The transition to motherhood: linking hormones, brain and behaviour.

We are witnessing a stark increase in scientific interest in the neurobiological processes associated with pregnancy and maternity. Convergent evidence suggests that around the time of labour, first-time mothers experience a specific pattern of neuroanatomical changes that are associated with maternal behaviour. Here we provide an overview of the human neurobiological adaptations of motherhood, focusing on the interplay between pregnancy-related steroid and peptide hormones, and neuroplasticity in the brain. We discuss which brain plasticity mechanisms might underlie the structural changes detected by MRI, which hormonal systems are likely to contribute to such neuroanatomical changes and how these brain mechanisms may be linked to maternal behaviour. This Review offers an overarching framework that can serve as a roadmap for future investigations.

Cortical volume reductions in men transitioning to first-time fatherhood reflect both parenting engagement and mental health risk.

Perinatal reductions in gray matter volume have been observed in human mothers transitioning to parenthood, with preliminary evidence for similar changes in fathers. These reductions have been theorized to support adaptation to parenting, but greater investigation is needed. We scanned 38 first-time fathers during their partner's pregnancy and again after 6 months postpartum, and collected self-report data prenatally and 3, 6, and 12 months postpartum. Significant gray matter volume reductions were observed across the entire cortex but not the subcortex. Fathers who reported stronger prenatal bonding with the unborn infant, and planned to take more time off from work after birth, subsequently showed larger cortical volume decreases. Larger reductions in gray matter volume also emerged among fathers who reported stronger postpartum bonding with the infant, lower parenting stress, and more time spent with their infant. Larger volume reductions predicted more postpartum sleep problems and higher levels of postpartum depression, anxiety, and psychological distress, controlling for prenatal sleep and mental health. Volume reductions were smaller among fathers whose infants were older at the postpartum scan, indicating potential rebound. These results suggest that perinatal gray matter volume reductions might reflect not only greater parenting engagement but also increased mental health risk in new fathers.

First-time fathers show longitudinal gray matter cortical volume reductions: evidence from two international samples.

Emerging evidence points to the transition to parenthood as a critical window for adult neural plasticity. Studying fathers offers a unique opportunity to explore how parenting experience can shape the human brain when pregnancy is not directly experienced. Yet very few studies have examined the neuroanatomic adaptations of men transitioning into fatherhood. The present study reports on an international collaboration between two laboratories, one in Spain and the other in California (United States), that have prospectively collected structural neuroimaging data in 20 expectant fathers before and after the birth of their first child. The Spanish sample also included a control group of 17 childless men. We tested whether the transition into fatherhood entailed anatomical changes in brain cortical volume, thickness, and area, and subcortical volumes. We found overlapping trends of cortical volume reductions within the default mode network and visual networks and preservation of subcortical structures across both samples of first-time fathers, which persisted after controlling for fathers' and children's age at the postnatal scan. This study provides convergent evidence for cortical structural changes in fathers, supporting the possibility that the transition to fatherhood may represent a meaningful window of experience-induced structural neuroplasticity in males.

Impact of cytomegalovirus immunodominant HLA-I donor-recipient matching on the incidence and features of virus DNAemia and virus-specific T-cell immune reconstitution in unmanipulated haploidentical hematopoietic stem cell transplantation.

