Is time of eating associated with BMI and obesity? A population-based study.

PURPOSE: Time-related eating patterns have been associated with metabolic and nutritional diseases such as obesity. However, there is a lack of representative studies on this subject. This study's aim was to assess the association between the timing of eating and obesity in a large and representative sample of the Brazilian adult population (POF 2008-2009 survey). METHODS: Two days of adults' food diary (n = 21,020) were used to estimate tertiles of first and last meal intake times, eating midpoint, caloric midpoint time, and calories consumed from 18:00 h onwards. BMI was estimated and its values, as well as excess weight (BMI ≥ 25 kg/m2) and obesity (BMI ≥ 30 kg/m2) were used as outcomes. Multiple linear and logistic regressions were performed. RESULTS: The first (ß = 0.65, 95% CI 0.37-0.93) and last food intake time (ß = 0.40, 95% CI 0.14-0.66), eating midpoint (ß = 0.61, 95% CI 0.34-0.88) and calories consumed after 21:00 h (ß = 0.74, 95% CI 0.32-1.16) and 22:00 h (ß = 0.75, 95% CI 0.18-1.32) were positively associated with BMI. The likelihood of having excess weight or obesity was significantly higher in the third tertile of the first food intake time (OR = 1.28, 95% CI 1.13-1.45 and OR = 1.34, 95% CI 1.13-1.58, respectively), last food intake time (OR = 1.16, 95% CI 1.03-1.32; and OR = 1.18, 95% CI 1.00-1.41, respectively), eating midpoint (OR = 1.28, 95% CI 1.13-1.45; and OR = 1.35, 95% CI 1.14-1.59, respectively) and energy consumption after 21:00 h (OR = 1.33, 95% CI 1.10-1.59). CONCLUSION: Chrononutrition meal patterns indicative of late meal intake were significantly associated with high BMI, excess weight and obesity in the Brazilian population.

Exogenous melatonin decreases circadian misalignment and body weight among early types.

Shift workers experience chronic circadian misalignment, which can manifest itself in reduced melatonin production, and has been associated with metabolic disorders. In addition, chronotype modulates the effect of night shift work, with early types presenting greater circadian misalignment when working night shift as compared to late types. Melatonin supplementation has shown positive results reducing weight gain in animal models, but the effect of exogenous melatonin in humans on body weight in the context of shift work remains inconsistent. The aim of this study was thus to evaluate the effects of exogenous melatonin on circadian misalignment and body weight among overweight night shift workers, according to chronotype, under real-life conditions. We conducted a double-blind, randomized, placebo-controlled, crossover trial where melatonin (3 mg) or placebo was administered on non-night shift nights for 12 weeks in 27 female nurses (37.1 yo, ±5.9 yo; BMI 29.9 kg/m2 , ±3.3 kg/m2 ). Melatonin (or placebo) was only taken on nights when the participants did not work night shifts, that is, on nights when they slept (between night shifts and on days off). Composite Phase Deviations (CPD) of actigraphy-based mid-sleep timing were calculated to measure circadian misalignment. The analyses were performed for the whole group and by chronotype. We found approximately 20% reduction in circadian misalignment after exogenous melatonin administration considering all chronotypes. Moreover, melatonin supplementation in those who presented high circadian misalignment, as observed in early chronotypes, reduced body weight, BMI, waist circumference, and hip circumference, without any change in the participants' calorie intake or physical activity levels.

Late evening electric light exposure is associated with low sleep regularity in adolescents living in rural areas.

In this study, we tested the prediction that sleep regularity would be lower in adolescents exposed to late evening electric light (LEEL) than in those without exposure to it. The Sleep Regularity Index was calculated based on actigraph recordings from adolescents living in rural communities in Argentina and Brazil that were either exposed to LEEL or not. The effect of the LEEL on sleep variables was tested using linear models considering sex and age, as well as accounting for the differences between countries. Sleep onset was delayed, sleep duration shortened, and Sleep Regularity Index was 4 [1-8] points lower in the group exposed to LEEL (p = .0176, eta2 =0.13). Our results show that beyond sleep phase and duration, which are known to be affected by LEEL in this age group, sleep irregularity should also be considered as an important outcome variable when assessing the adverse effects of evening light on adolescents.

Association Between Augmentation Index and Total Sleep Time in Night Shift Workers.

