oru.sePublikationer
Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Vitamin D and its role in obesity and other associated conditions
Örebro universitet, Institutionen för medicinska vetenskaper.
2018 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Vitamin D has received much attention in recent years due to the re-emergence of vitamin D deficiency as a global health issue along with increasing evidence indicating that 1,25-dihydroxivitamin D, the hormonally active form of vita-min D, not only acts in calcium and bone metabolism but also generates ex-traskeletal biological responses.

In this thesis, the role of vitamin D in obesity and other associated condi-tions has been studied.

In paper 1, the prevalence of vitamin D deficiency and secondary hyperpara-thyroidism over the long term after Roux-en-Y gastric bypass (RYGB) were evaluated. We found a substantial prevalence of vitamin D deficiency and secondary hyperparathyroidism after RYGB, whereas calcium levels remained within normal range. An expected improvement in vitamin D status after weight loss could have been countered by the malabsorption induced by surgery.

In paper 2, the prevalence of anemia and related deficiencies over the long term after RYGB were studied. We found that 27% of the patients had anemia postoperatively, 20% had iron deficiency, 12% had folate deficiency and 2% had vitamin B12 deficiency. Anemia was mainly due to iron deficiency, and its frequency did not seem to progress with time after surgery.

In paper 3, the effects of vitamin D supplementation on body composition and cardiorespiratory fitness in overweight men with vitamin D deficiency at baseline were investigated. No statistically significant difference between the placebo and the intervention group regarding changes in percentage body fat, maximum oxygen uptake, BMI and maximum load was found.

In paper 4, the prevalence and determinants of 3-epi-25(OH)D3 were exam-ined. 3-epi-25(OH)D3 was detected in 7.7% of the study population and the mean concentration was 8.4 nmol/L. The quantification of 3-epi-25(OH)D3 would not significantly influence the clinical interpretation of vitamin D levels.

In conclusion, new knowledge about vitamin D is continuously emerging but there is a discrepancy between cross-sectional studies associating low vitamin D levels to obesity and other related metabolic complications and the lack of effects of vitamin D supplementation in clinical trials. Large RCTs with longer duration in obese subjects with baseline vitamin D deficiency are warranted.

Ort, förlag, år, upplaga, sidor
Örebro: Örebro University , 2018. , s. 67
Serie
Örebro Studies in Medicine, ISSN 1652-4063 ; 177
Nyckelord [en]
Vitamin D, obesity, Roux-en-Y gastric bypass, secondary hyperpara-thyroidism, anemia, iron deficiency, body composition, cardiorespiratory fitness, Vitamin D C3 epimer
Nationell ämneskategori
Allmänmedicin
Identifikatorer
URN: urn:nbn:se:oru:diva-64979ISBN: 978-91-7529-238-0 (tryckt)OAI: oai:DiVA.org:oru-64979DiVA, id: diva2:1181962
Disputation
2018-04-20, Örebro universitet, Campus USÖ, hörsal C3, Södra Grev Rosengatan 32, Örebro, 13:00 (Svenska)
Opponent
Handledare
Tillgänglig från: 2018-02-12 Skapad: 2018-02-12 Senast uppdaterad: 2019-02-06Bibliografiskt granskad
Delarbeten
1. Vitamin D Status 10 Years After Primary Gastric Bypass: Gravely High Prevalence of Hypovitaminosis D and Raised PTH Levels
Öppna denna publikation i ny flik eller fönster >>Vitamin D Status 10 Years After Primary Gastric Bypass: Gravely High Prevalence of Hypovitaminosis D and Raised PTH Levels
Visa övriga...
2014 (Engelska)Ingår i: Obesity Surgery, ISSN 0960-8923, E-ISSN 1708-0428, Vol. 24, nr 3, s. 343-348Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The primary aim of this study was to evaluate the prevalence of vitamin D deficiency and secondary hyperparathyroidism after Roux-en-Y gastric bypass. Secondly, we have tried to assess predictors for vitamin D deficiency. Five hundred thirty-seven patients who underwent primary Roux-en-Y gastric bypass surgery between 1993 and 2003 at the A-rebro University Hospital and Uppsala University Hospital were eligible for the study. Patients were asked to provide a blood sample between November 2009 and June 2010 and to complete a questionnaire about their postoperative health status. Serum values of 25-OH vitamin D, parathyroid hormone (PTH), alkaline phosphatase (ALP) and calcium were determined. Follow-up was completed in 293 patients, of which 83 % were female, with an age of 49 +/- 9.9 years after a median time of 11 +/- 2.8 years. Vitamin D, PTH and albumin-corrected calcium values were 42 +/- 20.4 nmol/L, 89.1 +/- 52.7 ng/L and 2.3 +/- 0.1 mmol/L, respectively. Of all patients, 65 % were vitamin D deficient, i.e. 25-OH vitamin D < 50 nmol/L, and 69 % had PTH above the upper normal reference range, i.e. > 73 ng/L. Vitamin D was inversely correlated with PTH levels (p < 0.001) and positively correlated with calcium (p = 0.016). Vitamin D did not correlate with ALP. The only factor found to predict vitamin D deficiency was high preoperative body mass index (BMI) (p = 0.008), whereas gender, age, time after surgery and BMI at follow-up did not. Vitamin D deficiency and secondary hyperparathyroidism after Roux-en-Y gastric bypass (RYGB) were confirmed in our study because 65 % of patients had vitamin D deficiency, and 69 % had increased PTH levels more than 10 years after surgery. These data are alarming and highlight the need for improved long-term follow-up. Vitamin D deficiency does not seem to progress with time after surgery, possibly due to weight loss. Only preoperative BMI, cutoff point 43 kg/m(2), was a predictor of vitamin D deficiency at follow-up. Improved long-term follow-up of patients that undergo RYGB is needed.

