Social jetlag is associated with adverse cardiometabolic latent traits in early adolescence: an observational study.

Introduction: Adolescence is marked by physiological and social changes, such as puberty, increased responsibilities and earlier school start times. This often leads to insufficient sleep on school nights and the need to compensate for lost sleep on weekends, causing a misalignment between biological and social times, which has been termed social jetlag (SJL). SJL triggers stress responses and is associated with several negative health outcomes, including higher cardiometabolic risk in adults. In adolescence, however, SJL has only been consistently related to increases in adiposity but its association with other cardiometabolic indicators are unclear. Method: In a sample of 278 healthy early adolescents (9-15 years of age; 168 girls) we investigated: 1) whether self-reported SJL is associated (using path analyses) with a cardiometabolic status latent factor obtained by testing the best fitting model via confirmatory factor analyses from an initial set of eight indicators [body mass index (BMI), waist/height ratio, triglyceride concentration, diastolic and systolic blood pressure, glycated hemoglobin, total cholesterol/high-density lipoprotein ratio (chol/HDL), and % body fat]; and 2) whether age and/or pubertal status influence the association between SJL and cardiometabolic status. Result: We found that, for girls, higher SJL was associated with more adverse cardiometabolic latent scores (the shared variance of BMI, waist/height ratio, chol/HDL and systolic blood pressure, which had acceptable model fit indices). However, the role of age and pubertal status in this association was unclear for both sexes. Discussion: SJL was associated with adverse cardiometabolic latent traits beyond increases in adiposity in this observational study in early female adolescents. Because disruptions of circadian rhythms are believed to lead to dysregulated energy homeostasis and not vice-versa, our findings highlight the need for sleep interventions in adolescence to help reduce the global burden of cardiometabolic ill health, especially in girls.

Reappraising the role of dopamine in adolescent risk-taking behavior.

Adolescence is characterized by increased risk-taking, which is often ascribed to developmental changes in dopaminergic signaling. Popular models propose that these behaviors are caused by dopamine-induced hypersensitivity to rewards, which overrides adolescents' immature self-control mechanisms. However, these models are often based on oversimplified notions about the workings and functions of dopamine. Here we discuss the relationship between changes in the dopaminergic system and adolescent behavior in light of current theories/models about the functions of dopamine. We show that dopamine is linked to learning, adaptive decision-making under uncertainty, and increased motivation to work for rewards. Thus, changes in the dopaminergic system contribute to the maturation of cognitive control through various mechanisms, contrary to the false dichotomy between reward processing and self-control. Finally, we note that dopamine interacts with a number of other neuromodulator systems, which also change during adolescence, but that have been largely ignored in the field of adolescent development. A full understanding of adolescent behavior will require these neurochemicals and their interactions with dopamine to be taken into account.

Factors that influence morningness-eveningness and daytime sleepiness: A cross-cultural comparison of Iranian and Brazilian adolescents.

As adolescents get older, they become more evening oriented and, because they are usually expected to wake early to attend school, they often present daytime sleepiness, which is associated with negative outcomes. It is still unclear if this is similar cross-culturally. Here, we studied morningness-eveningness and daytime sleepiness in early adolescence from two different developing nations (Brazil and Iran). A total sample of 697 Iranian and Brazilian early adolescents (9- to 15-year-old; 358 boys) from Tehran, Iran, and São Paulo, Brazil, varying in age and parental schooling (a proxy of socioeconomic status: SES) completed the Morningness-Eveningness Scale for Children (MESC) and the Pediatric Daytime Sleepiness Scale (PDSS) and reported their total sleep time on school nights. They also filled in the Pubertal Developmental Scale to determine their pubertal status. A negligible cross-cultural difference in morningness-eveningness was found, indicating that Brazilians showed a slight circadian-phase delay compared with Iranians throughout all tested ages. There was also seen a very slight increase in phase delay as early adolescents aged, indicative of more eveningness. However, there were no country differences in daytime sleepiness once total sleep time during school nights was controlled for, which was the only factor that affects PDSS scores.

Sex-specific association between urinary kisspeptin and pubertal development.