Augmentation index and pulse wave velocity are markers of vascular compromise and independent predictors of cardiovascular risk and mortality. While the link between shift work and heightened cardiovascular risk is established, the intricate genesis of early cardiovascular outcomes in shift workers remains incompletely understood. However, there is evidence that sleep duration plays a role in this regard. Here we evaluate the association of total sleep time with pulse wave velocity, augmentation index, and central blood pressure in night shift workers. This study cross-sectionally evaluated the association of total sleep time evaluated by 10-day monitoring actigraphy with augmentation index, pulse wave velocity, and brachial and central blood pressure evaluated by oscillometry in nursing professionals, 63 shift workers (89% women; age = 45.0 ± 10.5 years), and 17 (100% women; age = 41.8 ± 15.6) day workers. There were no differences in the studied variables between shift workers and day workers. Results of correlation analysis demonstrated that pulse wave velocity, central systolic blood pressure, central diastolic blood pressure, brachial systolic blood pressure, and brachial diastolic blood pressure tended to have significant correlation with each other, while these measures did not have a significant relationship with augmentation index in both groups. However, results of adjusted restricted cubic spline analysis showed a U-shaped-curve association between total sleep time and augmentation index (p < 0.001 for trend) with a nadir at 300-360 min of total sleep time in shift workers. The present study showed that total sleep time, assessed by actigraphy, had a U-shaped association with augmentation index in shift workers, which indicated better characteristics of vascular functionality when sleep time was 5-6 h in the workers studied.

Night Shift Work and Sleep Disturbances in Women: A Scoping Review.

This scoping review aimed to synthesize evidence on sleep disturbances in female shift workers. The update Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews was used. Twelve studies were included, four of which used actigraphy to assess sleep duration, efficiency, and latency. Seven studies evaluated the quality of sleep and three verified the sleepiness of women. This review adds to the body of evidence as the findings are homogeneous and allow a robust conclusion, suggesting that night shift work may be a potential factor for adverse effects on sleep of female shift workers.

Shift Work and Early Arterial Stiffness: A Systematic Review.

Shift work is a way of organizing rotating schedules throughout the day. This can include 1-3 shifts for the same person on a rotational basis with other workers. Schedules that include night work have been associated with cardiovascular risk, mainly due to circadian misalignment. This systematic review sought to determine whether shift work is a risk factor for increased arterial stiffness. A systematic review of different databases was performed, using the following keywords: work shift, night work, arteriosclerosis, vascular stiffness, arterial stiffness, pulse wave velocity, and their Medical Subject Headings. We selected and analyzed 11 articles regarding pulse wave velocity as an indicator of arterial stiffness. Two studies identified higher levels of arterial stiffness in shift workers compared to day workers, while two studies found the opposite. In addition, four studies found no differences in arterial stiffness between shifts, two studies associated shorter sleep duration with arterial stiffness, and one study observed that physical activity could prevent adverse cardiovascular outcomes in shift workers. The findings are heterogeneous and preclude any robust conclusions. However, the present review points to the need for further studies to investigate arterial stiffness in shift workers, with greater control for confounding factors and longitudinal design.

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.

Insomnia episodes, new-onset pharmacological treatments, and other sleep disturbances during the COVID-19 pandemic: a nationwide cross-sectional study in Brazilian health care professionals.

STUDY OBJECTIVES: To evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic on insomnia and other sleep disturbances in health care professionals. METHODS: A survey was distributed using social media and organizational emails to Brazilian active health care professionals during the COVID-19 outbreak. We explored potential associated factors including age, sex, occupation, workplace, work hours, income, previous infection with COVID-19, recent/current contact with COVID-19 patients, regional number of incident deaths, anxiety, and burnout. We evaluated new-onset/previous insomnia worsening episodes (primary outcome), new pharmacological treatments, sleep quality, duration, nightmares, and snoring (secondary outcomes). RESULTS: A total of 4,384 health professionals from all regions of the country were included in the analysis (44 ± 12 years, 76% females, 53.8% physicians). Overall, 55.7% were assisting patients with COVID-19, and 9.2% had a previous COVID-19 infection. The primary outcome occurred in 32.9% of respondents in parallel to 13% new pharmacological treatments for insomnia. The sleep quality worsened for 61.4%, while 43.5% and 22.8% reported ≥ 1-hour sleep duration reduction and worsening or new-onset nightmares, respectively. Multivariate analyses showed that age (odds ratio [OR]: 1.008; 95% confidence interval [CI] 1.001-1.015), females (OR: 1.590; 95% CI 1.335-1.900), weight change (decrease: OR: 1.772; 95% CI 1.453-2.161; increase: OR: 1.468; 95% CI 1.249-1.728), prevalent anxiety (OR: 3.414; 95% CI 2.954-3.948), new-onset burnout (OR: 1.761; 95% CI 1.489-2.083), family income reduction > 30% (OR: 1.288; 95% CI 1.069-1.553), and assisting patients with COVID-19 (OR: 1.275; 95% CI 1.081-1.506) were independently associated with new-onset or worsening of previous insomnia episodes. CONCLUSIONS: We observed a huge burden of insomnia episodes and other sleep disturbances in health care professionals during the COVID-19 pandemic. CITATION: Drager LF, Pachito DV, Moreno CRC, et al. Insomnia episodes, new-onset pharmacological treatments, and other sleep disturbances during the COVID-19 pandemic: a nationwide cross-sectional study in Brazilian health care professionals. J Clin Sleep Med. 2022;18(2):373-382.