Nyckelord
Vitamin D, Gastric bypass, Hyperparathyroidism, Long-term follow-up
Nationell ämneskategori
Kirurgi
Identifikatorer
urn:nbn:se:oru:diva-56581 (URN)10.1007/s11695-013-1104-y (DOI)000330983200001 ()24163201 (PubMedID)
Tillgänglig från: 2017-03-20 Skapad: 2017-03-20 Senast uppdaterad: 2019-02-06Bibliografiskt granskad
2. Prevalence of anemia and related deficiencies 10 years after gastric bypass: a retrospective study
Öppna denna publikation i ny flik eller fönster >>Prevalence of anemia and related deficiencies 10 years after gastric bypass: a retrospective study
Visa övriga...
2015 (Engelska)Ingår i: Obesity Surgery, ISSN 0960-8923, E-ISSN 1708-0428, Vol. 25, nr 6, s. 1019-1023Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Bariatric surgery has gained wide acceptance as treatment for severe obesity and is associated with decreased overall mortality. The aims of this study were to evaluate the prevalence of anemia long term after Roux-en-Y gastric bypass (RYGB) and to search for factors predicting anemia.

All 745 patients who underwent RYGB between 1993 and 2003 at either A-rebro or Uppsala University Hospital and who were living in Sweden were invited to participate by providing a fasting blood sample and completing a questionnaire about their health status. Full blood count, serum iron, transferrin, vitamin B-12, and folic acid were determined.

Follow-up was completed in 431 patients (58 %) with mean age 51.3 +/- 10 years. Of all patients, 27 % had anemia postoperatively and related deficiencies; iron, folic acid, and vitamin B-12 were seen in 20, 12, and 2 %, respectively. There was no correlation between anemia and sex, follow-up time, 25-OH vitamin D level, and preoperative or postoperative BMI. An inverse correlation was found between anemia and regular medical checkups concerning gastric bypass surgery.

Twenty-seven percent of patients had anemia more than 10 years after RYGB. Anemia does not seem to progress with time and was less common in patients with regular medical checkups. Thus, improved long-term follow-up is needed.

Ort, förlag, år, upplaga, sidor
Springer, 2015
Nyckelord
Gastric bypass, Anemia, Iron deficiency, Long-termfollow-up
Nationell ämneskategori
Kirurgi
Forskningsämne
Kirurgi
Identifikatorer
urn:nbn:se:oru:diva-44899 (URN)10.1007/s11695-014-1500-y (DOI)000354216500010 ()25394588 (PubMedID)2-s2.0-84939978711 (Scopus ID)
Anmärkning

Funding Agencies:

Örebro County Council

Uppsala-Örebro Regional Research Council RFR-32261

Tillgänglig från: 2015-06-15 Skapad: 2015-06-15 Senast uppdaterad: 2018-04-16Bibliografiskt granskad
3. Vitamin D C3 epimer in a mid-Swedish region: Analytical measurement and epidemiology
Öppna denna publikation i ny flik eller fönster >>Vitamin D C3 epimer in a mid-Swedish region: Analytical measurement and epidemiology
Visa övriga...
2018 (Engelska)Ingår i: Clinica Chimica Acta, ISSN 0009-8981, E-ISSN 1873-3492, Vol. 478, s. 182-187Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Background: The discovery of an epimeric form of 25(OH)D3 may complicate the interpretation of vitamin Dstatus. The aim of this study was to examine the prevalence and determinants of 25-hydroxy-3-epi-vitamin D3 (3- epi-25(OH)D3) in a mid-Swedish region and to investigate how the measurement of 3-epi-25(OH)D3 would affect the assessment of vitamin D status using current thresholds.

