• Alanine aminotransferase and body composition in obese men and women 

      Bekkelund, Svein Ivar; Jorde, Rolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-26)
      There is a known relationship between serum alanine aminotransferase (ALT) and obesity in humans, but the mechanism(s) are not clarified. This study investigated the associations between serum ALT and body composition in an overweight and obese population. The results are based on data from a previous randomized controlled trial treating obesity with vitamin D<sub>3</sub>. A sample of 448 overweight ...
    • Assessing the relationship between perfluoroalkyl substances, thyroid hormones and binding proteins in pregnant women; a longitudinal mixed effects approach 

      Berg, Vivian; Nøst, Therese Haugdahl; Hansen, Solrunn; Elverland, Astrid; Veyhec, Anna-Sofía; Jorde, Rolf; Odland, Jon Øyvind; Sandanger, Torkjel M (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-04)
      <p>The mechanisms involved in thyroid homeostasis are complex, and perfluoroalkyl substances (PFASs) have been indicated to interfere at several levels in this endocrine system. Disruption of the maternal thyroid homeostasis during early pregnancy is of particular concern, where subclinical changes in maternal thyroid hormones (THs) may affect embryonic and foetal development.</p> <p>The present ...
    • Association of vitamin D status with arterial blood pressure and hypertension risk: A mendelian randomisation study 

      Vimaleswaran, Kerani S.; Cavadino, Alana; Berry, Diane J.; Jorde, Rolf; Grimnes, Guri; Dieffenbach, Aida Karina; Lu, Chen; Alves, Alexessander Couto; Heerspink, Hiddo J. Lambers; Tikkanen, Emmi; Eriksson, Joel; Wong, Andrew; Mangino, Massimo; Jablonski, Kathleen A.; Nolte, Ilja M.; Houston, Denise K.; Ahluwalia, Tarunveer Singh; van der Most, Peter J.; Pasko, Dorota; Zgaga, Lina; Thiering, Elisabeth; Schöttker, B; Saum, KU; Brenner, H; Järvelin, MR; Tzoulaki, I; Snieder, H; Stolk, RP; Hartman, CA; de Boer, RA; van der Harst, P; Navis, G; de Borst, MH; Lorentzon, M; Mellström, D; Ohlsson, C; Hardy, R; Kuh, D; Cooper, JA; Acharya, J; Humphries, SE; Hingorani, AD; Kumari, M; Kivimaki, M; Spector, TD; Kritchevsky, SB; Lohman, KK; Sørensen, TIA; Frayling, TM; Campbell, H; Theodoratou, E; Fraser, RM; Wilson, JF; Rudan, I; Price, JF; McLachlan, S; Vitart, V; Navarro, P; Huffman, JE; Hayward, C; Wright, AF; Tiesler, CMT; Heinrich, J; McCarthy, MI; Ingelsson, E; Arden, N; Cooper, C; Dupuis, J; Herzig, KH; Sebert, S; Pouta, A; Laitinen, J; Kleber, ME; März, W; Jameson, K; Osmond, C; Raitakari, O; Ripatti, S; Lahti, J; Eriksson, JG; Penninx, BW; Billings, LK; Florez, JC; Rejnmark, L; Langdahl, BL; Paternoster, L; Hernandez, DG; Byberg, L; Michaelsson, K; Hagström, E; Melhus, H; Ljunggren, O; Lind, L; Jula, A; Polasek, O; Salomaa, V; Karlsson, M; Bandinelli, S; Lehtimäki, T; Wang, TJ; Pilz, S; Whittaker, JC (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-25)
      Background Low plasma 25-hydroxyvitamin D (25[OH]D) concentration is associated with high arterial blood pressure and hypertension risk, but whether this association is causal is unknown. We used a mendelian randomisation approach to test whether 25(OH)D concentration is causally associated with blood pressure and hypertension risk.<p> <p>Methods In this mendelian randomisation study, we generated ...
    • Associations of serum 25-hydroxyvitamin D and subjective sleep measures in an arctic population: Insights from the population-based Tromsø Study 

