Nutritional status, growth and sleep habits among Senegalese adolescent girls

The Relationship between Sleep, Obesity, and Metabolic Health in Adolescents - a Review

In this literature review, we discuss the importance of adequate sleep and the various effects of suboptimal sleep on weight maintenance and metabolic health specifically for adolescents. Two major contributors to adolescents experiencing decreased sleep duration and quality, and thus increasing the risk for developing metabolic syndrome in adolescence as well as later in adulthood, are increased electronic screen time particularly at night and early school start times. The less time adolescents spend sleeping, the less quality sleep they obtain, and the greater the disruption of endocrine hormone function. As another consequence, adolescents are more prone to making poor food choices, from choosing relatively nutrient-poor foods to consuming excess calories without necessarily increasing their energy expenditure. These choices put adolescents at greater risk for becoming obese throughout their lifespan.

The double burden of malnutrition in a rural health and demographic surveillance system site in South Africa: a study of primary schoolchildren and their mothers

BACKGROUND

In South Africa, the occurrence of the double burden of malnutrition is on the rise at a household level predisposing children and their mothers to negative health outcomes. However, few studies have been conducted at a household level. Therefore, we studied a double burden of malnutrition using child-mother pairs in a rural setting.

METHODS

A cross-sectional quantitative survey was conducted among 508 child-mother pairs selected from primary schools using a multistage sampling in a rural Dikgale Health and Demographic Site in Limpopo Province, South Africa. Anthropometric measurements of children and mothers, and socio-demographic data were collected. WHO AnthroPlus was used to generate body-mass-index z-scores of children and the BMI was used to indicate overweight and obesity among the mothers. Mann Whitney test was used to compare the means of variables between sexes and age groups, while the prevalence of thinness and overweight/obesity were compared using a chi-square. Multivariate logistic regression with a stepwise backward elimination procedure, controlling for confounding, was used to determine the association between the thinness and overweight/obesity and the covariates.

RESULTS

Twenty five percent (25%) of the children were thin, 4% were overweight and 1% obese, while mothers were overweight (27.4%) and 42.3% obesity (42.3%) were observed among the mothers. The odds of being thin were higher in boys than in girls (AOR = 1.53, 95%CI: 1.01-2.35). Overweight/obese mothers were more likely to have thin children (AOR = 1.48, 95% CI: 1.01-2.18) and less likely to have overweight/obese children (AOR = 0.18, 95%CI: 0.07-0.46).

CONCLUSION

A double burden of malnutrition was observed on a household level with thinness among children and overweight/obesity among mothers. A need to address the dual problems of undernutrition and rapidly rising trends of overweight/obesity cannot be over-emphasized.

Community, household, and individual correlates of sleep behaviors in Guyanese female youth

OBJECTIVES

Chronic sleep loss among youth is a worldwide health problem. Since research on its predictors is often limited to high-income countries, it is unclear if these findings are generalizable to all populations. To address this gap from an ecological perspective, we evaluated the associations between adolescents' sleep behaviors and several factors at the community, household, and individual levels in a middle-income country.

METHODS

This was a cross-sectional study of 73 girls (mean age = 14.5 y; range = 11-18 y) in rural and urban communities in Guyana. Sleep behaviors (nap-duration, bedtime, rise-time, night-bed-duration, and sleep-duration) were assessed with interviews and monitored up to 7 consecutive days using waist-worn accelerometers.

RESULTS

Similar to other settings, Guyanese urban youth reported significantly later bedtimes than rural youth, and increasing age was associated with later bedtime and shorter night-bed-duration. In contrast to the association observed in high-income countries, increasing household poverty scores in Guyana were associated with longer night-bed-duration.

CONCLUSIONS

Although the relationships between locale, age, and sleep in Guyana paralleled patterns seen in high-income countries, the positive relationship between poverty and sleep diverges from previous reports. These findings suggest that predictors of chronic sleep loss seen in high-income countries are likely to differ from those in middle- and low-income countries. More sleep studies in underrepresented populations are needed to gain a comprehensive understanding of adolescent sleep behavior and its correlates.

