Chronotype, social jetlag and sleep debt are associated with dietary intake among Brazilian undergraduate students

Exploring the associations between chronotype, meal frequency, and physical activity: A population-based study in adults

Chronotype is an established concept designed to capture the internal clock's phase in real-life conditions. It is vital in many aspects of daily life and can interfere considerably with numerous factors in a given population. Recognizing nonmodifiable and modifiable factors is crucial for identifying covariates of interest when studying the link between chronotype and health status. To date, chronotype and its related factors have not been extensively investigated. The present study aimed to explore the association of chronotypes with meal frequency, physical activity, and demographic factors among the Saudi population. This cross-sectional web-based questionnaire involved 1369 adults (aged 18 years and above) from the general public in Saudi Arabia and was conducted between March and May 2019. Chronotype was assessed using the reduced version of the original Horne and Ostberg morningness-eveningness questionnaire (MEQ). Meal frequencies and demographics data (age, gender, marital status, place of residence, educational level, employment status, income) were obtained. Physical activity level was also obtained using the international physical activity questionnaire. The MEQ scores group individuals into three categories: morning-type, neither-type, and evening-type. The neither-type individuals represented 41.6% (95% confidence interval [CI], 37.5% - 45.6%) of the study population, followed by the morning-type (34.1%; 95% [CI], 29.8% - 38.4%), then the evening-type (24.3%, 95% [CI], 19.6% - 28.9%). Chronotype was significantly associated with age, marital status, employment status and monthly income (All p < 0.05). Significant associations between chronotype with meal frequencies (number of meals per day, breakfast frequency, lunch frequency, and dinner frequency) and physical activity were also observed (All p < 0.05). This study highlights that meal frequencies and physical activity levels are associated with chronotype distribution. Furthermore, demographics, including age, marital status, employment status, and income, were associated with chronotype distribution.

Relationship between social jetlag and body mass index in nurses working shift schedules: a cross-sectional study

This study aimed to explore the relationship between shift-working nurses' social jetlag and body mass index (BMI) and provide a theoretical basis for nursing managers to develop appropriate health interventions. Shift work is unavoidable in nursing and is associated with circadian rhythm disorders. Social jetlag is prevalent in shift-working nurses and is associated with adverse health outcomes (particularly metabolism-related indicators). BMI is a significant metabolic indicator, and research has demonstrated its effectiveness in predicting the formation of metabolic syndrome. The relationship between social jetlag and BMI can be explained by considering physiological, psychological, and behavioral factors. However, most studies on social jetlag and health status are focused on non-shift nurse populations, with fewer studies on shift workers. Five tertiary hospitals located at similar latitudes in Southwest China were selected for the study. We surveyed 429 shift-working nurses using sociodemographic data, the Munich Chronotype Questionnaire for Shift Workers, and BMI. The restricted cubic spline model was used to analyze the relationship between social jetlag and BMI among shift-working nurses, and segmented linear regression was performed around the inflection point using multiple linear regression analysis. The results revealed that social jetlag (82.0 [85.0] min) was experienced by 64.6% of the shift-working nurses. After controlling for confounding variables, the model with seven knots had the lowest accepted Akaike information criterion value, and there was a U-shaped relationship between shift-working nurses' BMI and social jetlag in this model; its inflection (lowest) point of 20.7 was considered the cut-off point. Segmented regression showed that for BMI < 20.7, BMI was significantly negative with standardized social jetlag; whereas with BMI > 20.7, BMI was significantly positive with standardized social jetlag. BMI has a U-shaped relationship with social jetlag, and attention should be paid to overweight or underweight shift-working nurses to detect early circadian rhythm disorder. Shift-working nurses with high social jetlag tended to have higher/lower BMI, which should be further investigated in the future, to minimize metabolic diseases among them.

Associations between chronotype, diet quality and timing of energy intake in Portuguese children and adolescents: The potential role of summer holidays

Later chronotypes may be associated with lower diet quality and later timing of energy intake in paediatric age. Period of data collection of these variables may affect these parameters and inter-relationship. We aimed to assess the cross-sectional association of chronotype with a diet quality score (HEI) and caloric midpoint (time of achieving 50% of total daily energy intake), considering summer holidays, using data from the National Food, Nutrition and Physical Activity Survey 2015-2016 for 578 participants (6-14 years of age). Chronotype was estimated by the midpoint of sleep and categorized as Early, Intermediate and Late, using physical activity diaries, while outcomes using two food diaries/24 h recalls. Associations of chronotype with outcomes were assessed by linear regressions adjusted for sex, age, parental education (model 1), BMI, sports practice (model 2), and summer holidays (no/yes) (model 3). In model 2, a Late vs. Early chronotype was negatively associated with HEI (β ˆ = -0.74; 95% CI: -1.47, -0.07) and positively with caloric midpoint (β ˆ = 0.35; 95% CI: 0.02, 0.69). However, associations lost significance in model 3. The association between chronotype and dietary habits may be benefit from being studied considering school terms and summer holidays. Future larger prospective studies are needed to clarify the role of summer holidays on this inter-relationship.

The effects of social jetlag and sleep variability on sleepiness in a population-based study: The mediating role of sleep debt

Sleepiness is a multicausal condition, and previous research has highlighted associations between this symptom and the circadian timing system, specifically concerning social jetlag and sleep variability. Recent inquiries have shown that the effects of social jetlag on sleepiness can be confounded with the consequences of sleep debt. In light of the current evidence, we aimed to assess the effects of social jetlag and sleep variability on sleepiness and the potential mediating role of sleep debt. We used data from the EPISONO study, a cross-sectional population-based study with a sample size of 1042 participants, representative of the city of Sao Paulo, Brazil. Participants completed the UNIFESP Sleep Questionnaire (self-reported bedtime and get-up time) and the Epworth Sleepiness Scale (subjective daytime sleepiness). Subsequently, sleep-corrected mid-sleep time (chronotype), total sleep time, social jetlag (absolute difference between the mid-sleep time on workdays and mid-sleep time on free days), sleep variability (standard deviation of mid-sleep time), and sleep debt (difference between total sleep time on workdays and free days) were calculated. Generalised linear models were used to test whether social jetlag and sleep variability affected sleepiness. Mediation models were used to determine if any observed significant effects were mediated by sleep debt. The prevalence of social jetlag was 23% for >1 h and 12% for >2 h. The mean sleep variability was 41 ± 30 min. Social jetlag had a significant effect on the Epworth Sleepiness Scale scores. This association was no longer statistically significant after controlling for age, sex, body mass index, work schedule, and chronotype. A significant indirect effect of social jetlag on sleep debt and subsequently on the Epworth Sleepiness Scale scores was found. No effect of sleep variability on sleepiness could be identified. In conclusion, the association between social jetlag and sleepiness was mediated by sleep debt but was not independent of demographic, work, and chronotype variables. This study provides new evidence on the importance of circadian misalignment and sleep debt for sleep health on a population level.

Social jetlag and body mass index among shift-working nurses in Korea: A cross-sectional study

PURPOSE

Shift-working nurses must function against their natural circadian system and are, thus, bound to be detrimentally affected by social jetlag. Circadian rhythms play a crucial role in regulating homeostasis, and social jetlag may increase one's risk for obesity. Therefore, this study aimed to identify associations between social jetlag and obesity among shift-working nurses.

METHODS

This cross-sectional study included 183 nurses working rotating shifts in South Korea. Chronotype and social jetlag were measured using the Morningness-Eveningness Questionnaire and the Munich Chronotype Questionnaire for Shift-Workers, respectively. Obesity was defined as a body mass index of 25.0 or higher, which was calculated using self-reported height and weight data. The associations between chronotype, social jetlag, and obesity were investigated using multiple logistic regression analysis.

FINDINGS

A total of 183 nurses were included in the analysis (81.4% women and 80.3% single, median age = 27.00 years). Majority of the participants' (95.1%) chronotypes were moderate evening or intermediate type. The mean overall social jetlag was 3 h and 31 min. The odds for obesity were 8.44 times higher among shift-working nurses whose social jetlag was over 3 h and 31 min (95% confidence interval: 1.66-42.99) while controlling for chronotype, exercise time, and eating habits.

CONCLUSIONS

Social jetlag may increase the likelihood of obesity among rotating shift-working nurses.

IMPLICATIONS FOR NURSING PRACTICE

To achieve positive outcomes for promoting nurses' health, upper nursing management should consider individual nurses' social jetlag when scheduling shifts. In addition, nursing managers should have the responsibility to educate nurses involved in shift work about the adverse effects of social jetlag.

