Th2 shift in mononeuritis multiplex and increase of Th2 cells in chronic inflammatory demyelinating polyneuropathy: an intracellular cytokine analysis.

To elucidate the T helper 1 (Th1)/T helper 2 (Th2) balance in various inflammatory neuropathies, we measured the ratio of intracellular interferon-gamma (IFN-gamma)-positive to IL-4-positive cells (intracellular IFN-gamma/IL-4 ratio) by flow cytometry in peripheral blood CD4(+) T cells of 14 patients with mononeuritis multiplex (MNM), 12 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 10 patients with Guillain-Barré syndrome (GBS), 23 patients with neurodegenerative disorders and 36 healthy controls by intracellular labeling. The patients with MNM showed a significantly lower intracellular IFN-gamma/IL-4 ratio (P<0.05) and higher IL-4(+)/IFN-gamma(-) cell percentages (P<0.05) than the controls. The increase of IL-4(+)/IFN-gamma(-) cell percentages was especially prominent in MNM of unknown etiology (P<0.005). The patients with CIDP also showed significantly higher IL-4(+)/IFN-gamma(-) cell percentages (P<0.05) than the controls. The IL-4(+)/IFN-gamma(-) cell percentages were increased in some patients with GBS, but the difference was not significant compared with the controls. Thus, our results suggest that a Th2 shift is a characteristic of MNM and may play an important role in the development of the disease.     

Th1, Th2 and Th3 cytokine alteration in schizophrenia

BACKGROUND: Several studies have shown that there is an imbalance between T helper 1 (Th1) cytokines and T helper 2 (Th2) cytokines in patients with schizophrenia. The T helper 3 (Th3) cytokine, transforming growth factor beta-1 (TGF-beta1), has been shown to suppress the production of Th1 cytokines. Therefore it is hypothesized that it may play a role in schizophrenia by suppressing overactive Th1 system. METHODS: We recruited 88 schizophrenic patients and 88 matched controls. The basal plasma concentrations of IFN-gamma (Th1), IL-4 (Th2) and TGF-beta1 (Th3) were studied at the time the patients were admitted to the hospital and following 8 weeks of treatment with antipsychotics. RESULTS: The detection rate of plasma IFN-gamma and basal plasma TGF-beta1 level were significantly higher in schizophrenic patients than in controls whereas detection rate of plasma IL-4 was lower in patients. The ratio of Th1/Th2 cytokines (IFN-gamma/IL-4) was higher in schizophrenic patients. Following the neuroleptic treatment, the IFNgamma and TGF-beta1 levels returned to control values, and IL-4 concentration rose above the control value. CONCLUSION: Schizophrenic patients showed higher Th1/Th2 ratio which is attenuated by effective neuroleptic treatment. It is possible that TGF-beta1 plays a role in reducing the activity of Th1 cytokine.     

DSM-IV psychiatric comorbidity according to symptoms of insomnia: a nationwide sample of Korean adults

Purpose

The diagnosis of insomnia is based on the presence of four different symptoms: difficulty in initiating sleep (DIS), difficulty in maintaining sleep (DMS), early morning awakening (EMA), and non-restorative sleep (NRS). This study investigated the differences in sociodemographic correlates and psychiatric comorbidity between the four symptoms of insomnia in the general population of South Korea.

Methods

A sample of the population aged 18–64 (N?=?6,510) was questioned using a face-to-face interview. Insomnia was defined as having at least one of the four following symptoms three or more times per week: DIS, DMS, EMA, and NRS. Psychiatric disorders were evaluated using the Korean version of Composite International Diagnostic Interview. Logistic regression analysis was used to test each of the sleep outcomes (DIS, DMS, EMA, or NRS) for an association with sociodemographic and clinical variables.

