Effect of maternal fish oil supplementation during lactation on socioemotional wellbeing and physical activity in 13-year-old children: A randomized clinical trial.

Early dietary long-chain n-3PUFA (n-3LCPUFA) may affect brain development. We investigated if fish oil supplementation of lactating mothers affected socioemotional wellbeing in adolescents in a potentially gender-specific manner. At age 13, we invited 92 children of mothers who completed a randomized trial with 1.5 g/d n-3 LCPUFA or olive oil during the first 4 months of lactation and 48 children of mothers with a high habitual fish intake. Children and parents answered validated questionnaires regarding socioemotional wellbeing and physical activity was monitored by ActiGraph for 7 days. Participation rate was 71%. Univariate correlations between children's and parents' ratings on the individual scales were moderate-strong, but correlations across questionnaires indicated that parents might base their ratings on proxy markers. We found no group differences in self-rated socioemotional outcomes or physical activity. Although the study was small, it was the first follow-up on effects of perinatal n-3LCPUFA supply on socioemotional wellbeing in adolescence.

Maternal exposure to psychosocial job strain during pregnancy and behavioral problems in the 11-year-old children: a Danish cohort study.

Maternal psychosocial stress may impact child neurodevelopment, but little is known regarding psychosocial job strain. We hypothesized high psychosocial job strain during pregnancy was associated with behavioural problems in the 11-year-old children. Mothers in the Danish National Birth Cohort (1996-2002) were included if they worked, provided information on job strain [Karasek's model: high job strain (often job demand/seldom job control) and passive (seldom or sometimes job demands/seldom job control)] during early pregnancy. At the 11-year follow-up, children (N = 30,592), mothers (N = 30,993), and teachers (N = 12,810) responded to the Strength and Difficulties Questionnaire (SDQ), a screening tool for child behaviour. Scores for hyperactivity, conduct, emotional and peer problems were dichotomised [80% (no) vs. 20% (yes)] according to Danish norms (yes/no). Maternal job strain was not associated with behavioural problems with teachers as informants. When assessed by child or mother, high maternal job strain increased risk of child behavioural problems, but risks were more pronounced for mothers in passive jobs [maternal assessment of total difficulties/odds ratio (95% confidence interval): high strain-girls: 1.16 (0.97-1.40); boys: 1.24 (1.02-1.50). Passive girls: 1.43 (1.21-1.68); boys: 1.25 (1.05-1.49)]. This is one of the first studies on this topic. The different types of maternal job strain were partly associated with child behavioural problems at 11 years; more so if mothers worked in passive rather than the hypothesized high strain jobs. Findings showing dependency on informant could not only indicate unmeasured confounding or rater's bias, but also selection in the smaller numbers of teacher informants or different environments of interaction with the children.

Effects of oily fish intake on cognitive and socioemotional function in healthy 8-9-year-old children: the FiSK Junior randomized trial.

BACKGROUND: Long-chain n-3 PUFAs (n-3 LCPUFAs) accrete in the brain during childhood and affect brain development. Randomized trials in children show inconsistent effects of n-3 LCPUFAs on cognitive and socioemotional function, and few have investigated effects of fish per se. OBJECTIVES: We aimed to investigate the effects of oily fish consumption on overall and domain-specific cognitive and socioemotional scores and explore sex differences. METHODS: Healthy 8-9-y-old children (n = 199) were randomly allocated to receive ∼300 g/wk oily fish or poultry (control) for 12 ± 2 wk. At baseline and endpoint, we assessed attention, processing speed, executive functions, memory, emotions, and behavior with a large battery of tests and questionnaires and analyzed erythrocyte fatty acid composition. RESULTS: One hundred and ninety-seven (99%) children completed the trial. Children in the fish group consumed 375 (25th-75th percentile: 325-426) g/wk oily fish resulting in 2.3 (95% CI: 1.9, 2.6) fatty acid percentage points higher erythrocyte n-3 LCPUFA than in the poultry group. The overall cognitive performance score tended to improve by 0.17 (95% CI: -0.01, 0.35) points in children who received fish compared with poultry, supported by n-3 LCPUFA dose dependency. This was driven mainly by fewer errors [-1.9 (95% CI: -3.4, -0.3)] in an attention task and improved cognitive flexibility measured as faster reaction time [-51 ms (95% CI: -94, -7 ms)] in a complex relative to a simple task ("mixing cost"). The fish intervention furthermore reduced parent-rated Strength and Difficulties Questionnaire total difficulties by -0.89 (95% CI: -1.60, -0.18) points mainly due to a -0.63 (95% CI: -1.11, -0.16) points reduction in internalizing problems that was reflected in tendency to a decrease in the overall socioemotional problems score of -0.13 (95% CI: -0.26, 0.01) points. The overall effects were similar in boys and girls. CONCLUSIONS: Oily fish dose-dependently improved cognitive function, especially attention and cognitive flexibility, and reduced socioemotional problems. The results support the importance of n-3 LCPUFAs for optimal brain function and fish intake recommendations in children.The trial was registered at www.clinicaltrials.gov as NCT02809508.

