Sleep disturbances among Swedish soldiers after military service abroad

Figures & data

Table 1. Characteristics of the population before adjustment (% and mean ± SD).

	Military (n = 1080)	Control (n = 26,723)	p value
Men	89.4	45.3	<0.0001
Age	36.1 ± 9.9	43.8 ± 16.1	<0.0001
BMI	25.6 ± 3.4	24.8 ± 4.4	<0.0001
Ever having had asthma	12.6	10.1	0.01
Smoking history			<0.0001
Never	79.0	60.6
Ex	14.1	25.4
Current	6.9	14.0
Oral tobacco (moist snuff)	27.5	10.8	<0.0001
Educational level			<0.0001
No university education	33.4	50.1
University less than 3 years	30.7	14.0
University 3 years or more	35.8	35.9
Physical exercise			<0.0001
Less than twice a week	24.6	49.3
Two to three times a week	40.9	32.5
More than three times a week	34.6	18.2

Table 2. Prevalence of sleep disturbances (at least three times a week) before and after propensity score matching^a (%).

	Before adjustment		After matching
	Military (n = 1080)	Controls (n = 26,723)	Military (n = 1030)	Controls (n = 1030)	p value after adjustment
Snoring	16.3	16.1	16.3	14.0	0.50
Difficulty inducing sleep	13.1	13.3	13.1	11.0	0.86
Difficulty maintaining sleep	15.5	27.6	15.6	18.5	0.11
Early morning awakenings	8.7	14.3	8.7	11.2	0.08
Insomnia^b	26.2	37.3	26.2	30.4	0.047
Excessive daytime sleepiness	22.7	29.4	22.7	27.9	0.01

a Matched for age, gender, ever having had asthma, body mass index, smoking, oral tobacco, educational level, and physical activity level.

b Insomnia = difficulty inducing sleep, difficulty maintaining sleep, and/or early morning awakenings.

Table 3. Determinants of sleep disturbances. Adjusted odds ratio (95% confidence interval), i.e. for the whole group, veterans, and control group, except in military service abroad.

	Snoring	DIS	DMS	EMA	Insomnia	EDS
Military assignment	1.00 (0.83–1.19)	1.10 (0.91–1.34)	0.77 (0.64–0.91)	0.89 (0.71–1.11)	0.82 (0.71–0.95)	0.74 (0.63–0.86)
Women	0.49 (0.45–0.53)	1.46 (1.35–1.58)	1.53 (1.44–1.62)	1.32 (1.23–1.43)	1.46 (1.38–1.54)	1.37 (1.30–1.46)
Age (per 10 years)	1.25 (1.23–1.29)	0.91 (0.88–0.93)	1.29 (1.26–1.31)	1.25 (1.22–1.28)	1.18 (1.15–1.19)	0.77 (0.76–0.79)
BMI (per 5 units)	1.73 (1.66–1.80)	1.13 (1.09–1.18)	1.12 (1.09–1.16)	1.13 (1.09–1.18)	1.1 (1.08–1.15)	1.17 (1.14–1.21)
Ever having had asthma	1.28 (1.15–1.41)	1.48 (1.34–1.63)	1.29 (1.19–1.41)	1.50 (1.36–1.66)	1.37 (1.27–1.48)	1.47 (1.36–1.59)
Smoking history
Never	1	1	1	1	1	1
Ex	1.39 (1.27–1.51)	1.28 (1.17–1.41)	1.34 (1.25–1.43)	1.32 (1.21–1.43)	1.33 (1.25–1.42)	1.27 (1.19–1.37)
Current	1.92 (1.73–2.12)	2.14 (1.94–2.36)	1.12 (1.03–1.22)	1.31 (1.18–1.46)	1.32 (1.22–1.43)	1.43 (1.32–1.55)
Oral tobacco (moist snuff)	1.28 (1.15–1.41)	1.65 (1.48–1.83)	0.74 (0.67–0.82)	0.81 (0.72–0.92)	1.02 (0.94–1.11)	1.11 (1.02–1.22)
Educational level
No university education	1	1	1	1	1	1
University less than 3 years	0.99 (0.89–1.10)	0.82 (0.73–0.90)	1.00 (0.92–1.09)	0.82 (0.73–0.91)	0.96 (0.89–1.04)	1.02 (0.94–1.11)
University 3 years or more	0.93 (0.86–1.01)	0.73 (0.67–0.80)	1.07 (1.00–1.14)	0.80 (0.74–0.87)	0.95 (0.90–1.01)	1.03 (0.97–1.10)
Physical exercise
Less than twice a week	1	1	1	1	1	1
Two to three times a week	0.81 (0.75–0.88)	0.83 (0.76–0.90)	0.86 (0.80–0.92)	0.86 (0.80–0.94)	0.86 (0.81–0.92)	0.76 (0.71–0.81)
More than three times a week	0.74 (0.66–0.81)	0.97 (0.88–1.07)	0.99 (0.92–1.07)	1.00 (0.90–1.10)	0.99 (0.92–1.06)	0.78 (0.72–0.84)

Adjusted for all the variables in the table and a history of asthma.

DIS = difficulty inducing sleep; DMS = difficulty maintaining sleep; EDS = excessive daytime sleepiness; EMA = early morning awakenings.

Table 3. Prevalence of sleep disturbances (at least three times a week) in subjects who had been assigned to Kosovo and Afghanistan (%) and adjusted^a odds ratios for having sleep disturbances after having been assigned to Afghanistan compared with assignment to Kosovo.^b

	Kosovo (n= 369)	Afghanistan (n = 371)	Odds ratio (95% CI)	p value after adjustment
Snoring	19.0	13.5	0.82 (0.53–1.26)	0.36
Difficulty inducing sleep	11.6	11.6	1.01 (0.63–1.63)	0.96
Difficulty maintaining sleep	18.8	12.9	0.76 (0.50–1.16)	0.20
Early morning awakenings	9.0	8.4	0.99 (0.58–1.70)	0.98
Insomnia^c	28.7	22.6	0.81 (0.58–1.14)	0.23
Excessive daytime sleepiness	24.8	22.4	1.01 (0.70–1.45)	0.97

a Matched for age, gender, ever having had asthma, body mass index, smoking, oral tobacco, educational level, and physical activity level.

b Participants who had been on missions to both Kosovo and Afghanistan were omitted from this analysis.

c Insomnia = difficulty inducing sleep, difficulty maintaining sleep, and/or early morning awakenings.