Results

The prevalence of DIS, DMS, EMA, and NRS were 7.9?% (95?% CI 6.6–9.5?%), 7.9?% (95?% CI 6.5–9.6?%), 4.9?% (95?% CI 3.9–6.0?%), and 14.8?% (95?% CI 12.6–17.4?%), respectively. The overall prevalence of insomnia was 19.0?% (95?% CI 16.1–22.2?%). Being separated, divorced, or widowed, being single, having a part-time job, having a psychiatric illness, and having a physical illness were all significantly related to insomnia. Older age also increased the risk of DMS and EMA, and younger age was a risk factor for NRS. The presence of most psychiatric disorders was significantly related to insomnia. However, the relationship between the psychiatric illness and each insomnia symptom varied and was dependent on the insomnia symptom.

Conclusions

Most psychiatric disorders were significantly associated with each insomnia symptom in different ways. Differences in sociodemographic and clinical correlates between the four insomnia symptoms implied the heterogeneous characteristics of insomnia as defined by the current diagnostic criteria.     

Monocytic, Th1 and th2 cytokine alterations in the pathophysiology of schizophrenia

A growing body of evidence suggests that changes in the serum levels and cellular production of various cytokines are associated with the immunological abnormalities of schizophrenia. Several studies have examined alterations in T helper type 1 (Th1) and T helper type 2 (Th2) cytokines in schizophrenia. We explored monocytic, Th1 and Th2 cytokines in 43 schizophrenia patients and 50 normal controls. The mitogen-induced production of tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), IL-4, gamma-interferon (IFN-gamma) and IL-2 was measured with enzyme-linked immunosorbent assays before and after antipsychotic treatment. IL-6 and TNF-alpha production by schizophrenic patients was significantly higher than by normal controls, while IL-2, IL-4 and IFN-gamma production was significantly lower in schizophrenic patients. After 6 weeks of antipsychotic treatment, IL-6 and TNF-alpha production was significantly decreased, while IL-4, IFN-gamma and IL-2 productions were not significantly changed. Our results suggest that increased monocytic cytokines and decreased Th1 and Th2 cytokines may be associated with the immunopathogenesis of acute psychotic schizophrenia, and that antipsychotics may play an important role in immune response by decreasing elevated monocytic cytokines.     

Prevalence and correlates of insomnia in the Swedish population aged 19-75 years

ObjectiveTo assess the prevalence of insomnia symptoms, their associated factors and daytime symptoms in the general population of Sweden.MethodsThis is a cross-sectional postal survey performed in the general population of Sweden aged between 19 and 75 years (6 million inhabitants). A total of 1209 out of 1705 randomly selected participants from the National Register of the Total Population completed the questionnaire. The participation rate was 71.3%. Participants filled out a paper–pencil questionnaire composed of 157 items covering sociodemographic characteristics, sleeping habits and environment, sleep quality and sleep symptoms, and health status.ResultsWe found 32.1% (95% confidence interval: 29.5–34.8%) of the sample reported having difficulty initiating (DIS) or maintaining sleep (DMS) or non-restorative sleep accompanied with sufficient sleep (NRS) at least 4 nights per week: 6.3% of the sample had DIS, 14.5% had DMS and 18.0% had NRS. Results from logistic regressions showed that restless legs symptoms, breathing pauses during sleep and depressive or anxious mood were associated with DIS and DMS but not NRS. Living in an urban area (OR:2.0) and drinking alcohol daily (OR:4.6) were associated only with NRS. Daytime symptoms were reported by over 75% of subjects with insomnia symptoms. DIS, DMS and NRS were associated with daytime fatigue but not excessive sleepiness as measured by the Epworth scale. DIS was associated with the use of sleeping pills or natural sleeping aid compounds in multivariate models.ConclusionsInsomnia symptoms occurring at least 4 nights per week are frequent in Sweden, affecting about a third of the population. Subjects with NRS have a distinctly different profile than those with DIS or DMS, which suggests different etiological causes for this symptom.     

