determined using multivariate logistic regression analyses.<br> <strong>Results</strong>: Several 422 patients with a mean age of 59.8&plusmn;13.7 years were included in the study. The mean PDQ-39 score in the case group was significantly higher in all subscales, except for social support, compared to the control group. The mean score of PDQ-39 was significantly higher in the patients with non-deep brain stimulation (DBS) (53.9&plusmn;21.1 (than those with DBS (42.22&plusmn;18.1), especially in the sub-scales of mobility, activities of daily living, cognition, and communication. As the stage of the disease increased, the mean PDQ-39 score in these patients increased significantly. The results of the multivariate analysis showed that sex, patient age, smoking, education level, duration of disease, patient stage, and intervention with DBS were significantly related to patients&rsquo; QoL (P<0.05).&nbsp;<br> <strong>Conclusion</strong>: This study highlights the significant impact of DBS on PD patients&rsquo; QoL, especially in sub-scales of mobility, daily activities, emotional well-being, and cognition. Moreover, identifying the main prognostic factors of QoL (sex, age, smoking status, educational level, disease duration, and stage) can lead to avenues for improving the lives of these patients.</div> Parkinson, Quality of life (QoL), Parkinson’s disease questionnaire (PDQ)-39, Prognostic factors 667 676 http://bcn.iums.ac.ir/browse.php?a_code=A-10-6859-1&slc_lang=en&sid=1 Aida Moarrefzadeh Enshroud_man@yahoo.com 13700319475328460054330 13700319475328460054330 No Department of Psychology, Faculty of Humanities, Ahar Branch, Islamic Azad University, Ahar, Iran. Sadra Sarandili saa.sarandili@gmail.com 13700319475328460054331 0009-0001-0088-5094 No Department of Health Sciences, Curtin Medical School, Curtin University, Perth, Australia. Nogol Motamed-Gorji nogol_motamed96@yahoo.com 13700319475328460054332 13700319475328460054332 No Colorectal Research Center, Iran University of Medical Sciences, Tehran, Iran. Fatemeh Majdolashrafi fateme.majdolashrafi1377@gmail.com 13700319475328460054333 13700319475328460054333 No Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Mansour Bahardoust mansourbahari93@gmail.com 13700319475328460054334 13700319475328460054334 No Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Safa Mousavi Smv.safaa@gmail.com 13700319475328460054335 0009-0003-9117-4603 No Department of Public Health, College of Health and Human Services, California State University, Fresno, United States. Neda Hashemi nedahashemi1363@yahoo.com 13700319475328460054336 13700319475328460054336 No Department of Perinatology, Endometriosis Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Arash Sarveazad Arashsarveazad@gmail.com 13700319475328460054337 13700319475328460054337 No Colorectal Research Center, Iran University of Medical Sciences, Tehran, Iran. Mohammadhossein Vazirizadeh-Mahabadi sepehrvaziri.zm@gmail.com 13700319475328460054338 13700319475328460054338 No Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran. Seyed Amirhassan Habibi habibisaiyedamir@yahoo.com 13700319475328460054339 13700319475328460054339 Yes Department of Movement Disorders, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.