Trends in self‐reported sleep problems,tiredness and related school performance among Finnish adolescents from 1984 to 2011

The aim of this study was to investigate long‐term trends in insomnia symptoms, tiredness and school performance among Finnish adolescents. A time–series from 1984 to 2011 was analysed from two large‐scale survey studies, the Finnish School Health Promotion Study and the Health Behavior in School‐Aged Children study. A total of 1 136 583 adolescents aged 11–18 years answered a standardized questionnaire assessing frequency of insomnia symptoms, tiredness and school performance. A clear approximately twofold increasing trend in insomnia symptoms and tiredness was found from the mid‐1990s to the end of the 2000s. The increase was evident in all participating age groups and in both genders. After 2008, the increase seems to have stopped. Insomnia symptoms and tiredness were associated with lower school performance and they were more prevalent among girls (11.9 and 18.4%) compared to boys (6.9 and 9.0%, respectively). Unexpectedly, we also observed an increasingly widening gap in school performance between normally vigilant and chronically tired pupils. The underlying causes of these phenomena are unknown, but may concern changes in the broader society. The observed recent increasing trend in adolescents’ sleep problems is worrisome: poor sleep quality has also been suggested to associate with clinical or subclinical mood or anxiety disorders and behavioural problems and predispose to sleep and psychiatric disorders later in life. Our results justify further studies and call for serious attention to be paid to adolescent's sleep in the Finnish educational system and society at large.     

Trajectories of reported sleep duration associate with early childhood cognitive development

Study ObjectivesExamine how different trajectories of reported sleep duration associate with early childhood cognition.MethodsCaregiver-reported sleep duration data (n = 330) were collected using the Brief Infant Sleep Questionnaire at 3, 6, 9, 12, 18, and 24 months and Children’s Sleep Habits Questionnaire at 54 months. Multiple group-based day-, night-, and/or total sleep trajectories were derived—each differing in duration and variability. Bayley Scales of Infant and Toddler Development-III (Bayley-III) and the Kaufman Brief Intelligence Test- 2 (KBIT-2) were used to assess cognition at 24 and 54 months, respectively.ResultsCompared to short variable night sleep trajectory, long consistent night sleep trajectory was associated with higher scores on Bayley-III (cognition and language), while moderate/long consistent night sleep trajectories were associated with higher KBIT-2 (verbal and composite) scores. Children with a long consistent total sleep trajectory had higher Bayley-III (cognition and expressive language) and KBIT-2 (verbal and composite) scores compared to children with a short variable total sleep trajectory. Moderate consistent total sleep trajectory was associated with higher Bayley-III language and KBIT-2 verbal scores relative to the short variable total trajectory. Children with a long variable day sleep had lower Bayley-III (cognition and fine motor) and KBIT-2 (verbal and composite) scores compared to children with a short consistent day sleep trajectory.ConclusionsLonger and more consistent night- and total sleep trajectories, and a short day sleep trajectory in early childhood were associated with better cognition at 2 and 4.5 years.     

Trajectories of sleep problems from childhood to adolescence: a population‐based longitudinal study from Norway

The aim of the current study was to assess the development and stability of sleep problems from childhood to late adolescence. This was a longitudinal cohort study of 2026 children, who completed three comprehensive health surveys, at age 7–9, 11–13 and 16–19 years. Data on difficulties with initiating and/or maintaining sleep (DIMS: assessed using a single item) and time in bed (TIB) were collected at all three waves, while insomnia assessed in line with the DSM‐5 criteria and sleep duration were also assessed in the last wave. Negative binomial regression analyses were used to examine prospective associations. Sleep problems in 7–9‐year‐old children were found to persist into late adolescence for approximately one‐third of the participants, both with regard to DIMS and short TIB. Children having chronic DIMS at the first two waves had nearly twice the risk of fulfilling the DSM‐5 criteria later for insomnia in late adolescence [adjusted relative risk RR: 1.91]. Short TIB at age 11–13 was also associated with increased risk of subsequent short sleep duration (adjusted RR: 1.32) and TIB (adjusted RR: 1.40). These findings have important implications for practitioners and families. Although the majority of children will outgrow their problems once they reach late adolescence, the results also demonstrate that sleep problems are likely to become chronic for one in every third child with a sleep problem early in life. Given the many negative consequences of insomnia in adulthood, these findings call for increased awareness of childhood sleep problems as a public health concern.     