BACKGROUND: We investigated whether donor-recipient mismatch involving one or more cytomegalovirus (CMV) immunodominant (ID) human leukocyte antigen (HLA)-I alleles may impact on the degree of CMV pp65/immediate-early 1 (IE-1) T-cell reconstitution and the incidence of CMV DNAemia in patients undergoing unmanipulated haploidentical hematopoietic stem cell transplantation with high-dose posttransplant cyclophosphamide (PT/Cy-haplo). METHODS: Multicenter observational study including 106 consecutive adult PT/Cy-haplo patients (34 CMV ID HLA-I matched and 72 mismatched). A real-time PCR was used for plasma CMV DNA load monitoring. Enumeration of CMV-specific (pp65/IE-1) interferon (IFN)-γ-producing T cells from several patients was performed by flow cytometry by days +30, +60, +90 and +180 after transplantation. RESULTS: The cumulative incidence of CMV DNAemia, clinically significant CMV DNAemia episodes (cs-CMVi), and recurrent CMV DNAemia was comparable across CMV ID HLA-I matched and mismatched patients (71.8% vs. 80.9%, p = .95; 40.7% vs. 44.2%, p = .85; 16.4% vs. 28.1%; p = .43, respectively). The percentage of patients exhibiting detectable CMV-specific IFN-γ-producing T-cell responses (either CD8+ or CD4+ ) was similar across groups; nevertheless, significantly higher CMV-specific CD8+ T-cell counts were enumerated in the CMV ID HLA-I matched compared to mismatched patients by day +60 (p = .04) and +180 (p = .016) after transplantation. CONCLUSION: CMV ID HLA-I matching may impact on the magnitude of CMV-pp65/IE-1-specific CD8+ T-cell reconstitution; yet, this effect seemed not to have an impact on the incidence of initial, recurrent CMV DNAemia, or cs-CMVi.

Accuracy and Comprehensiveness in Recording Information of a Web-Based Application for Preoperative Assessment: A Prospective Observational Study.

PURPOSE: Preanestes@s is a web-based application that includes a smart computer-based self-assessment preoperative questionnaire (PreQuest). Preanestes@s enables remote non-telephonic preoperative assessment via a virtual visit. We aimed to determine if the American Society of Anesthesiologists (ASA) physical status classification assigned by PreQuest and virtual visit is comparable with that assigned by face-to-face assessment, and to determine the accuracy of Preanestes@s in recording complementary preoperative information. DESIGN: Prospective, observational, paired study. METHODS: This study was conducted in a tertiary teaching hospital. A total of 510 adult patients scheduled for surgery were consecutively recruited. Of these, 220 patients were included in the analysis of ASA grade agreement. FINDINGS: PreQuest and virtual visit showed higher predictive value than face-to-face assessment in detecting patients with ASA grades 1 to 2. Face-to-face assessment showed the highest rate of false negatives (ASA 3-4 misclassified as ASA 1-2), with a sensitivity of 44.2% versus 69.8% and 50% for PreQuest and virtual visit, respectively. Virtual visit showed the highest agreement with the ASA grade assigned by a panel of experts (kappa index 0.52, 95% confidence interval 0.15-0.89). PreQuest and virtual visit offered a more comprehensive registry of anthropometric data, more detailed record of chronic diseases condition, and more accurate registry of patients' treatments (virtual visit > PreQuest > face-to-face assessment). CONCLUSIONS: The combined use of PreQuest and virtual visit offers a better performance in assigning the ASA grade for non-complex patients and a more accurate and detailed record of complementary information. This finding suggests the feasibility of Preanestes@ as a tool for preoperative assessment.

An investigation of the utility of plasma Cytomegalovirus (CMV) microRNA detection to predict CMV DNAemia in allogeneic hematopoietic stem cell transplant recipients.

Precise identification of patients at highest risk for developing Cytomegalovirus (CMV) DNAemia may improve CMV infection management in the allogeneic hematopoietic stem cell transplantation (allo-HSCT) setting. Here, we studied the potential use of detecting free CMV micro(mi)RNAs circulating in plasma for predicting CMV DNAemia in this clinical scenario. A total of 62 adult allo-HSCT recipients were included in this prospective observational multicenter study. Plasma CMV DNA load was monitored using the CMV RealTime CMV PCR (Abbott Molecular, Des Plaines, IL, USA). Detection of mature CMV miRNAs in plasma drawn by days + 7, + 14 and + 30 after allo-HSCT was performed using the miScript PCR System (Qiagen, Hilden, Germany). Assays could be optimized for five out of the seven targeted CMV miRNAs: UL36-5p, US33-5p, UL148D, UL22A-5p and UL112-3p. Of the 62 patients included in the study, 42 developed a first episode of CMV DNAemia at a median of 35 days after allo-HSCT. All targeted CMV miRNA were detected early after transplantation, with CMV miRNA US33-5p and UL112-3p the most commonly found species at any time point; nevertheless, neither the detection rate of CMV miRNAs nor their abundance allowed discrimination between patients with subsequent CMV DNAemia and those with no CMV DNAemia. The data presented herein do not support any predictive utility of these CMV miRNAs for first episodes of CMV DNAemia in a cohort consisting primarily of allo-HSCT patients receiving haploidentical allografts.

