Association of sleep duration and snack consumption in children and adolescents: The CASPIAN-V study

Sleep status and its association with dietary habits among children and adolescents in Shandong Province, China: a cross-sectional study

BACKGROUND

Insufficient sleep is a widespread issue among children and adolescents, influenced by various factors, including dietary habits. This study aimed to examine the relationship between dietary habits and sleep insufficiency in children and adolescents aged 6 to 18 in Shandong Province, China.

METHODS

Data were derived from a 2024 survey assessing sleep status among children and adolescents in Shandong Province. the prevalence of insufficient sleep was determined, and univariable Χ² test was used to explore associations between daily life behaviors and sleep duration. Multivariable logistic regression was employed to analyze the effect of specific dietary habits on sleep insufficiency, adjusting for potential confounding factors.

RESULTS

The overall prevalence of insufficient sleep was 53.28%. After adjusting for confounders, the logistic regression model indicated that regular breakfast consumption 4 ~ 6 times per week (OR = 0.578, 95% CI 0.522 ~ 0.640) or every day (OR = 0.502, 95% CI: 0.450 ~ 0.561) was associated with significantly lower odds of insufficient sleep. Higher vegetable intake more than five times per week (OR = 0.376, 95% CI: 0.338 ~ 0.418) and fruit consumption 4 ~ 5 times per week (OR = 0.866, 95% CI: 0.816 ~ 0.918) or more than five times per week (OR = 0.446, 95% CI: 0.405 ~ 0.490) were also linked to reduced odds of insufficient sleep. Conversely, higher sugary beverage consumption 4 ~ 5 times per week (OR = 2.066, 95% CI: 1.903 ~ 2.243) or more than five times per week (OR = 2.021, 95% CI: 1.838 ~ 2.223) significantly increased the likelihood of insufficient sleep. Fast food consumption 2 ~ 3 times per week (OR = 1.025, 95% CI: 1.003 ~ 1.048) or more than three times per week (OR = 1.036, 95% CI: 1.002 ~ 1.071) was also associated with higher odds of insufficient sleep (P < 0.05).

CONCLUSION

Dietary habits significantly influence sleep duration among children and adolescents in Shandong Province. Regular breakfast consumption, increased intake of vegetable and fruit, and reduced consumption of sugary beverage and fast food were associated with improved sleep duration. These findings underscored the importance of promoting healthy eating behaviors as a key strategy for addressing sleep-related issues and improving overall well-being in young populations.

Influence of Sleep Time on the Consumption of Ultra-Processed Foods in Adolescents in a Capital of Brazil: A Longitudinal Study

BACKGROUND/OBJECTIVES

The study prospectively assessed the association between sleep duration and the consumption of ultra-processed foods in adolescent students from a Brazilian capital.

METHODS

We observed 1431 adolescents participating in the Longitudinal Study on sedentary behavior, physical activity, dietary habits, and adolescent health, aged 10 to 14 years, in the years 2014 to 2017. The percentage of consumption of ultra-processed foods was evaluated by the Friedman test. Generalized Estimation Equation (GEE) models with parameters for robust analysis were used to verify the prospective association between sleep and the consumption of ultra-processed foods.

RESULTS

The percentage consumption of ultra-processed foods in relation to total daily calories increased in boys between 15 and 17 years old (31.8% in 2015 to 35.8% in 2017), being more stable among older girls (36.7% in 2015 to 37.7% in 2017), which may have occurred due to the influence of the social environment, reduced critical capacity, and lower concern for nutrition. This excessive consumption can lead to health and body composition impairments. Over time, adolescents who were in the fourth quartile of sleep had a 1.4% reduction (95% CI -2.49; -0.28) in the energy percentage from ultra-processed foods. When adjusting the initially used model in the GEE (Generalized Estimation Equation) with sociodemographic variables (income, maternal education, age) and lifestyle factors, sleep duration decreased by 2.1% (95% CI -4.09; -0.22) only in boys. The shorter duration of sleep in adolescents has been shown to be associated with unhealthy behavioral factors, such as a preference for fatty and sugary foods. There were no statistically significant associations for girls in this model.

