International Journal of
Environmental Research
and Public Health
Article
Associations between Sleep Quality, Frailty, and Quality of Life
among Older Adults in Community and Nursing Home Settings
Mateja Lorber 1 , Sergej Kmetec 1, *, Adam Davey 2 , Nataša Mlinar Reljić 1 , Zvonka Fekonja 1
and Barbara Kegl 1
1
2
*
Faculty of Health Sciences, University of Maribor, Zitna Ulica 15, 2000 Maribor, Slovenia
College of Health Sciences, University of Delaware, 210 South College Avenue, Newark, NJ 19716, USA
Correspondence: sergej.kmetec1@um.si; Tel.: +386-23004751
Abstract: Poor sleep quality is prevalent among older adults, but limited data document associations
between frailty and quality of life comparing individuals living in the community with those in
nursing homes. This cross-sectional study (conducted between August and November 2019) included
831 older adults (mean age 76.5 years) from Slovenia’s community and nursing home settings.
The results showed comorbidity in 38% of community-dwelling older adults and 31% of older adults
in nursing homes. The prevalence of frailty among community-dwelling older adults was 36.5%,
and among older adults in a nursing home was 58.5%. A total of 76% of community-dwelling older
adults and 95.8% of nursing home residents reported poor sleep quality. Sleep quality and frailty
predict 42.3% of the total variability of quality of life for older adults in nursing homes and 34.8% for
community-dwelling older adults. The study’s results indicate that the quality of life can be affected
by factors (e.g., worse sleep quality and frailty) among older adults, regardless of being a resident
or from the community. Understanding how sleep quality is affected by social, environmental, and
biological factors can help improve sleep quality and potentially the quality of life of older adults.
Keywords: sleep quality; frailty; quality of life; older adults; nursing homes; community-dwelling
Citation: Lorber, M.; Kmetec, S.;
Davey, A.; Mlinar Reljić, N.; Fekonja,
Z.; Kegl, B. Associations between
Sleep Quality, Frailty, and Quality of
1. Introduction
Life among Older Adults in
Frailty is a common old-age syndrome with significant implications for public health [1]
and has emerged as a major public health concern [2] and is important when considering
financial healthcare planning [3]. Frailty represents a loss of physiological reserve and resistance to stressors due to cumulative declines across multiple physiological systems [4,5].
As a result, it makes older people more vulnerable to poor health outcomes [2]. Increasing
life expectancy brings opportunities for older adults, their families, and societies [6], but
a greater emphasis should be placed on identifying risk factors to avoid or reduce frailty
in older adults—especially those with one or more chronic diseases [7]. The prevalence
of frailty is much higher among older adults living in nursing homes than in community
settings, and it is a significant predictor of mortality among older adults in nursing homes.
Frailty in older adults is associated with sleep quality. Poor sleep quality is prevalent
among older adults and is compounded by frailty, significantly correlating with poor
sleep quality in older adults living in nursing homes [8,9]. Algahtani 2021 demonstrated
a significant association between frailty and poor sleep quality in older adults living in
a community-dwelling sample with chronic diseases. In addition to the physiological
changes of aging, sleep quality in old age is also affected by chronic diseases, which
are increasingly prevalent with age [10]. The results in 15 European countries between
2004 and 2017 showed considerable variability in the prevalence of comorbidity in adults
aged 50. The prevalence of comorbidity increases between the first and second waves of
research. In Slovenia in 2017, the rate of comorbidity was about 40%; the lowest percentage
(approximately 30%) was in The Netherlands, Switzerland, and Sweden. In all other
Community and Nursing Home
Settings. Int. J. Environ. Res. Public
Health 2023, 20, 4937. https://
doi.org/10.3390/ijerph20064937
Academic Editors: Kneginja Richter
and Antje Büttner-Teleagă
Received: 16 January 2023
Revised: 3 March 2023
Accepted: 8 March 2023
Published: 10 March 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Int. J. Environ. Res. Public Health 2023, 20, 4937. https://doi.org/10.3390/ijerph20064937
https://www.mdpi.com/journal/ijerph
Int. J. Environ. Res. Public Health 2023, 20, 4937
2 of 12
European countries, the rate was higher than 40%, up to 55%. In all countries, the percentage
of comorbidity increases with age [11]. The rate of comorbidity is much higher in the
United States (62.5%) [12]. A growing body of research indicates that insufficient sleep
may also increase the risk of several conditions and chronic diseases, including diabetes,
cardiovascular disease, obesity, and depression [13]. Decreasing sleep quality can result
from several factors, such as physiological changes in age, underlying physical conditions,
and psychosocial factors [14]. Poor sleep quality can harm older adults’ physical and mental
health and daytime functioning [15,16]. Some studies indicate more than half of older
adults have sleep problems [17], and 5–8% of older adults experience insomnia [18]. Sleep
disorders indicate the possibility of disturbances in circadian rhythms in chronic diseases,
which significantly worsen the quality of life [19]. In an aging population, multimorbidity
has been identified as a big challenge for patients and health systems worldwide [20].
Andersen’s behavioral model [21] was used for factors associated with older adults’
quality of life. The model includes contextual and individual characteristics, including
demographics, social, human, and material resources, and factors such as several chronic
conditions. Health behaviors include physical activity and support. The decline in one or
more of a person’s abilities is associated with reductions in quality of life [22].
According to the literature review, only the association between sleep quality and
quality of life or frailty and quality of life has been investigated so far, and this research included only community-dwelling elderly. Because until now there has been no research that
included all three variables, we investigated the association between sleep quality, frailty,
and quality of life among community-dwelling older adults and nursing home residents.
2. Materials and Methods
2.1. Study Design
This study is based on a cross-sectional approach by using a questionnaire. We followed the STROBE checklist for reporting cross-sectional studies [23] for rigorous reporting
of the study results.
2.2. Setting and Participants
This study used convenience sampling to invite older adults into nursing homes and
community dwellings in the northeastern part of Slovenia. The inclusion criteria for the
sample were older adults (65+ years) living in nursing homes or community dwellings and
cognitive functioning appropriate to complete the survey (cognitive ability was assessed
so that the healthcare professional considered which participants could participate in the
study. In doing so, they looked at the absence of known organic or psychiatric affecting
cognitive ability). There were no exclusion criteria. The sample size was calculated (using
the Cochran formula) to allow the detection of clinically meaningful associations, i.e.,
R2 ≥ 0.02 within each group, which suggested n = 387 (e = 95%; z = 5%) in each setting.
2.3. Data Collection and Analysis
Participants completed the Pittsburgh Sleep Quality Index (PSQI) [24], the Tilburg
Frailty Indicator (TFI) [25], the Quality of life self-assess question on a five-point Likert scale
(from 1 “very poor” to 5 “very good”) and 11 demographic and personal questionnaires
(demographics, physical activity, chronic disease, income, social interaction, support, etc.).
PSQI is a 19-item questionnaire measuring sleep quality and quantity among adults.
