Original article
Social determinants of self-reported sleep problems in South Korea and Taiwan,☆☆

https://doi.org/10.1016/j.jpsychores.2010.04.014Get rights and content

Abstract

Objective

To clarify the social determinants of insomnia in South Korea and Taiwan.

Methods

Cross-sectional surveys were conducted in South Korea (n=1007) and Taiwan (n=785) in 2003. Nationwide samples of people completed a structured questionnaire, based on face-to-face interviews. Outcome measures were self-reported sleep problems, defined by at least one of three sleep symptoms on a nightly basis for more than 2 weeks: difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), and early morning waking (EMW). Explanatory variables investigated were demographic characteristics (gender, age), socioeconomic factors (income, education), and social capital, including norms of reciprocity, interpersonal trust, civic association, and social support (i.e., the availability of persons to consult regarding personal problems and important matters).

Results

The prevalence of sleep problems was 8.2% in South Korea and 9.3% in Taiwan. Stepwise logistic regression showed that, in South Korea, sleep problems were significantly associated with increasing age (P<.05), low income (P<.01), and having few persons with whom to consult compared to having a spouse/partner (P<.05); in Taiwan, sleep problems were significantly associated with being female (P<.05), increasing age (P<.001), and having family members vs. a spouse/partner to consult (P<.05).

Conclusion

Self-reported sleep problems in two northeast Asian countries were associated with certain demographic characteristics and socioeconomic factors, which is consistent with previous results in Western countries. In addition, the results of this study suggested that sleep problems may also be associated with social support.

Introduction

A single-day survey performed in 10 industrialized countries estimated that one in four individuals does not sleep well [1]. Insomnia, one of the most frequently reported health problems in the general population, has drawn public attention and, in response to public concern, many scientific studies have been conducted on the etiology of insomnia. Previous reports generally agree that psychological disorders [2] and physiological illnesses, including obstructive sleep apnea syndrome [3], obesity [4], and cardiovascular malfunction [5], are closely related to insomnia.

In addition, several epidemiological studies have suggested that insomnia is associated with social factors including ethnicity [6], gender (i.e., being female), age (i.e., older age) [7], [8], [9], [10], [11], [12], and socioeconomic status (i.e., low income or low educational attainment) [13], [14]. However, the majority of these studies were conducted in Western countries and appropriate empirical evidence is lacking for Asia. Furthermore, the majority of these epidemiological studies also failed to demonstrate the mechanisms underlying the reported associations. Nevertheless, two recent studies have suggested the mechanism by which socioeconomic status affects sleep problems. Moore et al. [15] reported that higher education was associated with higher income and that higher income was associated with better physical and psychological health. Van Cauter and Spiegel [16] reported that low socioeconomic status was associated with diminished opportunities to obtain sufficient sleep or with environmental conditions that compromise sleep quality.

Likewise, in consideration of the relationship between sleep problems and social factors, we focused particularly on social capital as one of the factors mediating sleep problems. Social capital refers to social connections within and between human networks, and many epidemiological studies conducted during the past few decades have suggested that this factor positively affects both health and well-being [17], [18], [19], [20], [21], [22]. Social capital operates through civil society, which consists of “private organizations that are formed and sustained by groups of people acting voluntarily and without seeking personal profit to provide benefits for themselves or for others” [21], [23], [24]. These voluntary associations also connect people with one another, build trust and reciprocity, and consolidate society on the basis of a sense of altruism rather than obligation. We assumed that people become socially isolated under circumstances in which social capital is less available and that such individuals are at increased risk for insomnia because of their limited access to resources such as medical care, information, and emotional support.

Thus, the purpose of this study was twofold: (1) to investigate the social determinants of sleep problems in two northeastern Asian countries, South Korea and Taiwan; and (2) to clarify whether social capital is associated with sleep problems.

Section snippets

Population and samples

Data were collected from cross-sectional surveys conducted in South Korea and Taiwan in 2003 as part of “A Study of Statistical Science on Health and Culture.” These data have been reported in part elsewhere [25], but here we investigate a new hypothesis using data that were not previously examined. The target populations were adults (aged ≥20 years) residing in each country. The survey involved a face-to-face interview by well-trained interviewers using a semistructured questionnaire that was

Results

The number of valid questionnaires returned was 1007 in South Korea (complete sample) and 785 in Taiwan (response rate=44%). Table 1 shows the basic characteristics of subjects in relation to self-reported sleep symptoms. The prevalence of self-reported sleep problems was 8.4% (5.4% for DIS, 5.1% for DMS, and 4.4% for EMW) in South Korea, compared to 9.3% (6.8% for DIS, 3.6% for DMS, and 3.8% for EMW) in Taiwan. Regardless of country, people who were female, older and with lower income or

Discussion

This study sought to assess the social determinants of self-reported sleep problems in South Korea and Taiwan. Sleep problems in these two northeastern Asian countries were associated with demographic characteristics, socioeconomic factors, and social support. We discuss the results of the present study in light of its strengths and limitations below.

A meta-analysis showed that women were more likely to report insomnia than were men [7], [6], but the majority of the individual studies included

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  • Cited by (0)

    Competing interests: The researchers have no financial conflicts of interest.

    ☆☆

    Funding: This study was supported by the Ministry of Education, Culture, Sports, Science and Technology through a Grant in Scientific Research B(2) no. 14402043 (fiscal years 2002–2004) and no. 18402001 (fiscal years 2006–2008).

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