The Relationship Between Social Isolation and Cognitive Frailty Among Community-Dwelling Older Adults: The Mediating Role of Depressive Symptoms

Figures & data

Table 1 Description and Univariate Analysis of Cognitive Frailty Among Community-Dwelling Older Adults (N = 496)

Variable	Total	Non-Cognitive Frailty	Cognitive Frailty	χ^2/t	p-value
Gender				3.389	0.066
Male	237(47.8)	201(49.8)	36(39.1)
Female	259(52.2)	203(50.2)	56(60.9)
Age (years)				8.725	0.013
60~69	267(53.8)	225(55.7)	42(45.7)
70~79	174(35.1)	142(35.1)	32(34.8)
≥80	55(11.1)	37(9.2)	18(19.6)
Educational level				22.217	<0.001
Primary school or below	110(22.2)	78(19.3)	32(34.8)
Junior high school	138(27.8)	105(26.0)	33(35.9)
Senior high school/Vocational senior school	127(25.6)	109(27.0)	18(19.6)
College or above	121(24.4)	112(27.7)	9(9.8)
Average monthly income (RMB)				13.679	<0.001
< 3000	186(37.5)	136(33.7)	50(54.3)
≥ 3000	310(62.5)	268(66.3)	42(45.7)
Marital status				0.070	0.792
Married	383(77.2)	311(77.0)	72(78.3)
Single	113(22.8)	93(23.0)	20(21.7)
BMI (kg/m^2)				0.124	0.725
18.5~23.9	213(42.9)	175(43.3)	38(41.3)
< 18.5 or > 23.9	283(57.1)	229(56.7)	54(58.7)
Number of chronic diseases				9.956	0.007
0 kind	203(40.9)	177(43.8)	26(28.3)
1 kind	178(35.9)	143(35.4)	35(38.0)
2 kinds	115(23.2)	84(20.8)	31(33.7)
Sleep disorder				38.542	<0.001
No	303(61.1)	273(67.6)	30(32.6)
Yes	193(38.9)	131(32.4)	62(67.4)
Social isolation				23.665	<0.001
No	373(75.2)	322(79.7)	51(55.4)
Yes	123(24.8)	82(20.3)	41(44.6)
GDS-15	2.31±2.25	2.00±1.99	3.74±3.06	−6.528	<0.001
FRAIL	0.68±0.72	0.48±0.69	1.55±0.72	−12.083	<0.001
MoCA	24.25±3.42	24.88±3.24	21.52±2.82	9.176	<0.001

Notes: Variables were presented as n (%) or mean±SD.

Abbreviations: BMI, body mass index; GDS-15, Geriatric Depression Scale 15-item; MoCA, Montreal Cognitive Assessment.

Table 2 Linear Regression Analysis of the Relationship Between Social Isolation and Depressive Symptoms

Variable	β	SE	t	p-value	VIF value
Social isolation (Reference = No)
Yes	0.873	0.248	3.524	<0.001	1.107
Gender (Reference = Male)
Female	−0.014	0.220	−0.003	0.950	1.172
Age (Reference = 60~69)
70~79	0.035	0.228	0.154	0.877	1.146
≥80	0.619	0.349	1.775	0.076	1.159
Educational level (Reference = Primary school or below)
Junior high school	−0.545	0.326	−1.671	0.095	1.764
Senior high school/Vocational senior school	−0.606	0.301	−2.011	0.045	1.956
College or above	−0.762	0.350	−2.178	0.030	2.183
Average monthly income (Reference = < 3000)
≥ 3000	−0.721	0.250	−2.886	0.004	1.414
Marital status (Reference = Married)
Single	−0.949	0.251	−3.779	<0.001	1.074
BMI (Reference = 18.5~23.9)
< 18.5 or > 23.9	−0.309	0.215	−1.483	0.139	1.033
Number of chronic diseases (Reference = 0 kind)
1 kind	−0.057	0.239	−0.239	0.812	1.279
≥2 kinds	−0.093	0.275	−0.339	0.735	1.289
Sleep disorder (Reference = No)
Yes	0.550	0.247	2.508	0.012	1.108

Abbreviations: BMI, body mass index; VIF, variance inflation factor.

Table 3 Logistic Regression Analysis of the Relationship Between Social Isolation, Depressive Symptoms and Cognitive Frailty

	Model 1			Model 2
	OR	95% CI	p-value	OR	95% CI	p-value
Social isolation (Reference = No)
Yes	2.132	1.253~3.628	0.005	1.769	1.018~3.075	0.040
Depressive symptoms				1.227	1.108~1.357	<0.001
Gender (Reference = Male)
Female	1.088	0.627~1.887	0.764	1.065	0.606~1.873	0.826
Age (Reference = 60~69)
70~79	1.032	0.580~1.835	0.916	1.065	0.591~1.918	0.835
≥80	2.490	1.154~5.371	0.020	2.273	1.033~5.000	0.041
Educational level (Reference = Primary school or below)
Junior high school	0.911	0.473~1.753	0.779	1.072	0.543~2.117	0.840
Senior high school/Vocational senior school	0.727	0.338~1.564	0.414	0.879	0.401~1.932	0.747
College or above	0.325	0.125~0.845	0.021	0.375	0.140~1.010	0.048
Average monthly income (Reference = < 3000)
≥3000	0.483	0.267~0.876	0.017	0.526	0.285~0.972	0.040
Marital status (Reference = Married)
Single	0.947	0.509~1.762	0.863	1.203	0.630~2.296	0.575
BMI (Reference = 18.5~23.9)
< 18.5 or > 23.9	1.184	0.708~1.979	0.519	1.317	0.774~2.241	0.309
Number of chronic diseases (Reference = 0 kind)
1 kind	1.956	1.048~3.649	0.035	2.043	1.075~3.884	0.029
≥2 kinds	2.072	1.074~3.996	0.030	2.246	1.138~4.434	0.020
Sleep disorder (Reference = No)
Yes	3.660	2.155~6.216	<0.001	3.554	2.063~6.124	<0.001

Abbreviation: BMI, body mass index.

Table 4 Bootstrap Analysis of the Mediating Effects of Depressive Symptoms

Path	Coefficient	Boot SE	Bootstrap 95% CI		Relative Proportion(%)
			LLCI	ULCI
Total effect	0.114	0.045	0.025	0.201
Direct effect	0.087	0.044	0.004	0.172	76.4
Indirect effect	0.027	0.012	0.003	0.051	23.6

Notes: Adjusted for gender, age, educational level, average monthly income, marital status, BMI, number of chronic diseases, and sleep disorder.

Abbreviations: Boot SE, Bootstrap standard error; LLCI, lower-level confidence interval; ULCI, upper-level confidence interval.

Figure 1 Mediating effects of depressive symptoms on the relationship between social isolation and cognitive frailty. *p < 0.05.

Data Sharing Statement

The data supporting this study’s findings are available on request from the corresponding author.