The association between nonrestorative sleep and health-related quality of life in Chinese adults: a cross-sectional study.

PURPOSE: Sleep problems are prevalent among the general population and can cause various health problems, which may lead to decreased quality of life. However, little is known about nonrestorative sleep and its implications. This study aimed to examine the association between nonrestorative sleep and health-related quality of life (HRQL) in Chinese adults. METHODS: Data were collected through a cross-sectional study of 500 adults in Hong Kong (66.4% female, average age of 39 years). The Short-Form-12 Health Survey version 2 (SF-12v2), Nonrestorative Sleep Scale (NRSS), Pittsburgh Sleep Quality Index, ENRICHD Social Support Instrument, Patient Health Questionnaire, Perceived Stress Scale, and Hospital Anxiety and Depression Scale were administered. Objective sleep parameters were based on participants' sleep condition over 1 week, as measured using an ActiGraph GT9X Link. RESULTS: Mean standardized scores for the physical component summary (PCS) and mental component summary (MCS) of the SF-12v2 and the NRSS were 50.33 ± 6.50, 49.00 ± 9.03, and 64.77 ± 12.75, respectively. After adjusting for sociodemographic and lifestyle characteristics, sleep quality, objective sleep parameters, social support, somatic symptoms, stress, anxiety, and depression, NRSS scores were associated with PCS (b = 0.12, 95%CI: 0.06 to 0.18, p < 0.001) and MCS (b = 0.08, 95%CI: 0.02 to 0.15, p = 0.013) scores. Furthermore, associations of NRSS score with PCS as well as MCS scores were stronger in women than in men. CONCLUSION: Nonrestorative sleep is a potentially modifiable risk factor for poor HRQL. Thus, interventions to relieve or decrease nonrestorative sleep could be beneficial for improving HRQL.

Comparison of antral follicle count and serum anti Müllerian hormone level for determination of gonadotropin dosing in in-vitro fertilization: randomized trial.

OBJECTIVE: To compare the proportion of women achieving a desired ovarian response following ovarian stimulation when gonadotropin dosing was determined based on antral follicle count (AFC) vs serum anti-Müllerian hormone (AMH) level, in women undergoing in-vitro fertilization (IVF) using the gonadotropin-releasing hormone (GnRH) antagonist protocol. METHODS: This was a randomized double-blind trial carried out in a university-affiliated assisted reproduction unit. A total of 200 women undergoing their first IVF cycle using the GnRH-antagonist protocol between April 2016 and February 2018 were randomized to determination of gonadotropin dosing based on either AFC or serum AMH level measured in the pretreatment cycle 1 month before the IVF cycle. Patients underwent IVF as per our center's standard protocol. The proportion of subjects achieving a desired ovarian response, defined as retrieval of six to 14 oocytes, was compared between the two study arms. Subgroup analysis of patients with baseline AFC > 5 and those with baseline AFC ≤ 5 was performed. Concordance in AFC and AMH categorization between the pretreatment cycle and the ovarian-stimulation cycle was assessed using Cohen's kappa (κ). RESULTS: There was no significant difference in the proportion of patients achieving a desired ovarian response between the AFC (54%) and AMH (49%) groups (P = 0.479). The median number of oocytes retrieved was nine vs seven (P = 0.070), and the median follicular output rate was 0.54 vs 0.55 (P = 0.764) in the AFC and AMH groups, respectively. Similar findings were observed on subgroup analysis of subjects with AFC ≤ 5 and AFC > 5 at the start of ovarian stimulation (P > 0.05 for all comparisons). There was moderate concordance between AFC and AMH measured in the pretreatment cycle and the stimulation cycle (κ = 0.478 and 0.587, respectively). CONCLUSION: The proportion of women achieving a desired ovarian response following ovarian stimulation using the GnRH-antagonist protocol is similar when the gonadotropin-dosing algorithm used is based on AFC or serum AMH level. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Comparación del recuento de folículos sinusales y el nivel de la hormona antimulleriana en el suero para la determinación de la dosis de gonadotrofina en la fecundación in vitro: ensayo aleatorizado OBJETIVO: Comparar la proporción de mujeres que logran una respuesta ovárica deseada tras la estimulación del ovario cuando se determinó la dosis de gonadotrofina en función del recuento de folículos sinusales (AFC, por sus siglas en inglés) frente al nivel de la hormona antimulleriana (HAM) en el suero, en mujeres que se sometieron a una fecundación in vitro (FIV) mediante el protocolo de antagonistas de la hormona liberadora de gonadotropina (GnRH, por sus siglas en inglés). MÉTODOS: Se trata de un ensayo aleatorizado doble ciego realizado en una unidad de reproducción asistida afiliada a una universidad. Un total de 200 mujeres que se sometieron a su primer ciclo de FIV y utilizaron el protocolo de antagonistas de la GnRH entre abril de 2016 y febrero de 2018 fueron asignadas al azar a la determinación de la dosis de gonadotrofina basada en el nivel de AFC o de HAM en suero, medidos en el ciclo de pretratamiento un mes antes del ciclo de FIV. Las pacientes se sometieron a una FIV según el protocolo estándar de nuestro centro. La proporción de mujeres que lograron una respuesta ovárica deseada, definida como la recuperación de seis a 14 ovocitos, se comparó entre las dos ramas del estudio. Se realizó un análisis de subgrupos de las pacientes con AFC de base >5 y de aquellas con AFC de base ≤5. La concordancia en la categorización del AFC y la HAM entre el ciclo de pretratamiento y el ciclo de estimulación ovárica se evaluó utilizando la medida estadística kappa de Cohen (κ). RESULTADOS: No hubo diferencias significativas en la proporción de pacientes que lograron una respuesta ovárica deseada entre los grupos de AFC (54%) y HAM (49%) (P=0,479). La mediana del número de ovocitos recuperados fue de nueve frente a siete (P=0,070), y la mediana de la tasa de producción folicular fue de 0,54 frente a 0,55 (P=0,764) en los grupos AFC y HAM, respectivamente. Se observaron hallazgos similares en el análisis de subgrupos de pacientes con AFC ≤5 y AFC >5 al comienzo de la estimulación ovárica (P>0,05 para todas las comparaciones). Se observó una concordancia moderada entre el AFC y la HAM medidos en el ciclo de pretratamiento y el ciclo de estimulación (κ=0,478 y 0,587, respectivamente). CONCLUSIÓN: La proporción de mujeres que logran una respuesta ovárica deseada después de la estimulación ovárica utilizando el protocolo de antagonistas de la GnRH es similar cuando el algoritmo de dosificación de gonadotrofina utilizado se basa en el nivel del AFC o de la HAM en suero.

