Background
Methods
Literature search strategy
Selection criteria
Data extraction and management:
Author, year of publication | Country | Study design | Status | Sample size | Sex (% of women) | Mean age | Intervention | Supplemented the dose of vitamin D (IU/day) | Follow-up duration |
---|---|---|---|---|---|---|---|---|---|
A Sadiya (47), 2015 | UAE | randomized double-blind clinical trial | vitamin D-deficient obese, type 2 diabetic | 87 | Male and Female (70%) | 49 ± 8 | cholecalciferol (vitamin D3) | phase 1; 6000 phase 2; 3000 | 6 month |
A. Breslavsky (48), 2013 | Israel | randomized, placebo-controlled | type 2 diabetes mellitus | 47 | Male and Female (53.1%) | 66.8 ± 9.2 | cholecalciferol (vitamin D3) | 1000 | 12 month |
Claudia Gagnon [34], 2014 | Australia | randomized, placebo-controlled trial | vitamin D-deficient and at risk of type 2 diabetes | 95 | Male and Female (71%) | 54 years | cholecalciferol (vitamin D3) | 2000–6000 | 6 month |
Edgar Turner Overton [33], 2015 | USA | randomized, double-blind, placebo-controlled | HIV-infected | 167 | Male and Female (9%) | 36 years | cholecalciferol (vitamin D3) | 4000 | 48-week |
Gavin Dreyer [30], 2014 | UK | randomised controlled trial | non-diabetic chronic kidney disease stage 3–4 and concomitant vitamin D deficiency | 38 | Male and Female (39.1%) | 45.8 (10.0) | ergocalciferol | 50,000 | 6 month |
Indrani Sinha-Hikim [25], 2015 | USA | randomized | pre-diabetes and hypovitaminosis D | 80 | Male and Female (70%) | 52.0 years | cholecalciferol (vitamin D3) | 85,300 IU ± 16,000 | 12 month |
Isa Gabriela de Medeiros Cavalcante [29], 2015 | Brazil | double blind, randomized, placebo-controlled trial | With vitamin D insufficiency | 40 | Female (100%) | 68 ± 6 | cholecalciferol (vitamin D3) | 200,000 | 4 week |
Julia Åivo (49), 2015 | Finland | double-blind, randomized, parallel | 59 | Male and Female (62.7%) | 38 (22–53) | cholecalciferol (vitamin D3) | 20,000 | 12 month | |
L. Wamberg (50), 2013 | Denmark | double-blind design | 52 | Male and Female (71%) | 18 to 50 years | cholecalciferol (vitamin D3) | 7000 | ||
M.D. Witham (51), 2015 | UK | Parallel-group, double-blind, randomised placebo-controlled trial | with chronic fatigue syndrome | 50 | Male and Female (52%) | 49 ± 13 | cholecalciferol (vitamin D3) | 100,000 | 6 month |
M.P. BJORKMAN [28], 2009 | Finland | randomised double-blind placebo controlled trial | chronically impaired mobility | 218 | Male and Female | 84.5 ± 7.5 | cholecalciferol (vitamin D3) | 0 400 1200 | 6 month |
Nafiseh Toghianifar (52), 2015 | Iran | double blind randomized clinical trial | with a diagnosis of relapsing remitting multiple sclerosis (RRMS) | 94 | Male and Female (84.2%) | 31.50 ± 7.60 | cholecalciferol (vitamin D3) | 50,000 | 12 week |
Nasrin Sharifi (53), 2014 | Iran | parallel, double-blind, placebo-controlled | non-alcoholic fatty liver disease (NAFLD) | 53 | Male and Female (51%) | 40.33 ± 8.65 | cholecalciferol (vitamin D3) | 50,000 | 4 month |
Ohk-Hyun Ryu [32], 2014 | Korea | prospective, randomized, double-blinded, placebo-controlled trial | type 2 diabetic patients | 62 | Male and Female | 54.5 ± 7.4 | cholecalciferol (vitamin D3) | 2000 | 24 week |
Pamela R. von Hurst (54), 2010 | New Zealand | randomised, placebo-controlled trial | 81 | Female (100%) | 45.5 | cholecalciferol (vitamin D3) | 4000 | 6 month | |
