Abstract
Study Objectives:
The present study was conducted to clarify the prevalence of non-pharmacological self-management (nPSM) practices for obtaining good sleep and to identify favorable nPSM practices that could be applied for reducing excessive daytime sleepiness (EDS). We analyzed epidemiological data for an authentic representative sample of the Japanese population.
Methods:
Data obtained from 24,686 adults via a self-administered questionnaire completed in the Active Survey of Health and Welfare 2000 were used for analyses. The prevalence of individual nPSM practices was calculated by gender. Subsequently, the associations between such practices and EDS were examined using logistic regression analyses.
Results:
“Having a bath” was the most prevalent nPSM practice for both men (59.0%) and women (64.4%), followed by “maintaining a regular schedule” (men: 49.0%, women: 58.6%), “reading or listening to music” (men: 43.4%, women: 49.4%), “snacking on food and/or beverages” (men: 36.1%, women: 27.9%), and “exercising” (men: 26.2%, women: 29.4%). The prevalence of “maintaining a regular schedule” increased with age. Multiple logistic regression analyses revealed that having a bath and maintaining a regular schedule had negative associations with EDS, whereas snacking on food and/or beverages had a positive association.
Conclusions:
Having a bath and maintaining a regular schedule were identified as favorable nPSM practices for reducing EDS, whereas snacking on food and/or beverages was considered to be an unfavorable nPSM practice.
Citation:
Aritake-Okada S; Kaneita Y; Uchiyama M; Mishima K; Ohida T. Non-pharmacological self-management of sleep among the japanese general population. J Clin Sleep Med 2009;5(5):464-469
Keywords: Self-management, sleep, Japan, epidemiology, excessive daytime sleepiness, prevalence
Sleep disturbance is known to be associated with the onset of mental disorders such as depression. It is also well known that sleep disturbance is an eventual risk factor for various somatic disorders such as diabetes mellitus, obesity, and cardiovascular disease.1–5 In addition, excessive daytime sleepiness (EDS) resulting from sleep disturbance may lead to industrial and traffic accidents.6–8 Thus, in developed countries, employing pertinent measures to prevent sleep disturbance is widely recognized as an important issue in promoting industrial hygiene and public health.
People in general use various non-pharmacological self-management (nPSM) strategies to obtain good sleep. However, most previous studies have focused on so-called pharmacological management practices such as the use of alcohol or hypnotic medications, and many epidemiological findings regarding such practices have been reported. For example, a study in the US reported that the prevalence of using hypnotic medications to improve the quality and quantity of sleep ranged from 10% to 18%, while that of consuming alcohol ranged from 10% to 13%, with the use of hypnotic medications being more prevalent among women and the consumption of alcoholic beverages more prevalent among men.9 A study in Japan obtained similar findings with respect to the use of hypnotics (women: 5.9%, men: 4.3%),10 and to the larger proportion of men consuming alcoholic beverages to induce sleep one or more times a week compared to women (48.3% and 18.3%, respectively).10 Although physiological data associated with nPSM practices such as exercising, having a bath, reading, or snacking on food and/or beverages have been reported, few findings of epidemiological studies are available. In a survey of self-management practices employed by Americans to obtain sleep, Ancoli-Israel et al. found that the prevalence of exercising was higher among non-insomniacs than among insomniacs.9 Morin et al. conducted a similar study of Americans and reported that the prevalence of reading was the highest, followed by listening to music.11 However, no epidemiological study of nPSM practices for obtaining good sleep has been conducted in any Asian country to date. Therefore, in this study, we examined nPSM practices employed by the Japanese by examining data from an authentic, substantially large, representative sample of the Japanese population. We also analyzed the associations between each nPSM practice and EDS in order to identify those nPSM practices reported to be most effective.
METHODS
Selection of Participants
The present study was part of a national survey (Active Survey of Health and Welfare) organized by the Statistics and Information Department of the Ministry of Health, Labour and Welfare of Japan. This national survey was planned in order to collect basic information on health and welfare, and included questions concerning symptoms of depression and sleep. The survey was conducted through health centers across Japan.
