Relationship between Chronic Short Sleep Duration and Childhood Body Mass Index: A School-Based Cross-Sectional Study

Objective

To assess relationship between obesity and chronic shorter sleep duration in children and to determine if lack of sleep represents an independent determinant of childhood Body Mass Index.

Methods

This cross-sectional study was conducted in all children enrolled in the fifth class (approximately 10 years of age) of all public primary schools in Catanzaro (Southern Italy). The overall response rate was 62% resulting in 542 participating children. Parents completed a questionnaire with information on their demographics and socio-economic characteristics, their health status, characteristics of their child birth and health status. The sleeping habits were investigated in the 3 months preceding the consultation and parents were asked to indicate hours of bedtime and wake-up of their children. Multivariate linear regression analysis was performed to examine the association between child BMI and chronic lack of sleep.

Results

36.7% of the children surveyed were overweight or obese. A quarter of children did not routinely play sports and many of them spent more than an hour a day watching TV (60.7%) and using videogames or computer (51.1%). Widespread dietary habits were inadequate, especially concerning vegetables and fruit intake with more than 95% of children who consumed insufficient amounts. The average duration of sleep was equal to 9.4 (SD = ±0.6) hours, and the short-sleepers accounted for 38.9% of the total sample. The results of multivariate analysis showed a significant 0.77 Kg/m² increase of BMI for children classified as short compared to normal sleepers (95%CI = 0.16–1.38, p = 0.01).

Conclusions

Chronic lack of sleep appears to be associated to higher BMI even in middle childhood and strongly suggests that public health strategies, focused on promoting healthy lifestyles should include an innovative approach to ensure an adequate duration of sleep at night especially in children, alongside more traditional approaches.     

Sleep Duration and Obesity in Middle‐aged Australian Adults

The present study examined the association between sleep duration and obesity in 40,834 middle‐aged Australian adults. Multinomial logistic regression was used to test the relationship between sleep duration and obesity while controlling for important demographic and health covariates; separate models were tested for males and females. Short sleep (i.e., <7 h a night) was found to be independently associated with obesity in males and females. To our knowledge, this is the first study to report an association between short sleep and obesity in Australian adults. Although more research is required, interventions targeting short sleep could aid obesity treatment and prevention.     

Sleep Duration and Quality Associated With Obesity Among Arab Children

The link between sleep duration and obesity has been well established in adults, but several epidemiological studies revealed inconsistent findings in adolescents and younger children. This study aimed to investigate the relationship between sleep length and obesity in Saudi students. A total of 5,877 Saudi students, boys (55.2%) and girls (44.8%), aged between 10 and 19 years were randomly selected from elementary, intermediate, and secondary schools in different regions of Riyadh. A questionnaire on sleep behaviors was given. Anthropometry included BMI and waist and hip circumferences. Sleeping ≤7 h significantly increased the risk of obesity in both boys and girls (all age categories) (odds ratio = 1.25–1.38, 95% confidence intervals = 1.02–1.89). Overall prevalence of overweight and obese were higher among those sleeping intermittently (18.68%) than those sleeping continuously (14.5%) (P = 0.024). Short sleep duration and poor sleep quality are significantly associated with obesity among Arab youth. Further studies need to employ more objective measures of sleep, such as actigraphy, and examine the mechanism of these associations.     

Associations of a Short Sleep Duration,Insufficient Sleep,and Insomnia with Self-Rated Health among Nurses

