| 1. |
- Björk, Anne
(author)
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Aspects of Vitamin D : Prevalence of deficiency and impact on musculoskeletal parameters
- 2017
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Doctoral thesis (other academic/artistic)abstract
- 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).
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| 2. |
- Björk, Anne, et al.
(author)
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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)
- 2018
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:12
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Journal article (peer-reviewed)abstract
- 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.
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| 3. |
- Björk, Anne, et al.
(author)
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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
- 2019
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In: Journal of Steroid Biochemistry and Molecular Biology. - : Elsevier BV. - 0960-0760 .- 1879-1220. ; 187, s. 160-165
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Journal article (peer-reviewed)abstract
- 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.
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| 4. |
- Bolinder, J., et al.
(author)
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Dapagliflozin maintains glycaemic control while reducing weight and body fat mass over 2 years in patients with type 2 diabetes mellitus inadequately controlled on metformin
- 2014
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In: Diabetes, obesity and metabolism. - : Wiley. - 1462-8902 .- 1463-1326. ; 16:2, s. 159-169
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Journal article (peer-reviewed)abstract
- AimsDapagliflozin, a highly selective inhibitor of sodium-glucose cotransporter 2 (SGLT2), reduces hyperglycaemia and weight in patients with type2 diabetes mellitus (T2DM) by increasing urinary glucose excretion. Long-term glycaemic control, body composition and bone safety were evaluated in patients with T2DM after 102 weeks of dapagliflozin treatment.MethodsThis randomized, double-blind, placebo-controlled study (NCT00855166) enrolled patients with T2DM [mean: age 60.7 years; HbA1c 7.2%; body mass index (BMI) 31.9 kg/m(2); body weight 91.5 kg] inadequately controlled on metformin. Patients (N=182) were randomly assigned 1:1 to receive dapagliflozin 10 mg/day or placebo added to open-label metformin for a 24-week double-blind treatment period followed by a 78-week site- and patient-blinded extension period. At week 102, changes from baseline in HbA1c, weight, waist circumference, total body fat mass as measured by dual-energy X-ray absorptiometry (DXA), serum markers of bone turnover, bone mineral density (BMD) as measured by DXA, and adverse events were evaluated.ResultsA total of 140 patients (76.9%) completed the study. Over 102 weeks, dapagliflozin-treated patients showed reductions in HbA1c by -0.3%, weight by -4.54 kg, waist circumference by -5.0 cm and fat mass by -2.80 kg without increase in rate of hypoglycaemia. Compared with placebo, no meaningful changes from baseline in markers of bone turnover or BMD were identified over 102 weeks. One fracture occurred in each treatment group. The frequency of urinary tract infection (UTI) and genital infection was similar in both treatment groups.ConclusionsOver 102 weeks, dapagliflozin improved glycaemic control, and reduced weight and fat mass, without affecting markers of bone turnover or BMD in patients with T2DM inadequately controlled on metformin.
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| 5. |
- Bolinder, Jan, et al.
(author)
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Effects of dapagliflozin on body weight, total fat mass, and regional adipose tissue distribution in patients with type 2 diabetes mellitus with inadequate glycemic control on metformin
- 2012
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In: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 97:3, s. 1020-1031
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Journal article (peer-reviewed)abstract
- Context:Dapagliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, reduces hyperglycemia in patients with type 2 diabetes mellitus (T2DM) by increasing urinary glucose excretion, and weight loss is a consistent associated finding.Objectives:Our objectives were to confirm weight loss with dapagliflozin and establish through body composition measurements whether weight loss is accounted for by changes in fat or fluid components.Design and Setting:This was a 24-wk, international, multicenter, randomized, parallel-group, double-blind, placebo-controlled study with ongoing 78-wk site- and patient-blinded extension period at 40 sites in five countries.Patients:Included were 182 patients with T2DM (mean values: women 63.3 and men 58.6 yr of age; hemoglobin A1c 7.17%, body mass index 31.9 kg/m2, and body weight 91.5 kg) inadequately controlled on metformin.Intervention:Dapagliflozin 10 mg/d or placebo was added to open-label metformin for 24 wk.Main Outcome Measures:Primary endpoint was total body weight (TBW) change from baseline at wk 24. Key secondary endpoints were waist circumference and dual-energy x-ray absorptiometry total-body fat mass (FM) changes from baseline at wk 24, and patient proportion achieving body weight reduction of at least 5% at wk 24. In a subset of patients, magnetic resonance assessment of visceral adipose tissue (VAT) and sc adipose tissue (SAT) volume and hepatic lipid content were also evaluated.Results:At wk 24, placebo-corrected changes with dapagliflozin were as follows: TBW, −2.08 kg [95% confidence interval (CI) = −2.84 to −1.31; P < 0.0001]; waist circumference, −1.52 cm (95% CI = −2.74 to −0.31; P = 0.0143); FM, −1.48 kg (95% CI = −2.22 to −0.74; P = 0.0001); proportion of patients achieving weight reduction of at least 5%, +26.2% (95% CI = 15.5 to 36.7; P < 0.0001); VAT, −258.4 cm3 (95% CI = −448.1 to −68.6; nominal P = 0.0084); SAT, −184.9 cm3 (95% CI = −359.7 to −10.1; nominal P = 0.0385). In the dapagliflozin vs. placebo groups, respectively, serious adverse events were reported in 6.6 vs. 1.1%; events suggestive of vulvovaginitis, balanitis, and related genital infection in 3.3 vs. 0%; and lower urinary tract infections in 6.6 vs. 2.2%.Conclusions:Dapagliflozin reduces TBW, predominantly by reducing FM, VAT and SAT in T2DM inadequately controlled with metformin.