CONCLUSIONS

Sleep influences the consumption of ultra-processed foods in adolescents, showing that as sleep time increases, the consumption of foods classified as ultra-processed decreases.

Sleep timing behaviour, sleep duration and adherence to obesogenic dietary patterns from pre-school to school age: results from the Portuguese birth cohort Generation XXI

In an obesogenic environment, short sleeping may increase opportunistic eating. The timing of sleep might also influence the drive to eat. This study investigated the prospective association of sleep timing and duration with diet in 5286 children from the Portuguese birth cohort Generation XXI, evaluated at 4 and 7 years of age. At 4 years, sleep duration was categorised into ≤10 and >10 h. Four sleep timing categories were generated based on the median split for sleep-onset and -offset times: 'Early Sleep-Early Wake'; 'Early Sleep-Late Wake'; 'Late Sleep-Early Wake'; 'Late Sleep-Late Wake'. At 7 years, diet was obtained by a food frequency questionnaire and three dietary patterns were included: 'Healthier', 'Energy-Dense Foods (EDF)' and 'Snacking'. The Healthy Eating Index was used to evaluate diet quality. Multinomial logistic regression models and generalised linear models were performed. Children who had a late sleep, independently of the time of waking up, had higher odds of following the 'EDF' pattern, compared with the 'Healthier'. Boys who had late sleep and/or late wake had also higher odds of following the 'Snacking' pattern and had poorer diet quality. In both sexes, a late sleep or late wake were associated with a lower diet quality, compared to the group 'Early Sleep-Early Wake', and independently of nap behaviour. In boys, shorter sleep duration was associated with a poorer diet. In conclusion, pre-schoolers with late bedtimes or wake-up times have worse dietary patterns and poorer diet quality at the age of 7 years, which seems to be independent of sleep duration.

The Relationship Between Fast Food Consumption and Daily Lifestyle Changes During School Closures Following the COVID-19 Pandemic: A Cross-Sectional Study Among Adolescents in Korea

OBJECTIVE

Increased fast food consumption can have adverse effects on health and well-being among adolescents, posing a significant public health concern. The school closures due to the coronavirus disease-2019 (COVID-19) pandemic have led to changes in eating patterns and disrupted a balance diet among adolescents. This study explored the factors associated with fast food consumption among adolescents during school closures due to the COVID-19 pandemic.

METHODS

A total of 1,710 middle and high school students in Gwangju, South Korea participated in a cross-sectional survey. The self-administered questionnaire included items assessing dietary intake, physical activity, sleep, media use, and sociodemographic information. The Patient Health Questonnaire-9, Generalized Anxiety Disorder-7, and three item version of the UCLA Loneliness Scale were also administered. Multivariable logistic regression was used to examine the factors associated with increased fast food consumption.

RESULTS

Approximately 34.6% of the surveyed adolescents reported increased fast food consumption during school closures, as well as increased sleep duration, increased sedentary behaviors including watching TV and using the internet, and reduced physical activity. Multivariable logistic regression analysis revealed that fast food consumption during school closures was associated with irregular patterns of main meals and sleep, decreased physical activity, increased internet use, and a lack of daytime adult supervision.

CONCLUSION

Our results highlight the need for dietary and lifestyle monitoring and guidelines to promote health among adolescents, especially during school closures. In conclusion, nutrition intervention programs aiming to limit fast food consumption and enhance healthy dietary habits among adolescents during long-term school closures are warranted.

The path between breakfast eating habit, sleep duration and physical activity on obesity status: An epidemiological study in schoolchildren

