title: Low vitamin D levels have become less common in primary hyperparathyroidism.
abstract: We compared temporal trends in serum 25-hydroxyvitamin D and parathyroid hormone (PTH) in two primary hyperparathyroidism (PHPT) cohorts recruited 20 years apart. The prevalence of 25-hydroxyvitamin D levels <20 and <30 ng/mL declined by 30-50 %, respectively, and was accompanied by lower PTH. In the older cohort, higher PTH may be due to lower 25-hydroxyvitamin D.
  
  
  BACKGROUND
  Vitamin D deficiency may exacerbate PHPT. Whether there have been temporal trends in 25-hydroxyvitamin D (25OHD) levels in PHPT is unclear. The prevalence of low vitamin D levels (25OHD <20 and <30 ng/mL) and associated biochemical and bone mineral density (BMD) profiles were assessed in two PHPT cohorts recruited over 20 years apart.
  
  
  METHODS
  This is a cross-sectional comparison of serum 25OHD levels, calciotropic hormones, and BMD between two PHPT cohorts recruited at the same hospital: the "old" (N = 103) and "new" (N = 100) cohorts were enrolled between 1984 and 1991 and between 2010 and 2014, respectively.
  
  
  RESULTS
  Mean 25OHD levels were 26 % higher in the new cohort (23 ± 10 vs. 29 ± 10 ng/mL, p < 0.0001). Levels of 25OHD <20 and <30 ng/mL declined from 46 and 82 %, respectively, to 19 and 54 % (both p < 0.0001). Supplemental vitamin D use was common in the new (64 %) but not the old cohort (0 %). The new cohort demonstrated 33 % lower serum PTH levels (p < 0.0001). Neither serum nor urine calcium differed. BMD was higher in the new cohort at all skeletal sites (all p < 0.001).
  
  
  CONCLUSIONS
  With the rise in vitamin D supplementation over the last two decades, low 25OHD levels are no longer common in PHPT patients in the New York area. Those with 25OHD <20 and <30 ng/mL have declined by over 50 and 30 %, respectively. The lower mean PTH levels in the new cohort are most likely accounted for by higher vitamin D intake. Whether improved vitamin D status also underlies the relatively higher BMD in the more vitamin D replete cohort of PHPT patients is unknown.
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH 8 West - 864, New York, NY, 10032, USA. mad2037@columbia.edu.
authors.forename: M D
authors.initials: MD
authors.lastname: Walker
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH 8 West - 864, New York, NY, 10032, USA.
authors.forename: E
authors.initials: E
authors.lastname: Cong
authors.affiliation: Department of Surgery, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Lee
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH 8 West - 864, New York, NY, 10032, USA.
authors.forename: A
authors.initials: A
authors.lastname: Kepley
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH 8 West - 864, New York, NY, 10032, USA.
authors.forename: C
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH 8 West - 864, New York, NY, 10032, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: McMahon
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH 8 West - 864, New York, NY, 10032, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Bilezikian
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH 8 West - 864, New York, NY, 10032, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Silverberg
mesh_terms: D000328:Adult; D000368:Aged; D015519:Bone Density / Q000502:physiology; D003430:Cross-Sectional Studies; D004363:Drug Utilization / Q000639:trends; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D010281:Parathyroid Hormone / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Prevalence; Primary hyperparathyroidism; Vitamin D deficiency