Original Article
Vitamin D insufficiency is prevalent and vitamin D is inversely associated with parathyroid hormone and calcitriol in pregnant adolescents
Article first published online: 22 DEC 2011
DOI: 10.1002/jbmr.526
Copyright © 2012 American Society for Bone and Mineral Research
Additional Information
How to Cite
Young, B. E., McNanley, T. J., Cooper, E. M., McIntyre, A. W., Witter, F., Harris, Z. L. and O'Brien, K. O. (2012), Vitamin D insufficiency is prevalent and vitamin D is inversely associated with parathyroid hormone and calcitriol in pregnant adolescents. J Bone Miner Res, 27: 177–186. doi: 10.1002/jbmr.526
Publication History
- Issue published online: 22 DEC 2011
- Article first published online: 22 DEC 2011
- Accepted manuscript online: 28 SEP 2011 09:47AM EST
- Manuscript Accepted: 22 SEP 2011
- Manuscript Revised: 28 AUG 2011
- Manuscript Received: 29 MAY 2011
- Abstract
- Article
- References
- Cited By
Keywords:
- 25-HYDROXYVITAMIN D;
- 1,25-DIHYDROXYVITAMIN D;
- PARATHYROID HORMONE;
- PREGNANCY;
- ADOLESCENCE
Abstract
Few large studies have assessed changes in calcitropic hormones and maternal 25-hydroxyvitamin D (25(OH)D) status across pregnancy, and how this may impact maternal bone turnover and neonatal hormone status. We aimed to identify determinants of 25(OH)D, parathyroid hormone (PTH), and calcitriol across pregnancy in a longitudinal study of 168 pregnant adolescents (≤18 years of age). Maternal 25(OH)D, PTH, and calcitriol were assessed at mid-gestation (∼26 weeks), delivery, and in cord blood. Data were related to measures of maternal anthropometrics, dietary intake, physical activity, and bone turnover markers. Approximately 50% of teens and their infants had serum 25(OH)D ≤ 20 ng/mL; 25(OH)D was lower in African Americans versus whites (p < 0.001). PTH increased across gestation (p < 0.001). Elevated PTH (≥60 pg/mL) was detected in 25% of adolescents at delivery, and was associated with increased concentrations of serum N-telopeptide (NTX) (p = 0.028). PTH and calcitriol did not significantly differ across the range of Ca intake consumed (257–3220 mg/d). In the group as a whole, PTH was inversely associated with 25(OH)D in maternal circulation at mid-gestation (p = 0.023) and at delivery (p = 0.019). However, when the cohort was partitioned by 25(OH)D status, this relationship was only present in those with 25(OH)D ≤ 20 ng/mL, suggestive of a threshold below which 25(OH)D impacts PTH during pregnancy. Mid-gestation 25(OH)D was inversely associated with calcitriol at delivery (p = 0.023), irrespective of Ca intake. Neonatal PTH and calcitriol were significantly lower than (p < 0.001), but unrelated to maternal concentrations. These findings indicate that maternal 25(OH)D status plays a role in calcitropic hormone regulation in pregnant adolescents. © 2012 American Society for Bone and Mineral Research

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