Randomised study found that improved nutritional intake was associated with better sleep patterns in prepubertal children who were both short and lean

AIMS

Nutrition and sleep are prerequisites for linear growth and we addressed the under-researched role of sleep in this equation.

METHODS

This was a prospective randomised, double-blinded, placebo-controlled study of nutritional supplements in 164 healthy lean, short, prepubertal children with 83 in the supplement group and 81 in the placebo group. From November 2010 to November 2013, we focussed on children aged three to nine years referred for specialist growth assessments to the Schneider Children's Medical Center, Israel. Progress was assessed using anthropometric measurements, sleep questionnaires and three-day food diaries at baseline and after the six-month intervention.

RESULTS

Children in the supplement group who took at least 50% of the recommended dose had shorter sleep latency than those who did not (p = 0.046). Children who fell asleep in less than 15 minutes had significantly improved standard deviation scores for weight (0.25 ± 0.34 versus 0.07 ± 0.36, p = 0.044) and height (0.09 ± 0.13 versus 0.03 ± 0.13, p = 0.057) than those who took longer to fall asleep. Positive correlations were found between mean sleep duration and caloric and macronutrient intake per kilogram.

CONCLUSION

Adequate nutritional intake was associated with better sleep patterns and may enhance linear growth.

Modifiable predictors of insufficient sleep durations: A longitudinal analysis of youth in the COMPASS study

The purpose of the current study was to simultaneously examine commonly proposed risk and protective factors for sleep deprivation over time among a large cohort of Ontario and Alberta secondary school students. Using 4-year linked longitudinal data from youth in years 1 through 4 (Y₁[2012/2013], Y₂[2013/2014], Y₃[2014/2015], Y₄[2015/2016]) of the COMPASS study (n=26,205), the likelihood of students meeting contemporary sleep recommendations was tested based on their self-reported substance use, bullying victimization, physical activity, and homework and screen time. Models controlled for the effect of student-reported gender, race/ethnicity, grade, school clustering, and all other predictor variables. Relative to baseline, students became less likely to meet the sleep recommendations if at follow-up they had initiated binge drinking, experienced cyber bullying victimization, or were spending more time doing homework, with other factors held constant. The likelihood of reporting sufficient sleep increased if students had begun engaging in resistance training at least three times a week. No longitudinal effect was observed when students increased their caffeine consumption (energy drinks, coffee/tea), initiated cannabis or tobacco use, experienced other forms of bullying victimization (physical, verbal, or belongings), engaged in more moderate-vigorous physical activity, or increased their screen use of any type. Few of the commonly purported modifiable risk and protective factors for youth sleep deprivation held in multinomial longitudinal analyses. Causal conclusions appear premature, with further research required to confirm the targets likely to be most effective in assisting more youth in meeting the sleep recommendations.

Sleep is in for Summer: Patterns of Sleep and Physical Activity in Urban Minority Girls

OBJECTIVE

Urban minority girls are at risk for summertime weight gain, and may also experience insufficient summertime sleep. Few studies have objectively measured sleep in this population or examined correlates, including physical activity (PA). This study is the first to objectively describe summertime sleep among urban minority girls.

METHODS

Data were collected at a community-based summer program that promoted PA (n = 60 girls, ages 10-14 years), at two time points: before beginning programming (T1; unstructured context) and during the final week of programming (T2; structured context).

RESULTS

At both time points, participants experienced shorter nighttime sleep than the recommended amount for girls their age. African American girls recorded significantly less sleep than Latina girls in the unstructured context. Findings also suggest that sleep schedules have an influential role in youths' abilities to obtain adequate sleep.

CONCLUSION

Overall, summertime sleep is an understudied health behavior that may be important to consider among minority youth.

Night-time sleep duration and the incidence of obesity and type 2 diabetes. Findings from the prospective Pizarra study

BACKGROUND

Several recent studies have related short sleep duration with different health problems, though the results related with the risk of obesity and type 2 diabetes (T2D) are far from conclusive. The aim of this study was to investigate the association between night-time sleep duration and the incidence of obesity and T2D in a prospective study with a follow-up of 11 years.

