Association between habitual sleep duration and blood pressure and clinical implications: a systematic review

Poor sleep and shift work associate with increased blood pressure and inflammation in UK Biobank participants

Disrupted circadian rhythms have been linked to an increased risk of hypertension and cardiovascular disease. However, many studies show inconsistent findings and are not sufficiently powered for targeted subgroup analyses. Using the UK Biobank cohort, we evaluate the association between circadian rhythm-disrupting behaviours, blood pressure (SBP, DBP) and inflammatory markers in >350,000 adults with European white British ancestry. The independent U-shaped relationship between sleep length and SBP/DBP is most prominent with a low inflammatory status. Poor sleep quality and permanent night shift work are also positively associated with SBP/DBP. Although fully adjusting for BMI in the linear regression model attenuated effect sizes, these associations remain significant. Two-sample Mendelian Randomisation (MR) analyses support a potential causal effect of long sleep, short sleep, chronotype, daytime napping and sleep duration on SBP/DBP. Thus, in the current study, we present a positive association between circadian rhythm-disrupting behaviours and SBP/DBP regulation in males and females that is largely independent of age.

Association between self-reported sleep duration and cardiometabolic risk in corporate executives

PURPOSE

This cross-sectional study aimed to compare the association between self-reported sleep duration and cardiometabolic risk among men and women corporate executives and investigate potential lifestyle, work- and stress-related mediators thereof.

METHODS

Self-reported sleep duration and lifestyle, occupational, psychological and measured anthropometrical, blood pressure (BP) and blood marker variables were obtained from health risk assessment data of 3583 corporate executives. Sex-stratified regression analyses investigated the relationships between occupational and psychological variables with self-reported sleep duration, and sleep duration with individual cardiometabolic risk factors. Mediation analyses investigated the effects of work, psychological and lifestyle factors on the relationships between self-reported sleep duration and cardiometabolic risk factors, as well as a continuous cardiometabolic risk score calculated from the sum of sex-stratified z-standardized scores of negative fasting serum HDL, and positive plasma Glu, serum TG, body mass index (BMI), waist circumference, systolic and diastolic BP.

RESULTS

Longer work hours and work commute time, depression, anxiety and stress were associated with shorter sleep duration in both men and women (all p < 0.05). Shorter sleep duration was associated with higher BMI, larger waist circumference and greater cardiometabolic risk scores in both men and women (all p < 0.05), higher diastolic BP in men (p < 0.05) and lower HDL cholesterol in women (p < 0.05). Physical activity, working hours and stress significantly mediated the relationships between self-reported sleep duration and BMI, waist circumference, diastolic BP and cardiometabolic risk score in men only.

CONCLUSION

In these corporate executives, shorter self-reported sleep duration is associated with poorer psychological, occupational and cardiometabolic risk outcomes in both men and women. Given that physical activity, working hours and stress mediate this association among the men, the case for sleep health interventions in workplace health programmes is warranted.

Sleep and cardiometabolic risk: a cluster analysis of actigraphy-derived sleep profiles in adults and children

STUDY OBJECTIVES

Sleep plays an important role in cardiometabolic health. Although the importance of considering sleep as a multidimensional construct is widely appreciated, studies have largely focused on individual sleep characteristics. The association between actigraphy-derived sleep profiles and cardiometabolic health in healthy adults and children has not been examined.

METHODS

This study used actigraphy-measured sleep data collected between February 2015 and March 2016 in the Child Health CheckPoint study. Participants wore actigraphy monitors (GENEActiv Original, Cambs, UK) on their nondominant wrist for 7 days and sleep characteristics (period, efficiency, timing, and variability) were derived from raw actigraphy data. Actigraphy-derived sleep profiles of 1,043 Australian children aged 11-12 years and 1,337 adults were determined using K-means cluster analysis. The association between cluster membership and biomarkers of cardiometabolic health (blood pressure, body mass index, apolipoproteins, glycoprotein acetyls, composite metabolic syndrome severity score) were assessed using Generalized Estimating Equations, adjusting for geographic clustering, with sex, socioeconomic status, maturity stage (age for adults, pubertal status for children), and season of data collection as covariates.

RESULTS

Four actigraphy-derived sleep profiles were identified in both children and adults: short sleepers, late to bed, long sleepers, and overall good sleepers. The overall good sleeper pattern (characterized by adequate sleep period time, high efficiency, early bedtime, and low day-to-day variability) was associated with better cardiometabolic health in the majority of comparisons (80%).