Incidence, features, and outcomes of cytomegalovirus DNAemia in unmanipulated haploidentical allogeneic hematopoietic stem cell transplantation with post-transplantation cyclophosphamide.

BACKGROUND: Conflicting data have been published as to the risk of cytomegalovirus (CMV) DNAemia and CMV disease in patients undergoing haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with post-transplantation cyclophosphamide. METHODS: We conducted a multicenter retrospective study including 118 patients subjected to unmanipulated haplo-HSCT to further clarify this issue. An historic cohort comprising 165 patients undergoing other transplant modalities (HLA-matched related, matched unrelated or mismatched) was built for comparison purposes. Plasma CMV DNA monitoring was performed using two highly sensitive real-time PCR assays. RESULTS: Overall, the cumulative incidence of CMV DNAemia, recurrent CMV DNAemia, and CMV DNAemia requiring preemptive antiviral therapy in patients undergoing haplo-HSCT was 63.9%, 34.9%, and 50.1%, respectively. These figures were rather comparable for other transplant modalities (P = .22, P = .13 and P = .72, respectively). A trend toward longer duration of episodes and shorter CMV DNA doubling times was observed in haplo-HSCT patients in comparison with other transplant modalities. Furthermore, median CMV DNA peak load was significantly higher in haplo-HSCTs (P = .008), yet overall mortality by day 180 and 365 was the same across comparison groups. There were five cases of CMV disease, and all occurred in haplo-HSCT patients. This latter observation is worrying and merits further investigation. CONCLUSIONS: The incidence of initial and recurrent episodes of CMV DNAemia either requiring or not antiviral therapy in unmanipulated haplo-HSCT was comparable to other transplant modalities in our cohort.

A comparative ultrastructural study of the pecten oculi in adult, juvenile, and nestling yellow-legged gulls, Larus michahellis (Naumann, 1840).

This study aimed at examining the histological structure of the pecten oculi in the adult yellow-legged gull, Larus michahellis, and at two moments of postnatal development: during the posthatch (nestling) and juvenile periods. Particular attention was paid to differences in the diameter of vessels, the thickness of the basement membrane, and ultrastructural features of endothelial and pigmented stromal cells. Capillary endothelial cells displayed numerous microvillous-like folds projecting from their internal and external surfaces. Intercellular spaces between capillaries were occupied by pigmented stromal cells. The ultrastructure of pecten oculi underwent noticeable changes during postnatal development. The examination of the capillaries in nestlings, juveniles, and adults revealed that the formation process of vessels and pigmented stromal cells did not complete itself in the posthaching phase. The prominent feature of endothelial cells of capillaries in nestlings was that the microvilli were longer than in juvenile and adult cells, and the capillary lumen was therefore reduced. In this sense, their pigmented stromal cells showed fewer melanosomes, lacked intercellular spaces, and cellular junctions could still be observed. These results provide evidence that the pecten oculi during the posthatching phase maintains immature morphological features consistent with a role of pigmented stromal cells in the blood-retina barrier.

Stepwise functional connectivity reveals altered sensory-multimodal integration in medication-naïve adults with attention deficit hyperactivity disorder.

