Sleep structure and cardiometabolic disorders in the general population : the Hypnolaus study

Objectives: Previous studies using subjective assessments have reported associations between sleep quantity and quality and cardiometabolic disorders, but little is known regarding the associ-ations with objective sleep characteristics. The purpose of this study was to evaluate the association between objective sleep measure sand metabolic syndrome (MS), hypertension, diabetes and obesity. Methods: 2162 subjects (51.2% women, mean age 58,11.1) from the general population were evaluated for hypertension,diabetes, overweight/obesity and MS, and underwent a full polysom-nography (PSG). PSG measured variables included: Total sleep time(TST), percentage and time spent in slow wave sleep (SWS) and in rapid eye movement (REM) sleep, sleep efficiency and arousal index(ArI) Results: In univariate analyses, MS was associated with decreased TST, SWS, REM sleep, sleep efficiency and increased ArI. After adjustment for age, gender, smoking, alcohol, physical activity, drugsthat affect sleep and depression, the ArI remained significantly higher, but the difference disappeared in subjects without significant sleep disordered breathing (SDB). Differences in sleep structure were also found according to the presence or absence of hypertension, diabetes and overweight/obesity in univariate analysis. However, these differences were attenuated after multivariate adjustment and after excluding subjects with significant SDB. Conclusions: In this population-based sample we found significant associations between sleep structure and MS, hypertension, diabetes and obesity. However, these associations were cancelled after multivariate adjustment. We conclude that normal variations in sleep contribute little if any to MS and associated disorders.

Orthogonal higher order structure and confirmatory factor analysis of the French Wechsler Adult Intelligence Scale (WAIS-III).

According to the most widely accepted Cattell-Horn-Carroll (CHC) model of intelligence measurement, each subtest score of the Wechsler Intelligence Scale for Adults (3rd ed.; WAIS-III) should reflect both 1st- and 2nd-order factors (i.e., 4 or 5 broad abilities and 1 general factor). To disentangle the contribution of each factor, we applied a Schmid-Leiman orthogonalization transformation (SLT) to the standardization data published in the French technical manual for the WAIS-III. Results showed that the general factor accounted for 63% of the common variance and that the specific contributions of the 1st-order factors were weak (4.7%-15.9%). We also addressed this issue by using confirmatory factor analysis. Results indicated that the bifactor model (with 1st-order group and general factors) better fit the data than did the traditional higher order structure. Models based on the CHC framework were also tested. Results indicated that a higher order CHC model showed a better fit than did the classical 4-factor model; however, the WAIS bifactor structure was the most adequate. We recommend that users do not discount the Full Scale IQ when interpreting the index scores of the WAIS-III because the general factor accounts for the bulk of the common variance in the French WAIS-III. The 4 index scores cannot be considered to reflect only broad ability because they include a strong contribution of the general factor.

Red blood cell structure and dynamics explored with digital holographic microspcopy

Digital holographic microscopy (DHM) is a technique that allows obtaining, from a single recorded hologram, quantitative phase image of living cell with interferometric accuracy. Specifically the optical phase shift induced by the specimen on the transmitted wave front can be regarded as a powerful endogenous contrast agent, depending on both the thickness and the refractive index of the sample. Thanks to a decoupling procedure cell thickness and intracellular refractive index can be measured separately. Consequently, Mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC), two highly relevant clinical parameters, have been measured non-invasively at a single cell level. The DHM nanometric axial and microsecond temporal sensitivities have permitted to measure the red blood cell membrane fluctuations (CMF) on the whole cell surface. ©2009 COPYRIGHT SPIE--The International Society for Optical Engineering.

Independent relations of left ventricular structure with the 24-hour urinary excretion of sodium and aldosterone.

Previous studies reported on the association of left ventricular mass index (LVMI) with urinary sodium or with circulating or urinary aldosterone. We investigated the independent associations of LVMI with the urinary excretion of both sodium and aldosterone. We randomly recruited 317 untreated subjects from a white population (45.1% women; mean age 48.2 years). Measurements included echocardiographic left ventricular (LV) properties, the 24-hour urinary excretion of sodium and aldosterone, plasma renin activity (PRA), and proximal (RNa(prox)) and distal (RNa(dist)) renal sodium reabsorption, assessed from the endogenous lithium clearance. In multivariable-adjusted models, we expressed changes in LVMI per 1-SD increase in the explanatory variables, while accounting for sex, age, systolic blood pressure, and the waist-to-hip ratio. LVMI increased independently with the urinary excretion of both sodium (+2.48 g/m(2); P=0.005) and aldosterone (+2.63 g/m(2); P=0.004). Higher sodium excretion was associated with increased mean wall thickness (MWT: +0.126 mm, P=0.054), but with no change in LV end-diastolic diameter (LVID: +0.12 mm, P=0.64). In contrast, higher aldosterone excretion was associated with higher LVID (+0.54 mm; P=0.017), but with no change in MWT (+0.070 mm; P=0.28). Higher RNa(dist) was associated with lower relative wall thickness (-0.81x10(-2), P=0.017), because of opposite trends in LVID (+0.33 mm; P=0.13) and MWT (-0.130 mm; P=0.040). LVMI was not associated with PRA or RNa(prox.) In conclusion, LVMI independently increased with both urinary sodium and aldosterone excretion. Increased MWT explained the association of LVMI with urinary sodium and increased LVID the association of LVMI with urinary aldosterone.

