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Sleep, nutritional status and eating behavior in children: a review study

ABSTRACT

Objective:

To review the current literature on the relationship between sleep, nutritional status and eating behavior, as well as mechanisms associated with these elements in children.

Data source:

The literature research was conducted in the PubMed, LILACS and Scopus databases, using the following terms: “Child”; “Nutritional status”; “Sleep”; “Physical activity OR Physical activities OR Exercise”. The articles included were those that met the research objective. Review articles, letters to authors, or guidelines were excluded.

Data synthesis:

402 articles were initially found in the literature search. After careful analyses of the title and abstract, and application of inclusion criteria, only 24 studies were included in the present review. Most studies (n=13) suggest that short sleep duration (<9-10 hours/night) is associated with overweight/obesity in children. Only three studies did not show associations between overweight/obesity and sleep variables. Short sleep duration is also associated with poor food quality, higher intake of soft drinks and stimulant beverages before bedtime, as well as micronutrient deficiency.

Conclusions:

Sleep duration is related to overweight and obesity development in infants. Changes in dietary pattern are also related to sleep debt, being one of the mechanisms that contribute to excessive weight gain. It is necessary that health professionals understand the importance of sleep quality in the nutritional status maintenance in children.

Keywords:
Sleep; Nutritional status; Physical activity; Child

RESUMO

Objetivo:

Fazer uma revisão da literatura sobre a relação entre sono, estado nutricional e padrão alimentar, bem como mecanismos associados, na população infantil.

Fontes de dados:

Foram realizadas buscas bibliográficas nas bases PubMed, LILACS e Scopus, usando os seguintes descritores: “Child”; “Nutritional status”; “Sleep”; “Physical activity OR Physical activities OR Exercise”. Os artigos que atenderam ao objetivo da pesquisa foram incluídos. Excluíram-se estudos de revisão, cartas para autores ou diretrizes.

Síntese dos dados:

Inicialmente, 402 artigos foram encontrados na pesquisa. Após análise dos títulos e abstracts e a aplicação dos critérios de exclusão, 24 estudos foram selecionados para a revisão. A maioria dos estudos (n=13) sugere que sono de curta duração (<9-10 horas/noite) está associado com sobrepeso/obesidade na população infantil. Apenas três artigos não reportaram associações entre variáveis do sono e estado nutricional. Curta duração do sono também foi associada a hábitos alimentares ruins, maior consumo de refrigerantes e bebidas estimulantes antes de deitar, bem como deficiência de micronutrientes.

Conclusões:

A duração do sono tem relação com sobrepeso e obesidade na população infantil. Alterações no padrão alimentar também têm relação com débito de sono, sendo um dos mecanismos que contribuem para o ganho de peso excessivo. É necessário que os profissionais de saúde tomem conhecimento da importância da qualidade do sono para a manutenção do estado nutricional em crianças.

Palavras-chave:
Sono; Estado nutricional; Atividade física; Criança

INTRODUCTION

Obesity is a global epidemic that has been affecting all strata of the population, including children and adolescents. The number of overweight/obesity cases among the younger population has grown about ten times in the last four decades, corresponding to around 50 million girls and 74 million boys worldwide.11. Brazil - Organização Pan-Americana de Saúde (OPAS). Obesidade entre crianças e adolescentes aumentou dez vezes em quatro décadas, revela novo estudo do Imperial College London e da OMS. Brasília (DF): OPAS; 2017. A survey conducted in Brazil by the World Health Organization (WHO), in 2016, showed that about 41 million children under five years of age were overweight.22. World Health Organization. Joint child malnutrition estimates - levels and trends. Geneva: WHO; 2017.

The nutritional status of children observed nowadays is the result of changes made in people’s lifestyle in recent decades, especially in young people, with the increased consumption of ultra-processed food, fast-food, and sugar-rich food, associated with a predominance of sedentary activities and the excessive use of electronic equipment.22. World Health Organization. Joint child malnutrition estimates - levels and trends. Geneva: WHO; 2017. In addition to these factors, sleep quality has been associated with nutritional status.33. Cappuccio FP, Taggart FM, Kandala NB, Currie A, Peile E, Stranges S, et al. Meta-analysis of short sleep duration and obesity in children and adults. Sleep. 2008;31:619-26. https://doi.org/10.1093/sleep/31.5.619
https://doi.org/https://doi.org/10.1093/...

Several studies have shown the association between sleep duration and the development of obesity in adults and children33. Cappuccio FP, Taggart FM, Kandala NB, Currie A, Peile E, Stranges S, et al. Meta-analysis of short sleep duration and obesity in children and adults. Sleep. 2008;31:619-26. https://doi.org/10.1093/sleep/31.5.619
https://doi.org/https://doi.org/10.1093/...
. Although the mechanisms involved are uncertain, some possible pathways might explain this causal relationship, including changes in hormonal production, physical activity level, and eating behavior.33. Cappuccio FP, Taggart FM, Kandala NB, Currie A, Peile E, Stranges S, et al. Meta-analysis of short sleep duration and obesity in children and adults. Sleep. 2008;31:619-26. https://doi.org/10.1093/sleep/31.5.619
https://doi.org/https://doi.org/10.1093/...
,44. Miller AM, Kruisbrink M, Wallace J, Ji C, Cappuccio FP. Sleep duration and incidence of obesity in infants, children, and adolescents: a systematic review and meta-analysis of prospective studies. Sleep. 2018;41:1-19. https://doi.org/10.1093/sleep/zsy018
https://doi.org/https://doi.org/10.1093/...
,55. Sharma S, Kavuru M. Sleep and metabolism: an overview. Int J Endocrinol. 2010;2010:270832. https://doi.org/10.1155/2010/270832
https://doi.org/https://doi.org/10.1155/...

The sleep debt might influence both sides of energy balance, resulting in increased energy intake and lower energy expenditure. As a consequence of fatigue caused by sleep loss, lower energy expenditure during the day is observed, which leads to a sedentary behavior.66. Marques G, Matos M, Afonso C, Conceição AP, Martins T, Pinto S, et al. Childhood obesity and reduction of hours of sleep: results from cross-sectional study. Mundo Saúde. 2018;42:811-22. https://doi.org/10.15343/0104-7809.20184204811822
https://doi.org/https://doi.org/10.15343...
In addiction, higher energy intake and higher intake of palatable foods, such as sugar and fat-rich food, are seen in response to sleep debt.77. King C. Soft drinks consumption and child behaviour problems: the role of food insecurity and sleep patterns. Public Health Nutr. 2017;20:266-73. https://doi.org/10.1017/s1368980016002093
https://doi.org/https://doi.org/10.1017/...
In adults, sleep restriction has been associated with changes in hormonal regulators of energy balance, such as increased ghrelin and decreased leptin secretion.88. Spiegel K, Tasali E, Penev P, Van Cauter E. Brief communication: sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Ann Intern Med. 2004;141:846-50. https://doi.org/10.7326/0003-4819-141-11-200412070-00008
https://doi.org/https://doi.org/10.7326/...
In children, short sleep duration has been associated with higher energy intake in early life99. Fisher A, McDonald L, Jaarsveld CH, Llewellyn C, Fildes A, Schrempft S, et al. Sleep and energy intake in early childhood. Int J Obes (Lond). 2014;38:926-9. https://doi.org/10.1038/ijo.2014.50
https://doi.org/https://doi.org/10.1038/...
and hedonic eating.1010. McDonald L, Wardle J, Llewellyn CH, Fisher A. Nighttime sleep duration and hedonic eating in childhood. Int J Obes (Lond). 2015;39:1463-6. https://doi.org/10.1038/ijo.2015.132
https://doi.org/https://doi.org/10.1038/...
Also, insulin resistance and increased cortisol levels are seen in association with sleep debt.1111. Donga E, Vandijk JG, Biermasz NR, Lammers GJ, Van Kralingen KW, Corssmit EP, et al. A single night of partial sleep deprivation induces insulin resistance in multiple metabolic pathways in healthy subjects. J Clin Endocrinol Metab. 2010;95:2963-8. https://doi.org/10.1210/jc.2009-2430
https://doi.org/https://doi.org/10.1210/...
The insulin resistance might alter lipid profile and increase metabolic risk in children and adolescents, especially when associated with overweight and physical inactivity.1212. Rosa G, Mello DB, Fortes MS, Dantas EH. Adipose tissue, metabolic hormones and physical exercise. Rev Andal Med Deporte. 2013;6:78-84.

