Chronotype: Implications for Epidemiologic Studies on Chrono-Nutrition and Cardiometabolic Health

Time of Dietary Energy and Nutrient Intake and Body Mass Index in Children: Compositional Data Analysis from the Childhood Obesity Project (CHOP) Trial

Meal timing is suggested to influence the obesity risk in children. Our aim was to analyse the effect of energy and nutrient distributions at eating occasions (EO), including breakfast, lunch, supper, and snacks, on the BMI z-score (zBMI) during childhood in 729 healthy children. BMI and three-day dietary protocols were obtained at 3, 4, 5, 6, and 8 years of age, and dietary data were analysed as the percentage of the mean total energy intake (TEI; %E). Intakes at EOs were transformed via an isometric log-ratio transformation and added as exposure variables to linear mixed-effects models. Stratified analyses by country and recategorization of EOs by adding intake from snacks to respective meals for further analyses were performed. The exclusion of subjects with less than three observations and the exclusion of subjects who skipped one EO or consumed 5% energy or less at one EO were examined in sensitivity analyses. Around 23% of the children were overweight at a given time point. Overweight and normal-weight children showed different distributions of dietary intakes over the day; overweight children consumed higher intakes at lunch and lower intakes of snacks. However, no significant effects of timing of EOs on zBMI were found in regression analyses.

Associations between the timing of different foods’ consumption with cardiovascular disease and all-cause mortality among adults with sleep disorders

Introduction

People with sleep disorders are under disrupted biological rhythms. Whether changing the timing of specific food consumption contributes to decreasing cardiovascular and all-cause risk is unknown.

Methods

A total of 8,005 participants with sleep disorders were selected from the U.S. National Health and Nutrition Examination Survey (NHANES) from 2005 to 2014. Cox proportional hazards regression models were used to analyze the relationship between the consumption time of foods and cardiovascular disease (CVD) and all-cause death. Moreover, equivalent food substitution models were carried out to evaluate the alterations in the risk of CVD mortality for the changed food intake time.

Results

After adjusting for multiple confounders, participants who consume red and orange vegetables, starchy vegetables, and fermented dairy in the morning (hazard ratio (HR)_{red and orange vegetables} = 0.45, 95% CI: 0.26–0.81; HR_{starchy vegetables} = 0.47, 95% CI: 0.25–0.88; HR_{fermented dairy} = 0.57, 95% CI: 0.36–0.89) and milk and eggs in the evening contribute to reducing the likelihood of death from CVD (HR_milk = 0.65, 95% CI: 0.43–0.96; HR_eggs = 0.72, 95% CI: 0.53–0.98). Iso-calorically switching 0.1 serving of starchy vegetable and fermented dairy and milk intake from one period to another does significantly reduce the mortality risk of CVD.

Conclusion

Higher intake of red and orange vegetables, starchy vegetables, and fermented dairy in the morning and milk and eggs in the evening confers a lower risk of CVD among individuals with sleep disorders.

Relative Validity of Food Intake in Each Meal Type and Overall Food Intake Derived Using the Meal-Based Diet History Questionnaire against the 4-Day Weighed Dietary Record in Japanese Adults

We examined the relative validity of food intake for each meal type (breakfast, lunch, dinner, and snacks) and overall food intake obtained through the Meal-based Diet History Questionnaire (MDHQ). In total, 222 Japanese adults (111 for each sex) aged 30–76 years completed the web version of the MDHQ and then the 4-non-consecutive-day weighed dietary record (DR). The number of major food groups (n = 24 in total) for which no statistically significant difference was observed between median intakes estimated using the DR and MDHQ ranged from 8 (snacks) to 12 (dinner) among women, and from 8 (breakfast) to 13 (lunch) among men. The median values of the Spearman’s correlation coefficients between the MDHQ and DR estimates ranged from 0.28 (dinner) to 0.54 (breakfast) among women, and from 0.24 (dinner) and 0.60 (breakfast) among men. Bland–Altman analyses generally showed wide limits of agreement and proportional bias. Similar results were obtained using the paper version of the MDHQ, which was completed after conducting the DR. In conclusion, the MDHQ has a satisfactory ability to estimate median intake and rank individuals according to consumption for many food groups, despite a limited ability to estimate food group intakes on an individual level.

Association between chronotype, sleep pattern, and eating behaviours in a group of Italian adults

A cross-sectional study was conducted to assess the possible relationship between chronotype, sleeping, and eating patterns in 74 Italian adults (71.6% women). Based on Morningness-Eveningness Questionnare (MEQ) score, participants were classified as morning (n = 24), intermediate (n = 25), and evening (n = 25) chronotypes. From analysis, no significant differences among chronotypes emerged for sleep habits. As to eating behaviours, the evening subjects showed a significant (p < 0.05) shift towards later hours of the day in the consumption of all meals, except dinner. In addition, the evening subjects had a later midpoint of energy intake (EI) of about 35 min and 1 h (p < 0.001), respectively, than the intermediate and morning subjects. Analysing the diet quality, morning subjects reported significantly (p = 0.030) lower consumption of sweets and sweeteners, and significantly (p = 0.035) lower intake of ultra-processed fats and seasonings. Evening subjects showed a significant delay in EI during the day, while morning subjects reported a better-quality diet.

The Effect of Personality on Chrononutrition during the COVID-19 Lockdown in Qatar

The COVID-19 lockdown has had a significant impact on people’s lives worldwide. This study aimed to investigate the effect of personality on chrononutrition during the COVID-19 lockdown. Using a cross-sectional design, a convenient sample of 543 adults in Qatar completed an online questionnaire using validated tools to assess personality and chrononutrition behaviors during the first COVID-19 lockdown. Participants scoring high in openness were more likely to eat at night (mean difference (MD) = 0.41, 95% confidence interval (CI): 0.10, 0.72) compared to those scoring high in agreeableness, while those scoring high in extraversion and openness had a shorter eating window (MD = −76.6, 95%CI: −146.3, −6.93 and MD = −29.8, 95%CI: −56.5, −3.01, respectively). Participants high in extraversion had longer evening latency (MD = 66.3, 95%CI: 25.4, 107.3) and evening eating (MD = −62.0, 95%CI: −114.0, −9.0) compared those high in agreeableness. Participants high in conscientiousness showed evidence of first eating event misalignment during the weekend (MD = 22.0, 95%CI: 0.15, 43.9) and last eating event misalignment during weekdays (MD = −27.8, 95%CI: −47.3, −8.41) compared to those high in agreeableness. Lastly, participants high in openness showed evidence of eating window misalignment during the weekend (MD = 30.6, 95%CI: 5.01, 56.2). This study suggests that personality traits can inform personalized nutritional approaches when aiming for healthy habits during unexpected periods, such as the COVID-19 pandemic.

Perspectives: on Precision Nutrition Research in Heart, Lung, and Blood Diseases and Sleep Disorders

The release of the 2020-2030 Strategic Plan for NIH Nutrition Research (SPNR) and its emphasis on precision nutrition has provided an opportunity to identify future nutrition research that addresses individual variability in response to diet and nutrition across the life span-including those relevant to the Strategic Vision of the National Heart, Lung, and Blood Institute (NHLBI). The SPNR and the NHLBI's Strategic Vision were developed with extensive input from the extramural research community, and both have 4 overarching strategic goals within which are embedded several objectives for research. For the SPNR, these include 1) spur discovery science and normal biological functions (e.g., role of the microbiome in health and disease), 2) population science to understand individual differences (e.g., biomarkers including 'omics that predict disease status), 3) emerging scientific areas of investigation and their application (e.g., data science, artificial intelligence), and 4) cross-cutting themes (e.g., training the scientific workforce and minority health and health disparities). These strategic goals and objectives serve as blueprints for research and training. Nutrition remains important in the prevention and treatment of heart, lung, blood, and sleep (HLBS) disorders and diseases, and the NHLBI has played a pivotal role in supporting nutrition research. In this paper, we report important gaps in the scientific literature related to precision nutrition in HLBS diseases. Research opportunities that could stimulate precision nutrition and their alignment with the SPNR and the NHLBI Strategic Vision Objectives are provided. These opportunities include 1) exploring individual differences in response to varying dietary patterns and nutrients; 2) investigating genetic/epigenetic, biological (e.g., microbiome, biomarkers), social, psychosocial, and environmental underpinnings of individual variability in diet; 3) elucidating the role of circadian rhythm and chrononutrition; and 4) applying implementation science research methods in precision nutrition interventions relevant to HLBS diseases.

