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A positive association has been found between physical activity (PA) and student mental wellbeing (SMW). This association has been mainly explored in secondary school and university students. Studies in vocational education and training (VET) are lacking, while VET students could especially benefit from exploring this association since research shows that VET students, who often come from low socioeconomic status (SES) households, are prone to low SMW. Low SMW can result in higher school dropout rates and long-term negative effects, such as unemployment, social exclusion, and impoverishment. The aim of the current study was to explore the association between total PA and different physical activity behaviors {PABs, i.e., moderate to vigorous physical activity (MVPA), light physical activity (LPA), and sedentary behavior (SB)}, and SMW in the VET setting. In this cross-sectional observational study, students wore an ActivPAL3™ accelerometer for 7 consecutive days to measure PAB. SMW was assessed using the Center for Epidemiologic Studies Depression Scale (CES-D) and the Rosenberg self-esteem questionnaire (RSE). Complete data for the analyses were obtained from 85 students. Multiple regression analyses showed a significant positive association between total PA and self-esteem and a significant negative association between total PA and depressive symptoms. Taking different PA intensities into account, there was a significant positive association between LPA and self-esteem and a significant negative association between LPA and depressive symptoms. No significant associations were found between MVPA and the outcome measures, although the associations were aligned with the findings for LPA. High levels of SB were significantly associated with low self-esteem; however, the association between SB and depressive symptoms was not significant. The significant positive associations between LPA and SMW and the negative association between SB and self-esteem indicate that decreasing SB and increasing LPA could contribute to improve SMW. Future research should determine if these are causal relationships.

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Although iron homeostasis is essential for brain functioning, the effects of iron levels on cognitive performance in older individuals have scarcely been investigated. In the present study, serum iron parameters and hemochromatosis (HFE) C282Y genotype were determined in 818 older individuals who participated in a 3-year randomized, placebo-controlled double-blind trial examining the effects of folic acid on carotid intima-media thickness. All participants had slightly elevated homocysteine levels and were vitamin B12 replete. Cognitive functioning was assessed at baseline and after 3 years by means of a neuropsychological test battery. At baseline, increased serum ferritin was associated with decreased sensorimotor speed, complex speed, and information-processing speed and increased serum iron was associated with decreased sensorimotor speed. Cognitive performance over 3 years was not associated with HFE C282Y genotype or iron parameters. In conclusion, serum iron parameters do not show a straightforward relationship with cognitive functioning, although elevated iron levels may decrease cognitive speed in older individuals susceptible to cognitive impairment

Purpose: Physical activity (PA) and sedentary behavior (SB) seem to have respectively beneficial and detrimental effects on school performance, but evidence for a causal relationship in vocational education and training (VET) students is lacking. This is surprising, as VET students (±16-20 years) stand to benefit because the prefrontal cortex is developing during this age and is therefore sensitive to PA/SB interventions. Furthermore, students in VET have low activity levels in general, meaning enhanced PA/SB behavior could lead to improvement on cognition and learning. The goal of this project is investigating causal effects of PA/SB interventions on a variety of learning performance measures in VET students. Depending on the kind of intervention and the potential mechanisms underlying acute, short-term, or long-term effects, outcome measures vary from specific effects on cognition, to more general effects on school performance, and vital citizenship/employeeship. Methods: In four closely interlinked studies we investigate the causal effects of ‘sedentary behavior repression interventions’ on cognition, school performance, and 21st century skills in VET students. Study 1 (observational) elucidates habitual, objectively measured PA patterns of VET students and their potential association with cognitive performance, school performance, and proxies of vital citizenship and employeeship. Studies 2 and 3 (fundamental) investigate acute interventions in randomized controlled experiments in school settings, controlling for study discipline (physically active versus sedentary disciplines) to determine possible causal effects of PA/SB interventions on cognitive performance and proxies of vital citizenship and employeeship and their underlying mechanisms. Study 4 (ecological experiment) is a long-term intervention developed for the VET setting based on results from the first three studies and literature. Cognition is tested by the Stroop Test, Symbol Digit Modalities Test, and N-back task. School performance is operationalized as scores on Dutch and mathematics; absenteeism/dropout; and the Motivated Strategies for Learning Questionnaire. Vital employeeship/citizenship is measured as collaboration and creativity (GAU, divergent thinking). Where applicable habitual daily activity is measured by accelerometry. Results/Conclusions: Besides scientific output, we deliver tailor-made PA/SB advice and programs for VET students and teachers, taking into account their interests, needs, and possibilities. Furthermore, PHIT2LEARN produces educative materials for students, parents, and teachers.