This questionnaire consists of seven domains (subjective sleep quality, sleep latency, duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime
dysfunction). Overall scores range from 0 to 21. A higher score indicates poorer sleep
quality and a high level of sleep disorders. A global score ≥ 5 indicates clinically significant
sleep impairment [24].
TFI is a 15-item questionnaire measuring frailty among older adults. TFI consists of
three components (physical, psychological, and social components). Total scores range
from 0 to 15 [25], with total scores ≥ 5 points indicating frailty [25,26].
Int. J. Environ. Res. Public Health 2023, 20, 4937
3 of 12
Data were collected from August to November 2019 in Slovenian nursing homes and
the local community in the northeastern part of Slovenia based on prior ethical approval
and written permission from participating community registered nurses who assisted
us with preventive or curative visits to include older adults living in the community.
Of the 2000 paper-based questionnaires distributed, 872 were returned. After removing
41 questionnaires because of missing data, we had 831 questionnaires fully completed for
further analysis (response rate was 41.5%).
Continuous variables are presented as means (M) and standard deviations (SD) (normally distributed) or as median (Mdn) with interquartile range (IQR) (not normally distributed). Categorical variables were presented as frequencies and percentages. The Shapiro–
Wilk test was used to check the normality distribution of variables. Mann–Whitney U tests
compared participant groups’ mean scores for continuous or ordinal variables. Correlations
between sleep quality, frailty, and quality of life regarding the participant group were
checked with Spearman’s correlation coefficient [27]. All analyses use α = 0.05 to determine
statistical significance. All three questionnaires showed acceptable internal validity as the
Cronbach α coefficient exceeded our desired threshold of 0.70 [28].
2.4. Ethical Considerations
Ethical review and approval were obtained (Ref.: 038/2018/2510-1/504). We also
obtained permission from the nursing homes and individual participants to conduct the
study. Participants in the study were informed in writing of the purpose and objectives,
confidentiality, anonymity, and voluntary withdrawal from participation before submitting
the questionnaire. The study strictly adheres to the ethical principles of the Declaration of
Helsinki [29] and the Oviedo Convention provisions [30].
3. Results
The study included 831 participants, mostly women (66.5%; n = 553), with a mean
age of 76.5 years (SD = 1.6). Similarly, a higher percentage of participants from nursing
homes (70%; n = 231) and the community (64.3%; n = 322) were female. On average,
participants from nursing homes were 79.0 years old (SD = 9.0), and the mean age in
community dwellings was 74.9 years (SD = 9.5). Modal relationship status was widowed
overall (50. 7%; n = 421); 71.2% (n = 235) of nursing home residents were widowed, whereas
42. 9% (n = 215) of community residents were married. Most commonly, participants had
completed secondary education overall (54.5%; n = 453), as well as in nursing homes (46.1%;
n = 152) and the community (60.1%; n = 301). Overall, 280 participants took medication
for sleep disorders. One hundred and fifty participants regularly took medication for
insomnia, and 130 participants took it less than once a week. Most participants had one
chronic disease overall (52.2%; n = 434), in nursing homes (47.9%; n = 158), and in the
community (55.1%; n = 276). Two to three chronic diseases accounted for the second largest
percentage regarding the number of chronic diseases (Overall: 31.5%; n = 262; Nursing
homes: 37%; n = 122; Community: 27.9%; n = 140). Most participants overall had at least
one chronic disease (65.2%; n = 542), as did participants in nursing homes (73.6%; n =
243) and participants in the community (59.7%; n = 299). Overall, 77.5% (n = 611) of
participants were satisfied with their living environment, as well as in nursing homes
(69.4%; n = 229) and the community (76.2%; n = 382) (Table 1). Among chronic diseases,
most had arterial hypertension (n = 497), followed by diabetes (n = 327), asthma (n = 68)
and chronic obstructive pulmonary disease (n = 6).
Int. J. Environ. Res. Public Health 2023, 20, 4937
4 of 12
Table 1. Demographic variables and their relationship with sleep quality, frailty and quality of life.
Descriptive Statistics
Sleep Quality (Total)
Frailty (Total)
Quality of Life (Total)
Total
(n = 831)
Nursing Home
(n = 330)
Community
(n = 501)
Nursing Home
(n = 330)
M ± SD; Mdn(IQR)
Community
(n = 501)
M ± SD; Mdn(IQR)
Nursing Home
(n = 330)
M ± SD; Mdn(IQR)
Community
(n = 501)
M ± SD; Mdn(IQR)
Nursing Home
(n = 330)
