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Björk, A., Ribom, E., Johansson, G., Scragg, R., Mellstrom, D., Grundberg, E., . . . Kindmark, A. (2019). Variations in the vitamin D receptor gene are not associated with measures of muscle strength, physical performance, or falls in elderly men: Data from MrOS Sweden. Journal of Steroid Biochemistry and Molecular Biology, 187, 160-165
Open this publication in new window or tab >>Variations in the vitamin D receptor gene are not associated with measures of muscle strength, physical performance, or falls in elderly men: Data from MrOS Sweden
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2019 (English)In: Journal of Steroid Biochemistry and Molecular Biology, ISSN 0960-0760, E-ISSN 1879-1220, Vol. 187, p. 160-165Article in journal (Refereed) Published
Abstract [en]

The vitamin D receptor (VDR) has been proposed as a candidate gene for several musculoskeletal phenotypes. However, previous results on the associations between genetic variants of the VDR with muscle strength and falls have been contradictory. The MrOS Sweden survey, a prospective population-based cohort study of 3014 elderly men (mean age 75 years, range 69-81) offered the opportunity to further investigate these associations. At baseline, data were collected on muscle strength and also the prevalence of falls during the previous 12 months. Genetic association analysis was performed for 7 Single Nucleotide Polymorphisms (SNPs), covering the genetic region surrounding the VDR gene in 2924 men with available samples of DNA. Genetic variations in the VDR were not associated with five different measurements of muscle strength or physical performance (hand grip strength right and left, 6 m walking test (easy and narrow) and timed-stands test). However, one of the 7 SNPs of the gene for the VDR receptor, rs7136534, was associated with prevalence of falls (33.6% of the AA, 14.6% of the AG and 16.5% of the GG allele). In conclusion, VDR genetic variants are not related to muscle strength or physical performance in elderly Swedish men. The role of the rs7136534 SNP for the occurrence of falls is not clear.

Keywords
Vitamin D receptor gene, Polymorphisms, Muscle strength, Physical performance, Falls
National Category
Geriatrics Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-379342 (URN)10.1016/j.jsbmb.2018.11.014 (DOI)000459952100021 ()30476589 (PubMedID)
Funder
Swedish Research Council, 2016-01001Knut and Alice Wallenberg Foundation, KAW 2015.0317Torsten Söderbergs stiftelseNovo Nordisk
Available from: 2019-03-15 Created: 2019-03-15 Last updated: 2019-03-15Bibliographically approved
Björk, A., Mellström, D., Ohlsson, C., Karlsson, M., Mallmin, H., Johansson, G., . . . Kindmark, A. (2018). Haplotypes in the CYP2R1 gene are associated with levels of 25(OH)D and bone mineral density, but not with other markers of bone metabolism (MrOS Sweden). PLoS ONE, 13(12), Article ID e0209268.
Open this publication in new window or tab >>Haplotypes in the CYP2R1 gene are associated with levels of 25(OH)D and bone mineral density, but not with other markers of bone metabolism (MrOS Sweden)
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2018 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, no 12, article id e0209268Article in journal (Refereed) Published
Abstract [en]

Objective: Polymorphisms in the CYP2R1 gene encoding Vitamin D 25-hydroxylase have been reported to correlate with circulating levels of 25-OH vitamin D3 (25(OH)D). It is unknown whether these variations also affect overall bone metabolism. In order to elucidate the overall associations of polymorphisms in the CYP2R1, we studied haplotype tagging single nucleotide polymorphisms (SNPs) in the gene and serum levels of 25(OH)D, calcium, phosphate, parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF23), as well as bone mineral density (BMD).

Methods: Baseline data on serum parameters and BMD from MrOS Sweden, a prospective population-based cohort study of elderly men (mean age 75 years, range 69-81), were analyzed. Genotyping was performed for eight SNPs covering the CYP2R1 gene in 2868 men with available samples of DNA. Subjects were followed up concerning incidence of fracture during five years.

Results: There was a significant genetic association with circulating levels of 25(OH)D (4.6-18.5% difference in mean values between SNP alleles), but there were no correlations with levels of calcium, phosphate, PTH or FGF23 for any genetic variant. No differences were found in fracture incidence between the variants. There was an inverse relationship between lower BMD and concomitant higher 25(OH)D for three of the haplotypes (p < 0.005).