Kisspeptins play a crucial role during pubertal development, but little is known about how their peripheral concentrations relate to sexual maturation. This is partly due to the lack of non-invasive, quick, and reliable peripheral kisspeptin measures, which limit widespread testing. Here, we investigated the relationship between kisspeptin concentrations measured from midstream urine samples with 2-h retention periods and developmental markers (age, self-reported pubertal status, and saliva concentrations of testosterone and DHEA sulphate ) in 209 typically developing 9- to 15-year-old males and females. As a result of the study, we found marked sex differences. Kisspeptin concentrations were similar between sexes until around 12 years of age, but, thereafter, kisspeptin concentrations in females did not change significantly, whereas, in males, there was a clear positive correlation with developmental measures. Our results replicate previous findings regarding kisspeptin concentration changes across the pubertal transition obtained from blood samples, suggesting that measuring these peptides in urine has the potential for exploring kisspeptins' peripheral effects and their associations with pubertal status.

Bidirectional longitudinal dynamics of self-reported total sleep time and perceived stress: Establishing potential causal relationships.

OBJECTIVE: Most studies in developing countries suggest that less total sleep time (TST) increases subsequent perceived stress (PS) more consistently than the inverse, but have used statistical models that are not optimal when ratings are measured in close proximity. METHODS: We used multilevel dynamic structural equation modeling with Bayesian estimation, ideal for assessing longitudinal daily dynamic interplay between self-reported TST and PS (minimum of 30 days) in 92 Brazilian pre-university students. RESULTS: TST showed lower inertia than PS (autoregressive effect: TST perturbations influenced subsequent TST ratings less so than corresponding PS measures) and exerted negative prospective effects on PS (cross-lagged effect). CONCLUSION: In our developing nation sample, PS deviations from mean ratings took longer to return to baseline values than TST and PS was more sensitive to changes in prior TST than vice-versa, confirming previous findings. Future studies should confirm these findings with objective TST and stress measures.

Forming and updating vaccination beliefs: does the continued effect of misinformation depend on what we think we know?

People may cling to false facts even in the face of updated and correct information. The present study confronted misconceptions about the measles, mumps and rubella vaccine and a novel, fictitious Zika vaccine. Two experiments are reported, examining misconceptions as motivated by a poor risk understanding (Experiment 1, N = 130) or the exposure to conspiracy theories (Experiment 2, N = 130). Each experiment featured a Misinformation condition, wherein participants were presented with fictitious stories containing some misinformation (Experiment 1) and rumours focused on conspiracy theories (Experiment 2) that were later retracted by public health experts and a No misinformation condition, containing no reference to misinformation and rumours. Across experiments, participants were more hesitant towards vaccines when exposed to stories including vaccine misinformation. Notwithstanding, our results suggest a positive impact of a trusted source communicating the scientific consensus about vaccines. Zika virus represents a particular case showing how missing information can easily evolve into misinformation. Implications for effective dissemination of information are discussed.

Preserved executive functioning and low stress symptoms in children treated for acute lymphoblastic leukemia.

Pediatric cancer treatment can negatively impact cognitive and psychosocial development, although it has been suggested that these adverse effects may be minimized when children have higher resilience and better executive functioning. We aimed to evaluate the impact of pediatric Acute Lymphoblastic Leukemia (ALL) treatment on executive function, resilience and stress in survivors and to investigate correlations between executive functioning and resilience and between executive functioning and stress. The neuropsychological assessment was performed in 32 ALL survivors aged 7-17 years and 28 age-, sex- and socioeconomic status matched controls. Executive functioning was assessed by inhibitory control, mental flexibility and working memory tasks. Children's self-report scales were used to assess stress symptoms and resilience. Results revealed no executive function impairment nor stress symptom differences between ALL survivors and control group. In the ALL group, executive function and resilience were positively correlated, whereas executive function and stress were negatively correlated. We concluded that ALL treatment was not associated with impairment in executive functioning nor to increased stress symptoms in our sample. ALL survivors with better performance in mental flexibility and inhibition tasks reported fewer stress symptoms and more resilience, indicating a possible relationship between these variables.

Probing different aspects of short and ill-timed sleep in adolescents using the Morningness-Eveningness Scale for Children.

