Publications by authors named "Sigridur Gudmundsdottir"

Problematic low energy availability (LEA) is the underlying cause of relative energy deficiency in sport (REDs). Male specific etiology, as well as the duration and degree of LEA exposures resulting in REDs remain to be adequately described. The present study aimed to assess occurrences of LEA (energy availability [EA] <25 kcal/kg fat-free mass/day) in male athletes from various sports over 7 days.

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Background: Problematic low energy availability (EA) is the underlying culprit of relative energy deficiency in sport (REDs), and its consequences have been suggested to be exacerbated when accompanied by low carbohydrate (CHO) intakes.

Objectives: This study compared dietary intake, nutrition status and occurrence of REDs symptoms in groups of female athletes, displaying different patterns of EA and CHO intake.

Methods: Female athletes ( = 41, median age 20.

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Article Synopsis
  • Sedentary behavior (SB), or prolonged sitting, has been linked to various health issues, particularly regarding bone health, but there is a lack of population-based data on its long-term impact on bone density and fracture risk.
  • The study assessed the relationship between daily sitting time, bone mineral density (BMD) measured via DXA, and the incidence of low-trauma fractures in a diverse group of over 8,000 participants in Canada aged 25 to 80+.
  • The findings indicated that while increased SB was associated with lower baseline BMD in certain groups, it did not correlate with significant changes in BMD or an increased risk of fractures over a 10-year period.
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Objectives: Disordered eating and compulsive exercise behaviours are common among athletes and can increase the risk of relative energy deficiency in sport (REDs). Contrarily, the prevalence of muscle dysmorphia and its relationship with REDs are unknown. This cross-sectional study aimed to evaluate associations of all three with REDs symptoms.

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Background: Side effects of breast cancer treatment may persist long into survivorship, reducing quality of life (QOL) in patients with breast cancer and survivors. There is growing evidence for the use of digital health technologies, such as mobile apps, to support self-management, decrease symptom burden, and improve QOL in patients with cancer. However, an updated overview of the effects of mobile apps on QOL and well-being in patients with breast cancer and survivors is needed.

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Background: Patients with atopic dermatitis can experience chronic eczema with pruritus, skin pain, sleep problems, anxiety, and other problems that reduce their quality of life (QoL). Current treatments aim to improve these symptoms and reduce inflammation, but poor treatment adherence and disease understanding are key concerns in the long-term management of atopic dermatitis. Digital therapeutics can help with these and support patients toward a healthier lifestyle to improve their overall QoL.

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Introduction: Improving disease awareness and treatment adherence is key for the long-term management of atopic dermatitis (AD). Digital interventions can support patients in disease self-management and adopting a healthier lifestyle through behavioral modifications. We aimed to test the clinical efficacy of a digital program in patients with AD.

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Studies of adolescent body image and screen use are mostly limited to girls, and longitudinal data are scarce. We examined cross-sectional and longitudinal associations between these variables in mid-adolescent boys and girls. Data was collected when participants were at age 15 and 17, by questionnaire and objective measurements ( = 152 had complete data).

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In laboratory studies, imposed sleep restriction consistently reduces cognitive performance. However, the association between objectively measured, free-living sleep and cognitive function has not been studied in older adolescents. To address this gap, we measured one week of sleep with a wrist-worn GT3X+ actigraph in 160 adolescents (96 girls, 17.

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Fulfilling individual energy and nutrient requirements is of great importance for athletes to support overall health and well-being, training adaptation, recovery and injury prevention. Energy availability is the amount of energy left over and available for bodily functions after the energy expended for training is subtracted from the energy taken in from food. The syndrome of Relative Energy Deficiency in Sport (RED-s) refers to the multifactorial health and performance consequences of low energy availability.

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Objectives: Sleep duration and physical activity decline with age during adolescence. Earlier school schedules may contribute to these declines. The aim of this longitudinal study was to track changes in sleep and activity of Icelandic youth from primary to secondary school and compare students who enrolled in secondary schools with traditional and college-style schedules.

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Background: Sleep and physical activity are modifiable behaviors that play an important role in preventing overweight, obesity, and metabolic health problems. Studies of the association between concurrent objective measures of sleep, physical activity, and metabolic risk factors among adolescents are limited.

Objective: The aim of the study was to examine the association between metabolic risk factors and objectively measured school day physical activity and sleep duration, quality, onset, and variability in adolescents.

