Effect of family history, occupation and diet on the risk of Parkinson disease: A case-control study

Exploring Risk and Protective Factors in Parkinson's Disease

Understanding the risk and protective factors associated with Parkinson's disease (PD) is crucial for improving outcomes for patients, individuals at risk, healthcare providers, and healthcare systems. Studying these factors not only enhances our knowledge of the disease but also aids in developing effective prevention, management, and treatment strategies. This paper reviews the key risk and protective factors associated with PD, with a particular focus on the biological mechanisms underlying these factors. Risk factors include genetic mutations, racial predispositions, and environmental exposures, all of which contribute to an increased likelihood of developing PD or accelerating its progression. Conversely, protective factors, such as regular physical exercise, adherence to a Mediterranean diet, and higher urate levels, have the potential to reduce inflammation and support mitochondrial function, thereby mitigating the risk of disease. However, identifying and validating these factors presents significant challenges. These challenges include the absence of reliable biomarkers, intricate interactions between genetic and environmental components, and clinical heterogeneity observed in patients with PD. These barriers complicate the establishment of clear causal relationships and hinder the development of targeted preventive strategies. To overcome these challenges, we propose several solutions and recommendations. Understanding the mechanisms underlying risk factors may inform future research aimed at developing standardized and more accurate biomarkers for PD, facilitating earlier diagnosis and improved monitoring of disease progression. Additionally, we offer actionable recommendations for PD prevention and management tailored to healthy individuals, patients diagnosed with PD, and healthcare systems. These strategies aim to improve clinical outcomes, enhance the quality of life, and optimize healthcare delivery for PD.

The Polygenic Risk Score for Parkinson's Disease Is Associated with Becoming a Medical Doctor or Dentist

BACKGROUND/OBJECTIVES

Multiple independent studies indicate an association between the occupations of medical doctors and dentists and the risk of Parkinson's disease (PD). This study tried to evaluate the associations between a polygenic risk score (PRS) for Parkinson's disease (PD) and medical career (medical doctor/dentist).

METHODS

This population-based cross-sectional study used data from the UK Biobank. A total of 92,566 and 166,531 men and women aged 38-73 years, recruited between 2006 and 2010, were included in the analyses of job history and current job, respectively (separate samples). Odds risks for the jobs of medical doctors and dentists were estimated using logistic regression. A PRS of polymorphisms previously shown to predict PD best was constructed and associated with the job history of medical doctors/dentists in the first analysis and with current medical doctor/dentist jobs in the second analysis after regressing out confounding variables.

RESULTS

A high PD PRS was associated with employment as a medical doctor or dentist for both the 92,566 individuals with job history data, with an increase of 1 standardized deviation (p = 0.006), and current employment as medical doctors/dentists among the 166,531 individuals without job history data but with current job data. Furthermore, a higher PD PRS was associated with higher education in both samples.

CONCLUSIONS

These results suggest that PD has shared genetic routes with a propensity for higher education and becoming medical doctors/dentists.

An analysis of curative care expenditure for Parkinson's disease under different comorbidity conditions: an empirical study based on China

BACKGROUND

This study aims to evaluate the curative care expenditure (CCE) of Parkinson's disease (PD) under different comorbidity conditions to provide a reference basis for formulating health policies for PD.

METHODS

This study used a multi-stage stratified random sampling method to investigate 37,604 PD patients in 1,600 medical institutions in Sichuan, China, in 2019. Based on the System of Health Accounts 2011 (SHA2011), the scale of the CCE, financing schemes, institutional flows, and beneficiary groups of PD under different comorbidity conditions were calculated. Multiple linear regression model was used to analyze the factors influencing the hospitalization expenditure.

RESULTS

In 2019, the total CCE for PD in Sichuan was US$36.29 million, accounting for 0.11% of the province's total disease CCE and 0.005% of its gross domestic product (GDP) that year. Household out-of-pocket (OOP) payments (68.98% for outpatients and 42.26% for inpatients) and public financing schemes (30.69% for outpatients and 52.28% for inpatients) were the main sources of financing CCE. More than 80% of the CCE went to general hospitals, while less than 2% went to primary health-care institutions. As the comorbidity index increased, the CCE for PD exhibited an aging trend, with the low-, medium-, and high-comorbidity groups mainly concentrated in those in their fifties, those aged 60-79, and those over 80, respectively. The multiple linear regression analysis showed that the top three factors affecting hospitalization expenditure were the length of stay, surgery and institution level.

