PLoS ONE (Jan 2015)

Temporal relationship between vitamin D status and parathyroid hormone in the United States.

  • Martin H Kroll,
  • Caixia Bi,
  • Carl C Garber,
  • Harvey W Kaufman,
  • Dungang Liu,
  • Anne Caston-Balderrama,
  • Ke Zhang,
  • Nigel Clarke,
  • Minge Xie,
  • Richard E Reitz,
  • Stephen C Suffin,
  • Michael F Holick

DOI
https://doi.org/10.1371/journal.pone.0118108
Journal volume & issue
Vol. 10, no. 3
p. e0118108

Abstract

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Interpretation of parathyroid hormone (iPTH) requires knowledge of vitamin D status that is influenced by season.Characterize the temporal relationship between 25-hydroxyvitamin D3 levels [25(OH)D3] and intact iPTH for several seasons, by gender and latitude in the U.S. and relate 25-hydrovitamin D2 [25(OH)D2] levels with PTH levels and total 25(OH)D levels.We retrospectively determined population weekly-mean concentrations of unpaired [25(OH)D2 and 25(OH)D3] and iPTH using 3.8 million laboratory results of adults. The 25(OH)D3 and iPTH distributions were normalized and the means fit with a sinusoidal function for both gender and latitudes: North >40, Central 32-40 and South 65 pg/mL). The percentage of patients deficient in 25(OH)D3 seasonally varied from 21% to 48% and the percentage with elevated iPTH reciprocally varied from 28% to 38%. Patients with detectable 25(OH)D2 had higher PTH levels and 57% of the samples with a total 25(OH)D > 50 ng/mL had detectable 25(OH)D2.25(OH)D3 and iPTH levels vary in a sinusoidal pattern throughout the year, even in vitamin D2 treated patients; 25(OH)D3, being higher in the summer and lower in the winter months, with iPTH showing the reverse pattern. A large percentage of the tested population showed vitamin D deficiency and secondary hyperparathyroidism. These observations held across three latitudinal regions, both genders, multiple-years, and in the presence or absence of detectable 25(OH)D2, and thus are applicable for patient care.