Suicidal Ideation Among Korean Elderly: Risk Factors and Population Attributable Fractions

Figures & data

TABLE 1. Sociodemographic and Health-Related Characteristics of Study Participants.

	No Suicidal Ideation (N = 9,682)	Suicidal Ideation (N = 1,208)	χ^2 Value	p Value
Gender			14.864	0.000
Male	3,924 (40.5)	420 (34.8)
Female	5,758 (59.5)	788 (65.2)
Age			4.929	0.295
65–69 years	2,286 (23.6)	295 (24.4)
70–74 years	2,969 (30.7)	392 (32.5)
75–79 years	2,568 (26.5)	315 (26.1)
80–84 years	1,266 (13.1)	147 (12.2)
85+ years	593 (6.1)	59 (4.8)
Marital status			44.912	0.000
Married	6,015 (62.1)	630 (52.2)
Single/widowed/divorced	3,667 (37.9)	578 (47.8)
Educational status			17.885	0.000
No education	3,460 (35.7)	504 (41.7)
6 years or less	3,510 (36.3)	410 (33.9)
7–12 years	2,223 (23.0)	246 (20.4)
13 years or more	489 (5.0)	48 (4.0)
Current employment status			57.490	0.000
Yes	3,366 (34.8)	288 (23.8)
No	6,316 (65.2)	920 (76.2)
Economic status			102.699	0.000
1st quintile	2,260 (23.3)	425 (35.2)
2nd quintile	2,055 (21.2)	267 (22.1)
3rd quintile	1,895 (19.6)	206 (17.2)
4th quintile	1,806 (18.7)	186 (15.4)
5th quintile	1,666 (17.2)	124 (10.3)
Religion			0.042	0.839
Yes	6,279 (64.9)	787 (65.2)
No	3,403 (35.1)	421 (34.8)
Social support			58.730	0.000
More than one person	7,980 (82.4)	886 (73.3)
No	1,700 (17.6)	322 (26.7)
Body mass index			1.640	0.200
Normal	6,381 (66.4)	812 (68.2)
Over or underweight	3,232 (33.6)	378 (31.8)
Currently smoking			17.558	0.000
No	8,541 (88.2)	1,015 (84.0)
Yes	1,141 (11.8)	193 (16.0)
Alcohol use			8.562	0.003
No	6,620 (68.4)	876 (72.5)
Yes	3,061 (31.6)	332 (27.5)
Sleep duration			142.612	0.000
6–9 hours	7,241 (74.8)	708 (58.6)
Other	2,441 (25.2)	500 (41.4)
Exercise			8.248	0.004
Yes	4,728 (48.8)	537 (44.4)
No	4,954 (51.2)	671 (55.6)
Chronic illness			84.993	0.000
0–1	2,869 (29.6)	205 (17.0)
More than 2	6,813 (70.4)	1,003 (83.0)
Subjective health status			204.476	0.000
Good, fair	5,405 (55.8)	411 (34.1)
Poor	4,277 (44.2)	796 (65.9)
Functional impairment			98.373	0.000
No	8,490 (87.8)	935 (77.5)
Yes	1,183 (12.2)	272 (22.5)
Cognitive impairment			3.287	0.070
No	6,275 (79.1)	772 (76.7)
Yes	1,654 (20.9)	235 (23.3)
Depression			801.611	0.000
No	6,976 (72.1)	382 (31.7)
Yes	2,696 (27.9)	824 (68.3)

Note. All values are unweighted N (%), unless indicated, to give descriptive statistics on the characteristics of the study sample rather than nationally generalizable estimates. Total unweighted numbers of each variable are 10,890, except some variables such as social support (10,888), body mass index (10,803), alcohol use (10,889), subjective health status (10,889), functional impairment (10,880), cognitive impairment (8,936), and depression (10,878). Unweighted chi-square test was used for categorical variables. Information on their body mass index (BMI) includes underweight (BMI < 18.5), normal (18.5 ≤ BMI < 25), and overweight (BMI ≥ 25). “Other” for sleep duration indicate sleep duration less than six hrs per day and more than nine hrs per day.