CONCLUSIONS

The CCE for PD is high, and individuals and families are the main bearers of health expenditures. It is recommended to optimize medical insurance policies, increase outpatient insurance coverage, and gradually increase the level of insurance benefits. Furthermore, it is necessary to explore multi-party collaboration to establish a diversified and multi-level medical security system for PD.

Parkinson disease therapy: current strategies and future research priorities

Parkinson disease (PD) is the fastest growing neurological disorder globally and poses substantial management challenges owing to progressive disability, emergence of levodopa-resistant symptoms, and treatment-related complications. In this Review, we examine the current state of research into PD therapies and outline future priorities for advancing our understanding and treatment of the disease. We identify two main research priorities for the coming years: first, slowing the progression of the disease through the integration of sensitive biomarkers and targeted biological therapies, and second, enhancing existing symptomatic treatments, encompassing surgical and infusion therapies, with the goal of postponing complications and improving long-term patient management. The path towards disease modification is impeded by the multifaceted pathophysiology and diverse mechanisms underlying PD. Ongoing studies are directed at α-synuclein aggregation, complemented by efforts to address specific pathways associated with the less common genetic forms of the disease. The success of these efforts relies on establishing robust end points, incorporating technology, and identifying reliable biomarkers for early diagnosis and continuous monitoring of disease progression. In the context of symptomatic treatment, the focus should shift towards refining existing approaches and fostering the development of novel therapeutic strategies that target levodopa-resistant symptoms and clinical manifestations that substantially impair quality of life.

Parkinson's families project: a UK-wide study of early onset and familial Parkinson's disease

The Parkinson's Families Project is a UK-wide study aimed at identifying genetic variation associated with familial and early-onset Parkinson's disease (PD). We recruited individuals with a clinical diagnosis of PD and age at motor symptom onset ≤45 years and/or a family history of PD in up to third-degree relatives. Where possible, we also recruited affected and unaffected relatives. We analysed DNA samples with a combination of single nucleotide polymorphism (SNP) array genotyping, multiplex ligation-dependent probe amplification (MLPA), and whole-genome sequencing (WGS). We investigated the association between identified pathogenic mutations and demographic and clinical factors such as age at motor symptom onset, family history, motor symptoms (MDS-UPDRS) and cognitive performance (MoCA). We performed baseline genetic analysis in 718 families, of which 205 had sporadic early-onset PD (sEOPD), 113 had familial early-onset PD (fEOPD), and 400 had late-onset familial PD (fLOPD). 69 (9.6%) of these families carried pathogenic variants in known monogenic PD-related genes. The rate of a molecular diagnosis increased to 28.1% in PD with motor onset ≤35 years. We identified pathogenic variants in LRRK2 in 4.2% of families, and biallelic pathogenic variants in PRKN in 3.6% of families. We also identified two families with SNCA duplications and three families with a pathogenic repeat expansion in ATXN2, as well as single families with pathogenic variants in VCP, PINK1, PNPLA6, PLA2G6, SPG7, GCH1, and RAB32. An additional 73 (10.2%) families were carriers of at least one pathogenic or risk GBA1 variant. Most early-onset and familial PD cases do not have a known genetic cause, indicating that there are likely to be further monogenic causes for PD.

Clinical Characteristics of Patients with De Novo Parkinson's Disease and a Positive Family History

Background/Objectives: A family history of Parkinson's disease (PD) is an important risk factor for developing PD. Because only a few studies have investigated the clinical characteristics of PD patients based on family history, this study compared the clinical characteristics of PD patients with and without a family history of PD. Methods: The study involved 356 patients with de novo PD. The data on the patients' PD family histories were obtained from the patients and their caregivers. Motor and non-motor PD symptoms were assessed using the appropriate scales. Results: Out of the 356 PD patients, 26 (7.3%) had a family history of PD. Compared with patients without a family history of PD, those with a family history of PD tended to be younger at diagnosis (67.9 years vs. 62.2 years, respectively; p = 0.009) and exhibited significantly more severe rigidity (p = 0.036). Motor subtype was not different between the PD patients with and without a family history. PD patients with a family history experienced significantly fewer falls/cardiovascular symptoms within the Non-Motor Symptoms Scale domains (p = 0.001) compared to their counterparts, although this was not statistically significant upon adjusting for age (p = 0.119). Conclusions: In de novo PD patients, having a family history of PD is associated with a younger age at diagnosis and more severe rigidity.

