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

Sleep features and the risk of type 2 diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

This study aimed to assess the associations between multidimensional sleep features and type 2 diabetes mellitus (T2DM).

METHODS

We conducted a systematic search across the PubMed, Embase, Web of Science, and Scopus databases for observational studies examining the association between nighttime sleep duration, nighttime sleep quality, sleep chronotype, and daytime napping with type 2 diabetes mellitus (T2DM), up to October 1, 2024. If I2 < 50%, a combined analysis was performed based on a fixed-effects model, and vice versa, using a random-effects model.

RESULTS

Our analysis revealed that a nighttime sleep duration of less than 7 h (odds ratio [OR] = 1.18; 95% CI = 1.13, 1.23) or more than 8 h (OR = 1.13; 95% CI = 1.09, 1.18) significantly increased the risk of T2DM. Additionally, poor sleep quality (OR = 1.50; 95% CI = 1.30, 1.72) and evening chronotype (OR = 1.59; 95% CI = 1.18, 2.13) were associated with a notably greater risk of developing T2DM. Daytime napping lasting more than 30 min augments the risk of T2DM by 7-20%. Interactively, the incidence of T2DM was most significantly elevated among individuals with poor sleep quality and nighttime sleep duration of more than 8 h (OR = 2.15; 95% CI = 1.19, 3.91).

CONCLUSIONS

A U-shaped relationship was observed between sleep duration and type 2 diabetes mellitus (T2DM), with the lowest risk occurring at a sleep duration of 7 to 8 h. Additionally, poor sleep quality, evening chronotypes, and daytime napping exceeding 30 min emerged as potential risk factors for T2DM. These high-risk sleep characteristics interacted with one another, amplifying the overall risk of developing the disease.

Association between sleep behaviors and adiposity indices among U.S. adults: a cross-sectional study

Objectives

This study aimed to clarify the relationship between sleep behaviors and adiposity indices.

Methods

We analyzed NHANES data from 2011 to 2018 for adults aged 20-80, assessing BMI, waist circumference (WC), lean mass, and body fat percentage with DEXA scans and physical measurements. Sleep duration was categorized into short (<7 h), normal (7-9 h), and long (>9 h), as well as their sleep status based on questionnaires. Furthermore, we examined the interaction effects between sleep duration and sleep patterns.

Results

Among 19,951 participants providing BMI and WC data, and 10,716 for lean mass and body fat percentage, short sleep duration correlated with higher BMI (β = 0.56, 95% CI: 0.36-0.76), WC (β = 0.90, 95% CI: 0.43-1.37), and lean mass (β = 0.70, 95% CI: 0.32-1.07). Individuals with sleep disorders showed increased values across all indices: BMI (β = 0.93, 95% CI: 0.72-1.13), WC (β = 2.40, 95% CI: 1.92-2.88), lean mass (β = 0.71, 95% CI: 0.30-1.12), and body fat percentage (β = 0.64, 95% CI: 0.37-0.90). No significant interaction effects were found between sleep duration and sleep disorders.

Conclusion

Our findings indicate that individuals with short sleep duration and sleep disorders are likely to carry a higher weight burden, indicating potential targets for addressing obesity-related health issues.

Findings and Methodological Shortcomings of Investigations Concerning the Relationship Between Sleep Duration and Blood Pressure: A Comprehensive Narrative Review

Cardiology and sleep societies recommend 7-9 h sleep/night for adults (7-8 h for seniors) and more for youngsters; nonetheless, short sleep duration (SSD) of <7 h/night is epidemic. We searched PubMed for representative investigations, including those cited by meta-analyses, that reported association between SSD and long sleep duration (LSD) of >9 h/night and blood pressure (BP) levels to assess shortcomings of their methods. Studies indicate both SSD and LSD negatively impact BP despite major deficiencies, such as (i) reliance mainly on cross-sectional rather than longitudinal protocols, (ii) inclusion of participants diagnosed with hypertension (HTN) and/or taking antihypertension medications, (iii) assessment of BP and diagnosis of HTN performed by single wake-time office measurement rather than multiple measurements performed by 24 h ambulatory BP monitoring (ABPM), and (iv) determination of SD by subjective recall, single-night polysomnography, or diary recordings rather than objective wrist actigraphy of sufficient duration. The limited number of ABPM-based studies, despite evidencing major shortcomings, particularly (i) assessment for 24 h rather than preferred ≥48 h and (ii) inclusion of subjects diagnosed with HTN and/or taking antihypertension medications, also report association between abnormal SD and elevated 24 h 'daytime'/wake-time diastolic and systolic (SBP) means plus 'nighttime'/sleep-time SBP mean and dipping-the latter two indices, in combination, the strongest predictors of major adverse cardiovascular events.

Sex differences in the association between short sleep duration and obesity: A systematic-review and meta-analysis

AIMS

Obesity is a leading contributor to global morbidity and mortality. Short sleep duration is significantly associated with the incidence of obesity, however, it remains unclear whether this relationship is influenced by sex. The purpose of this meta-analysis was to systematically evaluate the evidence of whether the association between short sleep duration and obesity differs between males and females.

DATA SYNTHESIS

The protocol was registered with PROSPERO (CRD42023374205). From inception through June 2023, Medline, Embase and Web of Science databases were searched for longitudinal cohort studies with minimum 12 months of observation. The quality of studies was assessed using the Newcastle-Ottawa Quality Assessment for Cohort Studies. Results were pooled using a random effects model. Results are expressed as ratio of odds ratios (ROR) with 95% confidence interval (CI). ROR directly estimates the relative strength of the association of interest (measured as odds ratio [OR] between females and males). Sensitivity analysis was performed and inconsistency between studies was assessed using I2 statistics. A total of 4582 articles were retrieved with the search strategy, of which 6 were included. The meta-analysis indicated that the association between short sleep duration and obesity incidence was statistically significant in both men [OR 1.26 (95% CI 1.13-1.40)] and women [OR 1.36 (95% CI 1.16-1.59)]. However, it did not differ significantly between sexes ROR (women/men) 1.04 (95%CI 0.79-1.36; I2 20.1%).

CONCLUSIONS

This meta-analysis indicates that women and men who subjectively report short sleep duration have similarly increased risks of incident obesity.

Association of sleep duration with Visceral Adiposity Index: a cross-sectional study based on the NHANES 2007-2018

OBJECTIVE

We aimed to assess the associations between sleep duration and Visceral Adiposity Index (VAI).

DESIGN

Cross-sectional study.

SETTING

The National Health and Nutrition Examination Survey (2007-2018).

PARTICIPANTS

A total 11 252 eligible participants who have complete information for sleep duration and VAI.

OUTCOME MEASURE

The VAI index, which is sex-specific and takes into consideration factors such as waist circumference, body mass index, high-density lipoprotein cholesterol and triglycerides, was calculated in accordance with prior research. Multiple linear regressions and subgroup analyses were employed to evaluate the connection between the duration of sleep and the VAI.

RESULTS

The mean sleep duration and VAI of included participants were 7.05 hours/day and 2.03, respectively. After adjusting for the sociodemographic, lifestyle and other covariates, short sleep was significantly linked to increased VAI (β=0.15, 95% CI 0.01 to 0.28) in relation to middle sleep duration, whereas no significant association was found between long sleep duration and VAI. An L-shaped relationship was observed between sleep duration and VAI. When sleep duration was less than 7.5 hours/day, a negative association between sleep duration and VAI was obvious. However, when sleep duration was >7.5 hours/day, VAI was increased with a longer sleep duration, although it was not significant.