The survey was administered to subjects from 300 census precincts in Japan selected randomly from among some 824,000 precincts, which had been apportioned for equal population size. Each census precinct was numbered from north to south, and 300 precincts were selected by choosing precinct numbers at certain intervals. As a result, the sample represented the entire country. A health center with jurisdiction for each precinct was designated. Investigators sent by these health centers visited all households to distribute the questionnaires, and collected them a few days later. The survey targets were all individuals aged 12 years or older in the 300 sampled precincts. The survey was conducted simultaneously throughout Japan in June 2000. Oral informed consent was obtained from the participants, and their privacy was protected in accordance with Declaration of Helsinki guidelines.
Measures
A self-administered questionnaire was devised by 2 of the authors (M.U. and T.O.) together with an appropriate official of the Ministry of Health, Labour and Welfare. The questionnaire comprised 44 items, including items on (1) sociodemographic information such as age, gender, and community size; (2) general health status; (3) physical and psychological complaints; (4) information on mental stress; and (5) sleep habits and sleep problems, as well as (6) the Japanese version of the Center for Epidemiologic Studies Depression Scale (CES-D). The CES-D, which is a 20-item inventory designed specifically to assess symptoms of depression in the general population, was used to screen for current depressive states during the one week leading up to the survey. This questionnaire is adequately reliable and valid for use in a general population. The CES-D yields an item score (range, 0–3) and the sum of the 20-item scores (range 0–60). Higher scores indicate increasing severity of depressive symptoms. Although this scale is designed to screen, but not diagnose, major depression, a score ≥ 16 is highly suggestive of depressive symptoms. Shima et al. developed the Japanese version of the CES-D, examined its reliability and validity, and recommended that the cut-off point be set at 16, as is the case for the American version of the CES-D.12
The following questions regarding sleep experienced during the previous month (listed here followed by the variables they targeted) were embedded in the questionnaire:
Question: Did you indulge in any of the following practices in the past month in order to sleep efficiently?
(1) I consumed alcoholic beverages. [1 = No; 2 = 1-2 times a month; 3 = 1-2 times a week; 4 = 3 or more times a week]
(2) I used medications such as hypnotic drugs. [1 = No; 2 = 1-2 times a month; 3 = 1-2 times a week, 4 = 3 or more times a week]
(3) I snacked on food and/or beverages. [1 = No; 2 = Yes]
(4) I performed light exercise. [1. No, 2. Yes]
(5) I had a bath. [1. No, 2. Yes]
(6) I read or listened to music. [1. No, 2. Yes]
(7) I tried to maintain a regular schedule. [1. No, 2. Yes]
With regard to (1) and (2), participants who consumed alcohol and who used medications one or more times a week were categorized as participants who “consumed alcohol” and “used medication,” respectively.
With regard to sleep duration, we posed the question, “What was your average sleep duration per night?” Those who answered “less than 6 hours” were categorized as participants with “short sleep duration.”
For subjective sleep insufficiency, participants were asked to respond to the question, “Have you had sufficiently restful sleep?” by selecting one of the following 4 options: “Sufficient,” “Fairly sufficient,” “Rather insufficient,” and “Completely insufficient.” Those who selected the latter 2 options were categorized as participants with “subjective insufficient sleep”.
For excessive daytime sleepiness, we posed the question, “Have you experienced any difficulty in staying awake at times when you should not fall asleep (e.g., while you are driving)?” Those who responded affirmatively were classed as participants with “excessive daytime sleepiness.”
Statistical Analyses
Questionnaires were returned by 32,729 participants. The Ministry of Health, Labour and Welfare did not publish the number of residences contacted in the target communities, and therefore the return rate could not be calculated. However, the collection rates of similar investigations carried out 3, 4, and 6 years previously were 87.1%, 89.6%, and 87.3%, respectively. It can be assumed that since the present study was performed using similar methods, the collection rate is likely to have been similar to the previous investigations. The Minister of Health, Labour and Welfare granted permission for us to use the survey data. Before analysis, 707 participants who submitted blank answer forms were excluded from the study. Participants under 20 years of age (N = 3086) were also excluded since this study was aimed at adults. In addition, participants who had not responded to the questions on gender and/or age were excluded (N = 222), as were participants who omitted 6 or more answers on the CES-D (N = 4028). Thus, data for a total of 24,686 participants (11,752 men and 12,934 women) were analyzed statistically.