M ± SD; Mdn(IQR)
Community
(n = 501)
M ± SD; Mdn(IQR)
Gender %(n)
—
—
—
U = 11,265.5,
p = 0.831
U = 21,255.5,
p < 0.001
U = 8331.0,
p < 0.001
U = 24,499.5,
p = 0.005
U = 9659.0;
p = 0.020
U = 28,792.0;
p = 0.985
Male
33.5(278)
30(99)
35.7(179)
9.91 ± 3.23;
10.0(7–13)
5.93 ± 2.39;
5.0(4–8)
9.91 ± 3.23;
4.0(3–6)
3.83 ± 3.08;
3.0(2–5)
3.35 ± 0.94;
3.0(3–4)
3.52 ± 0.93;
4.0(3–4)
Female
66.5(553)
70(231)
64.3(322)
10.04 ± 3.80;
10.0(7–12)
7.34 ± 3.26;
7.0(5–10)
10.04 ± 3.63;
6.0(4–8)
4.59 ± 3.15;
4.0(2–7)
3.04 ± 1.09;
3.0(2–4)
3.50 ± 0.96;
4.0(3–4)
Age
(Y; M ± SD; R)
76.5 ± 1.5
(66–99)
79 ± 9.04
(67–99)
74.9 ± 9.48 (65–97)
rs = −0.085;
p = 0.124
rs = 0.227; p < 0.001
rs = 0.310; p < 0.001
rs = 0.250; p < 0.001
rs = 0.054;
p = 0.324
rs = 0.067;
p = 0.137
Relationship Status %(n)
—
—
—
χ2 (4) = 27.123; p < 0.001
χ2 (4) = 75.123; p < 0.001
χ2 (4) = 16.038;
p = 0.003
χ2 (4) = 69.166; p < 0.001
χ2 (4) = 11.606;
p = 0.021
χ2 (4) = 25.534; p < 0.001
4.87 ± 1.99;
5.0(3–5)
4.36 ± 2.61;
4.0(3–5.75)
2.98 ± 1.76;
3.0(2–3)
3.53 ± 0.81;
4.0(3–4)
3.81 ± 0.68;
4.0(3–4)
Variables
Single
10(83)
10.9(36)
9.4(47)
8.25 ± 2.77;
7.50(6.25–10)
Married
29.5(245)
9.1(30)
42.9(215)
8.67 ± 2.23;
8.5(7–10.25)
6.42 ± 2.67;
6.0(5–8)
5.70 ± 2.93;
5.0(3–9)
3.67 ± 3.02;
3.0(1–5)
3.33 ± 0.88;
3.0(3–4)
3.61 ± 0.95;
4.0(3–4)
Divorced
5.9(49)
7.3(24)
5(25)
9.08 ± 3.08;
10.0(6.25–11.75)
4.52 ± 1.66;
4.0(3–6)
5.38 ± 3.24;
5.5(2–7.75)
3.04 ± 1.24;
3.0(2–4)
3.29 ± 0.91;
3.0(3–4)
3.84 ± 0.80;
4.0(3–4)
Cohabitation
4(33)
1.5(5)
5.6(28)
6 ± 2.24;
5.0(5–7.50)
7.25 ± 3.00;
6.5(5–10)
3.00 ± 1.23;
3.0(2–4)
2.86 ± 2.51;
2.0(1.25–3)
3.60 ± 1.14;
4.0(2.5–4.5)
3.39 ± 0.88;
3.5(3–4)
Widowed
50.7(421)
71.2(235)
37.1(186)
10.62 ± 3.78;
11.0(8–13)
8.06 ± 3.30;
8.0(6–10)
5.80 ± 2.60;
6.0(4–7)
5.81 ± 3.24;
5.0(3–9)
3.02 ± 1.11;
3.0(2–4)
3.28 ± 0.99;
3.0(3–4)
Education %(n)
—
—
—
χ2 (2) = 29.259; p < 0.001
χ2 (2) = 4.669;
p = 0.097
χ2 (2) = 0.510;
p = 0.775
χ2 (2) = 18.059; p < 0.001
χ2 (2) = 6.512;
p = 0.039
χ2 (2) = 15.534; p < 0.001
Elementary education
36.1(300)
45.8(151)
29.7(149)
11.13 ± 3.51;
10.9(8–13)
7.91 ± 2.82;
7.1(4.50–9)
5.72 ± 2.73;
5.1(4–7)
4.89 ± 3.06;
4.1(2–7)
3.33 ± 0.873;
3.1(2–4)
3.37 ± 0.96;
4.4(3–4)
Secondary Education
54.5(453)
46.1(152)
60.1(301)
10.82 ± 3.45;
11.0(8–13)
7.05 ± 3.09;
7.0(4.50–9)
5.63 ± 2.73;
5.0(4–7)
4.85 ± 3.25;
4.0(2–7)
3.02 ± 1.06;
3.0(2–4)
3.37 ± 0.96;
4.0(3–4)
HE (Bachelor)
8.5(71)
7.9(26)
9(45)
8.69 ± 3.69;
8.0(6–11)
6.59 ± 2.86;
6.0(5–8)
5.51 ± 2.69;
5.0(3.75–8)
3.75 ± 2.84;
3.0(2–5)
3.31 ± 1.06;
3.0(3–4)
3.68 ± 0.89;
4.0(3–4)
HE (Master or Doctoral)
0.8(7)
0.3(1)
1.2(6)
8.33 ± 2.52;
8.0(6–10.25)
6.67 ± 3.69;
6.0(4–8)
5.0 ± 2.66;
5.5(2.75–6.25)
3.67 ± 3.28;
2.0(2–4)
3.39 ± 0.85;
3.0(3–4)
3.64 ± 1.06;
4.0(3–4)
No. of CD %(n)
—
—
—
χ2 (3) = 0.293;
p = 0.961
χ2 (3) = 1.018;
p = 0.797
χ2 (3) = 12.408;
p = 0.006
χ2 (3) = 3.998;
p = 0.262
χ2 (2) = 0.193;
p = 0.979
χ2 (2) = 5.725;
p = 0.126
None
14.7(122)
14.2(47)
15(75)
9.98 ± 3.67;
9(7–12)
6.69 ± 2.94;
6.0(5–8)
5.34 ± 2.77;
5.0(3–7)
4.36 ± 3.32;
3.0(2–6)
3.15 ± 0.98;
3.0(3–4)
3.25 ± 1.13;
4.0(3–4)
One
52.2(434)
47.9(158)
55.1(276)
10.02 ± 3.52;
10(7–12.25)
6.88 ± 3.25;
7.0(4–9)
5.14 ± 2.48;
5.0(4–6)
4.18 ± 2.98;
3.0(2–6)
3.15 ± 1.01;
3.0(3–4)
3.54 ± 0.91;
4.0(3–4)
Two to three
31.5(262)
37(122)
27.9(140)
9.98 ± 3.82;
10.0(7–13)
6.76 ± 2.66;
7.0(5–8)
6.10 ± 2.86;
6.0(4–8)
4.44 ± 3.31;
3.0(2–7)
3.11 ± 1.16;
3.0(2–4)
3.63 ± 0.87;
4.0(3–4)
Four or more
1.6(13)
0.9(3)
2(10)
10.33 ± 1.53;
10.0(9–11)
8.00 ± 3.68;
7.0(4.75–12.25)
9.0 ± 1.73;
10.0(7–10)
6.30 ± 3.37;
6.0(3.5–9.5)
3.00 ± 1.0;
3.0(2–4)
3.0 ± 1.33;
4.0(1.75–4)
Type of CD %(n)
—
—
—
χ2 (2) = 1.476;
p = 0.478
χ2 (2) = 1.691;
p = 0.429
χ2 (2) = 1.659;
p = 0.436
χ2 (2) = 9.832;
p = 0.007
χ2 (2) = 0.063;
p = 0.969
χ2 (2) = 2.692;
p = 0.260
Int. J. Environ. Res. Public Health 2023, 20, 4937
5 of 12
Table 1. Cont.
Descriptive Statistics
Sleep Quality (Total)
Frailty (Total)
Quality of Life (Total)
Total
(n = 831)
Nursing Home
(n = 330)
Community
(n = 501)
Nursing Home
(n = 330)
M ± SD; Mdn(IQR)
Chronic malignant dis. (cancer)
13.2(110)
4.8(16)
18.8(94)
11.31 ± 4.44;
11.5(8.25–15.25)
6.78 ± 3.05;
7.0(4.75–8)
6.44 ± 2.87;
5.5(4–9)
3.81 ± 2.88;
3.0(2–5.25)
3.13 ± 1.09;
3.0(2–4)
3.63 ± 0.84;
4.0(3–4)
Non-malignant CD
65.2(542)
73.6
(243)
59.7(299)
9.92 ± 3.60;
10.0(7–13)
6.83 ± 3.12;
7.0(4–9)
5.51 ± 2.70;
5.0(4–7)
4.32 ± 3.15;
3.0(2–7)
3.14 ± 1.08;
3.0(2–4)
3.56 ± 0.92;
4.0(3–4)
Malignant and non-malignant CD
6.9(57)
7.3(24)
6.6(33)
10.0 ± 3.41;
10.0(7.25–11.75)
7.45 ± 2.77;
7.0(6–8)
5.88 ± 2.71;
6.0(3.25–8)
5.70 ± 3.08;
5.0(3–8)
3.08 ± 1.06;
3.0(2–4)
3.30 ± 1.02;
4.0(3–4)
—
—
—
—
—
—
7.01 ± 3.10;
7.0(5–9)
5.56 ± 2.83;
5.0(3–7)
4.55 ± 3.24;
4.0(2–6)
3.19 ± 1.08;
3.0(2–4)
3.46 ± 1.03;
4.0(3–4)
Variables
Experienced the following events in the past year?