Phylogenetic plant community structure along elevation is lineage specific

The trend of closely related taxa to retain similar environmental preferences mediated by inherited traits suggests that several patterns observed at the community scale originate from longer evolutionary processes. While the effects of phylogenetic relatedness have been previously studied within a single genus or family, lineage-specific effects on the ecological processes governing community assembly have rarely been studied for entire communities or flora. Here, we measured how community phylogenetic structure varies across a wide elevation gradient for plant lineages represented by thirty-five families, using a co-occurrence index and net relatedness index (NRI). We propose a framework that analyses each lineage separately and reveals the trend of ecological assembly at tree nodes. We found prevailing phylogenetic clustering for more ancient nodes and overdispersion in more recent tree nodes. Closely related species may thus rapidly evolve new environmental tolerances to radiate into distinct communities, while older lineages likely retain inherent environmental tolerances to occupy communities in similar environments, either through efficient dispersal mechanisms or the exclusion of older lineages with more divergent environmental tolerances. Our study illustrates the importance of disentangling the patterns of community assembly among lineages to better interpret the ecological role of traits. It also sheds light on studies reporting absence of phylogenetic signal, and opens new perspectives on the analysis of niche and trait conservatism across lineages.

Stratification by smoking status reveals an association of CHRNA5-A3-B4 genotype with body mass index in never smokers.

We previously used a single nucleotide polymorphism (SNP) in the CHRNA5-A3-B4 gene cluster associated with heaviness of smoking within smokers to confirm the causal effect of smoking in reducing body mass index (BMI) in a Mendelian randomisation analysis. While seeking to extend these findings in a larger sample we found that this SNP is associated with 0.74% lower body mass index (BMI) per minor allele in current smokers (95% CI -0.97 to -0.51, P = 2.00 × 10(-10)), but also unexpectedly found that it was associated with 0.35% higher BMI in never smokers (95% CI +0.18 to +0.52, P = 6.38 × 10(-5)). An interaction test confirmed that these estimates differed from each other (P = 4.95 × 10(-13)). This difference in effects suggests the variant influences BMI both via pathways unrelated to smoking, and via the weight-reducing effects of smoking. It would therefore be essentially undetectable in an unstratified genome-wide association study of BMI, given the opposite association with BMI in never and current smokers. This demonstrates that novel associations may be obscured by hidden population sub-structure. Stratification on well-characterized environmental factors known to impact on health outcomes may therefore reveal novel genetic associations.

Assessing dispositional empathy in adults: A French validation of the Interpersonal Reactivity Index (IRI).

The goal of this study was to validate a French version of the Interpersonal Reactivity Index (IRI), a self-report questionnaire comprised of four subscales assessing affective (empathic concern and personal distress) and cognitive (fantasy and perspective taking) components of empathy. To accomplish this, 322 adults (18 to 89 years) completed the French version of the IRI (F-IRI). A confirmatory factor analysis confirmed the four-factor structure of the original IRI. The F-IRI showed good scale score reliability, test-retest reliability, and convergent validity, tested with the French version of the Empathy Quotient. These findings confirmed the reliability and validity of the F-IRI and suggest that the F-IRI is a useful instrument to measure self-reported empathy. In addition, we observed sex and age differences consistent with findings in the literature. Women reported higher scores in empathic concern and fantasy than men. Older adults reported less personal distress and less fantasy. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

Objective Sleep Structure and Cardiovascular Risk Factors in the General Population: The HypnoLaus Study.

STUDY OBJECTIVES: To evaluate the association between objective sleep measures and metabolic syndrome (MS), hypertension, diabetes, and obesity. DESIGN: Cross-sectional study. SETTING: General population sample. PARTICIPANTS: There were 2,162 patients (51.2% women, mean age 58.4 ± 11.1). INTERVENTIONS: Patients were evaluated for hypertension, diabetes, overweight/obesity, and MS, and underwent a full polysomnography (PSG). MEASUREMENTS AND RESULTS: PSG measured variables included: total sleep time (TST), percentage and time spent in slow wave sleep (SWS) and in rapid eye movement (REM) sleep, sleep efficiency and arousal index (ArI). In univariate analyses, MS was associated with decreased TST, SWS, REM sleep, and sleep efficiency, and increased ArI. After adjustment for age, sex, smoking, alcohol, physical activity, drugs that affect sleep and depression, the ArI remained significantly higher, but the difference disappeared in patients without significant sleep disordered breathing (SDB). Differences in sleep structure were also found according to the presence or absence of hypertension, diabetes, and overweight/obesity in univariate analysis. However, these differences were attenuated after multivariate adjustment and after excluding subjects with significant SDB. CONCLUSIONS: In this population-based sample we found significant associations between sleep structure and MS, hypertension, diabetes, and obesity. However, these associations were cancelled after multivariate adjustment. We conclude that normal variations in sleep contribute little if any to MS and associated disorders.