Conclusions: Common variants in the CYP2R1 gene encoding Vitamin D 25-hydroxylase correlate with levels of circulating 25(OH)D but do not otherwise associate with measures of calcium and phosphate homeostasis. Presence of the specific haplotypes may be an indicator of risk for low 25(OH)D levels, and may in addition be correlated to bone mineral density.

Place, publisher, year, edition, pages
PUBLIC LIBRARY SCIENCE, 2018
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:uu:diva-373326 (URN)10.1371/journal.pone.0209268 (DOI)000454149400035 ()30576350 (PubMedID)
Funder
Swedish Research Council, 2011-2535
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-01-15Bibliographically approved
Björk, A. (2017). Aspects of Vitamin D: Prevalence of deficiency and impact on musculoskeletal parameters. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Aspects of Vitamin D: Prevalence of deficiency and impact on musculoskeletal parameters
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Vitamin D is central in calcium turnover, and adequate levels are important for skeletal health. It is not clear how large contributions from food and sunlight are in Swedish primary care patients, considering the low radiation of UVB in Sweden and fortification of some foods, and whether differences exist between patients of immigrant and Swedish origin. Increasing incidence of osteoporosis-related fractures is a major global health problem. Genetic variations in metabolising enzymes and in the Vitamin D receptor (VDR) have also been shown to be of importance to the overall effect of vitamin D. Polymorphic variation in the gene CYP2R1 encoding the 25-hydroxylase has previously been reported to correlate with circulating levels of 25(OH)D3. Results of association studies between genetic variants of the VDR and muscle strength, as well as falls have been contradictory.

The purposes of this thesis were to examine possible differences in plasma-25(OH)D3 levels and intake of vitamin D between Swedish and immigrant female primary care patients, to estimate what foods contribute the most, and to identify contributors to vitamin D status (Paper I-II). Furthermore, the relationship between polymorphisms in the CYP2R1 gene and levels of 25(OH)D3 as well as other biochemical parameters (parathyroid hormone, calcium, phosphate and fibroblast growth factor 23) of skeletal homeostasis, bone mineral density and incidence of fractures was investigated (Paper III). Also, the association between genetic variations in the gene for the vitamin D receptor and measures of muscle strength, physical performance and falls (Paper IV), was investigated by using data from a Swedish multicenter study of elderly men (MrOS).

Most important results: Vitamin D deficiency was common, with significant difference between Swedish born and immigrant patients (Paper I). Food intake of vitamin D is associated with circulating vitamin D, but the factors most strongly affecting vitamin D levels were reported sun holiday and origin (Paper II). CYP2R1 polymorphisms are associated with circulating levels of 25(OH)D3 and bone mineral density (Paper III). VDR genetic variants do not appear to have a direct effect on muscle strength or physical performance and incidence of falls in elderly Swedish men (Paper IV).

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. p. 47
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1313
Keywords
Vitamin D, CYP2R1, Vitamin D receptor Gene, Polymorphisms, Muscle Strength
National Category
General Practice
Research subject
Endocrinology and Diabetology
Identifiers
urn:nbn:se:uu:diva-317315 (URN)978-91-554-9852-8 (ISBN)
Public defence
2017-05-04, A1:111a, Biomedicinskt centrum, Uppsala, 13:00 (Swedish)
Opponent
Supervisors
Available from: 2017-04-12 Created: 2017-03-13 Last updated: 2018-01-13
Björk, A., Andersson, Å., Johansson, G., Björkegren, K., Bardel, A. & Kristiansson, P. (2013). Evaluation of sun holiday, diet habits, origin and other factors as determinants of vitamin D status in Swedish primary health care patients: a cross-sectional study with regression analysis of ethnic Swedish and immigrant women. BMC Family Practice, 14, 129
Open this publication in new window or tab >>Evaluation of sun holiday, diet habits, origin and other factors as determinants of vitamin D status in Swedish primary health care patients: a cross-sectional study with regression analysis of ethnic Swedish and immigrant women
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2013 (English)In: BMC Family Practice, ISSN 1471-2296, E-ISSN 1471-2296, Vol. 14, p. 129-Article in journal (Refereed) Published
Abstract [en]

Background

Determinants of vitamin D status measured as 25-OH-vitamin D in blood are exposure to sunlight and intake of vitamin D through food and supplements. It is unclear how large the contributions are from these determinants in Swedish primary care patients, considering the low radiation of UVB in Sweden and the fortification of some foods. Asian and African immigrants in Norway and Denmark have been found to have very low levels, but it is not clear whether the same applies to Swedish patients. The purpose of our study was to identify contributors to vitamin D status in Swedish women attending a primary health care centre at latitude 60°N in Sweden.

