title: Vitamin D Status during Pregnancy in a Multi-Ethnic Population-Representative Swedish Cohort.
abstract: There is currently little information on changes in vitamin D status during pregnancy and its predictors. The aim was to study the determinants of change in vitamin D status during pregnancy and of vitamin D deficiency (<30 nmol/L) in early pregnancy. Blood was drawn in the first (T1) and third trimester (T3). Serum 25-hydroxyvitamin D (25(OH)D) (N= 1985) was analysed by liquid chromatography tandem-mass spectrometry. Season-corrected 25(OH)D was calculated by fitting cosine functions to the data. Mean (standard deviation) 25(OH)D was 64.5(24.5) nmol/L at T1 and 74.6(34.4) at T3. Mean age was 31.3(4.9) years, mean body mass index (BMI) was 24.5(4.2) kg/m² and 74% of the women were born in Sweden. Vitamin D deficiency was common among women born in Africa (51%) and Asia (46%) and prevalent in 10% of the whole cohort. Determinants of vitamin D deficiency at T1 were of non-North European origin, and had less sun exposure, lower vitamin D intake and lower age. Season-corrected 25(OH)D increased by 11(23) nmol/L from T1 to T3. The determinants of season-corrected change in 25(OH)D were origin, sun-seeking behaviour, clothing style, dietary vitamin D intake, vitamin D supplementation and recent travel <35° N. In conclusion, season-corrected 25(OH)D concentration increased during pregnancy and depended partly on lifestyle factors. The overall prevalence of vitamin D deficiency was low but common among women born in Africa and Asia. Among them, the determinants of both vitamin D deficiency and change in season-corrected vitamin D status were fewer, indicating a smaller effect of sun exposure.
authors: Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden. linnea.barebring@gu.se.
authors: Linnea
authors: L
authors: Bärebring
authors: Medical Research Council Human Nutrition Research, CB19NL Cambridge, UK. I.Schoenmakers@uea.ac.uk.|Department of Medicine, Faculty of Medicine and Health Science, University of East Anglia, NR47TJ Norwich, UK. I.Schoenmakers@uea.ac.uk.
authors: Inez
authors: I
authors: Schoenmakers
authors: Antenatal Care, Närhälsan Primary Care, 41118 Gothenburg, Sweden. anna.glantz@vgregion.se.
authors: Anna
authors: A
authors: Glantz
authors: Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden. lena.hulthen@medfak.gu.se.
authors: Lena
authors: L
authors: Hulthén
authors: Antenatal Care, Närhälsan Primary Care, 41118 Gothenburg, Sweden. ase.jagner@vgregion.se.
authors: Åse
authors: Å
authors: Jagner
authors: Antenatal Care, Närhälsan Primary Care, Södra Bohuslän, 41119 Gothenburg, Sweden. joy.ellis@vgregion.se.
authors: Joy
authors: J
authors: Ellis
authors: Gothenburg Technical Institute, 41125 Gothenburg, Sweden. mattias.barebring@gti.se.
authors: Mattias
authors: M
authors: Bärebring
authors: Södra Älvsborgs Hospital, Department of Obstetrics and Gynaecology, 50182 Boras, Sweden. maria.bullarbo@vgregion.se.|Department of Obstetrics and Gynaecology, Sahlgrenska Academy, University of Gothenburg, 41684 Gothenburg, Sweden. maria.bullarbo@vgregion.se.
authors: Maria
authors: M
authors: Bullarbo
authors: Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden. hanna.augustin@gu.se.
authors: Hanna
authors: H
authors: Augustin
mesh_terms: D000328:Adult; D044466:Asian People / Q000208:ethnology; D044383:Black People / Q000208:ethnology; D005260:Female; D006801:Humans; D008019:Life Style; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology / Q000208:ethnology*; D011261:Pregnancy Trimester, First / Q000097:blood*; D011263:Pregnancy Trimester, Third / Q000097:blood*; D015995:Prevalence; D012621:Seasons; D013472:Sunlight; D013548:Sweden / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000208:ethnology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Sweden; pregnancy; vitamin D deficiency; vitamin D status