Inaugural address

Poster presentation at: International Society for the Study of Fatty Acids and Lipids. Sep. 5-9, 2016, Cape Town, South Africa.

Presentation at: International Society for the Study of Fatty Acids and Lipids. Sep. 5-9, 2016, Cape Town, South Africa.

Poster presentation at: 5th Mind-Body Interface International Symposium. Oct. 20-21, 2015, Taichung, Taiwan

Uit onderzoek bij kinderen, adolescenten en studenten in traditioneel onderwijs blijkt doeloriëntatie een goede voorspeller van studiesucces. Bij volwassen studenten, en specifiek in het afstandsonderwijs, is hier echter nauwelijks onderzoek naar gedaan, terwijl deze doelgroep steeds belangrijker wordt. In huidig onderzoek is daarom gekeken naar de toegevoegde voorspellende waarde van doeloriëntatie op studiesucces in het volwassen afstandsonderwijs. Resultaten na 7 maanden studeren laten zien dat een mastery approach oriëntatie een negatieve voorspeller is van studiesucces. Verklaringen voor dit resultaat worden bediscussieerd. Tijdens de ORD zullen tevens resultaten na 14 maanden studeren worden gepresenteerd.Paper presentation at the Onderwijs Research Dagen 2015 (Leiden, the Netherlands)

An important part of learning performance is influenced by individual characteristics. One of those are the environmental influences determined by lifestyle. We call these influences biological lifestyle factors (BLFs). Physical activity, sleep and nutrition are such BLFs and they contribute to brain health, cognitive performance and learning performance in traditional education in children and adolescents. Little research, however, has been conducted concerning these BLFs in adults participating in distance education, despite that this type of education is more and more in favor because of the freedom it offers that allows combining it with the demanding work life, family responsibilities (e.g., a partner and/or children) and the need for ongoing development in adult life. Knowledge on how lifestyle could contribute to learning performance in adults is highly desirable as it could increase the success of adults participating in distance education. Besides, advice on lifestyle changes are relatively cheap interventions of which benefits could be substantial (Ribeiro & Stickgold, 2014). Maintaining a healthy lifestyle does not only result in a better physical and mental health state (Busch, Van Stel, Schrijvers, & de Leeuw, 2013), but also leads to better cognitive performance (Small et al., 2006). Research indicates that a healthy lifestyle is beneficial for cognition and learning, as suggested by research in the domain of physical activity (PA) (e.g., Hillman, Kamijo, & Scudder, 2011), sleep (e.g., Dewald, Meijer, Oort, Kerkhof, & Bögels, 2010; Philip et al., 2012) and nutrition (e.g., Burkhalter & Hillman, 2011; Deliens, Clarys, De Bourdeaudhuij, & Deforche, 2013). These examples provide the theoretical framework for the execution of this PhD project as PA, sleep and nutrition are all three factors that influence the body in a biological way. They exert influence on the regulation of the body’s physiological parameters and the subsequent processes. We will not go into detail on these underlying processes in this proposal because of briefness, but we refer to the following literature (cf., Gómez-Pinilla, 2008; van Praag, 2009; Winter et al., 2007; Wright et al., 2013). These, by lifestyle induced, physiological changes influence processes among which are synaptic pruning, synaptic plasticity and neuronal proliferation. These all contribute to brain plasticity, which is believed to be the basis for better cognitive and learning performance (e.g., Barenberg, Berse, & Dutke, 2011). This led us to investigate the following main research questions in an educational setting different than traditional education for children, namely adult distance education: What are the characteristics of adult distance education with respect to dropout and success? What is the relation(s) between behavior on BLFs on the one hand and cognition and learning performance on the other? The objectives of the PhD project were: (1) to elaborate on the relation of the variables within each BLF with learning performance, but also combining these relations into one model predicting learning performance; (2) to elaborate on the relation of the variables within each BLF with cognitive performance, but also combining these relations into one model predicting cognitive performance; (3) to investigate whether cognitive performance was a mediator in the relation between the BLFs and learning performance. The research proposed to be presented here, stems from a PhD project that will be finished at the time of the conference. The results from the first five, already available, empirical research articles will be presented in a concise but clear manner. One more research article is expected to follow in the future and will most likely be available at the conference and included in the paper presentation.