Lifestyle factors, dietary patterns, and social determinants of social and eating jetlag: A cross-sectional survey

Social jetlag (SJL) and, more recently, eating jetlag have been linked with an increased risk of non-communicable diseases. Here we aim to investigate lifestyle factors (diet, eating behavior, smoking, perceived stress, time spent sedentary/day) and social determinants (education level, employment status, and place of residence) associated with SJL corrected for sleep duration (SJLsc) and eating jetlag. Self-declared data on age, gender, lifestyle, and eating behavior were collected online from March 2021 to February 2022 of 432 adults. Principal component analysis was used to extract three dietary patterns (Prudent, Western, and Risky). Prevalence of SJLsc was 35.2%, with no significant difference between men and women (p = 0.558). Adults with SJLsc had significantly larger eating jetlag (56.0 min vs 41.2 min, p = 0.001). Increasing SJLsc duration was associated with an increased adherence to a Risky dietary pattern (standardized β coefficient = .165, p = 0.012); increasing eating jetlag duration was associated with an increased adherence to a Western dietary pattern (standardized β coefficient = .127, p = 0.039) and a shorter sleep duration (standardized βcoefficient = -0.147, p = 0.011). Among social determinants analyzed, only being a student or employed was associated with eating jetlag (standardized β coefficient = 0.125, p = 0.044), while none displayed any relationship with SJLsc. Our survey provides evidence on a risky behavior among young persons with SJLsc and eating jetlag, characterized by a higher alcohol consumption, and a diet rich in processed meat and high-fat food, eating during nights, and shorter sleep duration with potential long-term negative health outcomes.

Emergence of different dimensions of sleepiness in a general population sample: An EPISONO study

INTRODUCTION

Recent evidence supports the idea that sleepiness has several dimensions, comprising psychophysiological phenomena, such as sleep propensity and sleepiness perception. The Epworth Sleepiness Scale (ESS) is among one of the most used sleepiness assessment tools, but recent data suggest that it might not detect problematic impairments in sleep health. More research is warranted investigating sleepiness dimensions with large sample sizes, using both objective and subjective methods of analyzing sleep.

METHODS

We used data from the Epidemiological Sleep Study (EPISONO), a major study carried out in Brazil using a representative sample of 1042 participants of the general population of Sao Paulo city, who completed questionnaires and underwent type I polysomnography. Sleepiness was measured by the ESS (sleep propensity) and the UNIFESP Sleep Questionnaire, which asked about the frequency of feeling sleepy during the day (sleepiness perception). The participants were distributed into 4 groups in respect of excessive daytime sleepiness (EDS) according to the following criteria: 1) having an ESS score >10 (ESS group). 2) feeling sleepy ≥3 times per week (Frequent EDS group). 3) the combined criteria (Combined EDS group). 4) having no evidence of EDS (no EDS group). The UNIFESP Sleep Questionnaire was used to obtain self-reported sleep duration, sleep debt, and sleep duration variability. Participants also completed the Pittsburgh Sleep Quality Index, the Insomnia Severity Index, and a pre-polysomnography sleep questionnaire.

RESULTS

After removing participants with missing data, there were 620 participants with no EDS, 255 individuals in the ESS group, 68 in the Frequent EDS group, and 73 in the Combined EDS group. Compared to the no EDS group, the ESS and Combined EDS groups had significantly increased sleep efficiency, diminished sleep latency, wake after sleep onset, and self-reported weekly sleep duration. The Frequent and Combined EDS groups had significantly higher scores in the Insomnia Severity Index and Pittsburgh Sleep Quality Index. All EDS groups had an increased likelihood of nonrestorative sleep. EDS frequency and the ESS scores were significantly correlated.

CONCLUSIONS

Participants with a high sleep propensity had a profile suggesting prior sleep deprivation, while high sleepiness perception was associated with impaired sleep quality. These findings indicated that, in the general population, these instruments evaluated separate sleepiness dimensions with different associations, highlighting that screening using a combination of instruments might be more effective in detecting impairments in sleep health.

Exploring the relationship between social jetlag with gut microbial composition, diet and cardiometabolic health, in the ZOE PREDICT 1 cohort

PURPOSE

In this study, we explore the relationship between social jetlag (SJL), a parameter of circadian misalignment, and gut microbial composition, diet and cardiometabolic health in the ZOE PREDICT 1 cohort (NCT03479866).

METHODS

We assessed demographic, diet, cardiometabolic, stool metagenomics and postprandial metabolic measures (n = 1002). We used self-reported habitual sleep (n = 934) to calculate SJL (difference in mid-sleep time point of ≥ 1.5 h on week versus weekend days). We tested group differences (SJL vs no-SJL) in cardiometabolic markers and diet (ANCOVA) adjusting for sex, age, BMI, ethnicity, and socio-economic status. We performed comparisons of gut microbial composition using machine learning and association analyses on the species level genome bins present in at least 20% of the samples.

RESULTS

The SJL group (16%, n = 145) had a greater proportion of males (39% vs 25%), shorter sleepers (average sleep < 7 h; 5% vs 3%), and were younger (38.4 ± 11.3y vs 46.8 ± 11.7y) compared to the no-SJL group. SJL was associated with a higher relative abundance of 9 gut bacteria and lower abundance of 8 gut bacteria (q < 0.2 and absolute Cohen's effect size > 0.2), in part mediated by diet. SJL was associated with unfavourable diet quality (less healthful Plant-based Diet Index), higher intakes of potatoes and sugar-sweetened beverages, and lower intakes of fruits, and nuts, and slightly higher markers of inflammation (GlycA and IL-6) compared with no-SJL (P < 0.05 adjusted for covariates); rendered non-significant after multiple testing adjustments.

CONCLUSIONS

Novel associations between SJL and a more disadvantageous gut microbiome in a cohort of predominantly adequate sleepers highlight the potential implications of SJL for health.

Chrononutrition and metabolic health in children and adolescents: a systematic review and meta-analysis

CONTEXT

Obesity has emerged as a global health issue for the pediatric population, increasing the need to investigate physiopathological aspects to prevent the appearance of its cardiometabolic complications. Chrononutrition is a field of research in nutritional sciences that investigates the health impact of 3 different dimensions of feeding behavior: regularity of meals, frequency, and timing of food intake.

OBJECTIVE

We carried out a systematic review and meta-analysis to investigate the association between chrononutrition in children and adolescents and the risk of overweight/obesity or a cluster of metabolic abnormalities related to glucose and lipid metabolism, blood pressure, and cardiovascular disease risk.

DATA EXTRACTION

A literature search was performed using PubMed, EMBASE, and The Cochrane Library for relevant articles published before August 2022.

DATA ANALYSIS

A total of 64 articles were included in the narrative synthesis (47 cross-sectional and 17 cohort studies), while 16 studies were included in the meta-analysis. Meta-analysis showed that non-daily breakfast consumers (≤6 d/wk) had a higher risk of overweight/obesity (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.08-1.82] compared with daily breakfast eaters (7 d/wk). Similarly, irregular breakfast consumption (only 0-to-3 times/wk) increased the risk of abdominal obesity (waist-to-height ratio ≥ 0.5) compared with regular consumption (5-to-7 times/wk) (OR, 1.38; 95% CI, 1.26-1.49). There was evidence to suggest that a regular frequency of meal consumption (≥4 times/d) is preventive against overweight/obesity development compared with fewer meals (≤3 times/d) (OR, 0.83; 95% CI, 0.70-0.97). In the narrative synthesis, snacking habits showed controversial results, while food timing was the most understudied dimension.

CONCLUSION

Overall, our data indicate a potential implication of chrononutrition in affecting pediatric metabolic health; however, the evidence of this association is limited and heterogeneous. Further prospective and intervention studies with a consistent approach to categorize the exposure are needed to elucidate the importance of chrononutrition for pediatric metabolic health.

Social jetlag and dietary intake: A systematic review

The objective of the current systematic review was to critically review the available evidence regarding the link between social jetlag and diet among the general population using observational studies. Electronic databases, including PubMed, Scopus, and ISI Web of Sciences were searched systematically. We reviewed 348 references, of which 17 studies met inclusion criteria with a total sample size of 28,905. Qualitative analysis indicated a negative association between social jetlag and adherence to healthy eating habits, including a negative association with empirically-derived healthy dietary patterns, Japanese dietary patterns, Baltic Sea dietary patterns, and the Mediterranean diet, as well as a positive association with Meat and Starchy dietary pattern. On the other hand, the findings on the link of social jetlag with food groups and nutrients were mixed and controversial, except for a more consistent increase in sugar-sweetened beverages, total fat, and saturated fat intake. Our results indicate a possible link between social jetlag and dietary intake. Research suggests that individuals experiencing greater social jetlag exhibit reduced adherence to a healthy eating pattern. However, it is important to note that the reported association lacks consensus, emphasizing the need for additional longitudinal studies to gain further insights into this matter."

