Sex and Gender Differences in Parkinson's Disease

Acupuncture Effect on Reaction-Time Changes in Parkinson's Disease Patients-Case Study Series

Background: Parkinson's Disease (PD) is a progressive neurodegenerative condition associated with deficit in reaction time which can lead to falls, resulting in limited independence, diminished quality of life, heightened rates of institutionalization and increased healthcare costs. We aimed to examine the effects of an acupuncture protocol in motor time response after an auditory stimulus. Methods: This study employed a case series design. Reaction time to exposed rhythmic and random auditory stimuli outcomes were evaluated at six different moments over a month-long acupuncture treatment protocol using the MP 36 system from Biopac Systems. Results: We observed a tendency to have more pronounced improvements in the time response in the more affected side of the body compared with the contralateral one. Patients tended to show better values of response to random auditory stimuli compared to rhythmic auditory ones. We also observed a tendency to obtain better results when considering the accumulative effects of the acupuncture protocol. Conclusions: Our findings indicated a possible role of reaction time as a sensitive and useful tool for motor function assessment in PD patients. Also, from our results, we concluded that the acupuncture protocol used may lead to an improvement in efficacy of motor response after aleatory and rhythmic stimulus; we also found a tendency for a higher efficacy of acupuncture in random stimuli responses in the first stages of the disease. However, further in-depth research, including a statistical evaluation with a larger participant pool, is necessary to validate and confirm these promising results.

Attitudes and beliefs towards medication burden and deprescribing in Parkinson disease

BACKGROUND

Deprescribing of potentially inappropriate medications is recommended for older adults and may improve health outcomes and quality of life in persons living with Parkinson disease (PD). Patient attitudes, beliefs, and preferences play a crucial role in the success of deprescribing interventions. We aimed to examine the attitudes and beliefs about medication burden and deprescribing among persons living with PD.

METHODS

We administered a survey to participants of Fox Insight, a prospective longitudinal study of persons living with PD. The survey included the revised Patients' Attitudes Towards Deprescribing (rPATD) questionnaire and additional questions about adverse drug effects. We used logistic regression models to explore potential predictors of treatment dissatisfaction and willingness to deprescribe.

RESULTS

Of the 4945 rPATD respondents, 31.6% were dissatisfied with their current medications, and 87.1% would be willing to deprescribe medications. Male sex was associated with a greater willingness to deprescribe (adjusted odds ratio [aOR] 1.62, 95% confidence interval [CI] 1.37-1.93). A greater belief that the medication burden was high or that some medications were inappropriate was associated with treatment dissatisfaction (aORs 3.74, 95% CI 3.26-4.29 and 5.61, 95% CI 4.85-6.50), and more willingness to deprescribe (aORs 1.74, 95% CI 1.47-2.06 and 2.87, 95% CI 2.41-3.42). Cognitive impairment was the adverse drug effect participants were most concerned about when prescribed new medications to treat nonmotor symptoms.

CONCLUSIONS

Persons with PD are often dissatisfied with their overall medication load and are open to deprescribing. Medications that are associated with cognitive impairment might be prioritized targets for deprescribing interventions in this population.

Temporal trends in Parkinson's disease among older adults in the United States from 1999 to 2020: Retrospective analysis from CDC WONDER database

