Mindfulness for Lonely Older Adults With Emigrant Children

The feasibility of the MBI will be evaluated using the following criteria: recruitment and retention rates. The recruitment rate is ≥80% of subject recruitment of the study, time required to recruit to target sample size (≤4 months for recruiting 45 subjects; ≤9 months for recruiting 90 subjects), Adverse Effects reported by the subjects is ≤5% for the whole study, attendance rate is ≥75% of subjects attend each session of health education, reasons for drop out or withdrawal from the study record in number and percentage, program completion rate of the subject ≥70%.

Acceptability will be assessed via a self-developed evaluation form completed after the 12-week MBI training.

The form has three-part: Part 1 includes 4 questions on perceived benefits of MBI; Part 2 includes 8 questions on satisfaction with MBI class arrangement; Part 3 includes 3 questions for suggestions and feedbacks. Questions 1 to 12 (part 1 and 2) use a five-point Likert Scale (5 = "Strongly agree", 1 = "strongly not agree"). Question 10 assesses subjects' willingness to continue MBI practice. Questions 13 and 15 (part 3) are open-ended, collecting "other comments" and suggestions for improving the MBI class, respectively.

The Chinese version of the Revised University of California Los Angeles (R-UCLA) 3-item Loneliness Short Scale used to measure subjective feelings of loneliness. This 3-item, 4-point Likert scale (0 = "never", 3 = "always") yields scores from 0 to 9, with higher scores indicating greater perceived loneliness. Cronbach's for the Chinese R-UCLA is 0.87.

The Chinese Pittsburgh Sleep Quality Index (PSQI) assesses sleep quality over past month across seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, sleep medication, and daytime dysfunctions. This 19-item, 4-point Likert scale (0 = "no difficulty, 3 = "severe difficulty") generates scores from 0 to 21, with ≥8 indicates sleep disturbance. Cronbach's α for the Chinese PSQI is 0.79.

The Chinese 10-item Perceived Stress Scale (PSS-10) measures stress using a 5-point Likert scale (0 = "never", 4 = "very often") generate score from 0 to 40. It includes four positive items assessing stress adaptation and six negative items evaluating negative affective reactions and lack of control. Higher scores indicate greater stress. Cronbach's α for PSS-10 is 0.83.

The EuroQol 5-Dimension 5-Level (EQ-5D-5L) HK evaluates QoL across five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has five levels (no problem to extreme problems). A utility score (-1 to 1; <1 = "worse than death", 0 = "death", 1 = "full health") is derived for clinical and economic appraisal.

Chinese Five Facet Mindfulness Questionnaire (FFMQ-15) measures five mindfulness facets: Observe (Items 5, 8, 10, 12), Describing (Items 6, 13, 15), Act with awareness (Items 1, 2, 4, 7), Nonjudging (Items 9, 11, 14), and Nonreactive (Item 3). Each item is scored on a 5-point Likert scale (1 = "never or very rarely true", 5 = "very often or always true" for Observing, Describing, Nonreactivity; reversed for Acting with Awareness, Nonjudging). Higher summed scores indicate greater mindfulness. Cronbach's α for FFMQ-15 is 0.82 .

• Blood pressure (BP) is measured using a validated upper-arm automated system after a 10-minute rest; averaging two readings taken 1-minute apart.
• Anthropometric measures include waist circumference (nearest 0.1 cm), height (nearest 0.5cm no shoes), and body weight (nearest 0.1kg, light clothing, no shoes/socks, emptying bladder).
• Body mass index is calculated as weight (kg) divided by height (m2).

Behavioural outcomes, including change in dietary pattern, change in smoking and drinking habits including the type and amount, will be collected via a self-designed data sheet at each follow-up visit.