Associations of self-reported and actigraphy-assessed sleep characteristics with body mass index and waist circumference in adults: moderation by gender

Physical activity and sleep moderate the relationship between stress and screen time in college-aged adults

For undergraduate students, excessive screen time is associated with poorer mental health and greater perceived stress. Objective: The purpose of the present investigation was to determine the potential moderating influence of physical activity and sleep on the relationship between screen time and stress. Participants & Methods: A cross-sectional sample of 513 undergraduate students between Fall 2017 & Spring 2020 were given a questionnaire to assess perceived stress level, physical activity engagement, screen time, and sleep. Results: Stepwise hierarchical regression analyses identified that screen time, sleep, and the three-way interaction between screen time, sleep, and physical activity were associated with stress. Post-hoc decomposition revealed that higher levels of physical activity and sleep both mitigated the relationship between screen time and stress. Conclusions: Findings suggest that modifiable health behaviors such as physical activity and sleep may be important factors for managing the negative effects of screen time on stress in college-aged adults.

Objectively measured daytime sleepiness predicts weight change among adults: Findings from the Wisconsin Sleep Cohort Study

OBJECTIVE

Body mass index (BMI) trajectories are associated with night-time sleep, but it is not clear how they relate to daytime sleepiness in population data. This study aimed to examine longitudinal associations between levels and changes in daytime sleepiness and BMI trajectories among men and women.

METHODS

We estimated growth curve models among 827 participants in the Wisconsin Sleep Cohort Study (mean [sd] age = 55.2 [8.0] years at baseline). The outcome variable was BMI (kg/m2) and the key predictor was daytime sleepiness measured by Multiple Sleep Latency Test (MSLT) scores. Covariates included demographics, health behaviors, retirement status, stimulant use, and depressive symptoms. In sensitivity analyses, we evaluated the potential effects of cardiovascular disease, shift work status, and sleep apnea on the robustness of sleepiness and BMI associations.

RESULTS

At the between-person level, men who were sleepier had higher BMI levels. At the within-person level, age moderated the positive association between sleepiness and BMI among women. Specifically, young women who became sleepier over time gained more BMI than older women with comparable increases in sleepiness. Furthermore, while BMI tended to increase with age among women, BMI trajectories were steeper among sleepy women than among well-rested women, who experienced less increase in BMI over time.

CONCLUSION

The study suggested that levels and changes in daytime sleepiness as objectively measured by MSLT scores are associated with body mass among adults.

Subjective versus objective sleep in men with Klinefelter syndrome

OBJECTIVES

To investigate sleep among men with Klinefelter syndrome (KS).

METHOD

We compared the sleep domains latency, disturbance, and efficiency in 30 men with KS (M age = 36.7 years, SD = 10.6) to 21 age-matched non-KS controls (M age = 36.8 years, SD = 14.4). Actigraphs were used to objectively measure sleep across 7 days and nights. Participants also completed a sleep diary over the same period, and the Pittsburgh Sleep Quality Index (PSQI).

RESULTS

The mean correlation between the objective and subjective sleep measures was lower for the KS sample (M r = .15) than for controls (M r = .34). Sleep disturbance was significantly larger in the KS sample, as measured by actigraphy (p = .022, d = 0.71) and the PSQI (p = .037, d = 0.61). In regression models predicting sleep domains from KS status, age, educational level, vocational status, IQ, and mental health, KS status was not a significant predictor. Higher age was associated with more actigraphy-measured sleep disturbance. Higher educational level and being employed were associated with better sleep efficiency.

CONCLUSIONS

Sleep disturbance may be a particular problem for men with KS and should be measured with complimentary methods.

The interplay between macronutrients and sleep: focus on circadian and homeostatic processes

Sleep disturbances are an emerging risk factor for metabolic diseases, for which the burden is particularly worrying worldwide. The importance of sleep for metabolic health is being increasingly recognized, and not only the amount of sleep plays an important role, but also its quality. In this review, we studied the evidence in the literature on macronutrients and their influence on sleep, focusing on the mechanisms that may lay behind this interaction. In particular, we focused on the effects of macronutrients on circadian and homeostatic processes of sleep in preclinical models, and reviewed the evidence of clinical studies in humans. Given the importance of sleep for health, and the role of circadian biology in healthy sleep, it is important to understand how macronutrients regulate circadian clocks and sleep homeostasis.

Weight Loss and Sleep, Current Evidence in Animal Models and Humans

Sleep is a vital process essential for survival. The trend of reduction in the time dedicated to sleep has increased in industrialized countries, together with the dramatic increase in the prevalence of obesity and diabetes. Short sleep may increase the risk of obesity, diabetes and cardiovascular disease, and on the other hand, obesity is associated with sleep disorders, such as obstructive apnea disease, insomnia and excessive daytime sleepiness. Sleep and metabolic disorders are linked; therefore, identifying the physiological and molecular pathways involved in sleep regulation and metabolic homeostasis can play a major role in ameliorating the metabolic health of the individual. Approaches aimed at reducing body weight could provide benefits for both cardiometabolic risk and sleep quality, which indirectly, in turn, may determine an amelioration of the cardiometabolic phenotype of individuals. We revised the literature on weight loss and sleep, focusing on the mechanisms and the molecules that may subtend this relationship in humans as in animal models.

The association between sleep duration and detailed measures of obesity: A cross sectional analysis in the ADDITION-PRO study

Background

Sleep duration is associated with BMI and waist circumference. However, less is known about whether sleep duration affects different measurements of obesity differently.

Objective

To investigate the association between sleep duration and different measures of obesity.

Methods

In this cross-sectional analysis 1309, Danish, older adults (55% men) completed at least 3 days of wearing a combined accelerometer and heart rate-monitor for assessing sleep duration (hours/night) within self-reported usual bedtime. Participants underwent anthropometry and ultrasonography to assess BMI, waist circumference, visceral fat, subcutaneous fat, and fat percentage. Linear regression analyses examined the associations between sleep duration and obesity-related outcomes.

Results

Sleep duration was inversely associated with all obesity-related outcomes, except visceral-/subcutaneous-fat-ratio. After multivariate adjustment the magnitude of associations became stronger and statistically significant for all outcomes except visceral-/subcutaneous-fat-ratio, and subcutaneous fat in women. The associations with BMI and waist circumference demonstrated the strongest associations, when comparing standardized regression coefficients.

Conclusions

Shorter sleep duration were associated with higher obesity across all outcomes except visceral-/subcutaneous-fat-ratio. No specifically salient associations with local or central obesity were observed. Results suggest that poor sleep duration and obesity correlate, however, further research is needed to conclude on beneficial effects of sleep duration regarding health and weight loss.

Chronobiology and Metabolism: Is Ketogenic Diet Able to Influence Circadian Rhythm?

Circadian rhythms underpin most physiological processes, including energy metabolism. The core circadian clock consists of a transcription-translation negative feedback loop, and is synchronized to light-dark cycles by virtue of light input from the retina, to the central clock in the suprachiasmatic nucleus in the hypothalamus. All cells in the body have circadian oscillators which are entrained to the central clock by neural and humoral signals. In addition to light entrainment of the central clock in the brain, it now emerges that other stimuli can drive circadian clock function in peripheral tissues, the major one being food. This can then drive the liver clock to be misaligned with the central brain clock, a situation of internal misalignment with metabolic disease consequences. Such misalignment is prevalent, with shift workers making up 20% of the working population. The effects of diet composition on the clock are not completely clarified yet. High-fat diet and fasting influence circadian expression of clock genes, inducing phase-advance and phase-delay in animal models. Ketogenic diet (KD) is able to induce a metabolic switch from carbohydrate to fatty acid oxidation, miming a fasting state. In recent years, some animal studies have been conducted to investigate the ability of the KD to modify circadian gene expression, and demonstrated that the KD alters circadian rhythm and induces a rearrangement of metabolic gene expression. These findings may lead to new approaches to obesity and metabolic pathologies treatment.

