Academic article

• Knut Asbjørn Alexander Øymar; Joel Pradeepkumar Selvakumar; Maren Våland Øymar et al. (2026). High-Flow Nasal Cannula and Continuous Positive Airway Pressure in Infants With Acute Bronchiolitis—Trends of Use in Norway. (external link)
• Karen Galta Sørensen; Knut Asbjørn Alexander Øymar; Ingvild Dalen et al. (2025). Bronchial hyper-reactivity in young adults after hospitalisation for bronchiolitis in infancy. (external link)
• Maren Våland Øymar; Joel Pradeepkumar Selvakumar; Ingvild Dalen et al. (2025). Regional Differences and Time Trends in the Treatment of Infants Hospitalised With Bronchiolitis in Norway. (external link)
• Jørgen Erland Linde; Jeffrey M. Perlman; Knut Øymar et al. (2018). Predictors of 24-h outcome in newborns in need of positive pressure ventilation at birth. (external link)
• Sofie Helen Vaula; Knut Asbjørn Alexander Øymar; Vegard Hovland et al. (2024). Trakeobronkomalasi hos barn. (external link)
• Knut Øymar; Lage Aksnes (2004). Urinary 9 alpha,11 beta-prostaglandin F-2 in children with atopic eczema/dermatitis syndrome: An indicator of mast cell activation?. (external link)
• Antje Aarthun; Knut Øymar; Kristin Akerjordet (2019). Parental involvement in decision-making about their child's health care at the hospital. (external link)
• Anne Lise Bjørke Monsen; Maria Vollsæter; Per Magne Ueland et al. (2016). Increased bronchial hyperresponsiveness and higher asymmetric dimethylarginine levels after fetal growth restriction. (external link)
• Bjørn Barstad; Dag Tveitnes; Ingvild Dalen et al. (2019). The B-lymphocyte chemokine CXCL13 in the cerebrospinal fluid of children with Lyme neuroborreliosis: associations with clinical and laboratory variables. (external link)
• Maria Vollsæter; Kaia Skromme; Emma Elsa Carolina Satrell et al. (2015). Children born preterm at the turn of the millennium had better lung function than children born similarly preterm in the early 1990s. (external link)
• Siren Rettedal; Iren Høyland Löhr; Olav Bjarte Natås et al. (2012). First outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a Norwegian neonatal intensive care unit; associated with contaminated breast milk and resolved by strict cohorting. (external link)
• Bjørn Barstad; Hanne Quarsten; Dag Tveitnes et al. (2018). Direct molecular detection and genotyping of borrelia burgdorferi sensu lato in cerebrospinal fluid of children with lyme neuroborreliosis. (external link)
• Ingvild Bruun Mikalsen; Thomas Halvorsen; Pétur Benedikt Juliusson et al. (2021). Early life growth and associations with lung function and bronchial hyperresponsiveness at 11-years of age. (external link)
• Peder Aleksander Bjorland; Knut Øymar; Hege Langli Ersdal et al. (2019). Incidence of newborn resuscitative interventions at birth and short-term outcomes: A regional population-based study. (external link)
• Peder Aleksander Bjorland; Hege Langli Ersdal; Joar Eilevstjønn et al. (2020). Changes in heart rate from 5 s to 5 min after birth in vaginally delivered term newborns with delayed cord clamping. (external link)
• Knut Øymar; Jakob Havnen; Thomas Halvorsen et al. (2001). Eosinophil counts and urinary eosinophil protein X in children hospitalized for wheezing during the first year of life: prediction of recurrent wheezing. (external link)
• Knut Øymar; Robert Bjerknes (2001). Urinary eosinophil protein X in children with asthma: influence of atopy and airway infections. (external link)
• Knut Øymar; Thomas Halvorsen; Lage Aksnes (2006). Mast cell activation and leukotriene secretion in wheezing infants. Relation to respiratory syncytial virus and outcome. (external link)