Thus, this study aims to review the literature about the relationship between sleep and nutritional status in children, as well as discuss the mechanisms associated with this relationship in this population.

METHOD

The present study represents an integrative review. The guiding question was: what is the relationship between sleep deprivation, nutritional status, and physical activity level in children? This research question was based in PI(E)COS formulation, in which: Population=children; Intervention or exposure=sleep duration; Comparison=any; Outcomes=nutritional status. The steps taken to construct the research are described below.

Bibliographic research was carried out in the PubMed, LILACS and Scopus databases, using the descriptors indicated by Medical Subject Headings (MeSH): “Child”; “Nutritional status”; “Sleep”; “Physical activity OR Physical activities OR Exercise”. Articles in Portuguese, English and Spanish, published until 2019, were included.

Reviewed studies were selected according to the following inclusion criteria:

  1. Children population;

  2. Non-inclusion of subjects with any sleep disorder (e.g., obstructive sleep apnea, insomnia, restless legs syndrome, etc.) or who were using appetite-suppressing medications;

  3. Evaluation of the relationship between sleep and nutritional status, dietary pattern or level of physical activity. Review articles (systematic, integrative, narrative) and letters to authors were excluded.

In order to select the studies, the following steps were taken: first, the title and abstracts were analyzed and articles that didn’t match our inclusion criteria were excluded; second, the selected articles were read in full to identify possible exclusion criteria and duplicated studies; and third, data was extracted using a Microsoft Excel spreadsheet, containing information such as authors’ names, article title, published journal and year of publication, objective, keywords and main results.

Quality analysis was performed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies from the National Institutes of Health (NIH).1313. National Heart Lung and Blood Institute [homepage on the Internet]. Quality assessment tool for observational cohort and cross-sectional studies - NHLBI, NIH. National Institutes of Health; 2014 [cited 2020 Jun 5]. Available from: Available from: https://www.nhlbi.nih.gov/health-topics/study-qualityassessment-tools
https://www.nhlbi.nih.gov/health-topics/...
Also, the compliance of each study was checked by the Strengthening the Reporting of Observational Studies in Epidemiology association (STROBE).1414. Elm EV, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The strengthening the reporting of observational studies in epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol. 2008;61:344e9. https://doi.org/10.1016/j.jclinepi.2007.11.008
https://doi.org/https://doi.org/10.1016/...

RESULTS

As shown in Figure 1, 402 articles were initially found in the literature search: 196 from the PubMed database, 22 from the LILACS database, and 184 from the Scopus database. After screening by title and abstract, 193 articles were excluded for not attending to our research question. After reading full-text articles, 98 were excluded for not attending to the inclusion criteria, 87 articles were excluded as duplicated, and two were not found in full. Therefore, only 23 articles were included in the present review.

Figure 1
Flowchart of study selection.

The analyzed studies were published between 2002 and 2019; 22 of them were cross-sectional and one of them was longitudinal. The majority of analyzed studies (n=13) suggests that short sleep duration (<9-10 hours/night) is associated with overweight/obesity and nutritional status in the infant population; 8 of them (34.7%) point out that sleep duration is related to eating behavior.

Sleep was objectively evaluated by polysomnography in only one study;1515. Chamorro R, Ferri R, Algarín C, Garrido M, Lozoff B, Peirano P. Sleep cyclic alternating pattern in otherwise healthy overweight school-age children. Sleep. 2014;37:557-60. https://doi.org/10.5665/sleep.3496
https://doi.org/https://doi.org/10.5665/...
all others used questionnaires to assess sleep duration and quality. The questionnaires used were either developed by the authors (n=16) or validated sleep questionnaires, such as the Pediatric Sleep Questionnaire (PSQI; n=3), the Children Sleep Habit Questionnaire (CSHQ; n=1), the Sleep Disturbance Scale for Children (SDSC; n=1) and the Brief Infant Sleep Questionnaire (BISQ; n=1). The mean age of the studied population ranged from 6 months to 18 years. Tables 1, 2 and 3 present a brief description of the included studies.

Table 1
Description and main results of the included studies with children between six months and eight years old.

Table 2
Description and main results of the included studies with children between six and ten years old.

Table 3
Description and main results of the included studies with children and adolescents.