Methods: We conducted a cross-sectional study of 8286 in- and outpatients in primary as well as secondary care settings. Plasma 25(OH)D, 25(OH)D2, 25(OH)D3 and 3-epi-25(OH)D3 were measured using High Pressure Liquid Chromatography – Tandem Mass Spectrometry (HPLC – MS/MS). The relative 3-epi-25(OH)D3 contribution was calculated as a percentage of the total 25(OH)D3. Blood samples were collected between March 2014 and July 2015 providing a seasonal aspect to the results.

Results: 3-epi-25(OH)D3was detected in 635 cases (7.7% of all subjects), and the mean concentration was8.4 ± 3.5 nmol/L. 3-epi-25(OH)D3correlated significantly with 25(OH)D3(r =0.38, p < 0.001).A multivariateanalysis among the detected showed that male gender and winter season were independently associatedwith higher 3-epi-25(OH)D3/25(OH)D3percentage ratio (R2=0.044). Infants and children had a significantlyhigher detection rate compared to the reference age category (18–45 years) as well as those who were testedduring the summer season.

Conclusions: We report findings from the first epidemiologic study of 3-epi-25(OH)D3 conducted in Sweden, based on a large population sample. 3-epi-25(OH)D3 was detected in 7.7% of the study population and the mean concentration was 8.4 nmol/L. The quantification of 3-epi-25(OH)D3 would not significantly influence the clinical interpretation of vitamin D levels. Additional studies are needed to understand the metabolic pathway and the possible physiological functions of this metabolite.

Ort, förlag, år, upplaga, sidor
Amsterdam, Netherlands: Elsevier, 2018
Nyckelord
3-epi 25(OH)D(3), 25(OH)D(3), High Pressure Liquid Chromatography – Tandem Mass Spectrometry (HPLC – MS/MS), Vitamin D
Nationell ämneskategori
Biomedicinsk laboratorievetenskap/teknologi
Identifikatorer
urn:nbn:se:oru:diva-64072 (URN)10.1016/j.cca.2018.01.002 (DOI)000425070000028 ()29305842 (PubMedID)
Anmärkning

Funding Agency:

Örebro University  ALF 2016:1 OLL-615521

Tillgänglig från: 2018-01-12 Skapad: 2018-01-12 Senast uppdaterad: 2019-02-06Bibliografiskt granskad
4. Effect of Vitamin D supplementation on body composition and cardiorespiratory fitness in overweight men: A randomized controlled trial
Öppna denna publikation i ny flik eller fönster >>Effect of Vitamin D supplementation on body composition and cardiorespiratory fitness in overweight men: A randomized controlled trial
Visa övriga...
(Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Nationell ämneskategori
Allmänmedicin
Identifikatorer
urn:nbn:se:oru:diva-66214 (URN)
Tillgänglig från: 2018-03-28 Skapad: 2018-03-28 Senast uppdaterad: 2019-03-26Bibliografiskt granskad

Open Access i DiVA

Cover(112 kB)20 nedladdningar
Filinformation
Filnamn COVER01.pdfFilstorlek 112 kBChecksumma SHA-512
e5203013069c3167c57fa0c9028324ba26411ae631e46b6974e6f64673602a68d5b83d237c2e2358ff0865b37bfaf79c3843aeeb63f812364d33b88fbb0e6d42
Typ coverMimetyp application/pdf
Spikblad(65 kB)16 nedladdningar
Filinformation
Filnamn SPIKBLAD01.pdfFilstorlek 65 kBChecksumma SHA-512
f791d57a582b8a884e28b7e04bd28043e037195999f9ea24a92cec20fe9bc9166e1474e2833ce8d5574bef352ee4b9b96b6a4759fd1f6a2660e7dca6d3eec57b
Typ spikbladMimetyp application/pdf

Personposter BETA

Karefylakis, Christos

Sök vidare i DiVA

Av författaren/redaktören
Karefylakis, Christos
Av organisationen
Institutionen för medicinska vetenskaper
Allmänmedicin

Sök vidare utanför DiVA

GoogleGoogle Scholar
Antalet nedladdningar är summan av nedladdningar för alla fulltexter. Det kan inkludera t.ex tidigare versioner som nu inte längre är tillgängliga.

isbn
urn-nbn

Altmetricpoäng

isbn
urn-nbn
Totalt: 416 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf