Insomnia with Short Sleep Duration and Mortality: The Penn State Cohort

Study Objectives:

Because insomnia with objective short sleep duration is associated with increased morbidity, we examined the effects of this insomnia subtype on all-cause mortality.

Design:

Longitudinal.

Setting:

Sleep laboratory.

Participants:

1,741 men and women randomly selected from Central Pennsylvania.

Measurements:

Participants were studied in the sleep laboratory and were followed-up for 14 years (men) and 10 years (women). “Insomnia” was defined by a complaint of insomnia with duration ≥ 1 year. “Normal sleeping” was defined as absence of insomnia. Polysomnographic sleep duration was classified into two categories: the “normal sleep duration group” subjects who slept ≥ 6 h and the “short sleep duration group” subjects who slept < 6 h. We adjusted for age, race, education, body mass index, smoking, alcohol, depression, sleep disordered breathing, and sampling weight.

Results:

The mortality rate was 21% for men and 5% for women. In men, mortality risk was significantly increased in insomniacs who slept less than 6 hours compared to the “normal sleep duration, no insomnia” group, (OR = 4.00, CI 1.14-13.99) after adjusting for diabetes, hypertension, and other confounders. Furthermore, there was a marginally significant trend (P = 0.15) towards higher mortality risk from insomnia and short sleep in patients with diabetes or hypertension (OR = 7.17, 95% CI 1.41-36.62) than in those without these comorbid conditions (OR = 1.45, 95% CI 0.13-16.14). In women, mortality was not associated with insomnia and short sleep duration.

Conclusions:

Insomnia with objective short sleep duration in men is associated with increased mortality, a risk that has been underestimated.

Citation:

Vgontzas AN; Liao D; Pejovic S; Calhoun S; Karataraki M; Basta M; Fernández-Mendoza J; Bixler EO. Insomnia with short sleep duration and mortality: the Penn State Cohort. SLEEP 2010;33(9):1159-1164.     

Insomnia with Objective Short Sleep Duration is Associated with Deficits in Neuropsychological Performance: A General Population Study

Study Objectives:

To examine the joint effect of insomnia and objective short sleep duration on neuropsychological performance.

Design:

Representative cross-sectional study.

Setting:

Sleep laboratory.

Participants:

1,741 men and women randomly selected from central Pennsylvania.

Interventions:

None.

Measurements:

Insomnia (n = 116) was defined by a complaint of insomnia with a duration ≥ 1 year and the absence of sleep disordered breathing (SDB), while normal sleep (n = 562) was defined as the absence of insomnia, excessive daytime sleepiness, and SDB. Both groups were split according to polysomnographic sleep duration into 2 categories: ≥ 6 h of sleep (“normal sleep duration”) and < 6 h of sleep (“short sleep duration”). We compared the groups'' performance on a comprehensive neuropsychological battery that measured processing speed, attention, visual memory, and verbal fluency, while controlling for age, race, gender, education, body mass index, and physical and mental health.

Results:

No significant differences were detected between insomniacs and controls. However, the insomnia with short sleep duration group compared to the control with normal or short sleep duration groups showed poorer neuropsychological performance in variables such as processing speed, set-switching attention, and number of visual memory errors and omissions. In contrast, the insomnia with normal sleep duration group showed no significant deficits.

Conclusions:

Insomnia with objective short sleep duration is associated with deficits in set-switching attentional abilities, a key component of the “executive control of attention.” These findings suggest that objective sleep duration may predict the severity of chronic insomnia, including its effect on neurocognitive function.

Citation:

Fernandez-Mendoza J; Calhoun S; Bixler EO; Pejovic S; Karataraki M; Liao D; Vela-Bueno A; Ramos-Platon MJ; Sauder KA; Vgontzas AN. Insomnia with objective short sleep duration is associated with deficits in neuropsychological performance: a general population study. SLEEP 2010;33(4):459-465.     

The Multidimensional Correlates Associated With Short Nocturnal Sleep Duration and Subjective Insomnia Among Taiwanese Adolescents

Study Objectives:

The aim of this study was to examine the correlates associated with short nocturnal sleep duration and subjective insomnia, including individual factors, family factors, peer factors, school factors, and the problematic use of high-tech devices among a large-scale representative population of Taiwanese adolescents.

Design:

Cross-sectional study.

Setting:

A total of 23 junior high and 29 senior high/vocational schools were randomly selected across southern Taiwan.

Participants:

Eight thousand four adolescent students.

Interventions:

N/A.

Measurements and Results:

The multidimensional correlates associated with short nocturnal sleep duration and subjective insomnia were examined using χ² automatic interaction detection analysis and logistic regression analysis models. The results indicated that an older age, self-reported depression, being in the third year of school, drinking coffee at night, and problematic Internet use were significantly associated with short nocturnal sleep duration in adolescents. Furthermore, self-reported depression, low school affinity, high family conflict, low connectedness to their peer group, and problematic Internet use were associated with subjective insomnia in adolescents.