Death of a loved
one
Community
(n = 501)
M ± SD; Mdn(IQR)
Nursing Home
(n = 330)
M ± SD; Mdn(IQR)
Community
(n = 501)
M ± SD; Mdn(IQR)
Y
22.5(187)
20.6(68)
23.8(119)
N
77.5(644)
79(262)
76.2(382)
10.11 ± 3.71;
10.0(7–13)
6.79 ± 3.04;
7.0(4–8)
5.56 ± 2.68:
5.0(4–7)
4.25 ± 3.11;
3.0(2–6)
3.12 ± 1.05;
3.0(2–4)
3.52 ± 0.92;
4.0(3–4)
U = 8039.0,
p = 0.214
U = 21,897.0,
p = 0.544
U = 8822.5,
p = 0.902
U = 21,442.5;
p = 0.347
U = 8501.5;
p = 0.549
U = 21,627.5;
p = 0.387
Y
18.5(154)
17(56)
19.6(98)
9.52 ± 3.55;
10.0(7.25–11.75)
8.48 ± 3.18;
8.0(7–10)
6.79 ± 2.93;
7.0(4.25–9)
5.84 ± 3.40;
6.0(3–9)
3.07 ± 1.14;
3.0(2–4)
3.02 ± 1.01;
3.0(2.75–4)
N
81.5(677)
83(274)
80.4(403)
10.10 ± 3.65;
10.0(7–13)
6.44 ± 2.89;
6.0(4–8)
5.31 ± 2.60;
5.0(4–7)
3.95 ± 2.96;
3.0(2–5)
3.15 ± 1.04;
3.0(2–4)
3.63 ± 0.90;
4.0(3–4)
U = 7026.5,
p = 0.319
U = 12,003.0,
p < 0.001
U = 5427.5;
p < 0.001
U = 13,423.0;
p < 0.001
U = 7420.0;
p = 0.687
U = 12,964.5;
p < 0.001
Severe disease (self)
—
Y
15.9(132)
16.1(53)
15.8(79)
10.60 ± 4.03;
10.0(7–13)
6.70 ± 2.70;
6.0(5–8)
5.89 ± 2.66;
6.0(4–8)
3.87 ± 2.78;
3.0(2–6)
2.92 ± 1.30;
3.0(2–4)
3.66 ± 0.70;
4.0(3–4)
N
84.1(699)
83.9(277)
84.2(422)
9.88 ± 3.55;
10.0(7–12)
6.86 ± 3.12;
7.0(5–9)
5.49 ± 2.72;
5.0(4–7)
4.41 ± 3.20;
3.0(2–7)
3.17 ± 1.0;
3.0(2–4)
3.48 ± 0.99;
4.0(3–4)
U = 6787.0,
p = 0.380
U = 16,325.5,
p = 0.770
U = 6690.0;
p = 0.303
U = 15,438.5;
p = 0.294
U = 6668.5;
p = 0.272
U = 15,312.5;
p = 0.214
—
Divorce or end of
intimate
relationship
Nursing Home
(n = 330)
M ± SD; Mdn(IQR)
9.56 ± 3.31;
9.0(8–12)
—
Severe disease
(loved one)
Community
(n = 501)
M ± SD; Mdn(IQR)
Y
5.8(48)
3.6(12)
7.2(36)
13.92 ± 4.50;
16.5(13–17)
6.36 ± 2.71;
6.0(4.25–9)
5.75 ± 1.82;
6.0(4–7)
4.58 ± 3.35;
3.0(2–7.75)
1.75 ± 1.14;
1.0(1–2)
3.58 ± 0.97;
4.0(3–4)
N
94.2(783)
96.4(318)
92.8(465)
9.85 ± 3.52;
10.0(7–12)
6.88 ± 3.08;
7.0(5–8)
5.55 ± 5.74;
5.0(4–7)
4.30 ± 3.13;
3.0(2–6)
3.19 ± 1.02;
3.0(2.75–4)
3.50 ± 0.95;
4.0(3–4)
U = 849.5,
p < 0.001
U = 7752.5,
p = 0.458
U = 1740.0;
p = 0.602
U = 8087.5;
p = 0.734
U = 684.5;
p < 0.001
U = 7870.5;
p = 0.518
U = 9355.5,
p < 0.001
U = 22,121.0,
p = 0.657
U = 10,133.0;
p = 0.071
U = 21,639.0;
p = 0.426
U = 6471.5;
p < 0.001
U = 17,769.0;
p < 0.001
—
Are you satisfied with your living environment?
Yes
77.5(611)
69.4(229)
76.2(382)
9.45 ± 3.41;
10.0(7–12)
6.75 ± 2.84;
7.0(5–8)
5.43 ± 2.90;
5.0(3–8)
4.26 ± 3.11;
3.0(2–6)
3.39 ± 0.97;
3.0(3–4)
3.61 ± 0.87;
4.0(3–4)
No
26.5(220)
30.6(101)
23.8(119)
11.26 ± 3.82;
11.0(9–14)
7.11 ± 3.67;
7.0(5–9)
5.84 ± 2.21;
6.0(4–7)
4.52 ± 3.23;
3.0(2–7)
2.54 ± 1.02;
2.0(2–3)
3.18 ± 1.13;
3.0(2–4)
10 ± 3.63;
10.0(7–12.25)
6.84 ± 3.06;
7.0(5–8.50)
5.56 ± 2.71;
5.0(4–7)
4.32 ± 3.14;
3.0(2–6)
3.13 ± 1.06;
3.0(2–4)
3.51 ± 0.95;
4.0(3–4)
Total
Mann-Whitney U test for total
U = 42,104.0; p < 0.001
U = 59,181; p < 0.001
U = 64,849.5; p < 0.001
Note: n—Sample size; %—Percent of participants; SD—Standard deviation; M—Mean; Mdn—Median; IQR—Interquartile range; DS—Descriptive statistics; HE—Higher Education;
dis.—disease; CD—Chronic disease; Y—Year.
Int. J. Environ. Res. Public Health 2023, 20, 4937
6 of 12
As shown in Table 1, sleep quality scores differed between participants in nursing
homes (M = 10; SD = 3.63) and in the community (M = 6.84; SD = 3.06, U = 42,104.0;
p < 0.001). Sleep quality scores also differed between men and women in community settings (U = 21,255. 5; p < 0.001), but not among nursing home residents. Data also indicate
a significant association between sleep quality and age among community-dwelling participants (rs = 0.227; p < 0.001). Sleep quality was also associated with relationship status
(χ2 (4)Nursing home = 27.123; pNursing home < 0.001; χ2 (4)Community = 75.123; pCommunity < 0.001).
The quality of sleep in community dwellers differs by chronic disease diagnosis (U = 12,003.0;
p < 0.001; M = 8.48, SD = 3.18). For participants in nursing homes, their sleep differs if they
did not have an intimate relationship (U = 849.5; p < 0.001; M = 13.92, SD = 4.50) and if they
were satisfied with the living environment or not (U = 9355.5; p < 0.001; M = 9.45, SD = 3.41).
