Modellert påvirkning av lakselus på vill laksefisk

For å estimere påvirkningen lakselus fra oppdrett har på vill laksefisk langs hele norskekysten er det utviklet en rekke modellprodukt. Modellproduktene presentert i denne rapporten er ment å bli vurdert sammen med observasjoner, og gir tilleggsinformasjon ettersom modellproduktene spenner over større område, og over lengre tid enn det er mulig å observere alene. Rapporten omfatter hovedsaklig resultat for 2022. Modellproduktene inngår i Havforskningens bidrag til ekspertgruppen for trafikklyssystemet og grunnlaget for vurderingen av lakselus-indusert dødelighet per produksjonsområde.Modellert påvirkning av lakselus på vill laksefiskpublishedVersio

Overweight, obesity, and thinness among a nationally representative sample of Norwegian adolescents and changes from childhood: Associations with sex, region, and population density

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Modelled salmon lice dispersion and infestation patterns in a sub-arctic fjord

Salmon lice infestation is a major challenge for the aquaculture industry in Norway, threatening wild salmonid populations and causing welfare problems for farmed salmon. Lice dispersion and infestation patterns are simulated by combining a high-resolution hydrodynamic model for the Norwegian coast and fjords with an individual-based model for salmon lice. We here present results from Altafjorden, a sub-arctic fjord with large stocks of wild salmonids, where the inner part is protected as a National Salmon Fjord. The outer part of the fjord hosts several fish farms, and our simulations demonstrate how ocean currents can disperse lice between farms as well as into the protected part of the fjord. The relative contributions from the farms in the different parts of the fjord depends on their locations relative to the currents and circulation patterns in the fjord. Knowledge of how the highly variable water currents disperse salmon lice within fjord systems is necessary for managing farm locations and production quotas, if the goal is to minimize infestation pressure on wild salmonids and between fish farms.publishedVersio

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and associations with attention-deficit/hyperactivity disorder and autism spectrum disorder in children

Background Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) may be a risk factor for neurodevelopmental deficits and disorders, but evidence is inconsistent. Objectives We investigated whether prenatal exposure to PFAS were associated with childhood diagnosis of attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorder (ASD). Methods This study was based on the Norwegian Mother, Father and Child Cohort Study and included n = 821 ADHD cases, n = 400 ASD cases and n = 980 controls. Diagnostic cases were identified by linkage with the Norwegian Patient Registry. In addition, we used data from the Medical Birth Registry of Norway. The study included the following PFAS measured in maternal plasma sampled mid-pregnancy: Perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorohexane sulfonate (PFHxS), perfluoroheptanesulfonic acid (PFHpS), and perfluorooctane sulfonate (PFOS). Relationships between individual PFAS and ADHD or ASD diagnoses were examined using multivariable adjusted logistic regression models. We also tested for possible non-linear exposure-outcome associations. Further, we investigated the PFAS mixture associations with ASD and ADHD diagnoses using a quantile-based g-computation approach. Results Odds of ASD was significantly elevated in PFOA quartile 2 [OR = 1.71 (95% CI: 1.20, 2.45)] compared to quartile 1, and PFOA appeared to have a non-linear, inverted U-shaped dose-response relationship with ASD. PFOA was also associated with increased odds of ADHD, mainly in quartile 2 [OR = 1.54 (95% CI: 1.16, 2.04)] compared to quartile 1, and displayed a non-linear relationship in the restricted cubic spline model. Several PFAS (PFUnDA, PFDA, and PFOS) were inversely associated with odds of ADHD and/or ASD. Some of the associations were modified by child sex and maternal education. The overall PFAS mixture was inversely associated with ASD [OR = 0.76 (95% CI: 0.64, 0.90)] as well as the carboxylate mixture [OR = 0.79 (95% CI: 0.68, 0.93)] and the sulfonate mixture [OR = 0.84 (95% CI: 0.73, 0.96)]. Conclusion Prenatal exposure to PFOA was associated with increased risk of ASD and ADHD in children. For some PFAS, as well as their mixtures, there were inverse associations with ASD and/or ADHD. However, the inverse associations reported herein should not be interpreted as protective effects, but rather that there could be some unresolved confounding for these relationships. The epidemiologic literature linking PFAS exposures with neurodevelopmental outcomes is still inconclusive, suggesting the need for more research to elucidate the neurotoxicological potential of PFAS during early development

Association between gestational levels of toxic metals and essential elements and cerebral palsy in children

