Sleep difficulty by occupation: a Korean nationwide survey

Article information

J Med Life Sci. 2024;21(3):131-134

Publication date (electronic) : 2024 September 30

doi : https://doi.org/10.22730/jmls.2024.21.3.131

Heuy Sun Suh ¹

, In Cheol Hwang^,¹

, Hong Yup Ahn ²

¹Department of Family Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Republic of Korea

²Department of Statistics, Dongguk University, Seoul, Republic of Korea

Correspondence to In Cheol Hwang Department of Family Medicine, Gil Medical Center, Gachon University College of Medicine, 21 Namdong-daero 774beon-gil, Namdong-gu, Incheon 21565, Republic of Korea Tel: 82-32-460-3591 Fax: 82-32-460-3591 E-mail: spfe0211@gmail.com

Received 2024 May 16; Revised 2024 June 20; Accepted 2024 June 21.

Keywords: Occupations; Sleep; Sleep quality

Sleep problems are critical in occupational medicine due to their impact on job performance and safety [1]. Previous research has primarily focused on specific occupations (e.g., shift workers) or periods (e.g., coronavirus disease 2019 [COVID-19] pandemic), with limited data on overall sleep health across different occupations. Cultural variations in sleep perceptions and occupational characteristics underscore the need for population-specific studies.

To address this gap, we conducted a nationwide pilot study examining sleep difficulty by occupation in Korea. Using data from the 2019 Korea National Health and Nutrition Examination Survey, a nationally representative annual survey, we included 3,278 employed adults aged 19 and over, excluding those with missing sleep data or diagnosed with depression, cardiovascular disease (i.e., myocardial infarction, stroke), or cancer.

Sleep difficulty was assessed using the Korean health-related quality of life instrument, with ‘moderate’ or ‘severe’ sleep difficulty defined as ‘substantial.’ Occupations were categorized into six groups based on a previous study [2]: 1) managers, 2) office workers, 3) service and sales (S-S) workers, 4) agricultural and fishery industry workers, 5) skilled manual laborers, or 6) simple manual laborers. Detailed covariate information is presented in Table 1.

Table 1.

Participant characteristics by occupation

We estimated the prevalence of substantial sleep difficulty in each occupation group using multivariate logistic regression adjusted for relevant covariates. Each group was compared to the combined remaining five groups (e.g., managers vs. non-managers). Analyses were conducted using Stata/MP version 17.0 (StataCorp, College Station, TX, USA), with two-sided tests and a significant level of P<0.05. All participants signed an informed consent form, and the study protocol was approved by the Institutional Review Board of Gachon University Gil Medical Center (No. GCIRB2023-100).

Overall, 6.8% of participants experienced substantial sleep difficulty. Most participant characteristics varied across occupation groups (Table 1). Fig. 1 presents the estimated prevalence of substantial sleep difficulty per occupation. S-S workers exhibited a significantly higher prevalence of sleep difficulty compared to non-S-S workers (6.3% vs. 4.2%; odds ratio, 1.53; P=0.024).

Figure 1.

Prevalence of substantial sleep difficulty by occupation. Estimated proportions were adjusted for demographics (age, sex, economic status, education, and marital status), health behaviors (body mass index, current smoking, binge drinking, and aerobic exercise), comorbidities (hypertension and type 2 diabetes), mental health (stress and depression), and sleep duration. The other jobs group represents participants in all occupations except the corresponding job group.

Our finding of increased sleep difficulty among S-S workers contrasts with a previous Korean study reporting lower psychological well-being in this group compared to managers [3]. However, unlike our study’s more inclusive reference (comparator) group, their comparison group (managers) had the highest stress levels (Table 1). The rate of stressed mental health status was highest among managers. In contrast, our study employed a more informative reference group consisting of a combined representation of all other occupation groups.

The elevated rate of sleep difficulty among S-S workers is unsurprising given the demands of emotional labor. Frequent exposure to customer complaints and expectation of emotional suppression can lead to emotional dissonance, a known risk factor for burnout, depressive mood, and subsequent sleep disturbances. Previous research has linked discrimination, customer confrontation, and emotional labor to increased sleep difficulty among workers [4]. Furthermore, job insecurity and low rewards contribute to psychological distress among Korean S-S workers [5].

This study’s limitations include a lack of detailed characteristics for sleep (e.g., sleep quality by a standardized questionnaire, sleep duration using actigraphy or polysomnography) and occupational specifics, which could confound the association between occupation and sleep difficulty. Additionally, healthy worker bias may have underestimated sleep difficulty rates.

