What do systematic reviews say?

Vitamin C vs placebo

• Vitamin C for asthma and exercise‐induced bronchoconstriction 2013 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 41 participants
  Very low

Vitamin C vs placebo

The review found no eligible studies for this question.

• Vitamin C for asthma and exercise‐induced bronchoconstriction 2013 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin C vs placebo

The review found no eligible studies for this question.

• Vitamin C for asthma and exercise‐induced bronchoconstriction 2013 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin C vs placebo

• Vitamin C for asthma and exercise‐induced bronchoconstriction 2013 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 8 participants
  Low

Vitamin C vs placebo

• Vitamin C for asthma and exercise‐induced bronchoconstriction 2013 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 8 participants
  Low

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 272 participants
  Moderate

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

Vitamin E (capsules 2000 IU/day in two divided doses) showed no clear difference in adverse events Number of participants reporting ≥ 1 serious adverse… compared with placebo (moderate certainty).

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  RR 0.86 [0.71, 1.05]
  1 study · 304 participants
  Moderate

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

Vitamin E (capsules 2000 IU/day in two divided doses) showed no clear difference in deaths Number of deaths compared with placebo (moderate certainty).

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  RR 0.84 [0.52, 1.34]
  1 study · 304 participants
  Moderate

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 280 participants
  Moderate

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

Vitamin E (capsules 2000 IU/day in two divided doses) showed no clear difference in progression to Alzheimer's disease Number of people progressing to AD compared with placebo (moderate certainty).

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  RR 1.03 [0.79, 1.35]
  1 study · 516 participants
  Moderate

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

The review found no eligible studies for this question.

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 516 participants
  GRADE not reported

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

Vitamin E (capsules 2000 IU/day in two divided doses) showed no clear difference in death Number of deaths over 36 months compared with placebo (moderate certainty).

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · Cochrane Headline outcomes only
  RR 1.01 [0.3, 3.44]
  1 study · 516 participants
  Moderate

Vitamin E (capsules 2000 IU/day in two divided doses) vs placebo

The review found no eligible studies for this question.

• Vitamin E for Alzheimer's dementia and mild cognitive impairment 2017 · 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