Meal-specific dietary patterns and their contribution to habitual dietary patterns in the Iranian population

Recent studies have focused on habitual intake without addressing meal-specific intakes. We aimed to identify meal-specific dietary patterns and their contribution to habitual dietary patterns. This cross-sectional study was conducted on 838 adults, both sexes who attended the health centres in Tehran. Dietary data were recorded by three 24-h dietary recalls (24hDR). Dietary patterns were identified by using principal component analysis on meal-specific and overall food intakes. Intraclass correlation (ICC) was used as a measurement of consistency across meals and days. Correlation analysis and linear regression (partial R2) were used for meals contribution. Four habitual dietary patterns were derived from average dietary intake of 3-d 24hDR labelled as 'Western', 'Healthy', 'Traditional' and 'Legume and broth'. Also, we identified two major dietary patterns on each meal level (factor 1 and 2 for breakfast, lunch, afternoon snack and dinner). The highest contribution of energy intake was observed in lunch (25·7 %), followed by dinner (20·81 %). Consistency of food groups was the highest across days (ICC tea = 0·58) and breakfasts (ICC tea = 0·60). Dinner had a strong correlation coefficient with the 'Western' habitual dietary pattern then followed by lunch. Similarly, dinner and lunch contributed the most (r and partial R2) to the 'Western' habitual dietary pattern. Our results suggest that habitual dietary patterns to several extents are formed at meal levels, and dinner has a greater contribution to the habitual dietary patterns in Iranian people. This may help planning for local dietary guidelines according to the time of eating to promote public health.

Characterisation, procedures and heritability of acute dietary intake in the Twins UK cohort: an observational study

Background

Estimated food records (EFR) are a common dietary assessment method. This investigation aimed to; (1) define the reporting quality of the EFR, (2) characterise acute dietary intake and eating behaviours, (3) describe diet heritability.

Methods

A total of 1974 one-day EFR were collected from 1858 participants in the TwinsUK cohort between 2012 and 2017. EFR were assessed using a six-point scoring system to determine reporting quality. The frequency and co-occurrence of food items was examined using word clouds and co-occurrence networks. The impact of eating behaviours on weight, BMI and nutrient intake were explored using mixed-effect linear regression models. Finally, diet heritability was estimated using ACE modelling.

Results

We observed that 75% of EFR are of acceptable reporting quality (score > 5). Black tea and semi-skimmed milk were the most consumed items, on an individual basis (respectively 8.27, 6.25%) and paired (0.21%) as co-occurring items. Breakfast consumption had a significantly (p = 5.99 × 10^− 7) greater impact on energy (kcal) (mean 1874.67 (±SD 532.42)) than skipping breakfast (1700.45 (±SD 620.98)), however only length of eating window was significantly associated with body weight (kg) (effect size 0.21 (±SD 0.10), p = 0.05) and BMI (effect size 0.08 (±SD 0.04), p = 0.04) after adjustment for relevant covariates. Lastly, we reported that both length of eating window (h2 = 33%, CI 0.24; 0.41), and breakfast consumption (h2 = 11%, CI 0.02; 0.21) were weakly heritable.

Conclusions

EFR describing acute dietary intake allow for eating behaviour characterisation and can supplement habitual diet intake assessments. Novel findings of heritability warrant further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-022-00763-3.

Late chronotypes, late mealtimes. Chrononutrition and sleep habits during the COVID-19 lockdown in Italy

The emerging field of chrononutrition provides useful information on how we manage food intake across the day. The COVID-19 emergency, and the corresponding restrictive measures, produced an unprecedented change in individual daily rhythms, possibly including the distribution of mealtimes. Designed as a cross-sectional study based on an online survey, this study aims to assess the chrononutrition profiles (Chrononutrition Profile Questionnaire, CP-Q) in a sample of 1298 Italian participants, during the first COVID-19 lockdown, and to explore the relationship with chronotype (reduced Morningness-Eveningness Questionnaire, rMEQ), sleep quality (Pittsburgh Sleep Quality Index, PSQI) and socio-demographics. Our findings confirm a change in eating habits for 58% of participants, in terms of mealtimes or content of meals. Being an evening chronotype and experiencing poor sleep imply a higher likelihood of changing eating habits, including a delay in the timing of meals. Also, under these unprecedented circumstances, we report that the timing of breakfast is a valuable proxy capable of estimating the chronotype. From a public health perspective, the adoption of this straightforward and low-cost proxy of chronotype might help in the early detection of vulnerable subgroups in the general population, eventually useful during prolonged stressful conditions, as the one caused by COVID-19 pandemic.

Meal Timing and Macronutrient Composition Modulate Human Metabolism and Reward-Related Drive to Eat

The ‘time-of-day’ modifies the metabolic response to meals, but less data exist on the diurnal variations in the hedonic drive to eat. In the present paper, we evaluate the effects of meal timing and macronutrient composition on metabolic responses and the homeostatic vs. hedonic regulation of appetite. In study 1, 84 young, healthy adults completed an online computer-based task assessing the homeostatic and hedonic drive to eat in the morning and evening. In study 2, 24 healthy, young men received 2 identical (850 kcal each) meals in the morning (8:45 h) and evening (18:00 h), of 2 experimental conditions: (i) regular carbohydrate (CH) meals (regular-CH), and (ii) high carbohydrate (high-CH) meals, containing 50 and 80% of energy from CHs, respectively. Serial blood samples were obtained, and the postprandial feelings of hunger, satiety, wanting and liking were assessed. Study 1 revealed a higher hedonic drive to eat in the evening compared to the morning. Study 2 confirmed this diurnal pattern of hedonic appetite regulation and, moreover, showed increased glucose and insulin responses to the evening meal. Postprandial ghrelin and leptin as well as feelings of hunger and satiety were not different between the mealtimes nor between the macronutrient conditions. In line with this, the homeostatic drive to eat was neither affected by the mealtime nor macronutrient composition. Increased the hedonic drive to eat in the evening may represent a vulnerability to palatable food and, thus, energy overconsumption. Together with lower evening glucose tolerance, these findings reflect an adverse metabolic constellation at the end of the day, especially after the ingestion of CH-rich foods.

A Time to Rest, a Time to Dine: Sleep, Time-Restricted Eating, and Cardiometabolic Health

Cardiovascular disease (CVD) poses a serious health and economic burden worldwide. Modifiable lifestyle factors are a focus of research into reducing the burden of CVD, with diet as one of the most investigated factors. Specifically, the timing and regularity of food intake is an emerging research area, with approaches such as time-restricted eating (TRE) receiving much attention. TRE involves shortening the time available to eat across the day and is associated with improved CVD outcomes compared with longer eating windows. However, studies that have examined TRE have not considered the impact of sleep on CVD outcomes despite recent evidence showing that sleep duration can influence the timing and amount of food eaten. In this article, we argue that as TRE and sleep influence each other, and influence the same cardiometabolic parameters, experiencing inadequate sleep may attenuate any positive impact TRE has on CVD. We examine the relationship between TRE and CVD, with sleep as a potential mediator in this relationship, and propose a research agenda to investigate this relationship. This will provide necessary evidence to inform future interventions aimed at reducing the burden of CVD.