Nonrestorative sleep scale: a reliable and valid short form of the traditional Chinese version.

PURPOSE: Previous research has suggested the essential unidimensionality of the 12-item traditional Chinese version of the Nonrestorative Sleep Scale (NRSS). This study aimed to develop a short form of the traditional Chinese version of the NRSS without compromising its reliability and validity. METHODS: Data were collected from 2 cross-sectional studies with identical target groups of adults residing in Hong Kong. An iterative Wald test was used to assess differential item functioning by gender. Based on the generalized partial credit model, we first obtained a shortened version such that further shortening would result in substantial sacrifice of test information and standard error of measurement. Another shortened version was obtained by the optimal test assembly (OTA). The two shortened versions were compared for test information, Cronbach's alpha, and convergent validity. RESULTS: Data from a total of 404 Chinese adults (60.0% female) who had completed the Chinese NRSS were gathered. All items were invariant by gender. A 6-item version was obtained beyond which the test performance substantially deteriorated, and a 9-item version was obtained by OTA. The 9-item version performed better than the 6-item version in test information and convergent validity. It had discrimination and difficulty indices ranging from 0.44 to 2.23 and - 7.58 to 2.13, respectively, and retained 92% of the test information of the original 12-item version. CONCLUSION: The 9-item Chinese NRSS is a reliable and valid tool to measure nonrestorative sleep for epidemiological studies.

A clinical prediction score using age at diagnosis and saline infusion test parameters can predict aldosterone-producing adenoma from idiopathic adrenal hyperplasia.