Background: Although the literature suggests that skipping breakfast, insufficient sleep, and reduced physical activity are associated with childhood obesity their co-influence and their in-between interactions on weight status have rarely been studied. Aim: To examine the co-influence of breakfast eating habits, sleep duration, and physical activity on the weight status of children 10-12 years old from several schools of Greece. Methods: A cross-sectional study was conducted on 1688 students in Greece, during 2014-2016. Children's Body Mass Index (BMI) was calculated and classified according to the International Obesity Task Force (IOTF) classification. Logistic regression models and path analysis were used. Results: Overweight/obesity prevalence was higher in boys (32.5% vs. 20.4%; p < 0.001). Average sleep duration decreased the odds of overweight/obesity [OR (95% CI): 0.86 (0.76, 0.97)] independently of the frequency of breakfast habit. Interaction between sleep duration with breakfast habit (p = 0.002) and physical activity (p < 0.001) was observed. Path analysis showed a negative association of BMI with sleep duration (standardized beta = -0.095, p < 0.001). A third-order interaction between breakfast habit, sleep duration, and physical activity revealed that daily breakfast eating along with adequate sleep and moderate/adequate physical activity levels, decreased the odds of over-weight/obesity by 55% [OR 0.45, 95% CI (0.27, 0.72)]. Conclusion: Although sleep duration is inversely associated with weight status independently of breakfast habit, the co-influence of adequate sleep duration with frequent breakfast eating and moderate/adequate physical activity seems to be a profoundly higher associated as a result of synergy against childhood obesity.

Associations between Milk Intake and Sleep Disorders in Chinese Adults: A Cross-Sectional Study

We aimed to examine the association of milk intake with sleep disorders and their specific indicators. The current study included 768 adults aged 28-95 from Wenling, China. Milk intake was assessed using a food frequency questionnaire with ten food items, while sleep disorders were measured using the Pittsburgh Sleep Quality Index (PSQI), with higher scores indicating poorer sleep. The participants were divided into two groups according to the average intake of milk per week: rare intake (≤62.5 mL/week) and regular intake (>62.5 mL/week). Primary measurements were multivariate-adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for the prevalence of sleep disorders concerning regular milk intake compared with rare intake. In secondary analyses, linear regression analyses were performed to assess the effects of milk intake on sleep disorders and their specific dimensions. Regular intake of milk did not have a significant association with sleep disorders compared with rare intake (adjusted OR: 0.72, 95%; CI: 0.51, 1.03), but this association was found to be pronounced with sleep disturbances (OR: 0.49, 95%; CI: 0.28, 0.87). Increased intake of milk was significantly associated with the lower scores of PSQI for sleep quality (β: -0.045, 95%; CI: -0.083, -0.007) and sleep disturbances (β: -0.059, 95%; CI: -0.090, -0.029), respectively. When stratified by age and gender, the benefits of milk intake for sleep disorders and sleep disturbances were more significant in older adults (≥65) and men than in younger persons and women. In summary, regular milk intake benefits sleep quality, which may contribute to nutritional psychiatric support for prevention against sleep disorders.

Three-Year School-Based Multicomponent Intervention May Change Fruit and Vegetable Preferences in Primary School Children-A Quasi-Randomized Trial

Preference could be the trigger for fruit and vegetable (FV) consumption in children and could be modified by appropriate intervention to increase the acceptance of FVs. The primary objective of this study was to investigate the effects of the three-year school-based multicomponent intervention "Nutri-školica" on the FV preferences of primary school children. It also aimed to explore whether a positive change in FV preferences could lead to an increase in actual FV consumption. The study was conducted in 14 primary schools from the city of Zagreb on 193 children (52.3% boys; age, 7.7 ± 0.4 years; n = 85 in the control group and n = 108 in the intervention group) who completed a preference questionnaire before and after the intervention with a 5-point hedonic smiley-face scale, where 5 means "I like it a lot." The per-protocol approach was used for data analysis (28.3% of children from the study sample). After the intervention, children in the intervention group (before: 3.1 ± 0.8; after: 3.5 ± 0.8) increased their FV preferences significantly more than children in the control group (before: 3.2 ± 0.8; after: 3.3 ± 0.7). Children's FV preferences changed most toward the varieties for which they had the least preferences at the beginning of the study. Participation in the intervention had a stronger effect on changing FV intake than change in FV preferences among primary school children. In summary, the present study highlighted that a targeted intervention can increase children's FV preferences, but that participation in the intervention is substantial for increasing FV intake.