An Examination of the Associations between Nutritional Composition, Social Jet Lag and Temporal Sleep Variability in Young Adults

While dietary intake has previously been related to various indices of poor sleep (e.g., short sleep duration, poor sleep quality), to date, few studies have examined chrononutrition from the perspectives of the relationship between dietary intake and social jet lag and temporal sleep variability. Moreover, recently it has been suggested that previous methods of measuring social jet lag have the potential to lead to large overestimations. Together, this precludes a clear understanding of the role of nutritional composition in the pathophysiology of poor sleep, via social jet lag and temporal sleep variability, or vice versa. The aim of the present study was to determine the relationships between nutrient intake and social jet lag (using a revised index, taking account of intention to sleep and sleep onset and offset difficulties), and temporal sleep variability. Using a cross-sectional survey, 657 healthy participants (mean age 26.7 ± 6.1 years), without sleep disorders, were recruited via an online platform and completed measures of weekly dietary intake, social jet lag, temporal sleep variability, stress/sleep reactivity and mood. Results showed limited associations between nutritional composition and social jet lag. However, levels of temporal sleep variability were predicted by consumption of polyunsaturated fats, sodium, chloride and total energy intake. The results suggest further examinations of specific nutrients are warranted in a first step to tailoring interventions to manage diet and temporal variabilities in sleep patterns.

Circadian rhythms, gut microbiota, and diet: Possible implications for health

AIMS

Over the past years, interest in chrono-nutrition has grown enormously as the fundamental role of circadian rhythms in regulating most physiological and metabolic processes has become clearer. Recently, the influence of circadian rhythms on the gut microbiota (GM) composition has also emerged, as more than half of the total microbial composition fluctuates rhythmically throughout the day. At the same time, other studies have observed that the GM itself synchronises the host's circadian biological clock through signals of a different nature. Therefore, it has been hypothesised that there is a two-way communication between the circadian rhythms of the host and the GM, but researchers have only just begun to identify some of its action mechanisms. The manuscript aim is, therefore, to gather and combine the latest evidence in the field of chrono-nutrition with the more recent research on the GM, in order to investigate their relationship and their potential impact on human health.

DATA SYNTHESIS

Considering current evidence, a desynchronization of circadian rhythms is closely associated with an alteration in the abundance and functionality of the gut microbiota with consequent deleterious effects on health, such as increased risk of numerous pathologies, including cardiovascular disease, cancer, irritable bowel disease, and depression. A key role in maintaining the balance between circadian rhythms and GM seems to be attributed to meal-timing and diet quality, as well as to certain microbial metabolites, in particular short-chain fatty acids.

CONCLUSIONS

Future studies are needed to decipher the link between the circadian rhythms and specific microbial patterns in relation to different disease frameworks.

The association of dietary approaches to stop hypertension (DASH) and Mediterranean diet with mental health, sleep quality and chronotype in women with overweight and obesity: a cross-sectional study

PURPOSE

Mental and sleep disorders are global public health problems, especially in Middle Eastern countries, and are significantly associated with circadian rhythm. This study sought to investigate the association between the dietary approaches to stop hypertension (DASH) and Mediterranean diet scores and mental health, sleep quality, and circadian rhythm.

METHODS

We enrolled 266 overweight and obese women, and depression, anxiety, and stress scale (DASS) score, Pittsburgh Sleep Quality Index (PSQI), and Morning-Evening Questionnaire (MEQ), were assessed. The Mediterranean and DASH diet score was measured using a validated semi-quantitative Food Frequency Questionnaire (FFQ). The physical activity was evaluated using the International Physical Activity Questionnaire (IPAQ). Analysis of variance and analysis of covariance, chi-square, and multinomial logistic regression tests were used as appropriate.

RESULTS

Our results showed that there was a significant inverse association between adherence to the Mediterranean diet and mild and moderate anxiety scores (p < 0.05). In addition, there was an inverse association between adherence to the DASH diet and the risk of severe depression and extremely severe stress scores (p < 0.05). Moreover, higher adherence to both dietary scores was associated with good sleep quality (p < 0.05). There was a significant relationship between circadian rhythm and the DASH diet (p < 0.05).

CONCLUSION

A significant association exists between a DASH and Mediterranean diet with sleep status, mental health, and chronotype in women of childbearing age with obesity and overweight.

LEVEL OF EVIDENCE

Level V, Cross-sectional observational study.

Breakfast Frequency and Sleep Quality in College Students: The Multiple Mediating Effects of Sleep Chronotypes and Depressive Symptoms

Sleep disorders, which are prominent problems among college students, may be associated with skipping breakfast. Therefore, we aimed to explore the role of sleep chronotypes and depressive symptoms as mediators in the relationship between breakfast frequency and sleep quality. A cross-sectional survey enrolling random samples of 712 college students was conducted by the Questionnaire Star online platform. Statistical description and correlation analysis were performed by SPSS 25.0, and a chain mediation test was performed by model 6 in PROCESS 3.5. The result of the article demonstrated that breakfast frequency can affect sleep quality through two mediating pathways: ① sleep chronotypes, with a mediating effect of 32%; and ② depressive symptoms, with a mediating effect of 52.4%. However, the chain mediating effects of sleep chronotypes and depressive symptoms was not significant, and neither was the direct effect of breakfast frequency on sleep quality. Breakfast frequency can indirectly affect sleep quality by adjusting sleep chronotypes and depressive symptoms. Regular breakfast can increase morning and intermediate sleep chronotypes, reduce depressive symptoms, and thus improve sleep quality.

Effects of Irregular Mealtimes on Social and Eating Jet Lags among Japanese College Students

College students' social and eating jet lags and chronotypes may be related to irregular eating habits. Therefore, we examined the relationship between social and eating jet lags, chronotypes, variability in first and last mealtimes, and non-eating duration, as well as the effects of snacking between dinner and bedtime on social and eating jet lags, chronotypes, and mealtime variation. A total of 1900 Japanese male college students were recruited in this study. Mean wake-up time, bedtime, sleeping time, first and last mealtimes, snacks between meals, non-eating duration, the midpoint of non-eating duration, social and eating jet lags, and chronotype were calculated. Standard deviations in first and last mealtimes, the midpoint of non-eating duration, and the coefficient of variation in non-eating duration were used to evaluate mealtime variations. Mealtime variations were significantly associated with social and eating jet lags, chronotype, the midpoint of non-eating duration, and the difference in first and last mealtime between school holidays and class days. Chronotype and the midpoint of non-eating duration were significantly delayed with increased snacking after dinner. Mealtime variations were significantly lower in those who avoided snacking than in those who did not. Thus, social and eating jet lags and chronotypes are associated with sleep habits and mealtime irregularities.

Weight status of working adults: The effects of eating misalignment, chronotype, and eating jetlag during mandatory confinement

This study aimed to examine the association between chronotype, eating jetlag, and eating misalignment with weight status among Malaysian adults during the COVID-19 restriction. This online cross-sectional study included 175 working adults recruited from March to July 2020. The chronotype was assessed using Morningness Eveningness Questionnaire (MEQ) while eating jetlag and mealtime variability were measured using Chrononutrition Profile Questionnaire (CPQ). Multiple linear regression demonstrated that lower breakfast frequency (β=-0.258, p = .002) and longer eating duration (β = 0.393, p < .001) were associated with later first eating events on workfree days. Both intermediate (β = 0.543, p < .001) and evening chronotypes (β = 0.523, p = .001) tend to eat their first meals later compared to morning person. Similar patterns were observed for overall eating jetlaggers in which lower breakfast frequency (β=-0.022, p = .011), longer eating duration (β = 0.293, p < .001), intermediate chronotype (β = 0.512, p < .001), and evening chronotype (β = 0.495, p = .003) were associated with eating later meals on workfree days. Additionally, higher BMI was also associated with eating later meals on workfree days (β = 0.181, p = .025). During movement restriction, discrepancies of mealtimes during work and workfree days offer new insight into modern eating habits that can influence weight status and general eating habits such as breakfast skipping and total daily eating duration. Population meal timing variability was affected during movement restrictions, and it was closely related to weight status.

Time-related meal patterns and breakfast quality in a sample of Iranian adults

BACKGROUND

Some evidence shows that meal timing is associated with diet quality. We aimed to investigate the relationship between meal timing and breakfast quality in a sample of Iranian adults.