Sleep problems among adolescents are believed to be related to the circadian changes that occur at this age. Therefore, most self-report instruments that measure sleep patterns in adolescence focus solely on measuring circadian rhythms. However, sleep-wake cycles reflect both circadian and homeostatic processes. Recently, it was shown that answers to the Morningness-Eveningness Questionnaire for adults, which is used to assess circadian typology, were able to identify three interrelated latent factors: two that can be conceptualized as homeostatic (sensitivity to the build-up of sleep pressure and efficiency of dissipation of sleep pressure) and a less well-defined factor related to activity preference time (APT). To better understand self-reported changes in sleep patterns in adolescents we applied confirmatory factor analysis to explore whether responses to the Morningness-Eveningness Scale for Children (MESC) could also identify these three factors. The sample comprised 397, 9- to 17-year-olds. A three-correlated and a bifactor-(S-1) model (with sleep onset characteristics as a reference factor) had acceptable/good fit indices. This indicates that the MESC captures dissociable, but interrelated, homeostatic and circadian processes in addition to APT. These factors correlated with corresponding reported sleep habits, showing individual differences that may be more associated with sleep difficulties than the effects of age, which only correlated very modestly with some sleep habits. Our results indicate that the MESC can show distinct individual differences in three sleep factors that can help identify adolescents at higher risk of sleep-related problems that may require factor-specific interventions.

Feasibility of Remote Performance Assessment Using the Free Research Executive Evaluation Test Battery in Adolescents.

Lockdowns and other preventive measures taken to curb the spread of diseases such as COVID-19 have restricted the use of face-to-face cognitive assessment. Remote testing may be an alternative, but it should first be shown to be comparable to in-person assessment before being used more widely, during and after the pandemic. Our aim was to evaluate the suitability of online, examiner-mediated administration of an open-access battery of executive function tests (the Free Research Executive Evaluation battery, or FREE) that can be adapted considering various characteristics of diverse populations and therefore used worldwide. A total of 96 9-15-year olds (42 girls) were tested, half of whom online through video calls mediated by an examiner. Their performance was compared to that of the other 48 individuals tested face-to-face, who were matched against the online-tested participants for age, pubertal status, sex, and parental schooling. The battery consists of two tests of the following executive domains: Updating (2-Back and Number Memory tests), Inhibition (Stroop Victoria and Stroop Happy-Sad), and Switching (Color Shape and Category Switch). Answers were vocal and self-paced, and the examiner recorded accuracy and time taken to complete in-person and online tasks. Only free software is needed for the assessment. Executive measures obtained from the tasks did not differ statistically between online and in-person tested participants and effects sizes of group effects were small, thus showing that the FREE test battery holds promise for online cognitive assessment, pending confirmation in different samples and further validation studies.

Factor structure and psychometric properties of the Persian versions of the Pediatric Daytime Sleepiness Scale and Morningness-Eveningness Scale for Children.

BACKGROUND: The Pediatric Daytime Sleepiness Scale (PDSS) and the Morningness-Eveningness Scale for Children (MESC) are widely used to measure two important facets of sleep patterns, but neither have been adapted and validated for use in Iran. The purpose of this study was to examine the psychometric properties and factor structure of the Persian versions of the PDSS and the MESC in a sample of Iranian adolescents. MATERIALS AND METHODS: The Persian versions of PDSS and MESC were translated and administered to a representative sample (n = 407) of Iranian early adolescents, aged 9-15 years, who attended school in morning shifts. The factor structure of both scales, found in prior studies, was tested using Confirmatory Factor Analyses to assess their validity and reliability. RESULTS: The results revealed that the model fit indices of the one factor solution of the PDSS and the two factor solution of the MESC were acceptable to good. A high Pearson correlation was found between raw and latent factor scores for the PDSS and the two factors derived from the MESC (i.e., Morningness and Planning). Furthermore, the higher the PDSS score (more daytime sleepiness), the lower the MESC scores (more eveningness), indicating criterion validity of the scales showing the expected increase in daytime sleepiness in evening oriented adolescents who wake up early for attending school. CONCLUSION: The Persian versions of the PDSS and the MESC can be considered reliable and valid tools for evaluating, respectively, daytime sleepiness and morningness-eveningness in the adolescent population of Iran.