Data indicate a significant difference in the prevalence of frailty between participants
in nursing homes (M = 5.56; SD = 2.71) and community settings (M = 4.32; SD = 3.14,
U = 59,181; p < 0.001). There is a difference in the mean scores related to gender between these two groups (MNursing home = 10.04; SDNursing home = 3.63; MCommunity = 4.59;
SDCommunity = 3.15), which remains statistically significant for both groups (UNursing home
= 8331.0; pNursing home < 0.001; UCommunity = 24,499.5; pCommunity = 0.005). There is also a
statistical correlation between frailty and age among nursing homes (rs = 0.310; p < 0.001)
and community dwellings participants (rs = 0.250; p < 0.001). The level of education and
the prevalence of frailty was statistically associated with participants from nursing homes
(χ2 (2) = 16.038; p = 0.003) and community residences (χ2 (2) = 18.059; p < 0.001). There is a
statistical association between the number of chronic non-communicable diseases and the
prevalence of frailty in the nursing home participants (χ2 (3) = 12.408; p = 0.006), but not
among community residents. However, there is a statistical association between the type of
chronic non-communicable disease and the prevalence of frailty in participants from the
community dwellings (χ2 (2) = 9.832; p = 0.007). In both groups, there is also a statistically
significant association between the diagnosis of severe chronic disease and the prevalence of frailty (χ2 (4)Nursing home = 27.123; pNursing home < 0.001; χ2 (4)Community = 75.123;
pCommunity < 0.001).
Quality of life differed significantly (U = 64,849.5; p < 0.001) between participants
from nursing homes (M = 3.13; SD = 1.06) and those from community dwellings (M = 3.51;
SD = 0.95). Quality of life is higher among men than women among nursing home participants (U = 9659.0; p = 0.020). In addition, there is also a difference in quality of life in
both groups regarding relationship status (χ2 (4)Nursing home = 11.606; pNursing home = 0.021;
χ2 (4)Community = 25.534; pCommunity < 0.001). There is also a difference in quality of
life regarding education for both groups (χ2 (2)Nursing home = 6.512; pNursing home = 0.039;
χ2 (2)Community = 15.534; pCommunity < 0.001). In addition, quality of life is lower among
community-dwelling older adults with one or more chronic disease (U = 12,964.5; p < 0.001;
M = 3.02, SD = 1.01). Among participants from nursing homes, there is a difference
in the quality of life if they had experienced a divorce or breakup of an intimate relationship (U = 684.5; p < 0.001; M = 1.75, SD = 1.14). Groups differed in quality of life
regarding satisfaction/dissatisfaction with their living environment (UNursing home = 6471.5;
pNursing home < 0.001; UCommunity = 17,769.0; pCommunity < 0.001).
Table 2 shows the Spearman correlations among participants’ reported sleep quality,
frailty, and quality of life. Correlations for participants from nursing homes range from
0.647 to 0.418, and for community-dwelling participants, range from 0.533 to 0.467.
Int. J. Environ. Res. Public Health 2023, 20, 4937
7 of 12
Table 2. Spearman correlations matrix of sleep quality, frailty, and quality of life between groups.
Correlations Matrix
Nursing home
Community
Sleep quality
(Total)
Frailty (Total)
Quality of life
(Total)
Sleep quality
(Total)
1
0.418 **
−0.647 **
Frailty (Total)
0.418 **
1
−0.435 **
Quality of life
(Total)
−0.647 **
−0.435 **
1
Sleep quality
(Total)
Frailty (Total)
Quality of life
(Total)
Sleep quality
(Total)
1
0.467 **
−0.533 **
Frailty (Total)
0.467 **
1
−0.524 **
Quality of life
(Total)
−0.533 **
−0.524 **
1
Note: **—Correlation is significant at the 0.01 level (2-tailed).
Spearman’s correlation (Table 2) was used to determine associations between the two
participant groups’ sleep quality, frailty, and quality of life scores. There was a strong
positive correlation between poor sleep quality and frailty in participants from nursing
homes (rs = 0.418, n = 330, p < 0.001) and a strong positive correlation in participants
from the community-dwelling group (rs = 0.467, n = 501, p < 0.001). Both groups had
a strong negative correlation between frailty and quality of life (rs Nursing home = −0.435,
nNursing home = 330, pNursing home < 0.001; rs Community = −0.524, nCommunity = 501, pCommunity
< 0.001). Both participant groups also had a strong negative correlation between sleep
quality and quality of life (rs Nursing home = −0.647, nNursing home = 330, pNursing home < 0.001;
rs Community = −0.533, nCommunity = 501, pCommunity < 0.001).
We also looked at whether prediction variables (gender, chronic disease, income, social
interaction, support (formal or informal), physical activity, experience in the past year: with
the death of a loved one) predict sleep quality, frailty, and quality of life in a nursing home
and community-dwelling participants. Overall, regression models for nursing home and
community-dwelling participants were statistically significant. Results for sleep quality
showed that the predictor variables explained 28.4% of the variance among nursing home
participants (F(10,490) = 18.223, p < 0.001) and 23.3% of the variance for communitydwelling participants (F(10,490) = 21.340, p < 0.001). Models explained 18.6% of the variance
for frailty among participants in the nursing homes (F(10,319) = 10.481, p < 0.001) and 45.0%
for community-dwelling participants (F(10,490) = 57.539, p < 0.001). Predictors explain
22.4% of the variance in quality of life for participants in nursing homes (F(10,319) = 13.279,
p < 0.001) and 34.3% for community-dwelling participants (F(10,490) = 36.776, p < 0.001).
In turn, sleep quality and frailty explain 42.3% of the variance in quality of life among
older adults in nursing homes (F(2327) = 119.712, p < 0.001) and 34.8% for communitydwelling older adults (F(2498) = 132.933, p < 0.001).
4. Discussion
Our findings indicate that poor sleep quality and frailty are associated with the quality
of life among older adults living in community and nursing home settings. This study
allows direct comparisons between community-dwelling older adults or residents from
nursing homes for all studied variables. Some previous studies indicated that poor sleep
quality is significantly related to the frailty of community-dwelling older adults [4,31,32]
and older adults in aged care homes [9] and in middle-aged populations [33,34]. In a
systematic review of seven studies, Wai and Yu [35] noted evidence for an association
Int. J. Environ. Res. Public Health 2023, 20, 4937
8 of 12
between perceived sleep quality and frailty among older adults. Similarly, in their metaanalysis, Pourmotabbed, et al. [35] noted that longer and shorter sleep durations are
associated with an increased risk of frailty.
Eighty-five percent of older adults (community-dwelling and nursing home) have
one or more chronic diseases. Comorbidity (two or more chronic conditions) is present in
38% of community-dwelling older adults and 31% of older adults in nursing homes and
is also important for understanding sleep quality. These results are encouraging because
Sheikh, et al. [36] noted that chronic disease is prevalent globally and that more than half
of older adults experience comorbidity.
