Sleep duration and body mass index: moderating effect of self-perceived stress and age. Results of a cross-sectional population-based study

Association between visual impairment and sleep duration in college students: A study conducted in UAE and Lebanon

Objective: To examine whether self-reported sleep duration and visual impairment were associated among College students. Participants: Students (n = 1002, age 17-35 years) from Lebanon and the United Arab Emirates. Methods: Students were asked to complete a validated questionnaire between October 2018 and May 2019. The questions were related to sociodemographics, lifestyle characteristics, visual impairment status, sleeping pattern, mobile-phone use and chronic conditions. Results: 18.3% of the respondents reported to suffer from visual impairment. Among them, 72.7% were females (p < .001), 65% admitted to frequently use mobile phones before sleeping (p < .001), 54.6% reported to sleep less than 7 h (p = .008) and 71.6% reported to suffer from sleep disturbances (p = .05). Visual impairment was associated with poor sleep quality (p < .001), mobile phone use before sleeping (p < .01) and daily stress (p < .05). Conclusion: Visual impairment in college students is associated with short sleep duration, mobile phone use before sleeping and stress level.

Sleep, Physical Activity, and Diet of Adults during the Second Lockdown of the COVID-19 Pandemic in Greece

The aim of the present study was to evaluate the possible correlations between sleep, physical activity, and diet in the general population of Greece during the second lockdown due to COVID-19 pandemic. A web-based questionnaire including 28 items was completed by 494 adults (age 31.5 ± 12.4 years). Half of the participants (49.8%) reported good, 44.1% moderate, and 6.1% bad quality of sleep, whereas 17.2% answered that the quality of sleep improved, 56.5% did not change, and 26.3% worsened compared to a normal week. Compared to normal, sleep duration in lockdown increased by 0.24 h (95% CI; 0.13, 0.35; p < 0.001, d = 0.198). More under-weight (32.4%) and obese (34.1%) respondents reported worsened quality of sleep in lockdown compared with normal (25.6%) and overweight participants (22.7%) (p = 0.006, Cramer's φ = 0.191). A small effect for BMI group on sleep duration was observed (p = 0.011, η2 = 0.023), where overweight and obese slept less (-0.44 h and -0.66 h, respectively) than normal weight participants. Subjects with the highest percentage of increased food consumption reported decreased sleep duration (p = 0.012) and worsened sleep quality (p = 0.003). Compared with a normal week, physical activity of a high and moderate intensity decreased for 43.0% and 37.0% of participants, did not change in 32.9% and 36.1% of participants, and increased in 24.1% 26.9%, respectively, whereas walking time decreased in 31.3%, did not change in 27.3%, and increased in 41.5% of participants. Increased high and moderate intensity physical activity was related with an improvement in sleep quality (p < 0.001). Those with decreasing walking time reported the highest percentage of decreased sleep quality (p = 0.006) and worsened sleep quality (p = 0.016). In conclusion, both quality and quantity of sleep were impaired during the second lockdown and the observed changes were associated with diet and physical activity.

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

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

Social jetlag and sleep deprivation are associated with altered activity in the reward-related brain areas: an exploratory resting-state fMRI study

OBJECTIVE

The aim of this research was to assess the effect of social jetlag (SJL) and its interaction with partial sleep deprivation on resting-state brain activity using the fractional amplitude of low-frequency fluctuation (fALFF) during free-living conditions.

METHODS

A total of 28 normal weight healthy subjects were enrolled in four study groups (with SJL [with sleep deprivation and without sleep deprivation] and without SJL [with sleep deprivation and without sleep deprivation]), matched 1:1:1:1 for age, gender, and body mass index (BMI). Resting-state functional magnetic resonance imaging (fMRI) scans were collected with SIEMENS 3T scanner while subjects were in a fasting state.

RESULTS

Participants with SJL had significantly higher fALFF values in right lingual gyrus and right putamen and significantly lower fALFF values in left and right inferior parietal lobe in comparison with participants without SJL and without sleep deprivation. Subjects with sleep deprivation had significantly higher fALFF in the thalamus and left superior frontal gyrus. In those with both SJL and sleep deprivation, we observed higher fALFF values in right Brodmann Area (BA)18 and lower values in left and right parietal inferior lobe. Subjects with SJL alone had significantly lower fALFF values in left frontal mid gyrus (BA6) than those with sleep deprivation alone.

CONCLUSIONS

SJL was associated with altered resting-state brain activity in regions that have been shown to be involved in hedonic feeding. The effect of SJL was independent of effects induced by short sleep duration. These alterations might represent the substrate for the increased risk of obesity observed in those with SJL.