Conclusions:

The results of this study indicate that a variety of individual, family, peer, and school factors were associated with short nocturnal sleep duration and subjective insomnia in adolescents. Furthermore, the correlates of short sleep duration were not identical to those of subjective insomnia. Parents and health professionals should be wary of sleep patterns among adolescents who have the identified correlates of short nocturnal sleep duration and subjective insomnia.

Citation:

Yen CF; Ko CH; Yen JY; Cheng CP. The multidimensional correlates associated with short nocturnal sleep duration and subjective insomnia among Taiwanese adolescents. SLEEP 2008;31(11):1515–1525.     

Association of Sleep Duration with Mortality from Cardiovascular Disease and Other Causes for Japanese Men and Women: the JACC Study

Study Objectives:

To examine sex-specific associations between sleep duration and mortality from cardiovascular disease and other causes.

Design:

Cohort study.

Setting:

Community-based study.

Participants:

A total of 98,634 subjects (41,489 men and 57,145 women) aged 40 to 79 years from 1988 to 1990 and were followed until 2003.

Interventions:

N/A.

Measurements and Results:

During a median follow-up of 14.3 years, there were 1964 deaths (men and women: 1038 and 926) from stroke, 881 (508 and 373) from coronary heart disease, 4287 (2297 and 1990) from cardiovascular disease, 5465 (3432 and 2033) from cancer, and 14,540 (8548 and 5992) from all causes. Compared with a sleep duration of 7 hours, sleep duration of 4 hours or less was associated with increased mortality from coronary heart disease for women and noncardiovascular disease/noncancer and all causes in both sexes. The respective multivariable hazard ratios were 2.32 (1.19–4.50) for coronary heart disease in women, 1.49 (1.02–2.18) and 1.47 (1.01–2.15) for noncardiovascular disease/noncancer, and 1.29 (1.02–1.64) and 1.28 (1.03–1.60) for all causes in men and women, respectively. Long sleep duration of 10 hours or longer was associated with 1.5- to 2-fold increased mortality from total and ischemic stroke, total cardiovascular disease, noncardiovascular disease/noncancer, and all causes for men and women, compared with 7 hours of sleep in both sexes. There was no association between sleep duration and cancer mortality in either sex.

Conclusions:

Both short and long sleep duration were associated with increased mortality from cardiovascular disease, noncardiovascular disease/noncancer, and all causes for both sexes, yielding a U-shaped relationship with total mortality with a nadir at 7 hours of sleep.

Citation:

Ikehara S; Iso H; Date C; Kikuchi S; Watanabe Y; Wada Y; Inaba Y; Tamakoshi A. Association of sleep duration with mortality from cardiovascular disease and other causes for Japanese men and women: the JACC study. SLEEP 2009;32(3):259–301.     

Sleep Duration and Cardiovascular Disease: Results from the National Health Interview Survey

Background:

Previous studies have shown that both short and long sleep durations are related to increased likelihood of diabetes and hypertension. However, the relation between sleep duration and cardiovascular disease (CVD) is not clear. We examined the hypothesis that compared with sleep duration of 7 hours, shorter and longer sleep durations are independently related to CVD.

Methods:

We conducted a cross-sectional study of 30,397 National Health Interview Survey 2005 participants ≥ 18 years of age (57.1% women). Sleep duration was categorized as ≤ 5 hours, 6 hours, 7 hours, 8 hours, and ≥ 9 hours. The main outcome of interest was the presence of any CVD (n = 2146), including myocardial infarction, angina, and stroke.

Results:

We found both short and long sleep durations to be independently associated with CVD, independent of age, sex, race-ethnicity, smoking, alcohol intake, body mass index, physical activity, diabetes mellitus, hypertension, and depression. Compared with a sleep duration of 7 h (referent), the multivariate odds ratio (95% confidence interval) of CVD was 2.20 (1.78, 2.71), 1.33 (1.13, 1.57), 1.23 (1.06, 1.41), and 1.57 (1.31, 1.89) for sleep duration ≤ 5 h, 6 h, 8 h, and ≥ 9 h. This association persisted in subgroup analyses by gender, race-ethnicity, and body mass index categories. Also, similar associations were observed when we examined myocardial infarction and stroke separately.

Conclusion:

Compared with sleep duration of 7 h, there was a positive association between both shorter and longer sleep durations and CVD in a representative sample of US adults. These results suggest that sleep duration may be an important marker of CVD.

Citation:

Sabanayagam C; Shankar A. Sleep duration and cardiovascular disease: results from the National Health Interview Survey. SLEEP 2010;33(8):1037-1042.     