Association of social jetlag and eating patterns with sleep quality and daytime sleepiness in Japanese high school students

A high prevalence of excessive daytime sleepiness and poor sleep quality has been reported in adolescents, but the effects of social jetlag on sleep quality and daytime sleepiness are unclear. Therefore, we assessed the association of sleep and eating patterns with daytime sleepiness and sleep quality among a total of 756 Japanese high school students. Participants completed the Pittsburgh Sleep Quality Index to evaluate sleep quality, the Pediatric Daytime Sleepiness Scale to evaluate daytime sleepiness, and an 8-day sleep diary. Data on average sleep duration, social jetlag, midsleep on free days sleep corrected, and the differences in the first and last meal timing between school days and non-school days were obtained from participants' sleep diaries. The results reveal that social jetlag is associated with differences in the first meal timing between school days and non-school days, and that social jetlag of more than 2 hr is associated with extremely poor sleep quality and excessive daytime sleepiness in Japanese high school students. Our findings suggest that reducing social jetlag to within a 2-hr window is important to prevent poor sleep quality and excessive daytime sleepiness for this population.

Association between short sleep duration and intake of sugar and sugar-sweetened beverages: A systematic review and meta-analysis of observational studies

BACKGROUND

Findings of previous investigations that evaluated the relationship between sleep duration and sugar or sugar-sweetened beverages (SSBs) intake have been inconsistent. We aimed to summarize extant research that assessed the relation between short sleep duration and sugar and SSB intake.

METHODS

A comprehensive search of PubMed, ISI Web of Sciences, Scopus, Science Direct, Embase, and Google Scholar was conducted. All observational studies that reported sleep duration as the exposure and intake of sugar or sugary drinks as the outcome were included. The quality of included studies was evaluated using the Newcastle-Ottawa Scale. The body of evidence was assessed using the GRADE approach. Random and fixed effects models were used to estimate pooled OR and 95% confidence intervals.

RESULTS

Twenty-two studies in children and twelve in adults were included in the systematic review. Only 10 studies in children and 3 investigations in adults provided odds ratios (95% confidence intervals) for this association and could be included in the meta-analysis. All studies had a cross-sectional design and found a negative association between sleep duration and sugar in children, but not in adults. SSB intake was lower in those with sufficient sleep in all populations. Compared with those with sufficient sleep, children with short sleep duration had 16% (significant) higher odds of consuming sugar (OR: 1.16; 95% CI: 1.10, 1.21), 21% higher odds of soda intake (OR: 1.21; 95% CI: 1.16, 1.26), and 92% higher odds of consuming energy drink intake (OR: 1.92; 95% CI: 1.66, 2.22). However, sleep duration was not significantly associated with soft drink intake in children (OR: 1.17; 95% CI: 0.93, 1.48). In adults, the odds of drinking soda in those with short sleep duration was 1.2 times more than in those with sufficient sleep (OR: 1.20; 95% CI: 1.12, 1.28). Also, low vs. optimal sleep duration in adults was associated with a 58% increased intake of energy drinks (OR: 1.58; 95% CI: 1.31, 1.90). Of note, these findings in the adult population resulted from only 2 included investigations, due to the limited number of studies.

CONCLUSION

The evidence reviewed supports a significant association between shorter sleep duration and higher SSBs intake in both children and adults, while such association with higher total sugar intake was significant in children but not in adults. Further research with more accurate measurements, sex-specific, and prospective designs should be carried out to clarify the causality and underlying mechanisms.

Sleep duration and eating behaviours among adolescents: a scoping review

INTRODUCTION

In the past decade, investigations of the relationship between sleep duration and eating behaviours have been emerging; however, a formal synthesis of the literature focussed on adolescent populations has not yet been conducted. We conducted a scoping review of the literature examining the relationship between sleep duration and eating behaviours in adolescents. Gaps in the research and directions for future research were identified based on the findings.

METHODS

A systematic search was employed on four research databases: PubMed, PsycInfo, CINAHL and Scopus; relevant grey literature was also reviewed. Studies that reported on the relationship between sleep duration and eating behaviours among high school-aged adolescents were included in the review. Data were extracted, charted and synthesized into a narrative. Consistent with the purpose of a scoping review, the methodological quality of the studies was not appraised. Stakeholders were consulted to validate the findings and provide insight into the interpretation and identification of pressing gaps in the research that remain to be addressed.