Habitual sleep, sleep duration differential, and weight change among adults: Findings from the Wisconsin Sleep Cohort Study

OBJECTIVES

Assess longitudinal associations between diary-measured sleep duration and clinically assessed body mass index (BMI).

DESIGN

Multilevel growth curve analyses examined how within-person changes and between-person differences in habitual sleep duration were associated with BMI trajectories.

SETTING

Sleep diaries across 2-6 consecutive weekday and weekend nights at each data collection point, repeatedly collected at approximate 4-year intervals, for an average of 9.2 (standard deviation [SD] = 3.6) years between 1989 and 2011.

PARTICIPANTS

About 784 participants (47% women) enrolled in the Wisconsin Sleep Cohort Study (mean [SD] age = 51.1 [8.0] years at baseline).

MEASUREMENTS

The outcome variable was BMI (kg/m²). Key predictors were habitual sleep duration (defined as average weekday nighttime sleep duration) and sleep duration differential (defined as the difference between average weekday and average weekend nighttime sleep duration) at each data collection wave.

RESULTS

Men with shorter habitual sleep duration on weekdays had higher BMI than men with longer habitual sleep duration on weekdays (β = -0.90 kg/m²/hour, se = 0.34, p = .008). Participants with larger differentials between weekday and weekend sleep duration experienced more rapid BMI gain over time for both men (β = 0.033 kg/m²/year per hour differential, se = 0.017, p = .044) and women (β = 0.057 kg/m²/year per hour differential, se = 0.027, p = .036).

CONCLUSION

This study suggests that habitual short sleep is associated with higher BMI levels in men and that a larger weekday-weekend sleep differential is associated with increasing BMI trajectories among both men and women in mid-to-late life.

Associations of Diet Quality and Sleep Quality with Obesity

Short sleep duration or poor sleep quality has been associated with an increased risk of obesity. Although the underlying mechanism remains unclear, one proposed pathway is poor diet quality. This cross-sectional study investigated whether diet quality modifies the association between sleep status and obesity in Korean adults. We used the baseline data and samples of 737 men and 428 women (n = 1165) aged 19–64, who participated in the prospective Ewha–Boramae cohort study. Sleep duration was dichotomized into ≥7 h (adequate) and <7 h (insufficient). Pittsburgh Sleep Quality Index (PSQI) values, reflecting sleep quality, were dichotomized into >5 (poor quality) and ≤5 (good quality). Diet quality was evaluated by the Recommended Food Score (RFS). Obesity was associated with higher rates of insufficient sleep and poor sleep quality in women, but not in men. After adjustment for covariates, women with poor sleep quality had a higher risk of obesity than women with good sleep quality (OR = 2.198; 95% CI = 1.027–4.704); this association occurred only in the group with RFS ≤ median score. Our findings support a significant association between sleep quality and obesity, and this association has been potentially modified by dietary quality in women.

Is sleep associated with BMI, waist circumference, and diet among long-term colorectal cancer survivors? Results from the population-based PROFILES registry

PURPOSE

In the general population, poor sleep quality and short sleep duration are associated with a higher body mass index (BMI) and waist circumference (WC), and an unhealthy diet. The aim of this study was to assess if the association between sleep quality and duration and BMI, WC, and diet quality also exists among colorectal cancer (CRC) survivors, as many CRC survivors have an unhealthy weight and diet.

METHODS

Cross-sectional data from a longitudinal CRC cohort were used. In this study, survivors were 4-13 years post diagnosis. The Pittsburgh Sleep Quality Index (PSQI) was used to assess both sleep quality and sleep duration. Diet quality was assessed by scoring adherence (low, moderate, high) to the 2007 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) recommendations of five food groups and nutrients: fruit and vegetables, dietary fiber, red and processed meat, alcoholic beverages, and sugary drinks, using a brief diet screener. BMI and WC were self-measured. Associations were analyzed by multivariable linear and multinomial logistic regression analyses.

RESULTS

Among 1002 CRC survivors, 23% reported poor sleep quality (PSQI score ≥ 8) and 24% reported short sleep duration (≤ 6 h). No associations between sleep and BMI, WC, and diet quality were found.

CONCLUSION

Sleep problems are common in long-term CRC survivors; however, sleep quality and duration was not associated with BMI, WC, and diet quality in this population. It is unknown why the results differ from findings in the general population.

Cross-sectional and prospective associations between sleep regularity and metabolic health in the Hispanic Community Health Study/Study of Latinos

STUDY OBJECTIVES

Sleep is an emergent, multi-dimensional risk factor for diabetes. Sleep duration, timing, quality, and insomnia have been associated with diabetes risk and glycemic biomarkers, but the role of sleep regularity in the development of metabolic disorders is less clear.

METHODS

We analyzed data from 2107 adults, aged 19-64 years, from the Sueño ancillary study of the Hispanic Community Health Study/Study of Latinos, followed over a mean of 5.7 years. Multivariable-adjusted complex survey regression methods were used to model cross-sectional and prospective associations between the sleep regularity index (SRI) in quartiles (Q1-least regular, Q4-most regular) and diabetes (either laboratory-confirmed or self-reported antidiabetic medication use), baseline levels of insulin resistance (HOMA-IR), beta-cell function (HOMA-β), hemoglobin A1c (HbA1c), and their changes over time.

RESULTS

Cross-sectionally, lower SRI was associated with higher odds of diabetes (odds ratio [OR]Q1 vs. Q4 = 1.64, 95% CI: 0.98-2.74, ORQ2 vs. Q4 = 1.12, 95% CI: 0.70-1.81, ORQ3 vs. Q4 = 1.00, 95% CI: 0.62-1.62, ptrend = 0.023). The SRI effect was more pronounced in older (aged ≥ 45 years) adults (ORQ1 vs. Q4 = 1.88, 95% CI: 1.14-3.12, pinteraction = 0.060) compared to younger ones. No statistically significant associations were found between SRI and diabetes incidence, as well as baseline HOMA-IR, HOMA-β, and HbA1c values, or their changes over time among adults not taking antidiabetic medication.

CONCLUSIONS

Our results suggest that sleep regularity represents another sleep dimension relevant for diabetes risk. Further research is needed to elucidate the relative contribution of sleep regularity to metabolic dysregulation and pathophysiology.

Changes in dietary inflammatory potential predict changes in sleep quality metrics, but not sleep duration

STUDY OBJECTIVES

Non-pharmacological sleep interventions may improve sleep profiles without the side-effects observed with many pharmacological sleep aids. The objective of this research was to examine the association between sleep and inflammation and to examine how changes in dietary inflammatory potential influence changes in sleep.

METHODS

The Inflammation Management Intervention Study (IMAGINE), which was a dietary intervention designed to lower inflammation, provided access to 24-h dietary recalls (24HR), objectively measured sleep using SensewearTM armbands, and a range of self-reported demographics, health histories, lifestyle behaviors, psychosocial metrics, anthropometric measurements, and inflammatory biomarkers. Dietary Inflammatory Index® (DII®) scores were calculated from three unannounced 24HR-derived estimated intakes of whole foods and micro and macronutrients over a 2-week period at baseline and post-intervention (i.e. month 3). Statistical analyses primarily utilized linear regression.