Epidemiological evidence suggests that sleep duration and poor sleep are associated with mortality, as well as with a wide range of negative health outcomes. However, few studies have examined the association between sleep and self-rated health, particularly through the combination of sleep complaints. The objective of this study was to examine whether self-rated health is associated with sleep complaints, considering the combination of sleep duration, insomnia, and sleep sufficiency. This cross-sectional study was performed in the 18 largest public hospitals in the city of Rio de Janeiro, Brazil. A total of 2518 female nurses answered a self-filled multidimensional questionnaire. The adjusted odds ratios and 95% confidence intervals (CIs) estimated the chance of poor self-rated health in the presence of different combinations of sleep duration and quality. Compared with women who reported adequate sleep duration with no sleep quality complaints (reference group), the odds ratios (95% CI) for poor self-rated health were 1.79 (1.27–2.24) for those who reported only insufficient sleep, 1.85 (0.94–3.66) for only a short sleep duration, and 3.12 (1.94–5.01) for only insomnia. Compared with those who expressed all three complaints (short sleep duration, insomnia, and insufficient sleep), the odds ratio for poor self-rated health was 4.49 (3.25–6.22). Differences in the magnitude of the associations were observed, depending on the combination of sleep complaints. Because self-rated health is a consistent predictor of morbidity, these results reinforce the increasing awareness of the role of sleep in health and disease. Our findings contribute to the recognition of sleep as a public health matter that deserves to be better understood and addressed by policymakers.     

Obesity and the Role of Short Duration Submaximal Work on Cardiovascular and Cerebral Hemodynamics

The objective of this study was to compare gas exchange, cardiac and cerebral hemodynamic responses between 10 non-obese and 10 obese men during submaximal work. With the increasing prevalence of obesity, there is a need to understand the impact of obesity on work-induced responses. Participants completed a step-wise incremental cycling until they reached 60% of their age-predicted maximum heart rate. Gas exchange, cardiac and pre-frontal cortex hemodynamic responses were simultaneously measured during rest, work, and recovery. The non-obese group reached ~43% of their predicted maximal aerobic capacity as compared to ~34% in the obese group, with the non-obese working at a relatively higher workload and for more duration than the obese. The obese had elevated baseline heart rate and reduced whole-body oxygen uptake per body weight at baseline and task termination. Other cardiac and cerebral responses, although increased from baseline, were similar between groups during submaximal effort. In the obese, during recovery oxygen uptake and heart-rate recovery were slowest; cardiac output and rate pressure product were greatest, and left ventricle ejection time was shortest. However, both groups exhibited similar cerebral hemodynamics during recovery. These finding imply that, irrespective of their low aerobic fitness, obesity does not impair myocardial performance and cerebrovascular function during graded submaximal work, however, recovery from a short duration of work was influenced by their fitness level. Since a majority of activities of daily living are performed at individual’s submaximal level, understanding influence of obesity on submaximal work is critical.     

Association of Maternal Short Sleep Duration With Adiposity and Cardiometabolic Status at 3 Years Postpartum

The purpose of this study was to examine the association of short sleep duration among women in the first year postpartum with adiposity and cardiometabolic status at 3 years postpartum. We studied 586 women in Project Viva, a prospective cohort. At 6 months and 1 year postpartum, women reported the number of hours they slept in a 24‐h period, from which we calculated a weighted average of daily sleep. We used multivariable regression analyses to predict the independent effects of short sleep duration (≤5 h/day vs. >5 h/day) on adiposity, glucose metabolism, lipid metabolism, and adipokines at 3 years postpartum. Women's mean (s.d.) hours of daily sleep in the first year postpartum was 6.7 (0.97) h. After adjusting for age, race/ethnicity, education, parity, prepregnancy BMI, and excessive gestational weight gain, we found that postpartum sleep ≤5 h/day was associated with higher postpartum weight retention (β 1.50 kg; 95% confidence interval (CI): 0.02, 2.86), higher subscapular + triceps skinfold thickness (β 3.94 mm; 95% CI: 1.27, 6.60) and higher waist circumference (β 3.10 cm; 95% CI: 1.25, 4.94) at 3 years postpartum. We did not observe associations of short sleep duration with measures of cardiometabolic status at 3 years postpartum. In conclusion, short sleep duration in the first year postpartum is associated with higher adiposity at 3 years postpartum.     