For statistical analysis, the prevalence of each nPSM practice (snacking on food and/or beverages, exercising, having a bath, reading or listening to music, and maintaining a regular schedule) used as a sleep aid was calculated by gender and by age class. The significance of the categorical data, such as the prevalence of each nPSM strategy used as a sleep aid, was analyzed using the χ2 test. Finally, logistic regression analyses were conducted to examine the factors associated with EDS by using 4 models with different adjustment factors. Model 1 was nonadjustable. Model 2 was adjustable, using gender, age class, place of residence, and severity of depression as covariates. In Model 3, short sleep duration and subjective insufficient sleep were added to the covariates of Model 2. In Model 4, consumption of alcohol and use of medication were further added to the covariates of Model 3.
Odds ratios were calculated from the univariate and multivariate logistic regression analyses with 95% confidence intervals. All analyses were performed using SPSS 12.0 for Windows (SPSS Inc., Chicago, IL)
RESULTS
Characteristics of the Participants
The demographic characteristics of the total 24,686 participants are shown in Table 1. Although the percentages of the men and women aged 70 years or older are slightly lower than those revealed by the census, the percentages of other groups are similar.
Table 1.
Demographic Characteristics of Analyzed Subjects in a Sample of the Japanese Adult General Population (N = 24,686)a
| Percentage in Age Group |
||||||
|---|---|---|---|---|---|---|
| Data Set | 20-29 y | 30-39 y | 40-49 y | 50-59 y | 60-69 y | 70+ y |
| Present study | ||||||
| Male (N = 11,752) | 18 | 18 | 19 | 21 | 15 | 9 |
| Female (N = 12,934) | 18 | 18 | 18 | 20 | 14 | 12 |
| Census | ||||||
| Male | 19 | 18 | 17 | 20 | 15 | 12 |
| Female | 17 | 16 | 16 | 19 | 15 | 17 |
Data for both the present study and the census were obtained in 2000.
Prevalence of Non-pharmacological Self-management Practices
The prevalence of each of the 5 nPSM practices classified by gender is shown in Table 2; the prevalence of “having a bath” was highest among both men (59.0%) and women (64.4%), followed by “maintaining a regular schedule” (men: 49.0%, women: 58.6%), “reading or listening to music” (men: 43.4%, women: 49.4%), “snacking on food and/or beverages” (men: 36.1%, women: 27.9%) and “exercising” (men: 26.2%, women: 29.4%). For all the nPSM practices, age-related differences were identified among both men and women (p < 0.001). In particular, the prevalence of maintaining a regular schedule increased with age, with respective prevalence in men and women in their 20s at 35.6% and 46.1% compared with that in men and women in their 70s at 68.1% and 69.8%. In terms of gender-based differences, the prevalence of snacking on food and/or beverages was significantly higher among men than women (p < 0.001). However, the prevalences of other nPSM practices were significantly higher among women than men (p < 0.001).
Table 2.