From our search, 16 studies investigated the relationship between nutritional status and sleep pattern. Most of the studies found some association between nutritional status and sleep loss. On average, sleeping less than 10-9 hours was associated with overweight/obesity or a higher incidence of obesity was found in short-sleepers.66. Marques G, Matos M, Afonso C, Conceição AP, Martins T, Pinto S, et al. Childhood obesity and reduction of hours of sleep: results from cross-sectional study. Mundo Saúde. 2018;42:811-22. https://doi.org/10.15343/0104-7809.20184204811822
https://doi.org/https://doi.org/10.15343...
,1515. Chamorro R, Ferri R, Algarín C, Garrido M, Lozoff B, Peirano P. Sleep cyclic alternating pattern in otherwise healthy overweight school-age children. Sleep. 2014;37:557-60. https://doi.org/10.5665/sleep.3496
https://doi.org/https://doi.org/10.5665/...
,1616. Carrillo-Larco RM, Bernabé-Ortiz A, Miranda JJ. Short sleep duration and childhood obesity: cross-sectional analysis in Peru and patterns in four developing countries. PLoS One. 2014;9:e112433. https://doi.org/10.1371/journal.pone.0112433
https://doi.org/https://doi.org/10.1371/...
,1717. Agüero SD, Rivera PH. Association between the amount of sleep and obesity in Chilean schoolchildren. Arch Argent Pediatr. 2016;114:114-9. https://doi.org/10.5546/aap.2016.eng.114
https://doi.org/https://doi.org/10.5546/...
,1818. Bazán AM, Sellán MC, Vázquez AS, Díaz ML, Domínguez FS. Factors associated with overweight and childhood obesity in Spain according to the latest national health survey (2011). Esc Anna Nery Rev Enferm. 2018;22:e20170321. https://doi.org/10.1590/2177-9465-ean-2017-0321
https://doi.org/https://doi.org/10.1590/...
,1919. Agüero DS, Giraldo GS, Guerra JB. Relationship between nutritional status and sleep duration in Chilean school-age children. ALAN. 2017;67:1-5.,2020. Cicek B, Ozturk A, Mazicioglu MM, Elmali F, Turp N, Kurtoglu S. The risk analysis of arm fat area in Turkish children and adolescents. Ann Hum Biol. 2009;36:28-37. https://doi.org/10.1080/03014460802537690
https://doi.org/https://doi.org/10.1080/...
,2121. Jiang YR, Spruyt K, Chen WJ, Shen XM, Jiang F. Somatic growth of lean children: the potential role of sleep. World J Pediatr. 2014;10:245-50. https://doi.org/10.1007/s12519-014-0500-2
https://doi.org/https://doi.org/10.1007/...
,2222. Katsa ME, Ioannidis A, Zyga S, Tsironi M, Koutsovitis P, Chatzipanagiotou S, et al. The effect of nutrition and sleep habits on predisposition for metabolic syndrome in Greek children. J Pediatr Nurs. 2018;40:e2-8. https://doi.org/10.1016/j.pedn.2018.01.012
https://doi.org/https://doi.org/10.1016/...
,2323. Guo X, Zheng L, Li Y, Yu S, Sun G, Yang H, et al. Differences in lifestyle behaviors, dietary habits, and familial factors among normal-weight, overweight, and obese Chinese children and adolescents. Int J Behav Nutr Phys Act. 2012;9:120. https://doi.org/10.1186/1479-5868-9-120
https://doi.org/https://doi.org/10.1186/...
,2424. Corso AC, Caldeira GV, Fiates GM, Schmitz BA, Ricardo GD, Vasconcelos FA. Behavioral factors associated with overweight and with obesity in students in the State of Santa Catarina. Rev Bras Estud Popul. 2012;29:117-31. https://doi.org/10.1590/s0102-30982012000100008
https://doi.org/https://doi.org/10.1590/...
,2525. Durán AS, Fuentes NC, Vásquez SQ, Cediel GG, Díaz VN. Relationship between nutritional status and sleep in school children from the San Miguel commune, Santiago, Chile. Rev Chil Nutr. 2012;39:30-7. https://doi.org/10.4067/s0717-75182012000100003
https://doi.org/https://doi.org/10.4067/...
,2626. Jong E, Stocks T, Visscher TL, HiraSing RA, Seidell JC, Renders CM. Association between sleep duration and overweight: the importance of parenting. Int J Obes (Lond). 2012;36:1278-84. https://doi.org/10.1038/ijo.2012.119
https://doi.org/https://doi.org/10.1038/...

In a cross-sectional study conducted with 1,810 children aged between 6 and 11 years, sleep quality was evaluated by the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and the results showed that 49.9% of the evaluated children slept less than recommended (<10 hours a day), and this sleep restriction was higher during weekdays and among older children. Shorter sleep time was considered a risk factor for overweight/obesity development.1717. Agüero SD, Rivera PH. Association between the amount of sleep and obesity in Chilean schoolchildren. Arch Argent Pediatr. 2016;114:114-9. https://doi.org/10.5546/aap.2016.eng.114
https://doi.org/https://doi.org/10.5546/...

In Brazil, a cross-sectional study with 4,964 elementary school students indicated the prevalence of 15.4% of overweight and 6.0% of obesity, which was associated with reduced sports practice, shorter sleep duration/night, and longer time using the computer.2424. Corso AC, Caldeira GV, Fiates GM, Schmitz BA, Ricardo GD, Vasconcelos FA. Behavioral factors associated with overweight and with obesity in students in the State of Santa Catarina. Rev Bras Estud Popul. 2012;29:117-31. https://doi.org/10.1590/s0102-30982012000100008
https://doi.org/https://doi.org/10.1590/...

Only Chamorro et al.1515. Chamorro R, Ferri R, Algarín C, Garrido M, Lozoff B, Peirano P. Sleep cyclic alternating pattern in otherwise healthy overweight school-age children. Sleep. 2014;37:557-60. https://doi.org/10.5665/sleep.3496
https://doi.org/https://doi.org/10.5665/...
used the gold standard method of polysomnography to evaluate sleep. The study compared sleep structure in normal and overweight ten year old children. The authors observed that there was an inverse relationship between body mass index (BMI) and sleep duration, and overweight children showed reduced sleep duration, efficiency, and an atypical sleep cycle during the night, with reduced stage 3 non-rapid eye movement (NREM) sleep at the beginning of the night, and increased stage 3 NREM sleep at late night.

Other anthropometrical parameters besides body weight and BMI were associated with sleep duration. Cicek et al.,2020. Cicek B, Ozturk A, Mazicioglu MM, Elmali F, Turp N, Kurtoglu S. The risk analysis of arm fat area in Turkish children and adolescents. Ann Hum Biol. 2009;36:28-37. https://doi.org/10.1080/03014460802537690
https://doi.org/https://doi.org/10.1080/...
in a sample of 5,358 children and adolescents from 6 to 17 years old, found a positive association between arm fat area and sleep duration below eight hours.

Katsa et al.,2222. Katsa ME, Ioannidis A, Zyga S, Tsironi M, Koutsovitis P, Chatzipanagiotou S, et al. The effect of nutrition and sleep habits on predisposition for metabolic syndrome in Greek children. J Pediatr Nurs. 2018;40:e2-8. https://doi.org/10.1016/j.pedn.2018.01.012
https://doi.org/https://doi.org/10.1016/...
in a study that investigated life habits and predisposition to metabolic syndrome in children between 5 and 12 years old, found that late bedtime is positively related to weight, lower length, and waist circumference. They also found associations between late bedtime, blood glucose and diastolic blood pressure.

In contrast, Christoph et al.2727. Christoph MJ, Grigsby-Toussaint DS, Baingana R, Ntambi JM. Physical activity, sleep, and BMI percentile in rural and urban Ugandan youth. Ann Glob Health. 2017;83:311-9. https://doi.org/10.1016/j.aogh.2017.04.005
https://doi.org/https://doi.org/10.1016/...
, in a study in Africa, with 146 adolescents between 11 and 16 years old, showed that BMI was positively associated with sleep quality. They also found a positive association between BMI and being more physically active. Aravena et al.2828. Aravena P, Mansilla A, Pangue A, Needham V, Muñoz C. Nutritional status and hours of sleep among elementary school students in the city of Punta arenas in 2016. Rev Chil Nutr. 2017;44:270-5. https://doi.org/10.4067/s0717-75182017000300270
https://doi.org/https://doi.org/10.4067/...
failed to find an association between sleep and nutritional status. However, they found that, during weekdays, the percentage of obese children who sleep the recommended hours was 69.2%, less than that of overweight children (73.5%) and children with normal weight (75%) (p=0.215). On weekend days, the percentage of normal weight children that slept the recommended hours was 63%, while that percentage was 65.7% in the obese group and 68.4% in the overweight group (p=0.781). Also, Giovaninni et al.2929. Giovaninni NP, Fuly JT, Moraes LI, Coutinho TN, Trarbach EB, Jorge AA, et al. Study of the association between 3111T/C polymorphism of the CLOCK gene and the presence of overweight in schoolchildren. Pediatria. 2014;90:500-5. https://doi.org/10.1016/j.jped.2014.01.011
https://doi.org/https://doi.org/10.1016/...
, in a cross-sectional study with 370 children and adolescents between 6 and 13 years, found that sleep duration was inversely related to age (p<0.001), but found only a trend toward a higher prevalence of overweight in children who slept less than nine hours (23%) when compared to those who slept more than ten hours (16%, p=0.06).