Introduction Cerebral palsy (CP) is the most common motor disability in childhood, but its causes are only partly known. Early-life exposure to toxic metals and inadequate or excess amounts of essential elements can adversely affect brain and nervous system development. However, little is still known about these as perinatal risk factors for CP. This study aims to investigate the associations between second trimester maternal blood levels of toxic metals, essential elements, and mixtures thereof, with CP diagnoses in children. Methods In a large, population-based prospective birth cohort (The Norwegian Mother, Father, and Child Cohort Study), children with CP diagnoses were identified through The Norwegian Patient Registry and Cerebral Palsy Registry of Norway. One hundred forty-four children with CP and 1,082 controls were included. The relationship between maternal blood concentrations of five toxic metals and six essential elements and CP diagnoses were investigated using mixture approaches: elastic net with stability selection to identify important metals/elements in the mixture in relation to CP; then logistic regressions of the selected metals/elements to estimate odds ratio (OR) of CP and two-way interactions among metals/elements and with child sex and maternal education. Finally, the joint effects of the mixtures on CP diagnoses were estimated using quantile-based g-computation analyses. Results The essential elements manganese and copper, as well as the toxic metal Hg, were the most important in relation to CP. Elevated maternal levels of copper (OR = 1.40) and manganese (OR = 1.20) were associated with increased risk of CP, while Hg levels were, counterintuitively, inversely related to CP. Metal/element interactions that were associated with CP were observed, and that sex and maternal education influenced the relationships between metals/elements and CP. In the joint mixture approach no significant association between the mixture of metals/elements and CP (OR = 1.00, 95% CI = [0.67, 1.50]) was identified. Conclusion Using mixture approaches, elevated levels of copper and manganese measured in maternal blood during the second trimester could be related to increased risk of CP in children. The inverse associations between maternal Hg and CP could reflect Hg as a marker of maternal fish intake and thus nutrients beneficial for foetal brain development

Association between gestational levels of toxic metals and essential elements and cerebral palsy in children

IntroductionCerebral palsy (CP) is the most common motor disability in childhood, but its causes are only partly known. Early-life exposure to toxic metals and inadequate or excess amounts of essential elements can adversely affect brain and nervous system development. However, little is still known about these as perinatal risk factors for CP. This study aims to investigate the associations between second trimester maternal blood levels of toxic metals, essential elements, and mixtures thereof, with CP diagnoses in children.MethodsIn a large, population-based prospective birth cohort (The Norwegian Mother, Father, and Child Cohort Study), children with CP diagnoses were identified through The Norwegian Patient Registry and Cerebral Palsy Registry of Norway. One hundred forty-four children with CP and 1,082 controls were included. The relationship between maternal blood concentrations of five toxic metals and six essential elements and CP diagnoses were investigated using mixture approaches: elastic net with stability selection to identify important metals/elements in the mixture in relation to CP; then logistic regressions of the selected metals/elements to estimate odds ratio (OR) of CP and two-way interactions among metals/elements and with child sex and maternal education. Finally, the joint effects of the mixtures on CP diagnoses were estimated using quantile-based g-computation analyses.ResultsThe essential elements manganese and copper, as well as the toxic metal Hg, were the most important in relation to CP. Elevated maternal levels of copper (OR = 1.40) and manganese (OR = 1.20) were associated with increased risk of CP, while Hg levels were, counterintuitively, inversely related to CP. Metal/element interactions that were associated with CP were observed, and that sex and maternal education influenced the relationships between metals/elements and CP. In the joint mixture approach no significant association between the mixture of metals/elements and CP (OR = 1.00, 95% CI = [0.67, 1.50]) was identified.ConclusionUsing mixture approaches, elevated levels of copper and manganese measured in maternal blood during the second trimester could be related to increased risk of CP in children. The inverse associations between maternal Hg and CP could reflect Hg as a marker of maternal fish intake and thus nutrients beneficial for foetal brain development