Face Validity of Observed Meal Patterns Reported with 7-Day Diet Diaries in a Large Population-Based Cohort Using Diurnal Variation in Concentration Biomarkers of Dietary Intake

In a cross-sectional analysis of a population-based cohort (United Kingdom, N = 21,318, 1993-1998), we studied how associations between meal patterns and non-fasting triglyceride and glucose concentrations were influenced by the hour of day at which the blood sample was collected to ascertain face validity of reported meal patterns, as well as the influence of reporting bias (assessed using formula of energy expenditure) on this association. Meal size (i.e., reported energy content), mealtime and meal frequency were reported using pre-structured 7-day diet diaries. In ANCOVA, sex-specific means of biomarker concentrations were calculated by hour of blood sample collection for quartiles of reported energy intake at breakfast, lunch and dinner (meal size). Significant interactions were observed between breakfast size, sampling time and triglyceride concentrations and between lunch size, sampling time and triglyceride, as well as glucose concentrations. Those skipping breakfast had the lowest triglyceride concentrations in the morning and those skipping lunch had the lowest triglyceride and glucose concentrations in the afternoon, especially among acceptable energy reporters. Eating and drinking occasion frequency was weakly associated with glucose concentrations in women and positively associated with triglyceride concentrations in both sexes; stronger associations were observed for larger vs. smaller meals and among acceptable energy reporters. Associations between meal patterns and concentration biomarkers can be observed when accounting for diurnal variation and underreporting. These findings support the use of 7-day diet diaries for studying associations between meal patterns and health.

Stress Susceptibility Moderates the Relationship Between Eveningness Preference and Poor Sleep Quality in Non-Acute Mood Disorder Patients and Healthy Controls

OBJECTIVE

This study aimed to investigate the relationship between eveningness preference and poor sleep quality and eventually examine the moderation effect of stress susceptibility.

METHODS

Individuals with non-acute major depressive disorder or bipolar affective disorder and healthy participants were recruited. The Composite Scale of Morningness (CSM) and the Pittsburgh Sleep Quality Index (PSQI) were used to evaluate chronotype and sleep quality, respectively. Eysenck Personality Questionnaire, Tridimensional Personality Questionnaire, Perceived Stress Scale, and Beck Anxiety Inventory were used to formulate stress susceptibility and as indicator variables for empirical clustering by latent class analysis (LCA). Linear regression models were used to examine the relationship between chronotype preference and sleep quality. The interaction terms of CSM and stress susceptibility were examined for the moderation effect.

RESULTS

A total of 887 individuals were enrolled in this study, with 68.2% female and 44.1% healthy participants. Three subgroups were derived from LCA and designated as low stresssusceptibility (40.2%), moderate stress susceptibility (40.9%), and high stress susceptibility (18.8%) groups. After controlling for covariates, the CSM scores inversely correlated with PSQI scores [b (se)=-0.02 (0.01), p=0.01], suggesting that individuals with eveningness preferences tend to have poor sleep quality. Moreover, stress susceptibility moderated the relationship between CSM and PSQI scores (p for interaction term = 0.04). Specifically, the inverse association between CSM and PSQI was more robust in the high stress susceptibility group than that in the low stress susceptibility group.

CONCLUSION

Eveningness preference was associated with poor sleep quality, and this relationship was moderated by stress susceptibility.

Changes in chronotype and social jetlag during adolescence and their association with concurrent changes in BMI-SDS and body composition, in the DONALD Study

BACKGROUND/OBJECTIVES

Adolescence is a critical period for both the development of overweight and the transition toward a later chronotype, often accompanied by an increase in social jetlag. This study assessed whether changes in chronotype and social jetlag, are linked to changes in body composition during adolescence.

SUBJECTS/METHODS

We used data from the DONALD open cohort study, collected between 2014 and 2019, from 213 adolescents (9-17 years at baseline, 45% females) having at least two measures of chronotype and anthropometry (N = 572). Chronotype was assessed with the Munich Chronotype Questionnaire and defined as: midpoint of sleep corrected for sleep-debt (MSFsc) accumulated over the week (later MSFsc represents later chronotype). Social jetlag (SJL) defines the difference between midpoint of sleep during week and weekend. Calculations for Fat Free Mass Index (FFMI [kg/m²)]) and Fat Mass Index (FMI) [kg/m²)]) were based on body fat percentage, weight, and height. To analyze the associations, we used linear mixed-effect regression models. Finally, the total cohort was split into three biologically relevant age groups (cut-off set at <12 years, ≥12 to ≤15 years and >15 years).

RESULTS

Median follow-up was 2.1 years. Overall, change toward a later chronotype was significantly related with an increase in FMI (ß: 0.05, 95% CI: 0.01-0.08). A 1 h increase in social jetlag predicted an increase in BMI-SDS of 0.08 SDS units (95% CI: 0.01-0.14) and in FMI of 0.04 kg/m2 (95% CI: 0.003-0.08). Associations were stronger for the age group ≥12 to ≤15 years (p for interaction: <0.001). No relationship was found with FFMI.

CONCLUSIONS

Changes in MSFsc and SJL during adolescence were associated with concurrent changes in BMI-SDS and FMI. The age ≥12 to ≤15 years appears to be a sensitive period in which chronobiological changes were clearly associated with increasing body fatness.

Circadian rhythm disruptions: A possible link of bipolar disorder and endocrine comorbidities

Epidemiological studies have demonstrated an association between bipolar disorder (BP) and endocrine diseases. Further, circadian rhythm disruptions may be a potential common pathophysiological mechanism of both disorders. This review provides a brief overview of the molecular mechanisms of circadian rhythms, as well as roles circadian rhythms play in BP and common endocrine comorbidities such as diabetes and thyroid disease. Treatments targeting the circadian system, both pharmacological and non-pharmacological, are also discussed. The hope is to elicit new interest to the importance of circadian system in BP and offer new entry points and impetus to the development of medicine.

Association of Dietary Pattern, Lifestyle and Chronotype with Metabolic Syndrome in Elderly-Lessons from the Population-Based Hamburg City Health Study

In aging populations, the increasing prevalence of metabolic syndrome and the resulting elevated risk of developing non-communicable diseases is a major challenge for worldwide health care. The elderly population-based Hamburg City Health Study (HCHS) allows investigating the association in the relevant age group 45-74 years. For 3513 of 10,000 participants, self-reported information on dietary patterns (DASH, MEDAS), chronotype, lifestyle, and data on metabolic syndrome parameters was available. Overall, having a "low" DASH score was a statistically significant risk factor (OR 1.23; 95% CI 1.01-1.48). Only for "late" chronotype, a slightly elevated OR (1.06) was found, but no statistically significant effect on the outcome of metabolic syndrome. Still, considering chronotype vastly improved the model. However, a trend of an increasing predicted probability from early to late chronotype was found for participants with low adherence to the DASH diet. Future research should focus on options for prevention in persons with late chronotype, so they can be supported better in adherence to, e.g., DASH diet to lower their risk.

Content Validation of a Chrononutrition Questionnaire for the General and Shift Work Populations: A Delphi Study

Unusual meal timing has been associated with a higher prevalence of chronic disease. Those at greater risk include shift workers and evening chronotypes. This study aimed to validate the content of a Chrononutrition Questionnaire for shift and non-shift workers to identify temporal patterns of eating in relation to chronotype. Content validity was determined using a Delphi study of three rounds. Experts rated the relevance of, and provided feedback on, 46 items across seven outcomes: meal regularity, times of first eating occasion, last eating occasion, largest meal, main meals/snacks, wake, and sleep, which were edited in response. Items with greater than 70% consensus of relevance were accepted. Rounds one, two, and three had 28, 26, and 24 experts, respectively. Across three rounds, no outcomes were irrelevant, but seven were merged into three for ease of usage, and two sections were added for experts to rate and comment on. In the final round, all but one of 29 items achieved greater than 70% consensus of relevance with no further changes. The Chrononutrition Questionnaire was deemed relevant to experts in circadian biology and chrononutrition, and could represent a convenient tool to assess temporal patterns of eating in relation to chronotype in future studies.

Clock Time of First Eating Episode and Prospective Risk of All-Cause Mortality in US Adults

BACKGROUND

There is increasing recognition that a morning or evening preference is associated with time of eating, metabolic health, and morbidity. However, few studies have examined the association of time of eating with mortality.

OBJECTIVES

To examine the association of time of first recalled ingestive episode with the prospective risk of all-cause mortality.

