What do systematic reviews say?

Vitamin A vs placebo

• Micronutrient supplementation in adults with HIV infection 2017 · Cochrane Headline outcomes only
  no estimate extracted
  3 studies · 495 participants
  Low

Vitamin D vs placebo

• Micronutrient supplementation in adults with HIV infection 2017 · Cochrane Headline outcomes only
  no estimate extracted
  4 studies · 299 participants
  Moderate

Summary of findings table ‐ Vitamin B12 supplementation vs no supplementation or placebo

It is very uncertain whether summary of findings table ‐ Vitamin B12 supplementation changes maternal vitamin B12 deficiency compared with placebo/no vitamin B12 supplementation (very low certainty).

• Vitamin B12 supplementation during pregnancy for maternal and child health outcomes 2024 · Cochrane Headline outcomes only
  RR 0.38 [0.28, 0.51]
  2 studies · 272 participants
  Very low

Vitamin D vs placebo or no intervention

Vitamin D showed no clear difference in cancer occurrence compared with placebo or no intervention (moderate certainty).

• Vitamin D supplementation for prevention of cancer in adults 2014 · Cochrane Headline outcomes only
  RR 1 [0.94, 1.06]
  18 studies · 50623 participants
  Moderate

Vitamin D vs placebo or no intervention

Vitamin D may leads to lower all‐cause mortality compared with placebo or no intervention (low certainty).

• Vitamin D supplementation for prevention of cancer in adults 2014 · Cochrane Headline outcomes only
  RR 0.93 [0.88, 0.98]
  15 studies · 49866 participants
  Low

Vitamin D vs placebo or no intervention

The review found no eligible studies for this question.

• Vitamin D supplementation for prevention of cancer in adults 2014 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin D vs placebo or no intervention

The review found no eligible studies for this question.

• Vitamin D supplementation for prevention of cancer in adults 2014 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin K antagonists vs placebo or no thromboprophylaxis

Vitamin K antagonists showed no clear difference in symptomatic VTE compared with placebo or no thromboprophylaxis (low certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 0.15 [0.02, 1.2]
  1 study · 311 participants
  Low

Vitamin K antagonists vs placebo or no thromboprophylaxis

Vitamin K antagonists showed no clear difference in major bleeding compared with placebo or no thromboprophylaxis (low certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 3.82 [0.97, 15.04]
  4 studies · 994 participants
  Low

Vitamin K antagonists vs placebo or no thromboprophylaxis

It is very uncertain whether vitamin K antagonists changes symptomatic PE compared with placebo or no thromboprophylaxis (very low certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 1.05 [0.07, 16.58]
  1 study · 311 participants
  Very low

Vitamin K antagonists vs placebo or no thromboprophylaxis

Vitamin K antagonists showed no clear difference in symptomatic DVT compared with placebo or no thromboprophylaxis (low certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 0.08 [0, 1.42]
  1 study · 311 participants
  Low

Vitamin K antagonists vs placebo or no thromboprophylaxis

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin K antagonists vs placebo or no thromboprophylaxis

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin K antagonists vs placebo or no thromboprophylaxis

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin K antagonists vs active control

Vitamin K antagonists showed no clear difference in symptomatic VTE compared with active control (moderate certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 1.5 [0.74, 3.04]
  1 study · 440 participants
  Moderate

Vitamin K antagonists vs active control

Vitamin K antagonists showed no clear difference in major bleeding compared with active control (low certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 0.14 [0.01, 2.75]
  1 study · 440 participants
  Low

Vitamin K antagonists vs active control

Vitamin K antagonists showed no clear difference in symptomatic PE compared with active control (moderate certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 1 [0.25, 3.95]
  1 study · 440 participants
  Moderate

Vitamin K antagonists vs active control

Vitamin K antagonists showed no clear difference in symptomatic DVT compared with active control (moderate certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 1.75 [0.75, 4.09]
  1 study · 440 participants
  Moderate

Vitamin K antagonists vs active control

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin K antagonists vs active control

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found