Regarding food patterns, we found eight studies that investigated associations between sleep and food habits or behavior. Fewer hours of sleep and late bedtime have shown to be related to a poor quality diet.

Golley et al.,3030. Golley RK, Maher CA, Matricciani L, Olds TS. Sleep duration or bedtime? Exploring the association between sleep timing behaviour, diet and BMI in children and adolescents. Int J Obes (Lond). 2013;37:546-51. https://doi.org/10.1038/ijo.2012.212
https://doi.org/https://doi.org/10.1038/...
in a study with 2,200 Australian children, concluded that early bedtime is associated with better diet quality and higher intake of fruits and vegetables, and that those who showed a late bedtime presented high consumption of poor quality food.

Higher intake of fast-food and soft drinks was observed in children with short sleep duration (<9 hours/night) in the Kiel Obesity Prevention Study.3131. Hitze B, Bosy-Westphal A, Bielfeldt F, Settler U, Plachta-Danielzik S, Pfeuffer M, et al. Determinants and impact of sleep duration in children and adolescents: data of the Kiel Obesity Prevention Study. Eur J Clin Nutr. 2009;63:739-46. https://doi.org/10.1038/ejcn.2008.41
https://doi.org/https://doi.org/10.1038/...
King et al.77. King C. Soft drinks consumption and child behaviour problems: the role of food insecurity and sleep patterns. Public Health Nutr. 2017;20:266-73. https://doi.org/10.1017/s1368980016002093
https://doi.org/https://doi.org/10.1017/...
also showed a higher intake of soft drinks in children under food insecurity with sleep difficulties. In the study of Na et al.,3232. Na M, Eagleton SG, Jomaa L, Lawton K, Savage JS. Food insecurity is associated with suboptimal sleep quality, but not sleep duration, among low-income head start children of pre-school age. Public Health Nutr. 2019;23:701-10. https://doi.org/10.1017/s136898001900332x
https://doi.org/https://doi.org/10.1017/...
food insecurity was associated with poor sleep quality. Jong et al.2626. Jong E, Stocks T, Visscher TL, HiraSing RA, Seidell JC, Renders CM. Association between sleep duration and overweight: the importance of parenting. Int J Obes (Lond). 2012;36:1278-84. https://doi.org/10.1038/ijo.2012.119
https://doi.org/https://doi.org/10.1038/...
investigated some determinants of short sleep duration. The eating habits associated with short sleep duration varied across ages and sex, but, overall, eating sweetened food, a lack of an eating routine and watching TV during the meal was associated with short sleep duration.

The consumption of stimulant drinks, such as chocolate milk, soft drinks, coffee and black tea at night contribute to a 2.6 higher risk for sleep disturbance and influence sleep quality in children between seven and eight years old.3434. Kordas K, Casavantes KM, Mendoza C, Lopez P, Ronquillo D, Rosado JL, et al. The association between lead and micronutrient status, and children’s sleep, classroom behavior, and activity. Arch Environ Occup Health. 2007;62:105-12. https://doi.org/10.3200/aeoh.62.2.105-112
https://doi.org/https://doi.org/10.3200/...
Micronutrient deficiency also showed a relation to sleep patterns. In the studies done by Kordas et al.,3434. Kordas K, Casavantes KM, Mendoza C, Lopez P, Ronquillo D, Rosado JL, et al. The association between lead and micronutrient status, and children’s sleep, classroom behavior, and activity. Arch Environ Occup Health. 2007;62:105-12. https://doi.org/10.3200/aeoh.62.2.105-112
https://doi.org/https://doi.org/10.3200/...
,3535. Kordas K, Siegel EH, Olney DK, Katz J, Tielsch JM, Chwaya HM, et al. Maternal reports of sleep in 6-18-month-old infants from Nepal and Zanzibar: association with iron deficiency anemia and stunting. Early Hum Dev. 2008;84:389-98. https://doi.org/10.1016/j.earlhumdev.2007.10.007
https://doi.org/https://doi.org/10.1016/...
iron-deficient children showed sleep disruptions, such as early wake up, increased sleep latency, sleep fragmentation, and reduction in sleep duration.