METHODS

We used mortality-linked data from the NHANES conducted in 1988-1994 and 1999-2014 (n = 34,609; age ≥ 40 years). The exposure was quartiles (Q1-Q4) of clock time of first eating episode self-reported in the baseline 24-hour dietary recall. The outcome was follow-up time from the date of NHANES examination to the date of death or end of the follow-up period (31 December 2015). We used proportional hazards regression methods to determine the independent association of time of first eating episode with relative hazard of all-cause mortality, with adjustments for multiple covariates and the complex survey design. Multiple linear regression methods were used to examine the associations of time of first eating episode with baseline cardiometabolic biomarkers and dietary attributes.

RESULTS

In this national cohort, with a median age of ∼55 years (95% CI: 54.6-55.4 years) at baseline and a median follow-up of 8.3 years (IQR, 8.75 years), there were 10,303 deaths. The median times of first eating episodes in Q1-Q4 were 05:45, 07:00, 08:00, and 10:00, respectively. Covariate-adjusted relative hazards of mortality in Q1 to Q3 of the time of the first eating episode were 0.88 (95% CI: 0.81-0.96), 0.88 (95% CI: 0.81-0.95), 0.94 (95% CI: 0.87-1.02), with Q4 as the referent (P = 0.0008). Qualitative dietary attributes were inversely related with the time of the first eating episode; however, BMI and serum concentrations of glycemic biomarkers increased with later times of first eating episode (P ≤ 0.0001).

CONCLUSIONS

Recall of an earlier time of the first eating episode by ≥40-year-old US participants was suggestive of a small relative survival advantage in this observational study.

Data-driven development of the Meal-based Diet History Questionnaire for Japanese adults

FFQ, the primary method of dietary assessment in large-scale nutritional epidemiological studies, preclude an informed evaluation of the timing of dietary intake and meal-specific dietary intake. In this study, we developed the Meal-based Diet History Questionnaire (MDHQ), a self-administered questionnaire designed for estimating food and nutrient intakes for each meal type separately. The development was done based on a 16-d dietary record obtained from 242 Japanese adults. The MDHQ consisted of the three different parts, with a total of 196 items. Part 1 of the MDHQ asks about consumption frequency of generic food groups (n 24) for each meal type: breakfast, morning snack, lunch, afternoon snack, dinner and night snack. Part 2 of the MDHQ asks about relative consumption frequency of sub-food groups within one of the generic food groups which are asked in Part 1. Combining information derived from Parts 1 and 2 enables us to increase the number of foods we can estimate efficiently but within a limited number of questions. Part 3 of the MDHQ asks about general eating behaviours, which are intended to use in a variety of ways during dietary intake calculation. A series of calculation algorithms for food groups, energy and nutrients was also prepared. Given that the MDHQ was empirically developed based on comprehensive information on actual food consumption, this innovative tool may be promising for future epidemiological research on meal patterns and time of day of dietary intake, or chrono-nutrition research. A rigorous evaluation of validity of the MDHQ is warranted.

Craniopharyngioma, Chronotypes and Metabolic Risk Profile

Aim: To investigate the potential association among Craniopharyngioma (CP), chronotypes and metabolic risk profile. Subjects and Methods: The study population included 28 patients (46.4% males; 42.6 ± 15.8 years) and 28 controls, age, gender and BMI matched (46.4% males; 46.5 ± 12.9 years). In this study sample, we evaluated: anthropometric measurements (waist circumference, WC; BMI), plasma glucose, lipid profile, and systolic (SBP) and diastolic (DBP) blood pressure. Morningness-Eveningness was measured with the Horne-Ostberg Morningness-Eveningness Questionnaire (MEQ), which included 19 questions about preferred sleep time and daily performance. Results: in both patients and controls grade I obesity was detected in 15 subjects (53.6%), grade II obesity in 13 subjects (46.4%). In the patient group, the mean score of chronotype was 47.8 ± 12.6. In particular, 9 patients (32.1%) exhibited the morning chronotype, 6 (21.4%) the intermediate chronotype and 13 (46.4.%) the evening chronotype. No significant difference was found in gender and age among the chronotype categories. Patients with the evening chronotype had higher blood pressure values and worse metabolic parameters than those with the morning chronotype. In the control group, the mean score of the chronotype was 57.6 ± 9.5. In particular, 16 (57.1%) subjects exhibited the morning chronotype, 10 (35.7%) the intermediate chronotype and only 2 (7.1.%) the evening chronotype. The prevalence of intermediate and evening chronotypes was higher in females than males (p = 0.021), while males have a higher prevalence of the morning chronotype. Subjects with intermediate and evening chronotypes had worse metabolic parameters than those with the morning chronotype. In patients, the chronotype score was inversely correlated to WC, BMI, SBP, DBP, plasma glucose, total cholesterol, triglycerides, LDL cholesterol and positively correlated with HDL cholesterol. No correlation was found between age and chronotype. In controls, the chronotype score was inversely correlated to WC, BMI, plasma glucose, total cholesterol, LDL cholesterol. No correlation was found among chronotype and age, blood pressure, triglycerides, HDL cholesterol. Considering the whole population of the study (patients and controls), at logistic regression the chronotype score was significantly associated with the presence of CP. Conclusions: for the first time thus far, our study puts the light on the association of the CP with chronotypes and metabolic alterations in this disease, which are the main determinants of the reduced quality of life, higher morbidity and mortality in this setting of patients. This finding suggests that alterations of chronotype might represent an adjunctive risk for CP patients and a possible target for their integrate management.

Breakfast Skipping, Weight, Cardiometabolic Risk, and Nutrition Quality in Children and Adolescents: A Systematic Review of Randomized Controlled and Intervention Longitudinal Trials

Breakfast skipping increases with age, and an association with a high risk of being overweight (OW) and of obesity (OB), cardiometabolic risk, and unhealthy diet regimen has been demonstrated in observational studies with children and adults. Short-term intervention trials in adults reported conflicting results. The purpose of this systematic review was to summarize the association of breakfast skipping with body weight, metabolic features, and nutrition quality in the groups of young people that underwent randomized controlled (RCT) or intervention longitudinal trials lasting more than two months. We searched relevant databases (2000–2021) and identified 584 articles, of which 16 were suitable for inclusion. Overall, 50,066 children and adolescents were included. No studies analyzed cardiometabolic features. Interventions were efficacious in reducing breakfast skipping prevalence when multi-level approaches were used. Two longitudinal studies reported a high prevalence of OW/OB in breakfast skippers, whereas RCTs had negligible effects. Ten studies reported a lower-quality dietary intake in breakfast skippers. This review provides insight into the fact that breakfast skipping is a modifiable marker of the risk of OW/OB and unhealthy nutritional habits in children and adolescents. Further long-term multi-level intervention studies are needed to investigate the relationship between breakfast, nutrition quality, chronotypes, and cardiometabolic risk in youths.

Chronotype Differences in Energy Intake, Cardiometabolic Risk Parameters, Cancer, and Depression: A Systematic Review with Meta-Analysis of Observational Studies

Chronotype is a behavioral manifestation of the internal circadian clock system. It refers to the specific activity-rest preference of an individual over a 24-h period and can be assessed using different methodologies that classify individuals into morning or evening chronotype. In recent years, several studies have suggested a relation between individual chronotype, eating habits, and the risk of developing obesity and other conditions. Our aim was to evaluate the association between chronotype, energy intake, and health status through a meta-analytic approach. A comprehensive search of MEDLINE, Embase, Scopus, Web of Science, and Cochrane Database was conducted. Observational studies that reported a measure of association between chronotype, energy intake, and health indicators were considered eligible. Overall, 39 observational studies (37 cross-sectional studies, 2 prospective cohort studies) were included in the systematic review, with a total of 377,797 subjects. By comparing morning and evening subjects, pooled analyses of cross-sectional studies showed significantly (P < 0.001) higher concentrations of blood glucose [mean difference (MD): 7.82; 95% CI: 3.18, 12.45], glycated hemoglobin (MD: 7.64; 95% CI: 3.08, 12.21), LDL cholesterol (MD: 13.69; 95% CI: 6.84, 20.54), and triglycerides (MD: 12.62; 95% CI: 0.90, 24.35) in evening subjects. Furthermore, an association between evening type and the risk of diabetes (OR: 1.30; 95% CI: 1.20, 1.41), cancer (OR: 1.18; 95% CI: 1.08, 1.30), and depression (OR: 1.86; 95% CI: 1.20, 2.88) was reported. Regarding the other outcomes examined, no significant differences were observed between the groups in terms of energy intake, anthropometric parameters, blood pressure, insulin, total and HDL cholesterol, and hypertension risk. In conclusion, evening chronotype was associated with a worse cardiometabolic risk profile and higher risk of diabetes, cancer, and depression. Further studies are needed to confirm these results and to better elucidate the interplay between chronotype, nutrition, and health status. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42021231044.