• Alan Martin Edwards; Dalia Bibawy; Sharon Matthews et al. (2015). Long-term use of a 4% sodium cromoglicate cutaneous emulsion in the treatment of moderate to severe atopic dermatitis in children. (external link)
• Karen Galta Sørensen; Knut Asbjørn Alexander Øymar; Ingvild Dalen et al. (2022). Asthma, atopy and lung function in young adults after hospitalisation for bronchiolitis in infancy: Impact of virus and sex. (external link)
• Bjørn Barstad; Anna J. Henningsson; Dag Tveitnes et al. (2020). Cerebrospinal fluid cytokines and chemokines in children with Lyme neuroborreliosis; pattern and diagnostic utility. (external link)
• Dag Tveitnes; Knut Øymar (2015). Gender differences in childhood lyme neuroborreliosis. (external link)
• Knut Øymar (2007). Allergivaksinasjon i Norge. (external link)
• Knut Øymar; Einar Klæboe Kristoffersen (2007). Periodisk feber-syndrom hos barn. (external link)
• Knut Øymar; Jakob Havnen; Thomas Halvorsen et al. (2001). Eosinophil counts and urinary eosinophil protein X in children hospitalize for wheezing during the first year of life: prediction of recurrent wheezing. (external link)
• Karen Galta Sørensen; Knut Øymar; Ingvild Dalen et al. (2019). Lung function and bronchial hyper-reactivity from 11 to 18 years in children with bronchiolitis in infancy. (external link)
• Ingvild Bruun Mikalsen; Thomas Halvorsen; Knut Øymar (2012). The outcome after severe bronchiolitis is related to gender and virus. (external link)
• Peder Aleksander Bjorland; Hege Langli Ersdal; Joanna Clare Haynes et al. (2021). Tidal volumes and pressures delivered by the NeoPuff T-piece resuscitator during resuscitation of term newborns. (external link)
• David Hugo Engelsvold; Knut Øymar (2003). Innleggelser for akutt astme hos barn. (external link)
• David Hugo Engelsvold; Knut Øymar (2003). Hospital admissions for childhood asthma in Rogaland, Norway from 1984 to 2000. (external link)
• B Ellingsen; S Ase; Knut Øymar (2003). Forebygging av respiratorisk syncytalvirus-infeksjoner med pailvizumlab. (external link)
• Mette Engan; Maria Vollsæter; Knut Øymar et al. (2019). Comparison of physical activity and body composition in a cohort of children born extremely preterm or with extremely low birth weight to matched term-born controls: a follow-up study. (external link)
• Anlaug Vatne; Claus Klingenberg; Siren Rettedal et al. (2021). Early-Onset Sepsis in Neonates - A Population-Based Study in South-West Norway From 1996 to 2018. (external link)
• Kristine Kjer Byberg; Geir Egil Eide; Michele R. Forman et al. (2016). Body mass index and physical activity in early childhood are associated with atopic sensitization, atopic dermatitis and asthma in later childhood. (external link)
• Kristine Kjer Byberg; Ingvild Bruun Mikalsen; Geir Egil Eide et al. (2018). The associations between weight-related anthropometrics during childhood and lung function in late childhood: A retrospective cohort study. (external link)
• Ingvild Bruun Mikalsen; Thomas Halvorsen; Geir Egil Eide et al. (2013). Severe bronchiolitis in infancy: Can asthma in adolescence be predicted?. (external link)
• Alet Jenny Røsvik; Knut Øymar; Jan Terje Kvaløy et al. (2009). Oxygen saturation in healthy newborns; influence of birth weight and mode of delivery. (external link)
• Ingvild Bruun Mikalsen; Thomas Halvorsen; Knut Øymar (2013). Exhaled nitric oxide is related to atopy, but not asthma in adolescents with bronchiolitis in infancy. (external link)
• Dag Tveitnes; Knut Øymar; Olav B. Natås (2009). Laboratory data in children with Lyme neuroborreliosis, relation to clinical presentation and duration of symptoms. (external link)
• Trine Haug Popperud; Marion Boldingh; Cathrine Brunborg et al. (2017). Juvenile myasthenia gravis in Norway: A nationwide epidemiological study. (external link)