The quality of the studies included in our review was checked by the NIH tool.1313. National Heart Lung and Blood Institute [homepage on the Internet]. Quality assessment tool for observational cohort and cross-sectional studies - NHLBI, NIH. National Institutes of Health; 2014 [cited 2020 Jun 5]. Available from: Available from: https://www.nhlbi.nih.gov/health-topics/study-qualityassessment-tools
https://www.nhlbi.nih.gov/health-topics/...
The studies of Guo et al.2323. Guo X, Zheng L, Li Y, Yu S, Sun G, Yang H, et al. Differences in lifestyle behaviors, dietary habits, and familial factors among normal-weight, overweight, and obese Chinese children and adolescents. Int J Behav Nutr Phys Act. 2012;9:120. https://doi.org/10.1186/1479-5868-9-120
https://doi.org/https://doi.org/10.1186/...
and Durán et al.2525. Durán AS, Fuentes NC, Vásquez SQ, Cediel GG, Díaz VN. Relationship between nutritional status and sleep in school children from the San Miguel commune, Santiago, Chile. Rev Chil Nutr. 2012;39:30-7. https://doi.org/10.4067/s0717-75182012000100003
https://doi.org/https://doi.org/10.4067/...
had the lowest score in the quality analysis, and were considered poor, with six positive answers (in a total of 14) in the NIH tool. Most of the studies were considered fair and had between seven and nine positive answers in the NIH tool (King et al.,77. King C. Soft drinks consumption and child behaviour problems: the role of food insecurity and sleep patterns. Public Health Nutr. 2017;20:266-73. https://doi.org/10.1017/s1368980016002093
https://doi.org/https://doi.org/10.1017/...
Kordas et al.,3434. Kordas K, Casavantes KM, Mendoza C, Lopez P, Ronquillo D, Rosado JL, et al. The association between lead and micronutrient status, and children’s sleep, classroom behavior, and activity. Arch Environ Occup Health. 2007;62:105-12. https://doi.org/10.3200/aeoh.62.2.105-112
https://doi.org/https://doi.org/10.3200/...
Christoph et al.,2727. Christoph MJ, Grigsby-Toussaint DS, Baingana R, Ntambi JM. Physical activity, sleep, and BMI percentile in rural and urban Ugandan youth. Ann Glob Health. 2017;83:311-9. https://doi.org/10.1016/j.aogh.2017.04.005
https://doi.org/https://doi.org/10.1016/...
Katsa et al.,2222. Katsa ME, Ioannidis A, Zyga S, Tsironi M, Koutsovitis P, Chatzipanagiotou S, et al. The effect of nutrition and sleep habits on predisposition for metabolic syndrome in Greek children. J Pediatr Nurs. 2018;40:e2-8. https://doi.org/10.1016/j.pedn.2018.01.012
https://doi.org/https://doi.org/10.1016/...
Carrillo-Larco et al.,1616. Carrillo-Larco RM, Bernabé-Ortiz A, Miranda JJ. Short sleep duration and childhood obesity: cross-sectional analysis in Peru and patterns in four developing countries. PLoS One. 2014;9:e112433. https://doi.org/10.1371/journal.pone.0112433
https://doi.org/https://doi.org/10.1371/...
Kordas et al.,3535. Kordas K, Siegel EH, Olney DK, Katz J, Tielsch JM, Chwaya HM, et al. Maternal reports of sleep in 6-18-month-old infants from Nepal and Zanzibar: association with iron deficiency anemia and stunting. Early Hum Dev. 2008;84:389-98. https://doi.org/10.1016/j.earlhumdev.2007.10.007
https://doi.org/https://doi.org/10.1016/...
Jiang et al.,2121. Jiang YR, Spruyt K, Chen WJ, Shen XM, Jiang F. Somatic growth of lean children: the potential role of sleep. World J Pediatr. 2014;10:245-50. https://doi.org/10.1007/s12519-014-0500-2
https://doi.org/https://doi.org/10.1007/...
Jong et al.,2626. Jong E, Stocks T, Visscher TL, HiraSing RA, Seidell JC, Renders CM. Association between sleep duration and overweight: the importance of parenting. Int J Obes (Lond). 2012;36:1278-84. https://doi.org/10.1038/ijo.2012.119
https://doi.org/https://doi.org/10.1038/...
Hitze et al.,3131. Hitze B, Bosy-Westphal A, Bielfeldt F, Settler U, Plachta-Danielzik S, Pfeuffer M, et al. Determinants and impact of sleep duration in children and adolescents: data of the Kiel Obesity Prevention Study. Eur J Clin Nutr. 2009;63:739-46. https://doi.org/10.1038/ejcn.2008.41
https://doi.org/https://doi.org/10.1038/...
Chamorro et al.,1515. Chamorro R, Ferri R, Algarín C, Garrido M, Lozoff B, Peirano P. Sleep cyclic alternating pattern in otherwise healthy overweight school-age children. Sleep. 2014;37:557-60. https://doi.org/10.5665/sleep.3496
https://doi.org/https://doi.org/10.5665/...
Ruotolo et al.,3333. Ruotolo F, Prado LB, Ferreira VR, Prado GF, Carvalho LB. Intake of stimulant foods is associated with development of parasomnias in children. Arq Neuropsiquiatr. 2016;74:62-6. https://doi.org/10.1590/0004-282x20150193
https://doi.org/https://doi.org/10.1590/...
Cicek et al.,2020. Cicek B, Ozturk A, Mazicioglu MM, Elmali F, Turp N, Kurtoglu S. The risk analysis of arm fat area in Turkish children and adolescents. Ann Hum Biol. 2009;36:28-37. https://doi.org/10.1080/03014460802537690
https://doi.org/https://doi.org/10.1080/...
Agüero et al.,1919. Agüero DS, Giraldo GS, Guerra JB. Relationship between nutritional status and sleep duration in Chilean school-age children. ALAN. 2017;67:1-5. Durán et al.,2525. Durán AS, Fuentes NC, Vásquez SQ, Cediel GG, Díaz VN. Relationship between nutritional status and sleep in school children from the San Miguel commune, Santiago, Chile. Rev Chil Nutr. 2012;39:30-7. https://doi.org/10.4067/s0717-75182012000100003
https://doi.org/https://doi.org/10.4067/...
Corso et al.,2424. Corso AC, Caldeira GV, Fiates GM, Schmitz BA, Ricardo GD, Vasconcelos FA. Behavioral factors associated with overweight and with obesity in students in the State of Santa Catarina. Rev Bras Estud Popul. 2012;29:117-31. https://doi.org/10.1590/s0102-30982012000100008
https://doi.org/https://doi.org/10.1590/...
Bazán et al.,1818. Bazán AM, Sellán MC, Vázquez AS, Díaz ML, Domínguez FS. Factors associated with overweight and childhood obesity in Spain according to the latest national health survey (2011). Esc Anna Nery Rev Enferm. 2018;22:e20170321. https://doi.org/10.1590/2177-9465-ean-2017-0321
https://doi.org/https://doi.org/10.1590/...
Marques et al.,66. Marques G, Matos M, Afonso C, Conceição AP, Martins T, Pinto S, et al. Childhood obesity and reduction of hours of sleep: results from cross-sectional study. Mundo Saúde. 2018;42:811-22. https://doi.org/10.15343/0104-7809.20184204811822
https://doi.org/https://doi.org/10.15343...
Aravena et al.,2828. Aravena P, Mansilla A, Pangue A, Needham V, Muñoz C. Nutritional status and hours of sleep among elementary school students in the city of Punta arenas in 2016. Rev Chil Nutr. 2017;44:270-5. https://doi.org/10.4067/s0717-75182017000300270
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Giovaninni et al.2929. Giovaninni NP, Fuly JT, Moraes LI, Coutinho TN, Trarbach EB, Jorge AA, et al. Study of the association between 3111T/C polymorphism of the CLOCK gene and the presence of overweight in schoolchildren. Pediatria. 2014;90:500-5. https://doi.org/10.1016/j.jped.2014.01.011
https://doi.org/https://doi.org/10.1016/...
), and the highest quality studies were the ones made by Agüero and Riveira,1717. Agüero SD, Rivera PH. Association between the amount of sleep and obesity in Chilean schoolchildren. Arch Argent Pediatr. 2016;114:114-9. https://doi.org/10.5546/aap.2016.eng.114
https://doi.org/https://doi.org/10.5546/...
Golley et al.3030. Golley RK, Maher CA, Matricciani L, Olds TS. Sleep duration or bedtime? Exploring the association between sleep timing behaviour, diet and BMI in children and adolescents. Int J Obes (Lond). 2013;37:546-51. https://doi.org/10.1038/ijo.2012.212
https://doi.org/https://doi.org/10.1038/...
and Na et al.,3232. Na M, Eagleton SG, Jomaa L, Lawton K, Savage JS. Food insecurity is associated with suboptimal sleep quality, but not sleep duration, among low-income head start children of pre-school age. Public Health Nutr. 2019;23:701-10. https://doi.org/10.1017/s136898001900332x
https://doi.org/https://doi.org/10.1017/...
with ten positive answers. The compliance with the STROBE checklist showed that only three studies fulfilled more than 75% (Agüero et al.,1919. Agüero DS, Giraldo GS, Guerra JB. Relationship between nutritional status and sleep duration in Chilean school-age children. ALAN. 2017;67:1-5. Chamorro et al.1515. Chamorro R, Ferri R, Algarín C, Garrido M, Lozoff B, Peirano P. Sleep cyclic alternating pattern in otherwise healthy overweight school-age children. Sleep. 2014;37:557-60. https://doi.org/10.5665/sleep.3496
https://doi.org/https://doi.org/10.5665/...
and King et al.77. King C. Soft drinks consumption and child behaviour problems: the role of food insecurity and sleep patterns. Public Health Nutr. 2017;20:266-73. https://doi.org/10.1017/s1368980016002093
https://doi.org/https://doi.org/10.1017/...
) of the items of the checklist, and the others accomplished between 43.7 and 71.8%. The main issues found were an inadequate description of sample size and efforts to address the potential source of bias, treatment of missing data, discussion of limitations and generalizability of the study results.