Circadian preference and its relationship with possible sleep and awake bruxism in adults assisted by the public health system

Modern lifestyle and social demands induce changes in sleep routines that may not meet individual circadian preferences (chronotype). Such changes may be associated with the development of unhealthy lifestyles and the emergence of diseases relevant to public health services, such as obesity, hypertension, and diabetes mellitus, as well as sleep bruxism (SB) and awake bruxism (AB). The present study aimed to assess the relationship between the evening, morning or intermediate chronotypes with the report of possible SB and AB in adult individuals assisted by the Family Health Strategy (FHS). The selection of participants was performed through probabilistic cluster analysis. The sample size (n = 384) was calculated to include a representative sample of the 52,628 adults registered in the FHS of a countryside city located in the Southeast Region of Brazil. The Morningness-Eveningness Questionnaire (MEQ) was used to determine the chronotype, and Questionnaire-Based Self-Reported Bruxism was used for identifying possible SB and AB. The following clinical and social-behavioral variables were also evaluated: age, sex, BMI, income, physical activity, schooling, alcohol consumption and smoking, chronic diseases and depression. Two logistic regression models were used: one for SB and one for AB. Possible SB was associated with female sex, lack of physical activity and income above 2 minimum wages. Regarding chronotype, a 19% reduction in the chance of possible SB was observed in morning individuals compared to evening individuals (p = .017). Possible AB was associated with younger individuals, smoking and depression. In conclusion, compared with the evening circadian preference, the morning circadian preference was associated with greater protection against possible SB in an adult population assisted by the FHS.

Chronotype in individuals with schizophrenia: A meta-analysis

OBJECTIVE

Emerging evidence shows that evening chronotype is associated with mental health problems, especially mood disorders, but few studies have investigated its association with schizophrenia. Based on meta-analytic methods, we aimed to test whether eveningness is greater in individuals with schizophrenia compared with healthy controls and patients with bipolar I disorder.

METHOD

Medline/Pubmed, Google Scholar, and EBSCO databases were searched up to April 2021 for articles investigating chronotype in individuals with schizophrenia. Two meta-analyses were conducted: individuals with schizophrenia compared with healthy controls and individuals with bipolar I disorder. These meta-analyses were followed by a meta-regression controlling for potential confounders.

RESULTS

Five studies comprising 386 individuals with schizophrenia (age 32.73 years; 67.4% male), 320 with bipolar I disorder (age 31.26 years; 38.3% male) and 638 healthy controls (age 32.19 years; 50.6% male) were included. Participants with schizophrenia were moderately higher on eveningness than healthy controls but they did not differ from those with bipolar I disorder. The difference was not affected by gender, age, and the type of scale used for assessing chronotype.

CONCLUSIONS

Individuals with schizophrenia are more evening oriented than healthy controls and have a similar chronotype to those with bipolar I disorder. The results supported the hypothesis that evening chronotype might be a marker of, or a risk factor for, mental health problems in general and not just limited to affective disorders.

Is chronotype profile a risk indicator for caries in children and adolescents in sub-urban Nigeria?

OBJECTIVES

To determine the association between chronotype and the prevalence of caries among in-school pupils aged 6- to 16-year-old residing in a sub-urban area in Nigeria. We hypothesize that in-school pupils who are evening chronotypes will have significantly higher prevalence of caries than those who are intermediate or morning chronotypes.

METHODS

This secondary analysis of a dataset collected in 2019 from 1502 children aged 6- to 16-year-old attending private and public primary and secondary schools in Ife Central Local Government Area, Nigeria. The dependent variable was caries prevalence. The explanatory variable was participants' chronotype profile (morning, intermediate, and evening). The confounding variables were caries risk factors (socio-economic status, age at last birthday, sex, use of fluoridated toothpaste, frequency of consumption of refined carbohydrates, and oral hygiene status). Poisson regression analysis was conducted.

RESULTS

Data of 1001 (66.6%) students were retrieved. Of these, 59 (5.9%) had caries, 42 (4.2%) were evening type, 526 (52.5%) were intermediate type, and 433 (43.3%) were morning type. There was no significant association between chronotype and the prevalence of caries though children who were intermediate type (APR = 0.83; 95%CI: 0.41-1.66) and morning type (APR = 0.57; 95% CI: 0.27-1.18) were less likely to have caries than were those who were evening type.

CONCLUSION

The children and adolescents' chronotype was not a significant risk indicator for caries in the study population.

Association between Irregular Meal Timing and the Mental Health of Japanese Workers

Breakfast skipping and nighttime snacking have been identified as risk factors for obesity, diabetes, and cardiovascular diseases. However, the effects of irregularity of meal timing on health and daily quality of life are still unclear. In this study, a web-based self-administered questionnaire survey was conducted involving 4490 workers (73.3% males; average age = 47.4 ± 0.1 years) in Japan to investigate the association between meal habits, health, and social relationships. This study identified that irregular meal timing was correlated with higher neuroticism (one of the Big Five personality traits), lower physical activity levels, and higher productivity loss. Irregular meal timing was also associated with a higher incidence of sleep problems and lower subjective health conditions. Among health outcomes, a high correlation of irregular meal timing with mental health factors was observed. This study showed that irregularity of meal timing can be explained by unbalanced diets, frequent breakfast skipping, increased snacking frequency, and insufficient latency from the last meal to sleep onset. Finally, logistic regression analysis was conducted, and a significant contribution of meal timing irregularity to subjective mental health was found under adjustment for other confounding factors. These results suggest that irregular meal timing is a good marker of subjective mental health issues.

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 between Chronotype and Nutritional, Clinical and Sociobehavioral Characteristics of Adults Assisted by a Public Health Care System in Brazil

Chronotype (CT) has been associated with predisposition to chronic noncommunicable diseases (CNCDs), such as diabetes mellitus and obesity. However, the effects of CT on individuals assisted by public health systems (PHSs) in middle-up economies are still poorly explored. The objective of this study was to evaluate the relationship between CT and clinical, sociobehavioral and nutritional aspects in adults assisted by a PHS in Brazil. This is a population-based cross-sectional study. The sample consisted of 380 individuals, selected through probabilistic sampling by clusters, in all health units in a city of approximately 100 thousand inhabitants. Data collection was performed during home visits, by means of general and nutritional interviews, anthropometric measurements and the Morningness-Eveningness Questionnaire (MEQ). Statistical analysis comprised chi-square test and principal component analysis (CPA) followed by Fisher's discriminant analysis to determine aspects associated with each CT (morning, evening or intermediate). With the aim of explaining the variation in the CT scores, the consumption of micronutrients (corrected to the total energy intake) and other individual and sociodemographic variables were used as explanatory factors in the adjustment of a linear regression model. The morning group was characterized by older men, with less than eight years of schooling, with low body mass index (BMI) and with low intake of omega-6, omega-3, sodium, zinc, thiamine, pyridoxine and niacin. The evening group, on the other hand, was composed of younger individuals, with a high consumption of these same nutrients, with high BMI and a higher frequency of heart diseases (p < 0.05). It was concluded that most morning CT individuals were elderly thin males with lower consumption of omega-6 and -3, sodium, zinc, thiamine, pyridoxine and niacin, whereas evening individuals were younger, had higher BMI and had higher consumption of the studied micronutrients. The identification of circadian and behavioral risk groups can help to provide preventive and multidisciplinary health promotion measures.

Later chronotype is associated with unhealthful plant-based diet quality in young Japanese women

BACKGROUND

Having a late chronotype, that is, the tendency to go to sleep and wake up at later hours, influences an individual's physical and mental health. Despite a few studies noting the association of chronotype with healthy dietary patterns, this relationship remains unclear.

