evidencegaps
Findings

What do systematic reviews say?

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

973 questions · 1,024 findings · 106 reviews

Sort:Best matchNewestHighest certaintyDownload CSV
No studies found 235 · 22.9%GRADE not reported 59 · 5.8%Very low 207 · 20.2%Low 271 · 26.5%Moderate 177 · 17.3%High 75 · 7.3%

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 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

Vitamin A and fish oils (docosahexaenoic acid) vs placebo, vitamins, or no treatment

Visual acuitychange in logMAR visual acuity, may be reported as ETDRS · retinitis pigmentosa

It is very uncertain whether vitamin A and fish oils (docosahexaenoic acid) changes visual acuitychange in logMAR visual acuity, may be reported as ETDRS compared with placebo, vitamins (including vitamin A), or no therapy (very low certainty).

1 finding from 1 review