An Adaptable, Open-Access Test Battery to Study the Fractionation of Executive-Functions in Diverse Populations.

The umbrella-term 'executive functions' (EF) includes various domain-general, goal-directed cognitive abilities responsible for behavioral self-regulation. The influential unity and diversity model of EF posits the existence of three correlated yet separable executive domains: inhibition, shifting and updating. These domains may be influenced by factors such as socioeconomic status (SES) and culture, possibly due to the way EF tasks are devised and to biased choice of stimuli, focusing on first-world testees. Here, we propose a FREE (Free Research Executive Function Evaluation) test battery that includes two open-access tasks for each of the three abovementioned executive domains to allow latent variables to be obtained. The tasks were selected from those that have been shown to be representative of each domain, that are not copyrighted and do not require special hardware/software to be administered. These tasks were adapted for use in populations with varying SES/schooling levels by simplifying tasks/instructions and using easily recognized stimuli such as pictures. Items are answered verbally and tasks are self-paced to minimize interference from individual differences in psychomotor and perceptual speed, to better isolate executive from other cognitive abilities. We tested these tasks on 146 early adolescents (aged 9-15 years) of both sexes and varying SES, because this is the age group in which the executive domains of interest become distinguishable and in order to confirm that SES effects were minimized. Performance was determined by Rate Correct Scores (correct answers divided by total time taken to complete blocks/trial), which consider speed-accuracy trade-offs. Scores were sensitive to the expected improvement in performance with age and rarely/inconsistently affected by sex and SES, as expected, with no floor or ceiling effects, or skewed distribution, thus suggesting their adequacy for diverse populations in these respects. Using structural equation modeling, evidence based on internal structure was obtained by replicating the three correlated-factor solution proposed by the authors of the model. We conclude that the FREE test battery, which is open access and described in detail, holds promise as a tool for research that can be adapted for a wide range of populations, as well as altered and/or complemented in coming studies.

What are we measuring with the morningness-eveningness questionnaire? Exploratory factor analysis across four samples from two countries.

Individual variability in diurnal preference or chronotype is commonly assessed with self-report scales such as the widely used morningness-eveningness questionnaire (MEQ). We sought to investigate the MEQ's internal consistency by applying exploratory factor analysis (EFA) to determine the number of underlying latent factors in four different adult samples, two each from the United Kingdom and Brazil (total N = 3,457). We focused on factors that were apparent in all samples, irrespective of particular sociocultural diversity and geographical characteristics, so as to show a common core reproducible structure across samples. Results showed a three-factor solution with acceptable to good model fit indexes in all studied populations. Twelve of the 19 MEQ items in the three-correlated factor solution loaded onto the same factors across the four samples. This shows that the scale measures three distinguishable, yet correlated constructs: (1) items related to how people feel in the morning, which we termed efficiency of dissipation of sleep pressure (recovery process) (items 1, 3, 4, 5, 7, 9, 13, and 19); (2) items related to how people feel before sleep, which we called sensitivity to buildup of sleep pressure (items 2, 10, and 12); and (3) peak time of cognitive arousal (item 11). Although the third factor was not regarded as consistent since only one item was common among all samples, it might represent subjective amplitude. These results suggested that the latent constructs of the MEQ reflect dissociable homeostatic processes in addition to a less consistent propensity for cognitive arousal at different times of the day. By analyzing answers to MEQ items that compose these latent factors, it may be possible to extract further knowledge of factors that affect morningness-eveningness.

A reappraisal of acute doses of benzodiazepines as a model of anterograde amnesia.