This retrospective study assessed the mortality trends related to Parkinson's Disease (PD) between 1999 and 2020. We assessed individuals aged 65 years and older and a total of 831,793 deaths were identified. Of these total number of deaths, place of death was accessible for 830,176 cases. Majority of the deaths occurred in nursing homes of long-term care facilities (367,633), followed by at home (212,886), medical facilities (165,450), other locations (44,506), and hospice (39,701). Analysis of age-adjusted mortality rates (AAMR) revealed an overall rise from 1999 to 2020, 88.9 to 119.6 per 100,000 population. AAMR showed an initial decline between 1999 and 2013, followed by a slight increase between 2013 and 2018 and then a significant rise from 2018 to 2020. Gender-based analysis showed a constantly higher AAMR for older men compared to older women. Variations in AAMR based on race and ethnicity revealed that Non-Hispanic White population had the highest AAMRs. Geographic disparities among states showed that Nebraska, Vermont, Minnesota, Utah, and Idaho had a significantly higher AAMR than Hawaii, Florida, Nevada. New York, and District of Columbia. Midwest region had a consistently higher AAMR followed by West, South, and Northeast. Additionally, nonmetropolitan areas had a higher AAMR than metropolitan areas. These findings offer valuable insights into mortality patterns related to PD among the elderly, highlighting the significance of incorporating demographic and geographic variables into public health planning and interventions.

17-β-estradiol potentiates the neurotrophic and neuroprotective effects mediated by the dopamine D3/acetylcholine nicotinic receptor heteromer in dopaminergic neurons

Dopaminergic neurons express a heteromer composed of the dopamine D3 receptor and the α4β2 nicotinic acetylcholine receptor, the D3R-nAChR heteromer, activated by both nicotine and dopamine D2 and D3 receptors agonists, such as quinpirole, and crucial for dopaminergic neuron homeostasis. We now report that D3R-nAChR heteromer activity is potentiated by 17-β-estradiol which acts as a positive allosteric modulator by binding a specific domain on the α4 subunit of the nicotinic receptor protomer. In mouse dopaminergic neurons, in fact, 17-β-estradiol significantly increased the ability of nicotine and quinpirole in promoting neuron dendritic remodeling and in protecting neurons against the accumulation of α-synuclein induced by deprivation of glucose, with a mechanism that does not involve the classical estrogen receptors. The potentiation induced by 17-β-estradiol required the D3R-nAChR heteromer since either nicotinic receptor or dopamine D3 receptor antagonists and interfering TAT-peptides, but not the estrogen receptor antagonist fulvestrant, specifically prevented 17-β-estradiol effects. Evidence of estrogens neuroprotection, mainly mediated by genomic mechanisms, have been provided, which is in line with epidemiological data reporting that females are less likely to develop Parkinson's Disease than males. Therefore, potentiation of D3R-nAChR heteromer activity may represent a further mechanism by which 17-β-estradiol reduces dopaminergic neuron vulnerability.

Sexual Orientation, Gender Identity, and Experiences During, Awareness of, and Attitudes Toward Research for People With Parkinson Disease

Background and Objectives

Presentation, progression, and treatment of Parkinson disease (PD) can differ based on sex and gender. However, knowledge on PD is limited by the characteristics of research participants, and most of the participants are men. In this study, we aimed to identify the attitudes toward and barriers to research participation for people with PD (PwP) based on their sexual orientation and gender identity.

Methods

Data were obtained from the Fox Insight on March 16, 2023, for PwP who completed the Attitudes and Beliefs Regarding Research and Genetic Testing for PD. Responses were compared between sexual and gender minorities (SGM) (n = 136), cisgender heterosexual women (n = 1,479), and cisgender heterosexual men (n = 1,445). Associations between age, socioeconomic variables, and the responses that differed between the groups were assessed with linear models.

Results

More than 68% of the participants were willing to participate in research; only 43.7% heard about research opportunities, and 52.3% knew where to find a study. Approximately 86.8% of the participants reported hearing about a study from their doctor would make them more likely to participate. A higher percentage of SGM were concerned about transportation and researchers not understanding or respecting their beliefs; a higher percentage of cisgender heterosexual women were concerned about transportation, data privacy, and their family's reaction to genetic results; and a higher percentage of cisgender heterosexual men were concerned about time required for research activities and complex forms. Age and socioeconomic variables were significantly associated with approach toward research that differed between the groups.

Discussion

PwP are willing to participate in research, and health care providers can facilitate their participation. Barriers to research participation related to sexual and gender identity exist and must be addressed to increase our understanding of PD in underrepresented populations.