MATERIAL AND METHODS

The study comprised 1145 people evaluated in 1997-1998 and re-evaluated after 6 years and 11 years. At the three study points, subjects without known diabetes mellitus (KDM) were given an oral glucose tolerance test (OGTT). Anthropometric and biochemical variables were measured. The subjects were asked about their number of hours of night-time sleep.

RESULTS

After adjustment, the OR of becoming obese was significantly higher in subjects who slept ≤ 7 hours per night, at both the 6-year follow-up (OR = 1.99; 95% CI = 1.12-3.55) and the 11-year follow-up (OR = 2.73; 95% CI = 1.47-5.04). The incidence of T2D at the 6-year follow-up in subjects without T2D at baseline was higher in those who slept ≤ 7 hours per night (OR = 1.96; 95% CI = 1.10-3.50). However, this association was not independent of obesity, weight gain or abnormal glucose regulation at baseline. At the 11-year follow-up however there was no association between night-time sleep duration and the incidence of T2D.

CONCLUSIONS

The incidence of obesity over the 11-year follow-up increased in subjects with fewer hours of night-time sleep. The incidence of T2D according to the hours of night-time sleep depended on obesity and the carbohydrate metabolism phenotype.

Lifestyle correlates of self-reported sleep duration among Saudi adolescents: a multicentre school-based cross-sectional study

BACKGROUND

Lifestyle factors are important determinants of adequate sleep among adolescents. However, findings on sleep duration relative to lifestyle factors are conflicting. Therefore, this study examined the association of self-reported sleep duration with physical activity, sedentary behaviours and dietary habits among Saudi adolescents.

METHODS

A multicentre school-based cross-sectional study was conducted in three major cities in Saudi Arabia. The sample included 2868 secondary-school students (51.9% girls) aged 15-19 years, randomly selected using a multistage stratified cluster sampling technique. In addition to anthropometric measurements, sleep duration, physical activity, sedentary behaviours and dietary habits were assessed using self-reported questionnaire.

RESULTS

Several lifestyle factors were associated with sleep duration in adolescents. While controlling for some potential confounders, the findings showed that high screen time [>5 h/day; adjusted odds ratio (aOR) = 1.505, 95% confidence interval (CI) = 1.180-1.920, P = 0.001] and low (aOR = 1.290, 95% CI = 1.064-1.566, P = 0.010) to medium (aOR = 1.316, 95% CI = 1.075-1.611, P = 0.008) physical activity levels were significantly related to daily sleep of 8 h or longer. Furthermore, having low intake of breakfast (<3 day/week compared with 5 days or more per week) decreased the odd of having adequate sleep duration by a factor of 0.795 (95% CI = 0.667-0.947, P < 0.010).

CONCLUSIONS

Short sleep duration (<8 h/day) among Saudi adolescents 15-19 year olds was significantly associated with several lifestyle factors. Intervention programs aiming for improving sleeping habits among adolescents need to consider such potential association of lifestyle variables with sleep duration.

Evidence of an overweight/obesity transition among school-aged children and youth in Sub-Saharan Africa: a systematic review

BACKGROUND

Prevalence of childhood overweight/obesity has increased considerably in recent years. The transition to higher rates of overweight/obesity has been well documented in high income countries; however, consistent or representative data from lower income countries is scarce. It is therefore pertinent to assess if rates of overweight/obesity are also increasing in lower income countries, to inform public health efforts.

OBJECTIVE

This systematic review aimed to investigate the evidence for an overweight/obesity transition occurring in school-aged children and youth in Sub Saharan Africa.

METHODS

Studies were identified by searching the MEDLINE, Embase, Africa Index Medicus, Global Health, Geobase, and EPPI-Centre electronic databases. Studies that used subjective or objective metrics to assess body composition in apparently healthy or population-based samples of children and youth aged 5 to 17 years were included.