CONCLUSION

Actigraphy-derived sleep profiles are associated with cardiometabolic health in adults and children. The overall good sleeper pattern is associated with more favorable cardiometabolic health.

The association of insomnia disorder characterised by objective short sleep duration with hypertension, diabetes and body mass index: A systematic review and meta-analysis

Insomnia disorder with objective short sleep duration (less than 6 h of objective sleep or sleep efficiency less than 85%) has been considered as a biologically severe subtype of insomnia associated with a higher risk of cardiometabolic disease morbidity. This systematic review and meta-analysis firstly compared insomnia disorder with objective short and normal sleep duration, and subsequently, objective short sleep duration with and without insomnia disorder, and their associations with hypertension, type 2 diabetes and body mass index. A systematic search of five databases yielded 2345 non-duplicated articles, of which 11 individual studies were used for the qualitative review and 10 individual studies for the meta-analysis. The sample size varied from 30 to 4994 participants. A higher risk of hypertension (RR 1.54, 95% CI: [1.30; 1.82] p < 0.0001) and type 2 diabetes (RR 1.63 [1.37; 1.94], p < 0.0001) was associated with insomnia disorder with objective short sleep compared to normal sleep duration, but not for body mass index. Comparisons between insomnia disorder with objective short sleep and objective short sleep without insomnia disorder showed no significant differences. However, the majority of these studies were cross-sectional, and there is a need for more cohort study data.

Childhood sleep duration modifies the polygenic risk for obesity in youth through leptin pathway: the Beijing Child and Adolescent Metabolic Syndrome cohort study

BACKGROUND/OBJECTIVES

Short sleep is an obesity risk factor, however, little is known about its interplay with genetic predisposition and pathways involved in obesity pathogenesis, especially in the longitudinal setting. We aimed to investigate a possible sleep-gene interaction for childhood obesity risk, and whether the interaction in childhood longitudinally contributes to obesity risk at a 10-year follow-up and further to test if there is any mediation through the leptin pathway.

SUBJECTS/METHODS

A total of 3211 children from China (6-18 years) at baseline and 848 participants at 10-year follow-up from the Beijing Child and Adolescent Metabolic Syndrome (BCAMS) cohort study were analyzed. Baseline leptin concentrations and 12 established adult body mass index (BMI) loci were examined for the associations with habitual sleep duration.

RESULTS

After adjusting for covariates, including pubertal stages and behavioral factors, short sleep duration at baseline was significantly associated with increased overweight/obesity risk at both baseline and follow-up. Genetic predisposition scores (GPS), particularly consisting of leptin-related SNPs (GPSleptin), were robustly associated with baseline overweight/obesity in children who slept ≤8 h/day (P < 0.001), whereas the association was ablated in those who slept ≥10 h/day (P > 0.05). Comparable observations were made at follow-up. Mediation analysis revealed a modest direct effect of the GPSleptin-sleep interaction on BMI at baseline, while a significant indirect effect of this interaction was found to be mediated principally through elevated leptin (proportion: 52.6%); moreover, the mediation effect via leptin remained stable over 10 years.

CONCLUSIONS

This study suggests that shorter sleep duration in children from China (< 8h/day), compared to longer sleep duration (≥10 h/day), has a long-term impact on the association of polygenic risk for obesity from childhood to young adulthood and leptin pathway explains a key mechanism via a modification effect. Therefore, adequate sleep duration during childhood is important for the early prevention of obesity, especially if there is a genetic predisposition to this trait.

Sleep Duration and Blood Pressure: Recent Advances and Future Directions

PURPOSE OF REVIEW

This review discusses the recent literature on subjectively and objectively assessed sleep duration in relation to hypertension risk and out-of-clinic blood pressure (BP) measures and highlights critical areas for future research.

RECENT FINDINGS

Sleep duration, particularly short sleep, may influence BP through disturbed autonomic balance, hormonal imbalances, increased adiposity and metabolic dysfunction, and disrupted circadian rhythms. Observational studies indicate that short and long sleep are associated with hypertension risk, reduced nocturnal dipping, and elevated morning BP, but evidence is stronger for short sleep. Experimental sleep restriction increases BP, while sleep extension may lower BP in prehypertensive individuals. Women and racial/ethnic minorities are more prone to the detrimental effects of short sleep on BP. Additional studies are warranted to clarify the association of objectively assessed sleep with BP level and diurnal pattern and to determine the sex- and race-specific effects of sleep restriction and extension on BP.