Prenatal Exposure to Acetaminophen and Risk of ADHD

OBJECTIVES: To estimate the association between maternal use of acetaminophen during pregnancy and of paternal use before pregnancy with attention-deficit/hyperactivity disorder (ADHD) in offspring while adjusting for familial risk for ADHD and indications of acetaminophen use. METHODS: Diagnoses were obtained from the Norwegian Patient Registry for 112 973 offspring from the Norwegian Mother and Child Cohort Study, including 2246 with ADHD. We estimated hazard ratios (HRs) for an ADHD diagnosis by using Cox proportional hazard models. RESULTS: After adjusting for maternal use of acetaminophen before pregnancy, familial risk for ADHD, and indications of acetaminophen use, we observed a modest association between any prenatal maternal use of acetaminophen in 1 (HR = 1.07; 95% confidence interval [CI] 0.96–1.19), 2 (HR = 1.22; 95% CI 1.07–1.38), and 3 trimesters (HR = 1.27; 95% CI 0.99–1.63). The HR for more than 29 days of maternal acetaminophen use was 2.20 (95% CI 1.50–3.24). Use for &amp;lt;8 days was negatively associated with ADHD (HR = 0.90; 95% CI 0.81–1.00). Acetaminophen use for fever and infections for 22 to 28 days was associated with ADHD (HR = 6.15; 95% CI 1.71–22.05). Paternal and maternal use of acetaminophen were similarly associated with ADHD. CONCLUSIONS: Short-term maternal use of acetaminophen during pregnancy was negatively associated with ADHD in offspring. Long-term maternal use of acetaminophen during pregnancy was substantially associated with ADHD even after adjusting for indications of use, familial risk of ADHD, and other potential confounders. </jats:sec

Educational achievement among children with a disability: do parental resources compensate for disadvantage?

We examined the impact of child disability on Grade Points Average (GPA) using all children aged 15–16 years who completed their lower secondary education and registered with a GPA score in the period from 2016 to 2020 in Norway (n = 247 120). We use registry data that contain information on the child's main diagnosis, such as physical-, neurological- and neurodevelopmental conditions, and the severity of the condition, additional to the child's family characteristics. First, we examined whether the impact of the child's disability on the GPA scores varied by diagnosis and the severity of the child's condition. Second, we examined whether higher parental socioeconomic status (SES) buffers against the negative impact of child disability on GPA scores. Using longitudinal register data with the school fixed-effect model, the results showed that children with neurological and neurodevelopmental disabilities obtained lower GPA scores than their typically developing peers without chronic conditions, however children with asthma and diabetes had comparable GPA scores. These associations were most evident for neurodevelopmental conditions, such as ADHD and autism but also notable for neurological conditions such as epilepsy. In general, a severe condition impacts GPA scores more negatively than a less severe condition. Moreover, our analysis revealed that children of highly educated parents obtained higher GPA scores than children who had parents with short education. This applied to both disabled and typically developing peers, except children with autism and epilepsy, among whom buffering due to the parent's education did not seem to apply

