Sleep quality and duration: A key to life satisfaction among military students.

Military service is a demanding profession that requires high physical preparedness and mental endurance. At the same time, the demands of military duties often require early rising and shortened sleep duration. Such a reduction in sleep can reduce physical and mental performance, and these changes can be reflected in life satisfaction. For this reason, soldiers' life satisfaction is a crucial variable for their success and long-term service. This study examined the relationship between sleep quality, sleep duration, and life satisfaction in military medical students. The results on 35 military students showed that greater sleep quality corresponded to greater life satisfaction; this relationship was moderate and significant (r = -460, p = .005). Notably, participants (n = 17) who began to wake up without the use of an alarm clock reported an average of 11% higher life satisfaction than the participants who woke to an alarm clock; this difference between participants was statistically significant (p = .011, Cohen's d = .911). Pre- and post-intervention showed that sleep hygiene education could be a suitable solution to prevent sleep deprivation and positively impact life satisfaction. Our findings emphasize the importance of increased sleep hygiene education, especially in preparing future military officers and during military exercises. Prioritizing sleep hygiene in these ways can significantly increase soldiers' life satisfaction.

Does the feeding method affect the quality of infant and maternal sleep? A systematic review.

Breastfeeding brings many benefits to both mother and infant. Although, many women stop breastfeeding their infants too soon. The perceived association between breastfeeding and sleep may influence their decision to terminate breastfeeding. In our systematic review, we focused on mapping the relationship between infant feeding method and total sleep time (TST), number of nocturnal awakenings, awakenings after sleep onset (WASO) of mothers and infants and sleep quality of mothers. We searched four databases according to selected keywords and inclusion criteria - articles published in peer-reviewed journals between 2012 and 2022; English language; a sample consisting of mothers, infants, or both (without psychiatric and health problems); a comparison of the sleep quality of breastfed and formula-fed children or breastfeeding and formula-fed mothers. We read 260 full texts of selected articles. A total of 35 articles were included in this review. Due to significant heterogeneity, meta-analysis was not possible to accomplish. The results are processed according to narrative synthesis. Most studies agree that breastfed infants wake up more often at night. Total sleep time and time spent awake during the night (WASO) did not differ between breastfed and non-breastfed infants. We observed identical results in sleep variables among mothers. Additionally, there was no difference in maternal sleep quality. The synthesis revealed that the results may have differed due to using subjective, objective methods or the infant's age. It is important to remember that night waking is a more complex concept. Infants wake for many reasons, not just due to breastfeeding. The narrative synthesis indicated that the chosen study design, measurement method, the variables, and the infant's age could influence outcomes. In addition, other variables appeared that may affect the entire process. Therefore, we recommend that attention be paid to this in future studies.

Validation of the Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT) questionnaire for adults.

BACKGROUND: The Collaborative Outcome study on Health and Functioning during Infection Times (COH-FIT; www.coh-fit.com) is an anonymous and global online survey measuring health and functioning during the COVID-19 pandemic. The aim of this study was to test concurrently the validity of COH-FIT items and the internal validity of the co-primary outcome, a composite psychopathology "P-score". METHODS: The COH-FIT survey has been translated into 30 languages (two blind forward-translations, consensus, one independent English back-translation, final harmonization). To measure mental health, 1-4 items ("COH-FIT items") were extracted from validated questionnaires (e.g. Patient Health Questionnaire 9). COH-FIT items measured anxiety, depressive, post-traumatic, obsessive-compulsive, bipolar and psychotic symptoms, as well as stress, sleep and concentration. COH-FIT Items which correlated r ≥ 0.5 with validated companion questionnaires, were initially retained. A P-score factor structure was then identified from these items using exploratory factor analysis (EFA) and confirmatory factor analyses (CFA) on data split into training and validation sets. Consistency of results across languages, gender and age was assessed. RESULTS: From >150,000 adult responses by May 6th, 2022, a subset of 22,456 completed both COH-FIT items and validated questionnaires. Concurrent validity was consistently demonstrated across different languages for COH-FIT items. CFA confirmed EFA results of five first-order factors (anxiety, depression, post-traumatic, psychotic, psychophysiologic symptoms) and revealed a single second-order factor P-score, with high internal reliability (ω = 0.95). Factor structure was consistent across age and sex. CONCLUSIONS: COH-FIT is a valid instrument to globally measure mental health during infection times. The P-score is a valid measure of multidimensional mental health.