METHODS

This cross-sectional study was conducted on 850 men and women living in Tehran, Iran. Dietary data was recorded by three non-consecutive 24-h dietary recalls. The Breakfast Quality Index (BQI) was calculated. Time-related meal patterns included the interval between the first and last meal (eating and fasting window), frequency of meals, length of sleep, and time of first and last eating occasion. The multiple linear regression analysis was used to identify the relationships between time-related meal patterns and BQI.

RESULTS

The mean (95% CI) of BQI was 4.52 (4.45-4.65) and the maximum was 8. Bread, cheese, vegetables, fruits, energy, and carbohydrate intake showed positive associations with BQI scores. Longer fasting time showed a positive association with fruits (β (CI 95%)) (0.11 (0.0003-0.005), and vegetable consumption (0.12 (0.009-0.07)) and BQI score (0.39 (0.001-0.06)). Time of first eating occasions indicated a negative association with protein and fat intake and BQI score. Time of last eating occasions showed a positive association with vegetables consumption and BQI score. The longer length of sleep was associated with a higher BQI score. The frequency of meals was significantly and positively related to energy and macronutrients intake and BQI.

CONCLUSION

Earlier first and last meal, longer sleep length, longer fasting window, and a greater meal frequency were associated with a better breakfast quality.

Chronotype Differences in Body Composition, Dietary Intake and Eating Behavior Outcomes: A Scoping Systematic Review

The timing and nutritional composition of food intake are important zeitgebers for the biological clocks in humans. Thus, eating at an inappropriate time (e.g., during the night) may have a desynchronizing effect on the biological clocks and, in the long term, may result in adverse health outcomes (e.g., weight gain, obesity, and poor metabolic function). Being a very late or early chronotype not only determines preferred sleep and wake times but may also influence subsequent mealtimes, which may affect the circadian timing system. In recent years, an increased number of studies have examined the relation between chronotype and health outcomes, with a main focus on absolute food intake and metabolic markers and, to a lesser extent, on dietary intake distribution and eating behavior. Therefore, this review aimed to systematically determine whether chronotype indirectly affects eating behaviors, dietary intake (timing, choice, nutrients), and biomarkers leading to body composition outcomes in healthy adults. A systematic literature search on electronic databases (PubMed, CINAHL, MEDLINE, SCOPUS, Cochrane library) was performed (International Prospective Register of Systematic Reviews number: CRD42020219754). Only studies that included healthy adults (aged >18 y), classified according to chronotype and body composition profiles, using outcomes of dietary intake, eating behavior, and/or biomarkers, were considered. Of 4404 articles, 24 met the inclusion criteria. The results revealed that late [evening type (ET)] compared with early [morning type (MT)] chronotypes were more likely to be overweight/obese with poorer metabolic health. Both MT and ET had similar energy and macronutrient intakes, consuming food during their preferred sleep-wake timing: later for ET than MT. Most of the energy and macronutrient intakes were distributed toward nighttime for ET and exacerbated by unhealthy eating behaviors and unfavorable dietary intakes. These findings from our systematic review give further insight why higher rates of overweight/obesity and unhealthier metabolic biomarkers are more likely to occur in ET.

Variability in Sleep Timing and Dietary Intake: A Scoping Review of the Literature

The objective of this scoping review was to summarize previous studies which examined the effect of day-to-day variability in sleep timing and social jetlag (SJL) on dietary intake. A systematic literature search was conducted in PubMed, Embase, and Clarivate Analytics Web of Science and we identified 22 records. No difference in caloric and macronutrient intake between SJL groups was observed in studies that enrolled healthy young adults. However, studies that enrolled participants with obesity and obesity-related chronic conditions reported a higher caloric intake and a higher intake of carbohydrates, total fat, saturated fats, and cholesterol in participants with SJL than in those without. Most studies reported a lower quality of diet, a delayed mealtime, and eating jetlag in participants with SJL vs. those without SJL. No correlation of day-to-day variability in sleep timing with average caloric intake was observed, but bed-time variability was negatively associated with diet quality. Methodological issues have been identified in sources assessed including study design, power calculation, population enrolled, and tools/metrics used for sleep timing variability assessment. Future well powered longitudinal studies, with clear protocols, standardized metrics, including all age groups from general population are needed to clarify the dietary intake consequences of variability in sleep timing.

Role of chronotype in dietary intake, meal timing, and obesity: a systematic review

CONTEXT

Recent studies show that dietary habits and obesity seem to be influenced by chronotype, which reflects an individual's preference for the timing of sleeping, eating, and activity in a 24-hour period.

OBJECTIVE

This review aimed to analyze the association of chronotype with dietary habits, namely energy and macronutrient intakes, meal timing, and eating patterns, as well as with obesity.

DATA SOURCES

PubMed/MEDLINE, LILACS, and Google Scholar databases were searched between 2004 and 2020. Study selection was performed by 2 authors independently; disagreements on eligibility of articles were resolved by a third author. After assessment of 12 060 abstracts, 43 studies (21 articles on obesity; 13 on food consumption, meal timing, and eating patterns; and 9 that addressed both obesity and dietary behavior) were included.

DATA EXTRACTION

A standard form was used to extract study design, country, number of participants, method of chronotype determination, and main findings.

DATA ANALYSIS

Approximately 95% of included studies showed an association between eveningness and at least 1 unhealthy eating habit. Morningness was associated with regular consumption of fresh and minimally processed foods. In addition, about 47% of studies showed a higher association between late types and obesity.

CONCLUSION

Late types are more likely to present unhealthy eating habits, such as eating late at night, skipping breakfast often, and eating processed/ultraprocessed foods, while early types are more likely to have healthy and protective habits, such as eating early and eating predominantly fresh/minimally processed foods. Intermediate types tend to have a pattern of health and eating more similar to early types than to late types. Late types are also more likely to present higher weight and body mass index than early or intermediate types.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021256078.

The association between social jetlag and parameters of metabolic syndrome and type 2 diabetes: a systematic review and meta‐analysis

This study aims to determine the association between social jetlag and parameters of metabolic syndrome and type 2 diabetes (T2D) in a systematic review and meta-analysis. A systematic literature search was conducted in PubMed/Embase/Scopus until May 2022. Included studies described an association between social jetlag and parameters of the metabolic syndrome and/or T2D, were available full text and written in English or Dutch. Data extraction and quality assessment were performed on pre-piloted forms independently by two reviewers. Results were meta-analysed using random-effects analysis. A total of 6,290 titles/abstracts were screened, 176 papers were read full-text, 68 studies were included. Three studies were rated as low quality, 27 were moderate, and 38 were high quality. High quality studies showed that having social jetlag compared to no social jetlag was significantly associated with higher body mass index in 20 studies (0.49 kg/m² , 95% confidence interval [CI] 0.21-0.77; I²  = 100%), higher waist circumference in seven studies (1.11 cm, 95% CI 0.42-1.80; I²  = 25%), higher systolic blood pressure in 10 studies (0.37 mmHg, 95% CI 0.00-0.74; I²  = 94%) and higher glycated haemoglobin in 12 studies (0.42%, 95% CI 0.12- 0.72; I²  = 100%). No statistically significant associations were found for obesity, abdominal obesity, high- and low-density lipoprotein levels, cholesterol, triglycerides, diastolic blood pressure, hypertension, fasting glucose, homeostatic model assessment for insulin resistance, metabolic syndrome or T2D. Sensitivity analyses did not reduce heterogeneity. Despite substantial heterogeneity, social jetlag is associated with certain parameters of the metabolic syndrome and T2D, but not with prevalent metabolic syndrome or T2D. These findings should be interpreted with caution as the level of evidence is low and mostly based on cross-sectional data. Longitudinal studies are needed to further assess the direction of causality.

Associations among social jetlag, sleep-related characteristics, premenstrual symptoms, depression, and body mass index of female nursing students

PURPOSE

This study aimed to identify the predictors of female nursing students' body mass index (BMI), including social jetlag.

DESIGN AND METHODS

This secondary data analysis of a cross-sectional survey conducted in 2015 included data of 304 female undergraduate nursing students. A hierarchical regression analysis was performed to identify the predictors of BMI.

FINDINGS

Social jetlag was the most potent predictor of BMI, followed by premenstrual symptoms and sleep quality.

PRACTICE IMPLICATIONS

This study presents foundational data for developing interventions for social jetlag management as a strategy to prevent obesity in female nursing students by identifying factors predicting BMI.

Morning chronotype is associated with higher adherence to the Mediterranean diet in a sample of Italian adults

BACKGROUND AND AIMS

A growing body of evidence has associated subjects with an evening chronotype with worse eating behaviours and poorer diet quality. However, only few studies have investigated the relationship between chronotype and Mediterranean diet (MD). The aim of this study was to better understand the chronotype influence on dietary habits and MD adherence in a large sample of Italian adults.