RESULTS

A total of 283 articles met the inclusion criteria, and of these, 68 were used for quantitative synthesis. The four regions (West, Central, East, and South) of Sub Saharan Africa were well represented, though only 11 (3.9%) studies were nationally representative. Quantitative synthesis revealed a trend towards increasing proportions of overweight/obesity over time in school-aged children in this region, as well as a persistent problem of underweight. Weighted averages of overweight/obesity and obesity for the entire time period captured were 10.6% and 2.5% respectively. Body composition measures were found to be higher in girls than boys, and higher in urban living and higher socioeconomic status children compared to rural populations or those of lower socioeconomic status.

CONCLUSIONS

This review provides evidence for an overweight/obesity transition in school-aged children in Sub Saharan Africa. The findings of this review serve to describe the region with respect to the growing concern of childhood overweight/obesity, highlight research gaps, and inform interventions.

PROSPERO REGISTRATION NUMBER

CRD42013004399.

Temporal trends and correlates of physical activity, sedentary behaviour, and physical fitness among school-aged children in Sub-Saharan Africa: a systematic review

Recent physical activity (PA) and fitness transitions, identified as behavioural shifts from traditionally active lifestyles to more industralised and sedentary lifestyles, have been observed among school-aged children. There is a wealth of supporting evidence of such behavioural transitions in high income countries; however, a paucity of data on lower income countries exists. These transitions pose a particular threat to the welfare of children by accelerating the onset of chronic diseases. This systematic review investigated the evidence for a PA and fitness transition among Sub-Saharan Africa's school-aged children. Temporal trends and correlates of PA, SB, and fitness were examined. Studies were identified by searching the Medline, Embase, Africa Index Medicus, Global Health, Geobase, and EPPI-Centre electronic databases, and were included if they measured outcomes of interest in apparently healthy samples of children (5‒17 years). A total of 71 articles met the inclusion criteria (40 informed PA, 17 informed SB, and 37 informed fitness). Vast heterogeneity in study methodology complicated analysis of transitions over time and no temporal trends were immediately discernible. However, higher socioeconomic status, urban living, and female children were found to engage in lower levels of PA, higher SB, and performed worse on aerobic fitness measures compared to lower socioeconomic status, rural living, and male children. Data revealed that urbanization was associated with a trend towards decreased PA, increased SB, and decreased aerobic fitness over time. Representative, temporally sequenced data examining a PA and fitness transition are lacking in this region (PROSPERO Registration Number: CRD42013004399).

Sleep duration of underserved minority children in a cross-sectional study

Background

Short sleep duration has been shown to associate with increased risk of obesity. Childhood obesity is more prevalent among underserved minority children. The study measured the sleep duration of underserved minority children living in a large US urban environment using accelerometry and its relationship with BMI, socioeconomic status (SES), gender, ethnicity and physical activity.

Methods

Time spent on sleep and physical activity among 333 Hispanic and 150 black children (9–12 y) was measured objectively by accelerometry over 5–7 consecutive days. The children were recruited at 14 underserved community centers in Houston, Texas, between January 2009 and February 2011. Body weight and height were measured in duplicate.

Results

The majority of children (88.8%) wore the monitor for 6 consecutive days. The children slept 8.8 ± 0.6 (mean ± SD) h/d and spent 45 ± 24 min/d on moderate-vigorous physical activity (MVPA). Hispanic children slept 0.2 h/d longer (P < 0.001) than black children. Obese children slept 0.2 h/d less (P < 0.02) than normal-weight children. SES had no effect on sleep duration. There was a significant interaction between gender and age (P < 0.03); girls aged 11–12 y slept 0.3 h/d less than boys and the younger girls. Children slept 0.6 h/d longer (P < 0.001) during the weekend than weekdays. No relation was detected between sleep duration and MVPA time.

Conclusions

Minority children living in a large metropolitan area in the US are not meeting the National Sleep Foundation recommendation for sleep duration of 10–11 h/d. Longitudinal studies based on objective measures are needed to establish causality between sleep duration and obesity risk among minority children.

