2.3. Data Collection

Data collection was conducted via the free annual health assessment program for the elderly aged 65 years and over, funded by the Chinese Government. Physicians working in village clinics helped invite eligible residents based on the census register. After their annual health assessment, residents were invited to participate in the study and informed consent was obtained directly from each participant or a family caregiver. Face-to-face individual interviews lasting about 30 min were conducted to collect data in local village clinics by the investigators, who were researchers and health professionals with at least ten years of experience working in public health recruited from the local township hospitals.

A standardized two-day training program about data collection procedures was provided to all investigators, and a pilot survey with 50 rural elders was carried out to guarantee the measurements. A retraining course lasting around two hours was conducted after the pilot survey, and refresher training was provided as needed during the investigation process. Modifications were made to the measurements, especially the demographic information sheet, according to findings from the pilot survey. The researchers checked data before the end of each survey day, and logical errors or missing information were handled the following day by contacting the village doctor or the participant directly. Data collection included demographic information, cognitive function, lifestyle, psychosocial factors, and health-related factors. Measurements are described below.

Participants’ demographic information was collected through a demographic information sheet, including age, gender, marital status, education, family income, and living situation.

The Chinese version of the Mini-Mental Status Examination (MMSE) was applied to assess participants’ cognitive function, including orientation to time and place, registration, attention and calculation, recall, language, and visual construction [18]. The MMSE is widely used globally for cognitive impairment assessment, with excellent sensitivity and specificity. The MMSE consists of 30 items, with each item rated as 0 or 1 according to the interviewee’s response, yielding a total maximum score of 30. Participants with higher scores indicate a better cognitive function. Cut-off points, based on the education background of the interviewee, were ≤17 for illiteracy, 20 for primary school, and 24 for secondary school [19]. The Chinese MMSE showed a Cronbach’s alpha coefficient of 0.722 in this study.

Lifestyle factors were investigated via a self-report approach. A lifestyle information sheet was developed based on a literature review and expert panel review. Revisions to the information sheet were made according to expert feedback and findings from the pilot study. Information collected included regular house/farm work, smoking, alcohol consumption, and habitual tea consumption.

A self-reporting approach was used to collect information about sleep quality, memory complaints, and social interactions with others in the neighborhood. Through self-reporting, participants rated their social interactions as poor, satisfactory or good.

Coping style was assessed using the 20-item Simplified Coping Style Questionnaire (SCSQ) [20]. The SCSQ includes two dimensions of coping style, positive coping with 12 items and negative coping with 8 items. Each item was rated on a 4-point Likert scale, ranging from 0 (never use) to 3 (often use). The total score was the mean difference of positive coping score and negative coping score, with a positive number indicating a positive coping style, while a negative number indicates a negative coping style.

The health-related factors investigated included cardiovascular risk factors and other chronic conditions. Four approaches, including health records, self-reports, physical examinations, and assessment scale, were employed to collect data about health-related risk factors. Health records were reviewed to collect comprehensive information about health-related factors, including hypertension, type 2 diabetes, cerebrovascular disease, heart disease, hyperlipidemia, and renal disease. Supplementary information not included in electronic health records, such as hearing impairment, and traumatic brain injuries, was sought through self-report questions. Height, weight, waistline, and vision were measured by trained health professionals using the same instrument. Body mass index (BMI) was then calculated and categorized into one of three groups: underweight, normal weight and overweight.

The Activities of Daily Living Scale (ADLS) was applied to assess both physical activities of daily living (ADL) and instrumental ADL [21]. The ADLS is a 14-item scale, with each item rated on a 4-point Likert scale, ranging from 1 (totally independent) to 4 (totally dependent), yielding a maximum total score of 56. Higher scores indicate higher dependence. A total score of 22 points or above, or more than one item rated as 3 points or more, was identified as ADL dependence. The physical ADL subscale includes 6 items with a total score of 6 points, indicating dependence in physical ADL. The IADL subscale consists of 8 items with a total score of 8 points, indicating IADL dependence. The Cronbach’s alpha coefficients of ADLS and two subscales in this study were 0.814~0.894.