PURPOSE: Accurate subtyping of the primary aldosteronism into aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH) is important to direct for specific treatment modalities. The objective of the study was to compare the clinical and biochemical parameters of APA and IAH patients to derive a Clinical Prediction Score reliably predicting APA from IAH. METHODS: This was a retrospective multi-centre study recruiting 38 APA patients and 42 IAH patients from four major hospitals in Hong Kong using database from Surgical Outcomes Monitoring and Improvement Programme and Clinical Data Analysis and Reporting System. Their clinical and biochemical parameters were evaluated. RESULTS: Patients in APA group were younger than IAH group (mean age 48.6 ± 9.2 vs. 57.1 ± 7.3 years old, p < 0.001), had more suppressed renin before saline infusion in saline infusion test (SIT) (median 0.19 [IQR 0.15-0.37] vs. 0.39 [IQR 0.19-0.69] ng/mL/h, p = 0.01), and higher aldosterone level after saline infusion in SIT (median 674 [IQR 498-1000] vs. 327 [IQR 242-483] pmol/L, p < 0.001). A clinical prediction score using three parameters was devised, comprising age at diagnosis < 50 years, PRA before saline infusion in SIT ≤ 0.26 ng/mL/h, and aldosterone level after saline infusion in SIT ≥ 424 pmol/L. A score of 2 would predict APA with a sensitivity of 84.2% and specificity of 88.1%, and a score of 3 would predict APA with a sensitivity of 31.6% and specificity of 100%. CONCLUSIONS: Clinical Prediction Score based on the combination of age at diagnosis, PRA, and aldosterone level in the saline infusion tests could reliably predict APA from IAH.

Type 2 diabetes is associated with the accumulation of senescent T cells.

Type 2 diabetes is a global health priority, given that it is driven, in part, by an ageing population, the role of immune senescence has been overlooked. This is surprising, as the functional impairments of senescent T cells show strong similarities to patients with hyperglycaemia. Immune senescence is typified by alterations in T cell memory, such as the accumulation of highly differentiated end-stage memory T cells, as well as a constitutive low-grade inflammation, which drives further immune differentiation. We show here in a preliminary study that people living with type 2 diabetes have a higher circulating volume of senescent T cells accompanied with a higher level of systemic inflammation. This inflammatory environment drives the expression of a unique array of chemokine receptors on senescent T cells, most notably C-X-C motif chemokine receptor type 2. However, this increased expression of migratory markers does not translate to improved extravasation owing to a lack of glucose uptake by the T cells. Our results therefore demonstrate that the presence of senescent T cells has a detrimental impact on immune function during type 2 diabetes.

Human varicella zoster virus is not present in the semen of a man affected by chickenpox during the in vitro fertilisation of his wife.

Human varicella zoster virus (VZV) is a member of the herpes virus family and affects humans only. Information about the presence of the virus in the semen samples of men affected by chickenpox is rather limited in the literature. Here, we reported a husband was affected by VZV during in vitro fertilisation treatment of his wife treated in our centre. The semen sample was checked for the presence of VZV by the PCR technique. The PCR result found no detectable viral DNA in the semen sample. The semen sample was then used for conventional IVF insemination and subsequently a healthy baby boy was born. This single case report suggests that the semen sample of men affected by chickenpox may be safe to use for assisted reproduction methods during the VZV infective period.

Systemic lupus erythematosus patients with past neuropsychiatric involvement are associated with worse cognitive impairment: a longitudinal study.

Longitudinal studies on cognitive impairment in patients with past history of neuropsychiatric lupus (NPSLE) are scant. In this study, NPSLE patients and matched disease and healthy controls were examined with a full battery of neuropsychological tests that covered eight cognitive domains at two time-points 12 months apart. Confounders, including depressive and anxiety symptoms, were measured by the Hospital Anxiety and Depression Scale. Eighteen NPSLE, 18 patients with systemic lupus erythematosus (SLE) who had no previous cerebral involvement (non-NPSLE) and 16 healthy subjects were recruited. NPSLE patients consistently reported more cognitive and anxiety symptoms than non-NPSLE patients over both time-points. NPSLE patients had significantly worse memory, simple and complex attention compared to non-NPSLE patients, among which memory remained significantly impaired after adjustment for confounders. NPSLE patients demonstrated a trend of higher raw scores of some neurocognitive tests upon re-evaluation over 12 months, but NPSLE patients did not demonstrate any practice effect. In conclusion, NPSLE patients had significantly worse and persistently impaired memory and learning deficits compared to non-NPSLE patients over the 12-month re-assessment period.

A QSAR for the mutagenic potencies of twelve 2-amino-trimethylimidazopyridine isomers: structural, quantum chemical, and hydropathic factors.

