Changes in Body Composition Before and After Parkinson's Disease Diagnosis

Association of Body Mass Index and Parkinson Disease: A Bidirectional Mendelian Randomization Study

BACKGROUND AND OBJECTIVES

The role of body mass index (BMI) in Parkinson disease (PD) is unclear. Based on the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in PD (Courage-PD) consortium, we used 2-sample Mendelian randomization (MR) to replicate a previously reported inverse association of genetically predicted BMI with PD and investigated whether findings were robust in analyses addressing the potential for survival and incidence-prevalence biases. We also examined whether the BMI-PD relation is bidirectional by performing a reverse MR.

METHODS

We used summary statistics from a genome-wide association study (GWAS) to extract the association of 501 single-nucleotide polymorphisms (SNPs) with BMI and from the Courage-PD and international Parkinson Disease Genomics Consortium (iPDGC) to estimate their association with PD. Analyses are based on participants of European ancestry. We used the inverse-weighted method to compute odds ratios (ORIVW per 4.8 kg/m2 [95% CI]) of PD and additional pleiotropy robust methods. We performed analyses stratified by age, disease duration, and sex. For reverse MR, we used SNPs associated with PD from 2 iPDGC GWAS to assess the effect of genetic liability toward PD on BMI.

RESULTS

Summary statistics for BMI are based on 806,834 participants (54% women). Summary statistics for PD are based on 8,919 (40% women) cases and 7,600 (55% women) controls from Courage-PD, and 19,438 (38% women) cases and 24,388 (51% women) controls from iPDGC. In Courage-PD, we found an inverse association between genetically predicted BMI and PD (ORIVW 0.82 [0.70-0.97], p = 0.012) without evidence for pleiotropy. This association tended to be stronger in younger participants (≤67 years, ORIVW 0.71 [0.55-0.92]) and cases with shorter disease duration (≤7 years, ORIVW 0.75 [0.62-0.91]). In pooled Courage-PD + iPDGC analyses, the association was stronger in women (ORIVW 0.85 [0.74-0.99], p = 0.032) than men (ORIVW 0.92 [0.80-1.04], p = 0.18), but the interaction was not statistically significant (p-interaction = 0.48). In reverse MR, there was evidence for pleiotropy, but pleiotropy robust methods showed a significant inverse association.

DISCUSSION

Using an independent data set (Courage-PD), we replicate an inverse association of genetically predicted BMI with PD, not explained by survival or incidence-prevalence biases. Moreover, reverse MR analyses support an inverse association between genetic liability toward PD and BMI, in favor of a bidirectional relation.

A systematic review of Behaviour Change Interventions to improve exercise self-efficacy and adherence in people with Parkinson's disease using the Theoretical Domains Framework

Physical activity and exercise can limit the development of sarcopenia in Parkinson's Disease. This review aims to evaluate the potential effects of behavioural change (BC) interventions on exercise self-efficacy and adherence in people with Parkinson's. We searched nine databases and included randomised and non-randomised studies reporting exercise self-efficacy, quality of life (QoL), physical function and/or exercise adherence. Two reviewers independently screened, data extracted, and assessed risk of bias and certainty of evidence. The interventions were mapped to the Theoretical Domains Framework. Eleven studies (n=901) were included. Four were randomised trials and risk of bias was mixed. Most interventions were multi-component, including education, behavioural techniques, and support groups. The most effective domains appear to be Behavioural regulation, Belief about Capabilities, Social influences, Reinforcement and Goals. Future research should examine multi-component BC interventions encompassing the five most effective TDF domains.

Parkinson's Disease: Cells Succumbing to Lifelong Dopamine-Related Oxidative Stress and Other Bioenergetic Challenges