Are We Ready to Implement Circadian Hygiene Interventions and Programs?

Circadian hygiene, a concept not to be confused with the notion of public or social hygiene, should be discussed among experts and society. Light-dark cycles and other possible synchronizers of the human circadian timing system affect ways of life, including sleeping, eating, working and physical activity. Some of these behaviors have also been investigated individually as synchronizers (e.g., eating times). Therefore, the knowledge held today about circadian rhythms, and their implications for health, allows future perspectives in this field to be mapped. The present article summarizes the latest knowledge on factors influencing circadian rhythms to discuss a perspective for the future of health promotion based on circadian hygiene. However, it is important to highlight that circadian hygiene is the product of an imbrication of individual and societal involvement. First, it is important to adopt practices and devise public health policies in line with circadian hygiene. Second, individual healthy habits require internal rhythms to be examined. Last, the research agenda on circadian hygiene can be developed on a public as well as individual level, raising the question as to how much society is willing to embrace this change.

Timing and Composition of Last Meal before Bedtime Affect Sleep Parameters of Night Workers.

Night workers tend to eat irregularly, both in terms of meal times and composition. The disruption in energy metabolism caused by inappropriate eating habits can negatively affect the sleep quality of these individuals. The objectives of this study were to determine the interval between the last meal and bedtime and its relationship with both diurnal and nocturnal sleep parameters, as well as to evaluate the association of the adequacy of this meal with sleep parameters. The analyses were carried out for a usual sleep routine on a workday and a day off. This cross-sectional study was part of a controlled, randomized, double-blind, crossover clinical trial. The sample comprised 30 female nursing professionals who worked permanent night shifts of 12 × 36 h. Timing and composition of the last meal were obtained from food diaries, and sleep parameters were collected via actigraphy. On multiple linear regression analysis, every hour decrease in the interval between the last meal and sleep onset there was an increase of 0.39 h on diurnal sleep duration. Regarding food intake, every 1 g of fat and 1 g of carbohydrate consumed was associated with an increase in diurnal sleep onset latency of 0.13 h and 0.02 h, respectively. These findings suggest that both timing and composition of the last meal before bedtime may be potential key factors for good diurnal and nocturnal sleep among night-shift workers.

A Nutritional Counseling Program Prevents an Increase in Workers' Dietary Intake and Body Weight During the COVID-19 Pandemic.

The COVID-19 pandemic caused thousands of deaths and changed lives all over the world. Daily life has also altered people's eating habits, mainly among those who stayed working at home. However, changes in the eating habits of workers who remained working during the pandemic are still unknown. The aim of this study was to evaluate the impact of the COVID-19 pandemic on the dietary habits of day and shift workers from a condominium management company, as well as to measure adherence to a nutritional counseling program and its effect on workers' food intake and body weight. One hundred and fifty-one workers (77.5% of day workers and 22.5% of shift workers) were followed up in the pre-pandemic period and during the pandemic. Data on anthropometry, food consumption, and adherence to nutritional counseling were collected during nutritional meetings, which focused on qualitative modification of food intake and control of energy consumption. The rate of adherence to the program did not differ between shifts. The pandemic significantly increased the intake of calories, macronutrients, and several micronutrients in workers of both shifts. Adherence to the nutritional counseling program had an impact on the consumption of proteins and some micronutrients, and also promoted a reduction in body weight and body mass index of workers of both shifts. Evening/night shift workers overall ate their meals later than day workers and also presented an earlier afternoon snack during the pandemic when compared with the pre-pandemic period. In conclusion, the pandemic seems to contribute to the increase in food intake of workers, regardless of the work shift. Those who joined a nutritional counseling program managed their food intake and lost weight.