An isomeric series of heterocyclic amines related to one found in heated muscle meats was investigated for properties that predict their measured mutagenic potency. Eleven of the 12 possible 2-amino-trimethylimidazopyridine (TMIP) isomers were tested for mutagenic potency in the Ames/Salmonella test with bacterial strain TA98, and resulted in a 600-fold range in potency. Structural, quantum chemical, and hydropathic data were calculated on the parent molecules and the corresponding nitrenium ions of all of the tested isomers to establish models for predicting the potency of the unknown isomer. The principal determinants of higher mutagenic potency in these amines are: (1) a small dipole moment, (2) the combination of b-face ring fusion and N3-methyl group, (3) a lower calculated energy of the pi electron system, (4) a smaller energy gap between the amine HOMO and LUMO orbitals (Pearson "softness"), and (5) a more stable nitrenium ion. Based on predicted potency from the average of six regression models, the isomer not yet synthesized and tested is expected to have a mutagenic potency of 0.77 revertants/microg in tester strain TA98, which is near the low end of the potency range of the isomers.

Fluctuations in nucleoside uptake and binding of the inhibitor of nucleoside transport, nitrobenzylthioinosine, during the replication cycle of HeLa cells.

Binding of the potent nucleoside transport inhibitor 6-[(4-nitrobenzyl)thio]-9-beta-D-ribofuranosylpurine (NBMPR) and rates of uptake of several nucleosides were examined at 4-hr intervals during the replication cycle of HeLa S3 cells. Monolayer cultures of synchronous cells, obtained by mitotic detachment, were assayed for high-affinity binding of NBMPR and for rates of uptake of thymidine, uridine, cytidine, adenosine, inosine, and guanosine. The number of NBMPR binding sites per cell doubled between 4 and 16 hr after detachment (late G1 and S phase); during this interval, V max 'S for uptake of cytidine and adenosine doubled, and for uridine and thymidine uptake increased about 4- and 8-fold, respectively. Rates of inosine and guanosine uptake at extracellular concentrations below saturation increased 2-fold between G1 and S phase of the cell cycle. Km 'S for cellular uptake of thymidine, uridine, cytidine, and adenosine did not change with progress through the cycle. The results presented suggest that changes in nucleoside uptake during the HeLa cell cycle were due, in part, to changes in the activity of NBMPR-sensitive transport elements in the membrane.

Longitudinal associations of parental and peer influences with physical activity during adolescence: findings from the COMPASS study. / Associations longitudinales entre l'influence des parents et des pairs et l'activité physique durant l'adolescence : résultats de l'étude COMPASS.

INTRODUCTION: To examine temporal variations in parental and peer influences on adolescent physical activity (PA) and whether these variations predicted changes in PA. METHODS: We analyzed data from Years 1, 2 and 3 of the COMPASS study. Participants were 22 909 students in Grades 9 to 12 (mean age [years] = 15.42 ± 1.12, 46% boys, 85% White), who had completed the following survey items on 2 or more consecutive occasions: age, sex, grade, race/ethnicity, moderate-to-vigorous physical activity (MVPA), parental encouragement and parental instrumental support for PA, and number of active peers. We used a linear-mixed model to investigate longitudinal effects of parental and peer influences on changes in square-root transformed average MVPA. We used a generalized-estimating-equations (GEE) model to investigate compliance with Canadian PA guidelines for youth. These models included parental encouragement, instrumental support and number of active peers as time-varying predictors, adjusting for sociodemog raphic factors and grade as covariates, and accounting for the clustering within children and schools. RESULTS: We found that adolescents perceived significantly less parental encouragement and instrumental support and reported fewer active peers as they got older. In addition, the adjusted models suggest that, for a one-unit increase in the score of parental encouragement, parental instrumental support and number of active peers, average MVPA significantly increased by 0.22 units, 0.23 units and 0.16 units, respectively. For the same one-unit increase, adjusted odds of an adolescent complying with the PA guidelines increased by 9%, 4% and 6%, respectively. CONCLUSION: Promoting parental support and facilitating the formation and maintenance of a physically active friendship network may play an important role in attenuating declines in PA during adolescence.

