English
norskBlar i forfatter "Horsch, Alexander"
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Analyzing Mitochondrial Morphology Through Simulation Supervised Learning
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-03)The quantitative analysis of subcellular organelles such as mitochondria in cell fluorescence microscopy images is a demanding task because of the inherent challenges in the segmentation of these small and morphologically diverse structures. In this article, we demonstrate the use of a machine learning-aided segmentation and analysis pipeline for the quantification of mitochondrial morphology in ... -
Association between anemia and falls in community-dwelling older people: Cross-sectional results from the KORA-Age study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014) -
The association between anemia and falls in community-living women and men aged 65 years and older from the fifth Tromsø Study 2001-02: a replication study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-27)Background: <br> Falls are common among elderly people, and the risk increase with age. Falls are associated with both health and social consequences for the patient, and major societal costs. Identification of risk factors should be investigated to prevent falls. Previous studies have shown anemia to be associated with increased risk of falling, but the results are inconsistent. The aim of this ... -
Association between objectively measured physical activity and longitudinal changes in body composition in adolescents: the Tromsø study fit futures cohort
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-07)<i>Objectives</i> - Physical activity may be important in deterring the obesity epidemic. This study aimed to determine whether objectively measured physical activity in first year of upper secondary high school predicted changes in body composition over 2 years of follow-up in a cohort of Norwegian adolescents (n=431).<p> <p><i>Design</i> - A longitudinal study of adolescents (mean age of 16 (SD ... -
Associations between Multiple Accelerometry-Assessed Physical Activity Parameters and Selected Health Outcomes in Elderly People - Results from the KORA-Age Study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014) -
Autostrata: Improved Automatic Stratification for Coarsened Exact Matching
(Chapter; Bokkapittel, 2022-08-22)We commonly adjust for confounding factors in analytical observational epidemiologyto reduce biases that distort the results. Stratification and matching are standard methods for reducing confounder bias. Coarsened exact matching (CEM) is a recent method using stratification to coarsen variables into categorical variables to enable exact matching of exposed and nonexposed ... -
Auxiliary Network: Scalable and agile online learning for dynamic system with inconsistently available inputs
(Journal article; Tidsskriftartikkel, 2022-04-13)Streaming classification methods assume the number of input features is fixed and always received. But in many real-world scenarios, some features are reliable while others are unreliable or inconsistent. We propose a novel online deep learning-based model called Auxiliary Network (Aux-Net), which is scalable and agile and can handle any number of inputs at each time instance. The Aux-Net model is ... -
Change in physical activity is not associated with change in mental distress among adolescents: The Tromsø Study: Fit Futures
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-09)<i>Background</i>: Previous research shows that physical activity has a protective effect on mental distress in adults, but the relationship is less researched and seems more ambiguous for adolescents. Studies in this field have typically been cross-sectional by design and based on self-reported physical activity measures, which are known to be vulnerable to response bias. The aim of this study ... -
Collecting health-related research data using consumer-based wireless smart scales
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-14)Background: Serious public-health concerns such as overweight and obesity are in many cases caused by excess intake of food combined with decreases in physical activity. Smart scales with wireless data transfer can, together with smart watches and trackers, observe changes in the population’s health. They can present us with a picture of our metabolism, body health, and disease risks. Combining ... -
Consistent pattern between physical activity measures and chronic pain levels: the Tromsø Study 2015-2016
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-08)Epidemiological literature on the relationship between physical activity and chronic pain is scarce and inconsistent. Hence, our aim was to assess the relationship applying comprehensive methodology, including self-reported and accelerometer measures of physical activity and different severity levels of chronic pain. We used data from the Tromsø Study (2015-2016). All residents in the municipality, ... -