RESULTS

At baseline, for every 1-min increase in sleep onset latency, tumor necrosis factor-α increased by 0.015 pg/mL (±0.008, p = 0.05). Every one-percentage increase in sleep efficiency was associated with decreased C-reactive protein (CRP) of -0.088 mg/L (±0.032, p = 0.01). Every 1-min increase in wake-after-sleep-onset (WASO) increased both CRP and interleukin-6. Compared to participants with pro-inflammatory DII changes over 3 months, those with anti-inflammatory changes decreased WASO (0 vs. -25 min, respectively, p < 0.01) and improved sleep efficiency (-2.1% vs. +2.6%, respectively, p = 0.04).

CONCLUSIONS

Non-pharmacological treatments, such as anti-inflammatory diets, may improve sleep in some adults. Future research involving dietary treatments to improve sleep should not only focus on the general population, but also in those commonly experiencing co-morbid sleep complaints.

CLINICAL TRIAL INFORMATION

NCT02382458.

Racial disparities in sleep health between Black and White young adults: The role of neighborhood safety in childhood

OBJECTIVES

Black adults in the United States have shorter sleep durations and poorer sleep efficiency relative to White adults, yet reasons for these disparities are not well explicated. The objective of this study was to examine neighborhood safety in childhood as a mediator of subsequent racial disparities in sleep.

METHODS

Data were from Black and White young adults attending a large, predominantly White university in the Southeastern United States (N = 263; 52% Black, 53% female; Mean age = 19.21 years, SD = 1.01). Sleep parameters were assessed from eight nights of wrist actigraphy (time in bed, sleep duration, and efficiency) and an established self-report measure of daytime sleepiness. Residential histories from birth through age 18 were documented, and retrospective self-reports of neighborhood safety in childhood were assessed.

RESULTS

Black participants had less time in bed (p < 0.001), shorter sleep duration (p < 0.001), poorer sleep efficiency (p < 0.001), and more daytime sleepiness (p = 0.009) than White participants. Neighborhood safety mediated race differences in time in bed (p = 0.028), sleep duration (p = 0.033), and daytime sleepiness (p = 0.048), but not sleep efficiency. Findings were substantively unchanged after adjustment for family socioeconomic status, BMI, and substance use.

CONCLUSIONS

Findings support the hypothesis that neighborhood safety in childhood may partially account for race differences in subsequent sleep duration and daytime sleepiness. Addressing racial inequities in childhood neighborhood safety may be an important step toward reducing racial disparities in sleep health.

Association between habitual sleep duration/quality and appetite markers in individuals with obesity

STUDY OBJECTIVES

To assess if habitual sleep duration/quality was associated with appetite in individuals with obesity, and if the association was modulated by sex.

METHODS

Sleep duration/quality was measured with Pittsburgh Sleep Quality Index score in 95 healthy adults with obesity (BMI: 36.6 ± 4.2 kg/m²). Subjective feelings of appetite were assessed using visual analogue scales, and plasma concentrations of active ghrelin, total peptide YY, active glucagon-like peptide 1, cholecystokinin (CCK) and insulin were measured in fasting and every 30 min up to 2.5 h after a meal.

RESULTS

No significant associations were found between sleep duration, or overall quality, and appetite in all participants. However, a worse sleep efficiency was associated with lower postprandial CCK, a shorter habitual sleep was associated with lower postprandial desire to eat and a lower daytime dysfunction was associated with higher prospective food consumption in fasting (P<0.05, for all). In males, a shorter habitual sleep duration and a worse subjective sleep quality were associated with increased basal and postprandial active ghrelin (P<0.05, P<0.01, P<0.01 and P<0.05, respectively). Also, a shorter habitual sleep was associated with lower basal and postprandial insulin (P<0.05 for both) and a worse overall sleep quality with lower postprandial insulin (P<0.05). In females, a worse overall sleep quality was associated with lower postprandial active ghrelin (P<0.05), and short habitual sleep with higher postprandial insulin (P<0.05).

CONCLUSION

A worse habitual sleep efficiency is associated with blunted postprandial CCK secretion in individuals with obesity. The association between habitual sleep duration/quality and insulin and active ghrelin seems to be modulated by sex, but more studies are needed to confirm these findings.

Sleep Characteristics and Cerebrospinal Fluid Progranulin in Older Adults: The CABLE Study

Cerebrospinal fluid (CSF) progranulin (PGRN) is related to various neurodegeneration diseases. And sleep problems can cause abnormality in protein metabolism in vivo. We aim to explore the potential associations between the self-reported sleep characteristics and CSF PGRN in cognitively intact older adults. Our study recruited 747 participants (mean (standard deviation (SD)) age, 61.99 (10.52) years, 329 (42.89%) females) who had normal cognition from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study with CSF PGRN and sleep characteristics measured. The multiple linear regression and nonlinear regression adjusted for age, gender, education, and apolipoprotein E-epsilon 4 gene (APOE4) status were used to assess the associations between sleep characteristics and PGRN. Interaction effects were explored between APOE4 status and sleep characteristics on CSF PGRN level. Sleep disturbances indicated lower CSF PGRN (β = - 0.0186, p = 0.0160). For detailed items in sleep disturbances, lower CSF PGRN was found in males who woke up during sleep (β = - 0.0121, p = 0.0062) and in females who had breathing difficulties (β = - 0.0258, p = 0.0271). Meanwhile, sleep efficiency was associated with CSF PGRN (β = - 0.0512, p = 0.0497). No significant interaction effects between sleep characteristics and APOE4 status were found. Meanwhile, we did not find a nonlinear relationship between nocturnal sleep duration and CSF PGRN. Sleep problems may influence the metabolism of PGRN, thus attenuating the protective effects of PGRN on neurodegeneration diseases.

Patterns and correlates of sleep duration in the Southern cohort community study

OBJECTIVE

To investigate whether race (African American (AA) and white) is associated with sleep duration among adults from low socioeconomic (SES) strata and whether SES status, lifestyle behaviors, or health conditions are associated with sleep duration within race-sex groups.

METHODS

This cross-sectional study includes 78,549 participants from the Southern Community Cohort Study (SCCS). Averaged daily sleep duration was assessed by weighted averages of self-reported sleep duration on weekdays and weekends. Adjusted odds ratios (ORs) of very short (<5 h/day), short (5-6 h/day), and long sleep (≥9 h/day) associated with pre-selected risk factors in each race-sex group were determined by multinomial logistic models.

RESULTS

The prevalence of very short and short sleep was similar among AAs (6.2% and 29.1%) and whites (6.5% and 29.1%). Long sleep was considerably more prevalent among AAs (19.3%) than whites (13.0%). Very short sleep was associated with lower education and family income, with stronger associations among whites. Higher physical activity levels significantly decreased odds for both very short (OR = 0.80) and long sleep (OR = 0.78). Smoking, alcohol use, and dietary intake were not associated with sleep duration. Regardless of race or sex, very short, short, and long sleep were significantly associated with self-reported health conditions, especially depression (ORs were 2.06, 1.33, and 1.38, respectively).

CONCLUSIONS

Sleep duration patterns differed between AAs and whites from the underrepresented SCCS population with low SES. Sleep duration was associated with several socioeconomic, health behaviors, and health conditions depending on race and sex.

