Thor Aspelund

University of Iceland | HI · Epidemiology and Biostatistics Department of Medicine

Emerging data suggest that certain adverse childhood experiences (ACEs) are associated with perinatal depression (PND). However, few studies have comprehensively assessed the cumulative number and types of ACEs and their association to PND. We conducted a cross-sectional analysis among 16,831 female participants from the Stress-And-Gene-Analysis (S...

Childhood maltreatment has been associated with some infection-related outcomes, yet its potential role in severe COVID-19 outcomes has not been addressed. Therefore, leveraging longitudinal data from the population-based UK Biobank (N=151,427), our study aimed to explore the association between childhood maltreatment and severe COVID-19 outcomes (...

Background. Little is known regarding the mental health impact of having a significant person (family member and/or close friend) with COVID-19 of different severity. Methods. The study included five prospective cohorts from four countries (Iceland, Norway, Sweden, and the UK) with self-reported data on COVID-19 and symptoms of depression and anxie...

Aim To study the effect of positive airway pressure (PAP) treatment on nocturnal gastroesophageal reflux (nGER) and respiratory symptoms among clinical OSA patients. Methods 822 newly diagnosed patients with OSA referred for PAP treatment were recruited. 732 subjects had a 2-year follow-up visit with CPAP compliance data collected (366 full PAP us...

A decline in forced expiratory volume (FEV1) is a hallmark of obstructive respiratory diseases, an important cause of morbidity among the elderly. While some data exist on biomarkers that are related to FEV1, we sought to do a systematic analysis of causal relations of biomarkers with FEV1. Data from the general population-based AGES-Reykjavik stud...

Context: Epidemiological as well as preclinical data support cardiovascular, mainly protective, effects of sex steroids in men, but the mechanisms underlying the cardiovascular actions of sex steroids are poorly understood. Vascular calcification parallels the development of atherosclerosis, but is increasingly recognized as a diversified, highly...

The study aimed to assess whether factors related to cognitive performance were associated with the development of dementia. Additionally, the study aimed to establish whether cognitive performance at baseline or change in cognition between baseline and follow-up (five-year period) had a stronger association with whether an individual would fulfill...

Objective: Twin pregnancies are associated with increased antepartum and intrapartum risks. Limited multiple embryo transfers are associated with decreased twin birth rates. We aimed to study the effect of 2009 Icelandic regulations on twin birth rates and examine obstetric intervention rates for twin births during the study period. Methods: The...

Background. Persistence of physical symptoms after SARS-CoV-2 infection is a major public health concern, although evidence from large observational studies remain scarce. We aimed to assess the prevalence of physical symptoms in relation to acute illness severity up to more than 2-years after diagnosis of COVID-19. Methods. This multinational st...

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6 . Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural an...

Introduction and hypothesis: Pelvic floor dysfunction is common after childbirth. We hypothesize that physiotherapist-guided pelvic floor muscle training (PFMT) is effective regarding pelvic organ prolapse (POP) symptoms during the first postpartum year. Methods: This was a secondary analysis from a randomized controlled trial (RCT), carried out...

Background Little is known regarding the mental health impact of having a significant person (family member and/or close friend) with COVID-19 of different severity. Methods The study included five prospective cohorts from four countries (Iceland, Norway, Sweden, and the UK) with self-reported data on COVID-19 and symptoms of depression and anxiet...

Introduction: Maternal deaths are rare and an indirect measure of the societal framework surrounding pregnancy and childbirth. We surveyed and classified maternal mortality in Iceland using international guidelines, calculating changes over a 40-year period. Material and methods: Information from Statistics Iceland on women aged 15-49 years who...

Smoldering multiple myeloma (SMM) is an asymptomatic precursor to multiple myeloma. Here we define the epidemiological characteristics of SMM in the general population in Iceland. The iStopMM study (ClinicalTrials.gov ID: NCT03327597) is a nationwide screening study for multiple myeloma precursors where all residents in Iceland 40 years or older we...

Serious concerns have been raised about the negative effects of the COVID-19 pandemic on population psychological well-being. However, limited data exist on the long-term effects of the pandemic on incident psychiatric morbidities among individuals with varying exposure to the pandemic. Leveraging prospective data from the community-based UK Bioban...