The circadian preferences in the context of sociodemographic indicators and lifestyle.

Circadian preferences are frequently used as a synonym for chronotype. Both terms are based on different principles and are measured by a variant questionnaire. We focused on circadian preferences, delimited as an individual preference for the timing of various activities, and their relationship to the selected sociodemographic factors. All participants (n = 2068) filled out online questionnaires including MEQ, MCTQ, and sociodemographic information (age, sex, place of residence, marital status, childcare, education, financial security, physical and mental health). Although the concept of chronotype and circadian preference differ, the mutual correlation was high. Our results of the observed variables are similar to other studies. We revealed evening preference is related to a higher probability of living in a big city, having a single life, a higher risk of smoking, worse health status, and worse financial security. We observed a higher social jet lag among them. Our research complies with previous studies, which found that in some areas, people with evening preferences evince worse results. Due to the evening preference, these people are at a disadvantage, and the society's setting for morning operations can lead to a deepening of these differences. We recommend further research, which would focus on the practical application of results to the everyday life of participants to create preventive programs aimed at reducing the negative impact of evening preferences on life.

The collaborative outcomes study on health and functioning during infection times in adults (COH-FIT-Adults): Design and methods of an international online survey targeting physical and mental health effects of the COVID-19 pandemic.

BACKGROUND: . High-quality comprehensive data on short-/long-term physical/mental health effects of the COVID-19 pandemic are needed. METHODS: . The Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT) is an international, multi-language (n=30) project involving >230 investigators from 49 countries/territories/regions, endorsed by national/international professional associations. COH-FIT is a multi-wave, on-line anonymous, cross-sectional survey [wave 1: 04/2020 until the end of the pandemic, 12 months waves 2/3 starting 6/24 months threreafter] for adults, adolescents (14-17), and children (6-13), utilizing non-probability/snowball and representative sampling. COH-FIT aims to identify non-modifiable/modifiable risk factors/treatment targets to inform prevention/intervention programs to improve social/health outcomes in the general population/vulnerable subgrous during/after COVID-19. In adults, co-primary outcomes are change from pre-COVID-19 to intra-COVID-19 in well-being (WHO-5) and a composite psychopathology P-Score. Key secondary outcomes are a P-extended score, global mental and physical health. Secondary outcomes include health-service utilization/functioning, treatment adherence, functioning, symptoms/behaviors/emotions, substance use, violence, among others. RESULTS: . Starting 04/26/2020, up to 14/07/2021 >151,000 people from 155 countries/territories/regions and six continents have participated. Representative samples of ≥1,000 adults have been collected in 15 countries. Overall, 43.0% had prior physical disorders, 16.3% had prior mental disorders, 26.5% were health care workers, 8.2% were aged ≥65 years, 19.3% were exposed to someone infected with COVID-19, 76.1% had been in quarantine, and 2.1% had been COVID 19-positive. LIMITATIONS: . Cross-sectional survey, preponderance of non-representative participants. CONCLUSIONS: . Results from COH-FIT will comprehensively quantify the impact of COVID-19, seeking to identify high-risk groups in need for acute and long-term intervention, and inform evidence-based health policies/strategies during this/future pandemics.

Physical and mental health impact of COVID-19 on children, adolescents, and their families: The Collaborative Outcomes study on Health and Functioning during Infection Times - Children and Adolescents (COH-FIT-C&A).