METHODS AND RESULTS

A total of 1247 participants (66.7% women) with a mean age of 36.1 ± 14.6 years were included in the analysis. Chronotype was classified as morning in 35.6% of subjects, intermediate in 56.7%, and evening in 7.1%. Regarding meal frequency, evening subjects showed a significantly (p < 0.05) greater tendency to skip breakfast (20.5%) than morning (6.9%) and intermediate (12%) subjects. Similarly, evening subjects were found to skip mid-morning snack more often than morning subjects (59.1% vs. 47.1%; p = 0.04), and lunch more often than intermediate subjects (8% vs. 2.8%; p = 0.01). In addition, all meals were eaten by evening subjects at a significantly delayed time, except for lunch. As to MD adherence a significant (p < 0.001) higher adherence in morning subjects (10.1 ± 2.2) compared to intermediate (9.5 ± 2.1) and evening (9.5 ± 2.2) subjects was observed. At a logistic regression analysis adjusted for possible confounding factors, morning subjects showed an increased probability (OR 1.54, 95%CI 1.19-1.99; p < 0.001) of being in the highest MD adherence tertile.

CONCLUSION

Chronotype was associated with MD adherence. In particular, morning subjects showed higher MD adherence than intermediate and evening subjects.

Association of Japanese Breakfast Intake with Macro- and Micronutrients and Morning Chronotype

(1) Background: Dietary intake may have a remarkable effect on sleep because skipping breakfast and having a late dinner affects many sleep parameters. Breakfast is the most important meal of the day for children and adults to maintain morning chronotype. We examine whether breakfast style is associated with nutrient intake and sleep factors. (2) Methods: This cross-sectional analysis, with a large sample size of 2671 (766 men and 1805 women aged 20–60 years after data brush-up), was based on data obtained from an online survey. Correlation analysis was performed using Spearman’s rank correlation test. The Kruskal–Wallis’s test followed by post hoc Dunn’s multiple comparison test was used to evaluate the interaction between sleep factors and breakfast categories. Multiple regression analyses were performed to identify variables associated with multiple confounding factors. Dietary data were analyzed using approximately one-month average dietary records from the application. The basic characteristics of the participants (age, sex, and BMI) and other lifestyle-related factors (sleep and physical activity) were obtained accordingly. Sleep parameters including the timing of weekday sleep onset, weekday wake-up, weekend (free day) sleep onset, weekend wake-up, sleep, and midpoints of sleep phase were calculated for each participant. We categorized participants’ breakfast types into five groups: (1) Japanese meal, where breakfast may contain Japanese ingredients such as rice; (2) Western meal, where breakfast may contain bread; (3) alternating eating patterns of Japanese and Western meals; (4) cereals and supplements, where breakfast may contain cereals or supplements and energy bars; and (5) skipped breakfast (no breakfast). (3) Results: The midpoint values of the sleep phase on weekends adjusted for sleep debt on work days (MSFsc) related to chronotype were higher in women, suggesting that they may prefer eveningness. Participants with obesity, young age, and low physical activity preferred eveningness with longer sleep durations. Intake of Japanese-style breakfast was significantly associated with early wake-up time on both weekdays and weekends. Cereal-style breakfast intake was significantly associated with late wake-up on both weekdays and weekends. Intake of macronutrients such as protein, fat, carbohydrate, and sodium at breakfast time was positively and strongly associated with the intake of Japanese breakfast, whereas macronutrients were negatively associated with the intake of cereal breakfast. Among micronutrients, vitamin K was positively correlated with Japanese breakfast and negatively correlated with cereal breakfast; (4) Conclusions: Japanese-style breakfast is associated not only with morning preference but also with high intake of macro- and micronutrients.

Social jet lag and eating styles in young adults

Social jet lag refers to circadian misalignment that occurs when people shift their sleep schedules from weekdays to weekends. Social jet lag is linked with numerous negative health outcomes, with emerging research connecting social jet lag to increased consumption of unhealthy foods. Existing research has not yet examined the associations between social jet lag and eating styles (e.g., emotional eating). Emotional eating and loss of control over eating are problematic eating styles which may lead to overeating and weight gain. Conversely, intuitive eating is associated with positive health outcomes such as lower risk of obesity. The present study examined social jet lag and eating styles in a young adult sample, as emerging adulthood is an important developmental time period for establishing healthy sleep and eating habits. Results of the current study indicated that in a sample of 372 American undergraduate participants, social jet lag significantly predicted lower intuitive eating (β = -.129, p = .012) and greater emotional eating (β = .12, p = .022) when controlling for age, sex, and chronotype. It was marginally predictive of loss of control over eating (β = .102, p = .050). Sleep quantity on weekdays (not weekends) also significantly predicted intuitive eating (p = .017) and loss of control over eating (p = .044), and sleep quality significantly predicted intuitive eating (p < .001), emotional eating (p < .001), and loss of control over eating (p < .001). These findings extend our understanding of the relationship between social jet lag and eating styles in college students. Addressing social jet lag in this population is an important consideration for their cardiometabolic health and for reducing weight fluctuations.

Time-Related Eating Patterns Are Associated with the Total Daily Intake of Calories and Macronutrients in Day and Night Shift Workers

The aim of the study was to investigate whether time-related eating patterns are associated with the daily intake of calories and macronutrients in Brazilian male military police officers (n = 81; 29-day and 52-night workers; mean age: 36.4 ± 0.9 and 38.5 ± 0.7 years, respectively). Energy and macronutrient intake were determined by a non-consecutive 3-day food recall. Time-related eating patterns, such as the time of the first and the last meals, eating duration, and caloric midpoint, were evaluated. Individuals were classified as “early” or “late” eaters according to the median caloric midpoint. Night shift workers showed a later eating time for the last meal (p < 0.001), longer eating duration (p < 0.001), and later caloric midpoint (p = 0.037) than day workers. Late eaters from both workgroups consumed more 24 h energy (p = 0.028), fat in calories (p = 0.006) and protein (calories: p < 0.001; percentage of total calories: p = 0.042), and less carbohydrates in calories (p = 0.010) intake than early eaters. The time of the first meal was negatively correlated with 24 h energy (p = 0.024) and carbohydrate (p = 0.031) intake only in day workers. The time of the last meal was positively correlated with 24 h energy (day workers: β = 0.352; p = 0.044; night workers: β = 0.424; p = 0.002) and protein (day workers: β = 0.451; p = 0.013; night workers: β = 0.536; p < 0.001) intake for both shift workers, and with carbohydrate (β = 0.346; p = 0.016) and fat (β = 0.286; p = 0.042) intake only in night workers. Eating duration was positively correlated with energy (day workers: β = 0.473; p = 0.004; night workers: β = 0.320; p = 0.023) and carbohydrate (day workers: β = 0.418; p = 0.011; night workers: β = 0.364; p = 0.010) intake in both groups. Thus, time-related eating patterns indicative of intake later at night are associated with increased daily energy and macronutrient intake.

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.

Life before and after COVID-19: The 'New Normal' Benefits the Regularity of Daily Sleep and Eating Routines among College Students

After the COVID-19 lockdown, a 'new normal' was established, involving a hybrid lifestyle that combined face-to-face with virtual activity. We investigated, in a case-control study, the impact of the 'new normal' on daily sleep and eating routines, compared with pre-pandemic conditions. To do this, we propose using social and eating jet lag as markers of the regularity in daily routines. Additionally, we studied whether the 'new normal' had an impact on the body mass index (BMI), diet quality, and other health-related variables. This study included 71 subjects in the pre-pandemic group, and 68 in the 'new normal' group (20-30 years). For all participants, we evaluated social and eating jet lag, BMI, diet and sleep quality, eating behaviors, physical activity, and well-being. General linear models were used to compare outcome variables between pre-pandemic and 'new normal' groups. The results revealed that the 'new normal' was associated with greater regularity in daily sleep and eating routines (-0.7 h of social jet lag (95% CI: -1.0, -0.4), and -0.3 h of eating jet lag (95% CI: -0.5, -0.1)), longer sleep duration on weekdays (1.8 h (95% CI: 1.5, 2.2)), and lower sleep debt (-1.3 h (95% CI: -1.7, -0.9)). Regarding BMI and other health-related variables, we observed that these variables were similar between 'new normal' and pre-pandemic groups. These findings indicate that the 'new normal' had a positive impact on daily sleep and eating routines. Additionally, our results indicated that the 'new normal' offered college students a more sustainable lifestyle, which was associated with more hours of sleep during the week and lower sleep debt. This, in the long run, could have a positive impact on BMI and overall health.