Background Mental health challenges are on the rise worldwide. In Iceland, little is known about the sociodemographic factors associated with poor mental health. This study aimed to investigate symptoms of depression, anxiety, stress, and psychiatric medication for mental disorders in a nationally representative sample in Iceland and to explore its...

Background Studies of inpatient COVID-19 mortality risk factors have mainly used data from academic medical centers or large multi-hospital databases and have not examined populations with large proportions of Hispanic/Latino patients. In a retrospective cohort study of 4,881 consecutive adult COVID-19 hospitalizations at a single community hospita...

Background: A growing literature, mostly based on selected populations, indicates that traumas may be associated with autoimmune diseases, yet few studies exist on adverse childhood experiences (ACEs) and multiple sclerosis (MS) in the general population. Objective: We assessed cross-sectional associations between self-reported ACEs and MS among...

Background: The association between cardiovascular disease (CVD) and selected psychiatric disorders has frequently been suggested while the potential role of familial factors and comorbidities in such association has rarely been investigated. Methods: We identified 869 056 patients newly diagnosed with CVD from 1987 to 2016 in Sweden with no histor...

Aim To investigate the utility of serum proteins to predict new-onset heart failure (HF), including those with reduced or preserved ejection fraction (HFrEF or HFpEF), with or without the consideration of known HF-associated clinical variables. Methods and results The study included 612 participants with HF events from the prospective population-b...

Background Sexual harassment and violence in the workplace are a serious public health concern for women worldwide with substantial costs due to sick leave and personnel turnover. Yet little is known about the prevalence of sexual harassment and violence at a population level, especially across work sectors. The aim of this study was to investigate...

Hair cortisol concentration (HCC) represent a potential biomarker of chronic psychological stress. Previous studies exploring the association between perceived stress and HCC have been limited to relatively small and selected populations. We collected hair samples from 881 women from the Mexican Teachers’ Cohort (MTC) and 398 women from the Iceland...

Introduction: Educational attainment is related to improved health and longevity. We investigated the relationship between educational attainment and cardiovascular risk factors, subclinical atherosclerosis, and incidence of coronary artery disease. Material and methods: The Reykjavik REFINE study is a population-based study recruiting 6616 subj...

Background The association between cardiovascular disease (CVD) and selected psychiatric disorders has frequently been suggested while inadequate control of familial factors and comorbidities has halted causal inferences. Methods We identified 869 056 patients newly diagnosed with CVD from 1987 to 2016 in Sweden while no history of psychiatric dis...

Objectives To study effects of physiotherapist-guided pelvic floor muscle training on pelvic organ prolapse (POP) early postpartum period. Design Assessor-blinded, randomized controlled trial. Setting Physiotherapy Clinic, Reykjavik. Sample Eighty-four primiparous women with a singleton delivery. Methods Participants were screened for eligibility 6...

Age-related macular degeneration (AMD) is one of the most common causes of visual impairment in the elderly, with a complex and still poorly understood etiology. Whole-genome association studies have discovered 34 genomic regions associated with AMD. However, the genes and cognate proteins that mediate the risk, are largely unknown. In the current...

Title A clinically validated risk calculator for progression of diabetic retinopathy Purpose: Creation of a smart phone application containing diabetic retinopathy risk calculator to empower individual diabetic patients to understand their personal risk factors and risk profile. Educate and motivate patients to influence these risk factors. Me...

The apolipoprotein E allele 4 (APOE-ε4) is established as a major genetic risk factor for cognitive decline and late-onset Alzheimer’s disease. Accumulating evidence has linked ε4 carriership to abnormal structural brain changes across the adult lifespan. To better understand the underlying causal mechanisms, we investigated the extent to which the...

The main purpose of this research is to analyse school principals’ and teachers’ attitudes towards external school evaluation in Iceland, in particular, the ways in which they consider the evaluation affects their schools’ internal evaluation and drives changes in their own practices. The study uses a quantitative method and is based on a survey co...