DISCUSSION

Sleep is defined as the moment of complete rest in which there is a decrease in consciousness, reduction of muscle movements, and slowing of the body. It has a restorative function and is the time when memory consolidation occurs. In addition, it plays a critical role in brain functions, such as mood regulation and cognitive performance, and is critically involved in regulating metabolism, acting in appetite control, immunological functions, among others.3636. Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, et al. 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. Sleep. 2015;11:931-52. https://doi.org/10.5664/jcsm.4950
https://doi.org/https://doi.org/10.5664/...

Sleep is classified into two different phases. NREM (non-rapid eye movement) sleep is when physical rest occurs, and is related to the immune system and the rhythm of the digestive system function. Throughout NREM sleep, three sleep stages are passed, progressing from more superficial sleep to slow-wave sleep, a deeper sleep stage. In the NREM sleep stage 1, there is a transition from the waking state to sleep; this is the lightest stage of sleep. In the second phase, NREM sleep stage 2, eye movements stop and deepest sleep begins. In the third and final phase, NREM sleep stage 3, known as slow-wave sleep or deep sleep, awakening becomes more difficult, there is a decrease in muscle tone and hormonal secretion, such as growth hormone (GH).3636. Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, et al. 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. Sleep. 2015;11:931-52. https://doi.org/10.5664/jcsm.4950
https://doi.org/https://doi.org/10.5664/...
,3737. Sleep Foundation [homepage on the Internet]. Stages of sleep [cited 2020 Apr 7]. Available from: Available from: https://www.sleepfoundation.org/how-sleep-works/stages-of-sleep
https://www.sleepfoundation.org/how-slee...

In REM (rapid eye movement) sleep, psychological rest, emotional well-being, and memory consolidation occurs. REM sleep is also known as the dream phase, due to increased brain activity. At this stage, there is a decrease in muscle tone, increased heart rate, and irregular breathing.3737. Sleep Foundation [homepage on the Internet]. Stages of sleep [cited 2020 Apr 7]. Available from: Available from: https://www.sleepfoundation.org/how-sleep-works/stages-of-sleep
https://www.sleepfoundation.org/how-slee...
,3838. Sleep Foundation [homepage on the Internet]. What happens when you sleep? [cited 2020 Apr 7]. Available from: Available from: https://www.sleepfoundation.org/articles/what-happens-when-you-sleep
https://www.sleepfoundation.org/articles...
,3939. Rodrigues YT, Rodrigues PP. Maturação dos fenômenos cronobiológicos na infância. In: Jansen JM, Lopes AJ, Jansen U, Capone D, Maeda TY, Noronha A, et al, editors. Medicina da noite: da cronobiologia à prática clínica. Rio de Janeiro (RJ): FIOCRUZ; 2007.

During the first year of life, there are several changes in the sleep architecture until NREM and REM sleep stages are consolidated. During pregnancy, the fetus is influenced by maternal circadian rhythm, and, after birth, a period of adaptation is required until sleep-wake cycle is established.4040. Colten HR, Altevogt BM, editors. Sleep disorders and sleep deprivation: an unmet public health problem. Washington (DC): National Academies Press (US); 2006.

In the first three months of life, a newborn sleeps about 16 to 18 hours a day. In this stage of life, three phases of sleep are seen: quiet sleep (similar to NREM sleep), active sleep (similar to REM sleep), and indeterminate sleep. The sleep onset occurs in REM sleep, and each episode consists of only 1 or 2 cycles, which is the result of the lack of establishment of the circadian rhythm.4141. Paruthi S, Brooks LJ, D’Ambrosio C, Hall WA, Kotagal S, Lloyd RM, et al. Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine. J Clin Sleep Med. 2016;12:785-6. https://doi.org/10.5664/jcsm.5866
https://doi.org/https://doi.org/10.5664/...

After three months of age, waking time during the day increases and longer periods of sleep at night are observed, due to the beginning of hormonal cycling of cortisol and melatonin. These hormones are responsible for circadian rhythm control regulated by environmental stimuli (breastfeeding routines and bedtime). At this stage, the sleep cycles of NREM and REM become more regular.4141. Paruthi S, Brooks LJ, D’Ambrosio C, Hall WA, Kotagal S, Lloyd RM, et al. Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine. J Clin Sleep Med. 2016;12:785-6. https://doi.org/10.5664/jcsm.5866
https://doi.org/https://doi.org/10.5664/...

At 12 months of age, the child sleeps about 12 to 16 hours a day, with most of the sleep consolidated in the night and some naps during the day. Studies suggest that children spend more time in REM sleep when compared to adolescents.4141. Paruthi S, Brooks LJ, D’Ambrosio C, Hall WA, Kotagal S, Lloyd RM, et al. Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine. J Clin Sleep Med. 2016;12:785-6. https://doi.org/10.5664/jcsm.5866
https://doi.org/https://doi.org/10.5664/...
,4242. American Academy of Pediatrics [homepage on the Internet]. Supports Childhood Sleep Guidelines. Itasca, IL: APP; 2016 [cited 2020 Apr 08]. Available from: Available from: https://www.aappublications.org/news/2016/06/13/Sleep061316
https://www.aappublications.org/news/201...

Over the years, the sleep duration seems to decrease in the child population in several countries. Between 1905 and 2008, there was an average reduction of 75 minutes in sleep duration in this population.4343. Matricciani L, Olds T, Petkov J. In search of lost sleep: secular trends in the sleep time of school-aged children and adolescents. Sleep Med Rev. 2012;16:203-11. https://doi.org/10.1016/j.smrv.2011.03.005
https://doi.org/https://doi.org/10.1016/...
Changes in sleep patterns were accompanied by lifestyle changes, such as the use of electronic equipment (tablets, mobile phones, computers, television, etc.). The overuse of this equipment has been related to sleep duration and quality.4444. Sijtsma A, Koller M, Sauer PJ, Corpeleijn E. Television, sleep, outdoor play and BMI in young children: the GECKO Drenthe cohort. Eur J Pediatr. 2015;174:631-9. https://doi.org/10.1007/s00431-014-2443-y
https://doi.org/https://doi.org/10.1007/...