Housework, health, and well-being in older adults: The role of socioeconomic status

For most adults, household chores are undesirable tasks yet need to be completed regularly. Previous research has identified absolute hours spent on household chores and one's perceived fairness of the housework distribution as predictors of romantic relationship quality and well-being outcomes. Drawing from the Equity Theory, we hypothesized that perceived fairness acts as an underlying psychological mechanism linking household chores hours to long-term effects of relationship quality, well-being, physical health, and sleep quality in a sample of 2,644 married and cohabiting adults from the Midlife Development in the U.S. study. Additionally, following the Reserve Capacity Model, socioeconomic status (SES) was tested as a moderator because of its association with exposure to stressors and psychological resources which contribute to perceived fairness. Moderated mediation results showed significant indirect effects of household chore hours through perceived fairness on prospective measures of well-being, marital quality, physical health, and sleep dysfunction among individuals of lower SES but not higher SES when controlling for age, sex, and paid work hours. These results highlight the importance of perceived fairness and the influence of SES in the links among household chores and long-term relationship processes, health, and well-being. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Sleep parameters measured by accelerometry: descriptive analyses from the 22-year follow-up of the Pelotas 1993 birth cohort

OBJECTIVE

To describe the sleep time window (STW), total sleep time (TST), and sleep percent [SP = (TST/STW) × 100] by accelerometry in a population-based young adult cohort in Brazil.

METHODS

Cross-sectional analysis with a 22-year sample (N = 2462). Sleep variables were measured using an accelerometer. The devices were worn on the non-dominant wrist for approximately seven days. A raw data analysis using the GGIR package was performed. The following sleep variables were extracted: TST, STW, and SP. Linear regression was used to adjust averages. All analyses were stratified according to sex. A comparison between weekday and weekend averages was also conducted.

RESULTS

The means of TST, STW, and SP for men were 5.9 h, 7.1 h, and 83.1%, respectively. For women, the means of TST, STW, and SP were 6.4 h, 7.6 h, and 84.6%, respectively. Women presented a higher means of all outcomes compared to men (p < 0.001). After adjusting for both sexes, white skin color and not working or studying were associated with higher TST. Individuals not working or studying presented higher means of STW and lower sleep SP. Women with children who were less than two years of age presented lower values of three evaluated outcomes. Regarding behavior and health condition variables, obesity was associated with lower STW only for men. Physical activity was associated with higher SP and risk drinking with lower TST and STW only for women.

CONCLUSION

Differences between sexes were observed in TST, STW, and SP. In all outcomes women presented a higher means. Socioeconomic variables were associated with both sexes, but having children and behavior/health conditions differed between sexes.

Associations between sleep and obesity indices in older adults: results from the HELIAD study

BACKGROUND

Short sleep duration and low sleep quality are negatively associated with obesity in young adults, but in older people the results are inconsistent.

AIMS

The aim of the present study was to examine the associations between sleep duration and quality with both body mass index (BMI) and waist circumference (WC) and to investigate sex- and age-specific associations in a population-representative cohort of older adults.

METHODS

1781 participants ≥ 65 years old from the HELIAD study were included. Sleep duration and quality were based on self-report, whereas BMΙ and WC were evaluated clinically.

RESULTS

Sleep duration was inversely related to WC, only in women, even after adjustment for age, sex, years of education, total energy intake and level of physical activity. Furthermore, sleep quality was negatively related to both BMI and WC in women. In men, however, no significant relationships were observed between these variables. Associations between sleep and weight did not differ between those aged < 73 and ≥ 73 years old.

DISCUSSION

To the best of our knowledge, this is the first study examining both sleep duration and quality with BMI and WC in older adults, performing by-sex analysis. Although additional studies are needed, improvements in sleep habits should be considered in weight management of older individuals.

CONCLUSIONS

Our results suggest that poor sleep is associated to adverse weight effects in older women, but not men.

Information on Bedtimes and Wake Times Improves the Relation Between Self-Reported and Objective Assessments of Sleep in Adults

STUDY OBJECTIVES

To investigate the correlation between self-reported and objective measures of total sleep time (TST) in adults and examine whether sex, race/ethnicity, and weight status influence this association.

METHODS

Participants were individuals who screened for sleep intervention studies, providing > 7 days of wrist actigraphy sleep data (TSTobj) and reporting sleep duration (TSTPSQI) using the Pittsburgh Sleep Quality Index (PSQI) questionnaire (n = 53 men, 60 women; 59% minority/Hispanics; age 30.9 ± 9.7 years; body mass index 26.2 ± 3.2 kg/m2). In addition, TSTbed/wake was calculated as the difference between bedtime and waketime, minus the time to fall asleep, from the PSQI. Univariate regression analyses were performed to assess the relation between TSTobj and TSTPSQI and TSTbed/wake and compare the relation by sex, race, and ethnicity. Bland-Altman tests were done to assess bias by sex, race/ethnicity, weight status, and sleep quality.

RESULTS

TSTbed/wake correlated with TSTobj (r = .57, P < .0001). TSTPSQI and TSTbed/wake were greater than TSTobj (0.63 ± 0.99 hours and 0.79 ± 0.76 hours, respectively, both P < .0001). The difference between TSTPSQI and TSTobj did not vary by sex (β = .12, P = .52), race/ethnicity (β = .15, P = .48), age (β = -.01, P = .27), or body mass index (β = .04, P = .13) whereas that between TSTbed/wake and TSTobj varied by age (β = -.020, P = .0051), BMI (β = .054, P = .0021), race/ethnicity (β = .36, P = .021), and sleep efficiency (β = -.089, P < .0001).

CONCLUSIONS

Calculating TST using self-reported bedtimes and wake times provided TST estimate that correlated with TSTobj but greater over-reporting occurred in younger and heavier individuals, non-whites or Hispanics, and those with low sleep efficiency. In clinical and research settings, asking individuals to report bedtimes, wake times, and length of time to fall asleep may more accurately estimate TST than asking about sleep duration alone.

Associations of Sleep Characteristics With Cognitive Function and Decline Among Older Adults

Sleep laboratory studies find that restricted sleep duration leads to worse short-term cognition, especially memory. Observational studies find associations between self-reported sleep duration or quality and cognitive function. However self-reported sleep characteristics might not be highly accurate, and misreporting could relate to cognition. In the Sleep Study of the National Social Life, Health, and Aging Project (NSHAP), a nationally representative cohort of older US adults (2010-2015), we examined whether self-reported and actigraph-measured sleep are associated with cross-sectional cognitive function and 5-year cognitive decline. Cognition was measured with the survey adaptation of the multidimensional Montreal Cognitive Assessment (MoCA-SA). At baseline (n = 759), average MoCA-SA score was 14.1 (standard deviation, 3.6) points of a possible 20. In cross-sectional models, actigraphic sleep-disruption measures (wake after sleep onset, fragmentation, percentage sleep, and wake bouts) were associated with worse cognition. Sleep disruption measures were standardized, and estimates of association were similar (range, -0.37 to -0.59 MoCA-SA point per standard deviation of disruption). Actigraphic sleep-disruption measures were also associated with odds of 5-year cognitive decline (4 or more points), with wake after sleep onset having the strongest association (odds ratio = 1.43, 95% confidence interval: 1.04, 1.98). Longitudinal associations were generally stronger for men than for women. Self-reported sleep showed little association with cognitive function.