Exosome and Macrophage Crosstalk in Sleep-Disordered Breathing-Induced Metabolic Dysfunction

Obstructive sleep apnea (OSA) is a highly prevalent worldwide public health problem that is characterized by repetitive upper airway collapse leading to intermittent hypoxia, pronounced negative intrathoracic pressures, and recurrent arousals resulting in sleep fragmentation. Obesity is a major risk factor of OSA and both of these two closely intertwined conditions result in increased sympathetic activity, oxidative stress, and chronic low-grade inflammation, which ultimately contribute, among other morbidities, to metabolic dysfunction, as reflected by visceral white adipose tissue (VWAT) insulin resistance (IR). Circulating extracellular vesicles (EVs), including exosomes, are released by most cell types and their cargos vary greatly and reflect underlying changes in cellular homeostasis. Thus, exosomes can provide insights into how cells and systems cope with physiological perturbations by virtue of the identity and abundance of miRNAs, mRNAs, proteins, and lipids that are packaged in the EVs cargo, and are secreted from the cells into bodily fluids under normal as well as diseased states. Accordingly, exosomes represent a novel pathway via which a cohort of biomolecules can travel long distances and result in the modulation of gene expression in selected and targeted recipient cells. For example, exosomes secreted from macrophages play a critical role in innate immunity and also initiate the adaptive immune response within specific metabolic tissues such as VWAT. Under normal conditions, phagocyte-derived exosomes represent a large portion of circulating EVs in blood, and carry a protective signature against IR that is altered when secreting cells are exposed to altered physiological conditions such as those elicited by OSA, leading to emergence of IR within VWAT compartment. Consequently, increased understanding of exosome biogenesis and biology should lead to development of new diagnostic biomarker assays and personalized therapeutic approaches. Here, the evidence on the major biological functions of macrophages and exosomes as pathophysiological effectors of OSA-induced metabolic dysfunction is discussed.

Impact of Sleep Duration and Weekend Oversleep on Body Weight and Blood Pressure in Adolescents

Introduction

Weekend oversleep or catchup sleep is a frequent occurrence in children, but there are relatively little data concerning its impact on weight and blood pressure. The aim of this study was to assess the association between sleep duration and oversleep, and weight and blood pressure in adolescents.

Methods

Sleep duration, weight and blood pressure of 327 children (51.4% boys, mean age 13.3 ± 1.7 years) who had polysomnograms performed during both exam cycles of the Tucson Children's Assessment of Sleep Apnea study (TuCASA) were analyzed. Sleep duration on school nights and non-school nights was used to compute a weighted average of child and parent reported overall sleep duration respectively. Oversleep was defined as the difference between self and parent reported weekend sleep and weekday sleep separately. Simple correlations between overall sleep duration, sleep on school and non-school nights and oversleep, and blood pressure, standardized body mass index (BMI), snoring, respiratory disturbance index (RDI) and age were calculated. Significant bivariate associations then were used to develop multivariate partial correlation models.

Results

Unadjusted negative correlations with BMI were noted for parent reported total sleep duration at the 1^st exam cycle, parent and child reported total sleep and school night sleep duration, and parent reported non-school night sleep duration at the 2^nd exam cycle. Additionally, for BMI, positive correlations were observed for log RDI at both exam cycles and snoring at the 2^nd exam cycle. For blood pressure, there were positive associations with age, parent reported oversleep, caffeine consumption and snoring. Additionally, for blood pressure, negative relationships were observed with parent reported total sleep duration at the 1^st exam cycle, and parent and child reported total sleep and school night sleep durations at the 2^nd exam cycle. Partial correlations found that BMI was negatively correlated with parent reported total sleep duration at the 1^st exam cycle and parent reported total sleep duration at the 2^nd exam cycle, and positively correlated with snoring and log RDI at both exam cycles. Systolic blood pressure was only associated with age and snoring. Diastolic blood pressure was positively correlated with age and caffeine consumption, and negatively correlated with parent reported total and school night sleep duration. Oversleep and child reported sleep duration were not represented in any of these models.

Conclusion

Lower amounts of sleep especially on school nights is associated with higher body weight and blood pressure. Oversleep was not associated with either body weight or blood pressure.

Morning surge in blood pressure and sympathetic activity in Mongolians and Han Chinese: a multimodality investigation of hypertension and dyssomnia

Background

Hypertension and dyssomnia are increasing significantly in Mongolians, and the related factors of ethnic differences in hypertension and dyssomnia between Mongolians and Han Chinese are unclear. This study examined the relationship of morning surge in blood pressure (MBP) with ethnicity, sleep situation, and sympathetic activity throughout the day.

