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Evidence found and GRADE certainty

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

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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 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