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. 2015 Jul 2;3:e1071. doi: 10.7717/peerj.1071

Table 1. Characteristics of the Korean middle-aged male participants by depressive symptoms.

Number (%)
Total No to moderate symptoms Severe symptoms p valuea
Characteristics n = 10,238 n = 7,470 n = 2,768
Age at enrollment y (SD) 56.3 (3.5) 56.5 (3.8) 56.2 (3.3) 0.007b
Smoking statusc Never smoker 3,027 (29.6) 2,333 (31.2) 694 (25.1) <0.001
Past smoker 2,480 (24.2) 1,783 (23.9) 698 (25.2)
Current smoker 4,730 (46.2) 3,354 (44.9) 1,377 (49.7)
Drinking status Never drinker 1,216 (11.9) 782 (10.5) 434 (15.7)
Past drinker 2,675 (26.1) 1,756 (23.5) 919 (33.2) <0.001
Current drinker 6,347 (62.0) 4,932 (66.0) 1,415 (51.1)
BMI (kg/m2) Below 18.5 323 (3.2) 160 (2.1) 163 (5.9)
18.5–22.9 4,118 (40.2) 2,843 (38.1) 1,275 (46.0) <0.001
23.0–24.9 2,992 (29.2) 2,296 (30.7) 696 (25.2)
25 or above 2,805 (27.4) 2,171 (29.1) 634 (22.9)
Marital statusc Living with spouse 9,377 (91.6) 7,060 (94.5) 2,317 (83.7) <0.001
Living without spouse 861 (8.4) 410 (5.5) 450 (16.3)
Self-rated healthc Very good or good 734 (7.2) 724 (9.7) 11 (0.4)
Fair 3,748 (36.6) 3,405 (45.6) 343 (12.4) <0.001
Poor 4,503 (44.0) 2,944 (39.4) 1,559 (56.3)
Very poor 1,253 (12.2) 398 (5.3) 856 (30.9)
Educational statusc Elementary school or below 2,407 (23.5) 1,489 (19.9) 918 (33.2)
Middle school 2,782 (27.2) 1,934 (25.9) 848 (30.6) <0.001
High school or above 5,049 (49.3) 4,048 (54.2) 1,002 (36.2)
Household income Below 1,000,000 3,450 (33.7) 1,852 (24.8) 1,597 (57.7)
per monthc 1,000,000–1,990,000 4,693 (45.8) 3,707 (49.6) 987 (35.6) <0.001
(Korean Won)d 2,000,000 or more 2,095 (20.5) 1,911 (25.6) 184 (6.7)
Participant group Survey-only group 8,233 (80.4) 5,881 (78.7) 2,352 (85.0) <0.001
Health exam group 2,005 (19.6) 1,589 (21.3) 416 (15.0)
Depressive symptoms (1)e No (0–13) 2,360 (23.0) 2,360 (31.6) 0 (0.0)
(BDI score) Mild (14–21) 2,554 (24.9) 2,554 (34.2) 0 (0.0)
Moderate (22–30) 2,556 (25.0) 2,556 (34.2) 0 (0.0) <0.001
Severe (31–39) 1,627 (15.9) 0 (0.0) 1,627 (58.8)
Extreme (40–63) 1,141 (11.1) 0 (0.0) 1,141 (41.2)
Depressive symptoms (2)f No (0–9) 1,307 (12.8) 1,307 (17.5) 0 (0.0)
(BDI score) Mild (10–16) 2,625 (25.6) 2,625 (35.1) 0 (0.0)
Moderate (17–29) 3,281 (32.0) 3,281 (43.9) 0 (0.0) <0.001
Severe (30–40) 2,015 (19.7) 257 (3.4) 1,758 (63.5)
Extreme (41–63) 1,010 (9.9) 0 (0.0) 1,010 (36.5)

Notes.

BDI
Beck Depression Inventory
BMI
body mass index
SD
standard deviation
a

Combined p-value of chi-squared analysis over multiple imputed data.

b

Combined p-value of analysis of variance over multiple imputed data.

c

Sum of the number of participants from both groups may not equal the total due to rounding of averages over multiple imputed data.

d

1,300 Korean Won was about one US dollar as of June, 2001.

e

Cut-off score based on quartiles and the last decile.

f

Cut-off score based on previous research.