Non-Pharmacological Self-Management by Gender and Age Expressed as Percentage
| Age, y | N | Snacking on food and/or beverage,% | Exercising,% | Having a bath,% | Reading or listening to music,% | Maintaining a regular schedule,% |
|---|---|---|---|---|---|---|
| Male | ||||||
| 20-29 | 2151 | 35.8 | 26.1 | 50.7 | 55.5 | 35.6 |
| 30-39 | 2157 | 36.5 | 21.0 | 50.1 | 41.9 | 38.3 |
| 40-49 | 2251 | 39.6 | 25.2 | 58.9 | 37.7 | 49.1 |
| 50-59 | 2468 | 40.4 | 29.4 | 69.5 | 40.3 | 59.3 |
| 60-69 | 1712 | 29.8 | 31.8 | 69.1 | 39.2 | 64.3 |
| 70+ | 1013 | 23.0 | 27.6 | 66.4 | 40.0 | 68.1 |
| Total | 11752 | 36.1 | 26.2 | 59.0 | 43.4 | 49.0 |
| Sig.1 | χ2 = 69.07* | χ2 = 45.84* | χ2 = 229.35* | χ2 = 141.36* | χ2 = 431.76* | |
| Female | ||||||
| 20-29 | 2329 | 28.8 | 26.7 | 56.7 | 56.5 | 46.1 |
| 30-39 | 2362 | 29.3 | 25.4 | 55.9 | 47.0 | 53.5 |
| 40-49 | 2368 | 31.4 | 30.9 | 69.4 | 50.0 | 61.0 |
| 50-59 | 2592 | 29.2 | 34.8 | 74.9 | 50.0 | 66.4 |
| 60-69 | 1766 | 21.1 | 37.4 | 68.9 | 49.7 | 65.8 |
| 70+ | 1517 | 20.2 | 23.3 | 64.5 | 35.4 | 69.8 |
| Total | 12934 | 27.9 | 29.4 | 64.4 | 49.4 | 58.6 |
| Sig.1 |
χ2 = 58.69* |
χ2 = 87.67* |
χ2 = 220.92* |
χ2 = 113.49* |
χ2 = 260.20* |
|
| Sig.2 | χ2 = 127.85* | χ2 = 21.77* | χ2 = 52.75* | χ2 = 60.65* | χ2 = 160.15* |
Sig.1: χ2 test, 2 (Each non-pharmacological self-management-Yes or No; Snacking on food and/or beverage, Exercising, Having a bath, Reading or listening to music and Maintaining a regular schedule) × 6 (age effect; 20-29, 30-39, 40-49, 50-59, 60-69, 70+)
Sig.2: χ2 test, 2 (Each non-pharmacological self-management-Yes or No; Snacking on food and/or beverage, Exercising, Having a bath, Reading or listening to music and Maintaining a regular schedule) × 2 (gender effect; male, female)
p<0.001
Logistic Regression Analyses
The results of the logistic regression analyses are shown in Table 3. In Model 1, snacking on food and/or beverages and reading or listening to music showed significant positive associations with EDS. In contrast, having a bath and maintaining a regular schedule showed significant negative associations with EDS. In Models 2-4, reading or listening to music showed no association with EDS, and snacking on food and/or beverages showed a positive association, while having a bath and maintaining a regular schedule showed negative associations with EDS.
Table 3.
Logistic Regression Results for Prediction of Excessive Daytime Sleepiness (EDS) Among the General Adult Population (N = 24,686)
| Model 1 |
Model 2 |
Model 3 |
Model 4 |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Prevalence of EDS (%) | Crude OR | 95% CI | P-value | Adjusted OR | 95% CI | P-value | Adjusted OR | 95% CI | P-value | Adjusted OR | 95% CI | P-value | |
| Snacking on food and/or beverage | |||||||||||||
| No | 2.7 | ||||||||||||
| Yes | 4.0 | 1.50 | 1.26–1.80 | <0.01 | 1.36 | 1.11–1.67 | <0.01 | 1.34 | 1.09–1.65 | 0.01 | 1.42 | 1.15–1.76 | <0.01 |
| Exercising | |||||||||||||
| No | 3.1 | ||||||||||||
| Yes | 3.1 | 1.00 | 0.82–1.21 | 0.96 | 1.08 | 0.86–1.37 | 0.50 | 1.11 | 0.88–1.41 | 0.37 | 1.15 | 0.90–1.45 | 0.26 |
| Having a bath | |||||||||||||
| No | 3.6 | ||||||||||||
| Yes | 2.8 | 0.77 | 0.65–0.92 | <0.01 | 0.76 | 0.61–0.94 | 0.01 | 0.75 | 0.61–0.93 | 0.01 | 0.76 | 0.61–0.95 | 0.01 |
| Reading or listening to music | |||||||||||||
| No | 2.9 | ||||||||||||
| Yes | 3.4 | 1.20 | 1.01–1.42 | 0.04 | 1.17 | 0.95–1.44 | 0.13 | 1.13 | 0.92–1.39 | 0.24 | 1.12 | 0.91–1.38 | 0.28 |
| Maintaining a regular schedule | |||||||||||||
| No | 4.0 | ||||||||||||
| Yes | 2.2 | 0.54 | 0.45–0.64 | <0.01 | 0.62 | 0.51–0.77 | <0.01 | 0.71 | 0.57–0.88 | <0.01 | 0.71 | 0.57–0.88 | <0.01 |
Other Adjustment factors
Model 1: non-adjustment.
