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The Study

Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial.

In simple terms

This study gave different vitamin pills to thousands of people with eye problems and watched what happened over five years. It didn't prove that the new vitamins helped stop their eyes from getting worse, but it did find that one old vitamin (beta carotene) might increase lung cancer risk in people who used to smoke. So, we know what happened in this group, but we can't say for sure it would work the same for everyone.

74%

Analysis score

74/ 90

Maximum 90 for a randomized controlled trial.

Where the score came from

Reporting0
Methodology100
Publication100
Statistical77
Study type (basis of the score)
Randomized Controlled Trial
Level 1b - Individual RCT
What’s the bottom line?

Scientists tested if adding special vitamins (lutein, zeaxanthin, omega-3s) to a known eye supplement could stop old-age blindness from getting worse.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Randomized Trials
Level 1b
74

74 / 100

Quality score

Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.

Can establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1For most people, the vitamins didn't make a noticeable difference, but if you rarely ate leafy greens or fish, they might help — and beta carotene could be dangerous if you used to smoke.
  2. 2The vitamins didn't help most people — 31% of those on placebo got worse, and 29–31% on the vitamins got worse.
  3. 3But in people who ate very little of these vitamins before, taking them cut risk by 26%.
  4. 4Also, replacing beta carotene with lutein + zeaxanthin helped, but beta carotene raised lung cancer risk in former smokers.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

JAMA

Year

2013

Authors

E. Chew, T. Clemons, J. Sangiovanni, R. Danis, F. Ferris, M. Elman, A. Antoszyk, A. Ruby, D. Orth, S. Bressler, G. Fish, Baker Hubbard, M. Klein, S. Chandra, B. Blodi, A. Domalpally, T. Friberg, W. Wong, P. Rosenfeld, E. Agrón, C. Toth, P. Bernstein, Robert Sperdut

1252 citations
Analysis v6

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