Paulette D. Chandler (55), 2014 | USA | Randomized, Placebo-Controlled Trial | 328 | Male and Female (67.7%) | 51 | cholecalciferol (vitamin D3) | 1000 2000 4000 | 3 month | |
Rahaimi (56), 2013 | Iran | randomised, placebo-controlled, double-blinded trial | With vitamin D deficiency | 50 | Female (100%) | 30 | cholecalciferol (vitamin D3) | 50,000 | 2 month |
Rolf Jorde (57), 2010 | Norway | Randomized | overweight and obese | 437 | Male and Female (64.3%) | 47 | cholecalciferol (vitamin D3) | 40,000 | 12 month |
Seth I Sokol [31], 2012 | USA | double-blind placebo wait-list control design | with CAD and vitamin D deficiency | 90 | Male and Female (26.5%) | 55 ± 9.6 | ergocalciferol | 50,000 | 12 week |
Tina K. Thethi, 2015 | USA | double blind, randomized, placebo-controlled trial | with type 2 diabetes and chronic kidney disease | 55 | Male and Female (32.7%) | 63 | Paricalcitol | 1 mcg | 3 month |
Tyler Barker (58), 2015 | USA | randomized, double blind, placebo-controlled | 56 | Male and Female (32.7%) | 32(7) | cholecalciferol (vitamin D3) | 4000 8000 | 5 week | |
Ulla Kampmann (59), 2014 | Denmark | double-blind, randomized, placebo-controlled trial | with type 2 diabetes and hypovitaminosis D | 15 | Male and Female (46.6%) | 59.3 ± 4.4 | cholecalciferol (vitamin D3) | 5600 11,200 | 12 week |
Zatollah Asemi (60), 2013 | Iran | randomized, double-blind, placebo-controlled clinical | healthy pregnant women | 48 | Female (100%) | 29 | cholecalciferol (vitamin D3) | 400 | 25 week |
Quality assessment
Data preparation for meta-analysis:
Determining potential publication bias
Results
Selection RCTs
Risk of bias assessment
Characteristics of the studies
Pooled estimate of the impact of vitamin D supplementation on C-reactive protein
Pooled estimate of the effect of vitamin D supplementation on IL-6
Pooled estimate of the effect of vitamin D supplementation on IL-10
Pooled estimate of the effect of vitamin D supplementation on TNF-α
Pooled estimate of the effect of vitamin D supplementation on adiponectin
Pooled estimate of the effect of vitamin D supplementation on ICAM-1
Pooled estimate of the effect of vitamin D supplementation on IL-7
Pooled estimate of the effect of vitamin D supplementation on IL-2
Pooled estimate of the effect of vitamin D supplementation on IL-4
Pooled estimate of the effect of vitamin D supplementation on IL-5
Pooled estimate of the effect of vitamin D supplementation on IL-12
Pooled estimate of the effect of vitamin D supplementation on IL-13
Sensitivity analysis
Variables | Result of the leave-one-out sensitivity analyses |
---|---|
C-reactive protein | |
Across all studies | -0.26(mg/l), (95% CI -0.75 to 0.22) |
Interleukin-6 | |
Across all studies | 0.67(ng/dl), (95% CI 0.29 to 1.06,) |
Interleukin −10 | |
Across all studies | 0.43(ng/dl), (95% CI -0.56 to 1.44) |
TNF-α | |
Across all studies | −0.11(ng/dl), (95% CI -0.53 to 0.30) |
Adiponectin | |
Across all studies | 4.03 (pg/ml), (95% CI 3.50 to 4.57) |
ICAM-1 | |
Across all studies | −0.79 (pg/ml), (95% CI 1.33 to 0.26) |
IL-7 | |
Across all studies | −2.32 (pg/ml), (95% CI -4.32 to −0.31) |
IL-2 | |
Across all studies | −0.111 (pg/ml), (95% CI -1.27 to 1.07) |
IL-4 | |
Across all studies | 0.027 (pg/ml), (95% CI -0.72 to 0.77) |
IL-5 | |
Across all studies | 0.631 (pg/ml), (95% CI -0.05 to 1.32) |
IL-12 | |
Across all studies | 0.045 (pg/ml), (95% CI -0.14 to 0.23) |
IL-13 | |
Across all studies | −0.15 (pg/ml), (95% CI -0.78 to 0.48) |
N=Number |