COVID-19 pandemic impact on sleep habits, chronotype, and health-related quality of life among high school students: a longitudinal study.

STUDY OBJECTIVES: The COVID-19 pandemic has challenged the population of affected areas in multiple dimensions. Adolescents have been especially affected with school closure and home confinement. The impact of the pandemic on sleep habits and quality of sleep and quality of life among adolescents has not been adequately characterized. We hypothesized that the COVID-19 pandemic has induced an evening shift of the daily rhythm among adolescents and adversely affected sleep quality and quality of life of high school students. METHODS: Students were questioned about their usual bed and wake-up times and answered the Pittsburgh Sleep Quality Index Questionnaire, the Epworth Sleepiness Scale, the Horne-Osteberg Morningness-Eveningness Questionnaire, and the World Health Organization Quality of Life Questionnaire-abbreviated version before and during the pandemic. RESULTS: Ninety-four students (64% females, aged 15 ± 1 years) participated in both phases of the study. Students delayed bed and wake-up times by 1.5 (0.5-2.0) and 2.0 (1.5-2.5) hours, respectively. Chronotype (per the Morningness-Eveningness Questionnaire) shifted toward eveningness during the pandemic. Sleep duration increased and quality of sleep (per the Pittsburgh Sleep Quality Index) improved only among those students with shorter sleep duration before the pandemic. During the pandemic, the physical and psychological domains of the World Health Organization Quality of Life Questionnaire worsened but the environmental domain improved as compared with the study before the pandemic. CONCLUSIONS: High school students have delayed bed and wake-up times and shifted chronotype toward eveningness during the COVID-19 pandemic. The worsening of the physical and psychological World Health Organization Quality of Life Questionnaire domains and improvement in the environmental domain highlight the conflicting experiences that high school students are facing during the COVID-19 pandemic.

The effect of urbanization on sleep, sleep/wake routine, and metabolic health of residents in the Amazon region of Brazil.

Studying communities with different levels of urbanization may further the understanding of risk factors underlying metabolic diseases. The present study is unique by comprising detailed assessment of sleep and activity, biological rhythms, and metabolic factors of men from the same geographical location and place of birth that reside in different, rural vs. town, stages of urbanization. Sleep patterns, activity, and metabolic indicators in two groups (rural, n = 22 and town/urban, n = 20) of men residing in an Amazonian community (Xapuri, Acre, Brazil) were compared. Sociodemographic, anthropometric, and metabolic variables - fasting glucose, insulin resistance, triglycerides, total HDL cholesterol, LDL cholesterol, and VLDL cholesterol - were assessed. Sleep patterns, light exposure, and physical activity levels were additionally assessed by actigraphy, plus daily activities were recorded in diaries for 10 days. Town/urban dwellers were found to have significantly higher body weight, fasting glucose, insulin levels, and insulin resistance than rural dwellers, whereas triglycerides levels were similar. Town/Urban dwellers had shorter sleep duration (p < .01) and later sleep onset and offset times (p = .01). Our findings show an association between stage of urbanization and presence of risk factors for metabolic disorders, such as overweight, insulin resistance, increased glucose levels, short sleep duration, and less natural light exposure during work times.

Eating Behavior (Duration, Content, and Timing) Among Workers Living under Different Levels of Urbanization.

Urbanization has contributed to extended wakefulness, which may in turn be associated with eating over a longer period. Here, we present a field study conducted in four groups with different work hours and places of living in order to investigate eating behavior (duration, content, and timing). Anthropometric measures were taken from the participants (rural (n = 22); town (n = 19); city-day workers (n = 11); city-night workers (n = 14)). In addition, a sociodemographic questionnaire was self-answered and 24-h food recalls were applied for three days. The 24-h food recalls revealed that fat intake varied according to the groups, with the highest consumption by the city-day workers. By contrast, city-day workers had the lowest intake of carbohydrate, whereas the rural group had the highest. In general, all groups had some degree of inadequacy in food consumption. Eating duration was negatively correlated with total energy intake, fat, and protein consumption in the rural and town groups. There was a positive correlation between body mass index and eating duration in both city groups. The rural group had the earliest start time of eating, and this was associated with a lower body mass index. This study suggested that food content and timing, as well as eating duration, differed according to place of living, which in turn may be linked to lifestyle.

Prudent diet is associated with low sleepiness among short-haul truck drivers.