Translation and psychometric validation of a Danish version of the medication-related quality of life scale.

Background Generic and disease specific health-related quality of life scales have been found to be non-responsive to changes in medications in polypharmacy patients. The Taiwanese medication-related quality of life (MRQoL) scale aims to measure the effect of medication use on patients' quality of life. Objective To evaluate the psychometric properties of the Danish translation of MRQoL in a population of patients with polypharmacy. Setting Polypharmacy patients waiting for services at a community pharmacy or hospital in Denmark. Method The original MRQoL included 14 items. It was forward-translated into Danish and backward-translated into Chinese according to a modified translation protocol proposed by Sousa and Rojjanasrirrat et al. The translation was pre-tested, adjusted, and administered to polypharmacy patients. The factor structure was examined using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Internal consistency reliability was evaluated, and criterion validity assessed using the beliefs about medicines questionnaire (BMQ) and SF-12v2. Known-group validity was carried out on age, number of medicines and setting. Main outcome measure Validity of the Danish version of the MRQoL-scale. Results 164 patients completed the questionnaire. EFA of all 14 items resulted in a two-factor structure, accounting for 72.8% of the total variance. The two factors were named "Energy/Concentration" (7 items) and "Feelings/Social" (7 items). Items correlating over 0.80 were removed leaving 11 items (Model 1). This model was further reduced to 8 items (Model 2) based on Cronbach's alpha. CFA confirmed the two-factor structure of both models. Model 2 fitted data without having to define covariations between error terms. Both factors showed high internal consistency reliability (Cronbachs' alpha 0.901-0.932). Ceiling effects were detected for both factors. Criterion validity was demonstrated via its significant correlations with SF-12vs2 subscales (Spearman's rho 0.340-0.353) and BMQ Concern (Spearman's rho - 0.451 to - 0.347). There was a statistically significant difference in relation to total scores of the MRQoL for age and number of drugs taken, indicating known-group validity. Conclusion The Danish translation of the MRQoL instrument showed measurement properties indicating a well-defined two-factor structure with high internal reliability, concurrent criterion validity, and known group validity. However, challenges remain with ceiling effects and efforts should be put into further development of the instrument.

Depression-related distortions in maternal reports of child behaviour problems.

Associations between maternal depression and child behaviour problems may be biased due to depression-related distortions in the maternal reports. In this study, we compared the agreement between maternal, teacher and child ratings of hyperactivity/inattention (H/I), conduct (CD) and emotional (EM) problems measured with the Strengths and Difficulties Questionnaire in a population with depressed and non-depressed mothers. The sample of 12,961 11-year-old children was drawn from the Danish National Birth Cohort. We also examined the association between maternal depression before and during the child's life and child H/I, CD and EM problems when reported by the different informants. Agreement between the informants was assessed with the Bland-Altman limits of agreement (LOA) and associations were analyzed using multiple linear regression models. We found large discrepancies between maternal and teacher ratings of child behavioural problems measured with the SDQ and less discrepancy between maternal and child self-ratings. Better agreement between informants was found in the population of depressed mothers compared to non-depressed mothers for H/I and CD problems, and not for EM symptoms. The LOA for all three subscales were wide in both populations, with the largest intervals ranging from - 6 (Lower LOA) to 3 (Upper LOA) for H/I. Statistically significant associations were found between maternal depression, and child H/I and CD problems when reported by the mother but not the teacher and only by the child, when maternal depression had been present during the child's life. Our findings emphasize the importance of considering each informants' ratings when obtaining ratings from multiple sources.

The Strengths and Difficulties Questionnaire and standardized academic tests: Reliability across respondent type and age.

