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Table 4 Baseline and end-point mean 25(OH)D concentrations in vitamin D and placebo

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

ReferenceLatitudeVitamin D Daily Dosage (IU)WeeksVitamin D SupplementationaPlaceboa
NPrePostChangeNPrePostChange
Insufficient vitamin D (N = 92)         
Winter (N = 92)         
 Jung 2018 [30]< 45° N500042010.9 ± 0.538.4 ± 1.517.51512.4 ± 0.813.1 ± 1.00.7
 Close 2013b [32]≥45° N50006511.6 ± 10.041.3 ± 10.029.7521.2 ± 11.629.6 ± 9.68.4
bClose 2013a [28]≥45° N571412620.4 ± 10.436.5 ± 9.616.19^20.8 ± 10.816.4 ± 8.8−4.4
bClose 2013a [28]≥45° N2857121021.2 ± 10.434.1 ± 4.012.99^20.8 ± 10.816.4 ± 8.8− 4.4
 Wyon 2016 [29]≥45° N18,75011113.2 ± 3.816.8 ± 3.23.61116.3 ± 2.716.3 ± 2.60
Sufficient vitamin D (N = 57)         
Autumn (N = 57)         
 Fairbairn 2018 [31]≥45° S3570122837.2 ± 7.644.4 ± 7.27.22938 ± 6.834 ± 6.8−4
  1. aPresented in ng/mL. bClose et al. compared multiple doses with one control group. ^ Indicates findings are from one study