Longitudinal associations of sleep problems with alcohol and cannabis use from adolescence to emerging adulthood

Study ObjectivesThis study examined longitudinal associations of sleep problems with alcohol and cannabis use across six annual waves of data from adolescence to emerging adulthood.MethodsParticipants were 3,265 youth from California (ages 16–22 across waves). At each wave, past-month alcohol use and cannabis use, mental health, and several dimensions of sleep health (i.e. social jetlag, bedtimes, time in bed, trouble sleeping) were assessed via questionnaire. Parallel process latent growth models examined the association between sleep and alcohol or cannabis use trajectories and the role of mental health in contributing to such trajectories.ResultsSmaller declines in social jetlag (r = 0.11, p = 0.04), increases in trouble sleeping (r = 0.18, p < 0.01), and later weekday (r = 0.16, p < 0.01) and weekend bedtimes (r = 0.25, p < 0.01) were associated with increases in likelihood of alcohol use over time. Declines in weekend TIB (r = −0.13, p = 0.03), as well as increases in weekday TIB (r = 0.11, p = 0.04) and later weekday (r = 0.18, p < 0.01) and weekend bedtime (r = 0.24, p < 0.01), were associated with increases in likelihood of cannabis use over time. Most associations remained significant after controlling for time-varying mental health symptoms.ConclusionsTrajectories of sleep health were associated with trajectories of alcohol and cannabis use during late adolescence to emerging adulthood. Improving sleep is an important target for intervention efforts to reduce the risk of substance use during this critical developmental transition.     

Self‐reported sleep duration and cognitive functioning in the general population

This study investigated the relationship between self‐reported sleep factors (sleep duration, insomnia, use of sleeping medicine, probable sleep apnoea and feelings of fatigue and tiredness) with cognitive functioning in 5177 people aged 30 years or older from a cross‐sectional representative sample of the adult population in Finland (The Finnish Health 2000 Survey). Previous studies have indicated a U‐shaped association between increased health risks and sleep duration; we hypothesized a U‐shaped association between sleep duration and cognitive functioning. Objective cognitive functioning was assessed with tasks derived from the Consortium to Establish a Registry for Alzheimer’s Disease test battery (verbal fluency, encoding and retaining verbal material). Subjective cognitive functioning and sleep‐related factors were assessed with questionnaires. Health status was assessed during a health interview. Depressive and alcohol use disorders were assessed with the Composite International Diagnostic Interview. Medication was recorded during the health examination. Short and long sleep duration, tiredness and fatigue were found to be associated with both objectively assessed and self‐reported decreased cognitive functioning. The association was stronger between sleep factors and subjective cognitive function than with objective cognitive tests. These data suggest that self‐reported habitual short and long sleep duration reflect both realization of homeostatic sleep need and symptom formation in the context of the individual’s health status.     