CONCLUSIONS

An L-shaped relationship was observed between sleep duration and VAI, with insufficient sleep, being independently linked to a higher VAI. This implies that sleep deprivation might be associated with visceral adipose distribution and disfunction.

Relationship of trihalomethane in drinking water with hypertension and arrhythmia among young and middle-aged adults in Petropavlovsk, Kazakhstan

There are no studies investigating the association of chlorinated drinking water with the risk of cardiovascular diseases (CVDs) among young and middle-aged adults. This study was aimed to assess the associations between trihalomethanes (THMs) in drinking water and the risk of CVDs in in the target group in Petropavlovsk, Kazakhstan. 448 dwellers of Petropavlovsk were asked about their demographic, socioeconomic, lifestyle, behavioural characteristics, and drinking water preferences. THMs exposure was assessed to each participant based on their residence address. We used multivariable logistic regression analysis to assess the risk of CVDs in young and middle-aged adults. The results showed that the risk of hypertension in the adjusted logistic regression model was increased by 68%   and a 2.7-fold   in the second and third THM tertiles, respectively. Participants in the second and third THM exposure tertiles had a 2.3-fold and a 4.8-fold increase in the risk of arrhythmia.

A systematic review of evidence on employment transitions and weight change by gender in ageing populations

Background

Becoming unemployed is associated with poorer health, including weight gain. Middle- and older-age adults are a growing segment of workforces globally, but they are also more vulnerable to changes to employment status, especially during economic shocks. Expected workforce exits over the next decade may exacerbate both the obesity epidemic and the economic burden of obesity. This review extends current knowledge on economic correlates of health to assess whether employment transitions impact body weight by sex/gender among middle-aged and older adults.

Methods

Eight bibliometric databases were searched between June and July 2021, supplemented by hand-searches, with no restriction on publication date or country. Longitudinal studies, or reviews, were eligible when examining body weight as a function of employment status change in adults ≥50 years. Data extraction and quality appraisal used predefined criteria; reported findings were analysed by narrative synthesis.

Results

We screened 6,001 unique abstracts and identified 12 articles that met inclusion criteria. All studies examined retirement; of which two also examined job-loss. Overall, studies showed that retirement led to weight gain or no difference in weight change compared to non-retirees; however, reported effects were not consistent for either women or men across studies or for both women and men within a study. Reported effects also differed by occupation: weight gain was more commonly observed among retirees from physical occupations but not among retirees from sedentary occupations. Few studies assessed the role of health behaviours; sleep was the least studied. Most studies were medium quality.

Conclusions

Existing studies do not provide a clear enough picture of how employment transitions affect body weight. Firm conclusions on the impact of employment transitions on weight cannot be made without further high-quality evidence that considers the role of gender, job-type, other health behaviours, and other transitions, like job-loss.

Relationship of night sleep duration with health lifestyle, depressive symptoms, internet addiction in Chinese High school Students

This study aimed to explore effects of night sleep duration and its relationships with health lifestyle, depressive symptoms and Internet addiction among high school students. In this study, we used multistage stratified random cluster sampling method. A total of 2149 adolescents aged 14-18 years old were recruited in the study. Associations among sleep duration and demographic characteristics, health lifestyle, depressive symptoms and Internet addiction among Chinese students were analyzed by univariate analysis and binary logistic regression analysis. Then, the structural equation model (SEM) was used to study the relationships between sleep duration and other variables. The mean sleep duration was (6.56 ± 1.15) hours. Approximately 16.0% of all participants had short sleep duration, and 20.5% had long sleep duration. Binary logistic regression analysis revealed that having more high sugar drinks and fried foods were positively associated with short sleep duration. Depressive symptoms not only directly had a negatively impact on sleep duration, but also had an indirect effect on sleep duration through Internet addiction. Sleep problems are common within the population of adolescents. Depressive symptoms was an important factor in the prevention of abnormal sleep duration, and interventions that target Internet addiction is key to reduce inadequate sleep.

Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity

BACKGROUND

Although the consequences of sleep deficiency for obesity risk are increasingly apparent, experimental evidence is limited and there are no studies on body fat distribution.

OBJECTIVES

The purpose of this study was to investigate the effects of experimentally-induced sleep curtailment in the setting of free access to food on energy intake, energy expenditure, and regional body composition.

METHODS

Twelve healthy, nonobese individuals (9 males, age range 19 to 39 years) completed a randomized, controlled, crossover, 21-day inpatient study comprising 4 days of acclimation, 14 days of experimental sleep restriction (4 hour sleep opportunity) or control sleep (9 hour sleep opportunity), and a 3-day recovery segment. Repeated measures of energy intake, energy expenditure, body weight, body composition, fat distribution and circulating biomarkers were acquired.

RESULTS

With sleep restriction vs control, participants consumed more calories (P = 0.015), increasing protein (P = 0.050) and fat intake (P = 0.046). Energy expenditure was unchanged (all P > 0.16). Participants gained significantly more weight when exposed to experimental sleep restriction than during control sleep (P = 0.008). While changes in total body fat did not differ between conditions (P = 0.710), total abdominal fat increased only during sleep restriction (P = 0.011), with significant increases evident in both subcutaneous and visceral abdominal fat depots (P = 0.047 and P = 0.042, respectively).

CONCLUSIONS

Sleep restriction combined with ad libitum food promotes excess energy intake without varying energy expenditure. Weight gain and particularly central accumulation of fat indicate that sleep loss predisposes to abdominal visceral obesity. (Sleep Restriction and Obesity; NCT01580761).

Assessment of sex differences in associations between sleep duration and lipid/glucose metabolism in urban Japan: a cross-sectional study

Inadequate sleep durations (short or long) are related to worsening of lipid/glucose metabolism, leading to atherosclerotic cardiovascular diseases (ASCVD). Few data exist on sex differences in this relationship that, to date, has been scarcely reported. This cross-sectional study included 6678 men and 4700 women at the Health Planning Center of Nihon University Hospital, located in the center of Tokyo, between September 2015 and October 2016. The prevalence of diabetes and dyslipidemia in the participants was 3.3% and 6.5%, respectively. Sleep duration was divided into five categories: < 5 h, 5-6 h, 6-7 h, 7-8 h, and ≥ 8 h. We examined the odds ratio (OR) and 95% confidence interval (CI) of lipid/glucose metabolism-related markers for the reference value defined in each guideline with 6-7 h as the reference of comparison. In men, a sleep duration of < 5 h was associated with ORs of 1.32 and 1.33 (95% CI, 1.01-1.73 and 1.02-1.74) for LDL-C level ≥ 120 mg/dL and non-HDL-C level of ≥ 150 mg/dL (defined as "borderline hyper" by the Japan Atherosclerosis Society Guidelines for Prevention of ASCVD 2017), respectively. Moreover, a sleep duration of < 5 h was associated with an OR of 1.77 (1.33-2.35) for fasting blood glucose of ≥ 100 mg/dL (defined as "high" by a specialized lifestyle checkup program in Japan). In women, sleep duration of < 5 h was associated with an OR of 1.70 (1.24-2.33) for HbA1c level of ≥ 5.6% (defined as "high" by a specialized life style checkup program in Japan). However, there was no association between sleep duration and serum lipid profile. Inadequate short sleep duration was as a potential risk factor of adverse lipid and/or glucose metabolism in both sexes. However, there were sex differences in associations between sleep duration and lipid/glucose metabolism in urban Japan. To further reduce risks of ASCVD, it is of particular importance to emphasize adequate sleep duration in both sexes.Trial registration UMIN ( http://www.umin.ac.jp/ ) Study ID: UMIN000037643 retrospectively registered on August 9, 2019.