INTRODUCTION: Examiner les variations temporelles de l'influence des parents et des pairs sur l'activité physique des adolescents et vérifier si elles prédisent des changements dans l'activité physique. MÉTHODOLOGIE: Nous avons analysé les données des années 1, 2 et 3 de l'étude COMPASS. Les participants étaient 22 909 élèves de la 9e à la 12e année (âge moyen [ans] = 15,42 ± 1,12; 46 % de garçons; 85 % d'élèves blancs) ayant répondu à deux reprises ou plus et de façon consécutive aux éléments suivants de l'enquête : âge, sexe, année de scolarité, race ou origine ethnique, activité physique modérée à vigoureuse (APMV), encouragement parental et soutien instrumental des parents à l'égard de l'activité physique (AP) et enfin nombre de pairs actifs. Nous avons utilisé un modèle linéaire mixte pour étudier les effets longitudinaux de l'influence des parents et des pairs sur les changements dans l'APMV moyenne avec transformation racine carrée. Nous avons fait appel à un modèle d'équation d'estimation généralisée (EEG) pour examiner l'observance des Directives canadiennes en matière d'activité physique à l'intention des jeunes. Dans ces modèles, l'encouragement parental, le soutien instrumental des parents et le nombre de pairs actifs ont été traités à titre de prédicteurs variant dans le temps. Les modèles ont été ajustés en fonction des facteurs sociodémographiques et de l'année de scolarité (covariables) et ont tenu compte des regroupements des enfants et au sein des écoles. RÉSULTATS: Nous avons constaté que les adolescents, à mesure qu'ils vieillissent, perçoivent significativement moins d'encouragement et de soutien instrumental de leurs parents et déclarent un moins grand nombre de pairs actifs. De plus, les modèles ajustés semblent indiquer que, pour une augmentation d'une unité du score relatif à l'encouragement parental, au soutien instrumental des parents et au nombre de pairs actifs, l'APMV moyenne a considérablement augmenté, de respectivement 0,22, 0,23 et 0,16 unités. Pour l'augmentation d'une unité, la probabilité ajustée qu'un adolescent respecte les directives en matière d'AP s'est accrue de respectivement 9 %, 4 % et 6 %. CONCLUSION: Le fait de promouvoir le soutien parental et de contribuer à la création et au maintien d'un réseau d'amis physiquement actifs pourrait jouer un rôle important dans l'atténuation du déclin de l'activité physique durant l'adolescence.

HLA-B*38:02:01 predicts carbimazole/methimazole-induced agranulocytosis.

Thioamides antithyroid-drugs (ATDs) are important in hyperthyroid disease management. Identification of the susceptibility locus of ATD-induced agranulocytosis is important for clinical management. We performed a genome-wide association study (GWAS) involving 20 patients with ATD-induced agranulocytosis and 775 healthy controls. The top finding was further replicated. A single-nucleotide polymorphism (SNP), rs185386680, showed the strongest association with ATD-induced agranulocytosis in GWAS (odds ratio (OR) = 36.4; 95% confidence interval (CI) = 12.8-103.7; P = 1.3 × 10(-24)) and replication (OR = 37; 95% CI = 3.7-367.4; P = 9.6 × 10(-7)). HLA-B*38:02:01 was in complete linkage disequilibrium with rs185386680. High-resolution HLA typing confirmed that HLA-B*38:02:01 was associated with carbimazole (CMZ)/methimazole (MMI)-induced agranulocytosis (OR = 265.5; 95% CI = 27.9-2528.0; P = 2.5 × 10(-14)), but not associated with propylthiouracil (PTU). The positive and negative predictive values of HLA-B*38:02:01 in predicting CMZ/MMI-induced agranulocytosis were 0.07 and 0.999. Approximately 211 cases need to be screened to prevent one case. Screening for the risk allele will be useful in preventing agranulocytosis in populations in which the frequency of the risk allele is high.

Active site dynamics of the HhaI methyltransferase: insights from computer simulation.

