title: Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women.
abstract: OBJECTIVE
  To examine vitamin D status and parathyroid function in normal Danish women postpartum.
  
  
  METHODS
  Three cross-sectional measures during follow-up of 89 women postpartum.
  
  
  METHODS
  We assessed vitamin D status by measuring plasma 25-hydroxyvitamin D (P-25OHD) and the degree of secondary hyperparathyroidism by measuring plasma parathyroid hormone (P-PTH) in 89 Caucasian women at three consecutive visits: (mean (range)) 23 (10-37) days (spring), 117 (95-140) days (late summer) and 274 (254-323) days (winter) postpartum.
  
  
  RESULTS
  P-25OHD showed seasonal variations with higher values in late summer than in the other periods (P < 0.001). At the first visit, 65% received vitamin D supplements. At the following visits, almost 50% were supplemented. Vitamin D insufficiency (P-25OHD < 50 nmol/l) occurred more often during winter (28%) than in spring (14%) (Fisher's exact test, P = 0.02) or late summer (7%) (P = 0.0001). Irrespective of season, vitamin D insufficiency occurred most frequent in women who did not take vitamin D supplements (Fisher's exact test, P < 0.02). Frank vitamin D deficiency (P-25OHD < 25 nmol/l) was observed during winter in 6%. At all three periods, P-25OHD correlated inversely with P-PTH indicating secondary hyperparathyroidism at deficient vitamin D status. During spring, late summer and winter three, one and four females, respectively, had elevated plasma PTH.
  
  
  CONCLUSIONS
  Vitamin D insufficiency with secondary hyperparathyroidism is a frequent finding in healthy Danish women postpartum and especially during winter. Vitamin D supplements reduced the risk of vitamin D insufficiency, especially during winter. Our results support the importance of increased alertness regarding information of pregnant and lactating women about vitamin D supplements. Furthermore, it has to be studied whether the present recommendations of an intake of 5-10 microg vitamin D/day are sufficient, especially during winter months.
authors.affiliation: Department of Endocrinology and Metabolism C, Aarhus University Hospital, Aarhus, Denmark. Kristine.moller@ki.au.dk
authors.forename: U K
authors.initials: UK
authors.lastname: Møller
authors.forename: C H
authors.initials: CH
authors.lastname: Ramlau-Hansen
authors.forename: L
authors.initials: L
authors.lastname: Rejnmark
authors.forename: L
authors.initials: L
authors.lastname: Heickendorff
authors.forename: T B
authors.initials: TB
authors.lastname: Henriksen
authors.forename: L
authors.initials: L
authors.lastname: Mosekilde
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology*; D009752:Nutritional Status; D010281:Parathyroid Hormone / Q000097:blood*; D049590:Postpartum Period; D012621:Seasons; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D