Prevalence and correlates of total sleep time among the older adults during COVID-19 pandemic in Bangladesh

Purpose

The present study was aimed to identify inappropriate sleep duration and its correlates among the Bangladeshi older adults during the COVID-19 pandemic.

Material and methods

This cross-sectional study was carried out among 1030 older adults aged 60 years and above in Bangladesh. Information was collected through telephone interviews using a pretested semi-structures questionnaire installed in SurveyCTO mobile app. Sleep duration was defined as total sleep time (TST) in last 24 h including day and nighttime sleep. TST was further categorized into shorter (<7 h), recommended (7-8 h), and longer sleep (>8 h) according to 2015 National Sleep Foundation guideline. The multinomial logistic regression model identified the factors associated with sleep duration.

Results

Mean TST was 7.9 h (SD=1.62). Of the total participants, 28.2% had longer and 17.8% shorter sleep duration. In the regression model, participants' age of ≥80 years (OR: 3.36, 1.46-7.73), monthly family income of <5,000 Bangladeshi Taka (OR: 3.50, 1.79-6.82), difficulty in getting medicine during COVID-19 (OR: 1.72, 1.05-2.82), lack of communication during the pandemic (OR: 2.20, 1.43-3.40) and receiving COVID-19 related information from friends/family/neighbours (OR: 1.83, 1.11-3.01) were significantly associated with shorter TST. On the other hand, monthly family income of < 5,000 Bangladeshi Taka (OR: 2.00, 1.13-3.53), difficulty in getting medicine during COVID-19 pandemic (OR: 2.01, 1.33-3.03) and receiving COVID-19 related information from radio/TV (OR: 2.09, 1.22-3.59) were associated with longer TST.

Conclusions

The study findings suggest implementing sleep management program for older adults in Bangladesh, particularly during emergencies like COVID-19.

Is self-reported short sleep duration associated with obesity? A systematic review and meta-analysis of cohort studies

CONTEXT

A possible association between self-reported short sleep duration and risk of obesity has been studied.

OBJECTIVE

To analyze the association between sleep duration and obesity.

METHODS

The LILACS, Medline, Central, Embase, and OpenGrey databases were searched from inception until July 2020. Two authors screened the studies independently according to the PECO strategy, as follows: participants: > 18 years old; exposure: short sleep duration; control: regular sleep; outcome: obesity). Only cohort studies were included. A total of 3286 studies were retrieved with the search strategy, but only 36 were included. Disagreements were resolved by a third author. The quality of studies was assessed with Newcastle-Ottawa Quality Assessment Form for Cohort Studies. The certainty of the evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

Thirty-six studies were included, and 22 contributed quantitative data. Most of the studies (n = 27) assessed sleep by self-report. The meta-analysis showed a significant association between self-reported short sleep and development of obesity, and the chances of developing obesity increased when self-reported sleep duration decreased.

CONCLUSIONS

Self-reported short sleep was significantly associated with a higher incidence of obesity, with moderate quality of evidence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42019130143.

Sleep problems and their association with weight and waist gain - The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

OBJECTIVE

To evaluate the association of sleep problems with weight and waist size gain during four years of follow-up.

METHODS

We investigated 13,030 participants (35-74 years) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a multicentric cohort conducted with civil servants from six academic institutions recruited between 2008 and 2010. Sleep problems were assessed at baseline by the Clinical Interview Schedule - Revised (CIS-R), designed to detect common mental disorders based on somatic, depressive and anxiety symptoms. Weight and waist size were measured at baseline and at follow-up (2012-2014). Large weight and waist size gain were defined as ≥ 90th percentile (≥1.65 kg/year and ≥2.41 cm/year, respectively).

RESULTS

Sleep problems were associated with higher risk of a large weight gain (RR = 1.11; 95% CI 1.01-1.24) and large waist size gain (RR = 1.19; 95% CI 1.07-1.32), adjusted for age, sex, ethnicity, income, educational level, investigation center, smoking, alcohol intake, dietary energy intake, leisure-time physical activity and body mass index (BMI) or waist circumference at baseline. After additional adjustment for common mental disorders the associations became non-significant (RR = 0.99; 95% CI 0.88-1.12; RR = 1.08; 95% CI 0.97-1.22, respectively).

CONCLUSION

Sleep problems are associated with increased risk of developing large weight and waist size gain, but are not independently associated with common mental disorders.

EVIDENCE OF THE ASSOCIATION BETWEEN SLEEP DURATION AND BLOOD PRESSURE IN ADOLESCENTS: A SYSTEMATIC REVIEW

OBJECTIVE

To review the epidemiological evidence of the association between sleep duration and blood pressure in adolescents.

DATA SOURCES

We performed a systematic review of observational studies in Medline, Scopus, Lilacs, Web of Science, Science Direct databases and Virtual Libraries in English, Spanish and Portuguese published until September 2018. Studies were selected first by title and abstract, then by complete reading, according to the eligibility criteria. The reference list of selected articles was evaluated in order to retrieve relevant studies.

DATA SYNTHESIS

Initially, 1,455 articles were retrieved. After exclusion due to duplicity or not meeting the eligibility criteria, 13 articles were included in the review. Studies varied greatly in sample size (143 to 6,940 patients), methods of measuring blood pressure and sleep duration, cutoff points, categorization and adjustment of variables. The main evidence from the studies is that short sleep duration is associated with high blood pressure in adolescence, although the presence of association between high blood pressure and long sleep duration is possible, but not clear in the literature.

CONCLUSIONS

Sleep duration, especially short duration, is associated with high blood pressure in adolescents. Such evidence draws attention to implications on cardiovascular health in this age group.

Association between sleep duration and differences between weekday and weekend sleep with body mass index & waist circumference among Black women in Sistertalk II

OBJECTIVES

Examine associations between sleep duration and differences between weekday and weekend sleep with body mass index and waist circumference in a sample of high-risk Black women from the SisterTalk II study.

DESIGN

Cross-sectional analysis of baseline data from an intervention study targeting dietary and physical activity behaviors.

SETTING

Women were recruited from the Providence, RI, USA, area.

PARTICIPANTS

The sample includes 569 middle-aged Black women who were hypertensive or at risk for hypertension.

MEASUREMENTS

Participants self-reported their weekday and weekend sleep duration. Body mass index (BMI) and waist circumference (WC) were objectively measured. Associations between the sleep and anthropometric measures were examined using analysis of variance and multivariable regression models controlling for birthplace, educational attainment, employment status, and annual household income.

RESULTS

25.5% of the sample were very short sleepers (≤6 hrs), 28.8% short sleepers (≥6 to <7 hrs), 40.4% recommended sleepers (≥7 to ≤9 hrs), and 5.3% long sleepers (>9 hrs); 70.7% had a consistent sleep duration (≤2-hour difference between weekday and weekend sleep duration), 21.6% were classified as "weekend snoozers" (>2-hours more sleep on weekends), and 7.7% were classified as "weekend warriors" (>2-hours less sleep on weekends). Compared to recommended sleepers, very short sleepers and long sleepers had significantly greater BMIs, while long sleepers had significantly larger WCs. Being a weekend snoozer was also associated with increased BMI and WC.

CONCLUSIONS

In this sample of high-risk Black women, sleep duration and differences between weekday and weekend sleep were independently associated with excess weight and abdominal obesity.