Citizen science, scientific research conducted by non-specialists, has the potential to facilitate biomedical research using available large-scale data, however validating the results is challenging. The Cell Slider is a citizen science project that intends to share images from tumors with the general public, enabling them to score tumor markers independently through an internet-based interface. From October 2012 to June 2014, 98,293 Citizen Scientists accessed the Cell Slider web page and scored 180,172 sub-images derived from images of 12,326 tissue microarray cores labeled for estrogen receptor (ER). We evaluated the accuracy of Citizen Scientist's ER classification, and the association between ER status and prognosis by comparing their test performance against trained pathologists. The area under ROC curve was 0.95 (95% CI 0.94 to 0.96) for cancer cell identification and 0.97 (95% CI 0.96 to 0.97) for ER status. ER positive tumors scored by Citizen Scientists were associated with survival in a similar way to that scored by trained pathologists. Survival probability at 15 years were 0.78 (95% CI 0.76 to 0.80) for ER-positive and 0.72 (95% CI 0.68 to 0.77) for ER-negative tumors based on Citizen Scientists classification. Based on pathologist classification, survival probability was 0.79 (95% CI 0.77 to 0.81) for ER-positive and 0.71 (95% CI 0.67 to 0.74) for ER-negative tumors. The hazard ratio for death was 0.26 (95% CI 0.18 to 0.37) at diagnosis and became greater than one after 6.5 years of follow-up for ER scored by Citizen Scientists, and 0.24 (95% CI 0.18 to 0.33) at diagnosis increasing thereafter to one after 6.7 (95% CI 4.1 to 10.9) years of follow-up for ER scored by pathologists. Crowdsourcing of the general public to classify cancer pathology data for research is viable, engages the public and provides accurate ER data. Crowdsourced classification of research data may offer a valid solution to problems of throughput requiring human input. Cell Slider is supported by funding from Cancer Research UK. The individual studies were supported by grants from: Cancer Research UK (C490/A10124, C490/A16561), Dutch Cancer Society (NKI 2007-3839 and 2009-4363), the NIHR Biomedical Research Centre at the University of Cambridge, Yorkshire Cancer Research (S295, S299, S305PA), Red Tematica de Investigacion Cooperativa en Cancer, Fondo de Investigacion Sanitario (PI11/00923 and PI081120). The Human Genotyping-CEGEN Unit (CNIO) is supported by the Instituto de Salud Carlos III and the ESTHER study was supported by the Baden Wurttemberg Ministry of Science, Research and Arts. Sí

In deze studie werd de associatie onderzocht tussen objectief gemeten fysieke activiteit en schoolverzuim door ziekte in adolescenten. Daarnaast werd gekeken of er een relatie was tussen de norm gezond bewegen voor kinderen en adolesenten en gezondheid.

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The association between LCPUFA during pregnancy and at birth and academic achievement (arithmics, spelling and reading) at 7 years of age.

In this study, associations between objectively measured active commuting to school and cognitive performance and academic achievement in Dutch adolescents were investigated. Active commuting to school was found to be positively associated with executive functioning in adolescent girls.

Poster presentation at the annual meeting of the International Society for Behaviour on Nutrition and Physical Activity, San Diego, United States of America.

Physical activity and sedentary behavior appear to be related to learning outcomes in children and to cognition across the whole lifespan. Research in adults, concerning physical activity and sedentary behavior and their relationship with learning outcomes, is not apparent. Therefore, we investigated if and how they are related in adults participating in distance education. The study was executed among Open University (NL) students in a cross-sectional survey-research. Opposed to our hypothesis physical activity was a negative predictor for learning outcomes. Possibly, time spent on physical activity in this specific group of students could detract from the time they spent on learning, as it is likely that their spare time is limited. Also, opposed to our hypothesis, sedentary behavior was positively associated with learning outcomes. As spare time is likely to be scarce it could be that time spent learning adds to the time spent sitting, as it is highly likely that most students will study sitting. Thus, possibly resulting in sedentary behavior being a positive predictor for learning outcomes. As expected, physical activity and sedentary behavior appeared to be each independent and separate constructs as they both added uniquely to the regression model. These results ask for more elaboration on the exact effects of physical activity and sedentary behavior on learning in adults.

Presentation of the associations between physical activity and cognitive performance, and academic achievement in adolescents. Physical activity levels were measured in 440 secondary school students during one full week using accelerometers.

As our current knowledge society is changing very rapidly, aging of knowledge and skills is going faster. To keep up with these developments, it is important being able to learn on a higher age. Factors playing a significant role in being a successful learner can have psychological origins. The association between psychological factors and academic performance is well established for children, adolescents, and college students in traditional education. However, evidence of associations between these factors and study success for adult students in distance education is lacking. In the present study, the association between several psychological factors (e.g. affect, test anxiety, goal orientation, learning strategies) and study success for adult students in distance education are investigated. Approximately 2000 students of the Open University will participate in this large longitudinal study, by filling out an online questionnaire and three online neuropsychological tests at baseline. There will be a follow up after six and twelve months. Data collection of baseline takes place September 2012 till September 2013. During EARLI 2013 preliminary results will be shown. The results of this study may provide insight into factors associated with study success in adult students. Based on these results effective learning strategies can be developed in order to optimize the current curriculum.

