title: Maternal Vitamin D Status and Its Related Factors in Pregnant Women in Bangkok, Thailand.
abstract: BACKGROUND
  There are few data focusing on the prevalence of vitamin D deficiency in tropical countries.
  
  
  OBJECTIVE
  We determined the vitamin D status in pregnant women and examined the factors associated with vitamin D deficiency.
  
  
  METHODS
  A cross-sectional study of 147 pregnant Thai women aged 18-45 years at Siriraj Hospital (a university hospital in Bangkok, Thailand) was undertaken. Clinical data and plasma levels of 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone (iPTH), calcium, albumin, phosphate and magnesium were obtained in pregnant women at delivery.
  
  
  RESULTS
  The prevalence of hypovitaminosis D [defined as 25(OH)D <75 nmol/L] in pregnant women at delivery was 75.5% (95% confidence interval (CI), 67.7-82.2%). Of these, vitamin D insufficiency [defined as 25(OH)D 50-74.9 nmol/L] was found in 41.5% (95% CI, 33.4-49.9%) and vitamin D deficiency [25(OH)D <50 nmol/L] was found in 34.0% (95% CI, 26.4-42.3%) of women. The mean 25(OH)D concentration was 61.6 ± 19.3 nmol/L. The correlation between 25(OH)D and iPTH was weak (r = -0.29, P<0.01). Factors associated with vitamin D deficiency by multiple logistic regression were: pre-pregnancy body mass index (BMI in kg/m2, odds ratio (OR), 0.88, 95% CI 0.80-0.97, P = 0.01) and season of blood collection (winter vs. rainy, OR, 2.62, 95% CI 1.18-5.85, P = 0.02).
  
  
  CONCLUSIONS
  Vitamin D deficiency is common among pregnant Thai women. The prevalence of vitamin D deficiency increased in women who had a lower pre-pregnancy BMI and whose blood was collected in the winter. Vitamin D supplementation may need to be implemented as routine antenatal care.
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Busadee
authors.initials: B
authors.lastname: Pratumvinit
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Preechaya
authors.initials: P
authors.lastname: Wongkrajang
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Tuangsit
authors.initials: T
authors.lastname: Wataganara
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sithikan
authors.initials: S
authors.lastname: Hanyongyuth
authors.affiliation: Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Akarin
authors.initials: A
authors.lastname: Nimmannit
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Somruedee
authors.initials: S
authors.lastname: Chatsiricharoenkul
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Kotchamol
authors.initials: K
authors.lastname: Manonukul
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Kanit
authors.initials: K
authors.lastname: Reesukumal
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002118:Calcium / Q000097:blood; D002681:China / Q000208:ethnology; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008274:Magnesium / Q000097:blood; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D012621:Seasons; D012709:Serum Albumin / Q000032:analysis; D012959:Socioeconomic Factors; D013472:Sunlight; D013785:Thailand / Q000453:epidemiology; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates; D012709:Serum Albumin; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D008274:Magnesium; D002118:Calcium