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Parathyroid Hormone in Pregnancy: Vitamin D and Other Determinants.

ABSTRACT: We aimed to assess the parathyroid hormone (PTH) concentration in pregnant women at the beginning of pregnancy (1st trimester) and within days before delivery (3rd trimester) and evaluate its determinants. From September 2014 through December 2015 in a cross-sectional study, 204 women in the 1st trimester of pregnancy and 203 women in the 3rd trimester of pregnancy were recruited. Blood samples were collected to measure PTH and circulating 25-hydroxy-vitamin D (25(OH)D) concentrations. Lifestyle and demographic data were collected using a questionnaire. Serum 25(OH)D and PTH were inversely correlated in both early and late pregnancy. Our analyses suggest that in the 3rd trimester of pregnancy, a 25(OH)D level of 18.9 ng/mL (47.3 nmol/L) could serve as an inflection point for the maximal suppression of PTH. Statistically significant determinants of PTH concentrations in multiple regression were 25(OH)D concentrations, season, multiparity and education of the partner (all p < 0.05) in early pregnancy. In late pregnancy, 25(OH)D concentrations and country of origin were statistically significant determinants of PTH concentrations (all p < 0.05). These factors and their effect on PTH appear to be vastly determined by 25(OH)D; however, they might also affect PTH through other mechanisms besides 25(OH)D.

SUBMITTER: Hysaj O

PROVIDER: S-EPMC7911996 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Parathyroid hormone in Sri Lankan pregnant women: Vitamin D and other determinants.

Project description:IntroductionDeterminants of parathyroid hormone level during pregnancy have been less frequently studied. We aimed to describe the serum parathyroid hormone (PTH) and its determinants in Sri Lankan pregnant women in a community setting.Materials and methodsIn this cross-sectional analysis, 390 pregnant mothers in their third trimester were enrolled from primary care centers of 15 health divisions in the Colombo District in Sri Lanka. Venous blood was analyzed for a total 25-hydroxyvitamin-D [25(OH)D], serum parathyroid hormone (PTH), serum calcium, and alkaline phosphatase. The bone quality was assessed in terms of speed of sound (SOS) using the quantitative ultrasound scan (QUS). Univariate and multivariate regression analysis was used to examine the determinants of PTH concentration in blood.ResultsMedian serum 25(OH)D was 17.5ng/mL. Most (61.6%) were vitamin D deficient (<20ng/mL). Median PTH was 23.7pg/mL. Only 0.8% had hyperparathyroidism (PTH >65pg/mL). The correlation between 25(OH)D and PTH was weak but significant (r = -0.197; p<0.001). SOS Z-score was below the cut-off (≤-2) in fifty-six women (14.7%), and SOS did not relate significantly to PTH. In regression analysis, serum 25(OH)D, serum calcium, body mass index, educational level, and weeks of pregnancy were significant independent variables when adjusted. The model explained 16% of the variation in the PTH level.ConclusionsA high prevalence of vitamin D deficiency was observed among Sri Lankan pregnant women in the present study. Serum 25(OH)D, calcium, weeks of pregnancy, and educational level were determinants of serum PTH.

| S-EPMC8500411 | biostudies-literature

Association of Vitamin D and Parathyroid Hormone With Barrett's Esophagus.

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Parathyroid hormone decreases renal vitamin D receptor expression in vivo.

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| S-EPMC555704 | biostudies-other

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Physiological regulation of phosphate by vitamin D, parathyroid hormone (PTH) and phosphate (Pi).

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Vitamin D, parathyroid hormone and cardiovascular risk: the good, the bad and the ugly.

Project description:: 25-Hydroxyvitamin D insufficiency and increased cardiovascular risk (CVR) association is still debated. The vitamin D (VitD)-dependent parathyroid hormone (PTH) is considered as the possible actuator of VitD effects on CVR. To investigate the association of CVR, PTH and VitD, we carried out blood pressure measurements and blood samples and collected information on dietary habits, anamnestic, clinical and metabolic data of 451 participants in the Salerno area (Southern Italy) during the World Hypertension Day (17 May). CVR was calculated according to the Framingham CVR charts. The overall population mean age was 51.6?±?0.7 years, and female sex was slightly prevalent (55%). VitD deficiency (<20?ng/ml) was most frequent (59.7%). In this population, VitD and CVR did not correlate. VitD and PTH inversely correlated (r?=?-0.265, P?<?0.001) as expected. PTH was in direct correlation (r?=?0.225, P?<?0.001) with CVR. Elevated PTH (75 percentile; ?49.5?pg/ml) levels identify a population with higher CVR (11.8?±?0.5 vs. 8.5?±?0.3, P?<?0.001). In a multivariate analysis, both age and PTH correlate to CVR, but not VitD. In conclusion, VitD does not directly affect CVR in the overall population. Rather, increased PTH might be a better predictor of CVR.

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Reduction of Parathyroid Hormone with Vitamin D Supplementation in Blacks: A Randomized Controlled Trial.

Project description:BACKGROUND:Response of parathyroid hormone (PTH) to vitamin D supplementation is determined by the baseline PTH level and change in vitamin D status. Conflicting reports in Blacks exist on the PTH response to vitamin D to supplementation. METHODS:During 3 winters from 2007-2010, 328 healthy Blacks (median age, 51 years) living in Boston, MA were randomized into a 4-arm, double-blind trial for 3 months of placebo, 1000, 2000, or 4000 IU of vitamin D3. PTH was measured in 254 participants at baseline and at the end of vitamin D supplementation period. RESULTS:The differences in PTH between baseline and 3 months were 3.93 pg/mL for those receiving placebo, -3.37 pg/mL for those receiving 1000 IU/d, -6.76 pg/mL for those receiving 2000 IU/d, and -8.99 pg/mL for those receiving 4000 IU/d ( -2.98 pg/mL for each additional 1000 IU/d of vitamin D3; p<0.001). CONCLUSION:We found a significant decrease in PTH with increasing doses of vitamin D supplementation up to intakes of 4000 IU/d in Blacks. Clinical Trials.gov: NCT00585637.

| S-EPMC4743037 | biostudies-literature