BACKGROUND: The COVID-19 pandemic has altered daily routines and family functioning, led to closing schools, and dramatically limited social interactions worldwide. Measuring its impact on mental health of vulnerable children and adolescents is crucial. METHODS: The Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT - www.coh-fit.com) is an on-line anonymous survey, available in 30 languages, involving >230 investigators from 49 countries supported by national/international professional associations. COH-FIT has thee waves (until the pandemic is declared over by the WHO, and 6-18 months plus 24-36 months after its end). In addition to adults, COH-FIT also includes adolescents (age 14-17 years), and children (age 6-13 years), recruited via non-probability/snowball and representative sampling and assessed via self-rating and parental rating. Non-modifiable/modifiable risk factors/treatment targets to inform prevention/intervention programs to promote health and prevent mental and physical illness in children and adolescents will be generated by COH-FIT. Co-primary outcomes are changes in well-being (WHO-5) and a composite psychopathology P-Score. Multiple behavioral, family, coping strategy and service utilization factors are also assessed, including functioning and quality of life. RESULTS: Up to June 2021, over 13,000 children and adolescents from 59 countries have participated in the COH-FIT project, with representative samples from eleven countries. LIMITATIONS: Cross-sectional and anonymous design. CONCLUSIONS: Evidence generated by COH-FIT will provide an international estimate of the COVID-19 effect on children's, adolescents' and families', mental and physical health, well-being, functioning and quality of life, informing the formulation of present and future evidence-based interventions and policies to minimize adverse effects of the present and future pandemics on youth.

Reliability and Validity of the Czech Version of the Pittsburgh Sleep Quality Index in Patients with Sleep Disorders and Healthy Controls.

OBJECTIVES: Psychometric properties of the Czech version of the Pittsburgh Sleep Quality Index (PSQI-CZ) have been evaluated only in patients with chronic insomnia, and thus, it is unclear whether PSQI-CZ is suitable for use in other clinical and nonclinical populations. This study was aimed at examining the validity and reliability of the PSQI-CZ and at assessing whether the unidimensional or multidimensional scoring of the instrument would be recommended. METHODS: A total of 524 adult subjects from the Czech population participated in the study. The internal consistency of PSQI was evaluated using Cronbach's alpha. The known-group validity was tested using the Kruskal-Wallis H test to verify the difference between patients with sleep disorders and healthy control sample. For testing the structural validity, a cross-validation approach was used with both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). For EFA, the maximum likelihood method with direct oblimin rotation and parallel analysis was used. RESULTS: The internal consistency of PSQI-CZ items was moderate (α = 0.75). Receiver operating characteristic (ROC) curve analysis showed high specificity (0.79) and moderate sensitivity (0.64) using an optimal cut-off score of 10. The EFA revealed a 3-factor structure with factors labelled as "sleep duration and efficiency," "sleep disturbances and quality," and "sleep latency." The CFA showed that the emerged 3-factor model had a partly acceptable fit, which was better than other previously supported models. CONCLUSIONS: A high cut-off score of 10 is recommended to define poor sleep quality. Given the inconsistency of structural analyses, alternative scoring was not recommended. However, the individual components in addition to a total score should be interpreted when assessing sleep quality. We recommend editing and verifying the PSQI-CZ translation.

Comparison of Munich Chronotype Questionnaire (MCTQ) and Morningness-Eveningness Questionnaire (MEQ) Czech version.

A chronotype is a designation for individual preference of times for different activities in humans. In chronobiological research, it can be measured in many ways, including subjective questionnaires. The most frequently used questionnaires for determining the chronotype are Morningness-Eveningness Questionnaire (MEQ) and Munich Chronotype Questionnaire (MCTQ). Many studies from around the world have already reported metric properties of the MEQ and MCTQ and their relationship in different languages. In this study, we created the Czech version of the MCTQ and examined its relationship with the Czech version of MEQ, including socio-demographic effects. We also examined the ability of the MCTQ to identify chronotypes and cutoffs for their determination. In total, 2703 people (1964 females, 739 males, 18-75 years of age) were screened by the MEQ, MCTQ and reported on age, sex and self-declared body mass index (BMI). We found a significant relationship (p < .001) between MEQ and MCTQ (MSFsc score, used as a chronotype indicator). No significant sex differences in MEQ and in MSFsc were found, but the relationship between age and MSFsc (mid-sleep on free days corrected for sleep debt on weekdays) (p < .001), MEQ (p < .001), social jet-lag (SJL, p < .001) and BMI (p < .001) were found. The SJL was related to MSFsc (p < .001), MEQ (p < .001) and BMI (p < .05). The optimal cutoff value of MSFsc to identify morning and evening chronotype was 3.35 and 4.6, respectively. The results of this study support the mutual substitutability of the Czech version of MEQ and MCTQ.