As our current knowledge society is changing very rapidly, aging of knowledge and skills is going faster. To keep up with these developments, it is important being able to learn on a higher age. Factors playing a significant role in being a successful learner can have psychological origins. The association between psychological factors and academic performance is well established for children, adolescents, and college students in traditional education. However, evidence of associations between these factors and study success for adult students in distance education is lacking. In the present study, the association between several psychological factors (e.g. affect, test anxiety, goal orientation, learning strategies) and study success for adult students in distance education are investigated. Approximately 2000 students of the Open University will participate in this large longitudinal study, by filling out an online questionnaire and three online neuropsychological tests at baseline. There will be a follow up after six and twelve months. Data collection of baseline takes place September 2012 till September 2013. During EARLI 2013 preliminary results will be shown. The results of this study may provide insight into factors associated with study success in adult students. Based on these results effective learning strategies can be developed in order to optimize the current curriculum.

An increasing amount of research supports a positive association between physical activity and cognitive performance or academic achievement. The majority of these studies focused on children or older adults, while less is known about these associations in adolescents. Moreover, in studies on the associations between physical activity and cognitive performance / academic achievement in adolescents, questionnaires (i.e. self-report) were used to measure physical activity. This subjective measure of physical activity has been found to have several limitations, such as social desirability and recall bias. Therefore, associations between objectively measured physical activity and cognition / academic achievement in Dutch adolescents, controlling for relevant covariates, were investigated in this study.

This is the reviewed abstract for the ISBNPA conference proposal for a poster presentation

Gezien de snelle veranderingen in onze huidige kennismaatschappij speelt veroudering van kennis en vaardigheden een steeds grotere rol. Kunnen leren op een hogere leeftijd wordt belangrijker. Determinanten voor succesvol leren kunnen van psychologische oorsprong zijn. Uit onderzoek bij kinderen, adolescenten en studenten in traditioneel onderwijs blijkt doeloriëntatie een goede voorspeller van academisch succes. Bij volwassen studenten in niet-traditioneel onderwijs is hier nog weinig onderzoek naar gedaan. In huidig onderzoek wordt daarom gekeken naar welke doeloriëntatie door volwassen studenten in afstandsonderwijs gehanteerd wordt, en hoe dit samenhangt met studiesucces. Tijdens de ORD zullen de eerste resultaten (N = 574) gepresenteerd worden.

Life expectancies keep rising as our society develops. Changes in our knowledge economy are fast and as a result the value of personal knowledge and experience diminishes at a high rate. This leads to an ongoing demand for employees to develop their knowledge and experience far into adult age. However, the ability to learn decreases over time. Research shows that biological lifestyle factors can possibly influence the ability to learn. Probably, this is partly caused as cognition is a key condition for normal learning and cognition can be influenced by biological lifestyle factors. Three biological lifestyle factors that are associated with learning, study success, academic achievement, and/or cognition are the focus of this study. These biological lifestyle factors are physical activity, sleep, and nutrition. Research into these biological lifestyle factors with regard to study success in adults is lacking. Research so far has focused on primary, secondary, and university education, and is usually targeted on traditional education. The goal of this study is to gain insight in the associations between biological lifestyle factors and study success in adults participating in distance education. A large cross-sectional study will offer more information on how these biological lifestyle factors are associated with study success and cognition. Also, the associations between the biological lifestyle factors and subjective factors (i.e. life satisfaction and health related quality of life) will be evaluated. The goal of this study is to gain insight into the determinants of study success in adult distance learners. Expected is that healthy lifestyles will be positively associated with study success. The results will offer possibilities to develop tailored strategies to enhance study success of students in adult education.

As our current knowledge society is changing very rapidly, aging of knowledge and skills is going faster. To keep up with these developments, it is important being able to learn on a higher age. Factors playing a significant role in being a successful learner can have biological and psychological origins. In present research, the focus will be on psychological determinants. The association between psychological factors (e.g. e.g. test anxiety, stress, learning strategies) and academic performance is well established for children, adolescents, and college students in traditional education. However, evidence of associations between these factors and study success for adult students in distance education is lacking. In this study, we investigate the association between several psychological factors and study success for adult students in distance education. Approximately 2000 students of the Open University will participate in this large cross-sectional study, by filling out an online questionnaire an three online neuropsychological tests. Data collection will take place September 2012 till September 2013. The results of this study may provide insight into factors associated with study success in adult students. Based on these results effective learning strategies are developed in order to optimize the current curriculum.