      Uhlving Larsen, Anette; Hopstock, Laila Arnesdatter; Jorde, Rolf; Grimnes, Guri (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-06)
      Objective - To investigate the relation between serum 25-hydroxyvitamin D (s-25(OH)D) and subjective sleep measures in an Arctic population (69°N).<p> <p>Methods - Cross-sectional data was collected from 21,083 individuals (aged ≥40 years) participating in the population based Tromsø Study: Tromsø7 (2015–2016). The present study included 20,438 participants, after having excluded respondents ...
    • Bone mineral density at the hip and its relation to fat mass and lean mass in adolescents: the Tromsø Study, Fit Futures 

      Winther, Anne; Jørgensen, Lone; Ahmed, Luai A.; Christoffersen, Tore; Furberg, Anne-Sofie; Grimnes, Guri; Jorde, Rolf; Nilsen, Ole-Andreas; Dennison, Elaine M.; Emaus, Nina (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-19)
      <p><i>Background</i>: Positive association between body weight and bone mass is well established, and the concept of body mass index (BMI) is associated with higher areal bone mineral density (aBMD) and reduced fracture risk. BMI, that comprises both fat mass (FM) and lean mass (LM) may contribute to peak bone mass achievement in different ways. This study explored the influence of body composition ...
    • Bone mineral density is associated with Vitamin D related rs6013897 and estrogen receptor polymorphism rs4870044: The Tromsø study 

      Martinaityte, Ieva; Jorde, Rolf; Emaus, Nina; Eggen, Anne Elise; Joakimsen, Ragnar Martin; Kamycheva, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-02)
      Background:<br>Bone mineral density (BMD) is determined by bone remodeling processes regulated by endocrine, autocrine and genetic mechanisms. Thus, some studies have reported that BMD is associated with single nucleotide polymorphisms (SNPs) associated with vitamin D receptor (VDR), serum 25(OH)D levels and estrogen receptor 1 (ESR1), but without consensus. Therefore, we aimed to map and compare ...
    • Changes in the human transcriptome upon vitamin D supplementation 

      Pasing, Yvonne; Fenton, Christopher Graham; Jorde, Rolf; Paulssen, Ruth H (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-19)
      Vitamin D is hydroxylated in the liver and kidneys to its active form, which can bind to the vitamin D receptor (VDR). The VDR is present in a wide variety of different cells types and tissues and acts as a transcription factor. Although activation of the VDR is estimated to regulate expression of up to 5% of the human genome, our study is the first analysing gene expression after supplementation ...
    • Combined hormonal contraceptives and vitamin D metabolism in adolescent girls 

      Öberg, Eva Gunnel Johanna; Jorde, Rolf; Figenschau, Professor Yngve; Thorsby, Per Medbøe; Dahl, Sandra Rinne; Winther, Anne; Grimnes, Guri (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-31)
      Objective: Combined hormonal contraceptive (CHC) use has been associated with higher total 25-hydroxyvitamin D (25(OH)D) levels. Here, we investigate the relation between CHC use and vitamin D metabolism to elucidate its clinical interpretation. <p>Methods: The cross-sectional Fit Futures 1 included 1038 adolescents. Here, a subgroup of 182 girls with available 25(OH)D, 1,25-dihydroxyvitamin D ...
    • The DBP Phenotype Gc-1f/Gc-1f is associated with reduced risk of cancer. The Tromsø Study 

      Jorde, Rolf; Schirmer, Henrik; Wilsgaard, Tom; Mathiesen, Ellisiv B.; Løchen, Maja-Lisa; Joakimsen, Ragnar Martin; Grimnes, Guri (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-18)
      Background and Objective In addition to its role as a transport protein, the vitamin D binding protein (DBP) may also affect lipid metabolism, inflammation and carcinogenesis. There are three common variants of the DBP, Gc1s (1s), Gc1f (1f), Gc2 (2) that result in six common phenotypes (1s/1s, 1s/ 1f, 1s/2, 1f/1f, 1f/2, and 2/2). These phenotypes can be identified by genotyping for the two single ...
    • Effect of genetically low 25-hydroxyvitamin D on mortality risk: Mendelian randomization analysis in 3 large European cohorts 