Efficacy and Safety of 6-Month Nightly Ramelteon Administration in Adults with Chronic Primary Insomnia

Study Objectives:

Long-duration ( ≥ 6 months) polysomnographic studies of insomnia medications are lacking. This study evaluated the long-term efficacy of ramelteon, a selective MT₁/MT₂ melatonin-receptor agonist used for insomnia treatment.

Design:

Six-month, randomized, double-blind, placebo-controlled study.

Setting:

Forty-six investigative sites in the United States, Europe, Russia, and Australia.

Participants:

Four hundred fifty-one adults (age ≥ 18 years) with chronic primary insomnia.

Interventions:

Ramelteon, 8 mg, or placebo 30 minutes before bedtime nightly for 6 months.

Measurements:

Sleep was evaluated by polysomnography and morning questionnaires on the first 2 nights of Week 1; the last 2 nights of Months 1, 3, 5, and 6; and Nights 1 and 2 of the placebo run-out. Next-morning residual effects as well as adverse effects and vital signs were recorded at each visit. Rebound insomnia and withdrawal effects were evaluated during placebo run-out.

Results:

Over the 6 months of treatment, ramelteon consistently reduced latency to persistent sleep compared with baseline and with placebo; significant decreases were observed at Week 1 and Months 1, 3, 5, and 6 (P < 0.05). Ramelteon significantly reduced subjective sleep latency relative to placebo at Week 1, Month 1, and Month 5 (P < 0.05), with reductions nearing statistical significance at Months 3 and 6 (P ≤ 0.08). No significant next-morning residual effects were detected during ramelteon treatment. No withdrawal symptoms or rebound insomnia were detected after ramelteon discontinuation. Most adverse events were mild or moderate in severity.

Conclusions:

In adults with chronic insomnia, long-term ramelteon treatment consistently reduced sleep onset, with no next-morning residual effects or rebound insomnia or withdrawal symptoms upon discontinuation.

Citation:

Mayer G; Wang-Weigand S; Roth-Schechter B; Lehmann R; Staner C; Partinen M. Efficacy and safety of 6-month nightly ramelteon administration in adults with chronic primary insomnia. SLEEP 2009;32(3):351–360.     

Prospective Randomized Study of Patients with Insomnia and Mild Sleep Disordered Breathing

Background:

Patients with insomnia may present with mild and often unrecognized obstructive sleep apnea (OSA).

Objective:

To evaluate both subjective and objective outcomes of patients with complaints of insomnia and mild OSA who receive surgical treatment for OSA versus behavioral treatment with cognitive behavioral therapy for insomnia (CBT-I).

Methods:

Prospective study with crossover design of 30 patients with complaints of insomnia and mild OSA. Thirty subjects, matched for age and gender, were randomized with stratification to receive either CBT-I or surgical treatment of OSA as primary treatment. Patients were reassessed after completing the initial intervention and reassigned if agreeable to the alternative treatment option and assessed again on completion of both treatment arms. Outcome measures included clinical impression, Epworth Sleepiness Scale (ESS) score, Fatigue Severity Scale (FSS) score, and polysomnography (PSG) results.

Results:

Surgery resulted in greater improvements in total sleep time (TST), slow wave sleep and REM sleep duration, respiratory disturbance index, apnea-hypopnea index, minimum oxygen saturation, FSS, and ESS. CBT-I also improved TST and resulted in shorter sleep latency.

Conclusion:

Surgical intervention for the management of patients with complaints of insomnia and mild OSA demonstrated greater improvement in both subjective and objective outcome measures. Initial treatment of underlying OSA in patients with insomnia was more successful in improving insomnia than CBT-I alone. However CBT-I as initial treatment improved TST compared to baseline; following surgical intervention, it had the additional benefit of further increasing TST and helped to control sleep onset difficulties that may be related to conditioning due to unrecognized symptoms of mild OSA.

Citation:

Guilleminault C; Davis K; Huynh NT. Prospective randomized study of patients with insomnia and mild sleep disordered breathing. SLEEP 2008;31(11):1527–1533     

Actigraphy in the Assessment of Insomnia: A Quantitative Approach

Study Objective:

The lack of quantitative criteria for identifying insomnia using actigraphy represents an unresolved limit for the use of actigraphy in a clinical setting. The current study was conducted to evaluate the most efficient actigraphic parameter in the assessment of insomnia and to suggest preliminary quantitative actigraphic criteria (QAC).

Participants and Measurements:

Performing a retrospective study we recovered 408 actigraphic records from 3 sleep measure databases: 2 regarding insomnia patients (n = 126) and one normal sleepers (n = 282). We compared the 2 samples analyzing the following actigraphic sleep parameters: time in bed (TIB), sleep onset latency (SOL), total sleep time (TST), wake after sleep onset (WASO), sleep efficiency percentage (SE%), number of awakenings longer than 5 minutes (NA > 5) and mean motor activity (MA). Moreover, a linear discriminant function (LDF) was developed to identify and combine the most useful actigraphic sleep parameters to separate insomnia patients from normal sleepers. Using Youden index we calculated the preliminary QAC for each actigraphic sleep parameter and for LDF. Receiver operator characteristic (ROC) curves for classifying the accuracy of QAC were performed.