Development of sleep patterns in early adolescence

This study examines the developmental changes of sleep patterns as a function of gender and puberty and assesses the prevalence of sleep habits and sleep disturbances in early adolescence. It also investigates the relationship between sleep patterns, sleep habits and difficulty falling asleep and nocturnal awakenings. The present analyses are based on results available for 588 boys and 558 girls for whom mothers completed questions concerning demographics and sleep at annual intervals when their child was aged 10--13 years. The results indicated that nocturnal sleep times decreased, bedtimes were delayed and differences between weekend and school day sleep schedules progressively increased with age. Gender and puberty were both associated with the timing of sleep on weekends. Girls presented longer weekend time in bed (TIB) and later weekend wake time than boys. Similarly, subjects with higher pubertal status showed longer weekend TIB and later weekend wake time than subjects with lower pubertal status. Difficulty falling asleep was associated with later weekend wake time and with sleeping with a night light. In conclusion, the gender differences commonly reported in adolescents' sleep patterns are most likely explained by girls' higher pubertal status. This study emphasizes the link between puberty and a putative physiological need for more sleep, in presence of a general reduction of sleep times during adolescence. From age 10--13 years, the delay and lengthening of the sleep period on weekends in comparison to schooldays is associated with difficulty falling asleep.     

Self‐reported sleep quantity,quality and sleep hygiene in elite athletes

Sleep is essential for recovery and performance in elite athletes. While actigraphy‐based studies revealed suboptimal sleep in athletes, information on their subjective experience of sleep is scarce. Relatively unexplored is also the extent to which athletes’ sleep is adversely affected by environmental conditions and daytime behaviours, that is sleep hygiene. This study aimed to provide insight in sleep quantity, quality and its putative association with sleep hygiene. Participants were 98 elite (youth) athletes competing at the highest (inter‐)national level. Sleep quantity, quality and sleep hygiene were assessed once covering a 1‐month period by using established (sub)clinical questionnaires, and repeatedly during 7 consecutive days. Sleep quality was generally healthy, although 41% of all athletes could be classified as ‘poor sleeper’, and 12% were identified as having a sleep disorder. Daily self‐monitoring revealed sleep durations of 8:11 ± 0:45 h, but elevated wake after sleep onset of 13 ± 19 min. Sleep quality, feeling refreshed, and morning vigor were moderate at best. Regarding sleep hygiene, general measures revealed irregular sleep–wake patterns, psychological strain and activating pre‐sleep behaviours. At the daily level, blue‐light exposure and late‐evening consumption of heavy meals were frequently reported. General sleep hygiene revealed significant associations with sleep quality (0.45 < r > 0.50; P < 0.001). Results indicate that there is ample room for optimization, specifically in onset latency and in wake after sleep onset. Subtle improvements in sleep seem possible, and optimizing sleep hygiene, such as regular sleep–wake patterns and reducing psychological strain, may facilitate this sleep upgrading process.     

An approach to understanding sleep and depressed mood in adolescents: person‐centred sleep classification

Depressive mood in youth has been associated with distinct sleep dimensions, such as timing, duration and quality. To identify discrete sleep phenotypes, we applied person‐centred analysis (latent class mixture models) based on self‐reported sleep patterns and quality, and examined associations between phenotypes and mood in high‐school seniors. Students (n = 1451; mean age = 18.4 ± 0.3 years; 648 M) completed a survey near the end of high‐school. Indicators used for classification included school night bed‐ and rise‐times, differences between non‐school night and school night bed‐ and rise‐times, sleep‐onset latency, number of awakenings, naps, and sleep quality and disturbance. Mood was measured using the total score on the Center for Epidemiologic Studies‐Depression Scale. One‐way anova tested differences between phenotype for mood. Fit indexes were split between 3‐, 4‐ and 5‐phenotype solutions. For all solutions, between phenotype differences were shown for all indicators: bedtime showed the largest difference; thus, classes were labelled from earliest to latest bedtime as ‘A’ (n = 751), ‘B’ (n = 428) and ‘C’ (n = 272) in the 3‐class solution. Class B showed the lowest sleep disturbances and remained stable, whereas classes C and A each split in the 4‐ and 5‐class solutions, respectively. Associations with mood were consistent, albeit small, with class B showing the lowest scores. Person‐centred analysis identified sleep phenotypes that differed in mood, such that those with the fewest depressive symptoms had moderate sleep timing, shorter sleep‐onset latencies and fewer arousals. Sleep characteristics in these groups may add to our understanding of how sleep and depressed mood associate in teens.     