Analysis of mortality in Parkinson disease in China: Exploration of recent and future trends

Objectives

Parkinson disease (PD) is the third leading cause of mortality among middle-aged and older individuals in China. This study aimed to explore the trends and distribution features of PD mortality in China from 2013 to 2021 and make predictions for the next few decades.

Methods

Relevant data were obtained from the Chinese Center for Disease Control and Prevention Disease Surveillance Point system. The joinpoint regression model was used to evaluate trends. The R software was used to predict future trends.

Results

Age-standardized mortality rate (ASMR) of PD increased from 0.59 per 100,000 individuals to 1.22 per 100,000 individuals from 2013 to 2021, with an average annual percent change (AAPC) of 9.50 (95% CI: 8.24-10.78). The all-age ASMR of PD were higher in male individuals than in female individuals, and ASMR increased with age. The number of deaths and ASMR increased gradually from west to east and from rural to urban areas. Furthermore, ASMR is expected to increase to 2.66 per 100,000 individuals by 2040.

Conclusions

The heightened focus on the ASMR of PD among male individuals, urban areas, eastern China, and individuals aged ≥85 years has become a key determinant in further decreasing mortality, thereby exhibiting novel challenges to effective strategies for disease prevention and control.

A comprehensive examination of the evidence for whole of diet patterns in Parkinson's disease: a scoping review

Both motor and non-motor symptoms of Parkinson's disease (PD), a progressive neurological condition, have broad-ranging impacts on nutritional intake and dietary behaviour. Historically studies focused on individual dietary components, but evidence demonstrating ameliorative outcomes with whole-of-diet patterns such as Mediterranean and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) is emerging. These diets provide plenty of antioxidant rich fruits, vegetables, nuts, wholegrains and healthy fats. Paradoxically, the ketogenic diet, high fat and very low carbohydrate, is also proving to be beneficial. Within the PD community, it is well advertised that nutritional intake is associated with disease progression and symptom severity but understandably, the messaging is inconsistent. With projected prevalence estimated to rise to 1.6 million by 2037, more data regarding the impact of whole-of-diet patterns is needed to develop diet-behaviour change programmes and provide clear advice for PD management. Objectives and Methods: Objectives of this scoping review of both peer-reviewed academic and grey literatures are to determine the current evidence-based consensus for best dietary practice in PD and to ascertain whether the grey literature aligns. Results and Discussion: The consensus from the academic literature was that a MeDi/MIND whole of diet pattern (fresh fruit, vegetables, wholegrains, omega-3 fish and olive oil) is the best practice for improving PD outcomes. Support for the KD is emerging, but further research is needed to determine long-term effects. Encouragingly, the grey literature mostly aligned but nutrition advice was rarely forefront. The importance of nutrition needs greater emphasis in the grey literature, with positive messaging on dietary approaches for management of day-to-day symptoms.

[A portrait of a doctor with Parkinson's disease]

In a number of causes of Parkinson's disease (PD), occupation is periodically mentioned as a possible risk factor. However, a look at the complex impact of external factors on people of certain professions and the expansion of the area of risk factors in a rapidly changing world leads to the emergence of new studies. There is an assumption that the risk of developing PD is increased in doctors due to long-term exposure to stress. The presented case series describes the clinical features of 7 female doctors with PD. Of the 278 patients with PD referred for rehabilitation since 2016, 7 (2.5%) people were doctors by profession, all women, with stage II-III according to the Hoehn and Yahr scale, average age 65.28±7.94 years, and all referrals were registered during 2022-2023, which accounted for 10% of patients during this time. All patients were assessed for their medical history, clinical features of the underlying disease, comorbidity, MoCA scale, and self-reported physical activity. At the time of examination, the patients worked as primary care physicians or stopped working shortly before the examination due to the underlying disease. The patients' experience of PD was 4.0±2.0 years. The patients complained of unilateral tremor and uni- or bilateral gait disturbance, one patient had freezing. Additionally, the patients were bothered by comorbidities: deforming osteoarthrosis, obesity, arterial hypertension. Cognitive deficit was determined in 5 cases. The patients had reduced muscle strength, had no sports history and did not perform the minimum amount of physical activity recommended for maintaining health. These patients additionally had synergy of the underlying disease with degenerative processes of other body systems and lack of physical activity, which is a preventive factor in the development of PD and comorbid pathology.

The burden of Parkinson's disease in the Middle East and North Africa region, 1990-2019: results from the global burden of disease study 2019

BACKGROUND

Parkinson's disease (PD) remains a common disabling progressive neurodegenerative disorder. We aimed to report the prevalence, death and disability-adjusted life-years (DALYs) attributable to PD in the Middle East and North Africa (MENA) region and its 21 countries by age, sex and socio-demographic index (SDI), between 1990 and 2019.