Methods

Of 692 hypertensive patients screened, 202 subjects with dyssomnia were selected. They were then divided into Mongolian (n = 87) and Han (n = 115) groups. The differences in dyssomnia, 24-h blood pressure, and urinary catecholamine were analyzed in all subjects; they were then further divided according to the degree of dyssomnia (low, moderate, and severe) to determine the differences in blood pressure and catecholamine.

Results

Mongolians had a lower history of smoking, daytime dysfunction, nocturnal heart rates, and dopamine levels, but their body mass index, triglyceride, fasting glucose, morning surge in systolic blood pressure (MSBP), nocturnal systolic blood pressure (NSBP), nocturnal diastolic blood pressure, daytime systolic blood pressure, daytime heart rates, and dopamine level (D-DA) were higher than those of Han Chinese. With the aggravation of dyssomnia, MSBP, NSBP, D-NE, daytime epinephrine, and D-DA of Mongolians and Han Chinese increased gradually, but the rate of increase was faster in the latter (p < 0.05). D-DA was entered into the MSBP regression model of Mongolians (intercept, 157 mmHg), whereas D-DA and D-NE were entered into the MSBP regression model of Han Chinese (intercept, 142 mmHg).

Conclusion

Worsened dyssomnia induces higher MSBP and augments sympathetic excitability in Mongolians and Han Chinese. Mongolians with hypertension and dyssomnia had higher MSBP baseline and D-DA but lower N-DA. With an increase in D-DA, MSBP in Han and Mongolian patients increased gradually.

Association between sleep difficulties as well as duration and hypertension: is BMI a mediator?

Sleep difficulties and short sleep duration have been associated with hypertension. Though body mass index (BMI) may be a mediator variable, the mediation effect has not been defined. We aimed to assess the association between sleep duration and sleep difficulties with hypertension, to determine if BMI is a mediator variable, and to quantify the mediation effect. We conducted a mediation analysis and calculated prevalence ratios with 95% confidence intervals. The exposure variables were sleep duration and sleep difficulties, and the outcome was hypertension. Sleep difficulties were statistically significantly associated with a 43% higher prevalence of hypertension in multivariable analyses; results were not statistically significant for sleep duration. In these analyses, and in sex-specific subgroup analyses, we found no strong evidence that BMI mediated the association between sleep indices and risk of hypertension. Our findings suggest that BMI does not appear to mediate the association between sleep patterns and hypertension. These results highlight the need to further study the mechanisms underlying the relationship between sleep patterns and cardiovascular risk factors.

Sleep, health behaviors, and behavioral interventions: Reducing the risk of cardiovascular disease in adults

Numerous health behaviors, including physical activity, diet, smoking, and sleep, play a major role in preventing the development and progression of cardiovascular disease (CVD). Among these behaviors, sleep may play a pivotal role, yet it has been studied somewhat less than other behaviors and there have been few well-designed sleep intervention studies targeting CVD. Furthermore, despite the fact that these behaviors are often interrelated, interventions tend to focus on changing one health behavior rather than concurrently intervening on multiple behaviors. Psychological constructs from depression to positive affect may also have a major effect on these health behaviors and ultimately on CVD. In this review, we summarize the existing literature on the impact of sleep and other cardiac health behaviors on CVD onset and prognosis. We also describe interventions that may promote these behaviors, from established interventions such as motivational interviewing and cognitive behavioral therapy, to more novel approaches focused on mindfulness and other positive psychological constructs. Finally, we outline population-health-level care management approaches for patients with psychiatric conditions (e.g., depression) that may impact cardiac health, and discuss their potential utility in improving mental health, promoting health behaviors, and reducing CVD-related risk. Much work is still needed to better understand how sleep and other health behaviors may uniquely contribute to CVD risk, and additional high-quality studies of interventions designed to modify cardiac health behaviors are required to improve cardiovascular health in individuals and the population at large.

Autonomic and Renal Alterations in the Offspring of Sleep-Restricted Mothers During Late Pregnancy

OBJECTIVES

Considering that changes in the maternal environment may result in changes in progeny, the aim of this study was to investigate the influence of sleep restriction during the last week of pregnancy on renal function and autonomic responses in male descendants at an adult age.