Effects of cumulative sleep restriction on self‐perceptions while multitasking

This study addressed a rarely studied question of self‐perceptions of performance and overall functional state during cumulative sleep restriction and the ensuing recovery period. Twenty healthy male volunteers, aged 19–29 years, were divided into a sleep restriction group (n = 13) and a control group (n = 7). On the first 2 nights, the sleep restriction group had an 8‐h sleep opportunity that was restricted to 4 h for the next 5 nights, and then restored to 8 h for the last 2 nights. The control group had an 8‐h sleep opportunity each night. Each day participants accomplished 50‐min multitask sessions and gave self‐ratings in their connection. Similar to our previous findings on multitasking performance, self‐perceived task performance, sleepiness and mental fatigue impaired during the sleep restriction and returned to baseline during the recovery phase. Self‐perceived mental effort, tension, task difficulty and task pace showed no sensitivity to the sleep restriction. We concluded that sleep‐restricted individuals can probably make use of some self‐perceptions when assessing their ‘fitness for duty’. However, at the individual level these measures seem to be inaccurate in revealing actual performance impairments.     

Associations between objectively measured and self‐reported sleep with academic and cognitive performance in adolescents: DADOS study

Adequate sleep has been positively related with health and school achievement outcomes during adolescence. The aim of this study was to investigate the associations of objectively measured and self‐reported sleep duration and quality with academic and cognitive performance in adolescents. This study was conducted with 257 adolescents (13.9 ± 0.3 years) from the DADOS study (Deporte, ADOlescencia y Salud). Objectively measured and self‐reported sleep duration and quality were obtained by a wrist‐worn GENEActiv accelerometer and the Spanish version of Pittsburgh Sleep Quality Index questionnaire, respectively. Academic performance was analysed through school records using four indicators: math, language, science and grade point average score. Cognitive performance was measured using the Spanish version of the “SRA Test of Educational Ability”. After Benjamini–Hochberg correction for the false discovery rate, objectively measured sleep duration was negatively associated with verbal ability (β = ?0.179, p = .004), whilst self‐reported sleep quality was positively associated with academic performance (β ranging from 0.209 to 0.273; all p < .001). These associations remained significant after further controlling for physical fitness and physical activity. Conversely, there were no associations between self‐reported sleep duration and objective sleep quality with academic and cognitive performance. Our findings fit in line with previous research showing that sleep quality may play an important role on adolescents’ academic performance. Further interventional research is needed to clarify the mechanisms by which sleep is related to academic performance in youth.     

Infant feeding practices and sleep development in pre‐schoolers from the EDEN mother–child cohort

Sleep problems affect 20%–30% of toddlers and preschoolers. Few longitudinal studies focused on the impact of infant feeding practices on sleep. We aimed to study the associations between feeding practices up to 8 months and trajectories of sleep quantity or quality from 2 to 5–6 years. Analyses included 1,028 children from the EDEN mother–child cohort. Data were collected by self‐administered questionnaires. Associations between feeding practices (breastfeeding, complementary feeding, use of thickened infant formula, night feeding) and sleep trajectories (sleep‐onset difficulties, night waking, nighttime in bed) were analysed by multiple logistic regressions. Predominant breastfeeding for more than 4 months was associated with lower risk for belonging to the persistent sleep‐onset difficulties trajectory. Night feeding at 4 months or at 2 years old was associated with higher risk for belonging to the persistent sleep‐onset difficulties trajectory, and night feeding at 8 months was associated with higher risk for night waking and higher risk for short nighttime in bed. Early introduction (< 4 months) to complementary foods (excluding baby cereals) was related to lower risk for short nighttime in bed. Use of baby cereals or thickened infant formula was related neither to sleep quality nor to sleep quantity. In conclusion, infant feeding practices are associated with sleep trajectories in preschoolers, with notably a potential protective role of breastfeeding. Further researches are needed to clarify the mechanisms of these relationships.     