METHODS

Publicly available data on the burden of PD in the MENA countries were retrieved from the Global Burden of Disease (GBD) 2019 project. The results are presented with age-standardised numbers and rates per 100,000 population, along with their corresponding 95% uncertainty intervals (UIs).

RESULTS

In 2019, PD had an age-standardised point prevalence of 82.6 per 100,000 population in MENA and an age-standardised death rate of 5.3, which have increased from 1990 to 2019 by 15.4% and 2.3%, respectively. In 2019, the age-standardised DALY rate of PD was 84.4, which was 0.9% higher than in 1990. The highest and lowest age-standardised DALY rates of PD in 2019 were found in Qatar and Kuwait, respectively. Also in 2019, the highest number of prevalent cases and number of DALYs were found in the 75-79 age group for both sexes. In 2019, females in MENA had an overall higher DALY rate. Furthermore, from 1990 to 2019 the burden of PD generally decreased with increasing socio-economic development, up to an SDI of around 0.4, and then increased with higher levels of SDI.

CONCLUSION

An upward trend was observed in the point prevalence of PD over the last three decades. This highlights the need to allocate more resources for research. Furthermore, properly equipped healthcare services are needed for the increasing number of patients with PD.

Alcohol and Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

A substantial body of research has examined the relationship between alcohol consumption and risk of Parkinson's disease (PD).

OBJECTIVE

To provide an updated systematic review and meta-analysis of observational studies examining the relationship between alcohol consumption and risk of PD.

METHODS

Eligible studies comparing PD risk in ever vs. never alcohol drinkers were sourced from six databases. Outcomes were pooled using standard meta-analysis techniques. Separate female and male estimates were generated from studies reporting sex-specific data. Additionally, cohort studies stratifying participants by quantity of alcohol intake were integrated in a dose-response analysis.

RESULTS

52 studies were included, totaling 63,707 PD patients and 9,817,924 controls. Our meta-analysis supported a statistically significant overrepresentation of never drinkers among PD subjects; odds ratio (OR) for ever drinking alcohol 0.84 (95% confidence interval (CI) 0.76 - 0.92). A subgroup analysis revealed similar effect estimates in females and males. A further synthesis of seven cohort studies suggested a negative, dose-dependent association between alcohol and risk of PD.

CONCLUSION

In the absence of a known neuroprotective pathway, there may be reason to doubt a true biological effect. The role of survivor bias, selection and recall bias, misclassification, and residual confounding requires consideration. Alternatively, observations might be attributable to reverse causation if those predestined for PD alter their alcohol habits during the preclinical phase. Major limitations of our study include high between-study heterogeneity (I2 = 93.2%) and lack of adjustment for key confounders, namely smoking status.

Effect of modifiable risk factors in Parkinson's disease: A case-control study looking at common dietary factors, toxicants, and anti-inflammatory medications

OBJECTIVE

To investigate how common modifiable exposures, including dietary factors, select toxicants, and anti-inflammatory medications, may affect Parkinson's disease.

METHODS

Using surveys, a case-control study was conducted at a medical center, comparing Parkinson's disease patients (N  =  149) and healthy controls (N  =  105). Subjects reported exposure to red meats, vegetables, alcohol, tobacco, anti-inflammatory medications, and pesticides. The relationship between exposures and Parkinson's disease diagnosis was analyzed by logistic regression to generate odds ratio and 95% confidence interval.

RESULTS

Consuming red meat "sometimes" or "always" was positively associated with Parkinson's disease as compared to eating red meats "rarely" or "never"; (odds ratio  =   2.15, 95% confidence interval   =   1.06, 4.39; p  =  0.03) and (odds ratio   =   4.47, 95% confidence interval   =   1.67, 11.94; p  =  0.003), respectively. Exposure to pesticides showed a positive association with Parkinson's disease (odds ratio  =   2.84, 95% confidence interval   =   1.34, 6.00; p  =  0.007). "Always" use of aspirin was inversely associated with Parkinson's disease (odds ratio  =   0.32, 95% confidence interval   =   0.14, 0.70; p  =  0.004). "Ever" having used anti-histamines was inversely associated with Parkinson's disease (odds ratio  =   0.37, 95% confidence interval  =  0.17, 0.81; p  =  0.01).

DISCUSSION

Our study suggests that there are modifiable external factors that are associated with Parkinson's disease. The present study can thus assist clinicians, policy makers, and people living with Parkinson's disease in improving the experience and management of Parkinson's disease.