Global obesity: trends, risk factors and policy implications

The worldwide increase in obesity and related chronic diseases has largely been driven by global trade liberalization, economic growth and rapid urbanization. These factors continue to fuel dramatic changes in living environments, diets and lifestyles in ways that promote positive energy balance. Nutritional transitions in low-income and middle-income countries are typically characterized by increases in the consumption of animal fat and protein, refined grains, and added sugar. This change is coupled with reductions in physical activity owing to more mechanized and technologically driven lifestyles. Given the high costs of obesity and comorbidities in terms of health-care expenditure and quality of life, prevention strategies are paramount, particularly in low-income and middle-income countries that must manage coexisting infectious diseases and undernutrition in addition to the obesity epidemic. As countries become increasingly urbanized, undernutrition and obesity can exist side by side within the same country, community or household, which is a particular challenge for health systems with limited resources. Owing to the scope and complexity of the obesity epidemic, prevention strategies and policies across multiple levels are needed in order to have a measurable effect. Changes should include high-level global policies from the international community and coordinated efforts by governments, organizations, communities and individuals to positively influence behavioural change.

Sleep disturbance and cardiovascular risk in adolescents

BACKGROUND

Evidence suggests that inadequate or disturbed sleep is associated with increased cardiovascular risk in adults. There are limited data on sleep quality and associated cardiovascular risk in children.

METHODS

We obtained data on adolescents from the 2009/10 cycle of the Healthy Heart Schools' Program, a population-based cross-sectional study in the Niagara region of Ontario. Participants underwent measurements of cardiometabolic risk factors, including body mass index (BMI), lipid profile and blood pressure, and they completed questionnaires measuring sleeping habits and nutritional status. We assessed sleep disturbance using the sleep disturbance score derived from the Pittsburgh Sleep Quality Index. We explored associations between sleeping habits and cardiovascular risk factors.

RESULTS

Among 4104 adolescents (51% male), the mean hours of sleep per night (± standard deviation) were 7.9 ± 1.1 on weeknights and 9.4 ± 1.6 on weekends. In total, 19% of participants reported their sleep quality as fairly bad or very bad on weeknights and 10% reported it as fairly bad or very bad on weekends. In the multivariable regression models, a higher sleep disturbance score was associated with increased odds of being at high cardiovascular risk (highest v. lowest tertile odds ratio [OR] 1.43 [95% confidence interval (CI) 1.16-1.77], p < 0.001), increased odds of hypertension (highest v. lowest tertile OR 1.44 [95% CI 1.02-2.05], p = 0.05) and increased odds of elevated non-high density lipoprotein cholesterol (highest v. lowest tertile OR 1.28 [95% CI 1.00-1.64], p = 0.05). The mean duration of sleep was not associated with these outcomes.

INTERPRETATION

In healthy adolescents, sleep disturbance is associated with cardiovascular risk factor abnormalities. Intervention strategies to optimize sleep hygiene early in life may be important for the prevention of cardiovascular disease.

Sleep deprivation is associated with lower diet quality indices and higher rate of general and central obesity among young female students in Iran

OBJECTIVES

Short sleep duration and low diet quality are associated with weight gain. However, little is known about the relationship between sleep duration and the quality of diets. Therefore, we aimed to compare the diet quality indices and anthropometric measures between short and longer sleepers.

METHODS

This cross-sectional study consisted of 410 female youths who were chosen among students of Isfahan University of Medical Sciences based on stratified random sampling method. Dietary intake assessment was done using a semiquantitative validated food frequency questionnaire. Sleep duration was estimated using self-reported nocturnal sleep duration by each person. Anthropometric measures were done using standard protocols. Diet quality indices (including dietary energy density, dietary diversity scores, healthy eating index, nutrient adequacy ratio, and mean adequacy ratio) were calculated using the standard definition.

RESULTS

Subjects who slept less than 6 h/d were more likely to be overweight and obese (P = 0.0001) and also abdominally obese (P = 0.03). They also consumed more dietary energy (2406 ± 825 versus 2092 ± 700 kcal/d; P = 0.01, respectively) and carbohydrates (58.1 ± 16.2% versus 51.6 ± 10.3%; P = 0.03) but a lower amount of fiber (12 ± 7 versus 18 ± 7 g/d; P = 0.04), fruits (2.4 ± 0.6 versus 3.1 ± 0.7 servings/d; P = 0.04), whole grains (0.9 ± 0.1 versus 1.3 ± 0.1 servings/d; P = 0.04), and beans (0.3 ± 0.1 versus 0.8 ± 0.1 servings/d; P = 0.04). All diet quality indices were significantly lower among short sleepers (P < 0.05), apart from dietary energy density, which did not differ significantly (P = 0.8).