Sleep associated regulation of T helper 1/T helper 2 cytokine balance in humans

Recent human studies suggested a supportive influence of regular nocturnal sleep on immune responses to experimental infection (vaccination). We hypothesized here that sleep could ease such responses by shifting the balance between T helper 1 (Th1) and T helper 2 (Th2) cytokine activity towards Th1 dominance thereby favoring cellular over humoral responses to infection. We compared the Th1/Th2 cytokine balance in 14 healthy men during regular nocturnal sleep (between 23:00 and 07:00 h) and while remaining awake during the same nocturnal interval, in a within-subject cross-over design. Blood was collected every 2 h. Production of T cell derived cytokines--interferon-gamma (IFN-gamma), interleukin-2 (IL-2), interleukin-4 (IL-4), and tumor necrosis factor-alpha (TNF-alpha)--was measured at the single cell level using multiparametric flow cytometry. Also, several immunoactive hormones--prolactin, growth hormone (GH), thyroid stimulating hormone (TSH), cortisol, and melatonin--were measured, the release of which is known to be regulated by sleep. Compared with wakefulness, early nocturnal sleep induced a shift in the Th1/Th2 cytokine balance towards increased Th1 activity, as indicated by an increased (p <.05) ratio of IFN-gamma/IL-4 producing T helper cells. However, the Th1 shift was only of moderate size and replaced by Th2 dominance during late sleep (p <.05). It could be mediated via release of prolactin and GH which both were distinctly increased during sleep (p <.001). Though unexpected, the most pronounced effect of sleep on T cell cytokine production was a robust decrease in TNF-alpha producing CD8+ cells probably reflecting increased extravasation of cytotoxic effector and memory T cells.     

Psychological factors and insomnia among male civil servants in Japan

OBJECTIVE: This study aims at assessing the relative impact of psychological factors on insomnia among daytime workers. BACKGROUND: Insomnia affects 5-45% of non-shift workers, making it a serious public health concern. METHODS: The study population was 3435 male civil servants aged 35 years and over. A self-administered questionnaire survey was conducted in 2002. Annual health examination data compiled in the same year were also obtained. Insomnia was assessed in three domains: difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), and poor quality of sleep (PQS). Association of each factor with insomnia was examined by age-adjusted logistic regression models. Factors significantly associated with insomnia in age-adjusted analyses were entered in the stepwise logistic regression models to test the relative impact of each factor. RESULTS: Prevalence of insomnia was 12.3% (DIS), 20.4% (DMS), and 32% (PQS). In stepwise logistic models, high perceived stress was associated with all types of insomnia with odds ratios (95% confidence interval) of 2.27 (1.58-3.26), 2.15 (1.57-2.95), and 2.96 (2.19-3.99), for DIS, DMS, and PQS, respectively. Poor psychological well-being or not having confidants was also associated with insomnia. Somatic conditions such as illnesses or history of hospitalization were related to DIS and DMS. CONCLUSIONS: Psychological factors were strongly associated with DIS and PQS after controlling for possible confounders. In dealing with insomnia, such factors must not be neglected.     

Prevalence of insomnia symptoms: results from an urban district in Ankara,Turkey

Objective. Characteristics of insomnia symptoms in Turkey are not well established. The goal of this study was to determine the prevalence of insomnia and related symptoms in an urban district of Turkey. Method. The study was carried out in Ankara, in an urban district with a population of 2665. Out of the 1332 people in the sample, 1034 in the 15–65 age range were included in the study. Interviews were conducted according to the “Sleep Disorders Assessment Questionnaire” developed by the researchers. The Insomnia Severity Index (ISI) was also given to the subjects with a sleep problem to measure the subjective quality and quantity of insomnia symptoms. Results and conclusion. A total of 29.4% of all participants reported a sleep problem, out of which 23.7% defined one or more of the insomnia symptoms which included difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), early morning awakening (EMA), non-restorative sleep (NRS) and sleep deprivation (SD). Insomnia risk was found to be significantly increased with age, female sex, smoking and chronic medical illness. A total of 75.9% of participants who reported insomnia symptoms did not seek medical help for their complaint. According to the ISI, among the subjects with insomnia symptoms, 79 (32.2%) had subthreshold insomnia, 43 (17.6%) had clinical insomnia, 12 (4.9%) had severe clinical insomnia, while 88 (35.9%) did not score in the range indicating insomnia. The findings are discussed in the light of previous research and in relation to sociocultural factors emphasizing the need for public education on sleep disorders as medical conditions.     