Neuroimaging studies indicate that children with attention-deficit/hyperactivity disorder (ADHD) present alterations in several functional networks of the sensation-to-cognition spectrum. These alterations include functional overconnectivity within sensory regions and underconnectivity between sensory regions and neural hubs supporting higher order cognitive functions. Today, it is unknown whether this same pattern of alterations persists in adult patients with ADHD who had never been medicated for their condition. The aim of the present study was to assess whether medication-naïve adults with ADHD presented alterations in functional networks of the sensation-to-cognition spectrum. Thirty-one medication-naïve adults with ADHD and twenty-two healthy adults underwent resting-state functional magnetic resonance imaging (rs-fMRI). Stepwise functional connectivity (SFC) was used to characterize the pattern of functional connectivity between sensory seed regions and the rest of the brain at direct, short, intermediate, and long functional connectivity distances, thus covering the continuum from the sensory input to the neural hubs supporting higher order cognitive functions. As compared to controls, adults with ADHD presented increased SFC degree within primary sensory regions and decreased SFC degree between sensory seeds and higher order integration nodes. In addition, they exhibited decreased connectivity degree between sensory seeds and regions of the default-mode network. Consistently, the higher the score in clinical severity scales the lower connectivity degree between seed regions and the default mode network.

Pregnancy and adolescence entail similar neuroanatomical adaptations: A comparative analysis of cerebral morphometric changes.

Mapping the impact of pregnancy on the human brain is essential for understanding the neurobiology of maternal caregiving. Recently, we found that pregnancy leads to a long-lasting reduction in cerebral gray matter volume. However, the morphometric features behind the volumetric reductions remain unexplored. Furthermore, the similarity between these reductions and those occurring during adolescence, another hormonally similar transitional period of life, still needs to be investigated. Here, we used surface-based methods to analyze the longitudinal magnetic resonance imaging data of a group of 25 first-time mothers (before and after pregnancy) and compare them to those of a group of 25 female adolescents (during 2 years of pubertal development). For both first-time mothers and adolescent girls, a monthly rate of volumetric reductions of 0.09 mm3 was observed. In both cases, these reductions were accompanied by decreases in cortical thickness, surface area, local gyrification index, sulcal depth, and sulcal length, as well as increases in sulcal width. In fact, the changes associated with pregnancy did not differ from those that characterize the transition during adolescence in any of these measures. Our findings are consistent with the notion that the brain morphometric changes associated with pregnancy and adolescence reflect similar hormonally primed biological processes.

Muscle Fitness Cut Points for Early Assessment of Cardiovascular Risk in Children and Adolescents.

OBJECTIVES: To study the cross-sectional and longitudinal (2-year follow-up) association between muscle fitness and cardiovascular disease (CVD) risk factors in youth; whether there are muscle fitness cut points associated with CVD risk (cross-sectional); and whether the health-related muscle fitness cut points identified at baseline are associated with CVD risk 2 years later. STUDY DESIGN: In total, 237 children (110 girls) aged 6-10 years and 274 adolescents (131 girls) aged 12-16 years with complete data were included in the study (10.3% drop out). The handgrip strength and the standing long jump tests were used to assess muscle fitness. CVD risk score was computed with sum of 2 skinfolds, systolic blood pressure, insulin, glucose, triglycerides, and total cholesterol/high density lipoprotein cholesterol. RESULTS: Muscle fitness at baseline was associated inversely with single CVD risk factors and CVD risk score at baseline and 2-year follow-up (all P < .05). Receiver operating characteristics curve analyses showed a significant discriminating accuracy of handgrip strength in identifying CVD risk in children and adolescents (boys: ≥ 0.367 and ≥0.473; girls: ≥ 0.306 and ≥0.423 kg/kg body mass, respectively, all P < .001). Similarly, the standing long jump cut points for children and adolescents were ≥104.5 and ≥140.5 in boys, and ≥81.5 and ≥120.5 cm in girls, respectively (all P < .05). These cut points were associated with CVD risk 2 years later (all P < .01). CONCLUSIONS: Muscle fitness is associated with present and future cardiovascular health in youth, and is independent of cardiorespiratory fitness. It should be monitored to identify youth at risk who could benefit from intervention programs.