CONCLUSION

Our findings confirm the association of short sleep duration and obesity in young female youths. It might be derived from lower diet quality among short sleepers more than longer sleepers.

Does sleep duration predict metabolic risk in obese adolescents attending tertiary services? A cross-sectional study

STUDY OBJECTIVES

To determine, in a clinical sample of obese adolescents, whether shorter sleep duration is associated with metabolic risk and obesity severity.

DESIGN

Cross-sectional study.

SETTING

Tertiary care weight-management clinic in Cincinnati, OH, USA.

PARTICIPANTS

133 obese adolescents aged 10-16.9 years.

INTERVENTIONS

N/A.

MEASUREMENTS

Multifaceted sleep duration data were examined with fasting venipuncture and anthropometric data collected during clinical care.

PRIMARY OUTCOME

presence of metabolic syndrome.

SECONDARY OUTCOMES

waist circumference, triglycerides, HDL-cholesterol, blood pressure, glucose, insulin resistance (HOMA-IR), and body mass index (BMI).

PREDICTORS

Sleep duration by (1) parent-report, (2) self-report, and (3) multi-night actigraphy.

ANALYSIS

Relationships between sleep duration and each outcome were examined via regression models, adjusted for potential confounders.

RESULTS

Regardless of how measured, sleep duration showed no strong association with metabolic syndrome (OR 1.1 to 1.5, P = 0.2 to 0.8), BMI (β -0.03 to -0.01, P = 0.2 to 0.8), or most other outcomes. Lower triglycerides were predicted by shorter sleep duration by self-report (β 12.3, P = 0.01) and actigraphy (β 13.6, P = 0.03), and shorter parent-reported sleep duration was associated with higher HDL-cholesterol (β = -2.7, P = 0.002).

CONCLUSIONS

Contrary to expectations, sleep duration was not associated with metabolic outcomes, and showed limited associations with lipid profiles. Although inadequate sleep may affect other areas of functioning, it appears premature to expect that lengthening sleep will improve BMI or metabolic outcomes in clinical samples of obese adolescents.

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

Systematic literature search for epidemiological evidence for an association of short sleep with weight gain and eventual development of obesity provided 71 original studies and seven reviews of various subsets of these studies. We have summarized the evidence for such an association with particular emphasis on prospective studies. The studies showed that short sleep duration is consistently associated with development of obesity in children and young adults, but not consistently so in older adults. We have identified critical aspects of the evidence, and assessed the possibility for interpretation of the evidence in terms of causality. We have discussed the requirement of temporal sequence between putative exposure and outcome and the implications of the time lag between them, the problems in adequate measurements of exposure and effects, the possible bidirectional causal effects, the necessary distinction between confounders and mediators, the possible confounding by weight history, and the possibility of common or upstream underlying causes. In conclusion, causal interpretation of the association is hampered by fundamental conceptual and methodological problems. Experimental studies may elucidate mechanisms, but adequate coverage of the entire pathway from sleep curtailment through obesity development is not feasible. Randomized trials are needed to assess the value of targeted interventions.

Acute partial sleep deprivation increases food intake in healthy men

BACKGROUND

Acute partial sleep deprivation increases plasma concentrations of ghrelin and decreases those of leptin.

OBJECTIVE

The objective was to observe modifications in energy intake and physical activity after acute partial sleep deprivation in healthy men.

DESIGN

Twelve men [age: 22 +/- 3 y; body mass index (in kg/m(2)): 22.30 +/- 1.83] completed a randomized 2-condition crossover study. During the first night of each 48-h session, subjects had either approximately 8 h (from midnight to 0800) or approximately 4 h (from 0200 to 0600) of sleep. All foods consumed subsequently (jam on buttered toast for breakfast, buffet for lunch, and a free menu for dinner) were eaten ad libitum. Physical activity was recorded by an actimeter. Feelings of hunger, perceived pleasantness of the foods, desire to eat some foods, and sensation of sleepiness were also evaluated.