Independent relations of left ventricular structure with the 24-h urinary excretion of sodium and aldosterone

Objective: Previous studies reported on the association of left ventricular mass index (LVMI) with urinary sodium or with circulating or urinary aldosterone.We investigated the independent associations of LVMI with the urinary excretion of both sodium and aldosterone. Design and method: We randomly recruited 317 untreated subjects from a White population (45.1%women; mean age 48.2 years).Measurements included echocardiographic left ventricular (LV) properties, the 24 h urinary excretion of sodium and aldosterone, plasma renin activity (PRA), and proximal (RNaprox) and distal (RNadist) renal sodium reabsorption, assessed fromthe endogenous lithium clearance. Inmultivariable-adjusted models,we expressed changes in LVMI per 1 SD increase in the explanatory variables, while accounting for sex, age, systolic blood pressure and the waist-to-hip ratio. Results: LVMI increased independentlywith the urinary excretion of both sodium (+2.48 g/m2; P=0.005) and aldosterone (+2.63 g/m2; P=0.004). Higher sodium excretion was associated with increased mean wall thickness (MWT: +0.126 mm, P=0.054), but with no change in LV end-diastolic diameter (LVID: +0.12mm, P=0.64). In contrast, higher aldosterone excretion was associated with higher LVID (+0.54 mm; P=0.017), but with no change in MWT (+0.070mm; P=0.28).Higher RNadistwas associatedwith lower relativewall thickness (−0.81×10−2, P=0.017), because of opposite trends in LVID(+0.33 mm; P=0.13) and MWT (−0.130mm; P=0.040). LVMI was not associated with PRA or RNaprox. Conclusions: LVMI independently increased with both urinary sodium and aldosterone excretion. IncreasedMWT explained the association of LVMI with urinary sodium and increased LVID the association of LVMI with urinary aldosterone.

Durée et structure du sommeil et risques métaboliques et cardiovasculaires = [Sleep structure and cardiometabolic disorders]

Introduction : Plusieurs études épidémiologiques et de laboratoire basées sur des estimations subjectives de la durée et de la qualité du sommeil suggèrent que celles-ci pourraient être associées à une augmentation du risque de troubles métaboliques ou cardiovasculaires. Objectif : Dans cette étude nous avons examiné les associations entre les caractéristiques du sommeil évaluées objectivement par Polysomnographie (PSG) et le syndrome métabolique ainsi que ses composants (hypertension, diabète, obésité). Matériel et méthodes : Nous avons analysé les données de 2162 sujets de la population générale (dont le 51.2% étaient des femmes, âge moyen : 58.4±11.1 ans, fourchette d'âge: 40.5-84.4) qui ont participé à l'étude Hypnolaus. Tous les sujets ont eu une évaluation clinique et biologique et ils ont bénéficié d'une PSG complète à domicile. Résultats : Les analyses univariées ont montré que les sujets présentant un syndrome métabolique avaient une diminution du temps total de sommeil, du sommeil lent profond, du sommeil paradoxal et de l'efficacité du sommeil, ainsi qu'une augmentation de l'index de microéveils par rapport aux sujets qui n'avaient pas un syndrome métabolique. Nous avons aussi trouvé des différences significatives de la structure du sommeil en fonction de la présence ou de l'absence d'hypertension, de diabètes et de surpoids/obésité. Cependant, ces différences s'atténuent après ajustement pour des facteurs confondants (âge, genre, tabagisme, prise d'alcool, activité physique, médicaments qui affectent le sommeil, dépression, santé globale et indice de masse corporelle). Seules des différences marginales, non statistiquement significatives, persistaient dans le modèle multiajusté et après stratification en fonction de la présence de troubles respiratoires au cours du sommeil. Conclusions: Dans cet échantillon de la population générale nous avons mis en évidence des associations significatives entre la structure du sommeil et le syndrome métabolique ainsi que ses composants. Cependant, ces associations ne sont pas indépendantes des autres facteurs de risque cardiométabolique connus. Nous en concluons que les variations normales de la durée et de la structure du sommeil contribuent peu ou pas au syndrome métabolique et ses troubles associés.

Vulnerability as a heuristic for interdisciplinary research: Assessing the thematic and methodological structure of empirical life-course studies

Changes in human lives are studied in psychology, sociology, and adjacent fields as outcomes of developmental processes, institutional regulations and policies, culturally and normatively structured life courses, or empirical accounts. However, such studies have used a wide range of complementary, but often divergent, concepts. This review has two aims. First, we report on the structure that has emerged from scientific life course research by focusing on abstracts from longitudinal and life course studies beginning with the year 2000. Second, we provide a sense of the disciplinary diversity of the field and assess the value of the concept of 'vulnerability' as a heuristic tool for studying human lives. Applying correspondence analysis to 10,632 scientific abstracts, we find a disciplinary divide between psychology and sociology, and observe indications of both similarities of-and differences between-studies, driven at least partly by the data and methods employed. We also find that vulnerability takes a central position in this scientific field, which leads us to suggest several reasons to see value in pursuing theory development for longitudinal and life course studies in this direction.