Results:

All sleep parameters recorded by actigraphy significantly differentiated the 2 groups, except TIB. An LDF analysis showed that the most useful combination of actigraphic sleep parameters to assess insomnia was TST, SOL, and NA > 5, which obtained the best ROC and the best balance between positive and negative predictive values compared to any single actigraphic parameter.

Conclusion:

Actigraphy provided a satisfactory objective measurement of sleep quality in insomnia patients. The combination of TST, SOL, and NA > 5 proved the best way to assess insomnia using actigraphy. Acknowledging that the lack of a technological standard and some methodological limitations prevent us generalizing our results, we recommend additional studies on larger populations using different actigraph models.

Citation:

Natale V; Plazzi G; Martoni M. Actigraphy In The Assessment Of Insomnia: A Quantitative Approach. SLEEP 2009;32(6):767–771.     

Sleep Disorders and their Association with Laboratory Pain Sensitivity in Temporomandibular Joint Disorder

Study Objectives:

We characterized sleep disorder rates in temporomandibular joint disorder (TMD) and evaluated possible associations between sleep disorders and laboratory measures of pain sensitivity.

Design:

Research diagnostic examinations were conducted, followed by two consecutive overnight polysomnographic studies with morning and evening assessments of pain threshold.

Setting:

Orofacial pain clinic and inpatient sleep research facility

Participants:

Fifty-three patients meeting research diagnostic criteria for myofascial TMD.

Interventions:

N/A

Measurements and Results:

We determined sleep disorder diagnostic rates and conducted algometric measures of pressure pain threshold on the masseter and forearm. Heat pain threshold was measured on the forearm; 75% met self-report criteria for sleep bruxism, but only 17% met PSG criteria for active sleep bruxism. Two or more sleep disorders were diagnosed in 43% of patients. Insomnia disorder (36%) and sleep apnea (28.4%) demonstrated the highest frequencies. Primary insomnia (PI) (26%) comprised the largest subcategory of insomnia. Even after controlling for multiple potential confounds, PI was associated with reduced mechanical and thermal pain thresholds at all sites (P < 0.05). Conversely, the respiratory disturbance index was associated with increased mechanical pain thresholds on the forearm (P < 0.05).

Conclusions:

High rates of PI and sleep apnea highlight the need to refer TMD patients complaining of sleep disturbance for polysomnographic evaluation. The association of PI and hyperalgesia at a non-orofacial site suggests that PI may be linked with central sensitivity and could play an etiologic role in idiopathic pain disorders. The association between sleep disordered breathing and hypoalgesia requires further study and may provide novel insight into the complex interactions between sleep and pain-regulatory processes.

Citation:

Smith MT; Wickwire EM; Grace EG; Edwards RR; Buenaver LF; Peterson S; Klick B; Haythornthwaite JA. Sleep disorders and their association with laboratory pain sensitivity in temporomandibular joint disorder. SLEEP 2009;32(6):779–790.     

Long Working Hours and Sleep Disturbances: The Whitehall II Prospective Cohort Study

Study Objective:

To examine whether exposure to long working hours predicts various forms of sleep disturbance; short sleep, difficulty falling asleep, frequent waking, early waking and waking without feeling refreshed.

Design:

Prospective study with 2 measurements of working hours (phase 3, 1991–1994 and phase 5, 1997–1999) and 2 measurements of subjective sleep disturbances (phase 5 and phase 7, 2002–2004).

Setting:

The Whitehall II study of British civil servants.

Participants:

Full time workers free of sleep disturbances at phase 5 and employed at phases 5 and 7 (n = 937–1594) or at phases 3, 5, and 7 (n = 886–1510).

Measurements and Results:

Working more than 55 hours a week, compared with working 35–40 hours a week, was related to incident sleep disturbances; demographics-adjusted odds ratio (95% CI) 1.98 (1.05, 3.76) for shortened sleeping hours, 3.68 (1.58, 8.58) for difficulty falling asleep; and 1.98 (1.04, 3.77) for waking without feeling refreshed. Repeat exposure to long working hours was associated with odds ratio 3.24 (1.45, 7.27) for shortened sleep, 6.66 (2.64, 16.83) for difficulty falling asleep, and 2.23 (1.16, 4.31) for early morning awakenings. Some associations were attenuated after adjustment for other risk factors. To a great extent, similar results were obtained using working hours as a continuous variable. Imputation of missing values supported the findings on shortened sleep and difficulty in falling asleep.

Conclusion:

Working long hours appears to be a risk factor for the development of shortened sleeping hours and difficulty falling asleep.