Increasing sleep duration to lower beat‐to‐beat blood pressure: a pilot study

Strong evidence has accumulated over the last several years, showing that low sleep quantity and/or quality plays an important role in the elevation of blood pressure. We hypothesized that increasing sleep duration serves as an effective behavioral strategy to reduce blood pressure in prehypertension or type 1 hypertension. Twenty‐two participants with prehypertension or stage 1 hypertension, and habitual sleep durations of 7 h or less, participated in a 6‐week intervention study. Subjects were randomized to a sleep extension group (48 ± 12 years, N = 13) aiming to increase bedtime by 1 h daily over a 6‐week intervention period, or to a sleep maintenance group (47 ± 12 years, N = 9) aiming to maintain habitual bedtimes. Both groups received sleep hygiene instructions. Beat‐to‐beat blood pressure was monitored over 24 h, and 24‐h urine and a fasting blood sample were collected pre‐ and post‐intervention. Subjects in the sleep extension group increased their actigraphy‐assessed daily sleep duration by 35 ± 9 min, while subjects in the sleep maintenance condition increased slightly by 4 ± 9 min (P = 0.03 for group effect). Systolic and diastolic beat‐to‐beat blood pressure averaged across the 24‐h recording period significantly decreased from pre‐ to post‐intervention visit in the sleep extension group by 14 ± 3 and 8 ± 3 mmHg, respectively (P < 0.05). Though the reduction of 7 ± 5 and 3 ± 4 mmHg in the sleep maintenance group was not significant, it did not differ from the blood pressure reduction in the sleep extension group (P = 0.15 for interaction effect). These changes were not paralleled by pre‐ to post‐intervention changes in inflammatory or sympatho‐adrenal markers, nor by changes in caloric intake. While these preliminary findings have to be interpreted with caution due to the small sample size, they encourage future investigations to test whether behavioral interventions designed to increase sleep duration serve as an effective strategy in the treatment of hypertension.     

Trajectories of marijuana use from adolescence to young adulthood: predictors and outcomes

Semiparametric group-based mixture modeling was used with data from an adolescent school sample (N = 1205) for three purposes. First, five trajectory groups were identified to characterize different patterns of change in the frequency of marijuana use across four waves of assessment during adolescence. These trajectory groups were labeled Abstainers, Experimental Users, Decreasers, Increasers, and High Chronics. Second, trajectory group comparisons were made across eight adolescent risk factors to determine distinctive predictors of the trajectory groups. Findings indicated, for example, that the High Chronic group, relative to the other trajectory groups, had higher levels of delinquency, lower academic performance, more drug using friends, and more stressful life events. Third, adolescent trajectory group comparisons were made across 10 risk behaviors in young adulthood (average subject age = 23.5 years) and the occurrence of psychiatric and substance abuse disorders. Findings indicated some consistency across adolescence to young adulthood with regard to risk factors, and specificity with regard to the prediction of disorders. Adolescent trajectory group membership was significantly associated in young adulthood with cannabis and alcohol disorders but not with major depressive disorders or anxiety disorders.     

Inequalities in smoking: Influence of social chain of risks from adolescence to young adulthood: A prospective population-based cohort study

Background: The pathway between socioeconomic disadvantages and smoking is a process that requires an understanding of life-course influence. Purpose: This study investigated pathways of social risks at different life stages that are linked to adolescent smoking and maintenance of smoking through to young adulthood. Method: A cohort consisting of all pupils (n = 1083) from one Swedish city were followed from age 16 to age 30 (1981 & #x2013;1995), with a 96.4% response rate. Result: Odds ratios of being a smoker at age 30 among low educated were 2.54 for men and 2.53 for women. Using structural equation model analysis for men and women, a strong chain of risks was found from age 16 linking to smoking at age 30: adolescents with adverse socioeconomic status (SES) were more likely from a divorced family. Being from a divorced family and having poor contact with their parents influenced their smoking directly and through peers. Adolescents with adverse SES were also likely to be unpopular in school, which affected their smoking behavior directly and through peers. These socially disadvantaged participants, who were smokers at age 16, continued smoking until age 30 years. The risk pathways were similar for both men and women. Conclusions: Adult smoking reflects the cumulative influence of multiple socioeconomic and psychosocial chains of risks experienced during upbringing. The programs that are addressed to reduce smoking among socially disadvantaged adolescents would have an impact in reducing smoking inequalities in adults. This study was financed by the Swedish Council for Working Life and Social Research and the National Institute of Public Health, Sweden. The authors would like to thank Hans Stenlund, University Lecturer in Statistics, for assistance with the data analysis.     