At the same time, 69–76% (69% community-dwelling older adults and 76% older
adults in nursing homes) are satisfied with their living environment. These results are
important because satisfaction with the living environment is related to quality of life,
social satisfaction, and, indirectly, loneliness [37,38]. We also found differences in the
quality-of-life score between those who are satisfied or not with their living environment in
the community-dwelling older adults and older adults in nursing homes.
Our study found that frailty prevalence was 36.5% among community-dwelling older
adults and 58.5% for older adults in nursing homes in our sample, partially comparable
with previous results in other countries only for community-dwelling older adults. In
China, the most frailty among older adults with chronic diseases in rural areas was 21% [31].
Hladek et al. [39] found that 49% of community-dwelling people with at least one chronic
disease in the United States were frail/prefrail.
Determining poor sleep quality by a cut-off global PSQI score ≥ five found that 76.0%
of community-dwelling older adults reported poor sleep quality, and 95.8% of older adults
from nursing homes reported poor sleep quality. A study from Malaysia reported that
approximately 95% of participants from nursing homes reported poor sleep quality [9].
The analysis found that older adults’ relationship status, physical activity, social
interaction, support, chronic disease, and income affect the sleep quality, frailty, and quality
of life of community-dwelling older adults and residents in nursing homes. With these
factors, we can explain 28.4% of the variance of sleep quality for older adults in nursing
homes and 23.3% for community-dwelling older adults. With studied factors, we can
explain 18.9% of the total variance of the frailty of older adults in nursing homes and
45% for community-dwelling older adults. We can also explain 22.4% of the variance for
the quality of life for older adults in nursing homes and 34.3% for community-dwelling
older adults. According to our findings for older adults, regardless of whether they live
in the community or nursing home, for better sleep quality, prevention of frailness, and
higher quality of life, it the most important that they are physically active and have social
interaction. In a systematic review, Oliveira, et al. [40] noted that the meta-analysis results
showed that physical activity prevents frailty. Wang, Wang, Xie, Liu, and Wang [5] indicated
that moderate physical activity is more effective than intensive activity for better sleep
quality for older and young populations. Souza, Oliveras-Fabregas, Minobes-Molina, de
Camargo Cancela, Galbany-Estragués, and Jerez-Roig [11] noted that included studies
indicated positive results connecting physical activity and quality of life of older adults.
Moderate evidence suggests that physical activity improves individuals’ quality of life and
well-being in all ages [41]. Furthermore, Gothe et al. [42] noted that physical activity and
sleep quality were significantly correlated and that sleep quality indirectly influences the
quality of life. Tighe et al. [43] pointed out that social contacts, or lack of them, are also
important for sleep quality, particularly for older adults, which is in line with our results
because older adults are more often prone to loneliness due to life events.
We found that the predicted sleep quality and frailty variables explain 42.3% of
the quality-of-life variance for older adults in nursing homes and 34.8% for communitydwelling older adults. According to the findings, monitoring the prevalence of comorbidity
and frailty is important for the healthcare system and the factors affected by them. Nevertheless, we must be aware that both comorbidity and frailty are related to disability and
dependency in late life worldwide. Moreover, some other studies support our results, for
Int. J. Environ. Res. Public Health 2023, 20, 4937
9 of 12
example, that frailty [44–46] and poor sleep quality [19,47,48] are related to the quality of
life among older adults, even though they are all carried out in the community. Our results
show that health-related aspects of quality of life among older adults are related to sleep
impairment and confirm that perceived good sleep quality predicts the quality of life of
older adults, even if they have no sleep impairment.
The strengths of this study lie in the data complexity and comprehensiveness of data
analysis on the association between sleep quality and the incidence of frailty and the resulting impact on the quality of life of older people in nursing homes and community-dwelling.
The results are also supported by the fact that no significant differences were detected
between the group of older people in the home and the community. The study provides
detailed, reliable, and representative cross-sectional findings on differences in sleep quality,
frailty, and quality of life between older people in nursing homes and community-dwelling.
The extensive survey was subject to rigorous quality control, making it a high-quality data
source. Our results show differences in sleep quality, the prevalence of frailty, and the
quality of life in older people in nursing homes and the community, which can inform
future potential intervention targets.
This study had some limitations that need to be addressed; namely, it used a crosssectional design, so causal inferences cannot be made. Few studies have been published
comparing sleep quality and frailty and their associations with quality of life in older people in nursing homes and the community. Most studies have investigated the connection
between each component separately rather than its entirety with all three components.
Second, recall bias can occur in a cross-sectional study. Another study limitation could
present the type of sampling and its effect on the results. Due to the majority share of one
gender and location, we cannot generalize the results to the whole population. In addition,
the study used self-assessed data, which could introduce social desirability bias, where
respondents over- or under-report their answers based on social norms. The response rate
in the study could also be a limitation, as it was 41.5%, which could be considered satisfactory, and no major system failures were found. However, as participation in the study
was voluntary, we do not know whether the sample fully represents the key population
characteristics. Finally, we could not adjust for all potentially confounding factors nor any
potential interaction between sleep quality and paresis (weakness).
5. Conclusions
This cross-sectional study is the first to report data on associations between sleep
quality, frailty, and quality of life in Slovenians aged 65 and older living in community and
nursing homes. We found associations between poorer sleep quality and frailty and poorer
quality of life in community-dwelling older people and nursing home residents. A better
understanding of how sleep quality is affected by social, environmental, and biological
factors may lead to more effective ways to prevent the onset of frailty and its resulting
negative impact on the quality of life among older adults. The results of this research can
help healthcare professionals formulate strategies to enhance sleep quality among older
persons, particularly in nursing home settings where sleep quality is considerably poorer
and frailty more prevalent.
Author Contributions: Conceptualization, M.L., S.K., A.D., N.M.R., Z.F. and B.K.; data curation,
M.L., S.K. and Z.F.; formal analysis, M.L., S.K., A.D. and Z.F.; funding acquisition, M.L. and A.D.;
investigation, S.K., A.D., N.M.R., Z.F. and B.K.; methodology, M.L., S.K., N.M.R. and Z.F.; project
administration, M.L. and A.D.; resources, M.L.; software, S.K.; supervision, M.L. and A.D.; validation,
M.L., S.K., N.M.R. and Z.F.; visualization, M.L., S.K., A.D., N.M.R., Z.F. and B.K.; writing–original
draft, M.L., S.K., A.D., N.M.R., Z.F. and B.K.; writing–review & editing, M.L., S.K., A.D., N.M.R., Z.F.
and B.K. All authors have read and agreed to the published version of the manuscript.
Funding: A study reported in this publication was supported by the Slovenian Research Agency
(BI-US/18-20-009) and the National Cancer Institute of the National Institutes of Health under Award
Number R01CA194178. The content is solely the responsibility of the authors and does not necessarily
represent the official views of the National Institutes of Health.
Int. J. Environ. Res. Public Health 2023, 20, 4937
10 of 12
Institutional Review Board Statement: The study was conducted according to the guidelines of the
Declaration of Helsinki and approved by the Ethics Committee of the University of Maribor, Faculty
of Health Sciences (Ref.: 038/2018/2510-1/504 and 15 March 2018).