Exploiting nation-wide data from the Danish National Birth Cohort, we show that children's emotional and behavioral problems measured by the Strengths and Difficulties Questionnaire (SDQ) are closely related to their performance in standardized academic tests for reading and mathematics in sixth grade. The relationship is remarkably linear across the entire distribution for both the total difficulties score and subscale scores of the SDQ; higher scores on the SDQ (more problems) are related to worse performance in academic tests. We assess the similarity across respondent type; parent (child age 7 and 11), teacher (child age 11) and self-reported scores (child age 11), and find that teacher and parent reported scores have very similar slopes in the SDQ-test score relationship, while the child reported SDQ in relation to the academic test performance has a flatter slope.

Danish norms for the Strengths and Difficulties Questionnaire.

INTRODUCTION: The Strengths and Difficulties Ques-tion-naire (SDQ) is a brief well-validated psychometric instrument for assessment of developmental, behavioural and emo-tional problems in children and adolescents. Versions of the questionnaire covering the 2-17-year age range are an-swered by parents and by pedagogues or teachers. Also, a self-report version can be used from the age of 11 years. The SDQ is well-accepted by informants and is increasingly preferred both internationally and in Denmark for research and evaluation purposes. The questionnaire is also well-suited for clinical use, especially in the primary sector. However, no comprehensive set of Danish norms has been available before this study. METHODS: Data from an extensive survey in a Danish municipality was used to generate national norms for SDQ scores. These norms were compared with British and Nordic population data. RESULTS: Across informants, threshold values show some variation with age and often differ between sexes. Therefore, norms are provided both with and without gender stratification. Similarities as well as differences were found between the Danish norms and materials from other countries. The differences may, to some extent, be attributable to methodological issues. CONCLUSION: We expect that the availability of Danish SDQ norms will further stimulate the use of the instrument. FUNDING: TrygFonden provided financial support for the development of Danish SDQ norms. TRIAL REGISTRATION: not relevant.

Exploring correlations between neuropsychological measures and domain-specific consistency in associations with n-3 LCPUFA status in 8-9 year-old boys and girls.

Long-chain n-3 polyunsaturated fatty acids (n-3 LCPUFA) have in some studies been associated with cognitive and socioemotional outcomes in children, but results are inconsistent possibly due to the use of different tests and potential gender-specific effects. The objective of this cross-sectional study was to explore overall patterns in neuropsychological scores as well as correlations between scores within specific domains, and to examine potential gender differences and consistency in associations with n-3 LCPUFA status. In 199 Danish 8-9 year-old children, we performed a large battery of tests and questionnaires on attention, processing speed, executive functions, memory, and socioemotional traits, and measured erythrocyte fatty acid composition. Principal component analyses (PCA) showed that most of the variation in both cognitive performance and socioemotional traits was explained by overall performance, followed by speed-accuracy trade off and externalizing vs. internalizing problems, respectively. Boys had higher speed, lower attention and higher externalizing problem scores than girls. Measures of performance within both processing speed and attention domains correlated moderately, whereas no correlations were found for measures of executive functions apart from some weak correlations for impulsivity. Parent-rated scores for both externalizing and internalizing problems correlated strongly, whereas correlations with child-rated scores were weak. Scores within specific domains did not consistently associate with n-3 LCPUFA, except for processing speed measures which all pointed to faster processing with increased n-3 LCPUFA status. Gender differences in the associations were observed for attention and impulsivity. Child- but not parent-rated internalizing and social problems tended to associate directly with n-3 LCPUFA, supported by increased internalizing problems measured by the PCA component. In conclusion, measures of speed and attention seem to represent these domains in general, whereas single measures of more complex cognitive functions should be interpreted with caution. One approach could be to use multiple tests and create multivariate scores to guide interpretations. Furthermore, the results indicate a need to consider both parent- and child-rated socioemotional scores and gender differences in neuropsychological functions e.g. in investigations of n-3 LCPUFA effects.

Association of Education Outside the Classroom and Pupils' Psychosocial Well-Being: Results From a School Year Implementation.

