Elsevier

Sleep Medicine

Volume 14, Issue 2, February 2013, Pages 206-210
Sleep Medicine

Original Article
Association between sleep duration, weight gain, and obesity for long period

https://doi.org/10.1016/j.sleep.2012.09.024Get rights and content

Abstract

Background

Although previous studies showed the long-term effects of sleep duration on risk of weight gain, Western tends to gain weight irrespective of sleep duration over a long period. Conversely, it is showed that body mass index (BMI) decreases during a long period in Japanese and thus, the long-term effect of sleep duration on weight gain and obesity is still unclear in Asia.

Methods

We followed up 13,629 participants aged 40–79 years and prospectively collected data from 1995 to 2006. We divided the participants into five groups according to their self-reported sleep duration: ⩽5 h (short sleep), 6 h, 7 h (reference), 8 h, and ⩾9 h (long sleep). The main outcome was ⩾5 kg weight gain or BMI  25 kg/m2 (obesity). We used logistic regression analyses to derive odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for several confounding factors.

Results

We observed no association between sleep duration and risk of ⩾5 kg weight gain and obesity. After stratification by BMI, long sleepers had a significantly increased risk of ⩾5 kg weight gain (OR: 1.36, 95%CI: 1.09–1.70) in obese participants.

Conclusions

Among community-dwelling Japanese, only obese long sleepers have a significantly increased long-term risk of ⩾5 kg weight gain.

Introduction

Obesity is increasing worldwide and its associated health problems are now widely recognized. According to the World Health Organization, Asia has a low prevalence of obesity in comparison to other areas of the world [1]. They recommended that obesity should be defined lower in Asia than Western [2]. In Japan, the prevalence of obesity is only 3%, and severe obesity almost never exists [3]. However, the percentage of body fat is higher in Asian than in Western with the same body mass index (BMI) [4]. Meanwhile, according to the Organisation for Economic Co-operation and Development, Koreans have the shortest mean sleep duration in the world, followed by the Japanese [5].

The associations between sleep duration, weight gain, and/or obesity have been examined previously in seven meta-analyses and a systematic review [6], [7], [8], [9], [10], [11], [12]. However, almost all of the populations studied were Western, with longer mean sleep durations and higher prevalence of obesity than Asian populations. In Asia, three prospective studies, all from Japan, have examined the association between sleep duration and obesity [13], [14], [15]. However, the study participants were recruited from among people who were undergoing health checkups. The effect of sleep duration on weight gain and obesity has not yet been examined in an Asian population or recruited from the general community.

In addition, some previous studies have examined the long-term effects of sleep duration on weight gain and obesity from data accumulated over periods of at least 10 years [16], [17]. Even though these studies showed that short sleepers were at risk of weight gain and obesity, Patel et al. showed that their study participants gained weight irrespective of sleep duration over a 16 year period [16]. In contrast, Matsushita et al. showed that mean BMI tended to decrease during a 10 year follow-up period in Japanese participants aged ⩾50 years [18]. Thus, the long-term association between sleep duration, weight gain, and obesity might differ between Western and Japanese populations, and the long-term effect of sleep duration on weight gain and obesity is still unclear in Asia.

In the present study, therefore, we examined the long-term association between sleep duration, weight gain, and obesity in Japanese subjects recruited from the general community based on data accumulated over 12 years.

Section snippets

Study cohort

Between October and December 1994, we distributed a self-administered questionnaire survey of various lifestyle habits to all National Health Insurance (NHI) beneficiaries aged 40–79 years who lived in the catchment area of Ohsaki Public Health Center, Miyagi Prefecture, northeastern Japan [19]. Among 54,996 eligible individuals, 52,029 (95%) responded. We followed-up with the participants from January 1, 1995 through December 31, 2008 and recorded any mortality or migration by reviewing the NHI

Baseline characteristics in terms of sleep duration categories

Table 1 shows the baseline characteristics of the study participants according to the categories of sleep duration.

The mean age was highest in the long sleep category. The proportions of women decreased linearly as the sleep duration category increased. Even though the mean weight was the lowest in the short sleep category, the mean BMI showed no significant difference. The mean weight change increased linearly as the sleep duration category increased. The proportion of participants who were

Discussion

The present results indicate that the association between sleep duration, ⩾5 kg weight gain and obesity showed no significant association over a long period in Japanese subjects recruited from the community. After stratification by BMI, obese long sleepers showed a significantly increased risk of ⩾5 kg weight gain (OR: 1.36, 95%CI: 1.09–1.70).

The mean age in the long sleep category was oldest and the proportion of women in the short sleep category was highest in the sleep duration categories, but

Conflict of Interest

This was not an industry supported study. The authors declare that they have no conflicts of interest.

The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2012.09.024.

. ICMJE Form for Disclosure of Potential Conflicts of Interest form.

Acknowledgments

This study was supported by a Health Sciences Research Grant for Health Services (H22-Junkankitou (Seisyu)-Ippan-012, H23-Junkankitou (Seisyu)-Ippan-005, H23-Junkankitou (Seisyu)-Wakate-015), Ministry of Health, Labour and Welfare, Japan. Masato Nagai is a recipient of a Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists.

References (28)

  • J. Horne

    Obesity and short sleep: unlikely bedfellows?

    Obes Rev

    (2011)
  • L.S. Nielsen et al.

    Short sleep duration as a possible cause of obesity: critical analysis of the epidemiological evidence

    Obes Rev

    (2011)
  • S.R. Patel

    Reduced sleep as an obesity risk factor

    Obes Rev

    (2009)
  • S.R. Patel et al.

    Short sleep duration and weight gain: a systematic review

    Obesity (Silver Spring)

    (2008)
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