Citation:

Virtanen M; Ferrie JE; Vahtera J; Elovainio M; Singh-Manoux A; Marmot MG; Kivimäki M. Long working hours and sleep disturbances: the whitehall II prospective cohort study. SLEEP 2009;32(6):737–745.     

Sleep and Rhythm Consequences of a Genetically Induced Loss of Serotonin

Background:

A genetic deficiency in sepiapterin reductase leads to a combined deficit of serotonin and dopamine. The motor phenotype is characterized by a dopa–responsive fluctuating generalized dystonia–parkinsonism. The non–motor symptoms are poorly recognized. In particular, the effects of brain serotonin deficiency on sleep have not been thoroughly studied.

Objective:

We examine the sleep, sleep–wake rhythms, CSF neurotransmitters, and melatonin profile in a patient with sepiapterin reductase deficiency.

Patient:

The patient was a 28–year–old man with fluctuating generalized dystonia–parkinsonism caused by sepiapterin reductase deficiency.

Methods:

A sleep interview, wrist actigraphy, sleep log over 14 days, 48–h continuous sleep and core temperature monitoring, and measurement of CSF neurotransmitters and circadian serum melatonin and cortisol levels before and after treatment with 5–hydroxytryptophan (the precursor of serotonin) and levodopa were performed.

Results:

Before treatment, the patient had mild hypersomnia with long sleep time (704 min), ultradian sleep–wake rhythm (sleep occurred every 11.8 ± 5.3 h), organic hyperphagia, attention/executive dysfunction, and no depression. The serotonin metabolism in the CSF was reduced, and the serum melatonin profile was flat, while cortisol and core temperature profiles were normal. Supplementation with 5–hydroxytryptophan, but not with levodopa, normalized serotonin metabolism in the CSF, reduced sleep time to 540 min, normalized the eating disorder and the melatonin profile, restored a circadian sleep–wake rhythm (sleep occurred every 24±1.7 h, P < 0.0001), and improved cognition.

Conclusion:

In this unique genetic paradigm, the melatonin deficiency (caused by a lack of its substrate, serotonin) may cause the ultradian sleep–wake rhythm.

Citation:

Leu–Semenescu S; Arnulf I; Dicaix C; Moussa F; Clot F; Boniol C; Touitou Y; Levy R; Vidailhet M; Roze E. Sleep and rhythm consequences of a genetically induced loss of serotonin. SLEEP 2010;33(3):307–314.     

Interpreting Wrist Actigraphic Indices of Sleep in Epidemiologic Studies of the Elderly: The Study of Osteoporotic Fractures

Introduction:

Although wrist actigraphy-derived sleep indices correlate with adverse health outcomes, it is unclear whether these indices identify specific sleep disorders.

Methods:

Overnight polysomnography and ≥ three 24-h periods of wrist actigraphy were performed in the Study of Osteoporotic Fractures (SOF) (n = 455, age: 73–96 y). Actigraphy identified those with reduced sleep efficiency (SE, < 70%) and decreased sleep duration (≤ 5 h). Sleep disorders considered were: (1) sleep-disordered breathing (SDB): respiratory disturbance index ≥ 15 and (2) periodic limb movement disorder (PLMD): periodic limb movement-arousal index ≥ 5. Multivariable logistic regression analyses modeled each sleep disorder as the dependent variable with wrist actigraphy measures, age, race, medication use, depression, body mass index, activity, mental status, and comorbidity as independent variables.

Results:

In multivariable models, poor SE derived from wrist actigraphy was associated with 2.4-fold higher odds of SDB (OR = 2.43, 95% CI: 1.43–4.14) and PLMD (OR = 2.36, 95% CI: 1.34–4.15). Reduced sleep duration was associated with 3.2-fold higher odds of SDB (OR = 3.18, 95% CI: 1.51–6.68), and a 3.8-fold higher odds of PLMD (OR = 3.77, 95% CI: 1.78–17.95).

Conclusions:

In elderly women, wrist actigraphy-ascertained reduced SE and sleep duration are associated with objective measures of SDB and PLMD. Thus, although not able to discriminate between the different sleep disorders, variations in wrist actigraphy measures collected in epidemiologic studies may identify individuals at higher risk of SDB or PLMD.

Citation:

Mehra R; Stone KL; Ancoli-Israel S; Litwack-Harrison S; Ensrud KE; Redline S. Interpreting wrist actigraphic indices of sleep in epidemiologic studies of the elderly: the study of osteoporotic fractures. SLEEP 2008;31(11):1569–1576.     

Sleep Stage Dynamics Differ Between Children With and Without Obstructive Sleep Apnea

Study Objectives:

Analysis of sleep dynamics—distributions of contiguous sleep and sleep stage durations—reveal exponential distributions and potential clinical utility in adults. We sought to examine these polysomnographic variables for the first time in children, and in the context of childhood sleep disordered breathing (SDB).

