Table 1.

Definition and assignment of variables in GLMM analysis.

Variable settings	Variables	Value of variables
Dependent variable	Depressive symptoms	High-risk depression = 1, low-risk depression = 0
Fixed effect variables	BADL/IADL	Limited = 1, unlimited = 0
	Sex	male = 1, female = 2
	Age (years)	60–64 = 1, 65–74 = 2, ≥75 = 3
	Household registration	Urban = 1, rural = 2
	Marital status	Married and cohabiting = 1, married but separated = 2, divorced = 3, widowed = 4, never married = 5
	Ethnic groups	Han = 1, non-Han = 2
	Education	illiteracy = 1, primary school and below = 2, elementary school and above = 3
	Income	low = 1, middle = 2, high = 3
	Type of medical insurance	Urban employees = 1, urban and rural residents = 2, free medical care = 3, commercial insurance and others = 4
	Smoking	Smoking = 1, quitting = 2, never smoking = 3
	Drinking	Drinking = 1, quitting = 2, never drinking = 3
	Chronic diseases	No chronic disease = 1, single chronic disease = 2, two or more chronic diseases = 3
	Duration of sleep (hour)	<6 = 1, 6–9 = 2, >9 = 3
	Having social activities or not	no = 0, yes = 1
	Life satisfaction	Dissatisfied = 0, satisfied = 1
	Health satisfaction	Dissatisfied = 0, satisfied = 1
	Marital satisfaction	Dissatisfied = 0, satisfied = 1
	Child relationship satisfaction	Dissatisfied = 0, satisfied = 1
	Self-reported health	Very good = 1, good = 2, fair = 3, poor = 4, very poor = 5
Random effect variables	First level	Individual
	Second level	Household
	Third level	Community