Djamel Zitouni

Evidence of the influence of physical activity on the metabolic syndrome and/or on insulin resistance in pediatric populations: a systematic review

This study is aimed at updating the relationships between physical activity (PA) and the metabolic syndrome (MetS) and/or insulin resistance (IR) in youth. Cross-sectional, prospective cohort and intervention studies, which examined the effect of PA on MetS, its components and IR in children and adolescents (<18 yrs), were searched by applying a combination of criteria in the PubMed database. The electronic search of studies published from 2000-2010 yielded >150 references. Of these, 37 studies were included. Twenty-six studies (70%) were cross-sectional observation studies, and two studies (8%) were prospective cohort studies. The remaining eight studies (22%) were interventions, of which three (<10% of all included studies) were randomized controlled trials. Commonly, higher PA levels were consistently associated with an improved metabolic profile and a reduced risk for MetS and/or IR in these populations. The impact of PA on MetS and/or IR appeared to be either independent of other factors, or alternatively or simultaneously mediated by the physical fitness and adiposity of youth. However, more-robustly designed interventions (i.e., some mega-randomized controlled trials based on lifestyle interventions) and additional cohort studies are required to make definitive inference about the magnitude and role of PA as a single genuine preventive and treatment strategy for the metabolic and cardiovascular risk of youth in the current obesogenic context.

Rationale, Methodology, Implementation, and First Results of the French Out-of-hospital Cardiac Arrest Registry

Abstract Introduction. Out-of-hospital cardiac arrest (OHCA) is an important public health issue with an estimated incidence of 50,000 cases per year in France. Community survival rates for OHCA are still low (approximately 5%). An effective, recognized way to study, assess, and improve OHCA care is to create a standard-format database. Objective. The aim of this work is to present the French OHCA registry (RéAC). Methods. RéAC is a secure, web-based data management system that was initiated in 2009 and deployed nationally in June 2012. The main goal of this registry is to improve the care and survival rate of OHCA patients. The survey form is in compliance with the requirements of French organizations and is organized in accordance with the Utstein universal style. RéAC provides real-time statistical analyses and enables all French mobile emergency and resuscitation services (MERS) to assess and improve their professional OHCA care practices. Results. In June 2012, the RéAC was nationally opened for all French MERSs. In June 2013, 221 of a possible 320 MERS participated in the RéAC. A total of 15,944 OHCA have been collected (14,939 cases closed with follow-up monitoring). The current rate of inclusion is approximately 1,500 cases per month. Since August 2012, the inclusion rate has increased by 9.5% per month, while the participation rate has increased by 9% per month. The first results show that the population is mainly male (65.4%) and the mean age is 65 ± 19 years. On MERS arrival, 73.5% of the patients were in asystole. The rates of return of spontaneous circulation, survival to hospital admission, and 30-day survival are low (respectively 21.1%, 17.2%, 4.6%). Of those who survived 30 days, 84.0% had a good neurological recovery. Conclusions. The RéAC registry is a reliable observation tool to improve public health management of OHCA. It provides relevant information to adapt or to develop diagnosis, treatments, and prognostic resources. Moreover, it enables the development of targeted awareness programs for the unique purpose of increasing the survival rates of OHCA patients.

Compliance of children in northern France with physical activity recommendations

Aims: This study examined the compliance of French children with physical activity (PA) guidelines, using objective assessments of PA. Methods: The study involved 252 children aged 9.9 ± 0.9 years, with mean height and weight of 1.39 ± 0.08 m and 35.8 ± 8.8 kg, respectively. Their usual PA was evaluated during a week using an Actigraph accelerometer. Results: The time spent in a moderate-to-vigorous PA (MVPA) ranged from 142 ± 44 min.d-1 to 25 ± 18 min/day according to the cut-offs used. Boys were significantly more active than girls (p ≤ .001). Overweight/obese children spent significantly less time in MVPA as determined with cut-off points at 3200 cpm (-26%) or 3600 cpm (-35%) (p < .01). Between 5% (8% of boys vs 1% of girls, p < .0001) and 9% (14% of boys vs 3% of girls, p < .0001) of children probably met the PA guidelines. No relationships were found with socioeconomic status. Conclusions: This high proportion of insufficiently active children (> 90%), together with the relatively high proportion of overweight children in this area, advocates a more aggressive PA promotion project, which should target all children whatever their social origins.