Design and Setting:

Analysis of polysomnographic data available from the Washtenaw County Adenotonsillectomy Cohort.

Participants:

Selected subjects were 48 children aged 5–12 years with SDB (pediatric apnea/hypopnea index ≥ 1.5) who were scheduled for adenotonsillectomy and 20 control subjects of similar ages without SDB. Subjects were studied at enrollment and again one year later in almost all cases.

Results:

Durations of sleep and specific sleep stage bouts generally followed exponential distributions. At baseline, the number of sleep stage changes, proportion of total sleep time occupied by stage 1 sleep, proportion stage 2 sleep, mean stage 2 duration, and mean stage REM duration each distinguished subjects with and without SDB (P < 0.05), but only mean stage 2 duration did so independently after accounting for the other variables (P = 0.03). At one-year follow-up, changes in total sleep time, mean stage 2 duration, and mean stage REM duration distinguished SDB from control subjects, but again only changes in mean stage 2 duration did so independently (P = 0.01)

Conclusions:

Durations of uninterrupted sleep and specific sleep stages appear to follow exponential distributions in children with or without SDB. Parameters that describe these distributions—particularly mean duration of stage 2 sleep periods—may provide useful additions to standard sleep stage analyses.

Citation:

Chervin RD; Fetterolf JL; Ruzicka DL; Thelen BJ; Burns JW. Sleep stage dynamics differ between children with and without obstructive sleep apnea. SLEEP 2009;32(10):1325-1332.     

Nighttime Blood Pressure in Normotensive Subjects With Chronic Insomnia: Implications for Cardiovascular Risk

Objective:

To assess as whether insomniacs have higher nighttime blood pressure (BP) and a blunted day-to-night BP reduction, recognized markers of increased risk of cardiovascular morbidity and mortality.

Design:

Prospective case-control study.

Setting:

University hospital-based sleep research laboratory.

Participants:

Thirteen normotensive subjects with chronic primary insomnia (9 women, 42 ± 7 y) and 13 sex- and age-matched good sleepers.

Measurements and results:

Subjects underwent 2-week sleep diary and 3 sleep studies to provide subjective and objective sleep variables, and 24-h beat-to-beat BP recording to provide daytime, night-time and day-to-night BP changes ([nighttime-daytime]/daytime)*100) (BP dipping). Spectral analysis of the electroencephalogram (EEG) was also performed during sleep of night 3 to assess EEG activity in the β frequency (16-32 Hz), a measure of brain cortical activation. Nighttime SBP was higher (111 ± 15 vs 102 ± 12 mm Hg, P < 0.01) and day-to-night SBP dipping was lower (−8% ± 6% vs −15% ± 5%, P < 0.01) in insomniacs than good sleepers. Insomniacs also had higher activity in EEG β frequency (P < 0.05). Higher nighttime SBP and smaller SBP dipping were independently associated with increased EEG β activity (P < 0.05).

Conclusions:

Higher nighttime SBP and blunted day-to-night SBP dipping are present in normotensive subjects with chronic insomnia and are associated with a hyperactivity of the central nervous system during sleep. An altered BP profile in insomniacs could be one mechanism implicated in the link between insomnia and cardiovascular morbidity and mortality documented in epidemiological studies.

Citation:

Lanfranchi PA; Pennestri MH; Fradette L; Dumont M; Morin CM; Montplaisir J. Nighttime blood pressure in normotensive subjects with chronic insomnia: implications for cardiovascular risk. SLEEP 2009;32(6):760-766.     

Associations Between Sleep Duration Patterns and Overweight/Obesity at Age 6

Objective:

To investigate whether longitudinal sleep duration patterns during early childhood is a risk factor of overweight or obesity at school entry while controlling for a variety of obesogenic environmental factors.

Design, Setting, and Participants:

This is a prospective cohort study (March–December 1998 to December 2004) of a representative sample of infants born in 1997–1998 in the Canadian province of Quebec. Body mass index (BMI) was measured at ages 2.5 and 6 years. Sleep duration was reported yearly from 2.5 to 6 years of age by their mothers. Prenatal, postnatal (5 and 29 months), and lifestyle (6 y) potentially confounding factors for excess weight were assessed by interviews, questionnaires and hospital records. A group-based semiparametric mixture model was used to estimate developmental patterns of sleep duration. The relationship between sleep duration patterns and BMI was tested using multivariate logistic regression models to control for potentially confounding factors on 1138 children.

Results:

Four sleep duration patterns were identified: short persistent (5.2%), short increasing (4.7%), 10-hour persistent (50.7%), and 11-hour persistent (39.4%). After controlling for potentially confounding factors, the risk for overweight or obesity was almost 4.2 times higher for short persistent sleepers (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.6 to 11.1; P = 0.003) than for 11-hour persistent sleepers.