Counterfactual Explainable Gastrointestinal and Colonoscopy Image Segmentation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-26)Segmenting medical images accurately and reliably is crucial for disease diagnosis and treatment. Due to the wide assortment of objects’ sizes, shapes, and scanning modalities, it has become more challenging. Many convolutional neural networks (CNN) have recently been designed for segmentation tasks and achieved great success. This paper presents an optimized deep learning solution using DeepLabv3+ ... -
Criterion validity of the Saltin-Grimby Physical Activity Level Scale in adolescents. The Fit Futures Study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-01)Background<p> <p>The Saltin-Grimby Physical Activity Level Scale (SGPALS) is commonly used to measure physical activity (PA) in population studies, but its validity in adolescents is unknown. This study aimed to assess the criterion validity of the SGPALS against accelerometry in a large sample of adolescents. A secondary aim was to examine the validity across strata of sex, body mass index (BMI), ... -
Criterion validity of two physical activity and one sedentary time questionnaire against accelerometry in a large cohort of adults and older adults
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-26)<i>Objectives</i> - We compared the ability of physical activity and sitting time questionnaires (PAQ) for ranking individuals versus continuous volume calculations (physical activity level (PAL), metabolic equivalents of task (MET), sitting hours) against accelerometry measured physical activity as our criterion.<p> <p><i>Methods</i> - Participants in a cohort from the Tromsø Study completed ... -
Description of spatio-temporal gait parameters in elderly people and their association with history of falls: Results of the population-based cross-sectional KORA-Age study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-25)Background: In this epidemiological study we described the characteristics of spatio-temporal gait parameters among a representative, population-based sample of 890 community-dwelling people aged 65 to 90 years. In addition, we investigated the associations between certain gait parameters and a history of falls in study participants. <p>Methods: In descriptive analyses spatio-temporal gait parameters ... -
Design and evaluation of a computer-based 24-Hour physical activity recall (cpar24) instrument
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-30)<p><i>Background</i>: Widespread access to the Internet and an increasing number of Internet users offers the opportunity of using Web-based recalls to collect detailed physical activity data in epidemiologic studies.</p> <p><i>Objective</i>: The aim of this investigation was to evaluate the validity and reliability of a computer-based 24-hour physical activity recall (cpar24) instrument with ... -
Detection of ground contact times with inertial sensors in elite 100-m sprints under competitive field conditions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-04)This study describes a method for extracting the stride parameter ground contact time (GCT) from inertial sensor signals in sprinting. Five elite athletes were equipped with inertial measurement units (IMU) on their ankles and performed 34 maximum 50 and 100-m sprints. The GCT of each step was estimated based on features of the recorded IMU signals. Additionally, a photo-electric measurement ... -
Documents in medicine. From paper documents to quality-healthcare?
(Chapter; Bokkapittel, 2007) -
Electronic Symptom Reporting Between Patient and Provider for Improved Health Care Service Quality: A Systematic Review of Randomized Controlled Trials. Part 1: State of the Art
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012)Background: Over the last two decades, the number of studies on electronic symptom reporting has increased greatly. However, the field is very heterogeneous: the choices of patient groups, health service innovations, and research targets seem to involve a broad range of foci. To move the field forward, it is necessary to build on work that has been done and direct further research to the areas holding ... -
Electronic Symptom Reporting Between Patient and Provider for Improved Health Care Service Quality: A Systematic Review of Randomized Controlled Trials. Part 2: Methodological Quality and Effects
(Tidsskriftartikkel; Journal article; Peer reviewed, 2012)Background: We conducted in two parts a systematic review of randomized controlled trials (RCTs) on electronic symptom reporting between patients and providers to improve health care service quality. Part 1 reviewed the typology of patient groups, health service innovations, and research targets. Four innovation categories were identified: consultation support, monitoring with clinician support, ... -
Evaluating the performance of raw and epoch non-wear algorithms using multiple accelerometers and electrocardiogram recordings
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-03)Accurate detection of accelerometer non-wear time is crucial for calculating physical activity summary statistics. In this study, we evaluated three epoch-based non-wear algorithms (Hecht, Troiano, and Choi) and one raw-based algorithm (Hees). In addition, we performed a sensitivity analysis to provide insight into the relationship between the algorithms’ hyperparameters and classification performance, ...