This cross sectional study showed that physical activity is negatively associated with academic achievement and not significantly associated with cognitive performance in adolescents. Roundtable presentation at ICO Fall School 2012, Girona, Spain.

Since hypertext learning environments (HLE) are widely used in education, it is important to study the effects and consequences of its use. Earlier research suggests that the outcomes of learning based on hypertext environments, depends on learner characteristics in conjunction hypertext specific features. Since the variety in interfaces is enormous, students are challenged to develop new methods of wayfinding for each HLE. It is therefore important to develop interfaces that facilitate learning as much as possible. In this paper a user characteristic (sex) and a hypertext feature (navigational support) are studied. Preliminary results show that there is no difference in sex or navigational support regarding task performance.

How well do executive function tests and questionnaires predict school performance in healthy adolescents? This was investigated in 173 healthy adolescents aged 12-­18 years who study at pre-university education level (in Dutch: vwo). Executive functions were measured with the D-­KEFS subtests Sorting Test and Tower Test, and with the BRIEF-­SR. School performance was measured with end of term grades for Dutch, English and mathematics.

Mensen in onze samenleving worden steeds ouder, daarom wordt formeel leren tijdens volwassenheid steeds belangrijker. Er is weinig bekend over de invloed die verschillende factoren op succesvol formeel levenslang leren hebben tijdens volwassenheid. Het is belangrijk te weten hoe psychologische en biologische factoren het leren beïnvloeden tijdens volwassenheid aangezien grote verschillen bestaan in leefstijl tussen mensen. Daarnaast is het belangrijk te weten hoe deze factoren onderling met elkaar samenhangen. Een grote observationele studie waarin de determinanten van succesvol formeel levenslang leren worden onderzocht zal hier meer inzicht in geven. Dit leidt mogelijk tot op maat gemaakte strategieën waarmee volwassenen hun academisch succes kunnen verhogen. Tevens leidt dit mogelijk tot een succesvolle verouderende populatie, aangezien leren en cognitieve veroudering nauw met elkaar verbonden zijn. De psychologische factoren vormen onderdeel van een ander voorstel.

In onze steeds ouder wordende populatie wordt levenslang leren steeds belangrijker. Echter, bij volwassenen en ouderen is er, in tegenstelling tot bij kinderen en adolescenten, weinig onderzoek gedaan naar factoren die geassocieerd zijn met succesvol formeel leren en de wijze waarop deze factoren met elkaar samenhangen. Een grootschalig observationeel onderzoek onder 2000 volwassen masterstudenten aan de Open Universiteit van Nederland zal een eerste stap zijn om dit te onderzoeken.

Healthy cognitive aging is thought to impact most heavily on episodic memory [1]. However, changes in episodic memory prior to the age of 60 are more controversial than changes in older adults [2]. Furthermore, cognitive decline already present in middle age may not yet manifest in behavior due to the action of neural compensation processes that preserve performance at the behavioral level. Therefore, fMRI can provide valuable insights into age-related changes present in middle age [3]. It is also important to determine the extent to which middle-aged adults must compensate for the effects of cognitive aging in order to maintain performance not just in the short-term, but following sustained, fatigue inducing task performance likely, for example, to be commonly encountered during the workday. Therefore, in the current study, each participant was tested twice: once following a fatiguing condition involving the sustained performance of cognitively demanding tasks and once following a less demanding baseline condition.At baseline, activation was greater, primarily in PFC regions, in middle-aged compared to young adults. This suggests increased exertion of top-down cognitive control in middle-aged adults during successful encoding. In the fatigue condition, activation differences between the two age groups were no longer apparent. Activation in both age groups, but particularly the middle-aged group, decreased in comparison to baseline activation. Therefore, in a state of induced fatigue, middle-aged adults no longer showed greater exertion of cognitive control than young adults, and instead showed activation changes suggestive of an exhaustion of cognitive resources.