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Objectives: Emerging evidence suggests that inconsistent sleep may affect physical and psychological health. Thus, it is important to identify modifiable determinants of sleep variability. Screen time and physical activity are both thought to affect sleep, but studies of their relationship to sleep variability using objective measures are lacking.

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The commercial production of lumpfish L. is expanding with the increased demand for their use as cleaner fish, to control sea-lice numbers, at marine Atlantic salmon L. aquaculture sites throughout Northern Europe.

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Introduction: Sleep is often quantified using self-report or actigraphy. Self-report is practical and less technically challenging, but prone to bias. We sought to determine whether these methods have comparable sensitivity to measure longitudinal changes in adolescent bedtimes.

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Purpose: Insufficient sleep duration may affect athletic performance and health. Inconsistent sleep pattern also has negative health effects, but studies on athletes' intraindividual sleep variability are scarce. The aim of this research was to compare total sleep time (TST) and variability (TST-variability), wakening after sleep onset, and sleep efficiency, during nights preceding early morning practices with other nights, and to investigate sleep characteristics of nights following a day with early morning only, evening only, or both a morning and an evening session in adolescent swimmers.

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Extracellular vesicles are released from cells and participate in cell communication via transfer of protein and genetic cargo derived from the parent cells. EVs play roles in normal physiology and immunity and are also linked to various pathological processes. Peptidylarginine deiminases (PADs) are phylogenetically conserved enzymes with physiological and pathophysiological roles.

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A novel 27 kDa ladder-lectin-like protein, showing a multimeric structure under non-reducing conditions, was isolated from halibut serum by binding to N-acetyl glucosamine. Mass-spectrometry analysis did not show significant homology with known proteins. Specific antibodies were produced and used in immunohistochemistry on tissue sections of early halibut ontogeny from 119 until 1050 °d post hatching.

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A novel viral haemorrhagic septicaemia virus (VHSV) of genotype IV was isolated from wild lumpfish (Cyclopterus lumpus), brought to a land-based farm in Iceland, to serve as broodfish. Two groups of lumpfish juveniles, kept in tanks in the same facility, got infected. The virus isolated was identified as VHSV by ELISA and real-time RT-PCR.

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Post-translational protein deimination is mediated by peptidylarginine deiminases (PADs), which are calcium dependent enzymes conserved throughout phylogeny with physiological and pathophysiological roles. Protein deimination occurs via the conversion of protein arginine into citrulline, leading to structural and functional changes in target proteins. In a continuous series of early halibut development from 37 to 1050° d, PAD, total deiminated proteins and deiminated histone H3 showed variation in temporal and spatial detection in various organs including yolksac, muscle, skin, liver, brain, eye, spinal cord, chondrocytes, heart, intestines, kidney and pancreas throughout early ontogeny.

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Peptidylarginine deiminases (PADs) are calcium dependent enzymes with physiological and pathophysiological roles conserved throughout phylogeny. PADs promote post-translational deimination of protein arginine to citrulline, altering the structure and function of target proteins. Deiminated proteins were detected in the early developmental stages of cod from 11 days post fertilisation to 70 days post hatching.

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Aim: The associations between body fat levels and physical activity with academic performance are inconclusive and were explored using longitudinal data.

Methods: We enrolled 134/242 adolescents aged 15, who were studied at the age of nine and agreed to be followed up from April to May 2015 for the Health behaviours of Icelandic youth study. Accelerometers measured physical activity, body mass indexes (BMI) were calculated and dual-energy X-ray absorptiometry scans assessed the participants' body composition at nine and 15.

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Pentraxins are fluid phase pattern recognition molecules that form an important part of the innate immune defence and are conserved between fish and human. In Atlantic cod (Gadus morhua L.), two pentraxin-like proteins have been described, CRP-I and CRP-II.

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Objective: Few studies have explored the potential interrelated associations of screen time and physical activity with mental health in youth, particularly using objective methods. We examined cross-sectional associations of these variables among Icelandic adolescents, using objective and subjective measurements of physical activity.

Methods: Data were collected in the spring of 2015 from 315 tenth grade students (mean age 15.

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Introduction: Physical activity and sleep are major determinants of overall health. According to international recommendations, adolescents should engage in moderate to vigorous physical activity for at least 60 min each day and sleep eight to ten hours each night. The association between physical activity and sleep in adolescents is not well known.

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