Conclusions:

Persistently short sleep duration (<10 h) during early childhood significantly increases the risk of excess weight or obesity in childhood, and appears to be independent of other obesogenic factors.

Citation:

Touchette E; Petit D; Tremblay RE; Boivin M; Falissard B; Genolini C; Montplaisir JY. Associations between sleep duration patterns and overweight/obesity at age 6. SLEEP 2008;31(11):1507–1514.     

The Prevalence of Short Sleep Duration by Industry and Occupation in the National Health Interview Survey

Study Objectives:

To explore whether employment in industries likely to have non-standard work schedules (e.g., manufacturing and service) and occupations with long work-weeks (e.g., managerial/ professional, sales, and transportation) is associated with an increased risk of short sleep duration.

Design:

Cross-sectional epidemiologic survey.

Setting:

Household-based face-to-face survey of civilian, non-institutionalized US residents.

Participants:

Sample adults interviewed for the National Health Interview Survey in 1985 or 1990 (N = 74,734) or between 2004 and 2007 (N = 110,422). Most analyses focused on civilian employed workers interviewed between 2004 and 2007 (N = 66,099).

Interventions:

N/A

Measurements and Results:

The weighted prevalence of self-reported short sleep duration, defined as ≤6 h per day, among civilian employed workers from 2004-2007 was 29.9%. Among industry categories, the prevalence of short sleep duration was greatest for management of companies and enterprises (40.5%), followed by transportation/warehousing (37.1%) and manufacturing (34.8%). Occupational categories with the highest prevalence included production occupations in the transportation/warehousing industry, and installation, maintenance, and repair occupations in both the transportation/warehousing industry and the manufacturing industry. In the combined sample from 1985 and 1990, 24.2% of workers reported short sleep duration; the prevalence of short sleep duration was significantly lower during this earlier time period compared to 2004–2007 for 7 of 8 industrial sectors.

Conclusions:

Self-reported short sleep duration among US workers varies by industry and occupation, and has increased over the past two decades. These findings suggest the need for further exploration of the relationship between work and sleep, and development of targeted interventions for specific industry/occupation groups.

Citation:

Luckhaupt SE; Tak S; Calvert GM. The prevalence of short sleep duration by industry and occupation in the National Health Interview Survey. SLEEP 2010;33(2):149-159     

Association of Short Sleep Duration with Weight Gain and Obesity at 1-Year Follow-Up: A Large-Scale Prospective Study

Study Objectives:

To investigate the association between short sleep duration and elevated body mass index (BMI) and obesity in a large sample of Japanese adults over a short period

Design:

Prospective design with baseline in 2006 and 1-year follow-up

Setting:

Workplaces of an electric power company in Japan

Participants:

35,247 company employees (31,477 men, 3,770 women) distributed throughout Japan

Measurements and Results:

Measured weight and height and self-reported sleep duration were obtained at annual health checkup in 2006 and 2007. Weight change was defined as the difference in body mass index (BMI) between the baseline and 1 year later. Relative to the reference category (sleep duration 7-8 h), short sleep duration (< 5 and 5-6 h) and long sleep duration ≥ 9 h were associated with an increased risk of weight gain among men after adjustment for covariates. Of the non-obese (BMI < 25) men at baseline, 5.8% became obese (BMI ≥ 25) 1 year later. Higher incidence of obesity was observed among the groups with shorter sleep duration. Adjusted odds ratios for the development of obesity were 1.91 (95%CI 1.36, 2.67) and 1.50 (95%CI 1.24, 1.80) in men who slept < 5 and 5-6 h, respectively. No significant association between sleep duration and weight gain or obesity was found for women.

Conclusions:

Short sleep duration was associated with weight gain and the development of obesity over 1 year in men, but not in women.

Citation:

Watanabe M; Kikuchi H; Tanaka T; Takahashi M. Association of short sleep duration with weight gain and obesity at 1-year follow-up: a large-scale prospective study. SLEEP 2010;33(2):161-167.     

Sleep Duration and Biomarkers of Inflammation

Introduction:

Extremes of sleep duration have been associated with adverse health outcomes. The mechanism is unclear but may be related to increased inflammation. We sought to assess the association between sleep duration and inflammatory biomarkers.

Methods:

A total of 614 individuals from the Cleveland Family Study completed questionnaires about sleep habits and underwent polysomnography. A morning fasting blood sample was assayed for 5 inflammatory cytokines.

