Empirical Evidence for “Syndrome Z”: A Hierarchical 5-Factor Model of the Metabolic Syndrome Incorporating Sleep Disturbance Measures

Study Objective:

Sleep disturbances have been associated with individual components of the metabolic syndrome (“syndrome X”), and, although the concept has been proposed, it is not known whether sleep disturbances actually cluster with features of the metabolic syndrome to produce a unifying trait, “syndrome Z”. Therefore, we evaluated a second-order factor model, whereby syndrome Z was described by 5 first-order factors – insulin resistance, obesity, hypertension, dyslipidemia, and sleep disturbance – with the sleep disturbance factor defined using the apnea-hypopnea index, arousal index, percentage of sleep time with oxygen saturation less than 90%, and percentage of slow wave sleep.

Design:

Observational, cross-sectional study.

Setting:

Clinical research center.

Participants:

Five hundred thirty-three adults from the Cleveland Family Sleep Study who underwent polysomnography and were not treated by continuous positive airway pressure.

Measurements and Results:

When modeling syndrome Z as a second-order factor unifying 5 first-order factors, we observed good overall model fit (χ²/df = 3.20; CFI = 0.96; RMSEA = 0.06; SRMR = 0.05) and found that obesity was the most important determining factor (standardized loading = 0.85 ± standard error = 0.02; P < 0.01) followed by sleep disturbance (0.82 ± 0.03; P < 0.01), insulin resistance (0.67 ± 0.03; P < 0.01), hypertension (0.64 ± 0.04; P < 0.01), and dyslipidemia (0.60 ± 0.05; P < 0.01). Simultaneous multiple group analyses revealed that this model was essentially generalizable across age, race, and sex subgroups.

Conclusions:

Our results demonstrate that sleep disturbance co-aggregates with other metabolic features to represent a single unifying trait, syndrome Z. Although our model awaits validation in other populations, it provides a tool for better understanding the synergistic risk of syndrome Z, compared with syndrome X, on type 2 diabetes and cardiovascular disease in future studies.

Citation:

Nock NL; Larkin EK; Patel SR; Redline S. Empirical evidence for “Syndrome Z”: a hierarchical 5-factor model of the metabolic syndrome incorporating sleep disturbance measures. SLEEP 2009;32(5):615-622.     

An investigation of the quality of breast cancer information provided on the internet by voluntary organisations in Great Britain

Objective

Patients increasingly use the internet to source health information. Voluntary organisations offering information and support often provide such information on their websites. However, the internet is unregulated and information can be of poor quality. The aim of this study was to evaluate the quality of breast cancer information provided by 10 Great Britain (GB) voluntary organisations’ websites.

Methods

Quality of websites was evaluated using an investigator-designed appraisal tool based on European Commission (EC) quality criteria for health-related websites. Completeness and transparency of breast cancer information, and usability of websites, were appraised.

Results

Typically, breast cancer-specific organisations provided the highest quality information, particularly in terms of its completeness. However, great variability in quality was identified. Areas of weakness related to transparency of information, in particular disclosure of authorship, and its apparent currency.

Conclusion

Voluntary organisations providing web-based breast cancer information have progress to make to ensure information provided is complete and transparent, and websites are user-friendly. Unfortunately, informed decision-making will not be optimised if patients cannot access quality information.

Practice implications

Voluntary organisations should regularly review the quality of information on their websites. Grading of websites allows healthcare professionals to identify and signpost patients to trustworthy, up-to-date websites. Thus, ensuring patients receive high quality information.     

Outcome measures used in forensic mental health research: a structured review

Background The evidence base for forensic mental health (FMH) services has been developing since the late 1990s. Are outcome measures sound enough for the evaluation tasks? Aims To identify, from published literature, outcome measures used in FMH research and, where feasible, assess their quality. Method A structured review was undertaken of trials and intervention studies published between 1990 and 2006. Details of outcome variables and measures were abstracted. Evidence regarding most frequently occurring outcome measures was assessed. Results Four hundred and fifty different instruments were used to assess outcomes, incorporating 1038 distinct variables. Very little evidence could be found to support the measurement properties of commonly used instruments. Conclusions and implications for practice There is little consistency in the use of outcome measure in FMH research. Effort is required to reach consensus on validated outcome measures in this field in order to better inform practice. Copyright © 2009 John Wiley & Sons, Ltd.     

The spectrum of somatic and germline NF1 mutations in NF1 patients with spinal neurofibromas

Neurofibromatosis type 1 (NF1) is a common inherited complex multi-system disorder associated with the growth of various benign and malignant tumors. About 40% of NF1 patients develop spinal tumors, of whom some have familial spinal neurofibromatosis (FSNF), a variant form of NF1 in which patients present with multiple bilateral spinal tumors but have few other clinical features of the disease. We have studied 22 spinal neurofibromas derived from 14 unrelated NF1 patients. Seven of these patients satisfied the diagnostic criteria of NF1 while the remaining seven had only few features of NF1. The latter group defined as FSNF harbored significantly higher number of missense or missense and splice-site germline mutations compared to the group with classical NF1. This is the first study to describe NF1 somatic mutations in spinal neurofibromas. Loss-of-heterozygosity (LOH) was identified in 8/22 of the spinal tumors, 75% of LOH observed was found to result from mitotic recombination, suggesting that this may represent a frequent mutational mechanisms in these benign tumors. No evidence for LOH of the TP53 gene was found in these tumors.     