An architecture for online comparison and validation of processing methods and computerized guidelines in intensive care units

Clinical decision support systems are a combination of software techniques to help the clinicians in their medical decision making process via functionalities ranging from basic signal analysis to therapeutic planning and computerized guidelines. The algorithms providing all these functionalities must be very carefully validated on real patient data and must be confronted to everyday clinical practice. One of the main problems when developing these techniques is the difficulty to obtain high-quality complete patient records, comprising data coming both from the biomedical equipment (high-frequency signals), and from numerous other sources (therapeutics, imagery, clinical actions, etc.). In this paper, we present an infrastructure for developing and testing such software algorithms. It is based on a bedside workstation where testing different algorithms simultaneously on real-time data is possible in the ward. It is completed by a collaborative portal enabling different teams to test their software algorithms on the same patient records, making comparisons and cross-validations more easily.

Maturity negates the gender-related difference in physical activity among youth. Is this equally justified whatever the accelerometer cut-off point used?

OBJECTIVES To examine the consistency in findings about the influence of maturity on the gender-difference in moderate-to-vigorous physical activity (MVPA) of children using different cut-off points for MVPA. DESIGN Cross-sectional observation study. METHODS The sample involved 253 children (139 boys) of 9.9±0.9 years. Their physical activity was evaluated using an Actigraph accelerometer. The biological age of children was determined with their estimated age at the peak height velocity, and maturity categories were gender-specific defined. RESULTS Boys spent more time in MVPA than girls (P<0.0001), and no maturity-related differences were obtained on the whole sample. It was only among boys that differences were found between maturity groups with cut-off points of 3000 cpm (P=0.034), 3200 cpm (P=0.024), and 3600 cpm (P=0.011). At a given maturity level, boys spent significantly more time in MVPA than girls, except with the cut-off point of 1000 cpm (P=0.07). There were higher proportions of sufficiently active boys, but significances were reached only with cut-off points above 3000 cpm. There were no maturity-related differences in the proportion of sufficiently active children as MVPA was computed using cut-off points of 1000 cpm, 2000 cpm or 3000 cpm. CONCLUSIONS The role of maturity in the gender-difference in MVPA seems unclear as one another cut-off point is used among children. Even if a relatively greater consistency was found with the three cut-off points above 3000 cpm, data comparison may require a conversion system until a consensus is reached about the exact value to be used among children.

Continuous Infusion of Ketamine for Out-of-hospital Isolated Orthopedic Injuries Secondary to Trauma: A Randomized Controlled Trial

Abstract Objective. Although ketamine has recently been demonstrated to provide a morphine-sparing effect, no previous study reports the effect of continuous infusion of ketamine for analgesia in out-of-hospital environments. The aim of this study was to compare the effect of a continuous infusion of ketamine (IK group) vs. a continuous infusion of saline (IS group) on morphine requirements in out-of-hospital trauma patients suffering from severe acute pain. Methods. In this prospective, multicenter, randomized, single-blind clinical study, patients suffering from isolated orthopedic injuries secondary to trauma with severe acute pain received a low-dose intravenous (IV) bolus of ketamine (0.2 mg·kg−1) combined with an IV bolus of morphine (0.1 mg·kg−1) and were randomized either in the IK group (IV continuous infusion of ketamine 0.2 mg·kg−1·h−1), or in the IS group (IV continuous infusion of saline at the same volume). The primary endpoint was morphine requirements in terms of total dose of morphine (excluding the baseline bolus) injected at the end of prehospital emergency care at hospital admission (final time, Tf). The secondary endpoint was evaluation of pain with visual analogic scale (VAS). Results. Sixty-six patients were enrolled. Total morphine dose was not significantly reduced with continuous infusion of ketamine (0.048 [0.000; 0.150] vs. 0.107 [0.052; 0.150] in IK and IS groups), with similar mean duration of care (median 35.0 min). Analgesia was as efficient without any significant difference in VAS at Tf between groups (3.1 ± 2.3 (IK group) vs. 3.7 ± 2.7 (IS group), p = 0.5). Conclusions. Continuous ketamine infusion did not reduce morphine requirements in severe acute pain trauma patients in the out-of-hospital emergency settings.

Does the body adiposity index (BAI) apply to paediatric populations

Abstract Objective: Validation of body adiposity index (BAI) in a paediatrics sample; and to develop, if necessary, a valid BAI for paediatrics (i.e. BAIp). Methods: A total of 1615 children (52% boys) aged 5–12 years underwent anthropometry. Their body composition was assessed using a foot-to-foot bioimpedance. The validity of BAI = (Hip circumference/Height1.5) − 18 was tested by combining correlation and agreement statistics. Then, the sample was split into two sub-samples for the construction of BAIp. A regression was used to compute the prediction equation for BAIp-based percentage of body fat (%BF). Results: The initial BAI over-estimated the %BF of children by 49% (29.6 ± 4.2% versus 19.8 ± 6.8%; p < 0.0001). The original methodology led to a BAIp = (Hip circumference/Height0.8) − 38 in children. When compared to BAI, BAIp showed both better correlation (r = 0.57; p < 0.01 versus r = 0.74; p < 0.0001) and agreement (ICC = 0.34; [95% CI = −0.19–0.65] versus ICC = 0.83; [95% CI = 0.81–0.84]). However, there were some systematic biases between the two values of %BF as exemplified by the large 95% limit of agreement [−9.1%; 8.8%] obtained. Conclusion: BAI over-estimates the %BF in children. In contrast, BAIp appears as a new index for children’s body fatness, with acceptable accuracy. In its current form, this index is valid only for large-scale studies.