      Aspelund, Thor; Grübler, Martin R.; Smith, Albert V.; Gudmundsson, Elias F.; Keppel, Martin; Cotch, Mary Frances; Harris, Tamara B.; Jorde, Rolf; Grimnes, Guri; Joakimsen, Ragnar Martin; Schirmer, Henrik; Wilsgaard, Tom; Mathiesen, Ellisiv B.; Njølstad, Inger; Løchen, Maja-Lisa; März, Winfried; Kleber, Marcus E.; Tomaschitz, Andreas; Grove-Laugesen, Diana; Rejnmark, Lars; Swart, Karin M.A.; Brouwer, Ingeborg A.; Lips, Paul; van Schoor, Natasja M.; Sempos, Christopher T.; Durazo-Arvizu, Ramón A.; Škrabáková, Zuzana; Dowling, Kirsten G.; Cashman, Kevin D.; Kiely, Mairead; Pilz, Stefan; Gudnason, Vilmundur; Eiríksdóttir, Gudny (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-02)
      The aim of this study was to determine if increased mortality associated with low levels of serum 25-hydroxyvitamin D (25(OH)D) reflects a causal relationship by using a Mendelian randomisation (MR) approach with genetic variants in the vitamin D synthesis pathway. Individual participant data from three European cohorts were harmonized with standardization of 25(OH)D according to the Vitamin D ...
    • The effect of high-dose vitamin D3 supplementation on bone mineral density in subjects with prediabetes 

      Larsen, Anette Uhlving; Grimnes, Guri; Jorde, Rolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-18)
      <p><i>Summary</i> The rationale of this study was to determine the effect of high-dose vitamin D3 supplementation on bone mineral density (BMD). Prediabetic males given vitamin D had significantly less reduction in BMD at the femoral neck compared to the controls. The clinical implications of our findings require further investigation.</p> <p><i>Introduction</i> Type 2 diabetes mellitus is ...
    • Effects of vitamin D supplementation on bone turnover markers and other bone-related substances in subjects with vitamin D deficiency 

      Jorde, Rolf; Stunes, Astrid Kamilla; Kubiak, Julia Magdalena; Joakimsen, Ragnar Martin; Grimnes, Guri; Thorsby, Per Medbøe; Syversen, Unni (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-05)
      In observational studies, vitamin D deficiency is a risk factor for low bone density and future fractures, whereas a causal relation has been difficult to show in randomized controlled trials (RCTs). Similarly, vitamin D deficiency has been associated with increased bone turnover, but RCTs with vitamin D have not shown conclusive effects. This could be due to inclusion of vitamin D sufficient subjects ...
    • Effects of Age and Sex on Estimated Diabetes Prevalence Using Different Diagnostic Criteria: The Tromso OGTT Study 

      Hutchinson, Moira Strand; Joakimsen, Ragnar Martin; Njølstad, Inger; Schirmer, Henrik; Figenschau, Yngve Anton; Svartberg, Johan; Jorde, Rolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Hb 6.5% has recently been recommended as an alternative diagnostic criterion for diabetes. The aims of the study were to evaluate the effects of age, sex, and other factors on prevalence of diabetes and to compare risk profiles of subjects with diabetes when defined by Hb and glucose criteria. Subjects were recruited among participants in the longitudinal population-based Tromsø Study. Hb , fasting ...
    • Effects of Vitamin D binding protein phenotypes and Vitamin D supplementation on serum total 25(OH)D and directly measured free 25(OH)D 

      Sollid, Stina Therese; Strand Hutchinson, Moira; Berg, Vivian; Fuskevåg, Ole-Martin; Figenschau, Yngve Anton; Thorsby, Per Medbøe; Jorde, Rolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-05)
      Objective:<br>To determine the relationship between serum total 25-hydroxyvitamin D (25(OH)D), directly measured free 25(OH)D and calculated free 25(OH)D with regard to vitamin D-binding protein (DBP) phenotypes, sex, BMI, age and season, and their interrelationship to vitamin D supplementation.<br>Design, patients and interventions:<br>A randomized controlled trial with 20 000 IU of vitamin D3 per ...
    • Evaluation of Serum 25-Hydroxyvitamin D as a Predictor of Carotid Intima-Media Thickness and Carotid Total Plaque Area in Nonsmokers: The Tromso Study 