Relative validation of the adapted Mediterranean Diet Score for Adolescents by comparison with nutritional biomarkers and nutrient and food intakes: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study.

OBJECTIVE: To investigate whether adherence to the adapted Mediterranean Diet Score for Adolescents (MDS_A) and the adapted Mediterranean Diet Quality Index for Adolescents (KIDMED_A) is associated with better food/nutrient intakes and nutritional biomarkers. DESIGN: The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study is a cross-sectional study aiming to obtain comparable data on a variety of nutritional and health-related parameters in European adolescents aged 12·5-17·5 years. SETTING: Nine European countries. PARTICIPANTS: European adolescents (n 2330) recruited to the HELENA study. Dietary intake was obtained with 24 h dietary recalls, an FFQ and a Food Choices and Preferences questionnaire. MDS_A was calculated as a categorical variable using cut-offs (MDS_A), as a continuous variable (zMDS_A) and with energy adjustments (zEnMDS_A). The KIDMED_A score was also calculated. RESULTS: Multilevel linear regression analysis showed positive associations for zMDS_A and KIDMED_A with serum levels of vitamin D, vitamin C, plasma folate, holo-transcobalamin, ß-carotene and n-3 fatty acids, while negative associations were observed with trans-fatty acid serum levels. For categorical indices, blood biomarkers showed few significant results. zMDS_A and KIDMED_A showed positive associations with vegetables and fruits intake, and negative associations with energy-dense and low-nutritious foods. zMDS_A and KIDMED_A were positively associated with all macronutrients, vitamins and minerals (all P < 0·0001), except with monosaccharides and PUFA for KIDMED_A and cholesterol for both indices (P < 0·05). CONCLUSIONS: zMDS_A and KIDMED_A have shown the strongest associations with the dietary indicators and biomarkers that have been associated with the Mediterranean diet before, and are therefore considered the most appropriate and valid Mediterranean diet scores for European adolescents.

Local functional connectivity suggests functional immaturity in children with attention-deficit/hyperactivity disorder.

Previous studies have associated Attention-Deficit/Hyperactivity Disorder (ADHD) with a maturational lag of brain functional networks. Functional connectivity of the human brain changes from primarily local to more distant connectivity patterns during typical development. Under the maturational lag hypothesis, we expect children with ADHD to exhibit increased local connectivity and decreased distant connectivity compared with neurotypically developing (ND) children. We applied a graph-theory method to compute local and distant connectivity levels and cross-sectionally compared them in a sample of 120 children with ADHD and 120 age-matched ND children (age range = 7-17 years). In addition, we measured if potential group differences in local and distant connectivity were stable across the age range considered. Finally, we assessed the clinical relevance of observed group differences by correlating the connectivity levels and ADHD symptoms severity separately for each group. Children with ADHD exhibited more local connectivity than age-matched ND children in multiple brain regions, mainly overlapping with default mode, fronto-parietal and ventral attentional functional networks (p < .05- threshold free-cluster enhancement-family-wise error). We detected an atypical developmental pattern of local connectivity in somatomotor regions, that is, decreases with age in ND children, and increases with age in children with ADHD. Furthermore, local connectivity within somatomotor areas correlated positively with clinical severity of ADHD symptoms, both in ADHD and ND children. Results suggest an immature functional state of multiple brain networks in children with ADHD. Whereas the ADHD diagnosis is associated with the integrity of the system comprising the fronto-parietal, default mode and ventral attentional networks, the severity of clinical symptoms is related to atypical functional connectivity within somatomotor areas. Additionally, our findings are in line with the view of ADHD as a disorder of deviated maturational trajectories, mainly affecting somatomotor areas, rather than delays that normalize with age.

Clustering of multiple energy balance related behaviors is associated with body fat composition indicators in adolescents: Results from the HELENA and ELANA studies.