The core pathological event in Parkinson's disease (PD) is the specific dying of dopamine (DA) neurons of the substantia nigra pars compacta (SNc). The reasons why SNc DA neurons are especially vulnerable and why idiopathic PD has only been found in humans are still puzzling. The two main underlying factors of SNc DA neuron vulnerability appear related to high DA production, namely (i) the toxic effects of cytoplasmic DA metabolism and (ii) continuous cytosolic Ca2+ oscillations in the absence of the Ca2+-buffer protein calbindin. Both factors cause oxidative stress by producing highly reactive quinones and increasing intra-mitochondrial Ca2+ concentrations, respectively. High DA expression in human SNc DA neuron cell bodies is suggested by the abundant presence of the DA-derived pigment neuromelanin, which is not found in such abundance in other species and has been associated with toxicity at higher levels. The oxidative stress created by their DA production system, despite the fact that the SN does not use unusually high amounts of energy, explains why SNc DA neurons are sensitive to various genetic and environmental factors that create mitochondrial damage and thereby promote PD. Aging increases multiple risk factors for PD, and, to a large extent, PD is accelerated aging. To prevent PD neurodegeneration, possible approaches that are discussed here are (1) reducing cytoplasmic DA accumulation, (2) blocking cytoplasmic Ca2+ oscillations, and (3) providing bioenergetic support.

Body Mass Index, Abdominal Adiposity, and Incidence of Parkinson Disease in French Women From the E3N Cohort Study

BACKGROUND AND OBJECTIVES

Previous studies on the relationship between body mass index (BMI) and Parkinson disease (PD) provided inconsistent results, likely due to reverse causation explained by weight loss during the prodromal phase. We examined the association of BMI and abdominal adiposity with PD incidence using lagged analyses to address the potential for reverse causation and compared BMI trajectories in patients before diagnosis and matched controls.

METHODS

We used data from the E3N cohort study of French women with a 29-year follow-up (1990-2018). BMI (kg/m²) was computed based on self-reported weight and height up to 11 times; up to 6 waist circumference (WC) and hip circumference measures were available. PD diagnoses were validated based on medical records and drug claim databases. Multivariable time-varying Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs according to BMI categories (underweight <18.5 kg/m²; normal = [18.5-25.0[ kg/m²; overweight = [25.0-30.0[ kg/m²; obese ≥30.0 kg/m²). Exposures were lagged by 5 years in main analyses; we used longer lags (10 and 20 years) in sensitivity analyses. We examined trajectories of BMI categories within a nested case-control study using multivariable generalized estimating equations multinomial logistic models.

RESULTS

Of 96,702 women (baseline age = 40-65 years), 1,164 developed PD. PD incidence was lower (HR = 0.76, 95% CI = 0.59-0.98, p = 0.032) among women with obesity compared with those with normal BMI. There was a similar association in analyses using longer lag times (20 years, 598 cases, HR = 0.52, 95% CI = 0.30-0.88, p = 0.016). A similar pattern was seen for WC and waist-height ratio but not waist-hip ratio. Trajectories of BMI categories (1,196 patients and 23,876 controls) showed that obesity was less frequent in patients with PD before diagnosis than in controls, with a statistically significant difference 29 years before. In addition, the frequency of obesity decreased 5-10 years before diagnosis in patients.

DISCUSSION

In this large cohort of women with a long follow-up, obesity was associated with a lower hazard of PD, even when measured 20 years before diagnosis, in agreement with Mendelian randomization studies. Our analyses underscore the importance of lagged analyses to account for reverse causation. These findings warrant further investigations to understand the mechanisms underlying this inverse association.

Association of Early Weight Change With Cognitive Decline in Patients With Parkinson Disease

BACKGROUND AND OBJECTIVE

To examine whether early weight change is associated with subsequent deterioration in cognitive function, including overall performance and specific domains, in Parkinson disease (PD).

METHODS

This observational study used data from the Parkinson Progression Markers Initiative cohort. The patients underwent annual nonmotor assessments covering neuropsychiatric, sleep-related, and autonomic symptoms for up to 8 years of follow-up. Cognitive function was measured using the Montreal Cognitive Assessment (MoCA) and detailed neuropsychological testing. Linear mixed-effects models were applied to investigate the association of early weight change with longitudinal evolution of cognitive and other nonmotor symptoms.

