| 1. |
|
|
| 2. |
|
|
| 3. |
- Marqueze, Elaine C., et al.
(author)
-
Exogenous melatonin decreases circadian misalignment and body weight among early types
- 2021
-
In: Journal of Pineal Research. - : Wiley. - 0742-3098 .- 1600-079X. ; 71:2
-
Journal article (peer-reviewed)abstract
- 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/m(2), +/- 3.3 kg/m(2)). 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.
|
|
| 4. |
- Nogueira, Luciana F. R., et al.
(author)
-
Timing and Composition of Last Meal before Bedtime Affect Sleep Parameters of Night Workers
- 2021
-
In: Clocks & Sleep. - : MDPI AG. - 2624-5175. ; 3:4, s. 536-546
-
Journal article (peer-reviewed)abstract
- 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 x 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.
|
|
| 5. |
- Tiuganji, Natalia M., et al.
(author)
-
Eating Behavior (Duration, Content, and Timing) Among Workers Living under Different Levels of Urbanization
- 2020
-
In: Nutrients. - : MDPI AG. - 2072-6643. ; 12:2
-
Journal article (peer-reviewed)abstract
- 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.
|
|
| 6. |
- Vieira, R. P. O., et al.
(author)
-
High social jetlag is correlated with nocturnal inhibition of melatonin production among night workers
- 2021
-
In: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 38:8, s. 1170-1176
-
Journal article (peer-reviewed)abstract
- Night work can lead to social jetlag (SJL), which can be briefly defined as the difference between social and biological time. In this sense, SJL has been viewed as a proxy for circadian misalignment. Studies have suggested that SJL may modify physiological processes, such as blood pressure, glucose metabolism, cortisol, and melatonin production. Therefore, we aimed to verify the correlation between SJL and nocturnal inhibition of melatonin production estimated by the concentration of its urinary metabolite (6-sulfatoximelatonin). The study included day workers (n = 9) and night workers (n = 13) from a public maternity hospital in the city of Sao Paulo. A questionnaire was used to obtain sociodemographic data, life habits, working conditions, and the Munich Chronotype Questionnaire (MCTQ(shift)) was used to assess chronotype. Urine was collected on workdays and days off to estimate the concentration of 6-sulfatoximelatonin (aMT6s), quantified by the ELISA method. We found SJL 13 times higher for night workers (10.6 h) than day workers (0.8 h). The excretion of aMT6s in night workers was statistically different on workdays as opposed to days off, with the lowest excretion on workdays, as expected. SJL was correlated with the aMT6s's delta between the night off and night on among night workers, indicating that the higher is the SJL, the lower is the melatonin production. As expected, social jetlag was higher among night workers, compared to day workers. Moreover, our findings showed that melatonin concentration is directly correlated with SJL.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Nehme, P. A., et al.
(author)
-
Reduced melatonin synthesis in pregnant night workers : Metabolic implications for offspring
- 2019
-
In: Medical Hypotheses. - : Elsevier BV. - 0306-9877 .- 1532-2777. ; 132
-
Journal article (peer-reviewed)abstract
- Several novel animal studies have shown that intrauterine metabolic programming can be modified in the event of reduced melatonin synthesis during pregnancy, leading to glucose intolerance and insulin resistance in the offspring. It is therefore postulated that female night workers when pregnant may expose the offspring to unwanted health threats. This may be explained by the fact that melatonin is essential for regulating energy metabolism and can influence reproductive activity. Moreover, the circadian misalignment caused by shift work affects fertility and the fetus, increasing the risk of miscarriage, premature birth and low birth weight, phenomena observed in night workers. Thus, we hypothesize that light-induced melatonin suppression as a result of night work may alter intrauterine metabolic programming in pregnant women, potentially leading to metabolic disorders in their offspring.
|
|