BACKGROUND: Education Outside the Classroom (EOtC) is a teaching method that is gaining traction, aiming to promote learning and well-being. However, research on the association between EOtC and well-being is limited. METHODS: This quasi-experimental trial involved pupils (9-13 years) from 16 Danish public schools which implemented EOtC in some classes. Pupils (N = 511) from 27 classes were regularly exposed to EOtC (2-7 hours per week), and pupils (N = 120) from 7 parallel comparison classes were much less exposed (less than 2 hours per week). The pupils' psychosocial well-being was measured at the beginning and end of the school year using the Strengths and Difficulties Questionnaire. The results were compared between the groups. RESULTS: Pupils regularly exposed to EOtC showed the greatest improvement in prosocial behavior. Negative associations were seen between EOtC and hyperactivity-inattention and peer problems in pupils of low socioeconomic status (SES). The observed improvements were smaller when the EOtC was spread over a larger number of sessions. Results were independent of sex. CONCLUSIONS: Regular exposure to EOtC was found to promote social well-being, especially for pupils of low SES, and was most beneficial when concentrated in fewer, longer sessions.

Mental health interventions among older adults: A systematic review.

BACKGROUND: The aim of the present study was to conduct a systematic review to identify documented mental health promotion interventions developed and tested among population-based older adults. METHODS: A systematic review based on PRISMA guidelines. The literature was searched in PsycINFO and PubMed between June and September 2016. The Effective Public Health Practice Project tool was used to assess the quality of the included study. RESULTS: In total 53 randomized controlled trial studies qualified for the systematic review. Across studies, three types of common conceptual themes emerged for interventions, including: 1) individual characteristics; 2) content and structure of the interventions; and 3) implementation of the interventions. CONCLUSIONS: No specific interventions could be recommended on the aforementioned basis. We conclude that a number of factors are of central importance for an intervention to have the desired effect. If these factors are considered, mental health can be successfully promoted among older adults.

Parental socioeconomic position and risk of ADHD in offspring: a cohort study of 9648 individuals in Denmark 1976-2013.

The strength of the association between parental socioeconomic position (SEP) and risk of attention-deficit/hyperactivity disorder (ADHD) in offspring is found to vary substantially, perhaps due to the negligence of possible changes in parental life course SEP. The present study investigated the association between parental SEP in adulthood and risk of ADHD diagnosis in offspring and whether parental childhood SEP modified this association. The study population included 9648 live-born singletons followed in the Psychiatric Central Register from birth in 1976-1996 until 2013. Cox regression was used to estimate hazard ratios for ADHD diagnosis according to parental SEP in adulthood. The results showed that low parental SEP in adulthood was associated with higher risk of ADHD diagnosis in offspring, also after adjustment for possible confounders. Thus, offspring of parents with low SEP in adulthood had 4.52 (95% CI 2.81-7.26) times higher hazard of ADHD diagnosis compared with offspring of parents with high SEP in adulthood. Further, parental childhood SEP was found to modify the observed association. Thus, offspring of parents with downward social mobility from childhood to adulthood and offspring of parents with stable low SEP experienced the highest risk of ADHD diagnosis, followed by offspring of parents with upward social mobility, compared with offspring of parents with stable high SEP. The results suggest that it is important to take into account the possibility of social mobility as changes in parental life course SEP from childhood to adulthood seem to influence the risk of ADHD diagnosis in offspring.

Mental health among children of mothers with multiple sclerosis: A Danish cohort and register-based study.

BACKGROUND: Multiple sclerosis is associated with an increased risk of developing physical, cognitive, and mental health problems. Current studies have demonstrated variating outcomes of parental multiple sclerosis mental health problems and their children's mental health development. OBJECTIVE: The purpose of this study was to investigate whether maternal multiple sclerosis is associated with the mental health status of their child. METHODS: Data from the Danish National Birth Cohort (DNBC) were merged with information from the Danish Multiple Sclerosis Registry. Two proxies, total difficulties score and prediction of any psychiatric diagnosis based on the strengths and difficulties questionnaire, were used to measure the mental health status of the children. The two groups were compared using Mann-Whitney and logistic regression analyses. RESULTS: For the total difficulties score the control and exposed group consisted of respectively n = 42,016 and n = 40, and for the prediction of any psychiatric diagnosis respectively n = 16,829 and n = 17. We found no statistically significant association between maternal multiple sclerosis and mental health status on neither of the proxies. CONCLUSION: Maternal multiple sclerosis did not show any association with the mental health status of their children at age eleven. On the contrary, other studies conclude that there is an association between maternal multiple sclerosis and the child's mental health status, one especially mediated by the maternal mental health status.

Psychometric properties of the Danish student well-being questionnaire assessed in >250,000 student responders.