Learning abilities have already started to decline in middle age3. However, middle-aged adults are commonly required to continue to maintain performance in fulltime employment. We investigated whether the ability of middle-aged adults to maintain performance despite the effects of cognitive aging comes at the cost of increased cognitive fatigue. Functional MRI studies in patients with disorders characterised by fatigue, such as Multiple Sclerosis3 and Chronic Fatigue Syndrome4, have shown that, although patients could maintain task performance comparable to healthy participants, their performance was associated with increased and more dispersed brain activation. This finding has been attributed to the exertion of greater cognitive effort by patients which, consequentially, has been suggested to underlie their experience of increased cognitive fatigue. Behavioural studies have shown that cognitive fatigue symptoms can be induced in healthy participants by the prolonged performance of cognitively demanding tasks5. In the present study we used fMRI to examine verbal learning related brain activation in young and middle- aged adults following a control intervention and following a fatigue inducing intervention. Conclusions: 1. Middle-aged maintained comparable verbal learning performance to young, and did not indicate greater feelings of subjective fatigue. 2. Middle-aged showed greater activation than young in areas associated with cognitive control and attentional effort following the fatigue intervention during encoding, but not during recognition. 3. Greater subjective fatigue was associated with decreased activation in the left DLPFC in both age groups during encoding, but in young participants only during recognition. 4. It is suggested that middle-aged responded to the increased demands of verbal recognition by switching to more automatic processing.

Onderzoek bij ouderen heeft aangetoond dat lichamelijke activiteit een positief effect heeft op cognitieve prestaties. Bij adolescenten is weinig (objectief) onderzoek uitgevoerd. Middels deze studie wordt op een objectieve manier onderzocht welke associatie er is tussen oa. sporten, fietsen naar school en slapen en de schoolprestaties van adolescenten.

Onderzoek bij ouderen heeft aangetoond dat lichamelijke activiteit een positief effect heeft op cognitieve prestaties. Bij adolescenten is weinig (objectief) onderzoek uitgevoerd. Middels deze studie wordt op een objectieve manier onderzocht welke associatie er is tussen oa. sporten, fietsen naar school en slapen en de schoolprestaties van adolescenten.

The aim of our research is to implement and evaluate a recently developed neuropsychological intervention in a school setting.

BackgroundUniversity students often exhibit high levels of sedentary behavior that is negatively associated with cognition and mood. On the other hand, light-intensity physical activity (LIPA) may improve cognitive performance and mood. Therefore, this study investigated the acute effect of LIPA breaks during prolonged sitting on attention, executive functioning, and mood. MethodsA randomized crossover design was used in this study. In total, 21 healthy adults (15 women, age = 24 +/- 3 years, BMI = 23 +/- 2 kg/m(2)) completed three prolonged sitting conditions: (1) without a demanding cognitive task (SIT), (2) with a demanding cognitive task (COGN), and (3) with every 25 min sitting interrupted by a 5-minute walk (INTERRUPT). Attention, executive function (response inhibition, task shifting, and working memory updating), and mood were assessed before and after each condition. ResultsLinear mixed models analyses showed that prolonged sitting frequently interrupted by LIPA (INTERRUPT) or with cognitively demanding activities (COGN) significantly improved task shifting compared to SIT. However, INTERRUPT did not significantly improve task shifting compared with COGN. No significant acute effects on attention, response inhibition, working memory updating, or mood were found. ConclusionsFrequent LIPA breaks or cognitively demanding activities have a selective, acute positive impact on one aspect of cognitive performance compared to idle sitting. No evidence was found that LIPA breaks have an acute improvement in attention, executive function, and mood compared to sitting with cognitive loading. To further investigate the effect of PA on cognitive performance, it is necessary to consider cognitive loading and control for the cognitive activity during sitting in the experimental design. This study was undertaken at the Maastricht University without external funding. YW was involved in the design of the study, carried out the data collection, performed the data analysis, interpreted the results, and drafted the manuscript; HHCMS, RHMDG, PWMVG, and BOE were involved in the design of the study and the interpretation of the results; BW contributed to the statistical analysis and the interpretation of the results. All the authors contributed to the writing of the manuscript. All the authors have read and agreed to the final version of the manuscript. The authors declare that they have no competing interests. The authors thank the volunteers who participated in this study.