• Ingvild Bruun Mikalsen; Thomas Halvorsen; Knut Øymar (2014). Blood eosinophil counts during bronchiolitis are related to bronchial hyper-responsiveness and lung function in early adolescence. (external link)
• Kristine Byberg; Knut Øymar; Lage Aksnes (2008). Fatty acids in cord blood plasma, the relation to soluble CD23 and subsequent atopy. (external link)
• Inge Hagen; Knut Øymar (2009). Pharmacological differences between once daily and twice daily gentamicin dosage in newborns with suspected sepsis. (external link)
• Mariann Bentsen; Trond Markestad; Knut Øymar et al. (2017). Lung function at term in extremely preterm-born infants: A regional prospective cohort study. (external link)
• Knut Øymar; Ingvild Bruun Mikalsen; Suzanne Crowley (2017). Protrahert bakteriell bronkitt hos barn. (external link)
• Jostein Andersen Førsvoll; Einar Klæboe Kristoffersen; Knut Øymar (2013). Elevated levels of CXCL10 in the Periodic Fever, Aphthous stomatitis, Pharyngitis and cervical Adenitis syndrome (PFAPA) during and between febrile episodes; an indication of a persistent activation of the innate immune system. (external link)
• Antje Aarthun; Knut Øymar; Kristin Akerjordet (2019). Health professionals’ involvement of parents in decision-making in interprofessional practice at the hospital. (external link)
• Knut Øymar; Åge Lærdal; Robert Bjerknes (2000). Soluble CD30 and CD23 in cord blood are not related to atopy in early childhood. (external link)
• Knut Øymar; Dag Tveitnes (2009). Clinical characteristics of childhood Lyme neuroborreliosis in an endemic area of northern Europe. (external link)
• Kaia Skromme; Maria Vollsæter; Knut Øymar et al. (2018). Respiratory morbidity through the first decade of life in a national cohort of children born extremely preterm. (external link)
• Atle Røsvik; Knut Øymar; Jan Terje Kvaløy et al. (2009). Oxygen saturation in healthy newborns; influence of birth weight and mode of delivery. (external link)
• Knut Øymar; Robert Bjerknes (2000). Urinary eosinophil protein X in children with atopic dermatitis: relation to atopy and disease activity. (external link)
• Mette Engan; Merete Salveson Engeset; Lorentz Sandvik et al. (2022). Left vocal cord paralysis, lung function and exercise capacity in young adults born extremely preterm with a history of neonatal patent ductus arteriosus surgery—A national cohort study. (external link)
• Jostein A. Førsvoll; Knut Øymar (2007). C-reactive protein in the periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome. (external link)
• Knut Øymar; Lage Aksnes (2005). Increased levels of urinary leukotriene E4 in children with severe atopic eczema/dermatitis syndrome. (external link)
• Dag Tveitnes; Olav Bjarte Natås; Øyvind Skadberg et al. (2012). Lyme meningitis, the major cause of childhood meningitis in an endemic area: a population based study. (external link)
• Kristine Kjer Byberg; Knut Øymar; Geir Egil Eide et al. (2017). Exposure to preeclampsia in utero affects growth from birth to late childhood dependent on child's sex and severity of exposure: Follow-up of a nested case-control study. (external link)
• Anlaug Vatne; Claus Klingenberg; Knut Øymar et al. (2020). Reduced antibiotic exposure by serial physical examinations in term neonates at risk of early-onset sepsis. (external link)
• Maria Vollsæter; Thomas Halvorsen; Trond Markestad et al. (2018). Renal function and blood pressure in 11 year old children born extremely preterm or small for gestational age. (external link)
• Knut Øymar; Gjermund Fluge; Karen Rosendahl (1993). Residiverende abdominalsmerter. En prospektiv undersøkelse. (external link)