Results:

In this cohort, mean (SD) habitual sleep duration based on self-report was 7.6 (1.6) h and mean sleep duration by polysomnography (PSG) on the night prior to blood sampling was 6.2 (1.3) h. After adjusting for obesity and apnea severity, each additional hour of habitual sleep duration was associated with an 8% increase in C-reactive protein (CRP) levels (P = 0.004) and 7% increase in interleukin-6 (IL-6) levels (P = 0.0003). These associations were independent of self-reported sleepiness. In contrast, PSG sleep duration was inversely associated with tumor necrosis factor alpha (TNFα) levels. For each hour reduction in sleep, TNFα levels increased by 8% on average (P = 0.02). Sleep duration was not associated with IL-1 or IL-10.

Conclusions:

Increases in habitual sleep durations are associated with elevations in CRP and IL-6 while reduced PSG sleep duration is associated with elevated TNFα levels. Activation of pro-inflammatory pathways may represent a mechanism by which extreme sleep habits affect health.

Citation:

Patel SR; Zhu X; Storfer-Isser A; Mehra R; Jenny NS; Tracy R; Redline S. Sleep duration and biomarkers of inflammation. SLEEP 2009;32(2):200–204.     

Sleep Duration and Five-Year Abdominal Fat Accumulation in a Minority Cohort:The IRAS Family Study

Study Objective:

To study 5-year change in computed tomography (CT)-derived visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) associated with sleep duration in 2 minority groups.

Design:

Longitudinal epidemiologic study.

Setting:

Three US communities.

Participants:

African Americans (N = 332) and Hispanic Americans (N = 775), aged 18-81 years, participating in the IRAS Family Study.

Interventions:

none

Measurements and Results:

Abdominal CT scans and BMI obtained at a 5-year interval. Sleep duration was assessed by questionnaire at baseline and categorized as ≤5 h, 6-7 h, and ≥8 h. Generalized estimating equations assessed the association between sleep duration and 5-year fat accumulation with adjustment for age, race, gender, study site, baseline fat measure, physical activity, total calories, smoking status, and education. Age interacted with sleep duration to predict change in fat measures (P < 0.01). In those younger than 40 years, ≤5 h of sleep was related to a greater accumulation of BMI (1.8 kg/m², P < 0.001), SAT (42 cm², P < 0.0001), and VAT (13 cm², P > 0.01), compared to sleep duration between 6 and 7 h. Eight hours or more of sleep was also significantly related to a greater accumulation of BMI (0.8 kg/m², P < 0.001), SAT (20 cm², P < 0.01) and VAT (6 cm², P < 0.05) compared to sleep duration between 6 and 7 h. No significant relationship existed between sleep duration and fat depot change in participants older than 40 years old.

Conclusions:

In this minority cohort, extremes of sleep duration are related to increases in BMI, SAT, and VAT in persons younger than 40 years old.

Citation:

Hairston KG; Bryer-Ash M; Norris JM; Haffner S; Bowden DW; Wagenknecht LE. Sleep duration and five-year abdominal fat accumulation in a minority cohort: the IRAS family study.     

Idiopathic Hypersomnia with and without Long Sleep Time: A Controlled Series of 75 Patients

Objective:

To characterize the clinical, psychological, and sleep pattern of idiopathic hypersomnia with and without long sleep time, and provide normative values for 24-hour polysomnography.

Setting:

University Hospital

Design:

Controlled, prospective cohort

Participants:

75 consecutive patients (aged 34 ± 12 y) with idiopathic hypersomnia and 30 healthy matched controls.

Intervention:

Patients and controls underwent during 48 hours a face-to face interview, questionnaires, human leukocyte antigen genotype, a night polysomnography and multiple sleep latency test (MSLT), followed by 24-h ad libitum sleep monitoring.

Results:

Hypersomniacs had more fatigue, higher anxiety and depression scores, and more frequent hypnagogic hallucinations (24%), sleep paralysis (28%), sleep drunkenness (36%), and unrefreshing naps (46%) than controls. They were more frequently evening types. DQB1*0602 genotype was similarly found in hypersomniacs (24.2%) and controls (19.2%). Hypersomniacs had more frequent slow wave sleep after 06:00 than controls. During 24-h polysomnography, the 95% confidence interval for total sleep time was 493–558 min in controls, versus 672–718 min in hypersomniacs. There were 40 hypersomniacs with and 35 hypersomniacs without long ( > 600 min) sleep time. The hypersomniacs with long sleep time were younger (29 ± 10 vs 40 ± 13 y, P = 0.0002), slimmer (body mass index: 26 ± 5 vs 23 ± 4 kg/m²; P = 0.005), and had lower Horne-Ostberg scores and higher sleep efficiencies than those without long sleep time. MSLT latencies were normal ( > 8 min) in 71% hypersomniacs with long sleep time.

Conclusions:

Hypersomnia, especially with long sleep time, is frequently associated with evening chronotype and young age. It is inadequately diagnosed using MSLT.

Citation:

Vernet C; Arnulf I. Idiopathic Hypersomnia with and without Long Sleep Time: A Controlled Series of 75 Patients. SLEEP 2009;32(6):753-759.