The influence of sex on non-motor wearing-off in Parkinson's disease: A WORK-PD post-hoc study

INTRODUCTION

The wearing-off phenomenon is characterized by the recurrence of motor and non-motor symptoms of Parkinsonism during a period free from levodopa. It is a pivotal aspect marking the end of the pharmacological "honeymoon" period in Parkinson's disease (PD). A growing body of literature is connecting sex with the likelihood of developing fluctuations. We investigated such an association in a post-hoc analysis of the large WORK-PD study.

METHODS

WORK-PD analyzed the usability of the wearing-off questionnaire 19 (WOQ19) in clinical practice and included cross-sectional data on age, disease duration, time on levodopa, Hoehn and Yahr stage, and WOQ19 scores of 532 PD patients. In the present study, we selected patients with an exposure time to levodopa of at least 1 year.

RESULTS

A total of 380 patients were included. Women reported a higher number of wearing-off symptoms than men (6.09 ± 3.39 vs 4.96 ± 3.11, p = 0.0006). Sex groups also differed in non-motor symptoms (2 ± 1.9 vs 1.5 ± 1.5, p = 0.021), particularly behavioral wearing-off scores being higher in women (p < 0.001). The latter were primarily featured by anxiety-related phenomena. Finally, there was a significant interaction between behavioral symptoms, sex, and age at onset (df = 2, F = 9.79, p < 0.0001), whereas no such interaction was observed with levodopa exposure and motor impairment, unlike motor symptoms.

DISCUSSION

Women showed a greater propensity than men to experience wearing-off, particularly non-motor fluctuations on the anxiety spectrum. The latter may demonstrate a lesser reliance on dopamine compared to motor symptoms. This observation could be underpinned by biological variances between genders at the neurotransmitter level.

Unraveling sex differences in Parkinson's disease through explainable machine learning

Sex differences affect Parkinson's disease (PD) development and manifestation. Yet, current PD identification and treatments underuse these distinctions. Sex-focused PD literature often prioritizes prevalence rates over feature importance analysis. However, underlying aspects could make a feature significant for predicting PD, despite its score. Interactions between features require consideration, as do distinctions between scoring disparities and actual feature importance. For instance, a higher score in males for a certain feature doesn't necessarily mean it's less important for characterizing PD in females. This article proposes an explainable Machine Learning (ML) model to elucidate these underlying factors, emphasizing the importance of features. This insight could be critical for personalized medicine, suggesting the need to tailor data collection and analysis for males and females. The model identifies sex-specific differences in PD, aiding in predicting outcomes as "Healthy" or "Pathological". It adopts a system-level approach, integrating heterogeneous data - clinical, imaging, genetics, and demographics - to study new biomarkers for diagnosis. The explainable ML approach aids non-ML experts in understanding model decisions, fostering trust and facilitating interpretation of complex ML outcomes, thus enhancing usability and translational research. The ML model identifies muscle rigidity, autonomic and cognitive assessments, and family history as key contributors to PD diagnosis, with sex differences noted. The genetic variant SNCA-rs356181 may be more significant in characterizing PD in males. Interaction analysis reveals a greater occurrence of feature interplay among males compared to females. These disparities offer insights into PD pathophysiology and could guide the development of sex-specific diagnostic and therapeutic approaches.

Sex differences in the association between Body Mass Index and cognitive function in Parkinson disease: a cross-sectional study

Objective

This study utilized a binary logistic regression model to explore the relationship between Body Mass Index (BMI) and cognitive function in Parkinson's disease (PD) patients.

Methods

In this cross-sectional study, data were obtained from 1,005 Parkinson's patients enrolled in the Parkinson's Progression Markers Initiative (PPMI) from 2010 to 2023, including 378 females and 627 males. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) scale, and the correlation between BMI and cognitive function was determined using binary logistic regression.