The objective of this study was to identify clustering patterns of four energy balance-related behaviors (EBRB): television (TV) watching, moderate and vigorous physical activity (MVPA), consumption of fruits and vegetables (F&V), and consumption of sugar-sweetened beverages (SSB), among European and Brazilian adolescents. EBRB associations with different body fat composition indicators were then evaluated. Participants included adolescents from eight European countries in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescents) study (n = 2,057, 53.8% female; age: 12.5-17.5 years) and from the metropolitan region of Rio de Janeiro/Brazil in the ELANA study (the Adolescent Nutritional Assessment Longitudinal Study) (n = 968, 53.2% female; age: 13.5-19 years). EBRB data allowed for sex- and study-specific clusters. Associations were estimated by ANOVA and odds ratios. Five clustering patterns were identified. Four similar clusters were identified for each sex and study. Among boys, different cluster identified was characterized by high F&V consumption in the HELENA study and high TV watching and high MVPA time in the ELANA study. Among girls, the different clusters identified was characterized by high F&V consumption in both studies and, additionally, high SSB consumption in the ELANA study. Regression analysis showed that clusters characterized by high SSB consumption in European boys; high TV watching, and high TV watching plus high MVPA in Brazilian boys; and high MVPA, and high SSB and F&V consumption in Brazilian girls, were positively associated with different body fat composition indicators. Common clusters were observed in adolescents from Europe and Brazil, however, no cluster was identified as being completely healthy or unhealthy. Each cluster seems to impact on body composition indicators, depending on the group. Public health actions should aim to promote adequate practices of EBRB.

Amino acids intake and physical fitness among adolescents.

The aim was to investigate whether there was an association between amino acid (AA) intake and physical fitness and if so, to assess whether this association was independent of carbohydrates intake. European adolescents (n = 1481, 12.5-17.5 years) were measured. Intake was assessed via two non-consecutive 24-h dietary recalls. Lower and upper limbs muscular fitness was assessed by standing long jump and handgrip strength tests, respectively. Cardiorespiratory fitness was assessed by the 20-m shuttle run test. Physical activity was objectively measured. Socioeconomic status was obtained via questionnaires. Lower limbs muscular fitness seems to be positively associated with tryptophan, histidine and methionine intake in boys, regardless of centre, age, socioeconomic status, physical activity and total energy intake (model 1). However, these associations disappeared once carbohydrates intake was controlled for (model 2). In girls, only proline intake seems to be positively associated with lower limbs muscular fitness (model 2) while cardiorespiratory fitness seems to be positively associated with leucine (model 1) and proline intake (models 1 and 2). None of the observed significant associations remained significant once multiple testing was controlled for. In conclusion, we failed to detect any associations between any of the evaluated AAs and physical fitness after taking into account the effect of multiple testing.

Imported malaria in Spain (2009-2016): results from the +REDIVI Collaborative Network.

BACKGROUND: Imported malaria is a frequent diagnosis in travellers and migrants. The objective of this study was to describe the epidemiological and clinical characteristics of patients diagnosed with imported malaria within a Spanish collaborative network registering imported diseases (+REDIVI). In addition, the possible association between malaria and type of case, gender, age or area of exposure was explored. METHODS: Cases of imported malaria were identified among all cases registered in the +REDIVI database during the period October 2009-October 2016. Demographic, epidemiological and clinical characteristics were analysed. RESULTS: In total, 11,816 cases of imported infectious diseases were registered in +REDIVI's database between October 2009 and October 2016. Immigrants seen for the first time after migration accounted for 60.2% of cases, 21.0% of patients were travellers, and 18.8% were travellers/immigrants visiting friends and relatives (VFRs). There were 850 cases of malaria (850/11,816, 7.2%). Malaria was significantly more frequent in men than in women (56.8% vs 43.2%) and in VFR-immigrants (52.6%) as compared to travellers (21.3%), immigrants (20.7%) and VFR-travellers (5.4%) (p < 0.001). Although this data was not available for most patients with malaria, only a minority (29/217, 13.4%) mentioned correct anti-malarial prophylaxis. Sub-Saharan Africa was found to be the most common region of acquisition of malaria. Most common reason for consultation after travel was a febrile syndrome although an important proportion of immigrants were asymptomatic and presented only for health screening (27.3%). Around 5% of travellers presented with severe malaria. The most prevalent species of Plasmodium diagnosed was Plasmodium falciparum (81.5%). Malaria due to Plasmodium ovale/Plasmodium vivax was frequent among travellers (17%) and nearly 5% of all malaria cases in immigrants were caused by Plasmodium malariae. CONCLUSIONS: Malaria was among the five most frequent diagnoses registered in +REDIVI's database. Some significant differences were found in the distribution of malaria according to gender, type of case, species. Among all malaria cases, the most frequent diagnosis was P. falciparum infection in VFR-immigrant men.