Sleep duration and obesity in adulthood: An updated systematic review and meta-analysis

Short and long sleep duration have been associated with risk of obesity in children and adolescents. Evidence in adults is more mixed, with biological and psychosocial factors underlying these relationships mostly unknown. This review aimed at qualitatively and quantitatively summarizing previous studies on sleep duration as a predictor of obesity in adults in order to provide an update of the state of art in this field and clarify these relationships. Odds ratios at 95% Confidence Intervals (CI) were estimated using random-effects models. Heterogeneity of effects distribution and publication bias were tested. Twelve articles were selected for short sleep (n = 154,936) and eight for long sleep duration (n = 152,192). Results indicated that short sleep duration (OR: 1.412; 95% CI: 1.177-1.694) was significantly associated with the risk of future obesity, and that long sleep duration (OR: 0.995; 95% CI: 0.889-1.114) was not associated. Heterogeneity was high and lowered to non-significant values when considering gender and extremes of short/long sleep duration. Results seem to confirm a potential role of short sleep duration in predicting but results on long sleep are still mixed. Future investigations on potential mediators of such relationships are needed.

Association of Sleep Duration and Overweight/Obesity among Children in China

To investigate the association of sleep duration with overweight and obesity among children aged 6 to 17 years in China, 2010–2012 data from the China National Nutrition and Health Surveillance (CNHHS) were analyzed. A total of 35,414 children were recruited in the survey. Body mass index (BMI) was converted into three categories: normal weight, overweight and obesity. In multinomial logistic regression model, sleep duration was divided into four groups: very short, short, recommended and long. In restricted cubic splines (RCS), sleep duration was examined as a continuous variable in relation to overweight and obesity. In the very short and short groups, sleep duration was a risk factor for obesity after adjusting for the potential impacts of age, gender, residence, family income, leisure sedentary behavior (SB) and leisure exercise, with OR (Odds Ratio) = 3.01 (95% CI (confidence interval): 2.19–4.15) and OR = 1.24 (95% CI: 1.14–1.35), respectively. The adjusted OR of overweight for short sleep duration relative to a recommended sleep duration was 1.17(95% CI: 1.09–1.26). No significant associations of very short sleep with overweight, of long sleep duration with overweight and obesity were found. The RCS curves between sleep duration and overweight and obesity were both inverted J-shaped. To conclude, the shorter the sleep duration, the higher the risk of overweight and obesity in children. Increasing sleep duration would have a positive effect on reducing overweight and obesity rates in Chinese children.

Association of Sleep Duration and Blood Pressure in Adolescents: A Multicenter Study

BACKGROUND

Evidence suggests that sleep duration is related to blood pressure (BP), but the findings are still inconsistent for adolescents.

OBJECTIVE

To analyze the association between sleep duration and BP in Brazilian adolescents between 12 and 17 years of age.

METHODS

This study is part of the Study of Cardiovascular Risk in Adolescents (ERICA), a multicenter, school-based, cross-sectional study in 273 municipalities in Brazil. The sample consisted of 65,643 adolescents. Sleep duration was measured by a subjective method, and BP was measured by the oscillometric method. Multiple linear regression analyses were performed to evaluate the association between sleep duration and BP.

RESULTS

The mean sleep duration was 8.14 hours (± 1.40), with significant difference between the groups according to BP levels (P < 0.0001). The mean systolic and diastolic BP were 110.59 (± 11.87) and 65.85 (± 7.94) mm Hg, respectively, in the group of adolescents. Sleep duration was significantly associated with BP. Each increase 1 hour in sleep was associated with BP reduction in both sexes combined (P < 0.0001). Considering the effects of covariates, each increase 1 hour in sleep was associated with systolic BP (SBP) reduction among boys (P = 0.004) and SBP elevation among girls (P = 0.009), after full adjustment.

CONCLUSION

The results suggest that each increase in sleep duration was associated with SBP elevation among girls. Such findings may have important implications for cardiovascular health in adolescence.

Demographic, Socio-economic and Lifestyle Determinants of Under- and Over-nutrition among Bangladeshi Adult Population: Results from a Large Cross-Sectional Study

Bangladesh is currently going through a nutritional transition with rapid increase in overnutrition while undernutrition is still remaining prevalent. Nevertheless, population-based data on demographic, socio-economic and lifestyle factors associated with underweight and overweight among adult population is scarce. Employing a nationwide cross-sectional survey, we collected anthropometric, demographic, socio-economic, lifestyle and dietary information from 12,180 adults aged ≥35 years. Body Mass Index (BMI) was calculated using standard formula and categorized into underweight (<18.50), normal weight (18.50–22.99), and overweight (≥23.00). Multivariable multinomial logistic regression was performed to identify factors associated with underweight and overweight. Overall, prevalence of underweight and overweight was 18.1% (95% CI: 17.5–18.8) and 33.7% (95% CI: 32.9–34.6), respectively. All the demographic, socio-economic, dietary and lifestyle factors showed significant association with nutritional status in bivariate analysis. In adjusted analysis, factors showing significant positive association with underweight included female gender (ARRR-1.38, 95% CI: 1.11–1.71), older age [compared to 35–39 years age group, ARRR (95% CI) for ≥ 70 years is 2.32 (1.89–2.86), for 60–69 years is 1.62 (1.36–1.93), for 50–59 years 1.34 (1.13–1.58) and for 40–49 years 1.05 (0.87–1.15)] and smoking habit (ARRR-1.32, 95% CI: 1.14–1.52) while factors showing significant inverse association with underweight included higher household wealth [compared to lowest wealth quintile, ARRR (95% CI) for highest quintile is 0.68 (0.55–0.84), for second highest quintile 0.77 (0.65–0.91), for middle quintile 0.81 (0.69–0.94) and for second lowest quintile 0.89 (0.77–1.03)], urban residence (ARRR-0.66, 95% CI: 0.66–0.90), and more frequent meat/fish and fruits consumption (ARRR-0.76, 95% CI: 0.65–0.90). On the other hand, factors significantly associated with increased risk of overweight included female gender (ARRR-1.35, 95% CI: 1.12–1.63), higher household wealth [compared to lowest wealth quintile, ARRR (95% CI) for highest quintile is 2.27 (1.93–2.68), for second highest quintile 1.67 (1.44–1.94), for middle quintile 1.26 (1.10–1.46) and for second lowest quintile 1.07 (0.93–1.24), excess food availability [compared to food shortage, ARRR (95% CI) for excess food in the household is 1.29 (1.12–1.47) and for no shortage/no excess is 1.23 (1.09–1.38) and more frequent fruits consumption [compared to no fruits, ARRR (95% CI) for 5–7 days per week consumption is 1.61 (1.41–1.83) and for 3–4 days per week is 1.28 (1.16–1.41) and factors significantly associated with decreased risk of overweight included older age [compared to 35–39 years age group, ARRR (95% CI) for ≥ 70 years is 0.77 (0.64–0.93), for 60–69 years is 0.82 (0.71–0.94), for 50–59 years 0.91 (0.80–1.04) and for 40–49 years 1.01 (0.89–1.15)] and smoking (ARRR-0.76, 95% CI: 0.68–0.86). Both underweight and overweight are prevalent in Bangladeshi adult population. Several demographic, socio-economic, dietary and lifestyle factors are associated with underweight and overweight in Bangladesh. Population level impact of these factors should be examined to design suitable public health and nutrition interventions to address this dual challenge.