Results

The median age of enrollment was 63.6 (56.2, 69.6) years old, including 378 (37.6%) females and 627 (62.4%) males. In the final adjusted model, a significant positive correlation was found between BMI and the prevalence of cognitive impairment in females (OR = 1.06, 95% CI = 1.01 ~ 1.12, p = 0.022), while no correlation was found in males (OR = 1.03, 95% CI = 0.99 ~ 1.08, p = 0.165). The results after categorizing BMI indicate that, among females, the risk of cognitive impairment increases for both groups with BMI ≥ 30 kg/m2 and those with 25 ≤ BMI < 30 kg/m2 compared to the reference group with BMI < 25 kg/m2, with a p for trend <0.001 indicating a stable and strong association between BMI and cognitive impairment in females. In males, the results were not significant. The trend of linear fitting was consistent with the above results.

Conclusion

In female Parkinson's patients, there is a positive correlation between BMI and cognitive impairment, while no correlation was found in male patients. This study provides new evidence of sex differences in the correlation between BMI and cognitive impairment among Parkinson's patients. The role of sex differences in the relationship between BMI and cognitive impairment should be considered in future research.

Global prevalence and incidence of Young Onset Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

There is a lack of enough evidence regarding the epidemiology of Young-onset Parkinson's disease (YOPD) which is needed by clinicians and healthcare policymakers.

AIM

Herein, in this systematic review and meta-analysis, we aimed to estimate the global prevalence and incidence rates of YOPD.

METHODS

We searched the literature in PubMed, Scopus, and Web of Science in May 2022. We included retrospective, prospective, cross-sectional observational population-based studies that reported the prevalence or incidence of PD in individuals younger than 40 years with known diagnostic criteria.

RESULTS

After two-step screening, 50 studies were eligible to be included in our study. The age-standardized prevalence of YOPD was 10.2 per 100,000 persons globally while it was 14.7 per 100,000 population in European countries. Age-standardized prevalence estimates for 5-year age bands showed that the YOPD prevalence estimates varied from 6.1 per 100,000 population in the group aged 20-24 to 16.1 per 100,000 population in the group aged 35-39. Also, the age-standardized incidence of YOPD was 1.3 per 100,000 person-years population worldwide and 1.2 per 100,000 person-years in the European population.

CONCLUSION

Based on this systematic review and meta-analysis, the overall prevalence of YOPD is 10.2 per 100,000 population, although estimates of the prevalence and incidence in low-income countries remain scarce. To improve monitoring and certain diagnoses of YOPD, healthcare providers and policymakers should be aware that much more effective tools are required.

Epidemiology of Parkinson's Disease: An Update

PURPOSE OF REVIEW

In recent decades, epidemiological understanding of Parkinson disease (PD) has evolved significantly. Major discoveries in genetics and large epidemiological investigations have provided a better understanding of the genetic, behavioral, and environmental factors that play a role in the pathogenesis and progression of PD. In this review, we provide an epidemiological update of PD with a particular focus on advances in the last five years of published literature.

RECENT FINDINGS

We include an overview of PD pathophysiology, followed by a detailed discussion of the known distribution of disease and varied determinants of disease. We describe investigations of risk factors for PD, and provide a critical summary of current knowledge, knowledge gaps, and both clinical and research implications. We emphasize the need to characterize the epidemiology of the disease in diverse populations. Despite increasing understanding of PD epidemiology, recent paradigm shifts in the conceptualization of PD as a biological entity will also impact epidemiological research moving forward and guide further work in this field.