METHODS

After confirmation of pregnancy, female Wistar rats were randomly assigned to either a control or a sleep restriction group. The sleep-restricted rats were subjected to sleep restriction using the multiple platforms method for over 20 hours per day between the 14th and 20th day of pregnancy. After delivery, the litters were limited to 6 offspring that were designated as offspring from control and offspring from sleep-restricted mothers. Indirect measurements of systolic blood pressure (BPi), renal plasma flow, glomerular filtration rate, glomerular area and number of glomeruli per field were evaluated at three months of age. Direct measurements of cardiovascular function (heart rate and mean arterial pressure), cardiac sympathetic tone, cardiac parasympathetic tone, and baroreflex sensitivity were evaluated at four months of age.

RESULTS

The sleep-restricted offspring presented increases in BPi, glomerular filtration rate and glomerular area compared with the control offspring. The sleep-restricted offspring also showed higher basal heart rate, increased mean arterial pressure, increased sympathetic cardiac tone, decreased parasympathetic cardiac tone and reduced baroreflex sensitivity.

CONCLUSIONS

Our data suggest that reductions in sleep during the last week of pregnancy lead to alterations in cardiovascular autonomic regulation and renal morpho-functional changes in offspring, triggering increases in blood pressure.

Association between genetic variants of the clock gene and obesity and sleep duration

Obesity is a multifactorial disease caused by the interaction of genetic and environmental factors related to lifestyle aspects. It has been shown that reduced sleep is associated with increased body mass index (BMI). Circadian Locomotor Output Cycles Kaput (CLOCK) gene variants have also been associated with obesity. The objective of this mini-review was to discuss the available literature related to CLOCK gene variants associated with adiposity and sleep duration in humans. In total, 16 articles complied with the terms of the search that reported CLOCK variants associated with sleep duration, energy intake, and BMI. Overall, six CLOCK single nucleotide polymorphisms (SNPs) have been associated with sleep duration, and three variants have been associated with energy intake variables. Overall, the most studied area has been the association of CLOCK gene with obesity; close to eight common variants have been associated with obesity. The most studied CLOCK SNP in different populations is rs1801260, and most of these populations correspond to European populations. Collectively, identifying at risk CLOCK genotypes is a new area of research that may help identify individuals who are more susceptible to overeating and gaining weight when exposed to short sleep durations.

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.

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.

Racial differences in self-reports of short sleep duration in an urban-dwelling environment

OBJECTIVES

To explore whether there are differences in sleep duration between blacks and whites residing in similar urban neighborhoods and examine whether the relationship between sleep durations and sociodemographic and/or health indices are consistent for blacks and whites.

METHODS

A total of 1,207 participants from the Healthy Aging in Neighborhoods of Disparities across the Life Span study (age: mean = 47, standard deviation = 8.74). Sleep duration was assessed by a self-report of hours of nightly sleep in the past month. Sociodemographic measures included age, sex, education, poverty status, and perceived neighborhood disorder. Health status was assessed using measures of vigilance, depression, perceived stress, coronary artery disease, diabetes, blood pressure, and inflammation.

RESULTS

There were no significant racial group differences in sleep duration. Whites, however, were more likely than blacks to report sleep durations of <6/6-7 hr compared with >7 hr with increasing stress and education levels. Blacks were more likely than whites to report short sleep durations (i.e., 6-7 hr vs. >7 hr of sleep) with increasing inflammation levels.

DISCUSSION

Although racial disparities in sleep duration are minimized when the environment is equivalent between blacks and whites, the underlying demographic and health explanations for short sleep durations may vary between whites and blacks.

Association of self-reported sleep and hypertension in non-insomniac elderly subjects

OBJECTIVES

Sleep duration and sleep quality play important roles in the development of hypertension (HT) in middle-aged subjects, with controversial data in elderly. In this study, we investigated the link between HT and self-reported sleep in non-insomniac elderly subjects.

METHODS

We examined 500 participants without insomnia complaints aged 72 ± 1 years. An extensive instrumental evaluation was carried out, including 24-h blood pressure (BP) monitoring and an assessment of nocturnal BP dipping. Sleep duration and quality were evaluated by the Pittsburgh Sleep Quality Index (PSQI). The subjects were stratified into three groups according to sleep duration: short (< 6 h), normal (> 6h to < 8 h), and long (> 8 h) sleepers. A PSQI < 5 defined good sleepers (GS, n = 252), and a PSQI > 5 (n = 248) defined poor sleepers (PS).