PURPOSE

This study aimed to describe the association of chronotype with healthful and unhealthful plant-based diet quality in female Japanese undergraduate students.

DESIGN

Cross-sectional.

PARTICIPANTS AND SETTING

A total of 218 female university students in Tokyo, Japan.

MAIN OUTCOME MEASURES

Healthful and unhealthful plant-based dietary index-Japanese version (hPDI-J and uPDI-J), calculated using the validated brief-type self-administered diet history questionnaire.

STATISTICAL ANALYSES PERFORMED

A five-model stepwise multiple linear regression analysis was conducted. Independent variables were hPDI-J and uPDI-J scores, and dependent variables were various lifestyle habits related to the circadian rhythm and demographic characteristics.

RESULTS

Mean (standard deviation) sleep duration, midpoint of sleep, sleep latency time, and social jetlag were 411 (60) min, 03:56 (00:57), 21 (27) min, and 50 (39) min, respectively. Chronotype and several variables, such as residential status, energy and alcohol intake, and nutritional knowledge, were associated with healthful and unhealthful plant-based diet quality. Individuals who had higher hPDI-J scores were more likely to have an earlier chronotype (β = -0.168, P = 0.019) and better nutritional knowledge (β = 0.164, P = 0.022) than those with lower hPDI-J scores. Individuals were more likely to have higher uPDI-J scores if they were living alone (β = -0.301, P < 0.001), had a later chronotype (β = 0.181, P = 0.001), higher frequency of snacking (β = 0.164, P = 0.019), lower total energy (β = -0.445, P < 0.001), and worse nutritional knowledge (β = -0.172, P = 0.001).

CONCLUSION

This study provided new evidence as to the relationship between sleep and dietary habits, the interaction of which may affect women's health.

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.

Association of the Chronotype Score with Circulating Trimethylamine N-Oxide (TMAO) Concentrations

Individual differences in the chronotype, an attitude that best expresses the individual circadian preference in behavioral and biological rhythms, have been associated with cardiometabolic risk and gut dysbiosis. Up to now, there are no studies evaluating the association between chronotypes and circulating TMAO concentrations, a predictor of cardiometabolic risk and a useful marker of gut dysbiosis. In this study population (147 females and 100 males), subjects with the morning chronotype had the lowest BMI and waist circumference (p < 0.001), and a better metabolic profile compared to the other chronotypes. In addition, the morning chronotype had the highest adherence to the Mediterranean diet (p < 0.001) and the lowest circulating TMAO concentrations (p < 0.001). After adjusting for BMI and adherence to the Mediterranean diet, the correlation between circulating TMAO concentrations and chronotype score was still kept (r = -0.627, p < 0.001). Using a linear regression analysis, higher chronotype scores were mostly associated with lower circulating TMAO concentrations (β = -0.479, t = -12.08, and p < 0.001). Using a restricted cubic spline analysis, we found that a chronotype score ≥59 (p < 0.001, R2 = -0.824) demonstrated a more significant inverse linear relationship with circulating TMAO concentrations compared with knots <59 (neither chronotype) and <41 (evening chronotype). The current study reported the first evidence that higher circulating TMAO concentrations were associated with the evening chronotype that, in turn, is usually linked to an unhealthy lifestyle mostly characterized by low adherence to the MD.

Evening Chronotype Is Associated with Poorer Habitual Diet in US Women, with Dietary Energy Density Mediating a Relation of Chronotype with Cardiovascular Health

BACKGROUND

An innate preference for later timing of sleep and activity, termed evening chronotype, is linked to poorer cardiovascular health (CVH). However, associations of chronotype with specific health behaviors in US women are not well characterized. Of particular interest is habitual diet, because <1% of US adults meet recommendations for a healthful diet.

OBJECTIVES

We aimed to evaluate cross-sectional and prospective associations of chronotype with diet quantity and quality in US women, and to assess whether dietary energy density (ED), a robust predictor of cardiometabolic outcomes, mediates an established chronotype-CVH relation.

METHODS

Data were collected from participants in the AHA Go Red for Women Strategically Focused Research Network cohort (aged 20-76 y; 61% racial/ethnic minority) at baseline (n = 487) and 1-y follow-up (n = 432). Chronotype (evening compared with morning/intermediate) and habitual diet were ascertained from the Morningness-Eveningness Questionnaire and an FFQ, respectively. Multivariable-adjusted linear regression models evaluated cross-sectional and prospective associations of chronotype with diet. Causal mediation analyses assessed whether dietary ED mediated a relation between chronotype and CVH, quantified using AHA Life's Simple 7 score, derived from clinical measurements and validated assessments of CVH components.

RESULTS

Evening compared with morning/intermediate chronotype was associated with poorer diet quality, including lower intakes of plant protein (cross-sectional: β = -0.63 ± 0.24, P < 0.01; prospective: β = -0.62 ± 0.26, P = 0.01), fiber (cross-sectional: β = -2.19 ± 0.65, P < 0.001; prospective: β = -2.39 ± 0.66, P < 0.001), and fruits and vegetables (cross-sectional: β = -1.24 ± 0.33, P < 0.001; prospective: β = -1.15 ± 0.36, P = 0.001). Evening chronotype was also associated with higher dietary ED at baseline (β = 0.20 ± 0.05, P = 0.001) and 1 y (β = 0.19 ± 0.06, P = 0.001). Dietary ED was a partial mediator of the association between evening chronotype and poorer CVH (24.6 ± 9.1%, P < 0.01).

CONCLUSIONS

Evening chronotype could contribute to unhealthful dietary patterns in US women, with higher dietary ED partially mediating the relation between eveningness and poorer CVH. Behavioral interventions to reduce dietary ED might mitigate cardiovascular disease risk in women with evening chronotype.

The relationship between chronotype and sleep behavior during rotating shift work: a field study

Shift work, an essential part of our 24/7 society, inevitably leads to displacement of the habitual sleep period and thereby to misalignment of the internal circadian timing system with the rest-activity cycle and the environment. How interindividual differences in circadian organization affect sleep duration and timing during rotating shift work is not fully understood. The objective of this study was to assess the effect of chronotype, shift type, and their interaction on actigraphy-based sleep behavior in 74 police officers (20 women and 54 men; age [mean ± SD]: 32.1 ± 5.4 years) involved in rotating shift work throughout a 28- to 35-day work cycle consisting of morning, evening, and night shifts. Using linear mixed modeling, we found that chronotype was associated with sleep duration depending on the shift type: increasing morningness was correlated with longer sleep duration during series of consecutive morning shifts, while increasing eveningness was correlated with longer sleep duration during series of evening shifts. During series of night shifts, increasing eveningness was associated with a longer duration of the main sleep episode, but this relationship was attenuated and no longer significant when naps were taken into account due to increased napping in morning chronotypes during series of night shifts. Providing a detailed within-subject characterization of sleep behavior across a complete work cycle consisting of morning, evening, and night shifts, this study advances the understanding of the relationship between chronotype and sleep in rotating shift workers and supports the implementation of work schedules that take into account chronobiological principles.

Association of chronotype as assessed by the midpoint of sleep with the dietary intake and health-related quality of life for elderly Japanese women

The relationship of chronotype differences with dietary habits and health-related outcomes among elderly people is not fully understood, although sex and generation differences are observed in human chronotype. Accordingly, we analysed the association of chronotype (as assessed by the midpoint of sleep) with dietary intake and health-related quality of life (HRQoL) in elderly Japanese women. The subjects in this cross-sectional study were 1618 women aged 65 years and older who were grandmothers or acquaintances of dietetics students. The subjects were classified into quintiles with respect to the midpoint of sleep, from the earliest to the latest quintile. HRQoL was assessed by the Japanese version of the short-form 36-item health survey score. Mental health was assessed by the Center for Epidemiologic Studies Depression (CES-D) Scale. Dietary intake was assessed by a brief-type self-administered diet history questionnaire. A later midpoint of sleep was associated with a lower intake of vitamin D and a higher intake of bread and caffeinated drinks. No correlations were observed between chronotype and other nutrient and food intake. The subjects with a late midpoint of sleep (eveningness) showed poor general health perception (GH) and high CES-D scores. Other HRQoL scores did not differ among groups with different midpoints of sleep. In conclusion, chronotype as assessed by the midpoint of sleep is associated with poor GH and depressive tendencies in elderly Japanese women. Additionally, a few associations were found between dietary intake and chronotype in elderly Japanese women.