The Impact of Weekday-to-Weekend Sleep Differences on Health Outcomes among Adolescent Students

The sleep difference between weekdays and weekends can lead to negative physical and mental health outcomes in adolescents. Thus, this study has attempted to analyze the impact of sleep time differences on various health outcomes, using nationally representative panel data. Data from the junior high school student panel of the Korean Children and Youth Panel Survey were analyzed. The sleep difference was defined as the difference between the average sleep duration on weekdays and that on weekends in minutes. A series of mixed effect linear regression models for continuous variables or mixed effect logit regression for binary variables was utilized. Korean adolescent students reported from 96.8 min to 133.2 min of sleep duration difference between weekdays and weekends. After controlling for gender, parent work status, and type of housing, the weekday-to-weekend sleep differences were associated with various health-related outcomes including concentration difficulty, aggression, somatic symptoms, and withdrawal. Additionally, adolescent student life satisfaction was associated with sleep difference. The sleep differences among adolescent students were more associated with mental health-related outcomes and emotional symptoms than with physical health-related outcomes. The appropriate intervention to reduce the sleep difference gap is an important key to improve health in the adolescence period.

Emotional eating and cognitive restraint mediate the association between sleep quality and BMI in young adults

This cross-sectional study was designed to investigate whether diet quality and eating behaviors could mediate the association between sleep quality and body mass index (BMI) in young adults. For all participants (n = 925; aged 21.4 ± 2.5 years; 77.8% women) we evaluated: BMI, sleep quality, diet quality, and eating behavior dimensions (emotional eating, cognitive restraint, and uncontrolled eating). Linear regression models were used to test associations between exposure and outcome variables. Path analysis was conducted with all potential mediators and covariates entered at the same time. Results showed that emotional eating (β = 0.04 [95% CI: 0.03; 0.06]), cognitive restraint (β = 0.03 [95% CI: 0.01; 0.04]), uncontrolled eating (β = 0.02 [95% CI: 0.01; 0.04]) and diet quality (β = -0.14 [95% CI: 0.19;-0.08]) were significantly associated with sleep quality. Additionally, BMI was significantly associated with PSQI score (β = 0.09 [95% CI: 0.01; 0.17]), emotional eating (β = 0.89 [95% CI: 0.60; 1.18]), and cognitive restraint (β = 1.37 [95% CI: 1.02; 1.71]). After testing for mediation, results revealed that emotional eating and cognitive restraint evidenced a significant mediating effect on the association between sleep quality and BMI. Additionally, diet quality was significantly associated with emotional eating (β = -0.35 [95% CI: 0.56;-0.13]), cognitive restraint (β = 0.53 [95% CI: 0.27; 0.79]), and uncontrolled eating (β = -0.49 [95% CI: 0.74;-0.25]). In conclusion, young adults with poor sleep quality are more likely to deal with negative emotions with food, which, in turn, could be associated with higher cognitive restraint, becoming a vicious cycle that has a negative impact on body weight. Our results also emphasize the role of eating behaviors as determinants of diet quality, highlighting the importance of considering sleep quality and eating behaviors when designing obesity prevention strategies in this population.

Social Jetlag and Related Risks for Human Health: A Timely Review

The term social jetlag is used to describe the discrepancy between biological time, determined by our internal body clock, and social times, mainly dictated by social obligations such as school or work. In industrialized countries, two-thirds of the studying/working population experiences social jetlag, often for several years. Described for the first time in 2006, a considerable effort has been put into understanding the effects of social jetlag on human physiopathology, yet our understanding of this phenomenon is still very limited. Due to its high prevalence, social jetlag is becoming a primary concern for public health. This review summarizes current knowledge regarding social jetlag, social jetlag associated behavior (e.g., unhealthy eating patterns) and related risks for human health.

The relationship between diet and sleep in 2-y-old children: Results from Growing Up in New Zealand

OBJECTIVES

This study aimed to examine the relationship between dietary practices and sleep in young children.

METHODS

In this study, 2-y-old children (n = 6327) and their mothers were enrolled at birth and during pregnancy, respectively. The study obtained maternal demographic, health, and lifestyle data during late pregnancy. Parents reported the 2-y-old child's dietary practices on a food frequency questionnaire, as well as sleep duration and night-waking frequency. Measures of dietary intake quantified servings per day for each food group (grouped as low/moderate/high intake). Sleep measures were as inadequate sleep when <11 h sleep in a 24-h period and increased night waking when waking ≥2 times per night. Multivariable logistic regression analyses examined associations between toddler diet and sleep, which were described using adjusted odds ratios (ORs) and 95% confidence intervals.

RESULTS

In this study, 2-y-old children (n = 6288) slept for a mean of 12.3 hours (standard deviation: ±1.5 hours) over a 24-h period, with 734 children (12%) getting <11 h of sleep in 24 h. Increased night waking occurred in 1063 children (17%). Compared with low intake, high soft drink/snack/fast food intake was associated with inadequate sleep (OR: 1.37) and increased night waking (OR: 1.34). High milk/cheese/yoghurt intake (OR: 1.55) was associated with increased odds of night waking, but moderate (OR: 0.81) or high (OR: 0.78) vegetable intake was associated with decreased odds of night waking. Exposure to screens (OR: 1.28) and heavy maternal cigarette smoking (OR: 2.20) were also associated with inadequate sleep and increased night waking, respectively.

CONCLUSIONS

At age 2 y, higher consumption of soft drinks/snacks/fast foods is associated with shorter, more disrupted sleep. Conversely, higher vegetable consumption is associated with less disrupted sleep. Dietary modifications may improve toddlers' sleep.

Is chronotype associated with dietary intake and weight gain during pregnancy? A prospective and longitudinal study

OBJECTIVES

The effects of chronotype on dietary intake and weight gain during pregnancy have not been addressed in the literature. The aim of this study was to analyze the effect of chronotype on eating patterns, energy, and macronutrient intake and distribution, as well as weight gain during pregnancy.

METHODS

This was a prospective cohort study carried out with 100 pregnant women in the first, second, and third gestational trimesters. Dietary intake was assessed by three 24-h dietary recalls in each trimester, totaling nine recalls. Energy and macronutrient intake and distribution were evaluated at meals throughout the day. Chronotype was derived from midsleep time on free days, and the scores obtained were categorized into tertiles. Recommendations from the Institute of Medicine were used to assess the adequacy of weight gain. Generalized estimating equation models were used to determine the effects of chronotype and gestational trimester on eating patterns, daily energy, macronutrient distribution, and weight gain.

RESULTS

Pregnant women with values for midsleep time on free days indicative of eveningness have breakfast later and also have higher energy and carbohydrate intake at dinner than "morning" women. Pregnant "morning" women showed better diet quality in terms of milk and dairy and saturated fat. Also, despite the tendency for all tertiles to gain excess weight during pregnancy, we found that pregnant women with a tendency to eveningness had worse adequacy of gestational weight gain in the third trimester than "morning" women (2.24 ± 0.25 versus 1.22 ± 0.14, P < 0.001).

CONCLUSION

Pregnant women with a tendency to eveningness consume breakfast later in the day and exhibit greater consumption of energy and carbohydrates in the evening, as well as a worse standard of gestational weight gain in the third trimester. Our results emphasize the importance of considering chrononutrition variables in prenatal nutritional guidelines to promote maternal and fetal health.

Social Jetlag Is Associated With Impaired Metabolic Control During a 1-Year Follow-Up

Previous studies have identified social jetlag (SJL) as a risk factor for non-communicable chronic diseases (NCCDs), but its association with metabolic control over time is unclear in the literature. Therefore, we examined the influence of SJL on metabolic parameters and blood pressure (BP) in patients with NCCDs over a 1-year follow-up. This retrospective, longitudinal study included 625 individuals (age: 56.0 +12.0 years; 76% female) with NCCDs [type 2 diabetes mellitus (TD2), systemic arterial hypertension (SHA), obesity, or dyslipidemia]. SJL was calculated based on the absolute difference between mid-sleep time on weekends and weekdays. Current metabolic parameters and BP of the patients were compared with data from a year prior. Generalized estimating equations (GEE) and multiple linear regression analyses were used to examine the association among SJL, metabolic parameters, and BP. Multiple linear regression analyses adjusted for confounders showed that SJL was positively associated with the delta difference of fasting glucose (β = 0.11, p = 0.02) and triglyceride levels (β = 0.09, p = 0.04) among all subjects with NCCDs, and with fasting glucose (β = 0.30, p = 0.0001) and triglyceride levels (β = 0.22, p = 0.01) in the TD2 group. GEE analysis demonstrated an isolated effect of SJL on diastolic BP. High SJL impaired clinical and metabolic control in individuals with NCCDs, leading to a worse profile after a 1-year follow-up, particularly among type II diabetics.

