Table 3.
General characteristics of non-overlapping meta-analyses of randomised controlled trials of vitamin D supplementation for cardiovascular, metabolic, neonatal/infant/child related, pregnancy related, and other outcomes
| Outcome | Population | Type of metric (summary effect) | Units | MA model | No of studies in each MA | Reported summary effect (95% CI) | P value |
|---|---|---|---|---|---|---|---|
| Cardiovascular outcomes | |||||||
| Cardiovascular disease | General | RR | NA | Fixed | 2 | 0.95 (0.86 to 1.05) | 0.32 |
| Diastolic blood pressure | Normotensive or hypertensive | WMD | mm Hg | No info | 3 | −0.03 (−1.98 to 1.92) | 0.98 |
| Systolic blood pressure | Normotensive or hypertensive | WMD | mm Hg | No info | 3 | −2.39 (−5.7 to 0.9) | 0.16 |
| Metabolic disorders | |||||||
| Fasting glucose | Diabetes patients with normal glucose tolerance | WMD | nmol/L | No info | No info | 0.01 (−0.21 to 0.23) | 0.94 |
| Fasting glucose | Diabetes patients with abnormal glucose tolerance | WMD | nmol/L | No info | No info | −0.3 (−0.9 to 0.3) | 0.33 |
| High density lipoprotein | General | WMD | mg/dL | Fixed | 8 | −0.14 (−0.99 to 0.71) | 0.76 |
| Insulin resistance | Diabetes | SMD | NA | No info | 5 | 0.16 (−0.11 to 0.42) | 0.24 |
| Total cholesterol | General | WMD | mg/dL | Fixed | 11 | 1.52 (−1.42 to 4.46) | 0.32 |
| Low density lipoprotein | General | WMD | mg/dL | Fixed | 7 | 3.23 (0.55 to 5.9) | 0.02 |
| Triglycerides | General | WMD | mg/dL | Fixed | 8 | −1.92 (−7.72 to 3.88) | 0.53 |
| Neonatal/infant/child related outcomes | |||||||
| Birth length | Pregnant women | WMD | cm | Random | 2 | 0.97 (−0.41 to 2.34) | 0.17 |
| Low birth weight | Pregnant women | RR | NA | Fixed | 3 | 0.4 (0.23 to 0.71) | 0.001 |
| Dental caries | Children | RR | NA | Random | 38 | 0.53 (0.43 to 0.65) | 3.7×10−9 |
| Head circumference at birth | Pregnant women | WMD | cm | Random | 2 | 0.43 (0.06 to 0.79) | 0.02 |
| Small for gestational age | Pregnant women | RR | NA | Fixed | 2 | 0.67 (0.40 to 1.11) | 0.12 |
| Pregnancy related outcomes | |||||||
| Maternal vitamin D concentrations at term | Pregnant women | WMD | nmol/L | Random | 4 | 47.08 (23.76 to 70.39) | 8.7×10−5 |
| Mean gestational age at delivery | Pregnant women | WMD | Weeks | Fixed | 2 | 0.17 (-0.16 to 0.51) | 0.32 |
| Preterm delivery | Pregnant women | RR | NA | Fixed | 2 | 0.77 (0.35 to 1.66) | 0.52 |
| Other outcomes | |||||||
| Alkaline phosphatase | CKD NRD | WMD | U/L | Fixed | 2 | −21.81 (−40.39 to 3.22) | 0.06 |
| Alkaline phosphatase | CKD RD | WMD | U/L | Fixed | 3 | −27.35 (−50.69 to −4.01) | 0.02 |
| Creatinine clearance | CKD NRD | WMD | mL/min | Fixed | 4 | −1.68 (−6.92 to 3.56) | 0.54 |
| Mortality | General (vitamin D3) | RR | NA | Random | 9 | 0.91 (0.82 to 1.02) | 0.09 |
| Mortality | General (vitamin D2) | RR | NA | Random | 8 | 1.04 (0.97 to 1.11) | 0.26 |
| Mortality | CKD NRD | RR | NA | Fixed | 4 | 1.40 (0.38 to 5.15) | 0.63 |
| Mortality | CKD RD | RR | NA | Fixed | 5 | 1.34 (0.34 to 5.24) | 0.69 |
| Parathyroid hormone | CKD NRD | WMD | pmol/L | Fixed | 4 | −49.34 (−85.70 to −12.97) | 0.008 |
| Parathyroid hormone | CKD RD | WMD | pmol/L | Fixed | 6 | −196.05 (−298.43 to −93.66) | 0.0002 |
| Parathyroidectomy | CKD RD | RR | NA | Fixed | 2 | 0.82 (0.05 to 12.47) | 0.90 |
| Risk of hypercalcaemia | CKD NRD | RR | NA | Fixed | 7 | 3.04 (1.17 to 7.90) | 0.02 |
| Risk of hypercalcaemia | CKD RD | RR | NA | Fixed | 5 | 3.80 (0.90 to 16.12) | 0.07 |
| Risk of hyperphosphataemia | CKD NRD | RR | NA | Fixed | 2 | 1.58 (0.47 to 5.30) | 0.47 |
| Risk of hyperphosphataemia | CKD RD | RR | NA | Fixed | 2 | 1.57 (0.97 to 2.54) | 0.07 |
| Risk of requiring dialysis | CKD NRD | RR | NA | Fixed | 4 | 0.76 (0.36 to 1.62) | 0.48 |
| Subperiosteal erosions | CKD RD | RR | NA | Fixed | 3 | 0.41 (0.07 to 2.38) | 0.33 |
| Vascular calcification | CKD RD | RR | NA | Fixed | 2 | 1.09 (0.45 to 2.67) | 0.86 |
CKD NRD=chronic kidney disease not requiring dialysis; CKD RD=chronic kidney disease requiring dialysis; RR=relative risk; SMD=standardised mean difference; WMD=weighted mean difference.
P values were estimated using formulas presented in Altman and Bland 2011.140