Table 1.
Description of variables used in this study.
| Type of Variables | Name and Definition of Variables | Variable Assignment |
|---|---|---|
| Demographic variables | Urban and rural areas (their Hukou status, which is a population registration system used in China that indicate individual’s rural or urban residency status. Specifically, agricultural hukou was classified as rural hukou, while non-agricultural hukou and unified residence hukou were classified as urban hukou. Hukou is a population registration system that has long been used in China. Every Chinese citizen is required to legally register in the system, as either agricultural or non-agricultural residency (normally referred to as rural vs. urban) |
Urban = 1 |
| Rural = 2 | ||
| Gender | Male = 1 | |
| Female = 2 | ||
| Age (the real age = the respondent’s birth year and month minus the interview year and month.) | 60–64 = 1 | |
| 65–74 = 2 | ||
| ≥75 = 3 | ||
| Marital status | Married and live with spouse = 1 | |
| Married but not live with spouse = 2 | ||
| Divorced = 3 | ||
| Widower = 4 | ||
| Never married = 5 | ||
| Education level (the highest level of education that the respondent attained was self-reported in CHARLS) | Illiterate = 1 | |
| Elementary school and below = 2 | ||
| Middle school = 3 | ||
| High\vocational school and above = 4 | ||
| Minorities (there are 56 ethnic groups in China, all of which are called ethnic minorities except the Han nationality) | Han = 1 | |
| Ethnic minorities = 2 | ||
| Religious belief | No = 0 | |
| Yes = 1 | ||
| Having income or not (did you receive any wage and bonus income [except pension] in the past year?) | No = 0 | |
| Yes = 1 | ||
| Health related variables | Self-reported health (would you say your health is very good, good, fair, poor or very poor?) | Very good = 1 |
| Good = 2 | ||
| Fair = 3 | ||
| Poor = 4 | ||
| Very poor = 5 | ||
| Duration of sleep (during the past month, how many hours of actual sleep did you get at night? (average hours for one night)) | ≤5 h = 1 | |
| 6–9 h = 2 | ||
| ≥10 h = 3 | ||
| Life satisfaction (How satisfied are you with your life overall? Are you completely satisfied, very satisfied, somewhat satisfied, not very satisfied, or not satisfied at all?) | Completely satisfied = 1 | |
| Very satisfied = 2 | ||
| Somewhat satisfied = 3 | ||
| Not very satisfied = 4 | ||
| Not satisfied at all =5 | ||
| Chronic disease (including hypertension, diabetes or high blood sugar, cancer or a malignant tumor, chronic lung disease such as chronic bronchitis or emphysema, heart diseases, stroke, emotional, nervous, or psychiatric problems, arthritis, dyslipidemia, liver disease, kidney disease, stomach or other digestive disease, asthma.) | Having none of these chronic disease = 0 | |
| Having one of these chronic disease = 1 | ||
| Social activities (whether they participated in the following social activities in the past month: “interacted with friend”, “played Ma-jong, chess, cards, or went to a community club”, “sent to a sporting event, participated in a social group, or participated in some other sort of club”, “took part in a community-related organization”, “took part in voluntary or charity work”, “attended an educational or training course”.) |
Having none of these social activities = 0 | |
| Having one of these social activities = 1 | ||
| Dependent variable | Depressive symptoms (recoded from continuous variable [1–30 scores], and transformed into binary variable, ≤10: negative; >10: positive) | ≤10 = 0 |
| >10 = 1 |