The Role of Diet and Dietary Patterns in Parkinson's Disease

Parkinson's Disease (PD) is a neurodegenerative disorder associated with diminished nutrition status and decreased quality of life. While the prevalence of PD is expected to increase, no preventative or curative therapy for PD exists at this time. Although nutrition and diet represent modifiable risk factors for reducing chronic disease risk, research on the impact of single nutrients on PD has yielded mixed results. As a result, this single-nutrient approach may be the driving force behind the inconsistency, and a holistic dietary approach may overcome this inconsistency by accounting for the interactions between nutrients. The following review aims to examine the impact of a generally healthy dietary pattern, the protein-restricted diet (PRD), the ketogenic diet (KD), the Mediterranean diet (MD), and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet on PD risk, progression, and severity. While most of the included studies support the role of diet and dietary patterns in reducing the risk of PD or alleviating PD severity, the inconsistent results and need for further evidence necessitate more research being conducted before making dietary recommendations. Research on the potential beneficial effects of dietary patterns on PD should also investigate potential risks.

Relationships of Nutritional Factors and Agrochemical Exposure with Parkinson's Disease in the Province of Brescia, Italy

Environmental exposures to agrochemicals and nutritional factors may be associated with Parkinson's Disease (PD). None of the studies to date has examined the combined effects of diet and agricultural chemical exposure together. To address these research gaps, we aimed to assess the association of nutritional factors and agrochemical exposure with the risk of PD. A hospital-based case-control study was conducted. Multivariable logistic regressions were used to estimate the association of nutritional and agrochemical exposures with PD, adjusting for gender, age, socio-economic status, head injury, family history, smoking, metals exposure, and α-synuclein gene polymorphism. Weighted Quantile Sum (WQS) regression was applied to examine the effect of dietary components as a mixture. We recruited 347 cases and 389 controls. Parent history of PD (OR = 4.15, 95%CI: 2.10, 8.20), metals exposure (OR = 2.50, 95%CI: 1.61-3.89), SNCA rs356219 polymorphism (OR = 1.39, 95%CI: 1.04-1.87 for TC vs. TT; OR = 2.17, 95%CI: 1.43-3.28 for CC vs. TT), agrochemical exposures (OR = 2.11, 95%CI: 1.41-3.16), and being born in the Brescia province (OR = 1.83, 95%CI: 1.17-2.90) were significantly associated with PD. Conversely, fish intake and coffee consumption had a protective effect. The study confirmed the role of environmental exposures in the genesis of PD. Fish intake and coffee consumption are protective factors even when agricultural chemical exposures exist. Genetic factors and metals exposure were confirmed as risk factors for PD.

Global Trends in the Incidence, Prevalence, and Years Lived With Disability of Parkinson's Disease in 204 Countries/Territories From 1990 to 2019

Background: Parkinson's disease (PD) is an increasing challenge to public health. Tracking the temporal trends of PD burden would inform health strategies.

Methods: Data of PD burden was obtained from the Global Burden of Disease 2019. Trends in the incidence, prevalence, and years lived with disability (YLDs) of PD were estimated using the annual percentage change (EAPC) and age-standardized rate (ASR) from 1990 to 2019. The EAPCs were calculated with ASR through a linear regression model.

Results: The overall ASR of the incidence, prevalence, and YLDs of PD increased from 1990 to 2019, and their EAPCs were 0.61 (95% confidence interval [CI]: 0.58–0.65), 0.52 (95% CI: 0.43–0.61), and 0.53 (95% CI: 0.44–0.62). The largest number of PD patients was seen in the groups aged more than 65 years, and the percentage rapidly increased in the population aged more than 80 years. Upward trends in the ASR of PD were observed in most settings over the past 30 years. Incident trends of ASR increased pronouncedly in the United States of America and Norway, in which the respective EAPCs were 2.87 (95% CI: 2.35–3.38) and 2.14 (95% CI: 2.00–2.29). Additionally, the largest increasing trends for prevalence and YLDs were seen in Norway, with the respective EAPCs of 2.63 (95% CI: 2.43–2.83) and 2.61 (95% CI: 2.41–2.80). However, decreasing trends in PD appeared in about 30 countries, particularly Italy and the Republic of Moldova.

Conclusions: Increasing trends in the burden of PD were observed globally, and in most regions and countries from 1990 to 2019. Our findings suggested that the control and management of PD should be strengthened, especially when considering the aging tendency of the population.