OBJECTIVE: Acute administration of benzodiazepines is considered a pharmacological model of general organic anterograde amnesias (OAA). We sought to determine which type of amnesia these drugs best model by comparing the effects of diazepam with those reported in amnesiacs regarding working memory capacity (WMC), susceptibility to retroactive interference (RI), and accelerated forgetting. METHODS: In this double-blind, parallel-group design study, 30 undergraduates were randomly allocated to acute oral treatments with 15 mg diazepam or placebo. WMC and story recall were assessed pre- and post-treatment. Story presentation was succeeded by 10 min of RI (spotting differences in pictures) or minimal RI (doing nothing in a darkened room). Delayed story recall was assessed under diazepam and 7 days later in a drug-free session to assess accelerated forgetting. RESULTS: Recall of stories encoded under diazepam, whether reactivated or not, was severely impaired (anterograde amnesia). However, diazepam did not impair WMC, increase susceptibility to RI, or accelerate forgetting. CONCLUSIONS: Diazepam's amnestic effects mirror those in patients with probable severe medial temporal damage, mostly restricted to initial consolidation and differ from other OAA (Korsakoff syndrome, frontal, transient epileptic, posttraumatic amnesia, and most progressive amnesias) in terms of WMC, susceptibility to RI and accelerated forgetting.

Improving retention by placing retrieval practice at the end of class: a naturalistic study / Mejorando la retención al realizar la práctica de recuperación al final de la clase: un estudio naturalístico

Abstract Attempting to recall previously encountered information by being tested or quizzed (retrieval practice: RP) enhances memory. In real classrooms, however, it is unclear when testing should take place (placement) in order to elicit better learning. We tested students using authentic undergraduate-course materials with two placements, followed by collective feedback: (a) at the end of the class in which content was taught; or (b) at the beginning of the next class. Re-teaching (RT) the same content through lecturer led-reviews at the same placements was used as a control condition. RP and RT plus feedback took 15 min of 100 min-long classes and were applied during 12 classes after which retention was assessed by exams. Participants were 114 students enrolled in a biweekly taught course. Testing (RP) once at the end of the same class in which content was taught boosted academic scores by around 10% compared to the other manipulations.

Resumen El intento de recordar la información presentada previamente mediante pruebas o cuestionarios (práctica de recuperación, RP) mejora la memoria. Sin embargo, en las clases reales no está claro en qué momento debe realizarse las pruebas para obtener un mejor aprendizaje. Probamos a los estudiantes utilizando materiales auténticos de cursos de licenciatura en dos momentos, seguidos de una retroalimentación colectiva: (a) al final de la clase en la que se enseñó el contenido; o (b) al principio de la siguiente clase. La reenseñanza (RT) del mismo contenido a través de revisiones dirigidas por el profesor en el mismo momento se utilizó como condición de control. La RP y la RT más la retroalimentación tomaron 15 minutos de clases de 100 minutos de duración y se aplicaron durante 12 clases después de las cuales la retención fue evaluada por exámenes. Los participantes fueron 114 estudiantes inscritos en un curso impartido cada dos semanas. Las pruebas (RP) realizadas una vez al final de la misma clase en la que el contenido se enseñó, aumentó los resultados académicos en alrededor de un 10% en comparación con las otras manipulaciones.

Práctica de recordar: ¿a cuáles factores los educadores deben atentarse / Prática de lembrar: a quais fatores os educadores devem se atentar? / Retrieval practice: which factors should educators pay attention to?

A prática de lembrar (retrieval practice) ou efeito da testagem (testing-effect) é uma estratégia de estudo que envolve tentar lembrar informações às quais fomos anteriormente expostos. Embora essa prática aumente o tempo de retenção de informações comparada às formas tradicionais de estudar, dentre várias outras vantagens com ampla evidência científica, essa estratégia não costuma ser a mais usada entre alunos. Educadores devem, assim, auxiliar estudantes a utilizarem essa estratégia em seu cotidiano. Com o intuito de otimizar sua aplicabilidade, o presente artigo discute quais fatores interferem nessa prática, incluindo: a importância de feedback, a forma com que a prática de lembrar é realizada e o formato de resposta dos alunos, o número de repetições de tentativas de recordar informações e o intervalo entre essas repetições. A apropriação do conhecimento sobre esses fatores influencia positivamente a implantação da técnica em sala de aula, promovendo assim uma educação baseada em evidências.