TABLE 2. Risk Factors for Suicidal Ideation

	N	B (SE)	cOR (95% CI)	p	B (SE)	aOR (95% CI)	p
Gender
Male	4,344		1			1
Female	6,546	0.24 (0.09)	1.27 (1.07–1.50)	0.007	0.09 (0.14)	1.09 (0.83–1.43)	0.539
Age
60–64 years	2,581		1			1
70–74 years	3,361	0.09 (0.11)	1.10 (0.89–1.36)	0.389	−0.19 (0.13)	0.83 (0.65–1.07)	0.151
75–79 years	2,883	0.03 (0.12)	1.03 (0.82–1.30)	0.783	−0.42 (0.14)	0.66 (0.50–0.87)	0.003
80–84 years	1,413	−0.09 (0.14)	0.91 (0.69–1.21)	0.524	−0.65 (0.17)	0.52 (0.37–0.74)	0.000
85+ years	652	−0.46 (0.19)	0.63 (0.44–0.92)	0.017	−1.13 (0.24)	0.32 (0.20–0.52)	0.000
Marital status
Married	6,645		1			1
Nonmarried	4,245	0.39 (0.08)	1.47 (1.26–1.73)	0.000	0.19 (0.12)	1.21 (0.95–1.54)	0.115
Education
No education	3,964		1			1
6 years or less	3,920	−0.31 (0.09)	0.73 (0.61–0.88)	0.001	−0.01 (0.12)	0.99 (0.79–1.25)	0.949
7–12 years	2,469	−0.23 (0.11)	0.80 (0.64–0.99)	0.039	0.23 (0.15)	1.26 (0.94–1.70)	0.126
13 years or more	537	−0.39 (0.22)	0.68 (0.44–1.04)	0.076	0.63 (0.28)	1.87 (1.08–3.23)	0.025
Current employment status
Yes	3,654		1			1
No	7,236	0.54 (0.09)	1.72 (1.43–2.07)	0.000	0.21 (0.12)	1.24 (0.98–1.56)	0.070
Economic status
1st quintile	2,685		1			1
2nd quintile	2,322	−0.38 (0.11)	0.68 (0.55–0.84)	0.000	−0.26 (0.13)	0.77 (0.59–1.00)	0.051
3rd quintile	2,101	−0.48 (0.12)	0.62 (0.49–0.79)	0.000	−0.10 (0.14)	0.91 (0.68–1.20)	0.489
4th quintile	1,992	−0.55 (0.13)	0.58 (0.45–0.74)	0.000	−0.22 (0.16)	0.80 (0.59–1.09)	0.162
5th quintile	1,790	−0.96 (0.14)	0.38 (0.29–0.51)	0.000	−0.52 (0.17)	0.59 (0.42–0.83)	0.003
Religion
Yes	7,066		1			1
No religion	3,824	−0.10 (0.09)	0.91 (0.76–1.07)	0.250	−0.10 (0.10)	0.90 (0.74–1.10)	0.315
Social support
More than one person	8,866		1			1
No	2,022	0.53 (0.09)	1.70 (1.41–2.04)	0.000	0.25 (0.11)	1.28 (1.03–1.59)	0.028
Body mass index
Normal	7,193		1			1
Over or underweight	3,610	−0.02 (0.09)	0.98 (0.82–1.17)	0.842	−0.06 (0.11)	0.94 (0.76–1.16)	0.547
Currently smoking
No	9,556		1			1
Yes	1,334	0.25 (0.11)	1.28 (1.03–1.61)	0.029	0.35 (0.14)	1.42 (1.08–1.88)	0.014
Alcohol use
No	7,496		1			1
Yes	3,393	−0.19 (0.09)	0.83 (0.69–1.00)	0.046	0.19 (0.12)	1.20 (0.95–1.52)	0.118
Sleep duration
6–9 hours	7,949		1			1
Other	2,941	0.79 (0.08)	2.20 (1.87–2.60)	0.000	0.56 (0.10)	1.74 (1.44–2.12)	0.000
Exercise
Yes	5,265		1			1
No	5,625	0.21 (0.08)	1.24 (1.05–1.46)	0.010	−0.13 (0.10)	0.88 (0.72–1.08)	0.219
Chronic illness
0–1	3,074		1			1
More than 2	7,816	0.81 (0.11)	2.25 (1.83–2.77)	0.000	0.34 (0.14)	1.40 (1.08–1.84)	0.013
Subjective health status
Good, fair	5,816		1			1
Poor	5,073	1.01 (0.09)	2.74 (2.31–3.25)	0.000	0.44 (0.12)	1.56 (1.24–1.97)	0.000
Functional impairment
No	9,425		1			1
Yes	1,455	0.78 (0.10)	2.18 (1.79–2.65)	0.000	0.37 (0.13)	1.45 (1.12–1.87)	0.005
Cognitive impairment
No	7,047		1			1
Yes	1,889	0.15 (0.11)	1.16 (0.94–1.43)	0.165	−0.14 (0.12)	0.87 (0.69–1.11)	0.256
Depression
No	7,358		1			1
Yes	3,520	1.75 (0.09)	5.75 (4.83–6.85)	0.000	1.48 (0.11)	4.36 (3.55–5.37)	0.000

