Doctoral Defence in Biostatistics – Ingibjörg Magnúsdóttir

On Wednesday, 28 October, Ingibjörg Magnúsdóttir will defend her doctoral thesis in Biostatistics at the Faculty of Medicine, University of Iceland. The thesis is entitled: Mental, physical, and cognitive manifestations of post COVID-19 condition: Evidence from population-based cohorts and national registers.

The opponents are Dr Frode Forland, Director at the Norwegian Institute of Public Health (NIPH), and Dr Nisreen A Alwan, Professor at the University of Southampton.

The principal supervisor was Thor Aspelund, and the co-supervisor was Unnur Anna Valdimarsdóttir, Professor. Other members of the doctoral committee were Arna Hauksdóttir, Professor; Elías Sæbjörn Eyþórsson, Research Scientist; and Fang Fang, Professor.

Stefán Þ. Sigurðsson, Professor and Vise Dean of the Faculty of Medicine, will preside over the ceremony, which will take place in the Ceremonial Hall of the University of Iceland and begin at 9:00 a.m.

Abstract

The COVID-19 pandemic raised concerns about the long-term health consequences of infection, yet evidence from general population studies with extended follow-up has remained limited. The aim of this thesis was to investigate long-term mental, physical, and cognitive health outcomes following COVID-19 and to examine the role of acute illness severity in these outcomes.

The thesis comprises four studies based on cohort and population-wide health data from Iceland and other Nordic countries. Individuals diagnosed with COVID-19 were more likely to experience depressive symptoms, poor sleep quality, and persistent physical symptoms compared with those not diagnosed. They were also at increased risk of psychiatric disorders and psychotropic medication use following infection. In contrast, no overall association was observed between COVID-19 diagnosis and impaired cognitive function.

Across all studies, acute illness severity emerged as a key determinant of long-term outcomes. Individuals with severe illness, defined by being bedridden for seven days or longer, experienced substantially higher risks of persistent mental, physical, and cognitive symptoms that could last for more than two years after diagnosis. In contrast, individuals with mild illness showed little to no increased risk.

These findings improve understanding of post COVID-19 condition and highlight the importance of considering acute illness severity in research, clinical evaluation, and long-term follow-up after COVID-19.

About the doctoral candidate

Ingibjörg Magnúsdóttir was born in Reykjavík in 1989. She graduated from the Natural Sciences programme at Menntaskólinn við Hamrahlíð in 2009, completed a B.Sc. degree in Environmental and Civil Engineering at the University of Iceland in 2015, and an M.Sc. degree in Biostatistics from the same university in 2021. Ingibjörg began her doctoral studies at the University of Iceland in 2021.

Ingibjörg's parents are Ellý Katrín Guðmundsdóttir, a lawyer and former City Secretary of Reykjavík (died in 2024), and Magnús Karl Magnússon, a physician and professor. Ingibjörg's partner is Beatrice Eriksson, a social worker, and their son is Almar Elí.