Long sleep duration predicts a higher risk of obesity in adults: a meta-analysis of prospective cohort studies

BACKGROUND

The connections between long sleep duration and obesity or weight gain warrant further examination. This meta-analysis aimed to evaluate whether long sleep duration was associated with the risk of obesity, weight gain, body mass index (BMI) change or weight change in adults.

METHODS

PubMed, Embase, Cochrane Library, Elsevier Science Direct, Science Online, MEDLINE and CINAHL were searched for English articles published before May 2017. A total of 16 cohort studies (n = 329 888 participants) from 8 countries were included in the analysis. Pooled relative risks (RR) or regression coefficients (β) with 95% confidence intervals (CI) were estimated. Heterogeneity and publication bias were tested, and sensitivity analysis was also performed.

RESULTS

We found that long sleep duration was associated with higher risk of obesity (RR [95% CI] = 1.04 [1.00-1.09], P = 0.037), but had no significant associations with weight gain, BMI change or weight change. Long sleep duration increased the risk of weight gain in three situations: among men, in studies with <5 years follow-up, and when sleep duration was 9 or more hours.

CONCLUSIONS

Long sleep duration was associated with risk of obesity in adults. More cohort studies with objective measures are needed to confirm this relationship.

Social-biological influences on sleep duration among adult residents of Northeastern China

Background

Cold climates traditionally have conferred long sleep duration in the residents in northeast China; however, modern lifestyle reduces sleep duration. In this study, we investigated social-biological factors influencing sleep duration in the adult residents in northeast China.

Methods

This study was performed using data from the Investigation of Chronic Disease Morbidity Rate and Risk Factors of Adults in Jilin Province, China. Associations between sleep duration and indices of demographic characteristics, health-related behaviors, and disease history in adult residents were analyzed using univariate analysis and multivariate logistic regression analysis.

Results

The mean sleep duration was 7.24 h. Of the 21,435 participants, approximately 53.4% had short sleep duration (sleep duration per day < 7 h), and 10.5% had long sleep duration (sleep duration per day > 9 h). There were associations between short sleep duration and indices, including age, place of residence, marital status, educational level, alcohol drinking, dietary, obesity, and history of coronary heart disease (CHD) or myocardial infarction (MI). There existed associations of long sleep duration with indices, such as age, place of residence, occupation, educational level, average monthly earnings, and physical exercise.

Conclusion

Short sleep duration is common among residents in northeast China. Age, place of residence, and educational level are implicated in both short sleep duration and long sleep duration. Short sleep duration inclines to link with the indices (marital status, alcohol drinking, dietary, obesity, and history of CHD or MI). However, long sleep duration is relevant to the indices (occupation, average monthly earnings, and physical exercise).

Objectively measured sleep and body mass index: a prospective bidirectional study in middle-aged and older adults

BACKGROUND

In recent years, short sleep has been increasingly recognized as a risk factor for obesity. However, current evidence has so far been limited to cross-sectional studies or longitudinal studies using self-reported sleep. Therefore, we explored the directionality of the association between objectively measured sleep and body mass index (BMI).

METHODS

The study consists of 1031 participants from the general population (52% women, 45-91 years at baseline). Sleep, BMI and waist circumference (WC) were measured twice across a follow-up of six years. BMI and WC were measured at the research center. Total sleep time (TST, hrs), sleep onset latency (SOL, min), sleep efficiency (SE, %) and wake after sleep onset (WASO, min) were estimated by a wrist-worn actigraph. In addition, cross-sectional and longitudinal associations in both directions were explored.

RESULTS

An hour shorter TST was cross-sectionally associated with approximately 0.5 kg/m² higher BMI. Longitudinally, longer TST and higher SE were associated with lower BMI (β_TST = -0.75, 95% CI: -1.08, -0.42; β_SE = -0.04, 95% CI: -0.08, -0.01). Conversely, one kg/m² higher BMI was prospectively associated with 0.02 h shorter TST (95% CI: -0.03, -0.01), and this association was more pronounced over time. Results from analyses with WC were in line with those of BMI.

CONCLUSIONS

This is the first study to explore bidirectionality in the association between objectively measured sleep and BMI in a large population of middle-aged and older adults. Indices of poor sleep were associated with higher and less stable BMI across time. Conversely, a high BMI was associated with a decrease in sleep duration. This confirms that the relation between sleep and body size is bidirectional, and changes in either sleep or BMI are likely to co-occur with changes in health through multiple pathways.

The Associations between Dietary Patterns and Short Sleep Duration in Polish Adults (LifeStyle Study)

Short sleep duration appears to put adults at risk of excessive energy intake and obesity; less is known specifically about how sleep quantity relates to dietary patterns. Therefore, the aim of this study was to assess the associations of dietary patterns (DPs) with short sleep duration. The data were collected in November 2016 through a cross-sectional quantitative survey among 972 Polish adults with both normal weight and excessive weight. Principal components analysis (PCA) was conducted to derive DPs. Logistic regression analysis was used to verify associations between short sleep duration (independent variable) and DPs (dependent variables). Five DPs ('Fast foods & sweets'-FF&S; 'Meat & meat products'-M&MP; 'Fruit & vegetable'-F&V; 'Wholemeal food'-WF; and 'Fruit & vegetable juices'-F&VJ) were identified. Adults whose diet was based both on fruit and vegetables (OR 0.62, 95% CI: 0.44⁻0.88; p < 0.01) and on fast food and sweets (OR 0.63, 95% CI: 0.44⁻0.99; p < 0.01) were less likely to be short sleepers on weekdays. On weekdays short sleep duration was associated with smaller odds of FF&S both for men (OR 0.58, 95% CI: 0.33⁻0.97; p < 0.05) and for women (OR 0.61, 95% CI: 0.38⁻0.98; p < 0.05), and with smaller odds of F&V (OR 0.34, 95% CI: 0.20⁻0.58; p < 0.001) for men. Short sleep duration on weekend days was associated with a smaller odds of F&VJ (OR 0.56, 95% CI: 0.30⁻0.96; p < 0.05- only in crude model) and higher odds of F&V (OR 1.70, 95% CI: 1.02⁻3.11; p < 0.05) for women, and with a smaller odds of FF&S (OR 0.37, 95% CI: 0.17⁻0.79; p < 0.05) for men. The number of significant associations between dietary patterns and sleep duration was higher among people with normal weight and overweight compared to those with BMI ≥ 30. We found that both short sleep duration on weekdays and weekend days was associated with some dietary patterns including both healthy and unhealthy DPs. Gender significantly differed these relationships in groups with normal and excessive weight. Findings of the study confirmed the potential effectiveness of combined use of sleep duration and dietary patterns in the development of recommendations for prevention of obesity. Future studies are called for to evaluate these links using dietary patterns identified according to food intake.

Association between Sleep Duration and Overweight/Obesity at Age 7⁻18 in Shenyang, China in 2010 and 2014

This study was designed to examine the association between sleep duration and being overweight/obese in primary, middle, and high school students. This was a multiple cross-sectional study using data from the 2010 and 2014 National Survey on Students’ Constitution and Health (CNSSCH). A total of 23,602 students aged 7–18 years were enrolled in this study. The prevalence of being overweight and obese—stratified by age, gender, and sleep duration—in 2010 and 2014 were compared. Sleep duration was categorized as <7 h, ≥7 to 8 h, ≥8 to 9 h, and ≥9 h. Overweight and obesity were defined according to the cut-point criteria in China. Multivariable logistic regression results in 2010 and 2014 revealed that students sleeping <7 h and aged 7–12 years had an increased risk of becoming overweight/obese. In 2010, the adjusted prevalence ratios of overweight for 7–12-year-old students sleeping <9 h was 1.196 (95%CI: 1.004–1.424) and 13–15-year-old students sleeping <8 h was 1.265 (95%CI: 1.023–1.565). In 2014, the adjusted prevalence ratios of overweight and obesity for 7–12-year-old students sleeping <9 h were 1.295 (95%CI: 1.091–1.537) and 1.231 (95%CI: 1.045–1.449); 16–18-year-old students sleeping <7 h were 1.530 (95%CI: 1.239–1.888) and 1.585 (95%CI: 1.270–2.081). Our study revealed that different levels of sleep curtailment increased the risk of becoming overweight/obesity in different age groups of students.