Informed Consent Statement: Informed consent was obtained from all subjects involved in the
study. The patient(s) has obtained written informed consent to publish this paper.
Data Availability Statement: Additional data from this study are not publicly available to maintain
participants’ anonymity but can be provided on request.
Acknowledgments: The authors would like to thank all participants for participating in the study
research and the nurses who have helped with the recruitment. Furthermore, we also want to thank
the nursing home for allowing us to conduct the study.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Ofori-Asenso, R.; Chin, K.L.; Mazidi, M.; Zomer, E.; Ilomaki, J.; Zullo, A.R.; Gasevic, D.; Ademi, Z.; Korhonen, M.J.; LoGiudice,
D.; et al. Global Incidence of Frailty and Prefrailty Among Community-Dwelling Older Adults: A Systematic Review and
Meta-analysis. JAMA Netw. Open 2019, 2, e198398. [CrossRef] [PubMed]
Clegg, A.; Young, J.; Iliffe, S.; Rikkert, M.O.; Rockwood, K. Frailty in elderly people. Lancet 2013, 381, 752–762. [CrossRef]
[PubMed]
Collard, R.M.; Boter, H.; Schoevers, R.A.; Oude Voshaar, R.C. Prevalence of Frailty in Community-Dwelling Older Persons: A
Systematic Review. J. Am. Geriatr. Soc. 2012, 60, 1487–1492. [CrossRef] [PubMed]
Sun, X.-H.; Ma, T.; Yao, S.; Chen, Z.-K.; Xu, W.-D.; Jiang, X.-Y.; Wang, X.-F. Associations of sleep quality and sleep duration with
frailty and pre-frailty in an elderly population Rugao longevity and ageing study. BMC Geriatr. 2020, 20, 9. [CrossRef]
Wang, H.; Wang, J.; Xie, B.; Liu, B.; Wang, J. Multi-dimensional frailty and its risk factors among older residents in long-term care
facilities in Shanghai, China. Int. J. Nurs. Sci. 2021, 8, 298–303. [CrossRef]
World Health Organization. Ageing and Health. Available online: https://www.who.int/news-room/fact-sheets/detail/ageingand-health (accessed on 26 October 2022).
Alqahtani, B.A. Association between Physical Frailty and Sleep Quality among Saudi Older Adults: A Community-Based,
Cross-Sectional Study. Int. J. Environ. Res. Public Health 2021, 18, 12741. [CrossRef]
Azri, M.A.; Dahlan, A.; Masuri, M.G.; Isa, K.A.M. Sleep Quality among Older Persons in Institutions. Procedia Soc. Behav. Sci.
2016, 234, 74–82. [CrossRef]
Kumar, S.; Wong, P.S.; Hasan, S.S.; Kairuz, T. The relationship between sleep quality, inappropriate medication use and frailty
among older adults in aged care homes in Malaysia. PLoS ONE 2019, 14, e0224122. [CrossRef]
Suzuki, K.; Miyamoto, M.; Hirata, K. Sleep disorders in the elderly: Diagnosis and management. J. Gen. Fam. Med. 2017, 18, 61–71.
[CrossRef]
Souza, D.L.B.; Oliveras-Fabregas, A.; Minobes-Molina, E.; de Camargo Cancela, M.; Galbany-Estragués, P.; Jerez-Roig, J. Trends of
multimorbidity in 15 European countries: A population-based study in community-dwelling adults aged 50 and over. BMC
Public Health 2021, 21, 76. [CrossRef]
Ward, B.W.; Schiller, J.S. Prevalence of multiple chronic conditions among US adults: Estimates from the National Health Interview
Survey, 2010. Prev. Chronic Dis. 2013, 10, E65. [CrossRef]
The National Institute on Aging. Today’s Research on Aging: Program and Policy Implications; Population Reference Bureau:
Washington, DC, USA, 2018.
Kim, M.; Um, Y.-H.; Kim, T.-W.; Kim, S.-M.; Seo, H.-J.; Jeong, J.-H.; Lee, J.; Kim, S.; Cho, I.H.; Kim, S.-Y.; et al. Association Between
Age and Sleep Quality: Findings From a Community Health Survey. Sleep Med. Res. 2021, 12, 155–160. [CrossRef]
Cavuoto, M.G.; Ong, B.; Pike, K.E.; Nicholas, C.L.; Bei, B.; Kinsella, G.J. Objective but not subjective sleep predicts memory in
community-dwelling older adults. J. Sleep Res. 2016, 25, 475–485. [CrossRef]
Hughes, J.M.; Song, Y.; Fung, C.H.; Dzierzewski, J.M.; Mitchell, M.N.; Jouldjian, S.; Josephson, K.R.; Alessi, C.A.; Martin, J.L.
Measuring Sleep in Vulnerable Older Adults: A Comparison of Subjective and Objective Sleep Measures. Clin. Gerontol. 2018, 41,
145–157. [CrossRef]
Yaremchuk, K. Sleep disorders in the elderly. Clin. Geriatr. Med. 2018, 34, 205–216. [CrossRef]
Gooneratne, N.S.; Vitiello, M.V. Sleep in older adults: Normative changes, sleep disorders, and treatment options. Clin. Geriatr.
Med. 2014, 30, 591–627. [CrossRef]
Basnet, S.; Merikanto, I.; Lahti, T.; Männistö, S.; Laatikainen, T.; Vartiainen, E.; Partonen, T. Associations of common chronic
non-communicable diseases and medical conditions with sleep-related problems in a population-based health examination study.
Sleep Sci. 2016, 9, 249–254. [CrossRef]
Seo, J.; Choi, B.; Kim, S.; Lee, H.; Oh, D. The relationship between multiple chronic diseases and depressive symptoms among
middle-aged and elderly populations: Results of a 2009 korean community health survey of 156,747 participants. BMC Public
Health 2017, 17, 844. [CrossRef]
Int. J. Environ. Res. Public Health 2023, 20, 4937
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
11 of 12
Andersen, R.M. National health surveys and the behavioral model of health services use. Med. Care 2008, 46, 647–653. [CrossRef]
White, S.M.; Wójcicki, T.R.; McAuley, E. Physical activity and quality of life in community dwelling older adults. Health Qual. Life
Outcomes 2009, 7, 10. [CrossRef]
Von Elm, E.; Altman, D.G.; Egger, M.; Pocock, S.J.; Gøtzsche, P.C.; Vandenbroucke, J.P. The Strengthening the Reporting of
Observational Studies in Epidemiology (STROBE) statement: Guidelines for reporting observational studies. J. Clin. Epidemiol.