RESULTS

A total of 358 patients with early PD were classified into weight loss (decrease of >3% body weight during the first year; n = 98), weight maintenance (within ±3%; n = 201), and weight gain (increase of >3%; n = 59) groups. The weight loss group showed a significantly faster decline in MoCA scores than the weight maintenance group (β = -0.19, 95% CI -0.28 to -0.10). With respect to specific cognitive domains, the weight loss group showed a steeper decline in sematic fluency test scores (β = -0.37, 95% CI -0.66 to -0.08) and MoCA phonemic fluency scores (β = -0.18, 95% CI -0.31 to -0.05) and, to a lesser extent, Letter-Number Sequencing scores (β = -0.07, 95% CI -0.14 to 0.01) compared with the weight maintenance group. Conversely, the weight gain group showed a slower decline in the Symbol Digit Modalities Test scores (β = 0.34, 95% CI 0.05 to 0.63), although no association was found with longitudinal changes in MoCA scores. We did not find any significant effects of weight change on the progression of other nonmotor symptoms.

DISCUSSION

Early weight loss was associated with a faster progression of decline in global cognitive function and executive function in patients with PD, whereas early weight gain was associated with a slower progression of decline in processing speed and attention. The impact of early weight change on nonmotor symptoms seemed to be specific to cognition.

Prevalence of sarcopenia in Parkinson's disease: A systematic review and meta-analysis

We meta-analysed the sarcopenia prevalence among patients with Parkinson´s disease (PD) in comparison to a control group and tested the effects of age, sex, sarcopenia assessments, and PD progression in the sarcopenia prevalence. The literature search was performed using five databases in March 2022. The prevalence of sarcopenia in patients with PD was 3 times higher than in the control group (OR 3.98). Subgroup analyses showed that among individuals aged ≥ 70 years the higher prevalence of sarcopenia in PD compared to controls (OR 5.32, P=0.08) tended to be higher (P=0.08) than the group < 70 years. Regarding PD progression, the prevalence of sarcopenia was not different between individuals scoring < 2.5 and ≥ 2.5 in the Hoehn and Yahr scale. Patients with PD have a higher probability of developing sarcopenia when compared with the control group and older PD patients trended to have even higher chance of sarcopenia than their older controls.

Parkinson's Disease Case Ascertainment in the Sister Study: A Cohort for Environmental Health Research

BACKGROUND

Large prospective studies are essential for investigating the environmental causes of Parkinson's disease (PD), but PD diagnosis via clinical exams is often infeasible in such studies.

OBJECTIVE

To present case ascertainment strategy and data collection in a US cohort of women.

METHODS

In the Sister Study (n = 50,884, baseline ages 55.6±9.0), physician-made PD diagnoses were first reported by participants or their proxies. Cohort-wide follow-up surveys collected data on subsequent diagnoses, medication usage and PD-relevant motor and nonmotor symptoms. We contacted self-reported PD cases and their treating physicians to obtain relevant diagnostic and treatment history. Diagnostic adjudication was made via expert review of all available data, except nonmotor symptoms. We examined associations of nonmotor symptoms with incident PD, using multivariable logistic regression models and reported odds ratio (OR) and 95% confidence intervals (CI).

RESULTS

Of the 371 potential PD cases identified, 242 diagnoses were confirmed. Compared with unconfirmed cases, confirmed cases were more likely to report PD diagnosis from multiple sources, medication usage, and motor and nonmotor features consistently during the follow-up. PD polygenic risk score was associated with confirmed PD (ORinter-quartile range = 1.74, 95% CI: 1.45-2.10), but not with unconfirmed cases (corresponding OR = 1.05). Hyposmia, dream-enacting behaviors, constipation, depression, unexplained weight loss, dry eyes, dry mouth, and fatigue were significantly related to PD risk, with ORs from 1.71 to 4.88. Only one of the eight negative control symptoms was associated with incident PD.

CONCLUSION

Findings support our PD case ascertainment approach in this large cohort of women. PD prodromal presentation is likely beyond its well-documented profile.

Effects of a Resistance Training Protocol on Physical Performance, Body Composition, Bone Metabolism, and Systemic Homeostasis in Patients Diagnosed with Parkinson's Disease: A Pilot Study

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor impairments and it is correlated with loss of bone mineral density. This study aimed to analyze the effects of resistance training on bone metabolism, systemic homeostasis, body composition, and physical performance in people with PD. Thirteen subjects (age 64.83 ± 5.70) with PD diagnosis were recruited. Participants performed neuromuscular tests, body composition assessment, and blood sample analysis at baseline, and after an 11 weeks-training period. Each training session lasted 90 min, three times a week. The participants had significant improvements in the timed up and go (p < 0.01), sit to stand (p < 0.01), dominant peg-board (p < 0.05), dominant foot-reaction time (p < 0.01), and functional reach tests (p < 0.05). They showed better pressure foot distributions in the left forefoot (p < 0.05) and hindfoot (p < 0.05) and increased cervical right lateral bending angle (p < 0.05). The protocol affects bone metabolism markers osteocalcin (p < 0.05), calcium (p < 0.01), PTH (p < 0.01), the C-terminal telopeptide (CTX) (p < 0.01), and vitamin D (p < 0.05). Eleven weeks of resistance training improved manual dexterity, static and dynamic balance, reaction time, cervical ROM, and reduced bone loss in people with PD.