• Thomas Halvorsen; Brit Skadberg; Geir Egil Eide et al. (2005). Characteristics of asthma and airway hyper-responsiveness after premature birth. (external link)
• Jostein Andersen Førsvoll; Knut Øymar (2018). The role of tonsillectomy in the Periodic Fever, Aphthous stomatitis, Pharyngitis and cervical Adenitis syndrome; A literature review. (external link)
• M. Aurivillius; Knut Øymar; V-A Oxelius (2005). Immunoglobulin heavy G2 chain (IGHG2) gene restriction in the development of severe respiratory syncytial virus infection. (external link)
• Knut Øymar; Lage Aksnes (2005). Increased levels of urinary leukotriene E4 in children with severe eczema/dermatitis syndrome. (external link)
• Ingvild Bruun Mikalsen; Liliane Merete Skeiseid; Line Merete Tveit et al. (2015). Decline in admissions for childhood asthma, a 26-year period population-based study. (external link)
• Knut Øymar; Atle Røsvik; Jan Fossheim et al. (2007). Regelmessige episoder med høy feber hos en liten gutt. (external link)
• Knut Øymar; Robert Bjerknes (1998). Differential patterns of circulating adhesion molecules in children with bronchial asthma, and acute bronchiolitis. (external link)
• Zuzana Huncikova; Anlaug Vatne; Hans Jørgen Stensvold et al. (2023). Late-onset sepsis in very preterm infants in Norway in 2009-2018: A population-based study. (external link)
• Jostein Andersen Førsvoll; Emilius Adrianus Maria Janssen; Ingegerd Møller et al. (2015). Reduced number of CD8+ cells in tonsillar germinal centres in children with the periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis syndrome. (external link)
• Knut Øymar; Said Elsayed; Robert Bjerknes (1997). Serum eosinophil cationic protein and interleukin-5 in childeren with bronchial asthma and acute bronchiolitis. (external link)
• Knut Øymar; Robert Bjerknes (1998). Is serum eosinophil cationic protein in bronchiolitis a predictor of asthma?. (external link)
• Karen Galta Sørensen; Ingvild Bruun Mikalsen; Axel Cornelis Neven et al. (2020). Half of children with recurrent or chronic wet cough before three years of age were symptom-free by age seven. (external link)
• Peder Aleksander Bjorland; Hege Langli Ersdal; Knut Øymar et al. (2020). Compliance with Guidelines and Efficacy of Heart Rate Monitoring during Newborn Resuscitation: A Prospective Video Study. (external link)
• Iren Høyland Löhr; Siren Rettedal; Olav Bjarte Natås et al. (2013). Long-term faecal carriage in infants and intra-household transmission of CTX-M-15-producing Klebsiella pneumoniae following a nosocomial outbreak. (external link)
• Dag Tveitnes; Knut Øymar; Olav B. Natås (2007). Acute facial nerve palsy in children: How often is it Lyme borreliosis?. (external link)
• Kristine Kjer Byberg; Bjørn Edvin Øglænd; Geir Egil Eide et al. (2014). Birth after preeclamptic pregnancies: Association with allergic sensitization and allergic rhinoconjunctivitis in late childhood; a historically matched cohort study. (external link)
• Jostein Andersen Førsvoll; Einar Klæboe Kristoffersen; Knut Øymar (2013). Incidence, clinical characteristics and outcome in Norwegian children with periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis syndrome; a population-based study. (external link)
• Ingvild Bruun Mikalsen; Damoun Nassehi; Knut Øymar (2018). Vortex whistle and smart phone application for peak flow recordings in asthmatic children: A feasibility study. (external link)
• Zuzana Huncikova; Hans Jørgen Stensvold; Knut Asbjørn Alexander Øymar et al. (2023). Variation in antibiotic consumption in very preterm infants-a 10 year population-based study. (external link)