2008, 61, 344–349. [CrossRef] [PubMed]
Buysse, D.J.; Reynolds, C.F., 3rd; Monk, T.H.; Berman, S.R.; Kupfer, D.J. The Pittsburgh Sleep Quality Index: A new instrument
for psychiatric practice and research. Psychiatry Res. 1989, 28, 193–213. [CrossRef] [PubMed]
Gobbens, R.J.; van Assen, M.A.; Luijkx, K.G.; Wijnen-Sponselee, M.T.; Schols, J.M. The Tilburg Frailty Indicator: Psychometric
properties. J. Am. Med. Dir. Assoc. 2010, 11, 344–355. [CrossRef] [PubMed]
Vetrano, D.L.; Palmer, K.; Marengoni, A.; Marzetti, E.; Lattanzio, F.; Roller-Wirnsberger, R.; Lopez Samaniego, L.; RodríguezMañas, L.; Bernabei, R.; Onder, G. Frailty and Multimorbidity: A Systematic Review and Meta-analysis. J. Gerontol. A Biol. Sci.
Med. Sci. 2019, 74, 659–666. [CrossRef] [PubMed]
Stats Tutor Spearman’s Correlation. Available online: https://www.statstutor.ac.uk/ (accessed on 26 October 2022).
Polit, D.F.; Beck, C.T. Nursing Research: Generating and Assessing Evidence for Nursing Practice, 11th ed.; Wolters Kluwer Health,
Lippincott Williams and Wilkins: Philadelphia, PA, USA, 2021.
World Medical Association; World Medical Association Declaration of Helsinki. Ethical principles for medical research involving
human subjects. Bull. World Health Organ. 2001, 79, 373–374.
Council of Europe. Convention for the Protection of Human Rights and Dignity of the Human Being with Regard to the
Application of Biology and Medicine: Convention on Human Rights and Biomedicine: European Treaty Series No. 164—Oviedo,
4.4. 1997. In Die Bedeutung der Philosophie für Die Rechtswissenschaft: Dargestellt Am Beispiel der Menschenrechtskonvention zur
Biomedizin; Council of Europe: Brussels, Belgium, 2001; pp. 67–80.
Fu, P.; Zhou, C.; Meng, Q. Associations of Sleep Quality and Frailty among the Older Adults with Chronic Disease in China:
The Mediation Effect of Psychological Distress. Int. J. Environ. Res. Public Health 2020, 17, 5240. [CrossRef]
Liu, X.; Wang, C.; Qiao, X.; Si, H.; Jin, Y. Sleep quality, depression and frailty among Chinese community-dwelling older adults.
Geriatr. Nurs. 2021, 42, 714–720. [CrossRef]
Shih, A.C.; Chen, L.H.; Tsai, C.C.; Chen, J.Y. Correlation between Sleep Quality and Frailty Status among Middle-Aged and Older
Taiwanese People: A Community-Based, Cross-Sectional Study. Int. J. Environ. Res. Public Health 2020, 17, 9457. [CrossRef]
Kaur, S.; Banerjee, N.; Miranda, M.; Slugh, M.; Sun-Suslow, N.; McInerney, K.F.; Sun, X.; Ramos, A.R.; Rundek, T.; Sacco, R.L.;
et al. Sleep quality mediates the relationship between frailty and cognitive dysfunction in non-demented middle aged to older
adults. Int. Psychogeriatr. 2019, 31, 779–788. [CrossRef]
Wai, J.L.; Yu, D.S. The relationship between sleep-wake disturbances and frailty among older adults: A systematic review. J. Adv.
Nurs. 2020, 76, 96–108. [CrossRef]
Sheikh, S.A.; Donaldson, L.; Dhingra-Kumar, N.; Bates, D.; Kelley, E.; Larizgoitia, I.; Panesar, S.; Singh, C.; de Silva, D.;
Mercer, S.; et al. Multimorbidity: Technical Series on Safer Primary Care; World Health Organization: Geneva, Switzerland, 2016.
Hur, M.; Morrow-Jones, H. Factors That Influence Residents’ Satisfaction With Neighborhoods. Environ. Behav. 2008, 40, 619–635.
[CrossRef]
Kemperman, A.; van den Berg, P.; Weijs-Perrée, M.; Uijtdewillegen, K. Loneliness of Older Adults: Social Network and the Living
Environment. Int. J. Environ. Res. Public Health 2019, 16, 406. [CrossRef]
Hladek, M.D.; Gill, J.; Bandeen-Roche, K.; Walston, J.; Allen, J.; Hinkle, J.L.; Lorig, K.; Szanton, S.L. High coping self-efficacy
associated with lower odds of pre-frailty/frailty in older adults with chronic disease. Aging Ment. Health 2020, 24, 1956–1962.
[CrossRef]
Oliveira, J.S.; Pinheiro, M.B.; Fairhall, N.; Walsh, S.; Chesterfield Franks, T.; Kwok, W.; Bauman, A.; Sherrington, C. Evidence on
Physical Activity and the Prevention of Frailty and Sarcopenia Among Older People: A Systematic Review to Inform the World
Health Organization Physical Activity Guidelines. J. Phys. Act. Health 2020, 17, 1247–1258. [CrossRef]
Marquez, D.X.; Aguiñaga, S.; Vásquez, P.M.; Conroy, D.E.; Erickson, K.I.; Hillman, C.; Stillman, C.M.; Ballard, R.M.; Sheppard,
B.B.; Petruzzello, S.J.; et al. A systematic review of physical activity and quality of life and well-being. Transl. Behav. Med. 2020,
10, 1098–1109. [CrossRef]
Gothe, N.P.; Ehlers, D.K.; Salerno, E.A.; Fanning, J.; Kramer, A.F.; McAuley, E. Physical Activity, Sleep and Quality of Life in Older
Adults: Influence of Physical, Mental and Social Well-being. Behav. Sleep Med. 2020, 18, 797–808. [CrossRef]
Tighe, C.A.; Dautovich, N.D.; McCrae, C.S. Daily Social Contact in Relation to Sleep: The Role of Age. Behav. Sleep Med. 2016, 14,
311–324. [CrossRef]
Gobbens, R.J.; Uchmanowicz, I. Assessing Frailty with the Tilburg Frailty Indicator (TFI): A Review of Reliability and Validity.
Clin. Interv. Aging 2021, 16, 863–875. [CrossRef]
Kojima, G.; Iliffe, S.; Jivraj, S.; Walters, K. Association between frailty and quality of life among community-dwelling older people:
A systematic review and meta-analysis. J. Epidemiol. Community Health 2016, 70, 716–721. [CrossRef]
Vanleerberghe, P.; De Witte, N.; Claes, C.; Verté, D. The association between frailty and quality of life when aging in place. Arch.
Gerontol. Geriatr. 2019, 85, 103915. [CrossRef]
Int. J. Environ. Res. Public Health 2023, 20, 4937
47.
48.
12 of 12
Tel, H. Sleep quality and quality of life among the elderly people. Neurol. Psychiatry Brain Res. 2013, 19, 48–52. [CrossRef]
Sella, E.; Cellini, N.; Borella, E. How Elderly People’s Quality of Life Relates to Their Sleep Quality and Sleep-Related Beliefs.
Behav. Sleep Med. 2021, 20, 112–124. [CrossRef] [PubMed]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual
author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to
people or property resulting from any ideas, methods, instructions or products referred to in the content.