Defining short and long sleep duration for future paediatric research: A systematic literature review

Short and long sleep patterns in children have been associated with a range of poor health outcomes. However, there is no consensus regarding the definitions of these abnormal sleep parameters in childhood for use in paediatric research. Given that there is a clear lack of definitions for sleep duration throughout paediatric sleep literature, this review aimed to establish recommendations for standard cut‐offs of short and long sleep for children aged 1–16 years to enable homogeneity in future studies of paediatric sleep duration. Four databases were systematically searched to identify prospective studies that defined short or long sleep patterns in children. Included papers (38) were assessed for methodological quality, and their definitions were extracted to examine the current applied cut‐offs in the literature for short or long sleep duration. The definitions were analysed in a regression model to summarize applied cut‐offs from subjective data into cut‐offs for short and long sleep duration. These models were fitted to reference values of three commonly cited paediatric population studies to establish new definitions of sleep duration for future use in research. Across the age groups there was little consensus in applied cut‐offs for short and long sleep duration. This study found the best compromise for short sleep was defined as the 2.5th centile (hours = 0.25*age + 11) and long sleep as the 97.5th centile (hours = 0.017*age² ? 0.68*age + 16) of sleep duration in children. Recommendations for the hourly cut‐offs of short and long sleep duration based on these percentiles were described.     

Mother‐reported sleep,accelerometer‐estimated sleep and weight status in Mexican American children: sleep duration is associated with increased adiposity and risk for overweight/obese status

We know of no studies comparing parent‐reported sleep with accelerometer‐estimated sleep in their relation to paediatric adiposity. We examined: (i) the reliability of mother‐reported sleep compared with accelerometer‐estimated sleep; and (ii) the relationship between both sleep measures and child adiposity. The current cross‐sectional study included 303 Mexican American mother–child pairs recruited from Kaiser Permanente Northern California. We measured sleep duration using maternal report and accelerometry and child anthropometrics. Concordance between sleep measures was evaluated using the Bland–Altman method. We conducted zero‐ordered correlations between mother‐reported sleep, accelerometer‐estimated sleep and child BMI z‐scores (BMIz). Using linear regression, we examined three models to assess child BMIz with mother‐reported sleep (model 1), accelerometer‐estimated sleep (model 2) and both sleep measures (model 3). Children had an average age of 8.86 years (SD = 0.82). Mothers reported that their child slept 9.81 ± 0.74 h [95% confidence interval (CI): 9.72, 9.89], compared to 9.58 ± 0.71 h (95% CI: 9.50, 9.66) based on accelerometry. Mother‐reported sleep and accelerometer‐estimated sleep were correlated (r = 0.33, P < 0.001). BMIz outcomes were associated negatively with mother‐reported sleep duration (model 1: β = ?0.13; P = 0.02) and accelerometer‐estimated sleep duration (model 2: β = ?0.17; P < 0.01). Accounting for both sleep measures, only accelerometer‐measured sleep was related to BMIz (model 3: β = ?0.14, P = 0.02). Each sleep measure was related significantly to adiposity, independent of covariates. Accelerometry appeared to be a more reliable measure of children's sleep than maternal report, yet maternal report may be sufficient to examine the sleep–adiposity relationship when resources are limited.