Risk of impairment in cognitive instrumental activities of daily living for sexual and gender minority adults with reported Parkinson's disease

Objective: To investigate the risk of impairment in cognitive instrumental activities of daily living (IADL) for people with Parkinson's (PwP) identifying as sexual and/or gender minorities (SGM). Method: Data were obtained from Fox Insight, an online, longitudinal study with self/informant-report questionnaires from PwP and people without Parkinson's. Groups consisted of PwP without cognitive IADL impairment at baseline, identifying as (1) SGM with female sex assigned at birth (SGM-F, n = 75); (2) cisgender, heterosexual with female sex assigned at birth (CH-F, n = 2046); (3) SGM with male sex assigned at birth (SGM-M, n = 84); (4) cisgender, heterosexual with male sex assigned at birth (CH-M, n = 2056). Impairment in cognitive IADL was based on Penn Parkinson's Daily Activities Questionnaire-15 (PDAQ-15). Group differences for PDAQ-15 and impairment likelihood during follow-up were assessed with unadjusted models and adjusting for variables that differed between the groups. Results: SGM-F were the youngest at Parkinson's diagnosis; SGM-M had the lowest PDAQ-15 at baseline (p ≤ .014 for all). Scores declined more for males than females in unadjusted and adjusted models (p < .001 for both). In unadjusted models, SGM-M had a higher impairment risk than PwP identifying as cisgender and heterosexual (p ≤ .018). In adjusted models, females had a lower impairment risk than males (p < .001). Age, education, and discrimination level were significant moderators (p < .001 for all). Conclusions: SGM-M can be at a higher risk for impairment in cognitive IADL, associated with social determinants. Female sex assigned at birth may be associated with a lower level of impairment risk, although this advantage can disappear with social determinants.

Neurological care for LGBT+ people

Sexual and gender minority (LGBT+) people face unique health disparities that must be considered by health-care providers to ensure equitable and inclusive care. Although traditionally LGBT+ health has not been integrated into neurology training, sexual orientation and gender identity have direct relevance to neurological health, driven by both systemic and interpersonal factors. In this Review, we summarize the evidence for associations between sexual orientation and gender identity with the prevalence and outcomes of various neurological conditions, including neurodegenerative diseases, epilepsy, stroke and neurodevelopmental disorders, among others. We describe important clinical considerations pertaining to LGBT+ people and recommend language and practices to promote inclusive care, as well as highlight gaps in need of further research and possible strategies to minimize these, including systematic collection of sexual orientation and gender identity and use of inclusive language.

Quantification of Circulating Cell-Free DNA in Idiopathic Parkinson's Disease Patients

Parkinson's disease (PD) is one of the most common neurodegenerative disorders globally and leads to an excessive loss of dopaminergic neurons in the substantia nigra of the brain. Circulating cell-free DNA (ccf-DNA) are double-stranded DNA fragments of different sizes and origins that are released into the serum and cerebrospinal fluid (CSF) due to cell death (i.e., necrosis and apoptosis) or are actively released by viable cells via exocytosis and NETosis. Using droplet digital polymerase chain reaction (ddPCR), we comprehensively analyzed and distinguished circulating cell-free mitochondrial DNA (ccf mtDNA) and circulating cell-free nuclear DNA (ccfDNA) in the serum and CSF of PD and control patients. The quantitative analysis of serum ccf-DNA in PD patients demonstrated a significant increase in ccf mtDNA and ccfDNA compared to that in healthy control patients and a significantly higher copy of ccf mtDNA when compared to ccfDNA. Next, the serum ccf mtDNA levels significantly increased in male PD patients compared to those in healthy male controls. Furthermore, CSF ccf mtDNA in PD patients increased significantly compared to ccfDNA, and ccf mtDNA decreased in PD patients more than it did in healthy controls. These decreases were not statistically significant but were in agreement with previous data. Interestingly, ccf mtDNA increased in healthy control patients in both serum and CSF as compared to ccfDNA. The small sample size of serum and CSF were the main limitations of this study. To the best of our knowledge, this is the first comprehensive study on serum and CSF of PD patients using ddPCR to indicate the distribution of the copy number of ccf mtDNA as well as ccfDNA. If validated, we suggest that ccf mtDNA has greater potential than ccfDNA to lead the development of novel treatments for PD patients.