Essays on inequality and intergenerational mobility

En aquesta tesi s'analitza com les desigualtats econòmiques sorgeixen i persisteixen. La desigualtat ha augmentat en el món desenvolupat durant les últimes dècades. La tesi no només es centra en la desigualtat de resultats ja que estudia, sobretot, la desigualtat d'oportunitats. Una gran part de la desigualtat d'ingressos és conseqüència de la desigualtat en resultats educatius. Per tant, és important entendre en quines etapes educatives s'eixamplen les diferències i si l'accés a l'educació és diferent per als diversos segments de la població. També és essencial preguntar-se si l'educació per si sola pot igualar la societat o si la discriminació pot ser també un factor explicatiu important. En el primer capítol, investigo per què els països amb una desigualtat d'ingressos alta tenen una baixa mobilitat social entre generacions. Estudio aquesta relació en un model dinàstic de generacions solapades en què els pares poden invertir en l'educació escolar i universitària dels fills. Un augment en la prima de la universitat es tradueix en un augment dels incentius per invertir en l'educació primària i secundària a causa de les complementarietats dinàmiques entre l'educació inicial i superior. L'educació pública podria mitigar la relació entre la desigualtat i la mobilitat intergeneracional. No obstant, la despesa pública en educació es correlaciona negativament amb la desigualtat. Puc replicar aquesta relació endogeneïzant polítiques d'educació a través de la votació probabilística, considerant que la participació electoral està esbiaixada cap a la gent amb més educació. El model es calibra als Estats Units (EUA) com a economia de referència, la qual presenta una alta desigualtat i baixa mobilitat. Els experiments que comparen els EUA amb altres països de l'OCDE demostren que les característiques de l'educació terciària poden explicar dos terços de les diferències en desigualtat. Els patrons de participació electoral entre països expliquen gairebé una quarta part de les diferències en desigualtat i mobilitat. Un exercici contrafactual dels EUA suggereix que el vot obligatori podria fomentar la mobilitat intergeneracional. En el segon capítol, investigo per què la mobilitat d'ingressos intergeneracional és menor en els països on les dones tenen menys probabilitats de treballar i la despesa en educació preescolar pública és més baixa. Si menys dones treballen, llavors més mares són a casa amb els seus fills proporcionant un canal directe de transmissió d'habilitats. Faig servir un model dinàstic de generacions solapades que està calibrat als EUA. Les diferències en les despeses preescolars públiques de mitjana expliquen el 17% de les diferències en mobilitat intergeneracional entre els EUA i 15 països de l'OCDE i expliquen el 22% de la variació. En el tercer capítol, conjuntament amb Rajesh Ramachandran, es presenta un model en què la memòria col·lectiva de la discriminació del passat pot causar fallades de coordinació. Aquest tipus de discriminació pot sorgir per a les activitats que requereixen la participació de més d'un individu per al procés de producció. El model mostra com pot persistir la discriminació per sempre, fins i tot quan la capacitat dels individus és perfectament observable, el gust per la discriminació ha desaparegut així com l'absència de normes socials discriminatòries. Les persones sense una preferència per la discriminació, discriminen racionalment en equilibri impulsades per la creença sobre les accions discriminatòries per part dels altres. El model prediu una participació més baixa i major cost d'establir vincles per al grup discriminat en equilibri. Empíricament, s'analitzen les diferències entre negres i blancs en termes d'autoocupació als EUA. Es demostra que els negres tenen menors taxes de participació i que les creences sobre la discriminació són un factor significatiu en l'explicació de les taxes d'autoocupació més baixes dels negres als EUA.In this thesis I study how inequalities emerge and persist. Inequality has risen within the developed world over the past decades. However, I do not only focus on the inequality of outcomes, but particularly on the inequality of opportunity. A large part of income inequalities is the consequence of unequal educational outcomes. Therefore, it is important to understand at which educational stages the gaps are widened and why access to education might differ for different segments of the population. Many ethnicities and social groups are characterized by persistently low socio-economic indicators compared to the rest of the population. Therefore, it is also essential to ask whether education alone can level the playing field or whether discrimination might be an important explanatory factor as well. In the first chapter, I investigate why high earnings inequality goes hand in hand with low intergenerational earnings mobility across developed countries. I study this relationship in a dynastic overlapping generations model, in which a parent can invest in the early education of his child and decides whether to send the child to college. An increase in the college premium translates into increased incentives to invest in early education because of assumed dynamic complementarities between early and tertiary education. Public education could mitigate the relationship between inequality and intergenerational mobility. However, public expenditure on education is negatively correlated with inequality. I replicate this cross-country relationship by endogenizing education policies via probabilistic voting, while accounting for biases in voter turnout towards the educated. The model is calibrated to the US as the benchmark economy, which exhibits high inequality and low mobility. Experiments comparing the US to other OECD countries demonstrate that tertiary education characteristics can account for two-thirds of the differences in inequality. Patterns of voter turnout across countries explain nearly one-quarter of the differences in inequality and mobility. A counterfactual exercise for the US suggests that compulsory voting could foster intergenerational mobility, whereas the effect on pre-tax inequality is comparably low. In the second chapter, I study why intergenerational earnings mobility is lower in countries where females are less likely to work and public preschool expenditures are lower. When fewer females are working more mothers are at home with their children providing a direct channel of transmission of abilities. In order to account for cross-country differences in earnings persistence through differences in public preschool expenditures, a dynastic overlapping generations model is calibrated to the US. I find that differences in public preschool expenditures on average account for 17% of the differences in earnings persistence between the US and 15 OECD countries and can explain 22% of the variation. In the third chapter, joint with Rajesh Ramachandran, we present a model where the collective memory of past discrimination can cause coordination failures leading to present discrimination. The presented type of discrimination can arise for activities characterized by interlinkages, which require the input of more than one individual for the production process to be carried out. The model shows how discrimination can persist forever under perfectly observable ability, when taste for discrimination has died out, individual ability is ex-ante and ex-post identical, and in the absence of discriminatory social norms. Agents without a preference for discrimination rationally discriminate in equilibrium driven by the belief about discriminatory actions by others. The model predicts lower participation rates and higher costs of establishing interlinkages for the discriminated group in equilibrium. Empirically, we analyze differences between blacks and whites in terms of self-employment in the US finding that blacks have lower participation rates and that beliefs about discrimination are a significant factor in explaining lower self-employment rates of blacks in the US