Sleep and Obesity

Rising global prevalence and incidence of obesity lead to increased cardiovascular-renal complications and cancers. Epidemiological studies reported a worldwide trend towards suboptimal sleep duration and poor sleep quality in parallel with this obesity epidemic. From rodents and human models, it is highly plausible that abnormalities in sleep, both quantity and quality, impact negatively on energy metabolism. While excess dietary intake and physical inactivity are the known drivers of the obesity epidemic, promotion of healthy sleep habits has emerged as a new target to combat obesity. In this light, present review focuses on the existing literature examining the relationship between sleep physiology and energy homeostasis. Notably, sleep dysregulation perturbs the metabolic milieu via alterations in hormones such as leptin and ghrelin, eating behavior, neuroendocrine and autonomic nervous systems. In addition, shift work and trans-meridian air travel may exert a negative influence on the hypothalamic-pituitary-adrenal axis and trigger circadian misalignment, leading to impaired glucose tolerance and increased fat accumulation. Amassing evidence has also suggested that uncoupling of the circadian clock can increase the risk of adverse metabolic health. Given the importance of sleep in maintaining energy homeostasis and that it is potentially modifiable, promoting good sleep hygiene may create new avenues for obesity prevention and treatment.

Is poor sleep associated with obesity in older adults? A narrative review of the literature

INTRODUCTION

To address the worldwide epidemic of obesity, a sizable literature implicates sleep problems in the onset of obesity in younger populations. However, less is known about how this process may operate among older adults, which is of concern, given demographic shifts that have resulted in a much higher proportion of developed nations around the world reaching late life.

METHODS

We offer a current review of the literature studying older adults and examining associations between sleep quality and obesity in this population. We consider both subjective and objectively measured sleep as well as both cross-sectional and longitudinal studies offering stronger causal inference.

RESULTS

We discuss seemingly contradictory literature showing that shorter sleep duration as well as longer sleep duration are associated with obesity risk, then review studies that tested for non-linear relationships and reported a U-shape pattern, suggesting that too much or too little sleep is detrimental. Besides sleep duration, we discuss evidence showing that other forms of sleep dysfunction related to night-time awakenings, REM sleep, slow-wave sleep, and daytime sleepiness, which are indicators of sleep quality, are also linked to obesity. Specific psychological and physiological mediators and moderators, suggesting possible mechanisms whereby sleep problems may affect obesity in older adults, are described.

CONCLUSION

We conclude by discussing areas, where additional research could help clarify this association, considering such factors as medical comorbidities common in late life, and health-related behaviors that may stem from poor sleep (such as disordered eating behavior). Such insights will have great value for clinical practice.

LEVEL OF EVIDENCE

Level V, narrative review.

Relationship of sleep pattern and snoring with chronic disease: findings from a nationwide population-based survey

OBJECTIVES

To investigate the association of total sleep time and presence or absence of snoring with chronic disease among the Bangladeshi adult population.

DESIGN

Cross-sectional survey.

SETTING

Urban and rural Bangladesh.

PARTICIPANTS

A total of 12,338 men and women aged ≥35 years.

MEASUREMENTS

Total sleep time was considered as the total hours of sleep in 24 hours. Furthermore, sleep time was categorized into <7, 7-9, and >9 hours according to National Sleep Foundation (2015) guidelines. Self-reported snoring history was captured and corroborated with their respective sleep partner/spouse in more than 80% cases. Registered physician-diagnosed current and/or previous cases of hypertension, diabetes, coronary heart disease, cancer, stroke, chronic obstructive pulmonary disease, and any other chronic conditions were counted.

RESULTS

Overall prevalence of at least 1 chronic disease in our study population was around 18%: men (15.4%) and women (20.0%). Hypertension has the highest prevalence (overall: 12.7%, men: 12.2%, women: 15%) followed by diabetes (4.9%), coronary heart diseases (3.2%), stroke (1.8%), chronic obstructive pulmonary disease (0.9%), and cancer (any type: 0.1%). Sleep pattern and snoring are significantly associated with all individual chronic disease except cancer. Sociodemographic, behavioral, and lifestyle variables were adjusted, and inadequate total sleep time (<7 hours) and snoring (yes/no) showed significant association with chronic disease status (risk ratio = 1.11, 95% confidence interval 1.00-1.22 and risk ratio = 1.20, 95% confidence interval 1.11-1.29, respectively).

CONCLUSION

Inadequate sleep and snoring are independently associated with chronic disease in Bangladeshi adult population and perhaps elsewhere.

The Risk of Being Obese According to Short Sleep Duration Is Modulated after Menopause in Korean Women

We previously reported that women with short sleep duration consumed more dietary carbohydrate and showed an increased risk for obesity compared to those who slept adequately, but not for men. Using a cross-sectional study of 17,841 Korean women, we investigated the influence of sleep duration on obesity-related variables and consumption of dietary carbohydrate-rich foods in relation to menopausal status. Premenopausal women with short sleep duration had significantly greater body weight (p = 0.007), body mass index (p = 0.003), systolic and diastolic blood pressures (p = 0.028 and p = 0.024, respectively), prevalence of obesity (p < 0.016), and consumption of more carbohydrate-rich foods such as staple foods (p = 0.026) and simple sugar-rich foods (p = 0.044) than those with adequate sleep duration after adjustment for covariates. Premenopausal women with short sleep duration were more obese by 1.171 times compared to subjects adequate sleep duration (95% confidence interval = 1.030–1.330). However, obesity-related variables, dietary consumption, and odds of being obese did not differ according to sleep duration for postmenopausal women. The findings suggest that the increased risk for obesity and consumption of dietary carbohydrate-rich foods with short sleep duration appeared to disappear after menopause in Korean women.

Reduced sleep duration affects body composition, dietary intake and quality of life in obese subjects

PURPOSE

Sleep duration has emerged as a crucial factor affecting body weight and feeding behaviour. The aim of our study was to explore the relationship among sleep duration, body composition, dietary intake, and quality of life (QoL) in obese subjects.

METHODS

Body composition was assessed by DXA. "Sensewear Armband" was used to evaluate sleep duration. SF-36 questionnaire was used to evaluate quality of life (QoL). A 3-day dietary record was administered. Subjects were divided into 2 groups: sleep duration > and ≤300 min/day.