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| 6. |
- Harvey, Nicholas C., et al.
(author)
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Falls Predict Fractures Independently of FRAX Probability : A Meta-Analysis of the Osteoporotic Fractures in Men (MrOS) Study
- 2018
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In: Journal of Bone and Mineral Research. - : WILEY. - 0884-0431 .- 1523-4681. ; 33:3, s. 510-516
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Journal article (peer-reviewed)abstract
- Although prior falls are a well-established predictor of future fracture, there is currently limited evidence regarding the specific value of falls history in fracture risk assessment relative to that of other clinical risk factors and bone mineral density (BMD) measurement. We therefore investigated, across the three Osteoporotic Fractures in Men (MrOS) Study cohorts, whether past falls predicted future fracture independently of FRAX and whether these associations varied with age and follow-up time. Elderly men were recruited from MrOS Sweden, Hong Kong, and USA. Baseline data included falls history (over the preceding 12 months), clinical risk factors, BMD at femoral neck, and calculated FRAX probabilities. An extension of Poisson regression was used to investigate the associations between falls, FRAX probability, and incident fracture, adjusting for age, time since baseline, and cohort in base models; further models were used to investigate interactions with age and follow-up time. Random-effects meta-analysis was used to synthesize the individual country associations. Information on falls and FRAX probability was available for 4365 men in USA (mean age 73.5 years; mean follow-up 10.8 years), 1823 men in Sweden (mean age 75.4 years; mean follow-up 8.7 years), and 1669 men in Hong Kong (mean age 72.4 years; mean follow-up 9.8 years). Rates of past falls were similar at 20%, 16%, and 15%, respectively. Across all cohorts, past falls predicted incident fracture at any site (hazard ratio [HR]=1.69; 95% confidence interval [CI] 1.49, 1.90), major osteoporotic fracture (MOF) (HR=1.56; 95% CI 1.33, 1.83), and hip fracture (HR=1.61; 95% CI 1.27, 2.05). Relationships between past falls and incident fracture remained robust after adjustment for FRAX probability: adjusted HR (95% CI) any fracture: 1.63 (1.45, 1.83); MOF: 1.51 (1.32, 1.73); and hip: 1.54 (1.21, 1.95). In conclusion, past falls predicted incident fracture independently of FRAX probability, confirming the potential value of falls history in fracture risk assessment.
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| 7. |
- Harvey, N. C., et al.
(author)
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FRAX predicts incident falls in elderly men : findings from MrOs Sweden
- 2016
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In: Osteoporosis International. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 27:1, s. 267-274
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Journal article (peer-reviewed)abstract
- A Summary Falls and fractures share several common risk factors. Although past falls is not included as an input variable in the FRAX calculator, we demonstrate that FRAX probability predicts risk of incident falls in the MrOs Sweden cohort. Introduction Although not included in the FRAXA (R) algorithm, it is possible that increased falls risk is partly dependent on other risk factors that are incorporated into FRAX. The aim of the present study was to determine whether fracture probability generated by FRAX might also predict risk of incident falls and the extent that a falls history would add value to FRAX. Methods We studied the relationship between FRAX probabilities and risk of falls in 1836 elderly men recruited to the MrOS study, a population-based prospective cohort of men from Sweden. Baseline data included falls history, clinical risk factors, bone mineral density (BMD) at femoral neck, and calculated FRAX probabilities. Incident falls were captured during an average of 1.8 years of follow-up. An extension of Poisson regression was used to investigate the relationship between FRAX, other risk variables, and the time-to-event hazard function of falls. All associations were adjusted for age and time since baseline. Results At enrolment, 15.5 % of the men had fallen during the preceding 12 months (past falls) and 39 % experienced one or more falls during follow-up (incident falls). The risk of incident falls increased with increasing FRAX probabilities at baseline (hazard ratio (HR) per standard deviation (SD), 1.16; 95 % confidence interval (95%CI), 1.06 to 1.26). The association between incident falls and FRAX probability remained after adjustment for past falls (HR per SD, 1.12; 95%CI, 1.03 to 1.22). High compared with low baseline FRAX score (>15 vs <15 % probability of major osteoporotic fracture) was strongly predictive of increased falls risk (HR, 1.64; 95%CI, 1.36 to 1.97) and remained stable with time. Whereas past falls were a significant predictor of incident falls (HR, 2.75; 95%CI, 2.32 to 3.25), even after adjustment for FRAX, the hazard ratio decreased markedly with increasing follow-up time. Conclusions Although falls are not included as an input variable, FRAX captures a component of risk for future falls and outperforms falls history with an extended follow-up time.
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