Model 2: sex, age, size of community and depression status.
Model 3: sex, age, size of community, depressive status, short sleep duration and subjective insufficient sleep.
Model 4: sex, age, size of community, depressive status, short sleep duration, subjective insufficient sleep, alcohol use and hypnotic medication use.
OR: odds ratio
CI: confidence interval
DISCUSSION
In the present study, we examined the prevalence of nPSM practices to obtain good sleep and the associations between each nPSM practice and EDS. This study was of epidemiological significance in that the participants were randomly selected from a nationwide population and the sample size was large. In effect, the age structure of the participants (shown in Table 1) was very close to that found in the national census, which had been conducted during the same period. This indicates that the study population represents the general population of Japan. To our knowledge, no similar epidemiological study has been reported to date.
Among the nPSM practices examined in this study, the prevalence of having a bath was highest among both men and women, followed by maintaining a regular schedule. In the U.S., Ancoli-Israel et al. found that the prevalence of exercising was highest (75%) among three nPSM practices in subjects without sleep disturbance, followed by reading (9%) and relaxing.9 The survey of Morin et al. of the general population in Canada demonstrated that among reading, receiving acupuncture, getting a massage, relaxing, and listening to music, the prevalence of reading was highest (32.5%), followed by listening to music (25.2%).11 In the present study, exercising and reading were included among the choices of nPSM practices, although the prevalence of exercising (approximately 30%) was the lowest among the 5 practices. Exercising and reading were actively adopted as self-management practices for sleeping by participants in studies conducted outside Japan, and thus the selection of self-management practices for sleep appear to differ across countries. The practice of having a bath, the prevalence of which was the highest in the present study, was not an identified practice in the previous studies outside Japan. This may be attributable to the unique habit of the Japanese taking a nightly hot bath.
In the present study, the prevalence of maintaining a regular schedule increased with age, the highest prevalence being evident among participants in their 70s. This result coincides with those of previous studies conducted in the US.13,14 It is inferred that with age, people tend to become more health conscious and prefer a good sleep at night and lively daytime activities.
In this study, we attempted to classify the examined nPSM practices into favorable and unfavorable types by calculating the odds ratios with regard to EDS. Given our findings, we propose the theory that by employing an nPSM practice showing a statistically and significantly low odds ratio with regard to EDS, a night-sleep problem could be resolved, in turn leading to a decrease in EDS. Moreover, we considered that such a practice would be a favorable one. Conversely, we considered an nPSM practice showing a significantly high odds ratio with regard to EDS could lead to a higher possibility of EDS, and hence would be an unfavorable nPSM. However, there may be cases where a person with a sleep disorder might employ an nPSM practice to prevent EDS, but not benefit from it. In such a scenario, the sleep disorder would be a confounding factor affecting the association between the nPSM practice and EDS. Furthermore, there may be other confounding factors besides sleep. Therefore, in this study, several logistic regression models were set up for inputting various covariates, including sleep duration and subjective sleep insufficiency, to adjust for the possible confounding factors. Despite this attempt, causal relationships can not be thoroughly discussed because this study was cross-sectional; however, since this study was conducted with an authentic, representative sample of the Japanese population, the results obtained may be beneficial for the design of future public health measures for achieving good sleep.
