evidencegaps
Findings

What do systematic reviews say?

Refine by population, intervention, comparison or outcome
More filters
Evidence found and GRADE certainty

1,126 questions · 1,225 findings · 111 reviews

Sort:Best matchNewestHighest certaintyDownload CSV
No studies found 235 · 19.2%GRADE not reported 260 · 21.2%Very low 207 · 16.9%Low 271 · 22.1%Moderate 177 · 14.4%High 75 · 6.1%

Vitamin C vs allopurinol

Acute gout attacks · participants with chronic gout and sUA level > 0.36mmol/L

The review found no eligible studies for this question.

1 finding from 1 review

Vitamin A vs placebo

Incidence: lung cancer · healthy people and healthy male physicians

Vitamin A showed no clear difference in incidence: lung cancer compared with placebo (high certainty).

1 finding from 1 review

Vitamin C vs placebo

Incidence: lung cancer ‐ women · healthy male physicians, period: 1997 to 2007 and female health professionals, period: 1998 to 2005

Vitamin C leads to higher incidence: lung cancer ‐ women compared with placebo (high certainty).

1 finding from 1 review

Vitamin C vs placebo

Mortality: lung cancer ‐ men · healthy male physicians, period: 1997 to 2007 and female health professionals, period: 1998 to 2005

Vitamin C showed no clear difference in mortality: lung cancer ‐ men compared with placebo (high certainty).

1 finding from 1 review

Vitamin C vs placebo

Incidence: all cancers · healthy male physicians, period: 1997 to 2007 and female health professionals, period: 1998 to 2005

Vitamin C showed no clear difference in incidence: all cancers compared with placebo (high certainty).

1 finding from 1 review

Vitamin C vs placebo

Mortality: all cancers · healthy male physicians, period: 1997 to 2007 and female health professionals, period: 1998 to 2005

Vitamin C showed no clear difference in mortality: all cancers compared with placebo (high certainty).

1 finding from 1 review

Vitamin A vs placebo

Mortality: lung cancer · healthy people and healthy male physicians

Vitamin A showed no clear difference in mortality: lung cancer compared with placebo (high certainty).

1 finding from 1 review

Vitamin A vs placebo

Adverse events: yellowing of the skin · healthy people and healthy male physicians

Vitamin A leads to higher adverse events: yellowing of the skin compared with placebo (high certainty).

1 finding from 1 review

Vitamin A vs placebo

Adverse events: minor gastrointestinal symptoms · healthy people and healthy male physicians

Vitamin A leads to higher adverse events: minor gastrointestinal symptoms compared with placebo (high certainty).

1 finding from 1 review

Vitamin A vs placebo

Incidence: all cancers · healthy people and healthy male physicians

Vitamin A showed no clear difference in incidence: all cancers compared with placebo (high certainty).

1 finding from 1 review

Vitamin A vs placebo

Mortality: all cancers · healthy people and healthy male physicians

Vitamin A showed no clear difference in mortality: all cancers compared with placebo (high certainty).

1 finding from 1 review

Vitamin A vs placebo

Mortality: all causes ‐ smokers and asbestos workers · healthy people and healthy male physicians

Vitamin A leads to higher mortality: all causes ‐ smokers and asbestos workers compared with placebo (high certainty).

1 finding from 1 review