Study objectives To date, few studies have assessed sleep problems among women residing in Subarctic regions. Therefore, the aim of this large-scale population-based study was to assess the prevalence of severe sleep problems and associated factors among Icelandic women, living at 63-66°N. Methods Participants were 29,681 women (18-69 years old) w...

Rationale Knowledge on biomarkers of interstitial lung disease is incomplete. Interstitial lung abnormalities (ILA) are radiologic changes that may present in its early stages. Objectives To uncover blood proteins associated with ILA using large-scale proteomics methods. Methods Data from two prospective cohort studies, the AGES-Reykjavik study (n=...

Background Long-term mental and physical health consequences of COVID-19 (long COVID) are a persistent public health concern. Little is still known about the long-term mental health of non-hospitalised patients with COVID-19 with varying illness severities. Our aim was to assess the prevalence of adverse mental health symptoms among individuals dia...

Abstract Background Childhood abuse and neglect have been associated with premenstrual disorders (PMDs), including premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). However, the associations of other adverse childhood experiences (ACEs) and the cumulative number of ACEs with PMDs remain to be explored. Methods To evaluate the...

PurposeTo study whether dietary patterns in adolescence are associated with risk of colorectal cancer (CRC).Methods Food frequency data were obtained from the AGES-Reykjavik study, conducted between 2002 and 2006, which included 5,078 (58% women) participants with mean age of 77 (± 5.8) years. Principal component analysis was used to identify dieta...

Background: The COVID-19 pandemic and efforts to contain it have substantially affected the daily lives of most of the world's population. Objective: We describe the impact of the first COVID-19 wave and associated social restrictions on the mental health of a large adult population. Methods: We performed a cohort study nested in a prospective...

Background: Adverse childhood experiences (ACEs) have consistently been associated with elevated risk of multiple adverse health outcomes, yet their contribution to coping ability and psychiatric resilience in adulthood is unclear. Methods: Cross-sectional data were derived from the ongoing Stress-And-Gene-Analysis cohort, representing 30% of th...

Circulating proteins can be used to diagnose and predict disease-related outcomes. A deep serum proteome survey recently revealed close associations between serum protein networks and common disease. In the current study, 54,469 low-frequency and common exome-array variants were compared to 4782 protein measurements in the serum of 5343 individuals...

With the growing number of genetic association studies, the genotype-phenotype atlas has become increasingly more complex, yet the functional consequences of most disease associated alleles is not understood. The measurement of protein level variation in solid tissues and biofluids integrated with genetic variants offers a path to deeper functional...

Background and aims Coronary artery calcium (CAC) and carotid plaque are markers of atherosclerosis and predict future coronary heart disease (CHD) events. The aim of this study was to investigate associations between CAC and carotid plaque in asymptomatic individuals, also in relation to predicted CHD-risk and incident events. A secondary aim was...

Purpose Creation of a smart phone application containing diabetic retinopathy risk calculator to empower individual diabetic patients to understand their personal risk factors and risk profile. Educate and motivate patients to influence these risk factors. Methods A previously validated and published diabetic retinopathy risk algorithm (Aspelund e...

Purpose The aim of this study was to assess the role of the patient’s background and perceived healthcare-related factors in symptoms of acute stress after lung cancer diagnosis. Methods The study population consisted of 89 individuals referred for diagnostic work-up at Landspitali National University Hospital in Iceland and subsequently diagnosed...

Background Women are exposed to a variety of life stressors, particularly violence, during their lifetime which increases the risk of developing various psychiatric and somatic diseases, with dysregulated secretion of cortisol as one potential biological mechanism. We examined the association between violence and other life stressors and hair corti...

BACKGROUND The aim of this multinational study was to assess the development of adverse mental health symptoms among individuals diagnosed with COVID-19 in the general population by acute infection severity up to 16 months after diagnosis. METHODS Participants consisted of 247 249 individuals from seven cohorts across six countries (Denmark, Estoni...

Excessive daytime sleepiness includes both an inability to stay awake during the day and a general feeling of sleepiness. We describe different dimensions of daytime sleepiness in adults with moderate–severe obstructive sleep apnea (OSA) before and after 2 years of positive airway pressure (PAP) treatment. Using the Epworth Sleepiness Scale (score...