RESULTS

137 subjects (105 women and 32 men), age: 49.8 ± 12.4 years, BMI: 38.6 ± 6.7 kg/m(2), were enrolled. Sleep duration was ≤300 min in 30.6 % of subjects. Absolute and relative fat mass (FM) (40.5 ± 9 vs. 36.5 ± 9.1 kg; 40.2 ± 4.7 vs. 36.9 ± 5.6 %), and truncal fat mass (19.2 ± 6.1 vs. 16.6 ± 5 kg; 38.6 ± 5.3 vs. 35.2 ± 5.5 %) were higher in subjects sleeping ≤300 min when compared to their counterparts (all p < 0.05), whereas just a tendency towards a higher BMI was observed (p = 0.077). Even though energy intake was not different between groups, subjects sleeping ≤300 min reported a higher carbohydrate consumption per day (51.8 ± 5.1 vs. 48.4 ± 9.2 %, p = 0.038). SF-36 total score was lower in subjects sleeping ≤300 min (34.2 ± 17.8 vs. 41.4 ± 12.9, p = 0.025). Sleep duration was negatively associated with FM (r = -0.25, p = 0.01) and SF-36 total score (r = -0.31, p < 0.001). The inverse association between sleep duration and SF-36 total score was confirmed by the regression analysis after adjustment for BMI and fat mass (R = 0.43, R (2) = 0.19, p = 0.012).

CONCLUSION

Reduced sleep duration negatively influences body composition, macronutrient intake, and QoL in obese subjects.

Sleep Duration and Obesity in Adults: What Are the Connections?

Collectively, cross-sectional and longitudinal studies on self-reported sleep duration and obesity do not show a clear pattern of association with some showing a negative linear relationship, some showing a U-shaped relationship, and some showing no relationship. Associations between sleep duration and obesity seem stronger in younger adults. Cross-sectional studies using objectively measured sleep duration (actigraphy or polysomnography (PSG)) also show this mixed pattern whereas all longitudinal studies to date using actigraphy or PSG have failed to show a relationship with obesity/weight gain. It is still too early and a too easy solution to suggest that changing the sleep duration will cure the obesity epidemic. Given novel results on emotional stress and poor sleep as mediating factors in the relationship between sleep duration and obesity, detection and management of these should become the target of future clinical efforts as well as future research.

Associations between sleep characteristics and weight gain in an older population: results of the Heinz Nixdorf Recall Study

BACKGROUND/OBJECTIVES

Sleep duration influences weight change in children and young adults, but there is less evidence in middle-aged, and, in particular, older adults. We assessed associations between sleep duration, daytime napping and sleep disturbances, respectively, with change of weight and waist circumference in older subjects. Contrary to previous studies, we also used two points in time to assess sleep characteristics.

METHODS

We used data from the population-based Heinz Nixdorf Recall study, a cohort study in Germany with a baseline and two follow-up visits (age 45-74 years, median follow-up 5.1 years for first, 5.2 years for second follow-up visit). In adjusted linear regression models (N=3751), we estimated weight change between baseline and first follow-up visit in relation to various self-reported sleep characteristics measured at baseline. Furthermore, we estimated change of weight and waist circumference, respectively, between first and second follow-up visit in relation to patterns of sleep characteristics measured at baseline and at the first follow-up visit (N=2837).

RESULTS

In all analyses, short and long sleep duration, sleep disturbances, and regular daytime napping were associated with <1 kg of weight gain and <1 cm of gain in waist circumference over 5 years compared with the respective reference categories. For example, compared with 7-<8 h night sleep, short night sleep (⩽5 h at baseline) was associated with 0.5 kg of weight gain (95% confidence interval: -0.1; 1.1 kg).

CONCLUSIONS

Our study gave no evidence that sleep characteristics were associated with clinically relevant weight gain in the older population.

The Link Between Inadequate Sleep and Obesity in Young Adults

The prevalence of obesity has increased dramatically over the past decade. Although an imbalance between caloric intake and physical activity is considered a key factor responsible for the increase, there is emerging evidence suggesting that other factors may be important contributors to weight gain, including inadequate sleep. Overall research evidence suggests that inadequate sleep is associated with obesity. Importantly, the strength and trajectory of the association seem to be influenced by multiple factors including age. Although limited, the emerging evidence suggests young adults might be at the center of a "perfect health storm," exposing them to the highest risk for obesity and inadequate sleep. Unfortunately, the methods necessary for elucidating the complex relationship between sleep and obesity are lacking. Uncovering the underlying factors and trajectories between inadequate sleep and weight gain in different populations may help to identify the windows of susceptibility and to design targeted interventions to prevent the negative impact of obesity and related diseases.

Restriction of rapid eye movement sleep during adolescence increases energy gain and metabolic efficiency in young adult rats

NEW FINDINGS

What is the central question of this study? Sleep curtailment in infancy and adolescence may lead to long-term risk for obesity, but the mechanisms involved have not yet been determined. This study examined the immediate and long-term metabolic effects produced by sleep restriction in young rats. What is the main finding and its importance? Prolonged sleep restriction reduced weight gain (body fat stores) in young animals. After prolonged recovery, sleep-restricted rats tended to save more energy and to store more fat, possibly owing to increased gross food efficiency. This could be the first step to understand this association. Sleep curtailment is associated with obesity and metabolic changes in adults and children. The aim of the present study was to evaluate the immediate and long-term metabolic alterations produced by sleep restriction in pubertal male rats. Male Wistar rats (28 days old) were allocated to a control (CTL) group or a sleep-restricted (SR) group. This was accomplished by the single platform technique for 18 h per day for 21 days. These groups were subdivided into the following four time points for assessment: sleep restriction and 1, 2 and 4 months of recovery. Body weight and food intake were monitored throughout the experiment. At the end of each time period, blood was collected for metabolic profiling, and the carcasses were processed for measurement of body composition and energy balance. During the period of sleep restriction, SR animals consumed less food in the home cages. This group also displayed lower body weight, body fat, triglycerides and glucose levels than CTL rats. At the end of the first month of recovery, despite eating as much as CTL rats, SR animals showed greater energy and body weight gain, increased gross food efficiency and decreased energy expenditure. At the end of the second and fourth months of recovery, the groups were no longer different, except for energy gain and gross food efficiency, which remained higher in SR animals. In conclusion, sleep restriction affected weight gain of young animals, owing to reduction of fat stores. Two months were sufficient to recover this deficit and to reveal that SR rats tended to save more energy and to store more fat.

The role of sleep in the regulation of body weight

Sleep participates in the regulation of body weight. The amount of sleep and synchronization of the biological clock are both necessary to achieve the energy balance and the secretion of hormones that contribute to weight regulation. In this review, we first reconsider what normal physiological sleep is and what the normative values of sleep are in the general population. Second, we explain how the biological clock regulates the hormones that may be involved in weight control. Third, we provide some recent data on how sleep may be disturbed by sleep disorders or reduced by sleep debt with consequences on weight. Finally, we explore the relationships between sleep debt and obesity.

Relationship between sleep duration and body mass index depends on age

OBJECTIVE

Sleep duration is associated with obesity and cardiometabolic disease. It is unclear, though, how these relationship differs across age groups.

METHODS

Data from 2007 to 2008 National Health and Nutrition Examination Survey (NHANES) were used, including respondents aged 16+ with complete data (N = 5,607). Sleep duration and age were evaluated by self-report, and body mass index (BMI) was assessed objectively. Sleep duration was evaluated continuously and categorically [very short (≤4 h), short (5-6 h), and long (≥9 h) versus average (7-8 h)]. Age was also evaluated continuously and categorically [adolescent (16-17 years), young adult (18-29 years), early middle age (30-49 years), late middle age (50-64 years), and older adult (≥65 years)].

RESULTS

There was a significant interaction with age for both continuous (Pinteraction  = 0.014) and categorical (Pinteraction  = 0.035) sleep duration. A pseudo-linear relationship was seen among the youngest respondents, with the highest BMI associated with the shortest sleepers and the lowest BMI associated with the longest sleepers. This relationship became U-shaped in middle-age, and less of a relationship was seen among the oldest respondents.

