Association of Chronotypes and Sleep Disturbance with Perceived Job Stressors and Stress Response: A Covariance Structure Analysis

Figures & data

Table 1 Characteristics of the Subjects and Their Correlation with PPSR Scores on BJSQ or Effects on PPSR Scores

Characteristics	Value (Number or Mean ± SD)	Correlation with PPSR Score (r) or Effects on PPSR Score (Mean ± SD, t-test)
Age	41.2 ± 11.9	r = −0.094, p = 0.030
Sex (men: women)	239: 296	Men: 49.9 ± 14.0 vs women: 54.3 ± 14.3, p < 0.001 (t-test)
Education, years	14.7 ± 1.8	r = −0.032, p = 0.456
Marital status (married: unmarried)	346: 185	Married: 50.4 ± 13.7 vs unmarried: 55.9 ± 14.9, p < 0.001 (t-test)
Living alone (yes: no)	112: 423	Yes: 54.4 ± 14.9 vs no: 51.8 ± 14.1, p = 0.088 (t-test)
Number of offspring	1.3 ± 1.3	r = −0.064, p = 0.143
Comorbidity of physical disease (yes: no)	101: 434	Yes: 52.1 ± 13.7 vs no: 52.4 ± 14.4, p = 0.085 (t-test)
First-degree relative with psychiatric disease (yes: no)	54: 431	Yes: 53.5 ± 13.6 vs no: 52.0 ± 14.3, p = 0.446 (t-test)

Notes: Data are presented as means ± SD or numbers. r = Pearson correlation coefficient.

Abbreviations: BJSQ, Brief Job Stress Questionnaire; PPSR, psychological and physical stress response.

Table 2 Characteristics of Adult Workers and Their Effects on PPSR

	Number of Subjects	Mean PPSR ± SD	ANOVA
Occupational contracts
Regular  Part-time  Temporary  Others	454 56 6 15	53.7 ± 14.7 55.2 ± 15.3 59.5 ± 18.1 50.3 ± 10.7	F(3, 527) = 0.758 p = 0.518
Job class
General class  Section manager class  Manager’s level or higher	388 63 7	54.1 ± 14.4 51.7 ± 15.7 41.9 ± 8.6	F(2, 455) = 3.113 p = 0.045
Working condition
Inflexible  Discretionary  Flexible  Shift work (not including night shift)  Shift work (including night shift)  Others	324 24 5 26 109 2	54.0 ± 14.7 45.1 ± 11.4 45.4 ± 11.8 57.1 ± 16.0 54.4 ± 14.0 32.5 ± 2.1	F(5, 484) = 3.256 p = 0.007
Overtime work hours (/month)
≤ 20 hours  21–40 hours  41–60 hours  ≥ 61 hours	358 74 29 16	54.2 ± 13.9 54.7 ± 17.6 52.8 ± 15.6 54.3 ± 17.6	F(3, 467) = 0.836 p = 0.584

Notes: Data are presented as means ± SD or numbers. Bonferroni test showed no significant difference between groups in job class and working condition.

Figure 1 Results of the path analysis. Path analysis of the data of 535 adult workers regarding Diurnal Type Scale (DTS) score, Pittsburgh Sleep Quality Index (PSQI) global score, perceived job stressors on the Brief Job Stress Questionnaire (BJSQ), and psychological and physical stress response (PPSR) on the BJSQ. The solid arrows represent statistically significant direct paths. The numbers beside the arrows show the standardized path coefficients (minimum: −1; maximum: 1). *p < 0.05, ***p < 0.001.

Table 3 Correlation (r) Between DTS, Sleep Disturbance (PSQI), Perceived Job Stressors, PPSR of BJSQ, Social Support of BJSQ, and Satisfaction of BJSQ

Measures mean ± SD	DTS score 18.8 ± 3.6	PSQI score 5.8 ± 3.5	Perceived job stressors of BJSQ 40.6 ± 6.2	PPSR of BJSQ 52.4 ± 14.3	Social support of BJSQ 19.2 ± 5.4	Satisfaction of BJSQ 5.8 ± 1.3
DTS score		r = −0.240 p < 0.001	r = −0.083 p = 0.054	r = −0.187 p < 0.001	r = −0.064 p = 0.140	r = 0.087 p = 0.045
PSQI score			r = 0.242 p < 0.001	r = 0.498 p < 0.001	r = 0.318 p < 0.001	r = −0.294 p < 0.001
Perceived job stressors of BJSQ				r = 0.440 p < 0.001	r = 0.334 p < 0.001	r = −0.375 p < 0.001
PPSR of BJSQ					r = 0.368 p < 0.001	r = −0.430 p < 0.001
Social support of BJSQ						r = −0.566 p < 0.001

Notes: For satisfaction of BJSQ, high scores indicate high satisfaction. For other subitems of BJSQ, higher the total score, the higher the stress.

Abbreviations: DTS, Diurnal Type Scale; PSQI, Pittsburgh Sleep Quality Index; BJSQ, Brief Job Stress Questionnaire; PPSR, psychological and physical stress response.

Table 4 Standardized Path Coefficients Between Each Variable

From	Direct Effect on
	Job Stressors	Sleep Disturbance (PSQI)	PPSR
Diurnal Type Scale	−0.083*	−0.222***	−0.064*
Job stressors		0.223***	0.328***
PSQI			0.421***
	Indirect effect on
	Job stressors	Sleep disturbance (PSQI)	PPSR
Diurnal Type Scale	via Job stressors	−0.019	−0.027
	via PSQI		−0.093***
	via Job stressors + PSQI		−0.008
	Total indirect effect		−0.129***
Job stressors	via PSQI		0.094***
	Total effect on
	Job stressors	Sleep disturbance (PSQI)	PPSR
Diurnal Type Scale	−0.238***	−0.240***	−0.193***
Job stressors		–	0.422***

Notes: *p < 0.05, ***p < 0.001.

Abbreviations: PSQI, Pittsburgh Sleep Quality Index; PPSR, psychological and physical stress response.