Table 1.

Baseline characteristics of the study sample by status of insomnia.

		Symptoms of Insomnia
Characteristics	Total (N = 22,078)	No (N = 18,431)	Yes (N = 3,647)
Age, years	59.9 ± 8.8	59.8 ± 8.8	60.6 ± 8.7
Women	13,648 (61.8)	11,153 (60.5)	2,495 (68.4)
Education
Compulsory school or below	5,604 (25.4)	4,575 (24.8)	1,029 (28.2)
High school	8,859 (40.1)	7,398 (40.1)	1,461 (40.1)
University or above	7,615 (34.5)	6,458 (35.0)	1,157 (31.7)
Depression
Seldom/never	10,078 (45.7)	9,096 (49.4)	982 (26.9)
Sometimes	10,889 (49.3)	8,725 (47.3)	2,164 (59.3)
Often/always	1,111 (5.0)	610 (3.3)	501 (13.7)
Social isolation
Seldom/never	14,205 (64.3)	12,353 (67.0)	1852 (50.8)
Sometimes	6,763 (30.6)	5,416 (29.4)	1,347 (36.9)
Often/always	1,110 (5.0)	662 (3.6)	448 (12.3)
Body mass index, kg/m 2	25.0 ± 3.4	25.0 ± 3.3	25.1 ± 3.5
Physical activity, hours/week
≤2	2,822 (12.8)	2,303 (12.5)	519 (14.2)
3–4	6,289 (28.5)	5,249 (28.5)	1,040 (28.5)
5–6	5,031 (22.8)	4,229 (23.0)	802 (22.0)
>6	7,936 (36.0)	6,650 (36.1)	1,286 (35.3)
Smoking
Never	12,533 (56.8)	10,478 (56.9)	2055 (56.4)
Former	8,162 (37.0)	6,810 (37.0)	1,352 (37.1)
Current	1,383 (6.3)	1,143 (6.2)	240 (6.6)
Alcohol consumption, g/week
≤168	18,947 (85.8)	15,808 (85.8)	3,139 (86.1)
>168	3,131 (14.2)	2,623 (14.2)	508 (13.9)
Hypertension	3,695 (16.7)	2,973 (16.1)	722 (19.8)
Diabetes	672 (3.0)	540 (2.9)	132 (3.6)
Sleep duration, hours/day
< 5	646 (2.9)	336 (1.8)	310 (8.5)
5	1,061 (4.8)	455 (2.5)	606 (16.6)
6	3,957 (17.9)	2,813 (15.3)	1,144 (31.4)
7	9,835 (44.6)	8,728 (47.4)	1,107 (30.4)
8	6,119 (27.7)	5,679 (30.8)	440 (12.1)
≥ 9	460 (2.1)	420 (2.3)	40 (1.1)

Data presented as mean ± standard deviation or N (% in column).