Assessing potential shared genetic aetiology between body mass index and sleep duration in 142,209 individuals

Observational studies find an association between increased body mass index (BMI) and short self-reported sleep duration in adults. However, the underlying biological mechanisms that underpin these associations are unclear. Recent findings from the UK Biobank suggest a weak genetic correlation between BMI and self-reported sleep duration. However, the potential shared genetic aetiology between these traits has not been examined using a comprehensive approach. To investigate this, we created a polygenic risk score (PRS) of BMI and examined its association with self-reported sleep duration in a combination of individual participant data and summary-level data, with a total sample size of 142,209 individuals. Although we observed a nonsignificant genetic correlation between BMI and sleep duration, using LD score regression (rg  = -0.067 [SE = 0.039], P = 0.092) we found that a PRS of BMI is associated with a decrease in sleep duration (unstandardized coefficient = -1.75 min [SE = 0.67], P = 6.13 × 10-7 ), but explained only 0.02% of the variance in sleep duration. Our findings suggest that BMI and self-reported sleep duration possess a small amount of shared genetic aetiology and other mechanisms must underpin these associations.

Sex and race differences in the association between sleep duration and adiposity: the Bogalusa Heart Study

BACKGROUND

Short sleep duration has been consistently associated with obesity. However, few studies in adults have assessed whether this association varies by sex and race.

METHODS

In the 2013-2016 examination of 1116 participants from the biracial Bogalusa Heart Study, habitual sleep duration was measured in categories (<6 hours, 6-7 hours, 7-8 hours, > 8 hours) using self-report. Anthropometry was performed and adiposity was assessed using body mass index (BMI) and waist circumference. Linear regression models estimated the relationship between sleep duration and adiposity adjusting for age, education, employment, bed partner status, depressive symptoms, smoking status, physical activity, and the use of alcohol and sleeping pills. Effect modification by sex and race was examined using cross-product terms in the models and marginal means were reported.

RESULTS

Of 1116 participants (mean age 48.2 years), 58.3% were female, and 31.7% were Black. In adjusted analyses, women sleeping <6 hours had a 3.2 (95% CI 1.4, 5.0) kg/m² greater BMI and 6.1 (1.8, 10.4) cm greater waist circumference compared to women sleeping 7-8 hours. In contrast, men had similar BMIs and waist circumferences regardless of sleep duration (p's for interaction = 0.04 & 0.11). There was no effect modification by race.

CONCLUSIONS

In this sample, lower habitual sleep duration was associated with greater adiposity among women compared to men. Further research is needed to understand the potential mechanisms of the adverse metabolic effects of short sleep in women.

Associations between polysomnography and actigraphy-based sleep indices and glycemic control among those with and without type 2 diabetes: the Multi-Ethnic Study of Atherosclerosis

Study Objectives

To examine the associations of sleep measures with hemoglobin A1c (HbA1c) among individuals with and without type 2 diabetes.

Methods

Data were from 2049 Multi-Ethnic Study of Atherosclerosis participants taking part in a sleep ancillary study. Cross-sectional linear regression models examined associations of actigraphy estimates of sleep (sleep duration, variability, and maintenance efficiency) and polysomnography measures (obstructive sleep apnea [OSA] and hypoxemia) with HbA1c, stratified by diabetes status. Primary models were adjusted for demographics, lifestyle behaviors, and obesity.

Results

Among individuals with diabetes (20 per cent population), those who slept <5 hr/night had greater HbA1c than those who slept 7-8 hr/night (7.44 vs. 6.98 per cent, ptrend = 0.04), with no attenuation of associations after adjusting for OSA/hypoxemia. In women with diabetes, but not men, those in the lowest quartile of sleep maintenance efficiency had greater HbA1c than those in the highest quartile of sleep maintenance efficiency (7.60 vs. 6.97 per cent, ptrend < 0.01). Among those without diabetes, individuals with severe OSA or in the highest quartile of hypoxemia had significantly greater HbA1c than those without OSA or who were in the lowest quartile of hypoxemia (5.76 vs. 5.66 per cent, ptrend = 0.01; 5.75 vs. 5.66 per cent, ptrend < 0.01, respectively). Associations did not meaningfully differ by race/ethnicity.

Conclusions

Among individuals with diabetes, HbA1c was significantly higher in men and women with short sleep duration and in women with poor sleep maintenance efficiency, suggesting a role for behavioral sleep interventions in the management of diabetes. Among individuals without diabetes, untreated severe OSA/hypoxemia may adversely influence HbA1c.

Gender-dependent association between sleep duration and overweight incidence in CHINESE school children: a national follow-up study

BACKGROUND

The relationship between sleep duration and overweight risk remains unexplored among Chinese children. This study aims to evaluate this association in a national investigation with school-aged population.

METHODS

There were 18,302 normal weight children in this Chinese national study which conducted during 2013-2014 included in the research. Anthropometric measurements were performed both at baseline and after 6-9 month. Sleep duration, physical activity, food intake and social economic information were collected by self-report questionnaire. Overweight was defined according to the updated Chinese criterion. Cox regression was used to evaluate the relationships between sleep duration and overweight incidence with multivariable adjusted.

RESULTS

In total, there were 443 new overweight cases recorded at the end of observation. Overweight incidence with greater than 9 h (long sleep duration, LSD), 7 to 9 h (middle sleep duration, MSD), and less than 7 h of sleep (short sleep duration, SSD) were 2.7, 3.1 and 3.3% respectively. Stratified by gender and compared with LSD, the hazard ratio (HR) of overweight for females with MSD was 1.60 (95% CI: 1.02-2.52). Stratified by age and gender, the HR in the group of MSD was 2.13 (1.20-3.77) in female aged 6-10 years and 0.24 (0.06-0.93) in female aged 15-17 years.

CONCLUSION

The association between short sleep duration and overweight is age- and gender dependent. In group of small age and elder age, girls' adiposity states are independently associated with sleep duration. Sleep recommendation is a potential preventive action for overweight/obesity among girls.

Weight gain in first-semester university students: Positive sleep and diet practices associated with protective effects

For university students, alterations in sleep and diet quality are common, and the propensity for weight gain is well established. The role of sleep duration during periods of rapid weight gain is understudied. This study explored the relationships between sleep duration, diet patterns, and body composition in first-year university students. Data collection occurred during the beginning of the fall (August) and spring semesters (January). Anthropometric measures included weight, height, and percent body fat (%BF). Survey questions assessed sleep and diet quality. As a group, participants (N = 60) gained weight (1.8 ± 2.1 kg) over the 4.5-month period of study. Hierarchical cluster analysis (HCA) identified three groups based on weight change between baseline and follow-up visits. Group 1 ("maintainers") (N = 21) gained 0.1 ± 1.3 kg, group 2 ("modest gainers") (N = 24) gained 2.0 ± 1.7 kg, and group 3 ("major gainers") (N = 15) gained 3.8 ± 1.8 kg. No differences in weight, body mass index (BMI), %BF, or average sleep duration existed between clusters at baseline. Minimal differences in baseline dietary behaviors between groups were noted other than maintainers used more fat, e.g., butter, to season vegetables, bread, and potatoes compared to modest gainers (p = .010). At follow-up, sleep duration significantly decreased from baseline among major gainers (7.1 ± 0.7 vs. 6.8 ± 0.7 h, p = .017) while sleep duration increased from baseline among maintainers (7.3 ± 0.9 vs. 7.6 ± 1.0 h, p = .048). Sleep duration at follow-up was significantly shorter among major gainers compared to maintainers (p = .016). Total diet scores for maintainers and modest gainers improved between visits (p = .038 and 0.002, respectively) but did not change among major gainers. Combining sleep and diet education may increase the effectiveness of interventions designed to mitigate weight gain in this high-risk population.