Increased nocturnal interleukin-6 excretion in patients with primary insomnia: a pilot study

The aim of the present study was to investigate whether there is a difference in evening/nocturnal interleukin-6 (IL-6) serum excretion in patients with primary insomnia compared to controls. We hypothesized that in insomniac patients, the excretion of evening/nocturnal IL-6 is enhanced, like observed in aged adults and after sleep deprivation in healthy subjects. We studied IL-6 serum concentrations in 11 patients (two males and nine females) with primary insomnia and 11 age and gender-matched healthy controls. Sleep was monitored polysomnographically for three consecutive nights. The measurement of IL-6 (from 19:00 h to 09:00 h) in 2-h intervals were performed prior to and during the last laboratory night. Polysomnographically determined sleep parameters and subjective ratings of sleep demonstrated clear-cut impairments of sleep in the insomniac group. Nocturnal IL-6 secretion was significantly increased (p<.05) in insomniac patients for the whole measurement period (mean area under the curve+/-SD: 27.94+/-14.15 pg/ml x 2h) compared to controls (16.70+/-7.64 pg/ml x 2h). Total IL-6 secretion correlated inversely with subjectively perceived sleep quality and amount of slow wave sleep in the insomniac patients. Amount of Wake Time correlated positively with IL-6 excretion in insomniacs. The results of the present study demonstrate significantly increased nocturnal IL-6 secretion in insomniacs. It might be speculated that chronic primary insomnia with polysomnographically documented sleep impairments activates the production of IL-6 analogous to sleep deprivation studies in healthy subjects. This might also implicate a higher risk for inflammatory and cardiovascular diseases in patients with chronic insomnia.     

Melatonin modulation of lymphocyte proliferation and Th1/Th2 cytokine expression.

Melatonin is hypothesized to play a role in neuroimmunomodulation. This study investigated the in vitro effects of melatonin (10(-12) - 10(-6) M) on human peripheral blood mononuclear cell (PBMC) proliferation and T helper type 1 and T helper type 2 (Th1/Th2) cytokine expression. In vitro doses of melatonin significantly increased PBMC proliferation (p<0.05) and decreased IL-10 production in culture supernatants (p<0.05). However, there was no effect of melatonin on the stimulated production of IFN-gamma or on the intracellular accumulation of the activation antigen CD69, IFN-gamma, or IL-10 as measured by flow cytometry. These data support the notion that physiologic doses of melatonin increase lymphocyte proliferation possibly due to decreases in production of the inhibitory cytokine IL-10.     

Role of hormone-controlled Th1- and Th2-type cytokines in successful pregnancy

Development of CD4+ helper T (Th) cells into type 1 (Th1) or type 2 (Th2) effectors, as characterized by their opposite pattern of cytokine production, can be influenced by several factors, including hormones. Progesterone promotes the production of IL-4 and IL-5, whereas relaxin promotes the production of IFN-gamma by T cells. Leukemia inhibitory factor (LIF), essential for embryo implantation, is up-regulated by IL-4 and progesterone. Moreover, the production of LIF and/or Th2 cytokines by decidual T cells contributes to the maintenance of pregnancy. Our results suggest that relaxin and progesterone may contribute to the regulation of the immune homeostasis during pregnancy.     