Background and Purpose Studies on the association of cerebrovascular risk factors to magnetic resonance imaging detected brain infarcts have been inconsistent, partly reflecting limits of assessment to infarcts anywhere in the brain, as opposed to specific brain regions. We hypothesized that risk-factors may differ depending on where the infarct is...

Key features COVIDMENT [www.covidment.is] is a NordForsk-funded research collaboration across six nations, with the overarching aim to significantly advance current knowledge on mental morbidity trajectories associated with the coronavirus disease 2019 (COVID-19) in the general population and in specific risk groups. From March 2020 through Augus...

Background Smoldering multiple myeloma (SMM) is an asymptomatic precursor condition to multiple myeloma (MM). Emerging data from clinical trials indicate that - compared to watchful monitoring - initiation of therapy at the SMM stage might be indicated. Currently, there is no established screening for SMM in the general population and therefore pat...

Growth rate is regulated by hormonal pathways that might affect early cancer development. We explored the association between rate of growth in height from age 8 to 13 (childhood) years and from age 13 to height at study entry (adolescence), and risk of breast and prostate cancer. Participants were 2,037 Icelanders born 1915 - 1935, who took part i...

Background Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories. Methods We used data from 1990 to 2019 on people aged 30...

Age-related macular degeneration (AMD) is one of the most frequent causes of visual impairment in the elderly population. The overall etiology of AMD is complex and still poorly understood, though age, obesity, smoking, and high-density lipoprotein are known risk factors. In one of the first successful reported genome-wide association studies (GWAS...

Adverse childhood experiences (ACEs) have consistently been associated with elevated risk of multiple adverse health outcomes, yet their contribution to coping ability and psychiatric resilience in adulthood is unclear. Participants were 19,613 women in the Icelandic Stress-And-Gene-Analysis cohort with complete data on 13 ACEs measured with the AC...

With the growing number of genetic association studies, the genotype-phenotype atlas has become increasingly more complex, yet the functional consequences of most disease associated alleles is not understood. The measurement of protein level variation in solid tissues and biofluids integrated with genetic variants offers a path to deeper functional...

The shocking severity of the Covid-19 pandemic has woken up an unprecedented interest and accelerated effort of the scientific community to model and forecast epidemic spreading to find ways to control it regionally and between regions. Here we present a model that in addition to describing the dynamics of epidemic spreading with the traditional co...

Objective To test if patients recovering from COVID-19 are at increased risk of mental morbidities and to what extent such risk is exacerbated by illness severity.Design Population-based cross-sectional study.Setting Iceland.Participants A total of 22 861 individuals were recruited through invitations to existing nationwide cohorts and a social med...

PurposeTo study changes in lung function among individuals with a risk of obstructive sleep apnoea (OSA), and if asthma affected this relationship.Methods We used data from the European Community Respiratory Health Survey II and III, a multicentre general population study. Participants answered questionnaires and performed spirometry at baseline an...

Introduction and hypothesis: To study the prevalence of pelvic floor dysfunction and related bother in primiparous women 6-10 weeks postpartum, comparing vaginal and cesarean delivery. Methods: Cross-sectional study of 721 mothers with singleton births in Reykjavik, Iceland, 2015 to 2017, using an electronic questionnaire. Information on urinary...

Introduction: The number of people with type 2 diabetes has increased in Iceland in the last few decades. We utilized the national database on prescribed medication from the Directorate of Health to estimate the prevalence and incidence of type 2 diabetes in Iceland and made prediction on the prevalence of type 2 diabetes in Iceland in 10 and 20 y...

The 2014–15 Holuhraun eruption in Iceland was the largest fissure eruption in over 200 years, emitting prodigious amounts of gas and particulate matter into the troposphere. Reykjavík, the capital area of Iceland (250 km from eruption site) was exposed to air pollution events from advection of (i) a relatively young and chemically primitive volcani...

Objective Monoclonal gammopathy of undetermined significance (MGUS) is the asymptomatic precursor of multiple myeloma (MM). Lytic bone lesions and fractures are hallmarks of MM and although there are no lytic lesions in MGUS, it has also been associated with fractures. The causes of fractures in MGUS are currently unclear but potential causes inclu...