BACKGROUND: University students sit too much, which is detrimental to their physical and mental health. Academic schedules, including scheduled education time and self-study time, may influence their physical activity behaviors. OBJECTIVES: To investigate (1) the association between scheduled education time and students' physical activity levels during weekdays; (2) the association between self-study time and students' physical activity levels during the weekdays and weekends. METHODS: 126 (68 Maastricht University (UM); 58 KU Leuven (KUL)) first-year undergraduate students in biomedical sciences (mean ± SD age: 19.3 ± 1.0, BMI: 22.0 ± 3.0, 17% men, 83% women) completed a demographics questionnaire and reported their academic activities with a 7-day logbook. Furthermore, their physical activity behavior was measured with the activPAL monitor for 7 days. Linear mixed models were used to examine the associations between university (UM versus KUL), academic activities (scheduled education time and self-study time), and students' activity levels. RESULTS: During weekdays, each hour of scheduled education time per day was significantly associated with a 1.3 min decrease of moderate to vigorous physical activity (MVPA) per day. Scheduled education time was not significantly associated with the sedentary time, light-intensity physical activity (LPA), and active sedentary behavior ratio. Each hour of self-study per day was significantly associated with 8 min more of sedentary time per day, 6 min less LPA per day, and 1.3 min less MVPA per day. Self-study time was not significantly associated with active sedentary behavior ratio. During the weekend, each hour of self-study time per day was associated with an additional 17.8 min of sedentary time per day and a reduction of 15.2 min of LPA per day. Self-study time was not significantly associated with the time spent doing MVPA and active sedentary behavior ratio. CONCLUSIONS: It could be more effective to change students' physical activity behaviors during self-study than during scheduled education time. Therefore, offering a study environment that reduces sedentary behavior and promotes light-intensity physical activity, is crucial. ispartof: INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH vol:20 issue:2 ispartof: location:Switzerland status: published

Background: It has been suggested that prenatal exposure to n-3 long-chain fatty acids protects against asthma and other allergy-related diseases later in childhood. The extent to which fish intake in pregnancy protects against child asthma and rhinitis symptoms remains unclear. We aimed to assess whether fish and seafood consumption in pregnancy is associated with childhood wheeze, asthma and allergic rhinitis. Methods: We pooled individual data from 60 774 mother-child pairs participating in 18 European and US birth cohort studies. Information on wheeze, asthma and allergic rhinitis prevalence was collected using validated questionnaires. The time periods of interest were: infancy (0-2 years), preschool age (3-4 years), and school age (5-8 years). We used multivariable generalized models to assess associations of fish and seafood (other than fish) consumption during pregnancy with child respiratory outcomes in cohort-specific analyses, with subsequent random-effects meta-analyses. Results: The median fish consumption during pregnancy ranged from 0.44 times/week in The Netherlands to 4.46 times/week in Spain. Maternal fish intake during pregnancy was not associated with offspring wheeze symptoms in any age group nor with the risk of child asthma [adjusted meta-analysis relative risk (RR) per 1-time/week = 1.01, 95% confidence interval 0.97-1.05)] and allergic rhinitis at school age (RR = 1.01, 0.99-1.03). These results were consistently found in further analyses by type of fish and seafood consumption and in sensitivity analyses. Conclusion: We found no evidence supporting a protective association of fish and seafood consumption during pregnancy with offspring symptoms of wheeze, asthma and allergic rhinitis from infancy to mid childhood. This work was supported by the European Community’s Seventh Framework Program [EU- FP7- HEALTH-2009-single-stage-241604]. Details of funding per cohort are available at IJE online.