Robust stability of melatonin circadian phase, sleep metrics, and chronotype across months in young adults living in real-world settings

Appropriate synchronization of the timing of behaviors with the circadian clock and adequate sleep are both important for almost every physiological process. The timing of the circadian clock relative to social (ie, local) clock time and the timing of sleep can vary greatly among individuals. Whether the timing of these processes is stable within an individual is not well-understood. We examined the stability of circadian-controlled melatonin timing, sleep timing, and their interaction across ~ 100 days in 15 students at a single university. At three time points ~ 35-days apart, circadian timing was determined from the dim-light melatonin onset (DLMO). Sleep behaviors (timing and duration) and chronotype (ie, mid-sleep time on free days corrected for sleep loss on school/work days) were determined via actigraphy and analyzed in ~ 1-month bins. Melatonin timing was stable, with an almost perfect relationship strength as determined via intraclass correlation coefficients ([ICC]=0.85); average DLMO timing across all participants only changed from the first month by 21 minutes in month 2 and 5 minutes in month 3. Sleep behaviors also demonstrated high stability, with ICC relationship strengths ranging from substantial to almost perfect (ICCs = 0.65-0.85). Average DLMO was significantly associated with average chronotype (r²  = 0.53, P <.01), with chronotype displaying substantial stability across months (ICC = 0.61). These findings of a robust stability in melatonin timing and sleep behaviors in young adults living in real-world settings holds promise for a better understanding of the reliability of previous cross-sectional reports and for the future individualized strategies to combat circadian-associated disease and impaired safety (ie, "chronomedicine").

Sleep and Metabolic Syndrome

Metabolic syndrome (MetS) refers to the clustering of risk factors for cardiovascular disease and diabetes, including central adiposity, hypertension, dyslipidemia, and hyperglycemia. During the past 20 years, there have been parallel and epidemic increases in MetS and impaired sleep. This article describes evidence on the association between MetS and short sleep duration, circadian misalignment, insomnia, and sleep apnea. Potential mechanisms where impaired sleep desynchronizes and worsens metabolic control and interventions to improve sleep and potentially improve MetS are presented.

Association of Time-of-Day Energy Intake Patterns with Nutrient Intakes, Diet Quality, and Insulin Resistance

Evidence shows time-of-day of energy intake are associated with health outcomes; however, studies of time-of-day energy patterns and their health implication are still lacking in the Asian population. This study aims to examine the time-of-day energy intake pattern of Chinese adults and to examine its associations with nutrient intakes, diet quality, and insulin resistance. Dietary data from three 24-h recalls collected during the 2015 China Health and Nutrition Survey (CHNS) were analyzed (n = 8726, aged ≥ 18 years). Time-of-day energy intake patterns were determined by latent class analysis (LCA). General Linear Models and Multilevel Mixed-effects Logistic Regression Models were applied to investigate the associations between latent time-of-day energy intake patterns, energy-adjusted nutrient intakes, diet quality score, and insulin resistance. Three time-of-day energy intake patterns were identified. Participants in the “Evening dominant pattern” were younger, had higher proportions of alcohol drinkers and current smokers. The “Evening dominant pattern” was associated with higher daily energy intake and a higher percentage of energy from fat (%) (p < 0.001), as well as higher insulin resistance risk (OR = 1.21; 95% CI: 1.05, 1.40), after adjusting for multivariate covariates. The highest diet quality score was observed in participants with “Noon dominant pattern” (p < 0.001). A higher proportion of energy in the later of the day was associated with insulin resistance in free-living individuals.

A Low-Carbohydrate Ketogenic Diet and Treadmill Training Enhanced Fatty Acid Oxidation Capacity but Did Not Enhance Maximal Exercise Capacity in Mice

The low-carbohydrate ketogenic diet (LCKD) is a dietary approach characterized by the intake of high amounts of fat, a balanced amount of protein, and low carbohydrates, which is insufficient for metabolic demands. Previous studies have shown that an LCKD alone may contribute to fatty acid oxidation capacity, along with endurance. In the present study, we combined a 10-week LCKD with an 8-week forced treadmill running program to determine whether training in conjunction with LCKD enhanced fatty acid oxidation capacity, as well as whether the maximal exercise capacity would be affected by an LCKD or training in a mice model. We found that the lipid pool and fatty acid oxidation capacity were both enhanced following the 10-week LCKD. Further, key fatty acid oxidation related genes were upregulated. In contrast, the 8-week training regimen had no effect on fatty acid and ketone body oxidation. Key genes involved in carbohydrate utilization were downregulated in the LCKD groups. However, the improved fatty acid oxidation capacity did not translate into an enhanced maximal exercise capacity. In summary, while favoring the fatty acid oxidation system, an LCKD, alone or combined with training, had no beneficial effects in our intensive exercise-evaluation model. Therefore, an LCKD may be promising to improve endurance in low- to moderate-intensity exercise, and may not be an optimal choice for those partaking in high-intensity exercise.

Higher eating frequency is associated with lower adiposity and robust circadian rhythms: a cross-sectional study

BACKGROUND

Although overweight and obesity are assumed to arise from an energy imbalance, evidence has shown that the frequency and timing of meals are also potential risk factors for obesity. However, the lack of a consistent approach to define eating patterns relative to internal circadian rhythms limits the extent of these findings.

OBJECTIVES

The objective of this study was to investigate the association of the circadian pattern of energy intake with adiposity and with internal circadian rhythms.

METHODS

A total of 260 Spanish adults (aged 20-30 y; 78.1% women) were included in a 6-d cross-sectional study. Participants documented sleep and dietary intake within the study period. From these data, we evaluated the chronotype, eating patterns (meal timing, eating duration, and eating frequency), and we obtained the daily profile of energy intake. In addition, we evaluated the circadian pattern of wrist temperature (internal circadian rhythm marker). Circadian patterns of energy intake and wrist temperature were analyzed, and their association among them and with anthropometric variables and diet quality was studied.

RESULTS

The greater fragmentation of the circadian pattern of energy intake was associated with lower BMI (in kg/m2; -10.55; 95% CI: -16.96, -4.13; P = 0.001). In addition, a greater eating frequency (≥5 eating occasions/d) was significantly associated with lower BMI (-1.88; 95% CI: -3.27, -0.48) and higher energy intake after 20:00 (4.14% of kcal; 95% CI: 1.67, 7.16). Furthermore, a greater eating frequency was associated with lower fragmentation (P = 0.042) and greater stability of the circadian pattern of wrist temperature (P = 0.016).

CONCLUSIONS

The daily pattern of energy intake is associated with adiposity and robust circadian rhythms. Our results shed light on the relevance of eating frequency as a potential zeitgeber for the circadian system. Although more evidence is needed, eating frequency could be considered for future chrono-nutritional recommendations for the prevention of circadian misalignment and obesity.

Social Jetlag and Prostate Cancer Incidence in Alberta's Tomorrow Project: A Prospective Cohort Study

Simple Summary

Due to social obligations (e.g., school, work), people shift their sleep and activity time regardless of their sleep-wake preference. To compensate for the lack of sleep accumulated over the workdays, people tend to oversleep on a work-free day. This difference in sleep timing between workdays and free days resembles traveling across different time zones, which causes jetlag (a mild form of circadian disruption). Thus, it is named social jetlag. Social jetlag has been linked with obesity, metabolic disorders, and cardiovascular risk in previous research. This study assessed social jetlag in 7455 cancer-free men in Alberta’s Tomorrow Project and followed them for on average 9.6 years, 250 men were diagnosed with prostate cancer. The study found that the more social jetlag men experienced, the greater their prostate cancer risk was. This finding warrants future research to better understand the complex behavioral and biological pathways between social jetlag and prostate cancer risk.