In relation to the above-mentioned theory, the results indicate that having a bath and maintaining a regular schedule are favorable nPSM practices, and that snacking on food and/or beverages is an unfavorable nPSM practice. These results are supported by those of other previous physiological studies. It has been reported that having a bath not only leads to an increase in body temperature, but also stimulates the thermoregulatory center, which promotes the lowering of body temperature and induces slow wave sleep.15,16 Having a bath is also reported to shorten significantly subjective and objective sleep latency and wake time after sleep onset, and increase the duration of slow wave sleep.17–19 A previous study revealed that greater distal vasodilatation, as indicated by the distal-proximal skin temperature gradient, could predict shorter sleep latency in healthy subjects.20 Moreover, Pache et al. have reported that patients with vasospastic syndrome suffer prolonged sleep onset latency due to impaired capacity for distal vasodilation.21,22 Furthermore, it has been reported that subjective sleep sufficiency is better in individuals when they take a bath before going to bed than when they do not.19 Based on the results of these physiological studies, it is inferred that “having a bath” is a favorable nPSM practice that could improve the quality of night sleep and reduce EDS.
Although it is difficult to define maintaining a regular schedule, this practice would include waking up at a regular time in the morning, performing specific activities at specific times, and not staying up late at night. For an individual who has adopted this practice, the sleep-wakefulness rhythm related to daytime activities and rest at night is maintained. In addition to this sleep-wakefulness rhythm, biodynamic rhythms such as autonomic rhythms (including periodic changes in body temperature and blood pressure) and endocrinological rhythms (including the melatonin and cortisol secretory cycles) are maintained in an orderly manner.23 However, when a person's schedule is irregular, these biodynamic rhythms are disrupted, ultimately affecting sleep.13,24–26 Monk et al. reported that the quality of sleep was lower in individuals with irregular schedules than in those with regular schedules.13,24 Manber et al. also reported that subjects who maintained a regular daily rhythm for 4 weeks showed improvement in their night sleep and significant reduction of subjective daytime sleepiness, as compared with controls who had irregular rhythyms.25 The results of these previous studies are in accord with those of the present study, in which the odds ratio of maintaining a regular schedule with regard to EDS was low. Hence, these previous results support our theory that maintaining a regular schedule is a favorable nPSM practice.
In this study, we noted a significantly high odds ratio for snacking on food and/or beverages with regard to EDS, suggesting that it was an unfavorable nPSM practice. A previous epidemiological study reported that irregular eating habits and subjective sleep insufficiency were closely associated,27 and eating before going to bed was reported elsewhere to activate the digestive system and impede the body and brain from preparing to have a good rest; thus, this practice eventually hampered good sleep.28 Therefore, the practice of snacking on food and/or beverages may actually lead to hampered sleep and consequently induce EDS.
The results of the present study provide suggestions on the appropriate self-management practices that should be employed for obtaining good sleep and preventing EDS. Performing such favorable self-management practices is vital for preventing various mental and somatic disorders since sleep disturbance is a risk factor for such disorders. Therefore, the identification of such favorable and unfavorable self-management practices in this study will contribute not only to the prevention of EDS, but also to the planning of public health policies and measures.
This study had a few limitations. First, because the study was cross-sectional, a causal relationship could not be established. A follow-up study will be required to verify the results. Second, excessive sleepiness was evaluated by only one questionnaire item. In our future studies we plan to use epidemiological tools such as the Epworth Sleepiness Scale. Third, all data used were subjective and obtained from a self-administered questionnaire. Because we preferred data accumulation from a larger number of participants nationwide, physiological measurements could not be obtained. However, several studies have reported that self-reported data on sleeping habits coincide with physiological data to a certain extent.29,30 Fourth, due to the limitation of space on our self-administered questionnaire, we could not adopt the social demographic items of confounding factors such as marital status, education, occupation, and income, and these remain the subject for further study.
To conclude, having a bath and maintaining a regular schedule appear to be favorable nPSM practices for obtaining good sleep, while snacking on food and/or beverages is an unfavorable practice, findings which can contribute to the planning of public health measures with respect to sleep.
DISCLOSURE STATEMENT
This was not an industry supported study. The authors have indicated no financial conflicts of interest.
ACKNOWLEDGMENT
This study was supported by a Health Science Research Grant from the Ministry of Health, Labor and Welfare of the Japanese Government (H20-JUNKANKITOU-IPPAN-002).
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