RESULTS

In total, 61 studies published between 2006 and 2021 met the criteria for review. Existing research focussed heavily on examining sleep duration in relation to intake of food from certain food groups, beverages and processed foods, and relied on a population study design, cross-sectional analyses and self-report measures.

CONCLUSION

Future research is needed to understand the link between sleep duration and eating-related cognition, eating contexts and disordered eating behaviours in order to better understand how ensuring sufficient sleep among adolescents can be leveraged to support healthier eating practices and reduce diet-related risks.

The Association between Diet and Sleep Quality among Spanish University Students

While it has long been recognized that diet is a leading behavioral risk factor for human health, recent scientific findings have also suggested that diet and sleep quality may be connected. The purpose of the present study is to evaluate the association between diet and sleep quality among a group of Spanish university students. To do so, a cross-sectional study of 868 students was carried out. Sleep quality was assessed using the Spanish version of the Pittsburgh Sleep Quality Index (PSQI), while diet was assessed using the Spanish Healthy Eating Index (SHEI). The study revealed a noteworthy rate of bad sleepers (51.6%) and students whose diet needed modifications (82.2%). Unhealthy eaters were more likely to have poor sleep quality (aOR = 4.20; CI 95%: 2.07-8.52). The unbalanced intake of vegetables (aOR = 1.63; CI 95%: 1.14-2.34), fruits (aOR = 4.08; CI 95%: 2.90-5.74), dairy products (aOR = 1.96; CI 95%: 1.41-2.72), lean meats (aOR = 1.82; CI 95%: 1.19-2.78), legumes (aOR = 1.43; CI 95%: 1.00-2.02), sweets (aOR = 1.60; CI 95%: 1.13-2.25) and sugary soft drinks (aOR = 1.46; CI 95%: 1.07-1.99) was associated with lower sleep quality.

A greater modified Mediterranean diet score is associated with lower insomnia score among adolescent girls: a cross-sectional study

Background

Previous studies has shown that a low quality diet is related to sleep disorders. A Mediterranean diet is considered to be a high quality diet and has been shown to have beneficial effects on overall health. Thus, the aim of our study was to investigate the association between adherence to Mediterranean dietary pattern and insomnia score among adolescent girls.

Methods

The data for 733 adolescent girls between 12–18 years old was assessed in this cross-sectional study. A 147 item-food frequency questionnaire was used to assess dietary intake. A modified model of Mediterranean diet score was calculated that ranged from 0–9 points. A validated version of Insomnia Severity Index questionnaire was used to assess insomnia. To explore the association between modified Mediterranean (mMED) diet score and insomnia, linear regression was conducted in crude and adjusted models (energy intake adjustmet in Model I, further adjustments were performed for physical activity, father’s and mother’s education in Model II and full adjusted model adjusted for age, body mass index percentiles, and abdominal obesity).

Results

A significant inverse association between mMED diet score and insomnia score was observed using a crude model (β = -0.091, 95% confidence interval (CI): -0.392 to -0.046); P-value = 0.013) and also after adjustment for confounding factors in Model I (β = -0.098, CI: -0.423 to -0.045; P = 0.015), Model II (β = -0.092, CI: -0.410 to -0.029; P-value = 0.024), Model III (β = -0.082, CI: -0.385 to -0.006); P = 0.044).

Conclusion

There was an inverse relationship between adherence to the mMED diet score and insomnia level among Iranian adolescent girls. Prospective studies are needed to confirm these results and clarify whether a causal relationship exists.

