ASSOCIATION BETWEEN CORTISOL AND QUALITY OF LIFE IN PARKINSON'S DISEASE: MAPPING THE AVAILABLE EVIDENCE

Abstract

Parkinson's Disease (PD) is a progressive neurodegenerative disease that impacts, in addition to motor symptoms, the quality of life (QoL) of patients through non-motor symptoms such as anxiety, fatigue, and sleep disorders. Cortisol, a stress hormone, has been investigated as a biological marker linked to the subjective experience of PD, presenting complex relationships with QoL. This scoping review mapped the evidence on the association between cortisol measures and quality of life in people with PD, through the analysis of original studies that measured both variables simultaneously. We included three studies that demonstrated that altered cortisol levels, especially in salivary samples collected at specific times, are related to worse QoL related to non-motor symptoms such as fatigue and anxiety, with evidence of variations by sex and psychosocial influence between patients and caregivers. The findings highlight the need for standardization of cortisol collection and analysis protocols, as well as the multidimensional assessment of QoL in PD, for a better understanding of the mechanisms and support for future clinical interventions. Despite the limitations due to methodological heterogeneity and the small number of studies available, this synthesis contributes to identifying gaps and guiding further research at the interface between hormonal biomarkers and well-being in PD.