The stimulus control paradigm in sleep-onset insomia: A multimethod assessment

Three studies were conducted to assess a stimulus control conceptualization of sleep-onset insomia. In the first study, eight sleep-onset insomniac and ten noninsomniac subjects were interviewed about their sleep patterns and presleep behaviors. Each subject then spent five nights in a sleep laboratory while standard psychophysiological measures were recorded along with subjective report of sleep-onset latency. The second study was a replication of the first using seven sleep-onset insomniac and eight noninsomniac subjects. In both studies, there were nonsignificant differences between insomniac and noninsomniac groups on self-reported frequency of sleep-incompatible behaviors, nap frequency or location, or variability in sleep habits. There were also nonsignificant relationships between these variables and laboratory measures of sleep-onset latency. In the third study, 23 insomniac and noninsomniac subjects self-monitored time spent in sleep-incompatible behaviors and sleep-onset latencies at home for 14 consecutive nights. There were no significant relationships among these variables. The results of all three studies are generally inconsistent with a stimulus control paradigm of sleep-onset insomia and alternative explanations for the effectiveness of stimulus control treatments must be considered.     

Lifestyles and sleep disorders among the Japanese adult population

To clarify the effects of daily stress, habitual exercise, drinking and smoking on the prevalence of sleep disorders, we selected 4000 residents (> or =20 years) in Japan by stratified random sampling and carried out structured interviews (response rate 75.8%). Frequencies of sleep disorders (difficulty initiating sleep: DIS; difficulty maintaining sleep: DMS; early morning awakening and hypnotic medication use) were treated as dependent variables. Significant effects of stress were prevalent in all sleep disorders. Habitual exercise had significant negative association with DIS and DMS. Drinking and smoking did not affect sleep disorders.     

Characteristics of insomnia in a primary care setting: EQUINOX survey of 5293 insomniacs from 10 countries

ObjectiveTo describe the characteristics of insomnia in primary care physicians’ (PCPs’) practices in 10 countries and to understand how the difficulty of maintaining sleep (DMS) was or was not associated with other insomnia symptoms such as difficulty initiating sleep (DIS), early morning awakenings (EMA) or nonrestorative sleep (NRS) in PCPs patients with insomnia.MethodsInternational, noninterventional, cross-sectional, observational survey conducted in a primary care setting in subjects complaining of sleep disturbances in 10 countries. A questionnaire based on DSM-IV and ICSD criteria was administered.ResultsThirteen thousand one hundred twenty-four subjects were enrolled by 647 physicians; 5293 of them (32.6%) had insomnia and were surveyed. The population was predominantly female (63.9%) with a mean age of 47.8 ± 15.3 years; 39.9% of these patients have already been treated for sleep difficulties. Combination of all types of insomnia symptoms (DIS + DMS + EMA + NRS) was the most frequently reported combination (38.6% of the subjects), while the percentage of subjects presenting with only one type of insomnia symptom (DIS, DMS, EMA or NRS) was very low: 3%, 1.8%, 0.9% and 1.4% respectively. DMS was on average the most commonly reported insomnia symptom (80.2%). Multiple logistic regression showed that DMS, EMA and NRS symptoms were significantly linked with each other and also to other insomnia criteria (sleep satisfaction, sleep quality, sleep duration, number of hours of sleep, frequency of insomnia symptoms, wake up rested / unrested and non restorative sleep).ConclusionsPatients visiting PCPs with insomnia are likely to present with severe and poly-symptomatic insomnia.     

Th2 cytokine response in Major Depressive Disorder patients before treatment

In Major Depressive Disorder (MDD), the neuroendocrine and immune systems interactions are impaired. We investigated the pro/anti-inflammatory Th1/Th2 cytokine balance in MDD patients and in non-depressed control group. The MDD subjects showed higher levels of cortisol and TNF-alpha, increased CD3+CD8+ and NK percentages, diminished B cell counts and no significant variations in CD3+CD4+ lymphocyte. Moreover, higher levels of IL-4 and IL-13 (Th2) and significantly lower measurements of IL-2 and IFN-gamma (Th1) cytokines were also observed in the MDD group. Overall, we propose that all these changes could be related to the elevated cortisol levels seen in the MDD patients. Further studies are necessary to explore these findings and its implication in future therapeutic approach of MDD patients.     