The Association of Sleep Duration with Breakfast Patterns and Snack Behaviors among Chinese Children Aged 6 to 17 Years: Chinese National Nutrition and Health Surveillance 2010–2012

A significant increase in the prevalence of short sleep among children has been observed. Short sleep may be associated with unhealthy breakfast and snacking behaviors. The purpose of the current study was to explore the associations of short sleep with breakfast and snacking behaviors among children. Data were obtained from the 2010–2012 China National Nutrition and Health Surveillance (CNNHS). A total of 5254 children aged 6 to 17 years were included. Sleep duration was classified into three categories: moderate sleep, slightly short sleep, and severely short sleep. Breakfast behaviors included skipping breakfast, food diversity, intake of energy and macronutrients, and their proportion of daily total intake. Snack behaviors included snack consumption rate/frequency, types, intake of energy and macronutrients, and proportion of daily total intake. Multiple linear regression and multivariate logistic regression were used for analysis, with models adjusted for the potential effects of gender, age, region, and family income level. The bootstrapping method was used to calculate the 95% confidence intervals of the model statistics. Results showed that slightly short sleep (OR = 1.15, 95%CI: 1.00, 1.33)) and severely short sleep (OR = 1.36, 95%CI: 1.04, 1.77) was related to higher rates of skipping breakfast compared to moderate sleep. Severely short sleep was associated with higher energy (β = 28.44, 95%CI: 31.97, 44.70), carbohydrate (β = 6.62, 95%CI: 8.29, 8.84) and protein (β = 1.17, 95%CI: 1.44, 1.70) intake at breakfast and breakfast accounted for a higher proportion of total daily energy (β = 1.39, 95%CI: 1.48, 2.52), protein (β = 2.26, 95%CI: 3.16, 5.84) and carbohydrate (β = 0.83, 95%CI: 0.07, 3.41). Severely short sleep was associated with higher energy (β = 27.4, 95%CI: 18.64, 69.41), protein (β = 0.8, 95%CI: 0.48, 2.40), and fat (β = 1.40, 95%CI: 1.21, 3.16) intake at snacks and snacks accounted for a higher proportion of total daily protein intake (β = 1.23, 95%CI: 0.71, 3.58) and fat intake (β = 2.74, 95%CI: 3.13, 6.09). Slightly short sleep was associated with higher energy (β = 7.28, 95%CI: 0.15, 28.13) and carbohydrate (β = 1.67, 95%CI: 0.86, 5.73) intake at snacks and snacks accounted for a higher proportion of total daily carbohydrate intake. Children with severely short sleep were more likely to choose sugar-sweetened beverages (SSBs) as snacks (16.5%) and intake them more frequently, at a daily consumption of 204.7 g and 26.7 g per night. Overall, short sleep was associated with unhealthy breakfast patterns and snack behaviors among children. Children with short sleep had higher intake of energy and macronutrients at breakfast and snacks compared with those with moderate sleep. Promoting adequate sleep among children may have a positive effect on developing healthy eating behaviors.

The Association Between Frequent Sugar-Sweetened Beverage Intake and Sleep Duration in School Children: A Cross-Sectional Study

Background

Higher consumption of sugar-sweetened beverages (SSBs) maybe association with children's sleep pattern. However, few studies have considered this association in Asia, especially in school children. This study investigated the relationship between children's consumption frequency of such beverages and their sleep duration.

Methods

Participants aged 6–12 years were analyzed from two survey data in 2012 and 2013–2016 Nutrition and Health Surveys in Taiwan. A total of 2,628 participants were included in the analysis (2012, N = 1,267; 2013–2016, N = 1,361). Beverages weekly consumption were divided into low and high intake groups by medians cut-off points. The sleep variables were the sleep duration at night (including school days and weekends) and sleep debt. After controlling the confounders, the correlation between sugar-sweetened beverage consumption and sleep duration was examined using multinomial logistic regression analysis.

Results

The students slept for an average of 8.8 h on school days and 9.7 h on weekends. Relative to the low SSB intake group, the high intake group exhibited shorter sleep durations on school days (P < 0.001), greater sleep debt (P = 0.049). In logistic regression, high intake group were more likely to sleep for <8.5 h on school days (OR = 1.67, P = 0.002) and exhibit >2 h of sleep debt than low intake group (OR = 1.41, P = 0.022).

Conclusions

Children who had consumed sugar-sweetened beverages frequently slept for shorter durations at night on school days and exhibited greater sleep debt. The causal relationship was not clear. Nonetheless, these two factors are important in promoting children health.