Studies suggest that the presence of screens in the bedroom is associated with a decrease in sleep time, due to a greater propensity to use these equipments.4545. El Halal C, Nunes ML. Sleep and weight-height development. J Pediatr. 2018;95(Suppl 1):S2-9. https://doi.org/10.1016/j.jped.2018.10.009
https://doi.org/https://doi.org/10.1016/...
A study conducted in the United States, with 48,687 children of the National Survey of Children’s Health, showed that the presence of a television in the bedroom was associated with insufficient sleep for more than four nights per week.4646. Sisson SB, Broyles ST, Newton RL Jr, Baker BL, Chernausek SD. TVs in the bedrooms of children: does it impact health and behavior? Prev Med. 2011;52:104-8. https://doi.org/10.1016/j.ypmed.2010.11.019
https://doi.org/https://doi.org/10.1016/...
The use of television during meals also had a negative effect on sleep duration in a cross-sectional study with 4,072 children, aged between 4 to 13 years, in the Netherlands.2626. Jong E, Stocks T, Visscher TL, HiraSing RA, Seidell JC, Renders CM. Association between sleep duration and overweight: the importance of parenting. Int J Obes (Lond). 2012;36:1278-84. https://doi.org/10.1038/ijo.2012.119
https://doi.org/https://doi.org/10.1038/...
Also, the sedentary behavior resulting from the excessive use of electronic equipment favors weight gain, in addition to the negative effect on sleep quality.4747. Tucker JM, Howard K, Guseman EH, Yee KE, Saturley H, Eisenmann JC. Association between the family nutrition and physical activity screening tool and obesity severity in youth referred to weight management. Obes Res Clin Pract. 2017;11:268-75. https://doi.org/10.1016/j.orcp.2016.09.007
https://doi.org/https://doi.org/10.1016/...

Several studies report an association between overweight/obesity and the excessive use of electronic equipment as a reflection of sedentary lifestyle.2424. Corso AC, Caldeira GV, Fiates GM, Schmitz BA, Ricardo GD, Vasconcelos FA. Behavioral factors associated with overweight and with obesity in students in the State of Santa Catarina. Rev Bras Estud Popul. 2012;29:117-31. https://doi.org/10.1590/s0102-30982012000100008
https://doi.org/https://doi.org/10.1590/...
,1818. Bazán AM, Sellán MC, Vázquez AS, Díaz ML, Domínguez FS. Factors associated with overweight and childhood obesity in Spain according to the latest national health survey (2011). Esc Anna Nery Rev Enferm. 2018;22:e20170321. https://doi.org/10.1590/2177-9465-ean-2017-0321
https://doi.org/https://doi.org/10.1590/...
A study carried out in Spain with 3,752 individuals aged from 2 to 15 years old showed that children who spent more than two hours/day using electronic devices had higher rates of overweight when compared to those who spent less than two hours/day in these activities.1616. Carrillo-Larco RM, Bernabé-Ortiz A, Miranda JJ. Short sleep duration and childhood obesity: cross-sectional analysis in Peru and patterns in four developing countries. PLoS One. 2014;9:e112433. https://doi.org/10.1371/journal.pone.0112433
https://doi.org/https://doi.org/10.1371/...

One possible causal effect between the use of electronic devices and reducing sleep is the suppression of melatonin.4444. Sijtsma A, Koller M, Sauer PJ, Corpeleijn E. Television, sleep, outdoor play and BMI in young children: the GECKO Drenthe cohort. Eur J Pediatr. 2015;174:631-9. https://doi.org/10.1007/s00431-014-2443-y
https://doi.org/https://doi.org/10.1007/...
Several neurotransmitters and hormones control the wake-sleep cycle. Melatonin is a hormone primarily secreted by the pineal gland in the absence of light, and induces sleepness.3636. Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, et al. 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. Sleep. 2015;11:931-52. https://doi.org/10.5664/jcsm.4950
https://doi.org/https://doi.org/10.5664/...
The blue light emitted by electronic equipment, especially at night, may result in decreased melatonin release and consequent delay of sleep onset. This event may lead to circadian cycle deregulation, thus decreasing duration and quality of sleep.4444. Sijtsma A, Koller M, Sauer PJ, Corpeleijn E. Television, sleep, outdoor play and BMI in young children: the GECKO Drenthe cohort. Eur J Pediatr. 2015;174:631-9. https://doi.org/10.1007/s00431-014-2443-y
https://doi.org/https://doi.org/10.1007/...
,4848. Ajejas MJ, Sellán MC, Vázquez AS, Díaz ML, Domínguez FS. Factors associated with overweight and childhood obesity in Spain according to the latest national health survey (2011). Esc Anna Nery Rev. Enferm. 2018;22:e20170321. https://doi.org/10.1590/2177-9465-ean-2017-0321
https://doi.org/https://doi.org/10.1590/...
This becomes a vicious circle in the child’s routine, since excessive exposure to light emitted by these equipment affects sleep quality, and insufficient sleep predisposes to the use of such equipment.3232. Na M, Eagleton SG, Jomaa L, Lawton K, Savage JS. Food insecurity is associated with suboptimal sleep quality, but not sleep duration, among low-income head start children of pre-school age. Public Health Nutr. 2019;23:701-10. https://doi.org/10.1017/s136898001900332x
https://doi.org/https://doi.org/10.1017/...

Sleep debt might result in several deleterious consequences for health, such as stress, physical fatigue, difficulty concentrating, among others.1919. Agüero DS, Giraldo GS, Guerra JB. Relationship between nutritional status and sleep duration in Chilean school-age children. ALAN. 2017;67:1-5.,2525. Durán AS, Fuentes NC, Vásquez SQ, Cediel GG, Díaz VN. Relationship between nutritional status and sleep in school children from the San Miguel commune, Santiago, Chile. Rev Chil Nutr. 2012;39:30-7. https://doi.org/10.4067/s0717-75182012000100003
https://doi.org/https://doi.org/10.4067/...
Metabolic and behavior changes have also been related to sleep loss, which contributes to overweight and obesity.1616. Carrillo-Larco RM, Bernabé-Ortiz A, Miranda JJ. Short sleep duration and childhood obesity: cross-sectional analysis in Peru and patterns in four developing countries. PLoS One. 2014;9:e112433. https://doi.org/10.1371/journal.pone.0112433
https://doi.org/https://doi.org/10.1371/...
,1717. Agüero SD, Rivera PH. Association between the amount of sleep and obesity in Chilean schoolchildren. Arch Argent Pediatr. 2016;114:114-9. https://doi.org/10.5546/aap.2016.eng.114
https://doi.org/https://doi.org/10.5546/...
,2727. Christoph MJ, Grigsby-Toussaint DS, Baingana R, Ntambi JM. Physical activity, sleep, and BMI percentile in rural and urban Ugandan youth. Ann Glob Health. 2017;83:311-9. https://doi.org/10.1016/j.aogh.2017.04.005
https://doi.org/https://doi.org/10.1016/...
,1919. Agüero DS, Giraldo GS, Guerra JB. Relationship between nutritional status and sleep duration in Chilean school-age children. ALAN. 2017;67:1-5.,2525. Durán AS, Fuentes NC, Vásquez SQ, Cediel GG, Díaz VN. Relationship between nutritional status and sleep in school children from the San Miguel commune, Santiago, Chile. Rev Chil Nutr. 2012;39:30-7. https://doi.org/10.4067/s0717-75182012000100003
https://doi.org/https://doi.org/10.4067/...
Out of the 16 studies included in our literature search, 14 showed positive associations between short sleep duration and the development of overweight in the infant population. Three studies had a negative association between sleep and overweight/obesity.