Notes. cOR = crude odd ratio; aOR = adjusted odd ratio; All logistic regressions are weighted to reflect sampling design. Total unweighted numbers for each variable in the analysis for cOR are the same presented in Table 1. Total weighted number for the analysis for aOR is 8,842. OR = 1 indicates for reference level of the applicable variable. Information on their body mass index (BMI) includes underweight (BMI < 18.5), normal (18.5 ≤ BMI < 25), and overweight (BMI ≥ 25 kg/m²). “Other” for sleep duration indicate sleep duration less than 6 hrs per day and more than 9 hrs per day.

FIGURE 1. The adjusted odds ratio of suicidal ideation according to various sociodemographic and health-related variables, functional impairment, cognitive impairment, and depression (total weighted n = 8,842). Notes. ES = economic status; The dots indicate the adjusted odds ratio presented in Table 2 and the whiskers indicate the 95% CI. Reference category for each independent variable are gender (male), age (60–64 years), marital status (married), no education, current employment status (yes), economic status (1st quintile), has religion, social support (more than one person), normal BMI, not currently smoking, no alcohol use, sleep duration (6–9 hours), chronic illness (0–1), subjective health status (good, fair), no functional impairment, no cognitive impairment, and no depression. Information on their body mass index (BMI) includes underweight (BMI < 18.5), normal (18.5 ≤ BMI < 25), and overweight (BMI ≥ 25). Sleep abnormality indicates sleep duration less than six hours per day and more than nine hours per day.)

TABLE 3. Population Attributable Fraction of Suicidal Ideation

	PT	PD	Crude PAF*	Adjusted PAF^†	Adjusted PAF (95% CI)^‡
Poor social support	18.6%	26.7%	0.114	0.058	0.042 (0.003–0.081)
Currently smoking	12.2%	16.0%	0.033	0.047	0.036 (0.006–0.065)
Sleep abnormality	27.0%	41.4%	0.245	0.177	0.141 (0.088–0.190)
Chronic illness (≥ 2)	71.8%	83.0%	0.473	0.239	0.194 (0.038–0.325)
Poor subjective health	46.6%	65.9%	0.448	0.236	0.189 (0.089–0.277)
Functional impairment	13.4%	22.5%	0.136	0.070	0.049 (0.014–0.084)
Depression	30.3%	68.3%	0.605	0.526	0.457 (0.395–0.513)

Notes. *Crude PAF = P_T (ORc − 1) / [1 + P_T (OR_C − 1)], where P_T is the prevalence of the risk factor in the total sample, OR_C is the crude OR (Levin, 1953); ^†adjusted PAF = P_D [(Ora − 1) / ORa], where P_D is the prevalence of exposure among cases of disease, ORa is the OR adjusted for confounding factors (Rockhill et al., 1998), ^‡adjusted PAF (95% CI), punaf essentially implements the method for estimating PAFs recommended by Greenland and Drescher (1993) for cohort and cross-sectional studies. The calculation of a PAF is based on the applicable ORc and ORa in Table 2. Sleep abnormality indicates sleep duration less than six hours per day and more than nine hours per day.

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