The aims of this study were to estimate the prevalence of Delayed Sleep Phase Syndrome (DSPS) in adolescence, and to examine the association to insomnia and school non-attendance.

Docosahexaenoic acid (DHA, 22:6, n-3) is a long-chain polyunsaturated fatty acid necessary for normal brain growth and cognitive development. Seafood and dietary supplements are the primary dietary sources of DHA. This study addresses the associations between DHA status in pregnant women and healthy, term-born infant problem-solving skills assessed using the Ages and Stages Questionnaire. The fatty acid status of maternal red blood cells (RBCs) was assessed in the 28th week of gestation and at three months postpartum. The infants’ fatty acid status (RBC) was assessed at three, six, and twelve months, and problem-solving skills were assessed at six and twelve months. Maternal DHA status in pregnancy was found to be positively associated with infants’ problem-solving skills at 12 months. This association remained significant even after controlling for the level of maternal education, a surrogate for socio-economic status. The infants’ DHA status at three months was associated with the infants’ problem solving at 12 months. The results accentuate the importance for pregnant and lactating women to have a satisfactory DHA status from dietary intake of seafood or other sources rich in DHA.

Assessment of adolescents’ dietary habits is challenging. Reliable instruments to monitor dietary trends are required to promote healthier behaviours in this group. The purpose of this cross-sectional study was to assess adolescents’ adherence to Norwegian dietary recommendations with a diet score and to report results from, and test-retest reliability of, the score. The diet score involved seven food groups and one physical activity indicator, and was applied to answers from a semi-quantitative food frequency questionnaire (FFQ) administered twice. Reproducibility of the score was assessed with Cohen’s Kappa (κ statistics) at an interval of three months. The setting was eight lower-secondary schools in Hordaland County, Norway, and subjects were adolescents (n = 472) aged 14–15 years and their caregivers. Results showed that the proportion of adolescents consistently classified by the diet score was 87.6% (κ = 0.465). For food groups, proportions ranged from 74.0% to 91.6% (κ = 0.249 to κ = 0.573). Less than 40% of the participants were found to adhere to recommendations for frequencies of eating fruits, vegetables, added sugar, and fish. Highest compliance to recommendations was seen for choosing water as beverage and limit the intake of red meat. The score was associated with parental socioeconomic status. The diet score was found to be reproducible at an acceptable level. Health promoting work targeting adolescents should emphasize to increase the intake of recommended foods to approach nutritional guidelines.

Adolescence involves changes in dietary habits that may induce imbalances in the intake of different nutrients. Fish is an important dietary source of omega-3 (n-3) long-chain polyunsaturated fatty acids (LCPUFAs), vitamin D, several minerals and high-quality protein. By using secondary outcomes and exploratory analyses, the aims of this paper were to evaluate if nutritional biomarkers (red blood cell fatty acids, serum (s)-25(OH)D, s-ferritin and urinary iodine concentration (UIC)) were altered during a dietary intervention, and if they mediated previously reported changes in attention performance. In addition, to examine the status of the biomarkers and explore associations between dietary pattern, biomarkers and attention performance cross-sectionally at baseline. The Fish Intervention Studies-TEENS (FINS-TEENS) was a three-armed intervention trial, including adolescents from eight secondary schools (n = 415; age: 14–15y) in Bergen, Norway. Participants were individually randomized to receive either fish meals, meat meals or n-3 LCPUFA supplements, three times a week for a total of 12 weeks. Blood and urine samples were collected pre and post intervention and attention performance was assessed with the d2 test of attention. Analyses of covariance (ANCOVA) assessed differences between groups in changes of biomarkers and linear mixed models were applied in analyses of attention performance and biomarkers. The trial is registered in ClinicalTrials.gov (NCT02350322). At baseline, the mean omega-3 index was 5.8 ± 1.3% and deficient status were identified for s-25(OH)D (54%), s-ferritin (10%) and UIC (40%). The intervention resulted in an increase in DHA and the omega-3 index which was larger in the supplement group compared to the fish and meat group (P < 0.01), and in the fish group compared to the meat group (P < 0.01). No differences between the groups were observed for changes in 25(OH)D, s-ferritin or UIC. None of the biomarkers mediated performance in the d2 test. The intake of fatty fish and a healthy dietary pattern was associated with scores in processing speed at baseline. These results show that Norwegian adolescents have insufficient status of important nutrients, which may be improved with fatty fish consumption or n-3 LCPUFA supplements. However, nutritional status was not associated with scores in the d2 test of attention.

School absenteeism is linked to a range of health concerns, health risk behaviors and school dropout. It is therefore important to evaluate the extent to which adolescents with absenteeism are in contact with health care and other services. The aim of the current study was to investigate service use of Norwegian adolescents with moderate and high absenteeism in comparison to students with lower rates of absence. The study employs data from a population-based study from 2012 targeting all pupils in upper secondary education in Hordaland County, Norway (the youth@hordaland-survey). A total of 8988 adolescents between the ages of 16 and 18 were included in the present study. Information on service use was based on adolescent self-report data collected in the youth@hordaland-survey. Absence data was collected using administrative data provided by the Hordaland County Council. High absence (defined as being absent 15 % or more the past semester) was found among 10.1 % of the adolescents. Compared to their peers with low absence (less than 3 % absence the past semester), adolescents with high absence were more likely to be in contact with all the services studied, including mental health services (odds ratio (OR) 3.96), adolescent health clinics (OR 2.11) and their general practitioner (GP) (OR 1.94). Frequency of contact was higher among adolescents with moderate and high absence and there seems to be a gradient of service use corresponding to the level of absence. Still, 40 % of the adolescents with high absence had not been in contact with any services. Adolescents with high absence had increased use of services, although a group of youth at risk seems to be without such contact. This finding suggests a potential to address school absenteeism through systematic collaboration between schools and health personnel.

Fatty fish is the dominant dietary source of n-3 LCPUFAs but it also contains other micronutrients considered important for brain development and function. To our knowledge, the effect of fatty fish intake on cognitive function in adolescents has not been investigated in randomized controlled trials (RCTs) previously. The aim of the present trial was to investigate whether consumption of fatty fish meals three times per week for 12 weeks could alter attention performance in adolescents compared to similar meals with meat or n-3 LCPUFA supplements. In the Fish Intervention Studies-TEENS (FINS-TEENS), adolescents from eight secondary schools (n = 426; age: 14-15y) were individually randomized. Attention performance was assessed with the d2 test of attention. Differences between groups from pre to post intervention were assessed with linear mixed effect models and general estimates equation. The fish group was set as reference. Dietary compliance was recorded for each meal throughout the trial and controlled for in the adjusted analyses. The improvement in processing speed was significantly lower in the meat (−11.8; 95% CI: -23.3, −0.4) and supplement (−13.4; 95% CI: -24.9, −1.8) group compared to the fish group (reference). The supplement group also showed inferior improvement in total performance (−10.4; 95% CI: -20.0, −0.7) compared to the fish group (reference). The results were slightly affected when controlling for dietary compliance. Omission errors decreased in the meat group compared to the fish group (Incidence rate ratio = 0.85; 95% CI: 0.74, 0.98), but the difference disappeared when controlling for dietary compliance. We observed a small beneficial effect of fatty fish, compared to meat meals and supplements on processing speed. However, these results are difficult to interpret due to low dietary compliance. This study shows that different taste preferences among participants is challenging in intervention trials with food. A prospective cohort design may be a better alternative when studying diet in the future. ClinicalTrials.gov registration number: NCT02350322 .