Moreover, sleep loss may predispose to weight gain due to deregulation of metabolic profile during the night, such as insulin metabolism, increased cortisol secretion and decreased growth hormone (GH) concentration, which may favor lipogenesis.3131. Hitze B, Bosy-Westphal A, Bielfeldt F, Settler U, Plachta-Danielzik S, Pfeuffer M, et al. Determinants and impact of sleep duration in children and adolescents: data of the Kiel Obesity Prevention Study. Eur J Clin Nutr. 2009;63:739-46. https://doi.org/10.1038/ejcn.2008.41
https://doi.org/https://doi.org/10.1038/...
,4949. Landhuis CE, Poulton R, Welch D, Hancox RJ. Childhood sleep time and long-term risk for obesity: a 32-year prospective birth cohort study. Pediatrics. 2008;122:955-60. https://doi.org/10.1542/peds.2007-3521
https://doi.org/https://doi.org/10.1542/...

Among the mechanisms behind the relationship between sleep loss and overweight, food intake is influenced by sleep patterns and can trigger overweight/obesity.

The main hypothesis to explain this relationship is the fact that individuals with sleep restriction remain longer in wakefulness, which consequently increases energy demand, causing an increase in caloric intake in periods of sleep loss.1010. McDonald L, Wardle J, Llewellyn CH, Fisher A. Nighttime sleep duration and hedonic eating in childhood. Int J Obes (Lond). 2015;39:1463-6. https://doi.org/10.1038/ijo.2015.132
https://doi.org/https://doi.org/10.1038/...
Also, a greater propensity to hedonic eating among individuals with short sleep duration can lead to higher caloric intake in this population. In a cross-sectional study from the New Zealand twin cohort, it was observed that children who slept less at five years of age were more likely to have food responsiveness, i.e., these children had a higher preference for highly palatable and consequently more caloric foods, characterizing hedonic and non-physiological hunger.5050. Spruyt K, Molfese DL, Gozal D. Sleep duration, sleep regularity, body weight, and metabolic homeostasis in school-aged children. Pediatric. 2011;127:345-52. https://doi.org/10.1542/peds.2010-0497
https://doi.org/https://doi.org/10.1542/...
,5151. Burt J, Dube L, Thibault L, Gruber R. Sleep and eating in childhood: a potential behavioral mechanism underlying the relationship between poor sleep and obesity. Sleep Med. 2014;15:71-5. https://doi.org/10.1016/j.sleep.2013.07.015
https://doi.org/https://doi.org/10.1016/...

In association with this, studies report a higher prevalence of the consumption of food high in energy density and poor in nutrients in children who sleep later. These children showed a preference for fast-food, pastries, sweetened beverages, soft drinks, and a lower consumption of fruits and vegetables.77. King C. Soft drinks consumption and child behaviour problems: the role of food insecurity and sleep patterns. Public Health Nutr. 2017;20:266-73. https://doi.org/10.1017/s1368980016002093
https://doi.org/https://doi.org/10.1017/...
,3030. Golley RK, Maher CA, Matricciani L, Olds TS. Sleep duration or bedtime? Exploring the association between sleep timing behaviour, diet and BMI in children and adolescents. Int J Obes (Lond). 2013;37:546-51. https://doi.org/10.1038/ijo.2012.212
https://doi.org/https://doi.org/10.1038/...
,3131. Hitze B, Bosy-Westphal A, Bielfeldt F, Settler U, Plachta-Danielzik S, Pfeuffer M, et al. Determinants and impact of sleep duration in children and adolescents: data of the Kiel Obesity Prevention Study. Eur J Clin Nutr. 2009;63:739-46. https://doi.org/10.1038/ejcn.2008.41
https://doi.org/https://doi.org/10.1038/...
Likewise, the high consumption of stimulant foods, such as chocolate and soft drinks, may be associated with the development of sleep disorders, such as parasomnias.3333. Ruotolo F, Prado LB, Ferreira VR, Prado GF, Carvalho LB. Intake of stimulant foods is associated with development of parasomnias in children. Arq Neuropsiquiatr. 2016;74:62-6. https://doi.org/10.1590/0004-282x20150193
https://doi.org/https://doi.org/10.1590/...

These changes in dietary patterns, with the increase in low nutritional quality food consumption, lead to micronutrient deficiency, such as anemia, due to the low consumption of iron-rich foods. It’s important to highlight the relationship of anemia with reductions in sleep duration and physical activity level.3434. Kordas K, Casavantes KM, Mendoza C, Lopez P, Ronquillo D, Rosado JL, et al. The association between lead and micronutrient status, and children’s sleep, classroom behavior, and activity. Arch Environ Occup Health. 2007;62:105-12. https://doi.org/10.3200/aeoh.62.2.105-112
https://doi.org/https://doi.org/10.3200/...
,3535. Kordas K, Siegel EH, Olney DK, Katz J, Tielsch JM, Chwaya HM, et al. Maternal reports of sleep in 6-18-month-old infants from Nepal and Zanzibar: association with iron deficiency anemia and stunting. Early Hum Dev. 2008;84:389-98. https://doi.org/10.1016/j.earlhumdev.2007.10.007
https://doi.org/https://doi.org/10.1016/...

Studies conducted in adults suggest that, in sleep loss conditions, there is a change in the appetite-regulating hormones, causing a decrease in leptin and an increase in ghrelin concentrations, causing a greater sense of hunger.88. Spiegel K, Tasali E, Penev P, Van Cauter E. Brief communication: sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Ann Intern Med. 2004;141:846-50. https://doi.org/10.7326/0003-4819-141-11-200412070-00008
https://doi.org/https://doi.org/10.7326/...
However, a study conducted with 414 individuals, aged between 6 and 19 years old, observed an increase in leptin concentrations in girls with sleep restriction, which suggests that chronic sleep loss may lead to future changes in metabolism.3131. Hitze B, Bosy-Westphal A, Bielfeldt F, Settler U, Plachta-Danielzik S, Pfeuffer M, et al. Determinants and impact of sleep duration in children and adolescents: data of the Kiel Obesity Prevention Study. Eur J Clin Nutr. 2009;63:739-46. https://doi.org/10.1038/ejcn.2008.41
https://doi.org/https://doi.org/10.1038/...

However, it’s important to emphasize that there is still a limited number of studies that try to explain mechanisms related to sleep loss, metabolic consequences and weight gain. Also, a frequent problem is the lack of studies with objective measurements of sleep, as most studies do not use validated questionnaires to address sleep duration and quality. Moreover, studies with careful evaluation and analysis of food intake and behavior, in addition to a valid measurement of sleep in this population, are needed. It is important to emphasize that the present literature review was conducted with a specific population (children), and the conclusions might be different across other population strata. Also, the proposed mechanisms to explain sleep and nutritional status relationship come from studies in adults or experimental studies. This reinforces the importance of studying these mechanisms in infant population.

It is possible to conclude, based on the reviewed literature, that sleep duration is related to the development of overweight and obesity in the infant population. The amount of sleep also contributes to changes in eating behavior, being one of the contributing mechanisms to weight gain. Therefore, health professionals must recognize the association between lifestyle parameters, such as sleep, eating behavior, and physical activity level, and be able to include sleep recommendations in nutritional counseling.

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Funding

  • This study did not receive any funding.

Publication Dates

  • Publication in this collection
    09 Sept 2022
  • Date of issue
    2022

History

  • Received
    01 Dec 2020
  • Accepted
    13 Apr 2021
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E-mail: rpp@spsp.org.br