Drawing cartoon faces--a functional imaging study of the cognitive neuroscience of drawing

We report a functional imaging study of drawing cartoon faces. Normal, untrained participants were scanned while viewing simple black and white cartoon line drawings of human faces, retaining them for a short memory interval, and then drawing them without vision of their hand or the paper. Specific encoding and retention of information about the faces were tested for by contrasting these two stages (with display of cartoon faces) against the exploration and retention of random dot stimuli. Drawing was contrasted between conditions in which only memory of a previously viewed face was available versus a condition in which both memory and simultaneous viewing of the cartoon were possible, and versus drawing of a new, previously unseen, face. We show that the encoding of cartoon faces powerfully activates the face-sensitive areas of the lateral occipital cortex and the fusiform gyrus, but there is no significant activation in these areas during the retention interval. Activity in both areas was also high when drawing the displayed cartoons. Drawing from memory activates areas in posterior parietal cortex and frontal areas. This activity is consistent with the encoding and retention of the spatial information about the face to be drawn as a visuo-motor action plan, either representing a series of targets for ocular fixation or as spatial targets for the drawing action.     

Is a first acute symptomatic seizure epilepsy? Mortality and risk for recurrent seizure

Purpose:   To compare mortality and subsequent unprovoked seizure risk in a population-based study of acute symptomatic seizure and first unprovoked seizure due to static brain lesions.
Methods:   We ascertained all first episodes of acute symptomatic seizure and unprovoked seizure due to central nervous system (CNS) infection, stroke, and traumatic brain injury (TBI). Subjects were residents of Rochester, Minnesota, identified through the Rochester Epidemiology Project's records-linkage system between 1/1/55 and 12/31/84. Information was collected on age, gender, seizure type, etiology, status epilepticus (SE), 30-day and 10-year mortality, and subsequent episodes of unprovoked seizure.
Results:   Two hundred sixty-two individuals experienced a first acute symptomatic seizure and 148 individuals experienced a first unprovoked seizure, all due to static brain lesions. Individuals with a first acute symptomatic seizure were 8.9 times more likely to die within 30 days compared to those with a first unprovoked seizure [95% confidence intervals (CI) = 3.5–22.5] after adjustment for age, gender, and SE. Among 30-day survivors, the risk of 10-year mortality did not differ. Over the 10-year period, individuals with a first acute symptomatic seizure were 80% less likely to experience a subsequent unprovoked seizure compared with individuals with a first unprovoked seizure [adjusted rate ratio (RR) = 0.2, 95% CI = 0.2–0.4].
Discussion:   The prognosis of first acute symptomatic seizures differs from that of first unprovoked seizure when the etiology is stroke, TBI, and CNS infection. Acute symptomatic seizures have a higher early mortality and a lower risk for subsequent unprovoked seizure. These differences argue against the inclusion of acute symptomatic seizures as epilepsy.     

Underlying cause of death in incident unprovoked seizures in the urban community of Northern Manhattan, New York City

We determined underlying cause-specific mortality for incident unprovoked seizures from Northern Manhattan, New York City. We calculated the case fatality, proportionate mortality, and the underlying cause-specific standardized mortality ratios (SMRs), with U.S. death rates as the standard. Thirty-two deaths were observed between 2003 and 2007 among 209 participants. Case fatality was significantly lower for idiopathic/cryptogenic seizures versus symptomatic seizures. About 31.3% of the deaths were attributed to malignant neoplasms, 25.0% to diseases of the heart, 15.6% to influenza and pneumonia, 3.1% to cerebrovascular diseases, and 25.0% to other causes. Significant SMRs were observed for all causes (SMR = 1.6), influenza and pneumonia (SMR = 7.1), and malignant neoplasms (SMR = 2.9). Younger cases (<65 years) had increased SMRs for all causes, malignant neoplasms, and other causes. Older cases (≥65 years) had increased SMRs for influenza and pneumonia. Underlying cause of death paralleled the underlying cause of seizure in patients with symptomatic etiologies.     

Review of prospective longitudinal studies of children with ADHD: Mental health, educational, and social outcomes

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder of childhood, resulting in impairments in academic, mental health, and functional domains. Whereas the short-term effects of ADHD are well documented, much less is understood about the adolescent and adult outcomes of children diagnosed with ADHD. This article attempts to increase understanding of these outcomes by providing an integrated summary of prospective longitudinal cohort studies investigating the outcomes of children with ADHD. Particular focus is paid to mental health, educational, and social outcomes, in addition to ADHD persistence. Overall, the data show that children with ADHD experience serious functional deficits across domains in adolescence and early-adulthood. Furthermore, the impairing symptoms of ADHD do not disappear in adulthood, as was once thought. We hope that through improved understanding of risk and protective factors in ADHD, clinicians, families, and schools can better help children with ADHD reach their full potential.