Network analysis of smoking-related sleep characteristics in Chinese adults

Figures & data

Table 1. Characteristics of participants by smoking status.

Characteristics	All participants (N = 5228)	Smoking status
		Non-smokers (N = 4340)	Current smokers (N = 744)	Former smokers (N = 144)
Age (years), median (IQR)	44 (34-52)	44 (33-53)	44 (35-52)	48 (38-54)**
Sex
Women	2511 (48.03)	2477 (57.07)	24 (3.23)*	10 (6.94)**
Men	2717 (51.97)	1863 (42.93)	720 (96.77)*	134 (93.06)**
Education
Low	2941 (60.69)	2455 (60.41)	419 (63.87)	67 (53.17)
High	1905 (39.31)	1609 (39.59)	237 (36.13)	59 (46.83)
Marital status
Married	3866 (79.78)	3185 (78.37)	571 (87.04)*	110 (87.30)**
Unmarried	980 (20.22)	879 (21.63)	85 (12.96)*	16 (12.70)**
Region
Gansu	3020 (57.77)	2374 (54.70)	534 (71.77)*	112 (77.78)**
Henan	1766 (33.78)	1634 (37.65)	115 (15.46)*	17 (11.81)**
Other	442 (8.45)	332 (7.65)	95 (12.77)*	15 (10.42)**
Alcohol consumption
≤ 15 g ethanol/day	5059 (97.29)	4283 (99.03)	654 (89.10)*	122 (86.52)**
> 15 g ethanol/day	141 (2.71)	42 (0.97)	80 (10.90)*	19 (13.48)**
Physical activity
Active	3461 (66.71)	2792 (64.76)	556 (75.54)*	113 (80.14)**
Inactive	1727 (33.29)	1519 (35.24)	180 (24.46)*	28 (19.86)**
Depressive symptoms
No	3551 (70.96)	2976 (71.03)	480 (70.28)	95 (72.52)
Yes	1453 (29.04)	1214 (28.97)	203 (29.72)	36 (27.48)
Anxiety symptoms
No	4756 (95.12)	3986 (95.22)	650 (95.17)	120 (91.60)
Yes	244 (4.88)	200 (4.78)	33 (4.83)	11 (8.40)
History of chronic diseases^†
No	4420 (91.34)	3767 (92.62)	551 (85.29)*	102 (80.95)**
Yes	419 (8.66)	300 (7.38)	95 (14.71)*	24 (19.05)**

Data are given as median (IQR) or number (%).

* p < 0.001 comparing nonsmokers with current smokers.

** p < 0.05 comparing nonsmokers with former smokers.

^† History of chronic diseases included chronic obstructive pulmonary disease, asthma, cardiovascular disease, hypertension, diabetes, and cancer.

Table 2. Associations between sleep characteristics and smoking status.

Sleep Characteristics	Current smokers (N = 744) (ref = nonsmokers)		Former smokers (N = 144) (ref = nonsmokers)
	N	AOR (95% CI)^†	N	AOR (95% CI)^†
Short sleep duration
No	451	1.00	85	1.00
Yes	293	1.13 (0.92-1.38)	59	1.12 (0.76-1.65)
Long nap time
No	691	1.00	131	1.00
Yes	53	1.51 (1.03-2.23)*	13	2.11 (1.10-4.06)*
Difficulty falling asleep
No	621	1.00	126	1.00
Yes	123	1.66 (1.25-2.21)*	18	1.01 (0.56-1.80)
Late bedtime
No	538	1.00	112	1.00
Yes	206	1.58 (1.24-2.00)*	32	1.29 (0.80-2.08)
Getting up after 7 am
No	358	1.00	79	1.00
Yes	386	1.36 (1.11-1.68)*	65	1.10 (0.74-1.64)
Difficulty maintaining sleep
No	705	1.00	138	1.00
Yes	39	1.15 (0.71-1.88)	6	0.64 (0.24-1.68)
Waking up earlier than expected
No	703	1.00	134	1.00
Yes	41	2.02 (1.22-3.34)*	10	2.97 (1.33-6.63)*
Use of sleep medication
No	720	1.00	137	1.00
Yes	24	0.58 (0.33-1.02)	7	0.86 (0.35-2.10)

Abbreviations: AOR = adjusted odds ratio, CI = confident interval.