BACKGROUND: Well-being is considered a prerequisite for learning. The Danish Ministry of Education initiated the development of a new 40-item student well-being questionnaire in 2014 to monitor well-being among all Danish public school students on a yearly basis. The aim of this study was to investigate the basic psychometric properties of this questionnaire. METHODS: We used the data from the 2015 Danish student well-being survey for 268,357 students in grades 4-9 (about 85% of the study population). Descriptive statistics, exploratory factor analyses, confirmatory factor analyses and Cronbach's α reliability measures were used in the analyses. RESULTS: The factor analyses did not unambiguously support one particular factor structure. However, based on the basic descriptive statistics, exploratory factor analyses, confirmatory factor analyses, the semantics of the individual items and Cronbach's α, we propose a four-factor structure including 27 of the 40 items originally proposed. The four scales measure school connectedness, learning self-efficacy, learning environment and classroom management. Two bullying items and two psychosomatic items should be considered separately, leaving 31 items in the questionnaire. CONCLUSIONS: The proposed four-factor structure addresses central aspects of well-being, which, if used constructively, may support public schools' work to increase levels of student well-being.

Maternal Caffeine Consumption during Pregnancy and Behavioral Disorders in 11-Year-Old Offspring: A Danish National Birth Cohort Study.

OBJECTIVE: To examine the association between maternal caffeine consumption from coffee and tea during pregnancy and offspring behavioral disorders. STUDY DESIGN: We studied 47 491 children enrolled in the Danish National Birth Cohort between 1996 and 2002. Data on maternal coffee and tea consumption was collected at 15 and 30 weeks of gestation. When the child was 11 years old, the Strength and Difficulties Questionnaire was filled in by children, parents, and teachers. We estimated risk ratios (RRs) for offspring behavioral disorders. RESULTS: At 15 weeks of gestation 3% and 4% of the pregnant women consumed ≥8 cups/d of coffee or tea, respectively. Maternal coffee consumption ≥8 cups/d at 15 weeks of gestation was associated with increased risk of hyperactivity-inattention disorder (RR 1.47; 95% CI 1.18-1.83), conduct-oppositional disorders (RR 1.22; 95% CI 1.01-1.48), and any psychiatric disorder (RR 1.23; 95% CI 1.08-1.40). Maternal tea consumption ≥8 cups/d at 15 weeks of gestation was associated with increased risk of anxiety-depressive disorders (RR 1.28; 95% CI 1.09-1.52) and any psychiatric disorder (RR 1.24; 95% CI 1.11-1.40). An increased risk of hyperactivity-inattention disorder was observed with increasing daily caffeine consumption at 15 weeks of gestation. CONCLUSION: High maternal caffeine consumption from coffee and tea at 15 weeks of gestation was associated with behavioral disorders in 11-year-old offspring. We hypothesize that caffeine exposure may affect the fetal brain and program for behavioral disorders later in life. The fetal brain seems to be more sensitive to caffeine exposure at 15 weeks of pregnancy compared with 30 weeks of gestation.

Early childhood otitis media and later school performance - A prospective cohort study of associations.

INTRODUCTION: Otitis media (OM) is a common disease in childhood and hearing loss (HL) is the most common complication. Prolonged HL may lead to language delay and cognitive difficulties. However, the consequences of HL due to OM are not fully understood. The aim of this study was to determine the possible association between number of OM episodes in childhood and self-rated school performance controlling for potential confounders. METHODS: Prospectively gathered systematic interview data on OM episodes in early childhood and school performance at 11 years of age were obtained from The Danish National Birth Cohort, involving >100,000 individual pregnancies and their offspring. We defined four exposure groups (0, 1-3, 4-6 and ≥7 OM episodes) and assessed general school performance, mathematics and literacy. Possible confounders were recognized à priori and associations were determined using proportional odds regression. RESULTS: Out of 94,745 successful pregnancies, 35,946 children without malformations and their parents completed a questionnaire at age 11 years. No associations were observed between number of OM episodes and school performance, even in children with ≥7 OM episodes. CONCLUSION: This national birth-cohort study did not support the hypothesis that the number of OM episodes in childhood is associated with reduced self-reported school performance in children at 11 years of age.

Correction: Risk Factors of Early Otitis Media in the Danish National Birth Cohort.

[This corrects the article DOI: 10.1371/journal.pone.0166465.].

Risk Factors of Early Otitis Media in the Danish National Birth Cohort.