RESULTS

PS represented 50% of the subjects, more frequently females. Compared to GS, PS did not differ in terms of HT, BP, baroreflex sensitivity (BRS), and BP dipping. Short, normal, and long sleepers accounted for 28%, 42%, and 30% of subjects, with HT, BP values, BRS, and gender not differing between groups. No relationship was found between nocturnal BP values and self-reported sleep measures. Logistic regression analysis indicated that neither sleep duration nor sleep quality predicts the prevalence of HT, the body mass index being the only factor affecting this association.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers NCT00759304 and NCT00766584.

CONCLUSIONS

In a sample of non-insomniac elderly subjects, neither sleep duration nor sleep quality affected the prevalence of HT. These data argue against a relationship between self-reported sleep duration and quality and HT in elderly without insomnia.

Epidemiological evidence for the link between sleep duration and high blood pressure: a systematic review and meta-analysis

OBJECTIVES

We aim to assess if the relationship between short or long sleep duration and hypertension is present among adults from epidemiological evidence and to investigate the relationship quantitatively.

METHODS

We performed a comprehensive search of cross-sectional and longitudinal studies using PubMed and the Cochrane Library through February 2012. Our search was supplemented by reviewing reference lists of original and relevant reviews. After the related data were extracted by two investigators independently, pooled odds ratios (ORs) or relative risks (RRs) were estimated using a random-effects model or a fixed-effects model. Publication bias was evaluated, while sensitivity and meta-regression analyses were performed.

RESULTS

Twenty-four adult studies met our inclusion criteria, with ages ranging from 18 to 106 years. Twenty-one studies involving 225,858 subjects were included in the meta-analysis. The pooled results from the cross-sectional studies showed that short sleep duration was associated with a greater risk for hypertension (OR, 1.21; 95% confidence interval [CI], 1.09-1.34; P<0.001), and long sleep duration also increased the risk for hypertension (OR, 1.11; 95% CI, 1.04-1.18; P=0.003). There was no evidence of publication bias. Pooled analysis from the longitudinal studies indicated a significant association between short sleep duration and hypertension (RR, 1.23; 95% CI, 1.06-1.42; P=0.005), but an insignificant relationship between long sleep duration and hypertension (RR, 1.02; 95% CI, 0.91-1.14; P=0.732). The effects of sleep duration differed by gender, location of the population, and definitions of short or long sleep duration. Meta regression analysis including seven variables did not find the sources of heterogeneity.

CONCLUSIONS

Among adults, a U-shaped relationship between habitual sleep duration and hypertension was found at the cross-sectional level. Short sleep duration was associated with a higher risk for hypertension even longitudinally. We must pay more attention to this lifestyle factor.

Obesity prevention and intervention in dental practice

Dentists have an important role in preventing and detecting oral and systemic diseases because of their diagnostic and screening abilities and the frequency of patient visits. These skills and practice paradigms should be considered in solving the obesity epidemic. The well-described connection between periodontal disease and diabetes is a reason for dentists to intervene in the rise of obesity. Dentists are in a unique position to identify and aid in treatment of obstructive sleep apnea, a condition associated with obesity and diabetes. Dentists can play a role in raising awareness of overweight status and obesity risk behaviors in children.

Short sleep duration is associated with hypertension risk among adults: a systematic review and meta-analysis

A number of studies have reported that sleep duration might have an important role in the development of hypertension. However, the results have been inconsistent. In this study, a meta-analysis was performed to clarify the association between sleep duration and hypertension risk. PubMed, Embase and ISI web of science databases updated on 28 October 2011 were searched for eligible publications. Pooled odds ratio (OR) or relative risk (RR) with 95% confidence intervals (CI) was calculated using a random- or fixed-effect model. Six prospective (N=9959) and seventeen cross-sectional (N=105432) studies were identified for the data analysis on sleep duration. The results indicated that short sleep duration was associated with an increased risk of prevalent hypertension (OR=1.20, 95% CI: 1.09-1.32, P<0.001), especially among subjects younger than 65 years and females. In addition, short sleep duration was also associated with an increased risk of incident hypertension among subjects younger than 65 years (RR=1.33, 95% CI: 1.11-1.61, P=0.002). Overall, there was a significant association between long sleep duration and the risk of prevalent hypertension (OR=1.11, 95% CI: 1.05-1.17, P<0.001). Further subgroup analysis also suggested a significant association between long sleep duration and the risk of prevalent hypertension among subjects younger than 65 years (OR=1.12, 95% CI: 1.06-1.19, P<0.001). The present meta-analysis indicated that short sleep duration was associated with an increased risk of hypertension in the overall polulation and incident hypertension among subjects younger than 65 years. In addition, long sleep duration might be associated with a risk of prevalent hypertension, especially among subjects younger than 65 years.