Th1 dominance in HAM/TSP and the optico-spinal form of multiple sclerosis versus Th2 dominance in mite antigen-specific IgE myelitis

To clarify the Th1/Th2 balance in spinal cord inflammation, we used ELISA to measure the total and allergen-specific IgE in 69 patients with clinically definite multiple sclerosis (MS), including 24 patients with the optico-spinal form of MS, 45 with HAM/TSP, 30 HTLV-I carriers without HAM/TSP, 40 patients with acute myelitis, 43 with neurodegenerative disorders, and 42 healthy subjects, and flow cytometry to study the intracellular IFNgamma-positive versus IL-4-positive cell ratio (intracellular IFNgamma/IL-4 ratio) in peripheral blood CD4(+) T cells in 40 patients with MS, including 17 patients with the optico-spinal form of MS, 23 with HAM/TSP, 22 with acute myelitis, 23 with neurodegenerative disorders, and 36 healthy subjects. Patients with HAM/TSP showed a significantly higher intracellular IFNgamma/IL-4 ratio, lower IL-4(+)/IFN-gamma(-) cell percentages, lower total IgE level, and lower frequency of cedar pollen-specific IgE than did the controls. The patients with optico-spinal MS showed a significantly higher intracellular IFNgamma/IL-4 ratio and higher IL-4(-)/IFN-gamma(+) cell percentages than the controls even at remission or in the convalescence phase. In contrast, in the patients with acute myelitis, the total serum IgE level and the frequency of mite antigen-specific IgE were significantly elevated in comparison to the controls, while those having mite antigen-specific IgE myelitis showed a significantly lower IFNgamma/IL-4 ratio in the CD4(+) T cells in comparison to the controls. These findings suggest that the Th1 cell response is predominant in HAM/TSP and optico-spinal MS, whereas the Th2 cell response is predominant in mite antigen-specific IgE myelitis.     

Th1 shift in CIDP versus Th2 shift in vasculitic neuropathy in CSF

To investigate the intra- and extracellular levels of various cytokines and chemokines in CSF in chronic inflammatory demyelinating polyneuropathy (CIDP) and vasculitic neuropathy (VN), 16 cytokines, IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17, IFN-gamma, TNF-alpha, G-CSF, MCP-1 and MIP-1beta, were measured in CSF supernatant by a multiplexed fluorescent bead-based immunoassay and intracellular production of IFN-gamma and IL-4 in CSF CD4+ T cells were simultaneously measured by flow cytometry in 14 patients with CIDP, 8 patients with VN and 25 patients with other noninflammatory neurologic diseases (OND). In the CSF supernatant, a significant increase of IL-17, IL-8 and IL-6, and a significant decrease of IL-4, IL-5 and IL-7 levels were detected in pretreated CIDP as compared with OND. A significant increase of IL-6, IL-8 and IL-10 levels was found in pretreated VN. Both IL-17 and IL-8 levels correlated strongly with CSF protein levels in CIDP, although the correlation of IL-6 levels was weak. In CSF CD4+ T cells, IFN-gamma+ IL-4- cell percentages were markedly elevated in CIDP compared with OND, but not in VN, resulting in a significant increase of intracellular IFN-gamma/IL-4 ratio in CIDP, even in the absence of CSF pleocytosis. The nonresponders to intravenous immunoglobulins (IVIGs) showed a significantly lower IFN-gamma- IL-4+ CD4+ T cell percentage, and tended to have a higher intracellular IFN-gamma/IL-4 ratio than the responders in CSF. Marked upregulation of Th1 cytokine, IL-17, and downregulation of Th2 cytokines, together with infiltration of IFN-gamma-producing CD4+ T cells are useful markers for CIDP, while several Th2 cytokines are upregulated in VN in CSF.     