The Recognition of and Care Seeking Behaviour for Childhood Illness in Developing Countries: A Systematic Review

Background

Pneumonia, diarrhoea, and malaria are among the leading causes of death in children. These deaths are largely preventable if appropriate care is sought early. This review aimed to determine the percentage of caregivers in low- and middle-income countries (LMICs) with a child less than 5 years who were able to recognise illness in their child and subsequently sought care from different types of healthcare providers.

Methods and Findings

We conducted a systematic literature review of studies that reported recognition of, and/or care seeking for episodes of diarrhoea, pneumonia or malaria in LMICs. The review is registered with PROSPERO (registration number: CRD42011001654). Ninety-one studies met the inclusion criteria. Eighteen studies reported data on caregiver recognition of disease and seventy-seven studies on care seeking. The median sensitivity of recognition of diarrhoea, malaria and pneumonia was low (36.0%, 37.4%, and 45.8%, respectively). A median of 73.0% of caregivers sought care outside the home. Care seeking from community health workers (median: 5.4% for diarrhoea, 4.2% for pneumonia, and 1.3% for malaria) and the use of oral rehydration therapy (median: 34%) was low.

Conclusions

Given the importance of this topic to child survival programmes there are few published studies. Recognition of diarrhoea, malaria and pneumonia by caregivers is generally poor and represents a key factor to address in attempts to improve health care utilisation. In addition, considering that oral rehydration therapy has been widely recommended for over forty years, its use remains disappointingly low. Similarly, the reported levels of care seeking from community health workers in the included studies are low even though global action plans to address these illnesses promote community case management. Giving greater priority to research on care seeking could provide crucial evidence to inform child mortality programmes.     

Common Variants of FTO Are Associated with Childhood Obesity in a Cross-Sectional Study of 3,126 Urban Indian Children

Background

FTO variants are robustly associated with obesity and related traits in many population and shown to have variable impact during life course. Although studies have shown association of FTO variants with adiposity in adult Indian, its association in Indian children is yet to be confirmed.

Methods

Here we examined association of FTO variants (rs9939609 and rs8050136) with obesity and related anthropometric and biochemical traits in 3,126 Indian children (aged 11–17 years) including 2,230 normal-weight and 896 over-weight/obese children. We also compared effects observed in the present study with that observed in previous studies on South Asian adults and children of other ethnic groups.

Results

The variant rs9939609 showed significant association with risk of obesity [OR = 1.21, P = 2.5×10⁻³] and its measures BMI, weight, waist circumference and hip circumference [β range = 0.11 to 0.14 Z-score units; P range = 1.3×10⁻⁴ to 1.6×10⁻⁷] in children. The observed effect sizes in Indian children were similar to those reported for European children. Variant rs9939609 explained 0.88% of BMI variance in Indian children. The effect sizes of rs9939609 on BMI and WC were ∼2 fold higher in children than adults. Interestingly rs9939609 was also associated with serum levels of thyroid stimulating hormone (TSH) [β = 0.10 Z-score, P = 5.8×10⁻³]. The other variant rs8050136 was in strong linkage disequilibrium with rs9939609 (r² = 0.97) and provided similar association results.

Conclusion

The study provides first report of association of FTO variants with obesity and related anthropometric traits in Indian children with higher impact in children compared to adults. We also demonstrated association of FTO variant with serum levels of TSH, indicating putative influence of FTO in hypothalamic-pituitary-thyroid axis.     

Central Obesity and Albuminuria: Both Cross-Sectional and Longitudinal Studies in Chinese

Background

Albuminuria is recognized as a marker of vascular dysfunction. Central obesity increases the risk of cardiovascular disease. Little is known about the association between albuminuria and central obesity in Chinese. We aimed to assess the association between central obesity and prevalence and incidence of albuminuria in a middle-aged population-based cohort study.