Animal Approaches to Studying Risk Factors for Parkinson's Disease: A Narrative Review

Despite recent efforts to search for biomarkers for the pre-symptomatic diagnosis of Parkinson's disease (PD), the presence of risk factors, prodromal signs, and family history still support the classification of individuals at risk for this disease. Human epidemiological studies are useful in this search but fail to provide causality. The study of well-known risk factors for PD in animal models can help elucidate mechanisms related to the disease's etiology and contribute to future prevention or treatment approaches. This narrative review aims to discuss animal studies that investigated four of the main risk factors and/or prodromal signs related to PD: advanced age, male sex, sleep alterations, and depression. Different databases were used to search the studies, which were included based on their relevance to the topic. Although still in a reduced number, such studies are of great relevance in the search for evidence that leads to a possible early diagnosis and improvements in methods of prevention and treatment.

Gender discrepancies and differences in motor and non-motor symptoms, cognition, and psychological outcomes in the treatment of Parkinson's disease with subthalamic deep brain stimulation

Available data suggest that there may be gender differences in the effect of STN-DBS in the treatment of Parkinson's disease (PD). The aim of this study was to review data on gender discrepancies and gender differences in clinical outcomes in PD patients treated with deep brain stimulation of the subthalamic nucleus (STN-DBS). Included were original studies that specifically examined gender discrepancies or gender differences in PD patients with STN-DBS. Men receive more DBS than women, for various indications. The decision-making process for DBS in women compared to men is more influenced by personal preferences and external factors. Motor symptoms improve in both genders, but bradykinesia improves more in men. The postoperative reduction of the levodopa equivalent daily dose seems to be more pronounced in men. Men show more cognitive deterioration and less improvement than women after STN-DBS. Women show more depressive symptoms before surgery, but they improve similarly to men. Men show more improvement in impulsivity and less decrease in impulsive behaviour symptoms than women. Anxiety and personality traits remain unchanged in both genders. Voice quality improves more in men and deteriorates less often than in women. Men gain fat-free mass and fat mass, but women only gain fat mass. Regarding sexual function the evidence is inconsistent. More urinary symptoms improve in women than in men. Pain and restless leg syndrome seems to improve more in men. Regarding quality of life, the evidence seems to be inconsistent, and activities of daily living seems to improve in both genders. Better prospective controlled studies, focusing directly on gender differences in PD patients treated with STN-DBS, are needed to better explain gender differences in STN-DBS for PD.

Mortality and causes of death in patients with Parkinson's disease: a nationwide population-based cohort study

Objective

Parkinson's disease (PD) is a neurodegenerative disease involving multiple systems that can affect mortality. This study aimed to compare all-cause and cause-specific mortality between people with PD and without PD.

Methods

This population-based prospective cohort study is based on Korean National Health Insurance Service data. The primary outcome was the hazard ratio (HR) of all-cause and cause-specific mortality for PD from 2010 to 2019. Cox proportional hazards regression was applied to calculate HRs under crude and three adjusted models with epidemiologic variables.

Results

A total of 8,220 PD patients and 41,100 age- and sex-matched controls without PD were registered. Ten-year mortality was 47.9% in PD patients and 20.3% in non-PD controls. The mortality rate was higher among older and male participants. The leading cause of death in PD was nervous system diseases (38.73%), and 97.1% of those were extrapyramidal and movement disorders, followed by circulatory diseases (15.33%), respiratory diseases (12.56%), and neoplasms (9.7%). PD contributed to an increased risk of all-cause death with an HR of 2.96 (95% CI = 2.84-3.08). HRs of death for PD were 3.07 (95% CI = 2.74-3.45) from respiratory diseases, 1.93 (95% CI = 1.75-2.13) from circulatory diseases, 2.35 (95% CI = 2.00-2.77) from external causes, and 2.69 (95% CI = 2.10-3.43) from infectious diseases.

Conclusion

These results showed that PD was related to a higher risk of mortality in all ages and sexes. The leading causes of death in PD were nervous, circulatory, respiratory, infectious diseases, and external causes.