CONCLUSIONS

These findings may provide insights for clinical recommendations and could help to guide mechanistic research regarding the sleep-obesity relationship.

Relationship between Duration of Sleep and Hypertension in Adults: A Meta-Analysis

OBJECTIVES

Epidemiologic studies have shown that chronic short sleep may be associated with the development of hypertension; however, the results are controversial. This meta-analysis was conducted to determine whether the duration of sleep is associated with hypertension.

METHODS

Reference databases (PubMed, EmBase, the Cochrane Library, Chinese Biological Medicine database) were searched for studies related to sleep duration and hypertension. Sleep duration categories (≤ 5 h, 6 h, 7 h, 8 h, ≥ 9 h) and prevalence or incidence of hypertension in each sleep category were extracted. A general analysis and subgroup analyses stratified by gender, age, study design, and different definitions of sleep duration were conducted to evaluate the relationship between sleep duration and hypertension.

RESULTS

Thirteen articles out of a total of 1,628 articles involving 347,759 participants met the inclusion criteria. A U-shaped change in pooled odds ratios (ORs) for hypertension due to the change of sleep duration was observed. The unadjusted OR for hypertension of individuals who slept ≤ 5 h vs. 7 h was 1.61, 95% CI = 1.28-2.02; those who slept ≥ 9 h vs. 7 h was 1.29, 95% CI = 0.97-1.71. The pooled ORs were still significant after adjusted by age and gender. Women deprived of sleep (sleep time ≤ 5 h vs. 7 h, OR = 1.68, 95% CI = 1.39-2.03) had a higher risk of hypertension than men (OR = 1.30, 95% CI = 0.93-1.83).

CONCLUSION

Excessively longer and shorter periods of sleep may both be risk factors for high blood pressure; these associations are stronger in women than men.

Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, Dinges DF, Gangwisch J, Grandner MA, Kushida C, Malhotra RK, Martin JL, Patel SR, Quan SF, Tasali E. Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society on the Recommended Amount of Sleep for a Healthy Adult: Methodology and Discussion

The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address important assumptions and challenges encountered during the consensus process. Finally, we outline future directions that will advance our understanding of sleep need and place sleep duration in the broader context of sleep health.

Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, Dinges DF, Gangwisch J, Grandner MA, Kushida C, Malhotra RK, Martin JL, Patel SR, Quan SF, Tasali E. Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society on the Recommended Amount of Sleep for a Healthy Adult: Methodology and Discussion

The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address important assumptions and challenges encountered during the consensus process. Finally, we outline future directions that will advance our understanding of sleep need and place sleep duration in the broader context of sleep health.

Prolonged REM sleep restriction induces metabolic syndrome-related changes: Mediation by pro-inflammatory cytokines

Chronic sleep restriction in human beings results in metabolic abnormalities, including changes in the control of glucose homeostasis, increased body mass and risk of cardiovascular disease. In rats, 96h of REM sleep deprivation increases caloric intake, but retards body weight gain. Moreover, this procedure increases the expression of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), which may be involved with the molecular mechanism proposed to mediate insulin resistance. The goal of the present study was to assess the effects of a chronic protocol of sleep restriction on parameters of energy balance (food intake and body weight), leptin plasma levels and its hypothalamic receptors and mediators of the immune system in the retroperitoneal adipose tissue (RPAT). Thirty-four Wistar rats were distributed in control (CTL) and sleep restriction groups; the latter was kept onto individual narrow platforms immersed in water for 18h/day (from 16:00h to 10:00h), for 21days (SR21). Food intake was assessed daily, after each sleep restriction period and body weight was measured daily, after the animals were taken from the sleep deprivation chambers. At the end of the 21day of sleep restriction, rats were decapitated and RPAT was obtained for morphological and immune functional assays and expression of insulin receptor substrate 1 (IRS-1) was assessed in skeletal muscle. Another subset of animals was used to evaluate blood glucose clearance. The results replicated previous findings on energy balance, e.g., increased food intake and reduced body weight gain. There was a significant reduction of RPAT mass (p<0.001), of leptin plasma levels and hypothalamic leptin receptors. Conversely, increased levels of TNF-α and IL-6 and expression of phosphorylated NFκ-β in the RPAT of SR21 compared to CTL rats (p<0.01, for all parameters). SR21 rats also displayed reduced glucose clearance and IRS-1 expression than CTL rats (p<0.01). The present results indicated that 21days of sleep restriction by the platform method induced metabolic syndrome-related alterations that may be mediated by inflammation of the RPAT.

Association between actigraphic sleep metrics and body composition

PURPOSE

Determine if individuals with poor sleep characteristics (i.e., late sleep onset or wake times, short sleep duration, long sleep latency, low sleep efficiency, high wake after sleep onset) have greater body mass index (BMI = kg/m(2)) or body fat.

METHODS

Data for these cross-sectional analyses were from the Energy Balance Study (University of South Carolina). Participants were between 21 and 35 years of age and had a BMI of 20 to 35 kg/m(2). Body fat percent was measured by dual X-ray absorptiometry. Sleep and physical activity were measured by actigraphy (BodyMedia's SenseWear physical activity armband). General linear models were used to estimate mean BMI and body fat percent by sleep metric categories.

RESULTS

Greater BMI and body fat percent were associated with low sleep efficiency (BMI = 25.5 vs. 24.8 kg/m(2), P < .01; body fat = 27.7% vs. 26.5%, P = .04) and high wake after sleep onset (BMI = 25.6 vs. 25.0 kg/m(2), P = .02; body fat = 28.0% vs. 26.7%, P = .03). Elevated BMI or body fat percent also were observed for later wake times, shorter sleep duration, and longer sleep latency. Sex modified the association between wake times and body composition.

CONCLUSIONS

Understanding the complex relationships between sleep and health outcomes could help reduce chronic disease burden by incorporating sleep components, measured through novel noninvasive techniques (SenseWear armband), into weight loss interventions.

Sleep duration associated with body mass index among Chinese adults

OBJECTIVE

The objective of this study was to investigate the relationship between sleep duration and obesity among Chinese adults.

METHODS

A community-based cross-sectional study was conducted among Chinese adults in 2008. In total, 3225 participants were selected by a multistage cluster sampling method. Self-reported sleep duration was measured by a standardized questionnaire. Logistic regression models were used to estimate the odds ratios (ORs) (95% confidence intervals, CIs) of obesity with sleep duration, separated by gender, and adjusted for age, education, occupation, marriage, smoking, drinking, body pain, and health status.

RESULTS

The mean sleep duration was 7.8 h. Among the 2962 participants, 7.2% had short sleep duration (≤6 h/day). There were 171 obese participants (5.7%) in this population. After adjustment for age, short sleep duration (<6 h) was significantly associated with obesity among men (OR: 2.15; 95% CI: 1.193.90), but not among women; additional adjustment for potential confounders did not attenuate the association among men. Increasing sleep duration (a continuous variable) was significantly and negatively associated with obesity in women after adjustment for education level, occupation, marital status, smoking, drinking, body pain, and health status. The adjusted OR per-hour increase in sleep duration was 0.74 (0.56-0.97) for obesity, suggesting that for a 1-h increase in sleep duration among women, obesity risk decreased by 26%.

CONCLUSION

Short sleep duration was associated with increasing obesity in Chinese men, and sleep duration was associated with obesity in Chinese women, although the underlying mechanism is unclear. This possible gender difference warrants further studies.