Determinants of Parathyroid Hormone Response to Vitamin D Supplementation: A Systematic Review and Meta-Analysis of Randomised Controlled Trials Publisher Pubmed



Moslehi N¹ ; Shabbidar S² ; Mirmiran P³ ; Hosseinpanah F⁴ ; Azizi F⁵ Show Affiliations
Source: British Journal of Nutrition Published:2015

Abstract

This systematic review aimed to assess the determinants of the parathyroid hormone (PTH) level response to vitamin D supplementation. We searched Medline, Google Scholar and the reference lists of previous reviews. All randomised controlled trials (RCT) on vitamin D supplementation that involved apparently healthy human subjects with a report of PTH were selected. Potential studies were screened independently and in duplicate. Results are summarised as mean differences with 95 % confidence intervals. Quality assessment, subgroup analysis, meta-analysis and meta-regression analysis were carried out. Thirty-three vitamin D supplementation RCT were included. Vitamin D supplementation significantly raised circulating 25-hydroxyvitamin D (25(OH)D) with significant heterogeneity among studies with a pooled mean difference (PMD) of 15.5 ng/ml (test for heterogeneity: P<0.001 and I 2=97.3 %). Vitamin D supplementation significantly reduced PTH level with PMD of-8.0 pg/ml, with significant heterogeneity ((test for heterogeneity: P<0.001) and the I 2 value was 97.3 %). In the subgroup analyses, the optimum treatment effect for PTH was observed with Ca doses of 600-1200 mg/d (-22.48 pg/ml), after the duration of a >12-month trial (-18.36 pg/ml), with low baseline 25(OH)D concentration of <20 ng/ml (-16.70 pg/ml) and in those who were overweight and obese (-18.11 pg/ml). Despite the present meta-analysis being hindered by some limitations, it provided some interesting evidence, suggesting that suppression of PTH level needs higher vitamin D intake (75 μg/d) than the current recommendations and longer durations (12 months), which should be taken into account for nutritional recommendations. © 2015 The Authors.