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Table 2 Baseline measurements of the included randomized controlled trials

From: Effects of vitamin D3 supplementation on serum 25(OH)D concentration and strength in athletes: a systematic review and meta-analysis of randomized controlled trials

ReferenceAnalyzed (n = 149)VD3 Daily Dosage IUMales (%)Mean Age Years25(OH)D (ng/mL)25(OH)D (nmol/L)25(OH)D Method of AnalysisLost to Follow-up
Jung 2018 [30]20500060% (21/35)20.1 ± 0.1510.9 ± 0.4727.3 ± 1.18CLIA analyzer (Liaison XL, Dasorin, Italy)9
15PL  12.36 ± 0.7830.9 ± 1.95(20.45%)
Fairbairn 2018 [31]28357010021.5 ± 2.837.2 ± 7.693 ± 19LC-MS/MS at Canterbury Health
Laboratories, Christchurch, New Zealand
0
29PL 20.9 ± 2.838 ± 6.895 ± 17 
Close 2013b [32]5500010018 ± 511.6 ± 1029 ± 25HPLC-MRM (Becton Dickinson, Oxford, UK)0
5PL  21.2 ± 11.653 ± 29 
Close 2013a [28]6571410021 ± 120.4 ± 10.451 ± 26HPLC-MRM (Becton Dickinson, Oxford, UK)5
102857 22 ± 221.2 ± 10.453 ± 26(16.70%)
9PL 21 ± 120.8 ± 10.852 ± 27 
Wyon 2016 [29]1118,75010029 ± 10.613.2 ± 3.832.8 ± 9.4ECLIA (Tecan Infinite F500, Mannedorf, Switzerland)0
11PL 26 ± 7.416.3 ± 2.740.7 ± 6.8 
  1. Data are mean ± standard deviation unless stated otherwise. CLIA Chemiluminescent immunoassay, ECLIA Electrochemiluminescent immunoassay, HPLC-MRM High-performance liquid chromatography tandem multiple reaction mode, HPLC-MS High-performance liquid chromatography-tandem mass spectrometry, LC–MS/MS Liquid chromatography mass spectrometry, PL Placebo. 2013a, 30 football and rugby athletes were recruited in reference 28; 2013b, 10 soccer players were recruited in reference [32]