RESULTS

In comparison with the 8-h sleep session, subjects consumed 559 +/- 617 kcal (ie, 22%) more energy on the day after sleep restriction (P < 0.01), and preprandial hunger was higher before breakfast (P < 0.001) and dinner (P < 0.05). No change in the perceived pleasantness of the foods or in the desire to eat the foods was observed. Physical activity from 1215 to 2015 was higher after sleep restriction than after 8 h of sleep (P < 0.01), even though the sensation of sleepiness was more marked (P < 0.01).

CONCLUSIONS

One night of reduced sleep subsequently increased food intake and, to a lesser extent, estimated physical activity-related energy expenditure in healthy men. These experimental results, if confirmed by long-term energy balance measurements, suggest that sleep restriction could be a factor that promotes obesity. This trial was registered at clinicaltrials.gov as NCT00986492.

Patterns of daily activity and time spent in bed of adult women and adolescent and preadolescent girls from a rural community in Senegal, West Africa

BACKGROUND

In rural Africa, women and adolescent girls sustain a high burden of domestic and agricultural tasks. This could result in energy imbalance and impair their nutritional status.

OBJECTIVE

The aim of the study was to investigate activity during the day and time spent in bed during the night for adult women and adolescent and preadolescent girls living in the same household. The hypothesis was that more prolonged physical inactivity and time spent in bed could be an efficient means for lowering energy expenditure and hence maintaining an adequate nutritional state.

METHODS

Physical activity during the day was qualitatively recorded using 'spot observation' (Super 1989), and quantitatively using accelerometers. A total of 110 females--55 adult women, 45 adolescents and 10 preadolescents--were included in the study. Anthropometric measurements (weight, height and four subcutaneous skinfolds) served as indicators of nutritional status.

RESULTS

Day-to-day reliability of accelerometry counts was acceptable (average intraclass correlation coefficient = 0.73). Differences in daytime activity varied according to age group. Adolescent and preadolescent girls had higher overall activities than adults (p < 0.01). Preadolescent girls went to bed earlier and for longer periods than adult women (p < 0.001). There existed significant relationships between time spent in bed and activity during the day in adult women but not in adolescent or preadolescent girls. A significant relationship between nutritional status and physical activity indices was observed in preadolescent and adolescent girls, but not in women.

CONCLUSIONS

The findings partially support the hypothesis of some compensation of daytime activity by time spent in bed in adult women, but not in adolescent or preadolescent girls.

Short sleep duration and weight gain: a systematic review

OBJECTIVE

The recent obesity epidemic has been accompanied by a parallel growth in chronic sleep deprivation. Physiologic studies suggest sleep deprivation may influence weight through effects on appetite, physical activity, and/or thermoregulation. This work reviews the literature regarding short sleep duration as an independent risk factor for obesity and weight gain.

METHODS AND PROCEDURES

A literature search was conducted for all articles published between 1966 and January 2007 using the search "sleep" and ("duration" or "hour" or "hours") and ("obesity" or "weight") in the MEDLINE database. Additional references were identified by reviewing bibliographies and contacting experts in the field. Studies reporting the association between sleep duration and at least one measure of weight were included.

RESULTS

Thirty-six publications (31 cross-sectional, 5 prospective, and 0 experimental) were identified. Findings in both cross-sectional and cohort studies of children suggested short sleep duration is strongly and consistently associated with concurrent and future obesity. Results from adult cross-sectional analyses were more mixed with 17 of 23 studies supporting an independent association between short sleep duration and increased weight. In contrast, all three longitudinal studies in adults found a positive association between short sleep duration and future weight. This relationship appeared to wane with age.

DISCUSSION

Short sleep duration appears independently associated with weight gain, particularly in younger age groups. However, major study design limitations preclude definitive conclusions. Further research with objective measures of sleep duration, repeated assessments of both sleep and weight, and experimental study designs that manipulate sleep are needed to better define the causal relationship of sleep deprivation on obesity.