Synergy of pandemics-social isolation is associated with worsened Parkinson severity and quality of life

The study investigates whether social isolation and loneliness are associated with worsened Parkinson’s disease (PD) symptom severity and lower quality of life (QoL). Social isolation is defined as objective lack of social contact and networks, while loneliness is a subjective perception of social isolation. Prior work shows loneliness affects stress responses, immune function, sleep, cognition, and is linked to increased morbidity and mortality in aging. With PD prevalence rapidly increasing globally and multiple disease-related and social factors (e.g., stigma, communication difficulties) predisposing people with PD (PWP) to isolation, the authors set out to evaluate the relationship between social health (loneliness, friendships, relationship status, social performance/satisfaction) and PD severity/QoL, especially relevant during COVID-19-related social distancing.

The paper summarizes evidence that social support buffers stress; lack of support and loneliness worsen stress susceptibility. Loneliness and smaller social networks independently predict poorer immune responses (e.g., to vaccination), and loneliness is associated with stress-related inflammatory and neuroendocrine responses in both older and middle-aged adults. Loneliness influences attention to threat, circadian rhythms, and sleep quality, potentially increasing anxiety, fatigue, and irritability. In older adults, social isolation and loneliness are linked to higher mortality risk and adverse outcomes (e.g., depression, cardiovascular risk, reduced well-being). In PD specifically, social roles, stigma, and disease burden may exacerbate isolation. Despite extensive general literature, there is limited PD-specific research on social isolation/loneliness, highlighting the need to examine their associations with PD severity and QoL.

Design: Prospective, observational, internet-based cohort (CAM Care PD) initiated in 2013, with this report presenting a cross-sectional analysis of baseline data. IRB-approved (IRB #1433-132), registered at ClinicalTrials.gov (NCT01214191). Informed consent obtained online; data managed in REDCap. Participants: Adults with self-reported idiopathic PD. Of 2,138 respondents reporting a diagnosis of Parkinson’s, 1,795 indicated they were aware of a PD diagnosis; a subset with idiopathic PD (n ≈ 1,527 per Table 1) was analyzed. Loneliness prevalence was 17% (261/1,527). Measures: Primary PD severity outcome was the cumulative PRO-PD score, a patient-reported instrument assessing severity of 33 motor and non-motor PD symptoms using sliders (0–100 per item) averaged over the prior week. PRO-PD has shown correlations with years since diagnosis, Hoehn & Yahr stage, UPDRS, PDQ-39, and PROMIS Global. QoL was assessed with PROMIS Global (chosen by NIH guidance for broad applicability). Social health was assessed via PROMIS Global social performance and satisfaction items and targeted statements (e.g., “I am lonely,” “I have lots of friends”), as well as relationship status. Additional variables included perceived stress (“I have a lot of stress”), stress management, and exercise frequency. Analysis: Associations between PRO-PD and social health measures were evaluated using regression models. Adjusted analyses controlled for age, gender, income, and years since diagnosis. Trends in PRO-PD over time and relationships between social performance/satisfaction and PRO-PD were examined. Descriptive statistics summarized demographics, Hoehn & Yahr stage, PRO-PD, PROMIS Global, and self-reported 6-month progression categories (improved/stable/worsened).

- PRO-PD increased over time in the PD cohort (R² = 0.11; P < 0.01). - Worse social health correlated with greater PD severity: PRO-PD scores increased as PROMIS social performance and social satisfaction decreased. - Loneliness magnitude: Individuals endorsing “I am lonely” had 55% greater symptom severity than those not lonely (p < 0.01). - Friendships: Individuals reporting “I have a lot of friends” had 21% fewer symptoms than those with few/no friends (p < 0.01). - Adjusted effects: After controlling for age, gender, income, and years since diagnosis, agreeing with “I am lonely” was associated with a 327-point higher PRO-PD score; agreeing with “I have lots of friends” was associated with a 19-point lower PRO-PD score (both P < 0.01). - Symptom-level differences: Lonely individuals rated all 33 PRO-PD symptoms more severe than non-lonely peers. Largest differences (points out of 100): withdrawal/loss of interest (+23), motivation/initiative (+23), depression (+22), anxiety (+20). - Quality of life: Loneliness and friendships predicted QoL more strongly than tremor severity (per figures). PROMIS Global mean: total 36.6 (6.7); lonely 30.1 (6.2) vs not lonely 38.3 (6.0). Relationship status tracked with QoL; only 9% of those with “Excellent” QoL were single. - Demographics/staging (Idiopathic PD n=1,527): Mean age 62.9 years; years since diagnosis 4.8. Hoehn & Yahr distribution included 53.6% stage 1, 16.4% stage 2, 24.1% stage 3, 2.6% stage 4, 0.3% stage 5. - Perceived progression (6 months): improved 9.6%, stable 52.5%, worsened 37.3%; loneliness was more prevalent among those reporting worsening. - Other modifiable factors: Endorsing “I have a lot of stress” associated with faster progression (P < 0.01). Practicing stress management and frequent exercise associated with slower progression. The negative impact of loneliness on PRO-PD (t = 327; P < 0.01) was of similar magnitude but opposite direction to the beneficial effect of daily exercise (−299; P < 0.01).

The study demonstrates a strong association between social isolation/loneliness and worse patient-reported PD severity and QoL. These findings support the hypothesis that social health is an important, modifiable determinant in PD. While causality cannot be established from cross-sectional data, the consistent associations across global QoL, social functioning/satisfaction, and symptom-level severity suggest social health plays a meaningful role in the PD symptom experience and perceived progression. The results are especially relevant in the context of COVID-19, where social distancing may exacerbate isolation, potentially worsening PD outcomes. Clinically, routine screening for loneliness and social connectedness, as well as proactive interventions (e.g., social prescribing, virtual support and exercise groups), could mitigate adverse impacts. For research, incorporating social health measures into PD study designs and analytical models (e.g., adjusting for loneliness) may reduce confounding and clarify influences on progression and QoL.

Social isolation and loneliness are associated with greater PD symptom severity and lower quality of life in people with Parkinson’s disease. The study highlights social health as a potentially modifiable factor that warrants clinical attention and policy consideration, particularly during pandemic-related social distancing. The authors advocate keeping PWP socially connected using virtual modalities and social prescribing. Future research should test causal pathways and determine whether improving social health can slow PD progression and improve QoL, while incorporating loneliness as a covariate in PD studies.

- Cross-sectional analysis limits causal inference; directionality between loneliness and symptom severity/QoL cannot be determined. - Sample may not represent the broader PD population (predominantly Caucasian, younger, and female), limiting generalizability. - Reliance on self-reported, subjective measures (e.g., loneliness, symptoms) may be confounded by depression, anxiety, apathy, fatigue, pain, or denial; social isolation inferred from multiple questions rather than a single validated isolation index. - Quality and depth of relationships were not assessed; marital/partnership status may not reflect relational quality. - PRO-PD, while previously validated and correlated with established scales, is a relatively novel instrument without long historical use; lack of objective clinical exams due to online design. - Potential measurement and interpretation variability for concepts like loneliness and social isolation across individuals.