Persistence of social jetlag and sleep disruption in healthy young adults

Sleep disruption has been associated with increased risks for several major chronic diseases that develop over decades. Differences in sleep/wake timing between work and free days can result in the development of social jetlag (SJL), a chronic misalignment between a person's preferred sleep/wake schedule and sleep/wake timing imposed by his/her work schedule. Only a few studies have examined the persistence of SJL or sleep disruption over time. This prospective investigation examined SJL and sleep characteristics over a 2-year period to evaluate whether SJL or poor sleep were chronic conditions during the study period. SJL and sleep measures (total sleep time [TST], sleep onset latency [SOL], wake after sleep onset [WASO]), and sleep efficiency [SE]), were derived from armband monitoring among 390 healthy men and women 21-35 years old. Participants wore the armband for periods of 4-10 days at 6-month intervals during the follow-up period (N = 1431 repeated observations). The consistency of SJL or sleep disruption over time was analyzed using generalized linear mixed models (GLMMs) for repeated measures. Repeated measures latent class analysis (RMLCA) was then used to identify subgroups among the study participants with different sleep trajectories over time. Individuals in each latent group were compared using GLMMs to identify personal characteristics that differed among the latent groups. Minor changes in mean SJL, chronotype, or TST were observed over time, whereas no statistically significant changes in SOL, WASO, or SE were observed during the study period. The RMLCA identified two groups of SJL that remained consistent throughout the study (low SJL, mean ± SE: 0.4 ± 0.04 h, 42% of the study population; and high SJL, 1.4 ± 0.03 h, 58%). Those in the SJL group with higher values tended to be employed and have an evening chronotype. Similarly, two distinct subgroups were observed for SOL, WASO, and SE; one group with a pattern suggesting disrupted sleep over time, and another with a consistently normal sleep pattern. Analyses of TST identified three latent groups with relatively short (5.6 ± 1.0 h, 21%), intermediate (6.5 ± 1.0 h, 44%), and long (7.3 ± 1.0 h, 36%) sleep durations, all with temporally stable, linear trajectories. The results from this study suggest that sleep disturbances among young adults can persist over a 2 year period. Latent groups with poor sleep tended to be male, African American, lower income, and have an evening chronotype relative to those with more normal sleep characteristics. Characterizing the persistence of sleep disruption over time and its contributing factors could be important for understanding the role of poor sleep as a chronic disease risk factor.

Role of Sex and the Environment in Moderating Weight Gain Due to Inadequate Sleep

PURPOSE OF REVIEW

The growing prevalence of obesity, inadequate sleep and sleep disorders together with the negative impact of lack of sleep on overall health highlights the need for therapies targeted towards weight gain due to sleep loss.

RECENT FINDINGS

Sex disparities in obesity and sleep disorders are present; yet, the role of sex is inadequately addressed and thus it is unclear whether sensitivity to sleep disruption differs between men and women. Like sex, environmental factors contribute to the development of obesity and poor sleep. The obesogenic environment is characterized by easy access to palatable foods and a low demand for energy expenditure in daily activities. These and other environmental factors are discussed, as they drive altered sleep or their interaction with food choice and intake can promote obesity. We discuss data that suggest differences in sleep patterns and responses to sleep disruption influence sex disparities in weight gain, and that enviromental disturbances alter sleep and interact with features of the obesogenic environment that together promote obesity.

Sex-specific associations of different anthropometric indices with acute and chronic insomnia

Background

Sleep disorders, including insomnia, are risk factors for weight gain. However, few epidemiological studies have investigated the association of anthropometric markers with insomnia as an outcome.

Methods

In this observational, cross-sectional study, we assessed the association of 3 different anthropometric indices with acute and chronic insomnia. We used data from 13 389 French adults (mean age= 51.9 ± 13.1 years; 70.3% women) enrolled in the NutriNet-Santé-Biobank cohort. Body weight, height, waist and hip circumference were measured once during a clinic visit (2011-14). Body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) were the main predictors. Acute (past 8 days) and chronic (≥3 months) insomnia were assessed in 2014 via a self-report questionnaire. We fit multivariable logistic regression models providing odds ratios (OR) and 95% confidence intervals (CI).

Results

Overweight (25.0 ≤ BMI < 30.0 kg/m2) and general obesity (BMI ≥ 30.0 kg/m2) appeared to have an inverse association with acute insomnia only among men (overweight: OR= 0.80, 95% CI: 0.70, 0.92; obesity: OR= 0.78, 95% CI: 0.63, 0.98). Obesity assessed by BMI and WHR appeared to be positively associated with chronic insomnia only among women (BMI: OR= 1.23, 95% CI: 1.04, 1.45; WHR: OR= 2.24, 95% CI: 1.07, 4.72). WC did not display any significant associations in either sex.

Conclusions

These cross-sectional results revealed sex-specific associations of overweight/obesity with different types of insomnia, and merit confirmation longitudinally with objectively assessed sleep parameters. Nonetheless, the findings reinforce the critical importance of joint health behaviour promotion.

Sleep and dietary habits in the urban environment: the role of chrono-nutrition

The urban environment has changed vastly over past decades, which also has had an impact on our sleep and dietary patterns and possibly health outcomes. Some studies have shown that sleep duration and sleep quality has declined over past decades, especially in children. In parallel, our lifestyle and dietary patterns have also changed including more shift work, more meals outside the home or family setting and more irregular eating patterns, including breakfast skipping and late-night eating. This new area of research in nutritional sciences studying the impact of the timing of eating on health outcomes is called chrono-nutrition, and combines elements from nutritional research with chrono-biology. The objectives of this paper were to discuss secular trends in sleep patterns and related dietary patterns, introduce basic concepts and mechanisms of chrono-nutrition and discuss the evidence for the importance of sleep and chrono-nutrition in relation to health outcomes. Overall, chrono-nutrition could mediate the effects between sleep, diet and urbanisation, and more research is needed to elucidate the importance of chrono-nutrition for metabolic health and its impact on public health.

Habitual sleep as a contributor to racial differences in cardiometabolic risk

Insufficient and disrupted sleep is linked with cardiovascular and metabolic dysregulation and morbidity. The current study examines the degree to which differences in sleep between black/African American (AA) and white/European American (EA) adults explain racial differences in cardiometabolic (CMB) disease risk. Total sleep time and sleep efficiency (percent of time in bed asleep) were assessed via seven nights of wrist actigraphy among 426 participants in the Midlife in the United States Study (31% AA; 69% EA; 61% female; mean age = 56.8 y). CMB risk was indexed as a composite of seven biomarkers [blood pressure, waist circumference, hemoglobin A1c (HbA1c), insulin resistance, triglycerides, HDL cholesterol (HDL-C), and C-reactive protein]. Covariates included sociodemographic characteristics and relevant health behaviors. Results indicated that AAs relative to EAs obtained less sleep (341 vs. 381 min) and had lower sleep efficiency (72.3 vs. 82.2%) (P values < 0.001). Further, 41% and 58% of the racial difference in CMB risk was explained by sleep time and sleep efficiency, respectively. In models stratified by sex, race was indirectly associated with CMB risk via sleep time and efficiency only among females (explaining 33% and 65% of the race difference, respectively). Indirect effects were robust to alternative model specifications that excluded participants with diabetes or heart disease. Consideration of sleep determinants and sleep health is therefore needed in efforts to reduce racial differences in CMB disease.

The epidemiology of sleep and obesity

Sleep is a state of consciousness that is preserved across animal species whose exact function is not yet clear but which has a vital impact on health and well-being. Epidemiological evidence suggests sleep duration in both children and adults has been decreasing over the past half-century, while at the same time rates of overweight and obesity have been increasing. Short sleep duration along with other dimensions of poor sleep has been associated with obesity both cross-sectionally and longitudinally. These data suggest a potential causal relationship between poor sleep and greater rates of weight gain that may be related to effects of sleep on dietary intake or physical activity. However, there is also potential for reverse causation as obesity leads to many co-morbidities including sleep apnea that can disrupt sleep. Medium and long term interventional studies are needed to evaluate the potential for healthy sleep interventions to help combat the epidemic of obesity.