La práctica de recordar (retrieval practice) el efecto de la verificación (testing-effect) es una estrategia de estudio que abarca tentar lembrar informaciones a las cuales fuimos anteriormente expuestos. Aunque esa práctica aumente el tiempo de retención de informaciones comparada a las formas tradicionales de estudiar, entre diversas otras ventajas con amplia evidencia científica, esa estrategia no costumbra ser la más usada entre alumnos. Educadores deben, así, auxiliar estudiantes a utilizar esa estrategia en su cotidiano. Con el intuito de optimizar su aplicabilidad, en el presente artículo discute cuales factores interfieren en esa práctica, incluyendo: la importancia de feedback, la forma con que la práctica de recordar es realizada y el formato de respuesta de los alumnos, el número de repeticiones de tentativas de recordar informaciones y el intervalo entre esas repeticiones. La apropiación del conocimiento sobre esos factores influencia positivamente la implantación de la técnica en sala de clase, promoviendo así una educación basada en evidencias.

Retrieval practice, or the testing effect, is a study technique that involves trying to remember information to which we were previously exposed. Although this practice increases the long-term-retention of information compared to traditional study techniques, among several other advantages with ample scientific evidence, this strategy is not usually the most often used among students. Educators should help students to use this technique in their daily lives. In order to optimize its applicability, this article discusses which factors interfere in this practice, including: the importance of feedback, the way in which retrieval practice is carried out and the response format, the number of repetitions of retrieval attempts to recall information and the interval between these repetitions. The appropriation of knowledge about these factors positively influences the implementation of this technique in the classroom, thus promoting evidence-based education.

A fractionated analysis of hot and cool self-regulation in cigarette smokers from different socioeconomic backgrounds.

Smoking cigarettes and low socioeconomic status (SES) are both related to impaired cognition. However, it is unknown whether people of lower SES, who comprise most tobacco smokers worldwide, are more susceptible to cognitive impairment associated with smoking. In this non-randomized, cross-sectional study we investigated the effects of cigarette smoking, SES and their interaction on dissociable executive or "cool" and "hot" measures of behavioural self-regulation. Participants (n = 80) were selected among young physically and mentally healthy smokers and non-smokers who had graduated high school and were from different SES backgrounds. Cool self-regulation was measured by executive function tasks that tap inhibition, updating, shifting, dual tasking, planning, access to long-term memory (semantic fluency), and working memory capacity. Hot measures assessed self-reported impulsivity, delay discounting and risk taking. Exposure to tobacco (cotinine, exhaled carbon monoxide, tobacco dependence, cigarette consumption) was assessed to determine to what extent it mediated the cognitive effects of smoking. Nicotine abstinence and its acute effects were controlled, as were sex, age, schooling, and psychiatric symptoms despite the fact that smokers and non-smokers were selected as being as similar as possible in these demographic characteristics. Lower SES (less years of parental schooling) was associated with worse performance on tasks that measured all cool domains except dual tasking and fluency, while smoking status was related to impaired delayed discounting and impulsivity (hot domains), effects that were not mediated by tobacco exposure. Smoking and SES, however, did not interact. In short, impaired performance in measures of most cool skills was associated with SES irrespective of smoking status; in contrast, regardless of SES, smokers showed specific impairment in hot self-regulation domains (more difficulty resisting immediate temptations and weighing future consequences of actions). Possible explanations for the lack of mediation of tobacco exposure on hot skills of smokers are discussed.

Adapted version of the Pubertal Development Scale for use in Brazil.

OBJECTIVE: To determine whether scores in an adapted version of the self-assessment Pubertal Development Scale into Portuguese match those from the gold standard in pubertal development (Tanner scale). METHODS: This was a cross-sectional study with a convenience sample of 133 children and adolescents aged nine to 17 years (59 males; mean age of 13 years and six months, with standard deviation = 25 months). Youngsters completed the Pubertal Development Scale and were then examined by specialists in adolescent medicine. RESULTS: Exact absolute agreement of pubertal stages were modest, but significant associations between measures (correlation; intra-class correlation coefficients of consistency) showed that the Pubertal Development Scale adequately measures changes that map onto pubertal development determined by physical examination, on par with international publications. Furthermore, scores obtained from each Pubertal Development Scale question reflected adequate gonadal and adrenal events assessed by clinical ratings, mostly with medium/high effect sizes. Latent factors obtained from scores on all Pubertal Development Scale questions had excellent fit indices in Confirmatory Factor Analyses and correlated with Tanner staging. CONCLUSIONS: We conclude that self-assessment of body changes by youngsters using the Portuguese version of the Pubertal Development Scale is useful when estimates of pubertal progression are sufficient, and exact agreement with clinical staging is not necessary. The Pubertal Development Scale is, therefore, a reliable instrument for use in large-scale studies in Brazil that aim at investigating adolescent health related to pubertal developmental. The translated version and scoring systems are provided.

