Association Between Sleep Quality and Falls: A Nationwide Population-Based Study from South Korea

Figures & data

Table 1 Baseline Characteristics of the Fallers and Non-Fallers

	Fallers (n = 2499)	Non-Fallers (n = 199,201)	p-value
Age (y)	59.6 ± 17.5	53.1 ± 17.0	<0.001
Sex
Male	908 (36.3)	93,059 (46.7)	<0.001
Female	1591 (63.7)	106,142 (53.3)
Body mass index (kg/m^2)	23.7 ± 3.5	23.7 ± 3.4	0.897
Residence area
Urban	1367 (54.7)	117,460 (59.0)	<0.001
Rural	1132 (45.3)	81,741 (41.0)
Education			<0.001
Elementary school or lower	899 (36.0)	40,651 (20.4)
Middle school	373 (14.9)	23,069 (11.6)
High school	597 (23.9)	59,688 (30.0)
College or higher	630 (25.2)	75,793 (38.0)
Marital status			<0.001
Married (living with spouse)	1529 (61.2)	137,046 (68.8)
Living alone (never married,  separated, divorced, widowed)	970 (38.8)	62,155 (31.2)
Employment status			<0.001
Employed	1276 (51.1)	126,565 (63.5)
Unemployed	1223 (48.9)	72,636 (36.5)
Household income			<0.001
Low	1000 (40.0)	52,147 (26.2)
Middle low	693 (27.7)	56,522 (28.4)
Middle high	490 (19.6)	55,917 (28.1)
High	316 (12.6)	34,615 (17.4)
Smoking			0.004
Current smoker	399 (16.0)	35,925 (18.0)
Non-smoker, ex-smoker	2100 (84.0)	163,276 (82.0)
Risky drinker			<0.001
Yes	571 (22.8)	55,618 (27.9)
No	1928 (77.2)	143,583 (72.1)
Regular exercise			<0.001
Yes	1016 (40.7)	90,471 (45.4)
No	1483 (59.3)	108,730 (54.6)
Hypertension			<0.001
Yes	900 (36.0)	53,032 (26.6)
No	1599 (64.0)	146,169 (73.4)
Diabetes mellitus			<0.001
Yes	384 (15.4)	21,154 (10.6)
No	2115 (84.6)	178,047 (89.4)
Subjective cognitive decline			<0.001
Yes	681 (27.3)	34,860 (17.5)
No	1818 (72.7)	164,341 (82.5)
Perceived stress			<0.001
Yes	677 (27.1)	46,602 (23.4)
No	1822 (72.9)	152,599 (76.6)
Perceived health status			<0.001
Good	596 (23.8)	72,736 (36.5)
Moderate	1030 (41.2)	90,015 (45.2)
Bad	873 (34.9)	36,450 (18.3)
PHQ-9 global score	3.4 ± 4.3	2.1 ± 3.1	<0.001
Depression			<0.001
Yes (PHQ9 score ≥ 10)	209 (8.4)	6709 (3.4)
No (PHQ9 score 0–9)	2290 (91.6)	192,492 (96.6)

Note: Data are presented as number (percent) or mean ± standard deviation.

Abbreviation: PHQ-9, Patient Health Questionnaire-9.

Table 2 Comparisons of the PSQI Scores Between Fallers and Non-Fallers

	Fallers (n = 2499)	Non-Fallers (n = 199,201)	p-value
PSQI global score	5.8 ± 3.4	4.7 ± 2.9	<0.001
Good sleep (PSQI ≤ 5)	1400 (56.0)	139,704 (70.1)	<0.001
Poor sleep (PSQI > 5)	1099 (44.0)	59,497 (29.9)
Sleep quality			<0.001
0: very good	278 (11.1)	29,376 (14.7)
1: fairly good	1357 (54.3)	124,934 (62.7)
2: fairly bad	705 (28.2)	38,395 (19.3)
3: very bad	159 (6.4)	6496 (3.3)
Sleep latency (score)			<0.001
0: 0	926 (37.1)	91,978 (46.2)
1: 1–2	706 (28.3)	59,184 (29.7)
2: 3–4	447 (17.9)	27,061 (13.6)
3: 5–6	420 (16.8)	20,978 (10.5)
Sleep duration (h)			<0.001
0: > 7	463 (18.5)	35,400 (17.8)
1: 6–7	1228 (49.1)	113,708 (57.1)
2: 5–6	453 (18.1)	32,613 (16.4)
3: < 5	355 (14.2)	17,480 (8.8)
Sleep efficiency (%)			<0.001
0: ≥ 85	2163 (86.6)	183,623 (92.2)
1: 75–84	234 (9.4)	11,420 (5.7)
2: 65–74	66 (2.5)	2589 (1.3)
3: ≤ 65	36 (1.4)	1569 (0.8)
Sleep disturbance (score)			<0.001
0: 0	227 (9.1)	35,458 (17.8)
1: 1–9	1661 (66.5)	138,882 (69.7)
2: 10–18	574 (23.0)	23,959 (12.0)
3: 19–27	37 (1.5)	902 (0.5)
Use of sleeping medication			<0.001
0: not during the past month	2318 (92.8)	191,273 (96.0)
1: less than once a week	46 (1.8)	2112 (1.1)
2: once or twice a week	38 (1.5)	1633 (0.8)
3: three or more times a week	97 (3.9)	4183 (2.1)
Daytime dysfunction			<0.001
0: very good	1550 (62.0)	136,814 (68.7)
1: fairly good	547 (21.9)	40,672 (20.4)
2: fairly bad	323 (12.9)	18,238 (9.2)
3: very bad	79 (3.2)	3477 (1.7)

Note: Data are presented as number (percent) or mean ± standard deviation.