• Jørgen Erland Linde; Jörn Schulz; Jeffrey M. Perlman et al. (2016). Normal newborn heart rate in the first five minutes of life assessed by dry-electrode electrocardiography. (external link)
• Siren Rettedal; Iren Høyland Löhr; Olav Bjarte Natås et al. (2013). Risk factors for acquisition of CTX-M-15 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae during an outbreak in a neonatal intensive care unit in Norway. (external link)
• Ingvild Bruun Mikalsen; Ingvild Dalen; Øystein Karlstad et al. (2019). Airway symptoms and atopy in young children prescribed asthma medications: A large‐scale cohort study. (external link)
• Tonje Bårdsen; Emma Satrell; Ola Drange Røksund et al. (2024). Lung function outcomes in adults born extremely preterm across three decades of advancing perinatal medicine. (external link)
• Ann Marit Gilje; Per Kristian Knudsen; Knut Øymar (2011). Ei ung jente med magesmerter. (external link)
• Jørgen Erland Linde; Jörn Schulz; Jeffrey M. Perlman et al. (2017). The relation between given volume and heart rate during newborn resuscitation. (external link)
• Karen Galta Sørensen; Knut Asbjørn Alexander Øymar; Ingvild Dalen et al. (2023). Blood eosinophils during bronchiolitis: Associations with atopy, asthma and lung function in young adults. (external link)
• Knut Øymar; Ingvild Bruun Mikalsen; Kari Furu et al. (2015). Prescription patterns of inhaled corticosteroids for preschool children - A Norwegian register study. (external link)
• Amélie E. Bigorgne; Henner F. Farin; Roxane Lemoine et al. (2014). TTC7A mutations disrupt intestinal epithelial apicobasal polarity. (external link)
• Ingvild Bruun Mikalsen; Øystein Karlstad; Kari Furu et al. (2018). Forskrivning av legemidler mot astma til barn i perioden 2004–15. (external link)
• Knut Øymar; Dag Tveitnes (2008). Økt forekomst av nevroborreliose hos barn. (external link)
• Antje Aarthun; Knut Øymar; Kristin Akerjordet (2017). How health professionals facilitate parents' involvement in decision-making at the hospital: A parental perspective. (external link)
• Jørgen Erland Linde; Joar Eilevstjønn; Knut Øymar et al. (2017). Feasibility of a prototype newborn resuscitation monitor to study transition at birth, measuring heart rate and ventilator parameters, an animal experimental study. (external link)
• Tonje Bårdsen; Ola Drange Røksund; Merete Benestad et al. (2022). Tracking of lung function from 10 to 35 years after being born extremely preterm or with extremely low birth weight. (external link)
• Lise Reindal; Knut Øymar (2006). Hospital admissions for wheezing and asthma in childhood - are they avoidable?. (external link)
• Ingvild Bruun Mikalsen; Kristine Kjer Byberg; Michele R. Forman et al. (2020). Adipokines in adolescence; the associations with lung function and atopy – A cross-sectional study. (external link)
• Bjørn Barstad; Dag Tveitnes; Sølvi Noraas et al. (2017). Cerebrospinal Fluid B-lymphocyte Chemoattractant CXCL13 in the Diagnosis of Acute Lyme Neuroborreliosis in Children. (external link)
• Knut Øymar; Kjersti Bårdsen (2014). Continuous positive airway pressure for bronchiolitis in a general paediatric ward; a feasibility study. (external link)
• Siren Rettedal; Iren Høyland Löhr; Eva Bernhoff et al. (2015). Extended-spectrum β-lactamase-producing Enterobacteriaceae among pregnant women in Norway: Prevalence and maternal-neonatal transmission. (external link)
• Karen Galta Sørensen; Knut Asbjørn Alexander Øymar; Grete Jonsson et al. (2023). Are BMI and adipokines associated with asthma, atopy and lung function in young adults previously hospitalized for bronchiolitis?. (external link)
• Emilie Raaum Closs; Miriam Lyamouri; Knut Asbjørn Alexander Øymar et al. (2023). Regionale forskjeller i bruk av protonpumpehemmere hos barn. (external link)