Diet quality and attention capacity in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study.

Adolescence represents an important period for the development of executive functions, which are a set of important cognitive processes including attentional control. However, very little is known regarding the associations of nutrition with components of executive functions in adolescence. Thus, the aim of this study was to investigate associations of dietary patterns and macronutrient composition with attention capacity in European adolescents. This cross-sectional study included 384 (165 boys and 219 girls) adolescents, aged 12·5-17·5 years, from five European countries in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. Attention capacity was examined using the d2 Test of Attention. Dietary intake was assessed through two non-consecutive 24 h recalls using a computer-based self-administered tool. Three dietary patterns (diet quality index, ideal diet score and Mediterranean diet score) and macronutrient/fibre intakes were calculated. Linear regression analysis was conducted adjusting for age, sex, BMI, maternal education, family affluence scale, study centre and energy intake (only for Mediterranean diet score). In these adjusted regression analyses, higher diet quality index for adolescents and ideal diet score were associated with a higher attention capacity (standardised ß=0·16, P=0·002 and ß=0·15, P=0·005, respectively). Conversely, Mediterranean diet score or macronutrient/fibre intake were not associated with attention capacity (P>0·05). Our results suggest that healthier dietary patterns, as indicated by higher diet quality index and ideal diet score, were associated with attention capacity in adolescence. Intervention studies investigating a causal relationship between diet quality and attention are warranted.

Using reduced rank regression methods to identify dietary patterns associated with obesity: a cross-country study among European and Australian adolescents.

This study aims to examine repeatability of reduced rank regression (RRR) methods in calculating dietary patterns (DP) and cross-sectional associations with overweight (OW)/obesity across European and Australian samples of adolescents. Data from two cross-sectional surveys in Europe (2006/2007 Healthy Lifestyle in Europe by Nutrition in Adolescence study, including 1954 adolescents, 12-17 years) and Australia (2007 National Children's Nutrition and Physical Activity Survey, including 1498 adolescents, 12-16 years) were used. Dietary intake was measured using two non-consecutive, 24-h recalls. RRR was used to identify DP using dietary energy density, fibre density and percentage of energy intake from fat as the intermediate variables. Associations between DP scores and body mass/fat were examined using multivariable linear and logistic regression as appropriate, stratified by sex. The first DP extracted (labelled 'energy dense, high fat, low fibre') explained 47 and 31 % of the response variation in Australian and European adolescents, respectively. It was similar for European and Australian adolescents and characterised by higher consumption of biscuits/cakes, chocolate/confectionery, crisps/savoury snacks, sugar-sweetened beverages, and lower consumption of yogurt, high-fibre bread, vegetables and fresh fruit. DP scores were inversely associated with BMI z-scores in Australian adolescent boys and borderline inverse in European adolescent boys (so as with %BF). Similarly, a lower likelihood for OW in boys was observed with higher DP scores in both surveys. No such relationships were observed in adolescent girls. In conclusion, the DP identified in this cross-country study was comparable for European and Australian adolescents, demonstrating robustness of the RRR method in calculating DP among populations. However, longitudinal designs are more relevant when studying diet-obesity associations, to prevent reverse causality.