Despite these limitations, our findings highlight the need for workplace health initiatives. Screening for sleep problems, especially among S-S workers, and implementing strategies to reduce risk factors (e.g., scheduled breaks) are crucial steps toward promoting employee well-being.

Acknowledgements

This work was supported by the Gachon University Gil Medical Center (Grant no., FRD2021-14).

References

1. Åkerstedt T, Mittendorfer-Rutz E, Rahman S. Sleep disturbance and work-related mental strain: a national prospective cohort study of the prediction of subsequent long-term sickness absence, disability pension and mortality. Scand J Public Health 2020;48:888–95.

2. Choi SB, Yoon JH, Lee W. The Modified International Standard Classification of Occupations defined by the clustering of occupational characteristics in the Korean Working Conditions Survey. Ind Health 2020;58:132–41.

3. Park J, Oh YS, Kim Y. Psychological well-being of South Korean employees in different occupational classes. Arch Environ Occup Health 2021;76:348–60.

4. Kim G, Min B, Jung J, Paek D, Cho SI. The association of relational and organizational job stress factors with sleep disorder: analysis of the 3rd Korean working conditions survey (2011). Ann Occup Environ Med 2016;28:46.

5. Suh C, Punnett L. High emotional demands at work and poor mental health in client-facing workers. Int J Environ Res Public Health 2022;19:7530.

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This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Figure 1.

Table 1.

Participant characteristics by occupation

	Managers (n=771)	Office workers (n=643)	Service & sales workers (n=673)	Agricultural-fishery industry workers (n=143)	Skilled manual laborers (n=575)	Simple manual laborers (n=473)	P-value
Demographics
Age (years)	41.4 (11.4)	42.4 (10.8)	45.9 (14.8)	63.4 (10.5)	50.2 (12.2)	59.2 (14.9)	<0.001
Female sex	372 [18.3]	336 [52.3]	428 [63.6]	51 [35.7]	97 [16.9]	276 [58.4]	<0.001
Low income^*	158 [20.5]	119 [18.5]	259 [38.5]	95 [66.4]	205 [35.7]	281 [59.9]	<0.001
Middle school graduate or less	7 [0.9]	7 [1.1]	117 [17.4]	95 [66.4]	159 [27.7]	244 [51.6]	<0.001
Unmarried^†	229 [29.7]	172 [26.8]	235 [34.9]	12 [8.4]	111 [19.3]	154 [32.6]	<0.001
Health-related behavior
Body mass index (kg/m²)	23.8 (3.6)	23.7 (3.7)	24.1 (3.6)	24.4 (3.2)	24.7 (3.6)	24.2 (3.5)	<0.001
Current smoker	123 [16.0]	123 [19.1]	140 [20.8]	27 [18.9]	197 [34.3]	86 [18.2]	<0.001
Daily binge drinking^‡	22 [3.4]	36 [6.5]	37 [7.0]	12 [12.1]	47 [9.5]	22 [6.8]	<0.001
Aerobic exercise^§	382 [50.0]	310 [48.2]	325 [48.4]	52 [36.6]	240 [41.7]	206 [43.7]	0.005
Co-morbidities
Hypertension	73 [9.5]	65 [10.1]	121 [18.0]	62 [43.4]	125 [21.7]	177 [37.4]	<0.001
Type 2 diabetes	36 [4.7]	19 [3.0]	42 [6.2]	25 [17.5]	57 [9.9]	55 [11.6]	<0.001
Mental health
Stressed^‖	279 [36.2]	206 [32.0]	185 [27.5]	26 [18.2]	146 [25.4]	103 [21.8]	<0.001
Depressed mood^**	54 [7.0]	55 [8.6]	55 [8.2]	14 [9.8]	39 [6.8]	52 [11.0]	0.131
Sleep duration (hours per day)	6.6 (1.1)	6.6 (1.1)	6.6 (1.3)	6.6 (1.5)	6.5 (1.1)	6.4 (1.4)	0.109
Substantial sleep difficulty	47 [6.1]	35 [5.4]	59 [8.8]	11 [7.7]	30 [5.2]	40 [8.5]	0.049

Values are presented as mean (standard deviation) or number [%]. P-values were obtained from analysis of variance (continuous variables) or chi-squared tests (categorical variables).

Below the median household income of the study participants,

^†

Included being single or separated for any reason,

^‡

Consuming seven or more drinks (male) or five or more drinks (female) in one session,

^§

More than 2.5 hours/week of moderate-intensity activity, more than 1.25 hours/week of high-intensity activity, or a combination of both,

^‖

Feeling stressed ‘a lot’ or ‘fairly often’, and

^**

Feeling depressed for >2 consecutive weeks.