A number of studies show that essential fatty acids and their longer chain derivatives (longchainpolyunsaturated fatty acids, LCPUFA), play a significant role in brain functioning,because they are important constituents of the cell membrane. A sufficient LCPUFA statushas been related to better cognitive functioning of both children and adults, as well as lesscognitive decline in elderly. The relationship between LCPUFA and school performancehas been studied to a lesser extent. In adults, a beneficial LCPUFA status has been relatedto less depression.Because the brain of children and adolescents is still profoundly developing, it can bepresumed that LCPUFA might be especially important, as building blocks, in these periodsof development. The goal of this dissertation was to study the relationship betweenLCPUFA and school performance in children, and to study the influence of LCPUFAsupplementation on cognition and mental well-being in adolescents.In Chapter 1 a general and theoretical introduction to this dissertation is provided,information on the following topics is given: fatty acid metabolism, importance of intake ofLCPUFA, in what foods LCPUFA are present, and the advantages of krill oilsupplementation (the form of supplementation used in the studies in this dissertation) overfish oil supplementation. Next, six possible mechanisms in which LCPUFA can possiblyinfluence brain functioning are elaborated upon. Then the brain development from birththroughout childhood and adolescence is explained. To finish, theoretical backgroundinformation on the outcome variables investigated in this dissertation (i.e., schoolperformance, cognition, and mental well-being) is provided.In this dissertation data, collected in two studies, were used to answer the goalsdescribed above. In Chapter 2 an overview of one of these studies, the MaastrichtEssential Fatty Acids Birth Cohort (MEFAB cohort) is given. The MEFAB cohort was setup in 1989 to study the change in fatty acid concentrations during pregnancy and how thisrelates to the fatty acid concentrations of the neonate. Moreover, the association betweenthe fatty acid concentrations and a number of birth outcomes (e.g., weight, length and headcircumference) was assessed. The MEFAB cohort has three follow-up studies at age 4, 7and 12 of the child. Data on cognitive development, asthma/atopy, growth, andcardiovascular disease risk factors among others, were collected. Besides the description ofthe design, the main earlier findings of the MEFAB cohort are discussed.In Chapter 3 data from the MEFAB cohort is used to assess the associations betweenmaternal LCPUFA concentrations during pregnancy, at birth, and child’s LCPUFAconcentration at age 7, and school performance at age 7. Analyses with correction forcovariates showed a negative association between maternal DHA concentration duringpregnancy, maternal and child’s DHA concentration at birth, and child’s arithmetic score atage 7. Moreover, maternal Osbond acid (ObA) levels at 22 and 32 weeks of pregnancy, andObA level in umbilical cord blood plasma were positively associated with arithmetic scoreat age 7. This last finding confirms the negative relationship between DHA status andarithmetic scores, as ObA is a deficiency marker of DHA (i.e., higher ObA levels reflectlower DHA levels). In contrast, child’s DHA concentration at age 7 was positivelyassociated with both the reading and spelling score at age 7.Chapter 4 concerns the design of the second study, Food2Learn. In Chapter 4 theunique characteristics and the rationale behind the research design are presented.Food2Learn was a double-blind, randomised, placebo controlled intervention trial inadolescents (age 13–15 years) attending lower general secondary education. The goal of Food2Learn was to determine the influence of increasing Omega-3 Index (O3I) oncognitive functioning, academic achievement and mental well-being of typically developingadolescents. Unique characteristics of Food2Learn are among others the fact that:participants were recruited based on a low O3I at baseline, students were asked to take krilloil capsules at dinner time to increase LCPUFA absorption, a personalized krill oil doseadjustment was planned, and the study focused on students of a lower educational level.In Chapters 5 and 6, baseline results of Food2Learn are presented. In Chapter 5 theassociations between baseline O3I of the participants of Food2Learn and scores on thecognitive measures are reported. Analyses revealed a significant positive associationbetween the O3I and score on the Letter Digit Substitution Task (i.e., measure forinformation processing speed). Moreover, a significant negative association between theO3I and errors of omission on the D2 (i.e., measure for inattention/impulsivity) wasshown. Thus, participants with a higher O3I had a higher information processing speed,and less inattention/impulsivityIn Chapter 6 the associations between baseline O3I and other fatty acids (DHA,eicosapentaenoic acid (EPA), arachidonic acid (AA), docosapentaenoic acid (DPA), andObA) and both depressive feelings and self-esteem are reported. Bayesian analyses showeda weak negative association between ObA and depression score, and a weak positiveassociation between ObA and self-esteem score. In other words, more ObA measured inblood corresponded with less depression and more self-esteem. There was no evidence foran association between DHA, EPA, and O3I, and depression and/or self-esteem.In Chapter 7 and 8 the effects of one year of krill oil supplementation on respectivelycognitive measures (chapter 7) and mental well-being measures (chapter 8) are reported.There was no significant effect of krill oil supplementation on either the cognitive measuresor mental well-being measures. The most likely explanation for these non-significanteffects, is the high amount of drop-out and non-adherence with the protocol. Due to theseproblems, it cannot be concluded that a relationship between krill oil supplementation andcognition, and mental well-being does not exist.While executing Food2Learn, there were difficulties with recruiting participants, dropout,and adherence. It was however unknown how common those problems are inLCPUFA supplementation studies in children and adolescents. Therefore, a systematicreview focussing on recruitment, adherence, and drop-out rates in LCPUFAsupplementation studies in children and adolescents was executed in Chapter 9. Problemswith recruitment and drop-out were common in LCPUFA supplementation trials inchildren and adolescents. Techniques to improve recruitment, adherence and dropout rateswere identified in the literature and are reported in Chapter 9 as well.In Chapter 10, the main results of the studies in this dissertation are discussed, andusing an additional literature review, evaluated and put into a broader perspective.To conclude, MEFAB and Food2Learn do not provide conclusive evidence for arelationship between LCPUFA and school performance, cognition and mental well-beingin children and adolescents. However, associations between LCPUFA concentrations andboth school performance, and cognition were found. Future studies should pay attentionto, among other things, objectively measuring LCPUFA concentrations, long-term highdose LCPUFA supplementation, personalised dose adjustment, and focus on adolescence,as this is a period of profound brain development. The relevance for society of bothMEFAB and Food2Learn can be translated into the advice to consume either two servings of fatty fish per week or, based on the literature review in chapter 10, take a supplementwith at least 400mg DHA + EPA per day, as this amount has by all means a positive effecton general health, and possibly a positive effect on brain functioning as well.