Systemic immune parameters and sleep after ultra-low dose administration of IL-2 in healthy men

A somnogenic function is suspected for various cytokines. Foregoing experiments in humans indicated a selective increase in the production of interleukin-2 (IL-2) during sleep as compared with nocturnal wakefulness. Here, we examined whether conversely, IL-2 exerts a promoting influence on sleep. Also, the effects of IL-2 administered at ultra-low doses on systemic immune and endocrine parameters were assessed. Eighteen healthy men participated in three night sessions, receiving subcutaneously at 19:00 h either placebo or recombinant human IL-2 at doses of 1000 and 10,000 IU/kg bw. Polysomnographical recordings were obtained between 23:00 and 07:00 h. Blood was collected repeatedly to determine (i) white blood cell (WBC) counts including the enumeration of monocytes, natural killer (NK) cells, and lymphocyte subsets, (ii) serum concentrations of IL-2, soluble IL-2 receptor (sIL-2r), IL-4, IL-6, and interferon-gamma (IFN-gamma), and (iii) concentrations of adrenocorticotropin (ACTH), cortisol, thyreotropin (TSH), and growth hormone (GH). Changes after 1000 IU/kg bw IL-2 generally remained non-significant. However, distinct effects occurred after 10,000 IU/kg bw IL-2, inducing serum IL-2 concentrations selectively activating the high affinity IL-2 receptor. At this dose, IL-2 reduced the number of circulating lymphocytes (including all major subtypes) and NK cells, while counts of monocytes and neutrophils were increased. IL-4 release was stimulated and IFN-gamma concentration reduced after IL-2. Also, IL-2 increased the TSH concentration. There were no hints at a sleep promoting effect of IL-2. Immune changes suggest that nocturnal IL-2 administration induces a shift towards Th2 mediated defense.     

Insomnia and daytime neuropsychological test performance in older adults

Objectives/BackgroundThere is good documentation of the impact of insomnia on daytime cognitive function based on self-reports, but not on neuropsychological test performance. The study investigated the association of difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), and early morning awakening (EMA) complaints with daytime domain-specific neuropsychological performance in older adults.Participants/MethodsParticipants were 859 older adults (mean 71.9 years) in the Singapore Longitudinal Ageing Studies. They were interviewed and assessed at community-based eldercare activity centres and completed a sleep survey questionnaire and a battery of neuropsychological tests (Digit span, Rey Auditory Verbal Learning Test, Story memory, Brief Visuospatial Memory Test-Revised, Color Trails Test (1 and 2), Block design, and Verbal fluency).ResultsInsomnia complaints were present in 18.0% (n = 155) of participants. Controlling for the presence of other insomnia complaints, psychosocial and medical variables, and depression, EMA was independently and significantly associated with worse executive functioning (p = 0.031). DIS and DMS were not independently associated with poorer performance on any cognitive domain.ConclusionThe association of EMA among older adults with decreased executive functioning and underlying mechanistic factors should be further investigated.     

The impact of obesity and weight gain on development of sleep problems in a population-based sample

ObjectivesThe objective of this study was to investigate the role of obesity and weight gain in the development of sleep problems in a population-based cohort.Material and methodsA population-based sample of men (n = 1896, aged 40–79 years) and women (n = 5116, age ≥20 years) responded to questionnaires at baseline and follow-up after 10–13 years. Sleep problems were assessed through questions about difficulties initiating sleep (DIS), difficulties maintaining sleep (DMS), excessive daytime sleepiness (EDS), and insomnia. Body mass index (BMI) was calculated from self-reported weight and height at both baseline and follow-up, while confounding factors (physical activity, tobacco and alcohol use, somatic disease, and snoring) were based on responses at baseline.ResultsAlthough overweight and obese subjects reported more sleep problems at baseline, there was no independent association between BMI level at baseline and development of new sleep problems. Subjects in the quartile with the highest rise in BMI with a weight gain exceeding 2.06 kg/m² had a higher risk of developing DMS [adjusted odds ratio (OR) 1.58; 95% confidence interval (CI) 1.25–2.01), EDS (2.25; 1.65–3.06], and insomnia (2.78; 1.60–4.82). Weight gain was not associated with the development of DIS.ConclusionsWeight gain is an independent risk factor for developing several sleep problems and daytime sleepiness. The presence of overweight and weight gain should be considered when treating patients with sleep problems.