Associations of self-reported and objectively measured sleep disturbances with depression among primary caregivers of children with disabilities

Figures & data

Table 1 Sociodemographic characteristics of 175 female caregivers of children with disabilities, by depression status

	Total (n=175)	Depressed women (n=46)	Nondepressed women (n=129)	P-valuea
Age (years), mean (SD)	40.6 (8.7)	40.6 (7.9)	40.6 (8.9)	0.989
Hispanic, n (%)	82 (46.9)	21 (45.7)	61 (47.3)	0.849
Marital status, n (%)
Married or living with a partner	116 (66.3)	23 (50.0)	93 (72.1)	0.007
Divorced/separated/widowed/never married	59 (33.7)	23 (50.0)	36 (27.9)
BMI (kg/m^2), mean (SD)	29.6 (5.6)	31.0 (6.3)	29.0 (5.3)	0.037
Current smoker, n (%)	82 (46.9)	29 (63.0)	53 (41.1)	0.010
Alcohol consumption, n (%)	30 (17.1)	5 (10.9)	25 (19.4)	0.189
Unemployed/student, n (%)	79 (45.1)	22 (47.8)	57 (44.2)	0.670
Education level, n (%)
<High school	60 (34.3)	23 (50.0)	37 (28.7)	0.013
High school	59 (33.7)	15 (32.6)	44 (34.1)
>High school	56 (32.0)	8 (17.4)	48 (37.2)
Child disability group, n (%)
Mental and behavioral disorders	75 (42.9)	17 (37.0)	58 (45.0)	0.713
Diseases of musculoskeletal system and connective/skin tissue	32 (18.3)	8 (17.4)	24 (18.6)
Diseases of the nervous system	47 (26.9)	14 (30.4)	33 (25.6)
Congenital malformations and chromosomal abnormalities	21 (12.0)	7 (15.2)	14 (10.9)

Notes: Depression was defined using the PHQ-8 score ≥10.

a Student’s t-test was conducted for age and BMI; chi-square test was conducted for other sociodemographic characteristics (categorical variables). P-values less than 0.05 are shown in bold.

Abbreviations: BMI, body mass index; PHQ-8, eight-item Patient Health Questionnaire.

Table 2 Differences in subjective and objective-measured sleep parameters between depressed and non-depressed women

Dependent variables	Depressed (n=46)	Nondepressed (n=129)	P-valuea	Univariate models		Multivariable modelsb
				β (SE)	P-value	β (SE)	P-value
Subjective: PSQI-reported sleep parameters
Total time in bed (hours), mean (SD)	6.6 (1.5)	7.3 (1.6)	0.014	−0.67 (0.27)	0.014	−0.61 (0.29)	0.033
Sleep latency (minutes), median (interquartile)c	60.0 (30.0, 90.0)	20.0 (10.0, 60.0)	<0.001	0.72 (0.19)	<0.001	0.58 (0.20)	0.003
Sleep duration (hours), mean (SD)	5.8 (1.3)	6.6 (1.4)	0.001	−0.81 (0.24)	0.001	−0.71 (0.25)	0.006
Sleep efficiency (%), median (interquartile)c	88.2 (77.4, 100.0)	91.7 (80.0, 100.0)	0.570	−0.02 (0.03)	0.540	−0.01 (0.03)	0.743
Global PSQI score, median (interquartile)c	11.0 (9.0, 13.0)	6.0 (4.0, 9.0)	<0.001	0.56 (0.08)	<0.001	0.53 (0.08)	<0.001
Objective: actigraphy-measured sleep parametersd
Total time in bed (hours), mean (SD)	7.7 (1.3)	8.1 (1.3)	0.076	−0.40 (0.22)	0.076	−0.32 (0.23)	0.174
Sleep latency (minutes), median (interquartile)c	7.2 (2.9, 17.1)	11.1 (4.7, 18.9)	0.453	−0.15 (0.23)	0.513	−0.19 (0.23)	0.408
Sleep duration (hours), mean (SD)	6.4 (0.9)	6.9 (1.0)	0.005	−0.51 (0.18)	0.005	−0.42 (0.19)	0.026
Sleep efficiency (%), median (interquartile)c	86.2 (80.0, 88.9)	87.2 (81.6, 90.0)	0.191	−0.02 (0.01)	0.123	−0.02 (0.01)	0.210
WASO (minutes), median (interquartile)	54.6 (42.1, 75.2)	50.9 (35.4, 75.6)	0.361	0.09 (0.10)	0.339	0.11 (0.10)	0.274
Average awakening length (minutes), median (interquartile)c	4.7 (3.2, 7.2)	4.7 (3.5, 6.6)	0.921	−0.002 (0.09)	0.985	−0.06 (0.09)	0.531
Number of awakenings, median (interquartile)c	14.4 (11.6, 18.4)	13.6 (10.4, 17.7)	0.565	0.03 (0.08)	0.701	0.08 (0.08)	0.366

Notes: Depression was defined using the PHQ-8 score ≥10.

a Student’s t-tests were conducted for parametric variables with mean, and Kruskal–Wallis tests were conducted for nonparametric variables with median.

b Models were adjusted for women’s body mass index (continuous), marital status, current smoking status, education level, and children’s disability group.

c Log transformation was made for nonparametric variables in the linear regression models.

d For actigraphy-measured sleep parameters, the number of depressed women was 44, while the number of nondepressed women was 127. P-values less than 0.05 are shown in bold.

Abbreviations: SE, standard error; PSQI, Pittsburgh Sleep Quality Index; WASO, wake after sleep onset; PHQ-8, eight-item Patient Health Questionnaire.

Table 3 Differences in subjective sleep parameters between depressed and nondepressed women (PHQ-8 excluded item 3: trouble sleeping)

Dependent variables	Depressed (n=32)	Nondepressed (n=143)	P-valuea	Univariate models		Multivariable modelsb
				β (SE)	P-value	β (SE)	P-value
Subjective: PSQI-reported sleep parameters
Total time in bed (hours), mean (SD)	6.3 (1.4)	7.3 (1.6)	0.001	−1.00 (0.30)	0.001	−0.98 (0.31)	0.002
Sleep latency (minutes), median (interquartile)c	52.5 (20.0, 75.0)	30.0 (10.0, 60.0)	0.021	0.45 (0.22)	0.041	0.30 (0.22)	0.184
Sleep duration (hours), mean (SD)	5.5 (1.2)	6.6 (1.4)	<0.001	−1.12 (0.27)	<0.001	−1.02 (0.27)	<0.001
Sleep efficiency (%), median (interquartile)c	88.9 (78.7, 100.0)	91.7 (77.8, 100.0)	0.907	−0.02 (0.03)	0.497	−0.01 (0.03)	0.692
Global PSQI score, median (interquartile)c	11.5 (9.0, 14.0)	7.0 (5.0, 9.0)	<0.001	0.52 (0.09)	<0.001	0.47 (0.09)	<0.001

Notes: Depression was defined using the PHQ-8 score ≥10.

a Student’s t-tests were conducted for parametric variables with mean, and Kruskal–Wallis tests were conducted for nonparametric variables with median.

b Models were adjusted for women’s body mass index (continuous), marital status, current smoking status, education level, and children’s disability group.

c Log transformation was made for nonparametric variables in the linear regression models. P-values less than 0.05 are shown in bold.

Abbreviations: PHQ-8, eight-item Patient Health Questionnaire; SE, standard error; PSQI, Pittsburgh Sleep Quality Index.