Methods

In this cross-sectional, observational study, 61 female patients were consecutively recruited between January and March 2009, irrespective of reason for attending the clinic. The women were interviewed about their sun habits, smoking, education and food intake at a personal appointment and blood samples were drawn for measurements of vitamin D and calcium concentrations.

Results

Plasma concentration of 25-OH-vitamin D below 25 nmol/L was found in 61% (19/31) of immigrant and 7% (2/30) of native women. Multivariate analysis showed that reported sun holiday of one week during the last year at latitude below 40°N with the purpose of sun-bathing and native origin, were significantly, independently and positively associated with 25-OH-vitamin D concentrations in plasma with the strongest association for sun holiday during the past year.

Conclusions

Vitamin D deficiency was common among the women in the present study, with sun holiday and origin as main determinants of 25-OH-vitamin D concentrations in plasma. Given a negative effect on health this would imply needs for vitamin D treatment particularly in women with immigrant background who have moved from lower to higher latitudes.

Keywords: Vitamin D; Sun habits; Immigrant; Women; Primary health care

National Category
General Practice
Identifiers
urn:nbn:se:uu:diva-208596 (URN)10.1186/1471-2296-14-129 (DOI)000324297400001 ()
Available from: 2013-10-04 Created: 2013-10-04 Last updated: 2018-01-19Bibliographically approved
Andersson, A., Björk, A., Kristiansson, P. & Johansson, G. (2013). Vitamin D intake and status in immigrant and native Swedish women: a study at a primary health care centre located at 60 degrees N in Sweden. Food & Nutrition Research, 57, UNSP 20089
Open this publication in new window or tab >>Vitamin D intake and status in immigrant and native Swedish women: a study at a primary health care centre located at 60 degrees N in Sweden
2013 (English)In: Food & Nutrition Research, ISSN 1654-6628, E-ISSN 1654-661X, Vol. 57, p. UNSP 20089-Article in journal (Refereed) Published
Abstract [en]

Background: Immigration to Sweden from lower latitude countries has increased in recent years. Studies in the general population in other Nordic countries have demonstrated that these groups are at risk of developing vitamin D deficiency, but studies in primary health care patients are rare. Objectives: The aim of this study is to examine possible differences in plasma-25(OH)-vitamin D levels and intake of vitamin D between Swedish and immigrant female patients in a primary health care centre located at 60 degrees N, where half of the inhabitants have an immigrant background. Another objective was to estimate what foods contribute with most vitamin D. Design: Thirty-one female patients from the Middle East and Africa and 30 from Sweden were recruited. P-25(OH)D was measured and intake of vitamin D was estimated with a modified food frequency questionnaire (FFQ). Results: Vitamin D deficiency (plasma-25(OH)D<25 nmol/L) was common among immigrant women (61%). One immigrant woman and half of the Swedish women had optimal levels (plasma-25(OH)D>50 nmol/L). There was a positive correlation between the intake of vitamin D from food and plasma-25(OH) D. Only three women, all Swedish, reached the recommended intake of vitamin D from food. The immigrant women had lower intake compared to Swedish women (median: 3.1 vs. 5.1 mu g/day). The foods that contributed with most vitamin D were fatty fish, fortified milk and margarine. Immigrant women consumed less fortified milk and margarine but more meat. Irrespective of origin, patients with plasma-25(OH)D<25 nmol/L consumed less margarine but more meat. Conclusion: Vitamin D deficiency was common in the immigrant patients and their intake of vitamin D was lower. This highlights the need to target information about vitamin D to immigrant women in order to decrease the risk for vitamin D deficiency. The FFQ was well adapted to its purpose to estimate intake of vitamin D.

Keywords
immigrants, vitamin D deficiency, primary health care, food, nutrition requirements
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-203368 (URN)10.3402/fnr.v57i0.20089 (DOI)000319261600001 ()
Available from: 2013-07-09 Created: 2013-07-09 Last updated: 2018-01-19Bibliographically approved
Björk, A., Andersson, K., Kristiansson, P., Björkegren, K., Johansson, G. & Löfvander, M. (2012). Treatment of vitamin D insufficiency in female primary health care patients in Sweden: results from a study at 60N. In: : . Paper presented at Houston Texas 15th Workshop on vitamin D.
Open this publication in new window or tab >>Treatment of vitamin D insufficiency in female primary health care patients in Sweden: results from a study at 60N
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2012 (English)Conference paper, Oral presentation only (Other academic)
National Category
General Practice
Identifiers
urn:nbn:se:uu:diva-245015 (URN)
Conference
Houston Texas 15th Workshop on vitamin D
Available from: 2015-02-24 Created: 2015-02-24 Last updated: 2018-01-19
Björk, A., Venge, P. & Peterson, C. G. (2000). Measurements of ECP in serum and the impact of plasma coagulation. Allergy. European Journal of Allergy and Clinical Immunology, 55(5), 442-448
Open this publication in new window or tab >>Measurements of ECP in serum and the impact of plasma coagulation
2000 (English)In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 55, no 5, p. 442-448Article in journal (Refereed) Published
Abstract [en]

Serum measurement of ECP (eosinophil cationic protein) is used as an indication of eosinophil activation in diseases such as asthma. The levels are dependent on sample handling, since a certain amount of ECP is released during storage. The mechanisms that induce this in vitro release are not known, but are supposed to be related to the coagulation process. The aim of this study was to investigate this further. ECP was measured in EDTA plasma and serum at 22 and 37°C from healthy individuals and patients with asthma and allergy. The serum levels of ECP increased with temperature. Recalcification of citrated plasma in the presence of granulocytes with increasing concentrations of Ca2+ showed a dissociation between the levels of ECP and the occurrence of coagulation. Further experiments indicated that plasma coagulation is not of any importance for the degranulation of eosinophils, nor did the addition of platelets or mononuclear cells affect the ECP levels. Incubations of granulocytes with fresh or frozen plasma and Ca2+suggested the existence of a freezing labile factor in plasma, necessary for the degranulation of healthy eosinophils, but not for allergic/asthmatic eosinophils. Further experiments with pure eosinophils indicated the existence of factors in serum and plasma which facilitate ECP secretion of an active, temperature-dependent nature. We conclude that the raised ECP levels in serum, as compared to EDTA plasma, are unrelated to the coagulation process, but are due to the continuous secretion ex vivo of ECP from active eosinophils. This process is time and temperature dependent and may be facilitated by eosinophil-activating components in the extracellular environment.

National Category
Clinical Laboratory Medicine
Research subject
Clinical Chemistry
Identifiers
urn:nbn:se:uu:diva-208829 (URN)10.1034/j.1398-9995.2000.00272.x (DOI)
Available from: 2013-10-08 Created: 2013-10-08 Last updated: 2017-12-06Bibliographically approved
Björk, A., Eeg-Olofsson, O., Svendsen, P., Moström, U. & Pellettieri, L. (1994). Endovascular treatment of a spinal arteriovenous malformation in a 21-month-old boy. Acta Paediatrica, 83(12), 1326-1331
Open this publication in new window or tab >>Endovascular treatment of a spinal arteriovenous malformation in a 21-month-old boy
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1994 (English)In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 83, no 12, p. 1326-1331Article in journal (Other academic) Published
Abstract [en]

Reports of spinal arteriovenous malformations in children are rare. This case report describes a 21-month-old boy whose first symptom was attacks of abdominal pain, followed gradually by neurological symptoms. The diagnosis was made using magnetic resonance imaging and spinal angiography, and the patient was successfully treated with embolization.

National Category
Pediatrics
Identifiers
urn:nbn:se:uu:diva-208831 (URN)7734884 (PubMedID)
Available from: 2013-10-08 Created: 2013-10-08 Last updated: 2017-12-06Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4411-2322

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