Does one size fit all? The role of body mass index and waist circumference in systemic inflammation in midlife by race and gender

OBJECTIVE

This study investigates the associations of body mass index (BMI) and waist circumference (WC) with markers of systemic inflammation in midlife by race and gender.

DESIGN

Data were obtained from the Survey of Midlife in the United States, a cross-sectional, observational study of Americans 35 years old or older (White men: N = 410; White women: N = 490; Black men: N = 58; Black women: N = 117). Inflammation was measured by concentrations of fibrinogen and C-reactive protein (CRP) in fasting plasma and concentrations of E-selectin and interleukin-6 (IL-6) in fasting serum. Anthropometric data were used to obtain BMI and WC. Socio-demographic and health-related factors were assessed with a survey. Multivariate models by race and gender were estimated to test the roles of BMI and WC for each inflammation marker.

RESULTS

Compared to White men, Black women have higher BMI and higher levels of all four inflammation markers; White women have lower BMI, lower WC, and lower E-selectin and fibrinogen but higher CRP; and Black men have higher fibrinogen. After adjusting for socio-demographic and health-related covariates as well as perceived discrimination, WC is associated with all four markers of inflammation among White men and women; with three markers (fibrinogen, CRP, and IL-6) of inflammation among Black women; and with CRP (and marginally with fibrinogen and E-selectin) among Black men. BMI is associated with higher CRP and fibrinogen among Black men (marginally so for White men) but not for women of either race.

CONCLUSIONS

WC shows more consistent associations with inflammation markers than BMI, although the relationships vary by inflammation marker and population group. Our findings suggest that WC is a risk factor for systemic inflammation among White and Black men and women, and BMI is an additional risk factor for Black men.

Investigating the Bidirectional Associations of Adiposity with Sleep Duration in Older Adults: The English Longitudinal Study of Ageing (ELSA)

Cross-sectional analyses of adiposity and sleep duration in younger adults suggest that increased adiposity is associated with shorter sleep. Prospective studies have yielded mixed findings, and the direction of this association in older adults is unclear. We examined the cross-sectional and potential bi-directional, prospective associations between adiposity and sleep duration (covariates included demographics, health behaviours, and health problems) in 5,015 respondents from the English Longitudinal Study of Ageing (ELSA), at baseline and follow-up. Following adjustment for covariates, we observed no significant cross-sectional relationship between body mass index (BMI) and sleep duration [(unstandardized) B = −0.28 minutes, (95% Confidence Intervals (CI) = −0.012; 0.002), p = 0.190], or waist circumference (WC) and sleep duration [(unstandardized) B = −0.10 minutes, (95% CI = −0.004; 0.001), p = 0.270]. Prospectively, both baseline BMI [B = −0.42 minutes, (95% CI = −0.013; −0.002), p = 0.013] and WC [B = −0.18 minutes, (95% CI = −0.005; −0.000), p = 0.016] were associated with decreased sleep duration at follow-up, independently of covariates. There was, however, no association between baseline sleep duration and change in BMI or WC (p > 0.05). In older adults, our findings suggested that greater adiposity is associated with decreases in sleep duration over time; however the effect was very small.

Racial disparities in sleep: the role of neighborhood disadvantage

OBJECTIVE

Disparities in sleep duration and efficiency between Black/African American (AA) and White/European American (EA) adults are well-documented. The objective of this study was to examine neighborhood disadvantage as an explanation for race differences in objectively measured sleep.

METHODS

Data were from 133 AA and 293 EA adults who participated in the sleep assessment protocol of the Midlife in the United States (MIDUS) study (57% female; Mean Age = 56.8 years, SD = 11.4). Sleep minutes, onset latency, and waking after sleep onset (WASO) were assessed over seven nights using wrist actigraphy. Neighborhood characteristics were assessed by linking home addresses to tract-level socioeconomic data from the 2000 US Census. Multilevel models estimated associations between neighborhood disadvantage and sleep, and the degree to which neighborhood disadvantage mediated race differences in sleep controlling for family socioeconomic position and demographic variables.

RESULTS

AAs had shorter sleep duration, greater onset latency, and higher WASO than EAs (ps < 0.001). Neighborhood disadvantage was significantly associated with WASO (B = 3.54, p = 0.028), but not sleep minutes (B = -2.21, p = 0.60) or latency (B = 1.55, p = 0.38). Furthermore, race was indirectly associated with WASO via neighborhood disadvantage (B = 4.63, p = 0.035), which explained 24% of the race difference. When measures of depression, health behaviors, and obesity were added to the model, the association between neighborhood disadvantage and WASO was attenuated by 11% but remained significant.

CONCLUSION

Findings suggest that neighborhood disadvantage mediates a portion of race differences in WASO, an important indicator of sleep efficiency.

Actigraphy Measured Sleep Indices and Adiposity: The Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

To investigate the cross-sectional relationship between objectively measured sleep characteristics and multiple indices of adiposity in racially/ethnically diverse older adults within the MESA Sleep study (n = 2,146).

METHODS

7-day actigraphy was used to assess sleep duration, sleep efficiency, and night-to-night variability. Body mass index (BMI), waist circumference, and total body fat were modeled continuously and according to obesity cut-points. Models were adjusted for demographic, socioeconomic, and behavioral variables.

RESULTS

Participants who slept less than 6 hours a night had significantly higher BMI, waist circumference, and body fat relative to those who slept 7-8 hours. Those who slept less than 5 hours had a 16% higher prevalence of general obesity (BMI ≥ 30 vs. < 25 kg/m(2)) (95% [CI]: 0.08-0.24) and a 9% higher prevalence of abdominal obesity (waist circumference: women ≥ 88 centimeters, men ≥ 102 centimeters; 95% CI: 0.03-0.16) compared to those who slept 7-8 hours. Results were similar for sleep efficiency and night-to-night sleep variability.

CONCLUSIONS

Among an older multi-ethnic cohort, we found robust associations across multiple indices of sleep and adiposity. Targeting sleep characteristics may be of benefit in obesity interventions, but more research is needed to rule out reverse causality.

Association between nighttime sleep and successful aging among older Chinese people

OBJECTIVE

This study aims to assess the association between sleep and successful aging among Chinese ≥60 years of age.

METHODS

Data were collected from the baseline survey of the China Health and Retirement Longitudinal Study. Two self-reported questions about sleep quality and duration were examined. Successful aging was defined following Rowe and Kahn's multidimensional model. To assess the adjusted association between sleep and successful aging, multivariable logistic regression was applied.

RESULTS

The average number of self-reported hours of sleep was 6.2 ± 2.0 among older Chinese people. Successful aging was related to sleep duration, with the proportion of those adults considered to be aging successfully falling into the following sleep duration categories (<6 h - 7.8%; 6 h - 16.3%; 7 h - 19.1%; 8 h - 14.7%; and ≥9 h - 12.8%). The plots between sleep duration and successful aging were an inverse U-shape. Participants who slept less than 6 h per day had lower odds ratios of successful aging [odds ratio (OR) = 0.52, 95% confidence interval (CI) 0.40-0.67] relative to those who slept for 7 h per day. Compared with those who reported poor sleep less than once a week, older people who reported poor sleep five to seven days a week showed a lower ratio of successful aging (OR = 0.29, 95% CI 0.21-0.39).