Birth weight, verbal cognition in early adolescence, and lexical and reading skills in late adolescence: a formal mediation analysis using a potential outcomes approach.

BACKGROUND: Oral and written language in late adolescence are influenced by many pre- and postnatal factors, including cognitive performance at earlier ages. We investigated whether the association between birth weight and lexical knowledge and reading comprehension in late adolescence (14-16 years) is mediated by verbal cognition during early adolescence (10-11 years). METHODS: We conducted a mediation analysis via a potential outcomes approach to data from three United Kingdom (UK) prospective birth cohorts - The National Child Development Study (NCDS; year of birth (Y.B.) = 1,958; analytic sample size (A.N.) = 9,399; original sample size (O.N.) = 18,558), British Cohort Study (BCS70; Y.B. = 1,970; A.N. = 6,591; O.N. = 17,196), and Millennium Cohort Study (MCS; Y.B. = 2,000-2,001; A.N. = 3,950; O.N. = 18,552) - to evaluate the indirect effects of birth weight on lexical knowledge (BCS and MCS) and reading comprehension measures (NCDS) in adolescence. RESULTS: We found an indirect effect but no statistically significant direct effects for the BCS and MCS cohorts. The proportion of the effect of birth weight on oral and written language in late adolescence mediated by early adolescence verbal cognition was 59.19% (BCS) and 8.41% (MCS) for lexical knowledge and 61.00% when the outcome was reading comprehension (NCDS). Sensitivity analyses, used to assess whether unmeasured variables could have affected our mediation estimates, showed that for reading comprehension, in NCDS, the indirect effect is robust; only unmeasured confounders highly correlated with the mediator and outcome (ρ = .68) would explain away the indirect effect. For lexical knowledge, smaller correlations with hypothetical confounders (ρ = .33 for BCS) would suffice to render the indirect effect non-significant; the indirect effect for MCS non statistical significant. CONCLUSIONS: Birth weight affects oral and written language skills (lexical knowledge and reading comprehension) in late adolescence via verbal cognition in early adolescence in two cohorts born in 1958 and 1970, but not in a cohort born at the turn of the millennium. These indirect effects were stronger than the direct effects and are unlikely to be explained by unmeasured confounders when the outcome involves complex skills such as reading comprehension.

Adapted version of the pubertal development scale for use in Brazil

ABSTRACT OBJECTIVE To determine whether scores in an adapted version of the self-assessment Pubertal Development Scale into Portuguese match those from the gold standard in pubertal development (Tanner scale). METHODS This was a cross-sectional study with a convenience sample of 133 children and adolescents aged nine to 17 years (59 males; mean age of 13 years and six months, with standard deviation = 25 months). Youngsters completed the Pubertal Development Scale and were then examined by specialists in adolescent medicine. RESULTS Exact absolute agreement of pubertal stages were modest, but significant associations between measures (correlation; intra-class correlation coefficients of consistency) showed that the Pubertal Development Scale adequately measures changes that map onto pubertal development determined by physical examination, on par with international publications. Furthermore, scores obtained from each Pubertal Development Scale question reflected adequate gonadal and adrenal events assessed by clinical ratings, mostly with medium/high effect sizes. Latent factors obtained from scores on all Pubertal Development Scale questions had excellent fit indices in Confirmatory Factor Analyses and correlated with Tanner staging. CONCLUSIONS We conclude that self-assessment of body changes by youngsters using the Portuguese version of the Pubertal Development Scale is useful when estimates of pubertal progression are sufficient, and exact agreement with clinical staging is not necessary. The Pubertal Development Scale is, therefore, a reliable instrument for use in large-scale studies in Brazil that aim at investigating adolescent health related to pubertal developmental. The translated version and scoring systems are provided.