Does biological maturity actually confound gender-related differences in physical activity in preadolescence?

AIM To examine: (i) if maturity-related gender differences in moderate-to-vigorous physical activity (MVPA) depend on how maturity status is defined and measured; and (ii) the influence of maturity level on compliance with PA recommendations. METHODS The study involved 253 children (139 boys) aged 9.9 ± 0.9 years, with mean stature and weight of 1.39 ± 0.08 m and 35.8 ± 8.8 kg respectively. Their PA was evaluated using an Actigraph accelerometer (Model 7164). Maturity was assessed using the estimated age at peak height velocity (APHV) and a standardized APHV by gender (i.e. centred APHV). RESULTS Boys engaged in significantly more MVPA than girls (P < 0.0001). There was a significant correlation between the centred APHV and MVPA in boys (r = 0.20; P = 0.016), but not in girls (r = 0.13; P = 0.155). An ancova controlling for the estimated APHV showed no significant interactions between gender and APHV, and the main effect of gender on MVPA was negated. Conversely, there was a significant main effect of APHV on MVPA (F 1,249 = 6.12; P = 0.014; η p (2) = 0.024). Only 9.1% of children met the PA recommendations, including 14.4% of boys and 2.6% of girls (P < 0.01). This observation also applies in both pre-APHV (12.7% of boys vs. 2.4% of girls, P < 0.001) and post-APHV children (23.8% of boys vs. 3.4% of girls, P < 0.0001). No differences in PA guidelines were observed between pre-APHV and post-APHV children. CONCLUSIONS Among prepubescent children, the influence of biological maturity on gender differences in PA may be a function of how maturity status is determined. The most physically active prepubescent children were those who were on time according to APHV.

Si-GARCH: Construction and validation of a new method for the detection of breaking points in models

ABSTRACT In this article, we define a new method (Si-GARCH) for signal segmentation based on a class of models coming from econometrics. We make use of these models not to perform prediction but to characterize portions of signals. This enables us to compare these portions in order to determine if there is a change in the signal’s dynamics and to define breaking points with an aim of segmenting it according to its dynamics. We, then, expand these models by defining a new coefficient to improve their accuracy. The Si-GARCH method was tested on several thousands of hours of biomedical signals coming from intensive care units.

Une méthode alternative pour caractériser l'environnement « obésogénique » de l'enfant. Pertinence d'une analyse factorielle des correspondances multiples (AFCM)

Le but de cette etude est de caracteriser l’environnement « obesogenique » d’un groupe d’enfants d’âge scolaire en utilisant une analyse factorielle des correspondances multiples (AFCM), comme approche alternative aux choix methodologiques traditionnels, applicable, meme aux echantillons de taille modeste. Quatre-vingt-onze enfants (39 filles et 52 garcons) âges de 10,0 ± 0,9 ans ont ete aleatoirement recrutes au sein de 2 etablis-sements scolaires publics francais. Les donnees concernant leur cadre familial, l’implication des parents, leur temps televisuel et leur comportement alimentaire ont ete obtenues par questionnaire. Leur niveau d’activite physique et leur temps sedentaire ont ete evalues au moyen d’un accelerometre (MTI Actigraph, modele 7164) pendant 3 jours, y compris un jour ferie. Les donnees ont ete traitees au moyen d’une AFCM. Une methode d’estimation du risque a ensuite ete appliquee en considerant la distribution des enfants suivant leur statut vis-a-vis du surpoids/obesite dans le plan factoriel produit par l’AFCM. Les caracteristiques « obesogeniques » sont apparues comme 4 possibilites de combinaison entre l’environne-ment familial et des comportements varies vis-a-vis de l’activite physique, la sedentarite et?l’alimentation. Le risque relatif (RR) de surpoids/obesite etait de 2,64 [1,52 ; 4,57] (p < 0,0001) pour une combinaison entre un environnement familial « defavorise » + une association activite physique faible et alimentation riche en matieres grasses et de 0,36 [0,14 ; 0,94] (p < 0,05) pour un environnement familial « favorise » + une association activite physique forte et alimentation pauvre en matieres grasses. L’AFCM apparait suffisamment robuste et pertinente pour orienter efficacement les hypotheses etiologiques et les decisions concernant les strategies d’intervention individuelle ou collective.