^† Adjusted for age, sex, education, marital status, resident region, alcohol consumption, physical activity, depressive symptoms, and anxiety symptoms.

^* p value < 0.05.

Table 3. Associations between sleep characteristics and smoking intensity.

Sleep Characteristics	Current light smokers (N = 436) (ref = nonsmokers)		Current heavy smokers (N = 308) (ref = nonsmokers)		Former light smokers (N = 100) (ref = nonsmokers)		Former heavy smokers (N = 44) (ref = nonsmokers)
	N	AOR (95% CI)^†	N	AOR (95% CI)^†	N	AOR (95% CI)^†	N	AOR (95% CI)^†
Short sleep duration
No	267	1.00	184	1.00	54	1.00	31	1.00
Yes	169	1.15 (0.90-1.47)	124	1.12 (0.83-1.51)	46	1.4 (0.89-2.19)	13	0.61 (0.29-1.28)
Long nap time
No	407	1.00	284	1.00	90	1.00	41	1.00
Yes	29	1.45 (0.91-2.31)	24	1.67 (0.97-2.87)	10	2.37 (1.14-4.94)*	3	1.45 (0.40-5.31)
Difficulty falling asleep
No	364	1.00	257	1.00	87	1.00	39	1.00
Yes	72	1.56 (1.11-2.19)*	51	1.72 (1.14-2.59)*	13	0.97 (0.50-1.90)	5	1.24 (0.43-3.61)
Late bedtime
No	316	1.00	222	1.00	80	1.00	32	1.00
Yes	120	1.30 (0.98-1.72)	86	2.16 (1.52-3.06)*	20	0.92 (0.52-1.64)	12	2.94 (1.30-6.65)*
Getting up after 7 am
No	207	1.00	151	1.00	56	1.00	23	1.00
Yes	229	1.14 (0.89-1.46)	157	1.81 (1.34-2.44)*	44	1.02 (0.64-1.63)	21	1.25 (0.62-2.51)
Difficulty maintaining sleep
No	415	1.00	290	1.00	95	1.00	43	1.00
Yes	21	1.20 (0.67-2.14)	18	1.05 (0.53-2.08)	5	0.75 (0.26-2.16)	1	0.40 (0.05-3.52)
Waking up earlier than expected
No	413	1.00	290	1.00	93	1.00	41	1.00
Yes	23	2.03 (1.13-3.64)*	18	1.99 (0.99-4.02)	7	2.49 (0.97-6.35)	3	3.72 (0.87-15.98)
Use of sleep medication
No	421	1.00	299	1.00	94	1.00	43	1.00
Yes	15	0.66 (0.34-1.28)	9	0.39 (0.17-0.91)	6	1.06 (0.41-2.76)	1	0.32 (0.03-3.03)

Abbreviations: AOR: adjusted odds ratio, CI: confident interval.

^† Adjusted for age, sex, education, marital status, resident region, alcohol consumption, physical activity, depressive symptoms, and anxiety symptoms.

* P value < 0.05.

Figure 1. Estimated network structure and centrality plot of smoking-related sleep characteristics among the overall population.

Abbreviations: Bed = late bedtime, Diff = difficulty falling asleep, Early = waking up earlier than expected, Getup = getting up after 7 am, Nap = long nap time.

Note. In the left panel displaying the estimated network structure, blue edges indicate positive effects and red edges indicate negative effects. In the right panel displaying the centrality plot, the y-axis shows the node name order by strength, the x-axis is the centrality value (standardized z-scores), the closeness of node’Nap’is missing because it is not connected to other nodes.

Data availability statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.