Circadian misalignment measured by social jetlag from early to late pregnancy and its association with nutritional status: a longitudinal study

A mismatch between circadian and social clocks leads to a circadian misalignment, which has been widely measured by social jetlag (SJL). There are several studies measuring SJL, but it has not been studied in pregnant women. Therefore, this study aimed to identify the occurrence of SJL throughout pregnancy and to verify whether there is an effect of pre-pregnancy body mass index (BMI) on SJL throughout pregnancy. The baseline of the present study was conducted with 205 1st trimester pregnant women of whom 100 were followed in their 2nd and 3rd trimester. SJL was calculated based on the absolute difference between mid-sleep time on workdays versus work-free days. The pre-pregnancy BMI and current BMI (kg/m²) were calculated. Linear regression and Generalised Estimating Equation (GEE) adjusted for confounders were used to determine the association between SJL and the gestational trimesters (time), and anthropometric variables. Most of the pregnant women (54.5%) presented SJL > 1 h in the first gestational trimester. We also found an isolated effect of the gestation trimester on the SJL mean. In this sense, pregnant women had a decrease in SJL from the second to the third trimester (1.33 ± 0.08 versus 1.12 ± 0.07, respectively; p = 0.012). GEE analyzes showed that pregnant women of a normal weight showed a decrease in SJL from the second to the third trimester (1.29 ± 0.11 and 0.93 ± 0.08, respectively, p = 0.032), but this was not found in the other groups of nutritional status (underweight, overweight and obesity). In addition, a positive association between SJL and pre-gestational BMI in the third trimester (β = 0.200, p = 0.046) was found. SJL is quite prevalent during the gestational period and excessive BMI both before and during pregnancy is associated with an increased risk of having SJL > 1 h in the third and second trimesters, respectively. In addition, pregnant women of normal weight—but not underweight or overweight—had decreased SJL from the second to the third trimester.

The impact of circadian timing on energy balance: an extension of the energy balance model

A significant proportion of the population is classified as having overweight or obesity. One framework which has attempted to explain biobehavioral mechanisms influencing the development of overweight and obesity is the energy balance model. According to this model, the body continually attempts to balance energy intake with energy expenditure. When energy intake and energy expenditure become imbalanced, there is an increase in homeostatic and allostatic pressure, generally to either increase energy intake or decrease energy expenditure, so as to restore energy homeostasis.Recent research has indicated that circadian aspects of energy intake and energy expenditure may influence energy balance. This paper provides a narrative review of existing evidence of the role of circadian timing on components of energy balance. Research on the timing of food intake, physical activity, and sleep indicates that unhealthy timing is likely to increase risk of weight gain. Public health guidelines focus on how much individuals eat and sleep, what foods are consumed, and the type and frequency of exercise, but the field of circadian science has begun to demonstrate that when these behaviors occur may also influence overweight and obesity prevention and treatment efforts.

Do Rotating Night Shifts Change Nurses' Nutritional Status? A Cross-Sectional Study

OBJECTIVE

Shift work disrupts circadian rhythms through environmental factors such as disruption of the light-dark and rest-activity cycle. This study aims to evaluate the nutritional status, circadian phenotype, sleep quality, and anthropometric measurements in nurses working in rotating night shifts.

METHOD

The study included 44 nurses working in rotating night shifts. Physical activity records for 4 days and 24-hour dietary recalls for 7 days were taken. To evaluate the circadian phenotypes and sleep quality, the Morningness-Eveningness Questionnaire and the Pittsburg Sleep Quality Index were used, respectively.

RESULTS

Most nurses were evening chronotype and had poor sleep quality. Shift work was associated with higher daily energy intake and lower total daily energy expenditure (p < 0.05). On the night shifts, while fiber-rich foods such as beans and fruit consumption decrease, the consumption of fats, sweets, and cereals increases. While carbohydrates, total fat, and cholesterol intake were higher in only women on the night shift (p < 0.05), saturated fat and calcium intake were higher in all nurses (p < 0.05). While the water intake of the nurses was lower on the night shift (p < 0.05), tea intake was higher in women (p < 0.05). A correlation was found between total shift work duration, body mass index (r = 0.525), waist circumference (r = 0.577), waist-height ratio (r = 0.584), and body fat percentage (r = 0.513) (p < 0.001).

CONCLUSIONS

Nurses should be encouraged to ensure adequate water intake and to make healthy food choices during the night shift to maintain health and work performance.

Association of sleep duration on workdays or free days and social jetlag with job stress

AIM

The aim of this study was to investigate the impact of sleep problems on job stress in office workers.

METHODS

This study included 4645 office workers from 29 companies who completed the study questionnaires between April 2017 and April 2019 in Japan. Sleep duration was assessed based on the participants' subjective sleep schedule on workdays and free days. The midpoint of sleep on free days (sleep-corrected) and social jetlag were calculated in accordance with the Munich Chronotype Questionnaire. To assess job stress, we used the 57-item Brief Job Stress Questionnaire.

RESULTS

Multivariate logistic regression analysis revealed that the following factors were significantly associated with high job stress in office workers: a sleep duration <6 h on workdays (OR = 1.77, 95% CI = 1.46-2.15, P < 0.001), a sleep duration <6 h on free days (OR = 1.40, 95% CI = 1.05-1.87, P = 0.022), a sleep duration of at least 8 h on free days (OR = 1.31, 95% CI = 1.06-1.60, P = 0.011), and more than 2 h of social jetlag (OR = 1.33, 95% CI = 1.04-1.70, P = 0.022).

CONCLUSION

This study suggests that insufficient sleep, long sleep durations on free days, and social jetlag may be associated with high job stress in office workers.

A cross-sectional evaluation of the relationship between social jetlag and diet quality

The aim of this study was to compare anthropometric measures of obesity and sleep qualities in individuals with/without social jetlag (SJL). In addition, it was aimed to compare the energy, macronutrient intake and diet qualities of individuals with/without SJL during school and non-school days. This study comprised 710 university students with mean age 21.58 ± 1.41 years. The presence of SJL was acknowledged if there was a difference of more than 1 hour between the middle of sleep time on school day and on non-school day. While the physical activity levels (PALs) of the individuals were determined with a 24-hour physical activity record, measurements such as waist circumference, neck circumference and body mass index were recorded for anthropometric measurements. Pittsburgh Sleep Quality Index was used to determine the sleep quality of the individuals. Energy, macronutrients intake, and diet quality were calculated from the 24-h dietary recall of the individuals, and recorded for the school days and non-school days. In this study, 76% of the individuals (n = 542) were determined as exposed to SJL. Although there was no significant difference in their PALs, individuals with SJL had a higher waist (p < .05) and neck (p < .05) circumference, as well as higher body mass index (p < .05). Individuals with SJL were found to have significantly poor sleep quality (OR:1.109, p < .031) and sleep latency (OR:1.130, p < .001) after adjustment for confounding factors. When compared to school days, in the individuals with SJL, energy (p < .001), fat (p < .001), saturated fatty acids (SFA) (p < .001), and mono unsaturated fatty acids (MUFA) (p < .001) were significantly increased; however, fiber intake (p < .001) was significantly reduced on non-school days. Although there was no significant difference in the diet quality scores between the groups on the school days, the diet quality of the individuals without SJL on non-school days was increased significantly (p < .05). In conclusion, SJL was associated with sleep loss, increased body mass index, and lowered diet quality in university students.

Circadian rhythm abnormalities during the COVID-19 outbreak related to mental health in China: a nationwide university-based survey

OBJECTIVE/BACKGROUND

School closure and home quarantine has been implemented worldwide during the coronavirus disease 2019 (COVID-19) outbreak. The study aims to assess the associations of circadian rhythm abnormalities (CRA) during the COVID-19 outbreak with mental health in Chinese undergraduates.

METHODS

A nationwide cross-sectional university-based survey was conducted from 4th February to 12th, 2020. Based on different geographical locations and purposive sampling approach, 19 universities from 16 provinces or municipalities in the mainland of China were selected. A total of 14,789 participants were recruited by using multistage stratified random sampling. The data of CRA were collected by self-reported questionnaires consist of four items involved rest-activity cycle, diet rhythm, wake up rhythm and sleep rhythm. The Patient Health Questionnaire and the Generalized Anxiety Disorder were applied to evaluate the symptoms of depression and anxiety. Chi-square test and ordinal logistic regression models were used to describe the distributions and associations of CRA and mental health.