Methods

This is a cross-sectional and longitudinal cohort study. A total of 2350 subjects aged ≥40 years were recruited in 2004 in Taiwan for cross-sectional analysis. Longitudinal analysis included 1432 baseline normoalbuminuria subjects with a mean 2.8 years follow-up, 67 of whom exhibited incident albuminuria. Albuminuria was defined as urinary albumin-to-creatinine ratio ≥30 mg/g creatinine. Multiple logistic regression analyses were used to evaluate the relationship between central obesity and prevalence and incidence of albuminuria after adjustment for age, gender, body mass index, blood pressure, renal function, glucose, high sensitivity c-reactive protein, smoking, betel nut chewing, alcohol drinking, and physical activity.

Results

At baseline, albuminuria is significantly associated with central obesity. The adjusted odds ratio of having albuminuria among subjects with central obesity was 1.73(95% confidence interval (CI): 1.04–2.85), compared to the subjects without central obesity. In multivariable models, participants with central obesity at baseline had a 112% increase in risk of incident albuminuria (adjusted incidence rate ratio (95% CI): 2.12(1.01–4.44)) compared with participants with non-central obesity.

Conclusions

Abdominal adiposity was independently associated with increased prevalence and incidence of albuminuria in Chinese. The mechanisms linking adiposity and albuminuria need to be addressed.     

儿童肥胖与代谢综合征相关性的研究进展

近年来,儿童肥胖的检出率呈逐年增长趋势,代谢综合征是以糖代谢异常、血脂异常、高血压、中心性肥胖等集聚于一体的症候群。儿童肥胖是儿童代谢综合征发生的中心因素,严重影响儿童的身心健康,应及早诊断及治疗,而控制儿童肥胖的发生和发展是预防代谢综合征,降低成人心血管疾病、糖尿病等发病率的重要因素。治疗上重在预防,建议合理饮食、加强锻炼,阻止儿童肥胖及代谢综合征的流行与发展。本文针对儿童肥胖与代谢综合征相关性的研究进展进行综述,并提出进一步研究的设想。     

A Review of Dietary and Environmental Correlates of Obesity with Emphasis on Developing Countries

The relationships between dietary and environmental factors and obesity are reviewed. Findings from selected population studies of diet and body weight are presented. In general, the results from population studies of diet and obesity have been inconsistent and marked with methodological weaknesses, especially the use of cross-sectional study design. Apart from the diet, several social and economic factors appear to be important correlates of obesity in the population. However, most studies have focused on the socioeconomic status as abroad, composite measure. The relationships between income, education, occupation, place of residence, and obesity are reviewed here, with emphasis on the developing countries. In many developing countries, the changing dietary pattern, along with rising life expectancy and changing socioeconomic environment, has contributed to the increasing problems of obesity and other diet-related chronic diseases that will have an enormous impact on the health and health care resource of these countries in the near future.     

Medical Student Knowledge of Neglected Tropical Diseases in Peru: A Cross-Sectional Study

In developing countries, education to health-care professionals is a cornerstone in the battle against neglected tropical diseases (NTD). Studies evaluating the level of knowledge of medical students in clinical and socio-demographic aspects of NTD are lacking. Therefore, a cross-sectional study was conducted among students from a 7 year-curriculum medical school in Peru to assess their knowledge of NTD by using a pilot survey comprised by two blocks of 10 short questions. Block I consisted of socio-demographic and epidemiological questions whereas block II included clinical vignettes. Each correct answer had the value of 1 point. Out of 597 responders (response rate: 68.4%), 583 were considered to have valid surveys (male:female ratio: 1:1.01; mean age 21 years, SD ± 2.42). Total knowledge showed a raising trend through the 7-year curriculum. Clinical knowledge seemed to improve towards the end of medical school whereas socio-demographic and epidemiological concepts only showed progress the first 4 years of medical school, remaining static for the rest of the curricular years (p = 0.66). Higher mean scores in socio-demographic and epidemiological knowledge compared to clinical knowledge were seen in the first two years (p<0.001) whereas the last three years showed higher scores in clinical knowledge (p<0.001). In conclusion, students from this private medical school gained substantial knowledge in NTD throughout the career which seems to be related to improvement in clinical knowledge rather than to socio-demographic and epidemiological concepts. This study assures the feasibility of measuring the level of knowledge of NTD in medical students and stresses the importance of evaluating education on NTD as it may need more emphasis in epidemiological concepts, especially at developing countries such as Peru where many people are affected by these preventable and treatable diseases.     