Factors Related to Diet Quality: A Cross-Sectional Study of 1055 University Students

Given that there is only a limited body of evidence available concerning the dietary habits of Spanish university students, the present study assesses the quality of this group's diet, their adherence to the National Food-Based Dietary Guidelines, and the predictive factors of their diet quality. To do so, a cross-sectional study was performed on a sample of 1055 students. The quality of the participants' diets was then analysed by using the Spanish Healthy Eating Index, and then their level of compliance was assessed in light of the dietary recommendations put forth by the Spanish Society for Community Nutrition. According to these standards, only 17.4% of the participants had a healthy diet. The level of compliance with the recommendations was poor, highlighting especially the low levels of "fruit" and "vegetables" that they consumed as well as high levels of "cold meats and cuts" and "sweets". The factors that predicted a worse diet are being male, living alone, low levels of physical activity, smoking, high alcohol intake, leading a sedentary lifestyle, psychological distress, and insomnia (p < 0.005). Furthermore, participants with low or high body weights showed signs of a higher quality diet (p < 0.001). The present findings suggest that a significant proportion of university students ought to change their dietary habits; these also attest to the importance of developing strategies that are directly targeted at university students in order to promote a healthy diet.

School schedule affects sleep, but not physical activity, screen time and diet behaviors

BACKGROUND

Behavioral changes during adolescence are affected by biological and social aspects. However, environment aspects, which are beyond adolescents' control, also contribute to behavior adoption, and school may have a significant impact in these behaviors. This cross-sectional study aims to investigate how lifestyle behaviors are associated with the school shift attended by high school students.

METHODS

The sample comprised 635 high school students (51.2% girls, 16.33 ± 1.0 years old) from Southern Brazil. Physical activities of different intensities (light and moderate-to-vigorous), sedentary behaviors, and sleep (duration, efficiency, and timing) were measured using accelerometers. Engagement in sport and non-sport activities, screen time indicators, and diet were self-reported. Linear models were fitted to compare each lifestyle behavior between the two school shifts.

RESULTS

Students attending the afternoon shift slept (β = 01:29 95%CI 01:13; 01:46) and woke up later (β = 01.41 95%CI 01:27; 01:54), and had a longer sleep duration (β = 00:12 95%CI 0:02; 00:21) than those attending the morning shift. However, the sleep efficiency of those in the afternoon shift was lower than their peers in the morning shift (β = -1.89 95%CI -3.01; -0.77).

CONCLUSIONS

School schedule was associated with sleep behaviors of adolescents, but not with other lifestyle behaviors.

Longitudinal Associations Among Diet Quality, Physical Activity and Sleep Onset Consistency With Body Mass Index z-Score Among Toddlers in Low-income Families

BACKGROUND

Habits surrounding health behaviors (i.e., sleep, physical activity, diet) are developed in toddlerhood. Lack of consistent health habits may increase obesity risk among toddlers in low-income families.

PURPOSE

To compare the role of sleep onset consistency, physical activity and diet quality as mediators between household poverty and toddler weight.

METHODS

Two hundred and seven toddlers (mean age = 20.2 months, 46% female, 68.1% Black) participating in an obesity prevention trial were assessed at three time points over 12 months. Using Actical accelerometers, we assessed sleep and physical activity at each time point for up to 1 week. We defined sleep onset consistency as the standard deviation of sleep onset across all days. We calculated the Healthy Eating Index-2015 from a 24-hr dietary recall. We used WHO standards to calculate BMI-for-age z-scores from toddlers' weight/length, and calculated poverty ratio from parent-reported income and family size. Multilevel mediation models tested toddler sleep onset consistency, physical activity, and diet quality as mediators between household poverty and toddler BMI z-score.

RESULTS

Toddlers from households with higher poverty ratios had more inconsistent sleep onset times. Toddlers with more inconsistent sleep onset times had higher BMI z-scores across all timepoints, even when accounting for physical activity and diet quality. Sleep onset consistency indirectly explained the association between household poverty and BMI z-score.

CONCLUSIONS

Inconsistent sleep schedules could help explain the association between poverty and BMI. Future research should examine strategies to support low-income families to develop and maintain routines as a mechanism to prevent obesity and reduce disparities.

TRIAL REGISTRATION NUMBER

NCT02615158.