RESULTS

A total of 11,787 students [female: 6731(57.1%)] aged 15-26 years old (M = 20.45, SD = 1.76) were analyzed (response rate: 79.7%). The results showed the percentage of CRA were 17.5-28.7%. The prevalence of depression and anxiety were significantly higher in students with single CRA. Students who reported the coexistence of four CRA were more likely to be with the symptoms of depression (OR: 4.43, 95% CI: 3.91-5.03) and anxiety (OR: 3.11, 95% CI: 2.70-3.60). Dose-response relationships were found between multiple CRA and mental problems.

CONCLUSION

Circadian rhythm abnormalities are positively associated with mental health among university studies. Mental health care is needed for college students during the COVID-19 epidemic period.

Objectively measured chronotype and social jetlag are associated with habitual dietary intake in undergraduate students

This study aimed to investigate the associations between objectively measured sleep timing and habitual dietary intake among university students. We hypothesized that a later chronotype and larger social jetlag (SJL) are associated with an undesirable dietary intake. The 82 healthy university students included in this study were asked to undertake a seven-day wrist activity recording. All the participants also completed a self-administered questionnaire during the recording period, including questions on demographic characteristics and habitual dietary intakes. Dietary intake and the score for adherence to the Japanese Food Guide Spinning Top (food guide score) over the previous month were evaluated using a self-reported diet history questionnaire. Nocturnal sleep timing and total sleep time for each night were estimated using the recorded wrist activity. Chronotype was calculated as weekend (WE) mid-sleep time corrected for catch-up sleep on weekdays (WDs). SJL was calculated by subtracting WD mid-sleep time from WE mid-sleep time. Multivariable linear regression showed that a later chronotype was significantly (P < .05) associated with a lower consumption of eggs, greater consumption of grains, and lower food guide score. Multivariable linear regression also showed significant (P < .05) associations of a larger value in SJL with a lower total energy intake, lower consumption of grains, and greater consumption of sugar and confectioneries. The results suggest that chronotype and SJL may be differently associated with undesirable dietary intake in young adults. These findings have important implications for developing novel strategies, focusing on sleep timing, for improving dietary intakes and preventing lifestyle-related diseases.

A scoping review of chronotype and temporal patterns of eating of adults: tools used, findings, and future directions

Circadian rhythms, metabolic processes and dietary intake are inextricably linked. Timing of food intake is a modifiable temporal cue for the circadian system and may be influenced by numerous factors, including individual chronotype - an indicator of an individual's circadian rhythm in relation to the light-dark cycle. This scoping review examines temporal patterns of eating across chronotypes and assesses tools that have been used to collect data on temporal patterns of eating and chronotype. A systematic search identified thirty-six studies in which aspects of temporal patterns of eating, including meal timings; meal skipping; energy distribution across the day; meal frequency; time interval between meals, or meals and wake/sleep times; midpoint of food/energy intake; meal regularity; and duration of eating window, were presented in relation to chronotype. Findings indicate that, compared with morning chronotypes, evening chronotypes tend to skip meals more frequently, have later mealtimes, and distribute greater energy intake towards later times of the day. More studies should explore the difference in meal regularity and duration of eating window amongst chronotypes. Currently, tools used in collecting data on chronotype and temporal patterns of eating are varied, limiting the direct comparison of findings between studies. Development of a standardised assessment tool will allow future studies to confidently compare findings to inform the development and assessment of guidelines that provide recommendations on temporal patterns of eating for optimal health.

Chronic disruption of circadian rhythm with mistimed sleep and appetite - an exploratory research

This research aimed to explore the relation of social jetlag (SJL) with perceived appetite, and hormones involved in hunger regulation in healthy subjects in free-living conditions (study registration number: ACTRN12618001182280). Eighty normally diurnally active men and women were enrolled in 4 study groups according to the presence of SJL and sleep deprivation (2 groups with SJL with or without sleep deprivations and 2 groups without SJL with or without sleep deprivation) matched 1:1:1:1 for age, gender, and body mass index. Appetite was assessed in fasting state, by measuring acylated ghrelin level and using 100 mm visual analog scales. Persons with SJL had a higher perceived appetite for pork, poultry, fish, eggs, milk, and dairy products and higher acylated ghrelin levels than those without SJL. When considering the presence of sleep deprivation, subjects with SJL, with and without sleep deprivation, reported a higher perceived appetite than group with sleep deprivation alone. They also reported later meal times for lunch and dinner, had more frequently a snack before sleep and reported eating more frequently while watching TV or playing on computer, suggesting poorer eating habits in these subjects. In conclusion, independent of sleep duration, SJL is associated with an increased appetite for caloric dense food, suggesting an increased incentive value of food in these subjects and an anticipated pleasure of ingesting these foods.

Sleep Debt and Social Jetlag Associated with Sleepiness, Mood, and Work Performance among Workers in Japan

Although sleep debt and social jetlag (SJL) influence daytime dysfunctions, the effects of both sleep debt and SJL on them have not been analyzed. The aim of this study was to examine the mutual relationship between sleep debt and SJL on daytime sleepiness, mood, and work performance. This study was a cross-sectional study on sleep health conducted on the Japanese general population. A total of 4505 general workers (30% female, aged 43.57 ± 11.63 years) were selected and analyzed. Sleep debt was defined by sleep debt index (SDI), which is the discrepancy between desired and real sleep duration. SJL and SDI scores exhibited a positive but weak coefficient (r = 0.19). In a 4 (SJL) × 3 (SDI) two-way ANOVA, the interaction effects were notable for sleepiness and depression scores, while the group effects were notable for the work performance score. For sleepiness and depression scores, SDI >2 h was not significantly different from SJL. In addition, the impact of SDI was higher than that of SJL on sleepiness (β = 0.17), depression (β = 0.16), and work performance (β = -0.10). The impact of sleep debt was more pronounced than SJL on daytime dysfunctions, although both sleep debt and SJL have negative impacts on them.

Social Jetlag Is Associated with the Frequency of Consumption of Sugar-Sweetened Beverages and a High BMI Percentile in Adolescents: Results of the Cross-Sectional Family Life, Activity, Sun, Health, and Eating (FLASHE) Study

BACKGROUND

Social jetlag (SJL) occurs in adolescents due to misalignment of the biological and social clocks, so that most teens wake up earlier than their biological clocks on weekdays and delay bedtime and wake up time on weekends. This shift in sleep timing among adolescents is associated with an adverse endocrine and behavioral risk profile, in addition to increased food consumption and increased body mass index (BMI).

OBJECTIVE

The aim of this study was to determine the association between SJL, and the frequency of consumption of multiple food and beverage groups and BMI percentile in adolescents.

DESIGN

Publicly available data from the cross-sectional Family Life, Activity, Sun, Health, and Eating (FLASHE) study were analyzed.

PARTICIPANTS

Participants from the FLASHE study were recruited from all regions of the United States between April and October 2014. Among the 1,581 adolescents aged 12 through 17 years in the original study, 1,556 with complete sleep data were analyzed.

MAIN OUTCOME MEASURES

The difference between the frequency of dietary consumption according to the Dietary Screener Questionnaire and BMI percentile was assessed in adolescents grouped according to SJL, as follows: no SJL: less than 1-hour difference; mild SJL: 1- to 2-hour difference; and severe SJL: more than 2-hour difference.

STATISTICAL ANALYSES PERFORMED

Differences in the frequency of food consumption were analyzed using the Kruskal-Wallis test. Secondary outcomes were analyzed using logistic regression models.

RESULTS

Daily consumption frequency of sugar-sweetened beverages and fruits and vegetables differed among the 3 groups. Likewise, the BMI percentile differed among the 3 groups and was highest in the severe SJL group. Those in the severe SJL group had a 1.84-fold higher probability of having overweight or obesity (95% CI 1.83 to 1.84) than those in the no SJL group.

CONCLUSIONS

Severe SJL is associated with a higher frequency of sugar-sweetened beverage consumption and higher odds of having overweight or obesity compared with no SJL in adolescents.

The mediating effect of conscientiousness on the academic consequences of social jetlag

Social jetlag (SJL) causes impairment of academic achievement; on the other hand, the personality factor of conscientiousness is related to better grades. We evaluated the impact of conscientiousness on the academic consequences of social jetlag. Undergraduate students (n = 556) were evaluated throughout their first 3 years of university education. Conscientiousness, as a mediating factor in the structural equation modeling, explained 20% of the effect of SJL on academic achievement. This is the first cohort study to evaluate the mediating effect of personality on the consequences of SJL.