Short Sleep Duration Is Associated with Shorter Telomere Length in Healthy Men: Findings from the Whitehall II Cohort Study

Background

Shorter telomere length and poor sleep are more prevalent at older ages, but their relationship is uncertain. This study explored associations between sleep duration and telomere length in a sample of healthy middle and early old age people.

Methods

Participants were 434 men and women aged 63.3 years on average drawn from the Whitehall II cohort study. Sleep duration was measured by self-report.

Results

There was a linear association between sleep duration and leukocyte telomere length in men but not in women (P = 0.035). Men reporting shorter sleep duration had shorter telomeres, independently of age, body mass index, smoking, educational attainment, current employment, cynical hostility scores and depressive symptoms. Telomeres were on average 6% shorter in men sleeping 5 hours or fewer compared with those sleeping more than 7 hours per night.

Conclusion

This study adds to the growing literature relating sleep duration with biomarkers of aging, and suggests that shortening of telomeres might reflect mechanisms through which short sleep contributes to pathological conditions in older men.     

Short Sleep Duration Is Associated with Risk of Future Diabetes but Not Cardiovascular Disease: a Prospective Study and Meta-Analysis

Epidemiologic studies have observed association between short sleep duration and both cardiovascular disease (CVD) and type 2 diabetes, although these results may reflect confounding by pre-existing illness. This study aimed to determine whether short sleep duration predicts future CVD or type 2 diabetes after accounting for baseline health. Baseline data for 241,949 adults were collected through the 45 and Up Study, an Australian prospective cohort study, with health outcomes identified via electronic database linkage. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals. Compared to 7h sleep, <6h sleep was associated with incident CVD in participants reporting ill-health at baseline (HR=1·38 [95% CI: 1·12-1·70]), but not after excluding those with baseline illness and adjusting for baseline health status (1·03 [0·88-1·21]). In contrast, the risk of incident type 2 diabetes was significantly increased in those with <6h versus 7h sleep, even after excluding those with baseline illness and adjusting for baseline health (HR=1·29 [1·08-1·53], P=0.004). This suggests the association is valid and does not simply reflect confounding or reverse causation. Meta-analysis of ten prospective studies including 447,124 participants also confirmed an association between short sleep and incident diabetes (1·33 [1·20-1·48]). Obtaining less than 6 hours of sleep each night (compared to 7 hours) may increase type 2 diabetes risk by approximately 30%.     

Differences in Overweight and Obesity among Children from Migrant and Native Origin: The Role of Physical Activity,Dietary Intake,and Sleep Duration

A cross-sectional survey was performed to examine to what degree differences in overweight and obesity between native Dutch and migrant primary school children could be explained by differences in physical activity, dietary intake, and sleep duration among these children. Subjects (n=1943) were primary school children around the age of 8–9 years old and their primary caregivers: native Dutch children (n=1546), Turkish children (n=93), Moroccan children (n=66), other non-western children (n=105), and other western children (n=133). Multivariate regressions and logistic regressions were used to examine the relationship between migrant status, child’s behavior, and BMI or prevalence of overweight, including obesity (logistic). Main explanatory variables were physical activity, dietary intake, and sleep duration. We controlled for age, sex, parental educational level, and parental BMI. Although sleep duration, dietary intake of fruit, and dietary intake of energy-dense snacks were associated with BMI, ethnic differences in sleep duration and dietary intake did not have a large impact on ethnic differences in overweight and obesity among children from migrant and native origin. It is suggested that future preventive strategies to reduce overweight and obesity, in general, consider the role of sleep duration. Also, cross-cultural variation in preparation of food among specific migrant groups, focusing on fat, sugar, and salt, deserves more attention. In order to examine which other variables may clarify ethnic differences in overweight and obesity, future research is needed.