OBJECTIVE: To assess risk factors of otitis media (OM) in six-months-old children. METHOD: The sample consisted of 69,105 mothers and their children from the Danish National Birth Cohort. The women were interviewed twice during pregnancy and again 6 months after birth. The outcome "one or more" maternal reported episodes of OM at age six months. In total 37 factors were assessed, covering prenatal, maternal, perinatal and postnatal factors. RESULTS: At age six months 5.3% (95% CI 5.1-5.5) of the children had experienced one or more episodes of OM. From the regression analysis, 11 variables were associated with a risk of OM. When a Bonferroni correction was introduced, gender, prematurity, parity, maternal age, maternal self-estimated health, taking penicillin during pregnancy, and terminating breastfeeding before age six months, was associated with a risk of early OM. The adjusted ORs of OM for boys versus girls was 1.30 (95% CI 1.18-1.44). The OR having one sibling versus no siblings was 3.0 (95% CI 2.64-3.41). If the woman had been taking penicillin during pregnancy, the OR was 1.35 (95% CI 1.15-1.58). Children born before 38th gestational week had an increased OR for early OM of 1.49 (95% CI 1.21-1.82). Children of young women had an increased OR of early OM compared to children of older women. Additionally, children of women who rated their own health low compared to those rating their health as high, had an increased OR of 1.38 (95% CI 1.10-1.74). Finally, children being breastfeed less than 6 months, had an increased OR of 1.42 (95% CI 1.28-1.58) compared to children being breastfeed beyond 6 months. CONCLUSION: These findings indicate that prenatal factors are of less importance regarding early OM before the age of six months. Postnatal risk factors seem to pose the main risk of early OM.

Associations between childhood hearing loss and behavioural and academic difficulties: A Danish cohort study.

OBJECTIVE: Negative associations between hearing loss (HL) and behavioural and academic difficulties have been reported. However, most studies are based on small clinical samples. The aim of the present study was to investigate such associations using data from a large-scale non-clinical Danish birth cohort controlling for a large number of relevant confounding factors. METHODS: The study applied data from the Aarhus Birth Cohort's 10-12-year-old follow-up (N = 7599). Associations between parent-reported HL on the one hand, and parent- and teacher-reported behavioural difficulties measured by the Strengths and Difficulties Questionnaire (SDQ) and parent-reported academic difficulties on the other hand, were investigated. RESULTS: After controlling for relevant confounding factors, significant associations were observed between parent-reported HL and parent- and teacher-reported Externalising scores, and academic difficulties. CONCLUSIONS: Childhood HL is associated with behavioural and academic difficulties. Parent reported HL in a non-clinical cohort is indicative for academic and behavioural difficulties.

Effects of oily fish intake on cardiovascular risk markers, cognitive function, and behavior in school-aged children: study protocol for a randomized controlled trial.

BACKGROUND: Most children in Western populations do not meet recommendations for fish consumption. Oily fish is an important source of n-3 long-chain polyunsaturated fatty acids (LCPUFA), which reduce blood pressure and plasma triacylglycerol in adults and may affect cognitive development and behavior. However, to our knowledge, the potential effects of oily fish on cardiometabolic health, cognitive function, and behavior in children have not been investigated. The aim of the FiSK Junior study is to investigate the effects of oily fish consumption on cardiovascular risk markers, cognitive function, and behavior in healthy children. METHODS/DESIGN: We are conducting a randomized controlled trial with 8- to 9-year-old Danish children, comparing the effect of consuming 300 g/week of oily fish with poultry (control) for 12 weeks between August 2016 and June 2017. The primary outcomes are blood pressure and fasting plasma triacylglycerol, which will be measured at baseline and endpoint. In addition, we will assess erythrocyte fatty acid composition (compliance), heart rate, plasma cholesterol, markers of glucose homeostasis, growth and body composition, dietary intake, and physical activity and sleep. We will also examine effects on cognitive function (attention, memory, and executive functions) by using standardized tests, behavior and emotions by administering parent-rated questionnaires and child interviews, and we will measure physiological stress response and cortisol levels. We need 150 children to complete the trial to detect a between-groups difference of 2.7 mmHg in diastolic blood pressure and 0.13 mmol/L in plasma triacylglycerol; thus, we aim to recruit 200 children. All outcomes will be analyzed in completer analysis supplemented with sensitivity analyses for the primary outcomes, and attention will be given to potential sex and genotype specificity. DISCUSSION: The results of the FiSK Junior study are expected to fill important gaps in the current knowledge about the importance of dietary fish and n-3 LCPUFA for children's health and development, and may be used when setting dietary recommendations. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02809508 . Registered on 22 June 2016.