A molecular dynamics study was performed on the DNA methyltransferase M. Hha I in a ternary complex with DNA and AdoMet in solution. Methylation involves addition of the Cys81 sulfhydryl anion to the 6-position of Cyt18, followed by a nucleophilic attack of the resultant carbanion at C5 on the AdoMet methyl group. It was found in this simulation that the distances between the sulfhydryl group (SG) of Cys81 to the C6 of Cyt18 (SG-C6) and methyl carbon (CH3) of AdoMet to the C5 of cytosine (CH3-C5) are dependent on the dihedral angle chi (O4'-C1'-N1-C2) of the nucleotide. When the chi angle of Cyt18 is low (< -80 degrees), the SG-C6 and CH3-C5 distances are large. A high chi angle (> -80 degrees) for the target cytosine residue reduces the distances for both SG-C6 and CH3-C5, and the angles formed between the cytosine ring and AdoMet correspond well to values for the transition state structures formed during methylation of cytosine from ab initio calculations. Two possible proton sources for protonation of N3 of the cytosine residue upon formation of the covalent intermediate were found in the simulation. The protonated amine group of AdoMet could provide a proton via a water bridge, or Arg163 could also be the source of the proton for N3 via a water bridge. The simulation provides insights into how the H5 of cytosine could go from the active site into solvent. Conserved residues Asn304 and Gln82 stabilize a water network within the active site of M. Hha I which provides a route for H5 to diffuse into bulk solvent. An initially distant water molecule was able to diffuse into the active site of the enzyme and replace a position of a crystallographic water molecule in close proximity to the C5 of cytosine. The movement of this water molecule showed that a channel exists between Gln82 and the AdoMet in M. Hha I which allows both water and protons to easily gain access to the active site of the enzyme.

In vitro fertilization and embryo transfer during natural cycles.

OBJECTIVE: To report the results of in vitro fertilization and embryo transfer (IVF/ET) performed during natural cycles. STUDY DESIGN: A prospective clinical study. RESULTS: Thirty-two cycles were started in 19 patients who had regular ovulatory cycles and tubal factors or unexplained infertility only as the cause of infertility. Egg collection was performed in 12 cycles, and four pregnancies resulted from ET in eight cycles. The pregnancy rates were 12.5% per cycle initiated, 33.3% per retrieval cycle and 50% per transfer. CONCLUSION: Natural cycle IVF/ET offers a low-cost alternative to patients with infertility.

Pre-implantation genetic diagnosis in Hong Kong.

This paper presents the first two successful cases of pre-implantation genetic diagnosis in Hong Kong and discusses the indications and the advantages over prenatal diagnosis. Patients should be informed about the procedure and extensively counselled about the possibility of misdiagnosis and the need for conventional prenatal diagnosis during pregnancy.

Deletions within the azoospermia factor subregions of the Y chromosome in Hong Kong Chinese men with severe male-factor infertility: controlled clinical study.

OBJECTIVE: To determine the patterns and the prevalence of microdeletions in the azoospermia factor subregions of the Y chromosome in Hong Kong Chinese men with severe male-factor infertility. DESIGN: Controlled clinical study. SETTING: Reproductive centre of a university teaching hospital, Hong Kong. PARTICIPANTS: Fifty-eight men with severe male-factor infertility who participated in the in vitro fertilisation programme from May 1998 through March 1999, and 46 male volunteers with proven fertility. MAIN OUTCOME MEASURES: Polymerase chain reaction analysis of DNA from peripheral blood lymphocytes using six loci spanning the AZFa, AZFb, and AZFc subregions of the Y chromosome. RESULTS. No microdeletions were detected in the fertile controls or in patients with obstructive azoospermia. Deletions within the AZFc subregion were found in 9% (4/44) of men with non-obstructive azoospermia or severe oligospermia. Neither AZFa nor AZFb deletions were detected in any participants. CONCLUSION: Deletions within the azoospermia factor subregions of the Y chromosome are associated with severe male-factor infertility in Hong Kong Chinese men.

Factors associated with development of excessive fatness in children and adolescents: a review of prospective studies.

The purpose of this review was to examine the factors that predict the development of excessive fatness in children and adolescents. Medline, Web of Science and PubMed were searched to identify prospective cohort studies that evaluated the association between several variables (e.g. physical activity, sedentary behaviour, dietary intake and genetic, physiological, social cognitive, family and peer, school and community factors) and the development of excessive fatness in children and adolescents (5-18 years). Sixty-one studies met the eligibility criteria and were included. There is evidence to support the association between genetic factors and low physical activity with excessive fatness in children and adolescents. Current studies yielded mixed evidence for the contribution of sedentary behaviour, dietary intake, physiological biomarkers, family factors and the community physical activity environment. No conclusions could be drawn about social cognitive factors, peer factors, school nutrition and physical activity environments, and the community nutrition environment. There is a dearth of longitudinal evidence that examines specific factors contributing to the development of excessive fatness in childhood and adolescence. Given that childhood obesity is a worldwide public health concern, the field can benefit from large-scale, long-term prospective studies that use state-of-the-art measures in a diverse sample of children and adolescents.