Abstract

We investigated the association of social jetlag (misalignment between the internal clock and socially required timing of activities) and prostate cancer incidence in a prospective cohort in Alberta, Canada. Data were collected from 7455 cancer-free men aged 35–69 years enrolled in Alberta’s Tomorrow Project (ATP) from 2001–2007. In the 2008 survey, participants reported usual bed- and wake-times on weekdays and weekend days. Social jetlag was defined as the absolute difference in waking time between weekday and weekend days, and was categorized into three groups: 0–<1 h (from 0 to anything smaller than 1), 1–<2 h (from 1 to anything smaller than 2), and 2+ h. ATP facilitated data linkage with the Alberta Cancer Registry in June 2018 to determine incident prostate cancer cases (n = 250). Hazard ratios (HR) were estimated using Cox proportional hazards regressions, adjusting for a range of covariates. Median follow-up was 9.57 years, yielding 68,499 person-years. Baseline presence of social jetlag of 1–<2 h (HR = 1.52, 95% CI: 1.10 to 2.01), and 2+ hours (HR = 1.69, 95% CI: 1.15 to 2.46) were associated with increased prostate cancer risk vs. those reporting no social jetlag (p for trend = 0.004). These associations remained after adjusting for sleep duration (p for trend = 0.006). With respect to chronotype, the association between social jetlag and prostate cancer risk remained significant in men with early chronotypes (p for trend = 0.003) but attenuated to null in men with intermediate (p for trend = 0.150) or late chronotype (p for trend = 0.381). Our findings suggest that greater than one hour of habitual social jetlag is associated with an increased risk of prostate cancer. Longitudinal studies with repeated measures of social jetlag and large samples with sufficient advanced prostate cancer cases are needed to confirm these findings.

Depression and anxiety symptoms correlate with diurnal preference, sleep habits, and Per3 VNTR polymorphism (rs57875989) in a non-clinical sample

BACKGROUND

Evidences suggest that alterations in circadian rhythms trigger the development of mental disorders. Eveningness, sleep behavior, and circadian genes polymorphisms have been associated with depression and anxiety symptomatology. However, the mechanism underlying these interactions is not well understood. We investigated the contribution of diurnal preference, sleep habits, and PER3 VNTR polymorphism (rs57875989) to depression and anxiety symptoms in a Northeast sample from the Brazilian population.

METHODS

Eight hundred and four young adults completed the Morningness-Eveningness (MEQ), Munich Chronotype (MCTQ), Center for Epidemiologic Studies - Depression (CES-D), and Beck Anxiety Inventory (BAI) questionnaires. All participants were genotyped and linear regression was performed to test the interactions between the genetic /behavioral variants and depression/ anxiety symptoms.

RESULTS

Eveningness and sleep behaviors (bedtime, wake-up time, sleep duration, and midpoint of sleep) were correlated with depression symptomatology, specifically in somatic factors of the CES-D questionnaire. No correlation was found between diurnal preference/sleep habits with anxiety symptoms for both BAI total score and its factors. However, women with PER3^4/4 genotype showed less interpesonal affect in depression symptomatology and more anxiety symptoms in four factors of the BAI questionnaire.

LIMITATIONS

Mainly because this study was based on self-report questionnaires and was limited to undergraduate students aging 18 to 30 years old.

CONCLUSION

These results reinforce a role for sleep and diurnal preference in depression, and PER3 VNTR polymorphism in anxiety symptomatology, particularly in women.

The circadian machinery links metabolic disorders and depression: A review of pathways, proteins and potential pharmacological interventions

Circadian rhythms are responsible for regulating a number of physiological processes. The central oscillator is located within the suprachiasmatic nucleus (SCN) of the hypothalamus and the SCN synchronises the circadian clocks that are found in our peripheral organs through neural and humoral signalling. At the molecular level, biological clocks consist of transcription-translation feedback loops (TTFLs) and these pathways are influenced by transcription factors, post-translational modifications, signalling pathways and epigenetic modifiers. When disruptions occur in the circadian machinery, the activities of the proteins implicated in this network and the expression of core clock or clock-controlled genes (CCGs) can be altered. Circadian misalignment can also arise when there is desychronisation between our internal clocks and environmental stimuli. There is evidence in the literature demonstrating that disturbances in the circadian rhythm contribute to the pathophysiology of several diseases and disorders. This includes the metabolic syndrome and recently, it has been suggested that the 'circadian syndrome' may be a more appropriate term to use to not only describe the cardio-metabolic risk factors but also the associated comorbidities. Here we overview the molecular architecture of circadian clocks in mammals and provide insight into the effects of shift work, exposure to artificial light, food intake and stress on the circadian rhythm. The relationship between circadian rhythms, metabolic disorders and depression is reviewed and this is a topic that requires further investigation. We also describe how particular proteins involved in the TTFLs can be potentially modulated by small molecules, including pharmacological interventions and dietary compounds.

Eating habits, sleep, and a proxy for circadian disruption are correlated with dyslipidemia in overweight night workers

OBJECTIVE

The aim of this study was to evaluate the relationship between proxy for circadian disruption, eating habits, sleep characteristics, and dyslipidemic parameters.

METHODS

This was a randomized, double-blind, crossover controlled clinical trial, and for this study, only baseline data were used. The sample was composed of 36 overweight female nurses who worked on a fixed night shift (12 × 36 h). Linear regression models were used to assess the relationship between the mentioned variables.

RESULTS

The participants' average age was 39.4 y (Standard error (SE) 1 y) and the average nighttime sleep duration was 5.76 h (SE 0.16 h). The average chronotype indicated a moderate early type (03:03 h; SE 20 min) and the average social jetlag was 03:42 h (SE 10 min). It was found that 1 h less of nighttime sleep increased very-low-density lipoprotein cholesterol levels by 2.75 mg/dL and triacylglyceride levels by 3.62 mg/dL. Additionally, higher social jetlag was associated with higher low-density lipoprotein cholesterol levels. On the other hand, each additional hour in the chronotype increased high-density lipoprotein cholesterol levels by 3.06 mg/dL and a time interval >2 h between the last meal and sleep onset was associated with higher high-density lipoprotein cholesterol levels.

CONCLUSION

Short duration of nighttime sleep and high social jetlag are risk factors for dyslipidemia, whereas the late type and the longer time interval between the last meal and sleep onset appear to be protective factors for dyslipidemia.

Morning diurnal preference and food intake: a Mendelian randomization study

BACKGROUND

Poor dietary choices may underlie known associations between having an evening diurnal preference and cardiometabolic diseases. Assessing causal links between diurnal preference and food intake is now possible in Mendelian randomization (MR) analyses.

OBJECTIVES

We aimed to use a 2-sample MR to determine potential causal effects of genetic liability to a morning preference on food intake. We also examined potential causal effects of a morning preference on objectively captured response performances to email-administered 24-h diet recalls.

METHODS

We used genetic variants associated with a morning preference from a published genome-wide association meta-analysis. Our outcomes included 61 food items with estimates from a food-frequency questionnaire in the UK Biobank (n = 361,194). For significant findings, we repeated the analysis using intake estimates from modified 24-h diet recalls in a subset of overlapping participants (n = 146,086). In addition, we examined 7 response performance outcomes, including the time and duration of responses to 24-h diet recalls (n = 123,035). MR effects were estimated using an inverse-variance weighted analysis.

RESULTS

Genetic liability to a morning preference was associated with increased intake of 6 food items (fresh fruit, alcohol with meals, bran cereal, cereals, dried fruit, and water), decreased intake of 4 food items (beer plus cider, processed meat, other cereals [e.g., corn or frosted flakes], and full cream milk), increased temperature of hot drinks, and decreased variation in diet (PFalse Discovery Rate < 0.05). There was no evidence for an effect on coffee or tea intake. Findings for fresh fruit, beer plus cider, bran cereal, and cereal were consistent when intakes were estimated by 24-h diet recalls (P < 0.05). We also identified potential causal links between a morning preference with earlier timing and a shorter duration for completing email-administered 24-h diet recalls.

CONCLUSIONS

Our findings provide evidence for a potentially causal effect of a morning preference with the increased intake of foods known to constitute a healthy diet, suggesting possible health benefits of adopting a more morning diurnal preference.