Initial BMI and Weight Loss Over Time Predict Mortality in Parkinson Disease

OBJECTIVES

Although weight loss is a frequent symptom in Parkinson disease (PD), there have been few studies on the association between body mass index (BMI) and mortality. The objective of this study was to investigate the association between BMI and change in BMI at diagnosis in patients with PD and all-cause mortality.

DESIGN

Cohort study using Korean National Health Insurance Service-Elderly Cohort data.

SETTING AND PARTICIPANTS

Patients with new-onset PD were selected using the International Classification of Diseases 10th edition code (G20). Then, patients who were diagnosed more than 3 times with PD and had been prescribed anti-parkinsonian medication for ≥30 days were included. Those with a combined diagnosis of atypical parkinsonism and secondary parkinsonism were excluded.

METHODS

The primary outcome was all-cause mortality. Anthropometric data, including height and weight, were obtained from the health screening data to calculate BMI. The Cox proportional hazards model was used to assess mortality risk by BMI.

RESULTS

Among the 2703 patients with PD, 492 (18.20%) died during the 11-year follow-up period. There was a significant inverse dose-response relationship between baseline BMI and mortality (<18.5 kg/m²: hazard ratio [HR], 1.872, 95% CI, 1.338-2.494; 23-25 kg/m²: HR, 0.695, 95% CI, 0.546-0.886; 25-30 kg/m²: HR, 0.644, 95% CI, 0.476-0.869; ≥30 kg/m²: HR, 0.396, 95% CI, 0.165-0.950). Change in BMI of 10% revealed a significant association with mortality. Subgroup analyses by sex showed a significant inverse dose-response relationship between BMI and all-cause mortality only in women.

CONCLUSIONS AND IMPLICATIONS

We demonstrated an inverse dose-response association between BMI at diagnosis and mortality in patients with PD, especially in women. Early detection of PD before weight loss progression and proper management might improve mortality. The small number of obese PD participants in our study should be considered when interpreting and generalizing results.

Low-Density Lipoprotein Cholesterol and the Risk of Rheumatoid Arthritis: A Prospective Study in a Chinese Cohort

Objective: This study aimed to investigate whether low-density lipoprotein cholesterol (LDL-C) concentration was associated with the risk of rheumatoid arthritis (RA) in Chinese adults. Methods: The study included the 97,411 participants in the Kailuan Study without RA, with complete baseline LDL-C data, and who did not use lipid-lowering medications at baseline or during follow-up. We used Cox proportional hazards modeling to calculate the hazard ratio (HR) and 95% confidence interval (95% CI) of RA according to baseline LDL-C tertiles, adjusting for age, sex, body mass index, HDL-C, triglycerides, diabetes, hypertension, alcohol consumption, and smoking. We also calculated the HR and 95% CI of RA using updated LDL-C measurements prior to the end of follow-up, adjusting for covariates. Results: We identified 97 incident RA cases between 2006 and 2018. After adjusting for potential confounders, updated LDL-C concentration—rather than baseline LDL-C—was inversely associated with RA risk. The adjusted HR of RA was 0.64 (95% CI: 0.38, 1.09; p-trend = 0.10) comparing the two extreme baseline LDL-C tertiles, and 0.38 (95% CI: 0.22, 0.64; p-trend < 0.01) comparing the two extreme tertiles of the updated LDL-C concentrations. Conclusions: In this prospective study, high LDL-C concentrations, when measured closest to RA diagnosis or the end of follow-up, were associated with a low risk of RA. These findings highlight the changes in LDL-C prior to RA diagnosis, and the importance of including lipid analyses into studies of the pathogenesis of RA.