Abbreviation: PSQI, Pittsburgh Sleep Quality Index.

Table 3 Results of Multivariable Logistic Regression Analysis Showing Associations Between the PSQI Scores and the Risk of Falls

	Model 1		Model 2		Model 3
	OR	95% CI	OR	95% CI	OR	95% CI
PSQI
Good sleep (PSQI ≤ 5)	1	Reference	1	Reference	1	Reference
Poor sleep (PSQI > 5)	1.62	1.49–1.76	1.53	1.41–1.66	1.30	1.19–1.42
Subjective sleep quality
0–1	1	Reference	1	Reference	1	Reference
2–3	1.25	1.13–1.39	1.23	1.11–1.36	1.11	1.00–1.23
Sleep latency
0–1	1	Reference	1	Reference	1	Reference
2–3	1.09	0.99–1.21	1.06	0.95–1.17	1.04	0.94–1.15
Sleep duration
0–1	1	Reference	1	Reference	1	Reference
2–3	1.22	1.16–1.28	1.15	1.10–1.21	1.14	1.09–1.20
Sleep efficiency
0–1	1	Reference	1	Reference	1	Reference
2–3	1.07	0.87–1.33	1.04	0.84–1.29	1.01	0.81–1.26
Sleep disturbance
0–1	1	Reference	1	Reference	1	Reference
2–3	1.47	1.32–1.64	1.43	1.28–1.59	1.30	1.16–1.46
Use of sleeping medication
0–1	1	Reference	1	Reference	1	Reference
2–3	1.06	0.88–1.27	1.02	0.85–1.23	0.94	0.78–1.13
Daytime dysfunction
0–1	1	Reference	1	Reference	1	Reference
2–3	1.32	1.18–1.48	1.31	1.17–1.47	1.21	1.08–1.13

Notes: Model 1 was adjusted for sex, age, and body mass index; Model 2 was adjusted for Model 1 variables and socioeconomic variables (residence area, education level, marital status, employment status, and household income); Model 3 was adjusted for Model 2 variables and physical health-related variables (risky drinking, smoking, regular exercise, hypertension, and diabetes mellitus) and mental health-related variables (perceived status of health, perceived level of stress, subjective cognitive decline, and depression).

Abbreviations: CI, confidence interval; OR, odds ratio; PSQI, Pittsburgh Sleep Quality Index.

Table 4 Results of Subgroup Analyses by Age Showing Associations Between the PSQI Scores and the Risk of Falls

	Young Adult (n = 48,466)		Middle-Aged Adult (n = 75,737)		Older Adult (n = 77,497)		p-value
Age (range, y)	30.1 ± 6.2 (19–39)		50.2 ± 5.8 (40–59)		70.5 ± 7.5 (≥ 60)		<0.001
Male/female	23,148/25,318		35,032/40,705		35,787/41,710		<0.001
Fallers	397 (0.8)		700 (0.9)		1402 (1.8)		<0.001
PSQI global score	4.4 ± 2.7		4.5 ± 2.7		5.2 ± 3.1
Good sleep (PSQI ≤5)	35,486 (73.2)		55,575 (73.4)		50,043 (64.6)		<0.001
Poor sleep (PSQI >5)	12,980 (26.8)		20,162 (26.6)		27,454 (35.4)		<0.001
	OR	95% CI	OR	95% CI	OR	95% CI
Model 1
Good sleep (PSQI ≤5)	1	Reference	1	Reference	1	Reference
Poor sleep (PSQI >5)	1.42	1.15–1.75	1.76	1.51–2.05	1.54	1.39–1.72
Model 2
Good sleep (PSQI ≤5)	1	Reference	1	Reference	1	Reference
Poor sleep (PSQI >5)	1.36	1.10–1.67	1.64	1.41–1.92	1.49	1.34–1.66
Model 3
Good sleep (PSQI ≤5)	1	Reference	1	Reference	1	Reference
Poor sleep (PSQI >5)	1.29	1.03–1.61	1.44	1.22–1.71	1.26	1.13–1.42

Notes: Data are presented as number (percent) or mean ± standard deviation. Group comparisons were made using one-way ANOVA or chi-square test, where appropriate; Model 1 was adjusted for sex, age, and body mass index; Model 2 was adjusted for Model 1 variables and socioeconomic variables (residence area, education level, marital status, employment status, and household income); Model 3 was adjusted for Model 2 variables and physical health-related variables (risky drinking, smoking, regular exercise, hypertension, and diabetes mellitus) and mental health-related variables (perceived status of health, perceived level of stress, subjective cognitive decline, and depression).

Abbreviations: CI, confidence interval; OR, odds ratio; PSQI, Pittsburgh Sleep Quality Index.