Evening and night exposure to screens of media devices and its association with subjectively perceived sleep: Should "light hygiene" be given more attention?

OBJECTIVE: The aim of the study was to examine subjective sleep quality in a population of healthy volunteers and its association with evening and night light exposure to screens of media devices. METHODS: A total of 693 participants (mean age 31.2±11.4 years, 159 men, and 538 women) completed an online questionnaire battery consisting of several sleep-related questionnaires: PSQI, FSS, MCTQ, MEQ, and added questions assessing the timing and character the evening and night exposure to electronical devices (TV, PC, tablets, and phones), and the use of various filters blocking short-wavelength light. RESULTS: Statistical analyses show that longer cumulative exposure to screen light in the evening was associated with greater sleep inertia in the morning (P = .019, η2=0.141) and longer sleep latency on workdays P = .038, η2=0.135). Furthermore, exposure to screen light 1.5 h before sleep or during night awakenings was also associated with a decreased chance to wake up before alarm clock (P = .003, d=0.30), larger social jet lag (P < .001, d=0.15), more daytime dysfunction (P < .001, d=0.40), decreased subjective sleep quality (P = .024, d=0.16), and more fatigue (P < .001, d=0.52). A statistical trend for an increase in duration of sleep on weekdays (P = .058, d=0.23) was also found in participants using blue-light filters in the evening hours. DISCUSSION: Our results are in line with other studies that converge to show the negative association of evening and night exposure to short-wavelength light on subjective and objective sleep parameters. Results suggest that light hygiene in general population should be given more attention not only in the context of clinical sleep medicine but also in the realm of public health.

Cross-sectional and within-subject seasonality and regularity of hospitalizations: A population study in mood disorders and schizophrenia.

BACKGROUND: Seasonal peaks in hospitalizations for mood disorders and schizophrenia are well recognized and often replicated. The within-subject tendency to experience illness episodes in the same season, that is, seasonal course, is much less established, as certain individuals may temporarily meet criteria for seasonal course purely by chance. AIMS: In this population, prospective cohort study, we investigated whether between and within-subject seasonal patterns of hospitalizations occurred more frequently than would be expected by chance. METHODS: Using a compulsory, standardized national register of hospitalizations, we analyzed all admissions for mood disorders and schizophrenia in the Czech Republic between 1994 and 2013. We used bootstrap tests to compare the observed numbers of (a) participants with seasonal/regular course and (b) hospitalizations in individual months against empirical distributions obtained by simulations. RESULTS: Among 87 184 participants, we found uneven distribution of hospitalizations, with hospitalization peaks for depression in April and November (X2 (11) = 363.66, P < .001), for mania in August (X2 (11) = 50.36, P < .001) and for schizophrenia in June (X2 (11) = 70.34, P < .001). Significantly more participants than would be expected by chance, had two subsequent rehospitalizations in the same 90 days in different years (7.36%, bootstrap P < .01) or after a regular, but non-seasonal interval (6.07%, bootstrap P < .001). The proportion of participants with two consecutive hospitalizations in the same season was below chance level (7.06%). CONCLUSIONS: Psychiatric hospitalizations were unevenly distributed throughout the year (cross-sectional seasonality), with evidence for regularity, but not seasonality of hospitalizations within subjects. Our data do not support the validity of seasonal pattern specifier. Season may be a general risk factor, which increases the risk of hospitalizations across psychiatric participants.