      Kamycheva, Elena; Johnsen, Stein Harald; Wilsgaard, Tom; Jorde, Rolf; Mathiesen, Ellisiv B. (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Objective. Altered calcium homeostasis has been linked to increased intima-media thickness (IMT) and plaques. We aimed to investigate whether serum 25-hydroxyvitamin D (25(OH)D) and serum calcium are associated with IMT and plaques in nonsmoking population. Methods.Ultrasound of the right carotid arterywith themeasurements of IMT and plaqueswas performed in 4194 nonsmoking subjects with available ...
    • Four months vitamin D supplementation to vitamin D insufficient individuals does not improve muscular strength: A randomized controlled trial 

      Grimnes, Guri; Kubiak, Julia Magdalena; Jorde, Rolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-16)
      <i>Main objective</i> - The inconsistent results on the effects of vitamin D on muscle strength reported by intervention trials may partly be explained by inclusion of vitamin D sufficient individuals. The main objective was to study whether vitamin D supplementation will improve muscle strength in men and women with low serum vitamin D status, as measured by 25-hydroxyvitamin D (25(OH)D) at ...
    • Genetic variations in the Vitamin D receptor predict type 2 diabetes and myocardial infarction in a community-based population: The tromsø study 

      Zostautiene, Leva; Jorde, Rolf; Schirmer, Henrik; Mathiesen, Ellisiv B.; Njølstad, Inger; Løchen, Maja-Lisa; Wilsgaard, Tom; Joakimsen, Ragnar Martin; Kamycheva, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-23)
      Background Though the associations between low serum 25-hydroxyvitamin D (25(OH)D) levels and health outcomes such as type 2 diabetes (T2D), myocardial infarction (MI), cancer, and mortality are well-studied, the effect of supplementation with vitamin D is uncertain. This may be related to genetic differences. Thus, rs7968585, a single nucleotide polymorphism (SNP) of the vitamin D receptor ...
    • Hyperglycemia, Assessed by HbA1c, and Future Risk of Venous Thromboembolism - The Tromsø Study 

      Lerstad, Gunhild; Brodin, Ellen Elisabeth; Enga, Kristin; Jorde, Rolf; Schirmer, Henrik; Njølstad, Inger; Svartberg, Johan; Brækkan, Sigrid Kufaas; Hansen, John-Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-03-05)
      Background: Glycated hemoglobin (HbA1c), a marker of average plasma glucose during the last 8-12 weeks, is associated with future risk of cardiovascular disease (CVD) and all-cause mortality. Objectives: To examine the association between hyperglycemia, assessed by HbA1c, and future risk of VTE in a population based cohort. Methods: HbA1c was measured in 16 156 unique subjects (25-87 years) ...
    • Increased calcium intake is associated lower serum 25-hydroxyvitamin D levels in subjects with adequate vitamin D intake: a population-based observational study 

      Jorde, Rolf; Grimnes, Guri (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-02)
      <i>Background</i> - There are indications that an increased intake of calcium has a vitamin D sparing effect, which might be explained by a decreased catabolism of 25-hydroxyvitamin D (25(OH)D). However, there are only a few studies where this has been examined.<p> <p><i>Method</i> - In the seventh survey of the Tromsø study, serum 25(OH)D and parathyroid hormone were measured, and questionnaires ...
    • Leisure time computer use and adolescent bone health - findings from the Tromsø Study, Fit Futures: a cross sectional study 

      Winther, Anne; Ahmed, Luai Awad; Furberg, Anne-Sofie; Grimnes, Guri; Jorde, Rolf; Nilsen, Ole-Andreas; Dennison, Elaine; Emaus, Nina (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-20)
      <p>Objectives: Low levels of physical activity may have considerable negative effects on bone health in adolescence, and increasing screen time in place of sporting activity during growth is worrying. This study explored the associations between self-reported screen time at weekends and bone mineral density (BMD). <p>Design: In 2010/2011, 1038 (93%) of the region’s first-year upper-secondary ...