CONCLUSION

Older age, shorter or longer sleep, and poor sleep were related to lower odds of, rates of successful aging. Most older Chinese adults experience insufficient sleep and poor sleep quality, which could be an important influential factor in successful aging.

Time to wake up: No impact of COMT Val158Met gene variation on circadian preferences, arousal regulation and sleep

Dopamine has been implicated in the regulation of sleep-wake states and the circadian rhythm. However, there is no consensus on the impact of two established dopaminergic gene variants: the catechol-O-methyltransferase Val158Met (COMT Val158Met; rs4680) and the dopamine D4 receptor Exon III variable-number-of-tandem-repeat polymorphism (DRD4 VNTR). Pursuing a multi-method approach, we examined their potential effects on circadian preferences, arousal regulation and sleep. Subjects underwent a 7-day actigraphy assessment (SenseWear Pro3), a 20-minute resting EEG (analyzed using VIGALL 2.0) and a body mass index (BMI) assessment. Further, they completed the Morningness-Eveningness Questionnaire (MEQ), the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). The sample comprised 4625 subjects (19-82 years) genotyped for COMT Val158Met, and 689 elderly subjects (64-82 years) genotyped for DRD4 VNTR. The number of subjects varied across phenotypes. Power calculations revealed a minimum required phenotypic variance explained by genotype ranging between 0.5% and 1.5% for COMT Val158Met and between 3.3% and 6.0% for DRD4 VNTR. Analyses did not reveal significant genotype effects on MEQ, ESS, PSQI, BMI, actigraphy and EEG variables. Additionally, we found no compelling evidence in sex- and age-stratified subsamples. Few associations surpassed the threshold of nominal significance (p < .05), providing some indication for a link between DRD4 VNTR and daytime sleepiness. Taken together, in light of the statistical power obtained in the present study, our data particularly suggest no impact of the COMT Val158Met polymorphism on circadian preferences, arousal regulation and sleep. The suggestive link between DRD4 VNTR and daytime sleepiness, on the other hand, might be worth investigation in a sample enriched with younger adults.

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.

Relationship between actigraphy-assessed sleep quality and fat mass in college students

OBJECTIVE

Only a few studies have used objective measurements to investigate the relationship between sleep quality and obesity. These studies showed controversial results.

METHODS

Sleep efficiency was measured by Actiwatch 2 in 132 healthy students (age 23.3 ± 3.7 years, BMI 23.1 ± 4.1 kg/m(2) ) for 12 ± 3 nights, differentiating between work and free days. Physical activity, dietary habits, and autonomic function (heart rate variability, HRV) were analyzed as potential determinants of sleep quality and its relationship with body composition.

RESULTS

Sleep efficiency was 87.0% in women and 84.9% in men (P < 0.05) and was higher at free days when compared to work days in women (P < 0.05). Lower sleep efficiency was associated with a higher fat mass. This was true for sleep efficiency on work days in women [fat mass index (FMI): r = -0.35, P < 0.01] and for free days in men (FMI: r = -0.37, P < 0.05). Poor sleep efficiency was associated with less physical activity (r = 0.29, P < 0.05) and impaired HRV in women (r = 0.60, P < 0.05) and with a higher fat intake in men (r = -0.39, P < 0.05).

CONCLUSIONS

Poor sleep efficiency was associated with higher fat mass. The relationship between sleep quality and fat mass differs between work and free days and may be explained by physical activity and autonomic function in women and dietary habits in men.

Sleep duration and health among older adults: associations vary by how sleep is measured

BACKGROUND

Cohort studies have found that short and long sleep are both associated with worse outcomes, compared with intermediate sleep times. While demonstrated biological mechanisms could explain health effects for short sleep, long-sleep risk is puzzling. Most studies reporting the U shape use a single question about sleep duration, a measurement method that does not correlate highly with objectively measured sleep. We hypothesised that the U shape, especially the poor outcomes for long sleepers, may be an artefact of how sleep is measured.

METHODS

We examined the cross-sectional prevalence of fair/poor health by sleep hour categories (≤ 6, ≤ 7, ≤ 8, ≤ 9, > 9 h) in a national US sample of adults aged 62-90 that included several types of sleep measures (n = 727). Survey measures were: a single question; usual bedtimes and waking times; and a 3-day sleep log. Actigraphy measures were the sleep interval and total sleep time. Fair/poor health was regressed on sleep hour categories adjusted for demographics, with tests for both linear trend and U shape.

RESULTS

Adjusted OR of fair/poor health across sleep hour categories from the single question were 4.6, 2.2, referent (8 h), 1.8 and 6.9. There was high prevalence of fair/poor health for ≤ 6 h for all sleep measures, but the long-sleep effect was absent for sleep logs and actigraphy measures.

CONCLUSIONS

Associations between long sleep and poor health may be specific to studies measuring sleep with survey questions. As cohorts with actigraphy mature, our understanding of how sleep affects health may change.

Successful physical exercise-induced weight loss is modulated by habitual sleep duration in the elderly: results of a pilot study

Although it is widely accepted that physical exercise promotes weight loss, physical exercise alone had been found to result in only marginal weight loss compared to no treatment. Interestingly, both subjective and objective sleep duration have been shown to be negatively correlated to the body mass index (BMI). Despite this growing evidence of a relation between sleep duration and body weight, the role of habitual sleep duration in physical exercise-induced weight loss has not been studied so far. Twenty-two healthy elderly good sleepers aged 61-76 years (mean 68.36 years, 55 % female, BMI mean 25.15 kg/m²) either took part in a 12-week aerobic endurance training (3 × 30 min/week) or in a relaxation control (2 × 45 min/week). The BMI was assessed prior to and after intervention. Subjects maintained sleep logs every morning/evening during the training period, allowing for calculation of habitual sleep duration. Besides a significant main effect of the type of training, a significant interaction of type of training and habitual sleep duration was observed: while after treadmill training subjects who slept less than 7.5 h/night during intervention reduced their BMI by nearly 4 %, a comparable decrease in the BMI was found neither in subjects who slept more than 7.5 h nor after relaxation training independent of sleep duration. Sleep duration itself did not change in any group. Although results should be interpreted with caution due to the small sample size, this is the first study to indicate that physical exercise might compensate for disturbed body weight regulation associated with short sleep duration.

Association between sleep duration and obesity is modified by dietary macronutrients intake in Korean

BACKGROUND

Short sleep duration has been reported to be inversely associated with risk of obesity.

METHODS

The effects of sleep duration on obesity-related variables and the interaction of sleep duration and dietary macronutrients consumption on risk of obesity were analysed in 14,111 subjects aged 20-79 from the Korean National Health and Nutrition Examination Survey.

RESULTS

Sleep restriction to less than 7h per day resulted in higher body mass index, plasma triglyceride level, and obesity prevalence for women, but not for men. Protein intake was significantly lower in subjects with lower sleep duration for both men and women. The subjects with short sleep duration were significantly higher fat consumption for men, whereas carbohydrate consumption for women. Among subjects whose carbohydrate consumption was above the median, subjects with sleep duration of less than 7h per day increased their odds of being obese (OR=1.255, 95% CI: 1.073-1.476, P<0.001) compared to subjects with sleep duration more than 7h per day for women.

CONCLUSIONS

Our results showed that sleep duration positively correlated with protein consumption, but negatively correlated with carbohydrate consumption, which might lead to high risk of obesity for women. Also, our findings support a significant association between sleep duration and obesity-related variables and this association has been potentially modified by dietary macronutrients consumption in women subjects.

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.