OBJECTIVES: The lifestyle of postindustrial society has undergone major shifts characterized by changes in demographic and epidemiologic profiles, eating habits, and job structures, with irregular working hours, particularly night shifts. The investigation of dietary patterns is of great importance for the discussion and devising of effective dietary strategies for shift and night workers in general, particularly in view of the increased sleepiness reported during night work. OBJECTIVE: We aimed to determine the association between dietary patterns of Brazilian truck drivers and sleepiness levels, according to work shift. METHODS: A cross-sectional study of 52 drivers (25 long haul and 27 short haul) at a freight company was carried out. This study entailed application of a structured questionnaire collecting sociodemographic, lifestyle, and nutritional status data. Assessment of dietary intake using a 24-h dietary recall and an evaluation of sleepiness by the Karolinska Sleepiness Scale were performed. The principal components of the diet were analyzed by factor analysis to derive dietary patterns. A linear mixed model was then applied to determine a model for sleepiness levels of the drivers as a function of dietary pattern, time of day, and work shift. RESULTS: Three intake patterns were derived: traditional, prudent, and Western. Associations of time of day (F = 23.629, P < 0.01) and shift type (F = 42.218, P < 0.01) on sleepiness were found. An association between diet and sleepiness was also evident, where the prudent pattern was associated with low sleepiness among short-haul truck drivers (F = 3.865, P = 0.02). CONCLUSIONS: The results of the present study revealed an association between dietary patterns and short-haul driving, in which the healthy pattern produced low sleepiness during the day. The sleepiness curve of long-haul drivers appears to have a flattening pattern, probably because of irregular working times.

Working Time Society consensus statements: Evidence-based effects of shift work on physical and mental health.

Potential effects of shift work on health are probably related to the misalignment between the light-dark cycle and the human activity-rest cycle. Light exposure at night mediates these effects, including social misalignment and leads to an inversion of activity and rest, which, in turn, is linked to changes in behaviours. This article reviews the epidemiological evidence on the association between shift work and health, and possible mechanisms underlying this association. First, evidence from findings of the meta-analyses and systematic reviews published in the last 10 yr is presented. In addition, it reports the larger single-occupation studies and recent large population-based studies of the general workforce. Koch's postulates were used to evaluate the evidence related to the development of disease as a result of exposure to shift work. Finally, we discussed limitations of the multiple pathways that link shift work with specific disorders and the methodological challenges facing shift work research. We concluded that the clearest indications of shift work being the cause of a disease are given when there is a substantial body of evidence from high quality field studies showing an association and there is good evidence from laboratory studies supporting a causal explanation of the link.

A 2-year follow-up study of work ability among college educators.

The aim of this study was to evaluate work ability among college educators before and after an intervention at the workplace. An administrative restructuring in the workplace started to be implemented in 2005. The work ability index (WAI) was administered to 154 educators before the restructure in 2004 and to 60 educators following the restructure in 2006. A t-test comparing the WAI score of the 60 educators who took part in both phases showed a trend of improving work ability (p=0.06; mean WAI in 2004 was 41.7 and 43.3 in 2006). The results suggest that the intervention led to an improvement in psychosocial factors, which in turn positively influenced work ability.

Musculoskeletal pain and insomnia among workers with different occupations and working hours.

Several studies have shown a bidirectional relationship between insomnia and pain. The aim of this study was to evaluate whether working hours and type of occupation are associated with insomnia, pain and insomnia plus pain. Insomnia and musculoskeletal pain symptoms were measured in airline pilots, rural workers and factory workers using validated indexes. Rural and night work were predictors for the outcomes (insomnia and pain). However, musculoskeletal pain was found to be a predictor of insomnia but not vice versa. The current findings suggest that working hours and type of occupation play a role in the sleep-pain relationship.

Irregular working times and metabolic disorders among truck drivers: a review.

A number of studies to better understand the complex physiological mechanism involved in regulating body weight have been conducted. More specifically, the hormones related to appetite, leptin and ghrelin, and their association to obesity have been a focus of investigation. Circadian patterns of these hormones are a new target of research. The behaviour of these hormones in individuals subject to atypical working times such as shiftwork remains unclear. Shiftwork is characterized by changes in biological rhythms and cumulative circadian phase changes, being associated with high rates of obesity and metabolic syndrome. Truck drivers, who work irregular shifts, frequently present a high prevalence of obesity, which might be associated with work-related factors and/or lifestyle. In this context, the aim of this paper was to discuss the relationship of body mass index, appetite-related hormones and sleep characteristics in truck drivers who work irregular shifts compared with day workers.