Study protocol

• Trude Elvebakk; Henrik Døllner; Anna Partty et al. (2025). INnovative Steroid Treatment to reduce Asthma development in children after first-time Rhinovirus-induced wheezing (INSTAR): protocol for a randomised placebo-controlled trial. (external link)

Media feature article

• Knut Asbjørn Alexander Øymar; Erling Tjora; Ketil Størdal (2025). Ammende trenger sjelden å slutte med kumelk. (external link)
• Knut Øymar (2012). Bruk av inhalasjonssteroider hos førskolebarn. (external link)

Academic literature review

• Ingvild Bruun Mikalsen; Peter Davis; Knut Øymar (2016). High flow nasal cannula in children: A literature review. (external link)
• Jostein Andersen Førsvoll; Einar Klæboe Kristoffersen; Knut Øymar (2019). The immunology of the periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis syndrome; what can the tonsils reveal. A literature review.. (external link)
• Knut Øymar (2000). Bakteriell trakeitt hos barn. (external link)
• Knut Øymar (1997). Diskitt hos barn. Beskrivelse av tilstanden illustrert ved to eksempler. (external link)
• Knut Øymar; Håvard Ove Skjerven; Ingvild Bruun Mikalsen (2014). Acute bronchiolitis in infants, a review. (external link)
• Knut Øymar; Thomas Halvorsen (2009). Emergency presentation and management of acute severe asthma in children. (external link)

Letter to the editor

• Knut Øymar; Ingvild Bruun Mikalsen; Suzanne Crowley (2018). K. Øymar og medarbeidere svarer. (external link)
• Karen Galta Sørensen; Knut Asbjørn Alexander Øymar; Thomas Halvorsen et al. (2023). Blood eosinophils during bronchiolitis were not associated with adult asthma in a Norwegian cohort study. (external link)
• Knut Øymar; Ingvild Bruun Mikalsen; Torbjørn Nag et al. (2017). Systemiske steroider til førskolebarn med symptomer fra nedre luftveier. (external link)
• Ingvild Bruun Mikalsen; Thomas Halvorsen; Knut Øymar (2013). The optimal management for patients (Letter). (external link)
• Dag Tveitnes; Reidar Hjetland; Knut Øymar (2013). Tolking av serologiske testar. (external link)
• Knut Asbjørn Alexander Øymar; Øystein Karlstad; Ketil Størdal (2021). Har anbefalinger om endring av behandling effekt?. (external link)
• Karen Galta Sørensen; Knut Asbjørn Alexander Øymar; Thomas Halvorsen et al. (2020). Reply to Korppi and Riikonen. (external link)
• Christine Louise Parr; Wenche Nystad; Øystein Karlstad et al. (2022). Ten-year trends of national healthcare costs of asthma, allergic rhinitis, and atopic eczema in 3 million Norwegians. (external link)

Doctoral thesis (PhD)

• Siren Irene Rettedal; Knut Øymar (2016). Extended-spectrum beta-lactamase producing Enterobacteriaceae in neonates; Hospital outbreak, colonization, transmission and persistence. (external link)
• Knut Øymar (2001). Eosinophil inflammation in children with asthma, wheezing and atopic dermatitis. (external link)
• Kristine Kjer Byberg; Bjørn Edvin Øglænd; Knut Øymar (2017). An epidemiological study on the associations between preeclampsia exposure, growth and physical activity in preschool age and subsequent allergy, asthma and lung function in late childhood. (external link)
• Mariann Bentsen; Thomas Halvorsen; Trond Markestad et al. (2018). Tidal breathing parameters in extremely premature infants. Feasibility and clinical utility of electromagnetic inductance plethysmography. (external link)
• Jostein Andersen Førsvoll; Knut Øymar (2015). The Periodic Fever, Aphthous stomatitis, Pharyngitis and cervical Adenitis syndrome in children. Clinical and immunological aspects. (external link)

Conference poster

• Maria Vollsæter; Hege Synnøve Havstad Clemm; Einar Thorsen et al. (2014). Alveolar nitric oxide(NO)in children born extremely preterm (EP).. (external link)
• Merete Salveson Engeseth; Hege Synnøve Havstad Clemm; Ola Drange Røksund et al. (2015). Better respiratory outcomes for extremely preterm born children.. (external link)

Conference lecture

• Knut Øymar (2005). Palivizumab ved lungesykdommer, contra. (external link)
• Knut Øymar (2005). Allergivaksinering, status i Norge. (external link)
• Knut Øymar (2005). Periodisk febersyndrom hos barn. (external link)

See a complete overview of publications in NVA.